Achieving a constant state of happiness first requires a profound understanding of oneself and an acute awareness of one’s reality. Recognizing that there must be a purpose behind human creation, I realized that lasting happiness and inner peace could only be attained by discovering this purpose and aligning my life accordingly. I understood that every new situation presented an opportunity to progress toward life’s deeper beauties. This transformation in perspective allowed me to derive personal satisfaction irrespective of external circumstances or conditions.

Over time, it became evident that life does not always unfold according to one’s wishes. Nevertheless, I came to accept that if the events shaping my path were part of a divinely orchestrated destiny, then they inherently held meaning and purpose. In a life plan uniquely designed for me, it would be impossible for a situation to arise that did not ultimately serve my benefit or growth. Thus, I began to view each experience as a carefully crafted treasure trove of lessons. Embracing the viewpoint that a believer, whether tested by hardship or blessed with prosperity, is always in a position of gain, I perceived every situation as a form of divine grace. Consequently, my foremost responsibility was to internalize this reality and actively incorporate it into my daily life.

However, the true meaning of life and my own place within it became fully clear during a profound period of captivity. The circumstances that led to my imprisonment were deeply political, rooted in the systematic repression carried out by the Erdogan administration in Turkey, under which mass arrests and detentions targeted individuals not for violence or crime, but simply for dissent. Despite the suffering, captivity became the place where I discovered the genuine beauty and deeper purpose of life. This experience exposed my human weaknesses and made real the truth of the saying, “pain matures the soul.” By consciously giving meaning to what I lived through, I reached a powerful realization: none of my experiences were wasted. Each one was a meaningful chapter in a greater story written for my growth.

Significantly, I understood that the suffering and pain I had perceived were often a product of my own distorted interpretations and judgments. Life itself, in its essence, resembled a beautiful book; yet when its beauty went unrecognized, it became akin to a story abandoned after its first page—empty, meaningless, and devoid of value. This recognition illuminated the importance of perceiving life as it truly is, rather than as it appears through the lens of emotional distortions. In this context, the insight of Bediuzzaman Said Nursi, a renowned Islamic scholar—”Those who see beautifully think beautifully, and those who think beautifully find joy in life”—emerged as a timeless guiding principle, highlighting the transformative power of perception.

People are asleep

My imprisonment became a means of awakening, an embodiment of the profound truth expressed by Prophet Muhammad (peace be upon him) in his saying, “People are asleep; they wake up when they die.” Within the solitude of confinement, I was afforded the rare opportunity to confront realities previously obscured by the distractions of daily life. I came face to face with what it truly meant to be human and acknowledged the deep dissonance between the truths I professed to know and the life I was actually living.

During this period of isolation, the words of Rumi resonated deeply within me: “Just as the thirsty yearns for water, the water also seeks lips to quench its own thirst.” In a similar vein, I came to believe that God had granted me this trial as an opportunity for my soul to quench its thirst for authentic meaning. All that remained for me to do was to offer boundless gratitude and praise to God for this unexpected blessing.

God-centered existence

The spiritual psychology expressed by Prophet Muhammad and some Islamic thinkers such as Nursi, and Rumi finds deep and striking parallels within Christianity and Judaism, revealing a shared understanding of suffering as a path to awakening and inner purification. In Christian theology, hardship is not viewed as meaningless pain but as a divine instrument through which the soul is refined and drawn closer to God, as reflected in St. Paul’s teaching that suffering produces perseverance, character, and hope. Similarly, Jesus’ life and suffering stand as the ultimate symbol of redemption, where pain becomes a gateway to spiritual rebirth.

Judaism likewise teaches that trials are a form of divine testing meant to purify the heart and strengthen faith, as expressed in Proverbs, which compares the human soul to silver refined by fire. This closely mirrors the Islamic belief that adversity matures the soul and unveils deeper truths hidden beneath the surface of comfort. In all three traditions, suffering is not a sign of abandonment by God, but rather an intimate form of divine engagement—an invitation to transcend the ego, correct one’s perception of reality, and awaken to a more meaningful, God-centered existence.

Crucible for awakening

Moreover, captivity revealed the extent of my spiritual thirst—for life, for belief, and for the values I claimed to cherish. Perhaps most startling was the realization that I had been completely unaware of this yearning. I had been consumed by worldly ambitions and fleeting pursuits, oblivious to how much of my life had slipped away. Prison, paradoxically, became the crucible for my spiritual awakening—a space where I recognized my inner desolation and began to take meaningful steps toward satisfying the deeper needs of my soul.

Upon recognizing the reality of my situation, profound regret washed over me. I mourned the years wasted in superficial pursuits; the time lost in the illusion of faith rather than its sincere practice. I wept for the lost opportunities to truly live by the teachings of the book of God, understanding belatedly that had I engaged with it with genuine reflection and earnestness, my life would have unfolded with far greater beauty and purpose. The realization that I had neglected such a profound gift for so long was devastating, yet also deeply transformative.

This confrontation with my own shortcomings revealed the fragility of my faith. The oft-repeated phrase “hanging by a thread” took on visceral meaning, deeply shaking my very foundations. I discerned how precarious my belief had become—despite having memorized the six pillars of faith in childhood, I had failed to internalize and live by them. I found myself grappling with profound questions: What does it truly mean to believe in God, in the Holy Books, in the Angels, in the Prophets, in the Day of Judgment, and in Divine Destiny? It became apparent that merely professing faith was insufficient; true belief necessitated active embodiment and practice.

This painful but necessary realization unveiled a critical gap between the beliefs I claimed to hold and the life I actually lived. In neglecting to live by my stated values, I had, instead, come to shape my beliefs around my experiences—believing as I lived, rather than living as I believed. Consequently, I had drifted far from the Scripture and the Prophetic path, relying instead on my own flawed interpretations. The life I had constructed was one of chaos and spiritual emptiness, starkly contrasting with the divine tranquility I had so long sought.

Through the struggles of imprisonment, I came to a profound understanding of divine testing. I realized that God tests His servants through hardship, not to break them, but to guide them back to Him. My life in prison was one such divine test, an opportunity for reflection and repentance. It was through this trial that I was blessed with an awakening—a renewed commitment to the values I once only claimed to uphold. For this extraordinary mercy, I offered unending thanks to God, fully aware that, had this trial not occurred, my life may have continued on a trajectory of unconsciousness and ultimate loss.

Having arrived at this realization, I turned to God with earnest supplication, seeking forgiveness, mercy, and the continued blessing of His guidance. I understood, with clarity and conviction, that enduring happiness and true peace, aligned with my faith, could only be attained through God’s favor and my unwavering commitment to live by the principles He revealed. In this, I found myself echoing the insight of Muhyiddin Ibn Arabi: that the real journey is not outward, but a return from myself to myself, discovering that every search, every struggle, and every moment of distance was, in truth, a path leading back to my own heart and to the presence of God. Thus, what seemed an external quest resolved into an inner awakening, realizing that the One I sought was never absent, and that my true task is to purify the self, recognize His nearness, and walk, with humility and love, in the light of His guidance.

Every human being asks the question “why,” though at different levels, to explain the unexplained. It follows a pattern of questions, like “Why did the financial crisis in the U.S. happen in August 2008?” “Why did the space shuttle Challenger explode?” “Why did the terrorists commit the September 11 attacks?” In statistical terms, such unexpected events are named “outliers,” however, they are part of the system and among the components constituting the overall system’s complex behavior. Thus, they need to be part of the explanation in order for the explanation to be complete. We are naturally tempted to come up with universal explanations of the complexity behind these major events so that we can be ready when a similar thing happens again. Though simple mathematical equations or relationships relate to us better and provide a universal explanation, they are typically practical only when the outliers are excluded from the system behavior. Statistics help us greatly in quantifying and characterizing the outliers, especially in the form of probabilistic expressions, such as “there is a 30% chance of a hurricane next week.”

Understanding the complexity around us involves the development of a model that is simple enough for us to comprehend but yet universal enough to capture most of the dynamics of the complexity. The simpler and the more universal the model, the more powerful it is. The universality of a model, however, is hindered by the potential inability to capture something unexpected. The tradeoff between simplicity and universality exists in all modeling efforts; and the models finding the delicate balance in this tradeoff are the most effective ones. A simple mathematical relationship known as “the power law” has been used extensively to characterize and model various natural and social phenomena.

What is the Power Law?

The “power law” does not refer to a misconception that “whoever has power will rule,” but rather it refers to a particular way of characterizing dependency between two quantities. When the number or frequency of an object or event varies as a power of some attribute of that object (e.g., its size), the number or frequency is said to follow a power law. In more general terms, there exists a power law relationship between x and y if y is growing or reducing polynomially when x is growing linearly (y _͌ x^–α). Mathematically speaking, this means that the relationship between y and x is mainly characterized by the exponent -a. An exponent is simply shorthand for multiplying that number of identical factors. So, 4³ is the same as 4x4x4; that is three identical factors of 4. As shown in Figure 1, a quantity with an exponent has three components: the base, the exponent, and the coefficient. So, for 4³, the base is 4, the exponent is 3, and the coefficient is an implicit 1.

Figure 1: Description of an exponent in a power law relationship.

Figure 2: Sample power law relationships between x and y, where y = x^–α.

The power law relationships are traditionally expressed with a negative exponent, which simply means the inverse of the quantity. That is, y _͌ x^–α is equivalent to y _͌ 1/x^α. For example, when a is 2, y will reduce from 1/4 (i.e. 0.25) to 1/9 (i.e. ~0.11) if x grows from 2 to 3. Likewise, when a is 0.5, y will reduce from 1/2 (i.e. 0.5) to 1/3 (i.e. 0.33) if x grows from 4 to 9. For those who enjoy graphs, Figure 2 illustrates these mathematical relationships in linear and logarithmic scales.

Power law on different scales: Atoms to planets

To start with, gravitation, acoustics, electrostatics, and light and electromagnetic radiation, all exhibit a form of power law in that physical quantity or strength that is inversely proportional to the square of the distance, which corresponds to a power exponent of 2. [1] Gravitational force between two particles, the electrostatic force of attraction between two electrically charged particles, the intensity of sound signals coming from a source, and finally the intensity of light or electromagnetic field coming from a source all follow a power law with respect to the distance.

What makes the power law relationships more interesting is their independence from scale or size of the measures being related to each other. This is why we sometimes call power law relationships as “scale-free” relationships or “scale-invariance.” For example, the gravitational force between two spherical particles decays with a power exponent of 2 regardless of the sizes of the particles though the actual force is certainly dependent on the particle sizes. So, the particles can be at nano scales (e.g. a group of atoms) or macro scales (e.g. a planet), but the relationship stays the same!

Power law in frequency: Wealth, terror, and earthquakes

A common usage of power law relationships has been to model and understand frequency of a varying measure. A power law typically very well represents the distribution of wealth in a society. [2] According to a recent study, the distribution of wealth in China during the years 2003–2005 follows a power law with an exponent ranging from 1.758 to 2.285. If we consider an average exponent of 2 for Chinese wealth distribution, this means that if there are 1 million Chinese people who owned $1000 there were 1000 that owned $1M. Thus, the power law essentially expresses how skewed the distribution of a frequency is (see Figure 2). The larger the power exponent, the more skewed the distribution. In this case, a larger power exponent means a more imbalanced wealth distribution while a power exponent of 1 refers to an evenly distributed wealth.

Many other social patterns exhibit power law. A recent study showed that it exists even in terror events! The number of casualties per insurgent event and the number of insurgent events per day follow a power law. [3] Historical data for the last two centuries show further that the number of casualties per war or a terror attack follows a power law distribution. What is even more interesting is that the number of casualties and the number of attacks within an insurgent conflict both follow power law. That is, when only a particular conflict between two countries or ethnic groups is considered, the number of casualties per insurgent event and the number of insurgent events per day follow the power law. This suggests a “self-similar” pattern. Likewise, traffic measurements for many systems show power law distributions of size. For instance, if one observes the data traffic on an Internet connection and counts the number of bytes being transmitted per hour over that connection, a power law distribution of the count of bytes will emerge. Further, if this counting is done per minute instead of per hour, a similar distribution will still emerge – again showing a self-similar pattern. [4]

The power law has been observed in several natural phenomena as well. The frequency of earthquake magnitudes follows a power law. [5] This refers to the intuitive notion that the number of earthquakes with small magnitudes (which humans do not even feel) is much larger than the number of earthquakes with large magnitudes, (which can kill many humans). Small earthquakes are the norm while large ones the outliers. However, without the outliers, there is no power law distribution! Thus, the power law distribution of a quantity comes with an interesting observation: If a quantity is indeed following a power law distribution, then the likelihood of an outlier event increases as the time goes by without an outlier event. This is why geoscientists would make comments like “The region X is due for a major earthquake!” indicating that the region X has not been receiving a major earthquake (i.e. an outlier) for several years. The issue, though, is determining the threshold for an outlier is typically ambiguous and may require many years of measurements and data, which may be impractical.

Power law in growth: Rich get richer

Growth of systems also exhibit power law in various ways. Social growth follows power law due to the well-known “rich get richer” rule, which refers to the intuition that “important” people in the society attract more of the attention of newcomers. This dynamic situation is observed, for example, in the growth of the Internet. Several studies [6] showed that the connections between Internet Service Providers (ISPs) (e.g., AOL, Yahoo!, AT&T, Sprint) follow a power law distribution in that the number of connections per ISP (which shows how well an ISP is connected to the rest of the world) is represented by power law. In other words, there are few ISPs with many connections to other ISPs while most ISPs have a few connections to the others. This is believed to be due to the “rich get richer” rule since an existing ISP with many connections is more likely to gain the business of a new ISP who is joining to the Internet. So, it is somewhat an economic pattern too.

If economics (or the money) is taken out of the picture, social growth still exhibits power law. Online social networks such as Facebook, LinkedIn, and Flickr are clearly following a power law distribution. It is found that the power exponents are in the range of 2.5 to 3.7, indicating a highly imbalanced social growth pattern where few people are at the “center” of the social network with hundreds or thousands of friends, and many people have only one or two friends. [7] Again, the typical explanation for this growth pattern has been the “rich get richer” rule, but “richness” refers to the number of existing friends in this context rather than money.

Physical growth shows power law too in many ways. For instance, roughness of a growing surface as time goes by follows a power law distribution with an exponent ranging between 0 and 1 where an exponent of 0 refers to a smooth growth and 1 refers to a stiff growth. The surface roughness is measured by the variance of heights of surface locations. [8]

Does it really exist? Why does it exist?

Verifying existence of a power law distribution is not easy and requires enough number of samples to show the “tail” of the distribution. The tail of the distribution refers to the samples with large (or rare) values. For example, for the power law distributions in Figure 2, the portion of the distribution when x is greater than 10 (i.e. x>10) roughly corresponds to the “tail.” The tail corresponds to the rare samples. Though statistical theory calls those rare samples “outliers,” the distribution will not be a power law distribution without them. They are strictly parts of pieces that constitute a power law relationship, and observing them typically requires long periods or large numbers of measurements. Due to this difficulty, the existence of the power law is questioned for many real systems. Most of the time, claims of the existence of the power law typically come with an error factor indicating the confidence of the claim. The bottom-line is to observe trends in the samples and thus establish sufficient confidence (e.g., more than 95%) that the power law distribution does exist in the samples.

For those systems with clear exhibition of power law, the root causes of it have been of high interest. The “rich get richer” rule is intuitively one of the root causes, and it is intuitively a natural dynamic to get attracted by a rich member rather than a poor one. Growth certainly naturally follows the “rich get richer” rule, but we have system components slowing their growth, flattening, and then deteriorating. So, not everything is growing, and actually, we have as many things deteriorating as growing. For instance, participants join or leave the Internet or the social networks, and likewise, people join (i.e. birth) or leave (i.e. death) society. How does the power law stay in such systems then?

Due to the “rich get richer” intuition, the power law is considered to be the signature of “self-organization.” The fact that so many natural or synthetic systems are exhibiting this signature deserves the question: “Is it really self-organization?” Maintaining a global power law distribution for a system requires either (i) every member joining or leaving the system according to the “rich get richer” rule and having global knowledge of the whole system or (ii) somebody who knows everything about the system and gives explicit direct orders to each member when they are joining or leaving. Which one is more likely?

Murat Yuksel is an Assistant Professor at the CSE Department of The University of Nevada – Reno (UNR), Reno, NV.

References

[1] Wikipedia, “Inverse-square law,” http://en.wikipedia.org/wiki/Inverse-square_law

[2] M. A. Santos, R. Coelho, G. Hegyi, Z. Néda, and J. Ramasco. 2007. “Wealth distribution in modern and medieval societies,” The European Physical Journal, Volume 143, Number 1, pages 81-85.

[3] J. C. Bohorquez, S. Gourley, A. R. Dixon, M. Spagat, and N. F. Johnson. 2009. “Common ecology quantifies human insurgency,” Nature, Volume 462, December, pages 911-914.

[4] T. Karagiannis, M. Molle, and M. Faloutsos. 2004. “Long-Range Dependence: Ten Years of Internet Traffic Modeling,” IEEE Internet Computing, September/October, pages 57-64.

[5] T. Lay and T. Wallace. 1995. Modern Global Seismology, Academic Press, San Diego, CA.

[6] M. Faloutsos, P. Faloutsos, and C. Faloutsos. 1999. “On power-law relationships of the Internet topology,” ACM Computer Communication Review, Volume 29, Issue 4.

[7] R. Kumar, J. Novak, and A. Tomkins. 2006. “Structure and evolution of online social networks,” Proceedings of ACM SIGKDD, pages 611-617.

[8] A. L. Barabasi and H. E. Stanley. 1995. Fractal Concepts in Surface Growth, Cambridge University Press, Cambridge, England.

The miracle of life appears in the form of a baby which develops from a fertilized ovule (zygote) following millions of other events. This series of events, which is almost always the same for every fetus, can be grouped as reproduction, differentiation, and development. The zygote completes its development in the womb; postnatal growth can continue until 20 years of age. Even though every event during the baby’s development seems to take place with chaotic reactions, harmony and order are there for us to discover. One of these astonishing events is the perfectly symmetric growth of the fetus/baby. Most organs in the human body appear in pairs and are symmetric. Babies are born with 300 bones; however, some bones later fuse with other bones, leaving only 208 bones in the adult human. It is still a mystery how long bones such as the humerus, radius, ulna, femur, and tibia are able to grow on both sides of the human body in a symmetrical manner.

Mechanisms that control growth in organs

In vertebrates, both internal developmental programs and the external factors which stimulate or inhibit growth play a role in the ultimate size of an organ. But the relative effects of these two mechanisms can vary significantly in different organs. When pieces of spleen from an embryo that is at a later stage of growth are transplanted to a newly developing embryo, each new piece grows, but not to the size of the original spleen. The total weight of all the transplanted spleen pieces is equal to a normal spleen’s weight. When the spleen reaches a certain weight, growth inhibiting factors are secreted, which stimulate negative feedback mechanisms that limit growth. When a spleen reaches a certain size, the density of the inhibiting factors increases simultaneously, halting growth. Growth in the liver is controlled by extracellular factors (various substances in the blood, hormones, vitamins, minerals, etc.). When a section is cut off of the liver, the section continues growing and developing until it reaches the size of the original liver. The thymus has a growth process that is executed by a cellular genetic program. When sections of a thymus taken from the embryonic period are injected into developing mouse embryos, every section grows until it reaches the ultimate size.

More evidence of cellular growth programs was acquired via an experiment that was carried out with the salamander genus Ambystoma. When the leg bud of the larger species was injected into the smaller species, it would at first grow slowly, but then it would reach the normal size of its own species (the larger species).

Distinguishing growth and symmetry from one another

Both the arms and legs have long bones. A long bone consists of two parts (diaphysis and epiphysis). The diaphysis is the middle (core) part of the long bone. It consists of hard bone tissue, and is like a tube. The hyaline cartilage-covered joint forms the epiphysis of the long bone. In a growing bone, there is a growth plate (epiphysis plaque) made of hyaline cartilage; this is located between the diaphysis and the epiphysis. The epiphysis plaque causes the bone to grow longer; when growth is complete, the epiphysis plaque ossifies (becomes bone). In other words, growth stops. There are some clues that show the existence of positive feedback mechanisms which control the symmetric and balanced development of the arms and legs while the fetus is still growing. The arms and legs grow due to the development and growth of the plaques located at opposite ends of the long bone. The ultimate size of the arms and legs are proportional to the size of the finger bones (phalanx) and the metacarpus. According to current knowledge, growth in our arms and legs is only controlled by internal growth programs and the active growth of the plaques. We do not yet know the mechanism through which how much the bone must grow and symmetrically with the organ (the other arm or leg) on the other side of the body. But even if this is discovered in the future, we will continue to appreciate the perfect and miraculous aspect of this phenomenon.

In addition, in growth-plaque transplant experiments, the development of the transplanted growth plaque is dependent only on the age and size of the donor. Growth plaques cause the bone to grow, but the plaques themselves remain the same size for years. The cartilage cells they produce (chondrocytes) exchange places with the bone cells (osteocytes) in harmony and without destroying the length of the bone. Cells from different areas of the growth plaque act differently. Stem cells are found on the upper section, near the epiphysis. Immediately above them is an area where cells reproduce very quickly. At the bottom of the epiphysis, the cartilage cells grow up to 4 to 10 times larger than their normal size (hypertrophy). Cell reproduction here is mostly due to hypertrophic chondrocytes. The chondrocytes die and break up, then change places with the bone tissue. The dynamic process of these events in the growth plaque repels it from the bone area, and as a result, the bone grows longer.

Sustained symmetry despite cell sequence and speed of reproduction

The rapid growth rate in the legs and arms during the embryonic period continues to increase until the child is three years of age. This growth rate slows down until the individual reaches adolescence. During the fastest growth period, which is from adolescence to the early 20s, the growth rate rapidly increases. For example, most people who grow between 30 and 37.5 cm during the first two years of life can grow between another 7.5 and 10 cm every year during adolescence. At the onset of adolescence, rapid growth due to a sudden change in the volume of cells is observed. After adolescence a sudden falling off in the speed of growth can be observed due to the effect of hormones on the growth plaques in the spine and other long bones. The growth plaque now fuses with the neighboring cells and growth stops. However, the fusing of the growth plaque is the result of the cessation of growth, not the cause. After growth stops, the growth plaques begin to disappear. When the reproduction potential of the cartilage cells in the growth plaque has been exhausted, the growth plaque begins to disappear.

Growth plaques in different bones can trigger growth at various rates; these rates can differ as much as seven times. In fact, growth plaques on different ends of a bone can have different growth rates, provided that this rate is consistent with the genetic program. The number of cells on the growth line is 40 times more than in other areas. The number of cells produced here can exceed 10,000 cells per day. For symmetric growth between the arms and legs to be sustained, the number of cells in the growth plaque must be the same or very close. Experiments carried out on rats show that eight cartilage cells leave the growth plaque to exchange places with cells above them every day. It can be said that the growth of the bone is caused by the increase of cells in the growth plaque (which sustains its size). The growth rate caused by the growth plaque can be calculated by multiplying the growth plaque’s cell production rate by the average length of all of its cells. Different growth plaques provide different growth rates. This difference can be caused by the difference in the size of the growth plaques, the difference in cell production rates, and/or the difference in the hypertrophy (growth) rate of every cell. The upper growth plaque in the tibia of mice generates 16,400 cells every day; the average life span of these cells is around 30 hours. Can such harmonious, symmetric, and equivalent growth in the arms and legs-despite the large number and variety of cells-be the work of pure coincidence, mindless nature, or unconscious molecules?

Do hormones play a role?

The main molecular players that organize longitudinal growth in bones during childhood are the growth hormone, the thyroid hormone, and corticoids. The sex hormones (androgens and estrogens) are programmed to influence growth during adolescence. Estrogen is the main determiner of characteristics related to increased height and an increase in bone quality, as well as adolescent-related physiology. These hormones are in charge of coordinating growth throughout the body. It is for this reason for women, after the menopause, the production in estrogen decreases and osteoporosis and brittle bones can occur. According to the current view, cartilage cells have a certain genetic reproduction potential, and when this potential finishes, growth stops. The growth rate during the embryonic period is 20 times higher than that of mid-childhood. The growth rate drops greatly during mid-childhood. If we exclude the noticeable increase during adolescence, the cells responsible for growth have begun to age. The bones on opposite sides of the body stay about the same size, despite all of these changes in growth rates. Circulating hormones and neuroendocrinal factors are believed to play important roles in maintaining symmetric growth. But there is no conclusive evidence to support this belief. Even though one can think of factors such as pressure, tension, and sports as helping control harmonious and symmetric growth of bones, no proof has been attained from controlled experiments. As a person ages, a gradual decrease in growth can be observed. Even if a growth plaque is placed into another organism, be it young or old, the growth rate of the bone does not change. This shows that symmetric growth in long bones is controlled by a program that is operated by internal factors, which is also compatible with the genetic program. When chemical-based medication is given to postpone growth, after the medication has been eliminated, the growth plaques grow faster for a short period to compensate for the lost time. These findings show that timing and the location and circumstances of the cell are critical parameters for reproduction. If the cartilage stem cells in the growth plaque have a certain reproduction potential, then it is clear that cartilage cell reproduction stops when growth comes to an end. If growth inhibiting factors slowly accumulate in the growth plaque, this might cause a deceleration of growth over time. Another possibility is some sort of “meter” in the unconscious and mindless stem cells, which keeps track of the number of cell divisions and thus controls aging. The estrogen in our body has a duty of closing down the growth plaques and speeding up the aging of cells. However, we should not forget that estrogen plays the special role of closing down all of the growth plaques at the same time. Estrogen is one of the visible causes of fertility, growth and development, and resilience. Estrogen also represents femininity and fertility at all levels.

When the signals from unconscious cells in the growth plaques and the quite sophisticated interactions among all the factors that influence growth, all of which require an all-encompassing knowledge to be executed, are taken into account, the impeccable genetic programs of different growth plaques on the two sides of the body that leads to the formation of the arms and legs, as if they have been molded in a factory, is absolutely amazing for anyone who reflects upon it.

References

• Wolpert L. (2010).”Unsolved Mystery: Arms and the Man: The Problem of Symmetric Growth.” PLoS Biology. 2010 Vol. 8(9). pp 1-3
• Extremity Development during the Embryonic Period (www.visembryo.com)

At the beginning, I really did not pay much attention to him. He was very small, almost invisible and harmless-looking. However, he started to reproduce all of a sudden. Now, there were billions of his copies on one of my leaves. Everything was happening so quickly. They were taking me over. Something had to be done urgently.

As plants, we cope with such environmental stresses everyday. If the stress factors affecting us are living organisms, such as bacteria, harmful insects, and weeds, we call those as biotic stresses (1). On the other hand, if we are exposed to drought, salinity, heat, cold, and deficiency or excess of a chemical in soil, those are abiotic stresses for us. Both biotic and abiotic stresses impair our growth and even lead to our death sometimes. Therefore, stress response mechanisms are very important for us. Unfortunately in the United States alone, crop losses due to plant pathogens amount to billions of dollars (2). As we are the main food resource for the humans and assigned for so many other important functions on earth by God, our health and productivity is taken very seriously by scientists. So, it is of great interest to them to find out how our defense responses against microbes work. If scientists learn what is going on when a plant is infected by pathogens thoroughly, they can introduce better resistance mechanisms into economically important crop plants via genetic engineering.

Oh “NO,” I am stressed!

Unlike animals, we are firmly attached to the ground so we can not escape from stress factors. However, thanks to God, we have fascinating defense mechanisms against environmental challenges. First of all, I need to know who this infectious agent (pathogen) is so that I can trigger a stress response mechanism against it. The interactions between me and these microbes are controlled by my receptor proteins and Pathogen-associated molecular patterns, or PAMPs, delivered by the pathogen. PAMPs help pathogen growth by suppressing my defenses and manipulating my metabolism (3).When I recognize a PAMP by my receptors, I activate a set of defense mechanisms known as the hypersensitive response (HR) to arrest and terminate pathogen growth before it terminates me (4). Just before or in conjunction with HR, I increase synthesis of several families of pathogenesis-related (PR) proteins in my infected part (5).

Do you want to know what I do after I identify a pathogen? I bet you do, so I am going to tell you about the other components of my signal transduction cascade that is activated upon brutal attack of microbes (Fig. 1). One of the early steps in this signaling cascade is the elevation of cellular calcium (Ca (2+)) levels mediated by my plasma membrane and channels such as cyclic nucleotide gated channels (CNGCs). After the initial Ca(2+) increase, I activate some of my calcium-binding proteins (calmodulin or CaM) and protein kinases, which modify other proteins by chemically adding phosphate groups to them, and ultimately I generate nitric oxide (NO) and reactive oxygen species (ROS) (6). ROS function as signaling molecules that coordinate a wide range of diverse plant processes, such as growth, development, stress adaptation, and cell self-destruction (programmed cell death) (7). However, the real reason I produce ROS under attack is to use them as local toxins to form unfavorable conditions for pathogen growth and reproduction. NO plays a key role in our immunity in synergy with ROS regulating responses that include defense gene expression and programmed cell death (8). As a result, I utilize both ROS and NO to say “NO” to the pathogens. Other important signaling molecules I utilize are salicylic acid and jasmonic acid. These essential plant hormones are chemical messengers that enable me to respond to my environment. Salicylic acid, SA, which is chemically similar to but not identical to the active component of aspirin (acetylsalicylic acid), is involved in the defense against pathogens that feed and reproduce on live host cells and activates signaling processes providing systemic acquired resistance, protecting the plant from further infection after an initial pathogen attack (9) (Fig. 2). On the other hand, jasmonic acid (JA) induces defense against pathogens that kill host cells for nutrition and reproduction (10). Another hormone in the complex cross talk of signaling pathways regulating my defense responses to microbial attack is ethylene, ET (11).

Although, I have not even told you all the details, I bet you have started to think that all these signaling cascades, regulators, hormones, molecular patterns, and receptors are highly complicated. Do not worry; I am not planning to tell you all the molecular mechanism(s) and relevant pathways I execute during biotic stress responses. If I do, then what will the plant scientists who are interested in plant pathogen interactions do for the rest of their lives? Instead I am going to briefly describe to you what strategies I use to prevent the spread of infection that the small microbe started.

Initially, I build physical barriers around the infection by increasing my cuticle, a protective waxy covering, and cell wall thickness, and then I release antimicrobial compounds, such as phenolics and phytoalexins to the sites of invasion (11). However, this effort is usually not enough to stop the microbes. Therefore, most of the time, the cells in the local region surrounding the infection decide to commit suicide to limit the growth of the pathogen through programmed cell death, which is a highly coordinated and sophisticated phenomenon. This resembles to the firefighters’ strategy to put down a forest fire. Firefighters control flames by cutting down trees, clearing brush away from the existing edge of the fire. This way they can form borders to mitigate the forest fire.

While I am fighting the infection, I also try to confer a long-lasting protection against this pathogen. I send mobile signals like salicylic acid to activate defense responses in distal tissues in case a secondary pathogen attack might occur there (12). Salicylic acid also induces numerous genes that encode PR proteins with antimicrobial properties (13).

I have done all those things I have told you here and a lot more that are still undisclosed to humans in a really short time because it was a matter of “to be, or not to be.” After all that stress, I have won the battle against the microbe at least for now. I have gained a life experience and will defend myself better in the future. I am recovering, but unfortunately my leaf, where all that fighting happened, has a big lesion, an abnormal tissue, which was formed when my poor cells died during the attack (Figure3).

As you can tell from my story, plants get stressed out too. However, we are not stressed due to problems at home, school, or work or spending time stuck in traffic. We deal with salinity, heavy metals, temperature, drought, lack of nutrition, herbivores (insects, mammals, etc.), and pathogens. Thanks to God that He gave us astonishingly complicated response mechanisms to resist all sorts of stresses to some extent, especially biotic stress. Otherwise, we might have become extinct. Can you imagine a world without us? You would have no more oxygen in the air, no more food for animals and humans, no more papers or books, no more clothes, no more furniture, no more blooming beautiful gardens, no more roses for your loved ones, and no more trees, which hold the soil in place so that wind and rain don’t cause severe erosion and destruction of homes for so many species. In addition, there will be fewer resources for drugs and dyes. Oh my God, you are the Most Gracious and the Most Merciful. Thank you that You created us, shaped us and gave us smell, taste, color, and resistance to stresses.

Safiye Arslan is a research fellow in the area of biological chemistry and lives in Nevada.

References

1. Holopainen JK, Gershenzon J. 2010. “Multiple stress factors and the emission of plant VOCs.” Trends Plant Sci. 15,176–184.

2. http://www.apsnet.org/online/feature/biotechnology/

3. Wulff BB, Chakrabarti A, Jones DA. 2009. “Recognitional specificity and evolution in the tomato-Cladosporium fulvum pathosystem.” Mol Plant Microbe Interact. 22, 1191–202.

4. Genger RK, Jurkowski GI, McDowell JM, Lu H, Jung HW, Greenberg JT, Bent AF. 2008. “Signaling pathways that regulate the enhanced disease resistance of Arabidopsis ‘defense, no death’ mutants.” Mol Plant Microbe Interact. 21, 1285–96.

5. Klessig DF, Durner J, Noad R, Navarre DA, Wendehenne D, Kumar D, Zhou JM, Shah J, Zhang S, Kachroo P, Trifa Y, Pontier D, Lam E, Silva H. 2000. “Nitric oxide and salicylic acid signaling in plant defense.” Proc Natl Acad Sci USA. 97, 8849–8855.

6. Ma W, Berkowitz GA. 2007. “The grateful dead: calcium and cell death in plant innate immunity.” Cell Microbiol. 9, 2571–85.

7. Gechev TS, Van Breusegem F, Stone JM, Denev I, Laloi C. 2006. “Reactive oxygen species as signals that modulate plant stress responses and programmed cell death.” Bioessays. 28, 1091–101.

8. Asai S, Yoshioka H. 2009. “Nitric oxide as a partner of reactive oxygen species participates in disease resistance to nectrotophic pathogen Botryis cinerea in Nicotiana benthamiana.” Mol Plant Microbe Interact. 22, 619–29.

9. Beckers GJ, Spoel SH. 2006. “Fine-Tuning Plant Defence Signalling: Salicylate versus Jasmonate.” Plant Biol (Stuttg). 8, 1–10.

10. Spoel SH, Johnson JS, Dong X. 2007. “Regulation of tradeoffs between plant defenses against pathogens with different lifestyles.” Proc Natl Acad Sci USA. 104, 18842–7.

11. Bouchez O, Huard C, Lorrain S, Roby D, Balagué C. 2007. “Ethylene is one of the key elements for cell death and defense response control in the Arabidopsis lesion mimic mutant vad1.” Plant Physiol. 145, 465–77.

12. Ficke A, Gadoury DM, Seem RC, Godfrey D, Dry IB. 2004. “Host Barriers and Responses to Uncinula necator in Developing Grape Berries.” Phytopathology. 94, 438–45.

13. Liu PP, Bhattacharjee S, Klessig DF, Moffett P. 2010. “Systemic acquired resistance is induced by R gene-mediated responses independent of cell death.” Mol Plant Pathol. 11, 155–60.

14. Durrant WE, Dong X. 2004. “Systemic acquired resistance.” Annu Rev Phytopathol. 42, 185–209.

Shadowing effect: the game of who is taller

When sunlight falls on Earth, some shadowy areas do not receive it due to an elevated structure nearby. This causes the shadowy areas to have a different set of plants, which are usually shorter and smaller than the plants in the sunny areas. In brief, the shadowing effect is the input (here sunlight) reception behavior caused by height differences across a surface. The game here is that the taller ones grab more input than the shorter ones. In systems where the input is some kind of material falling on the surface, the most important outcome of the shadowing effect is slowly-rising columnar structures. The ultimate surface morphology depends heavily on the strength of the shadowing effect. Hills of snow following a heavy snow fall and forests with trees of various heights are examples of the shadowing effect.

Reemission effect: the game of reflections

When things bounce, they follow certain physical rules. When you throw something, it may stick or bounce depending on several factors. For instance, when the light falls onto a surface, some of it penetrates the surface and gets absorbed while the rest gets reflected. Reemission is another name for bouncing or reflection in physics, though the idea is not just equivalent angle reflection or equivalent reaction force bouncing.

Figure 1 illustrates the shadowing and reemission effects on a sample surface with hills. Falling particles will most often hit the hills first due to the shadowing effect. If the hill cannot grab the particle on the first hit, then the particle reemits, and it becomes possible for the particle to fall into a valley. In order for a particle to settle in a valley (e.g., particle B in Figure 1), it will have to go through a sequence of reemissions. Let’s say that a particle’s reemission probability (i.e., residual of the sticking coefficient) is p during a hit onto the surface. By simple math, if k reemissions are needed in order for a particle to settle in a valley point, then the probability of this valley point grabbing a particle is while it is for a hilltop under no shadow. In this very approximate model, k will be larger for a deeper valley point, thereby further reducing the grab probability. To get a quick sense of it, for p=0.5, the grab probability is 50% for a hilltop and 25%, 12.5%, and 6.25% for valley points with k=1, 2, and 3 respectively. Similarly, the parameter p represents the importance the of reemission effect in the growth of the surface. Higher p means more reemissions and a larger grab probability for valley points. That is, for p=0.9 (which means the material reemits 90% of the time), the grab probability is 10% for a hilltop; and 9%, 8.1%, and 7.3% for k=1, 2, and 3 respectively.

Intuitively, when the shadowing effect is dominant, the hills will grow larger and maybe merge with each other while sites at the valleys will remain short. The final surface will not be smooth but rough. Figure 2 shows this phenomenon on the macro scale for Tibetan forest growth under the shadowing effect, and Figure 3 shows it on the nano scale (1 nanometer corresponds to 1 billionth of a meter or about hundred thousand times smaller than the diameter of a human hair) for growth of nanostructures like nanorods (i.e., sticks at nanometer lengths). When the reemission effect is dominant, one can expect that the hills will get eliminated as the valleys will quickly grab the reemitted particles. In this case, the final surface will be smooth with evenly distributed growth.

Scientists have been using these effects to control the growth of the surface, especially recently for nanostructure growth. By changing the material characteristics (which affects the reemission probability) or the angle at which the atoms arrive at the surface (which affects shadowing), the scientist can control the dominance of the shadowing or reemission effects [3]. The final outcome of the nanostructures depends on other factors as well, such as (i) temperature of the substrate surface, (ii) energy of the particles, (iii) movement of the underlying substrate, and (iv) the initial pattern of the substrate as in Figure 3(b). By using a combination of these techniques, designers have been able to grow interesting structures such as nanosprings as shown in Fig. 3(b), or nanoballs as in Fig. 3(c). These nanostructures attracted the interest of researchers for various applications such as biosensors [4], engineering of light propagation [5], and microchip production [6].

A social perspective

It is not hard to see the role of shadowing and reemission effects on people and social growth as well. One typical tendency is that well-connected and well-known people or institutions are more likely to grab attention of newcomers to a society or a network. This phenomenon has been regularly observed in the growth of online social networks (e.g., Facebook) [3]. Similarly, wealthier people are more likely to receive a larger share of the aggregate social revenue, which yields a highly skewed wealth distribution. These social trends exist for valuable goods (i.e., “attention” in the former example and “money” in the latter) which have a high “sticking coefficient” and less reemission probability. A well-known phrase to describe this is “the rich get richer,” which Figure 3(a) clearly reveals, showing nanorod growth with a highly sticky material, silicon.

“Equal sharing” in societies is certainly achievable through a more dominant reemission effect. An analogy between reemissions and charity (or helping others) is plausible. Again, the social tendency has been to equally share (or reemit) items that are mostly commodity. Water, electricity, education, and health are examples of such commodities that people “reemit” in many societies, though even the water is not reemitted in some societies.

Conclusions

The interesting observation we would like the reader to recognize here is that shadowing and reemission effects take place at nano as well as at macro levels, and both play important roles in shaping formations or structures. Though these effects are mainly studied in physical structures, they certainly exist in unphysical structures such as societies. Sharing both physical wealth and knowledge is strongly advised for a strong community that lives in harmony. This is similar to the reemission effect during the growth of materials on the nano scale, in which reemission leads to smoother and denser films with structural integrity. On the other hand, when reemission is poor and the shadowing effect is dominant, it leads to isolated structures that look nicer but are structurally fragile (See Figure 3).

Dr. M. Yuksel is an Assistant Professor at the Computer Science and Engineering Department of the University of Nevada, Reno. Dr. T. Karabacak is an Assistant Professor at the Applied Science Department of the University of Arkansas at Litte Rock. Dr. H. Guclu is an Assistant Professor at the Biostatistics Department of the University of Pittsburgh.

References

1. T. Karabacak, H. Guclu, and M. Yuksel, “Network Behavior in Thin Film Growth Dynamics,” Physical Review B, 79(19), May 2009.
2. D. Winkler, “Patterns of forest distribution and the impact of fire and pastoralism in the forest region of Tibet,” In: G. Miehe and Y. L. Zhang, Editors, Environmental Changes in High Asia. Selbstverlag der Marburger Geographischen Gesellschaft, Marburg 135, pp. 201–227, 2000.
3. T. Karabacak, G.-C. Wang, and T.-M. Lu, “Physical self-assembly and the nucleation of 3D nanostructures by oblique angle deposition,” J. Vac. Sci. Technol. A 22, pp. 1778, 2004.
4. J.-X. Fu, A. Collins, and Y.-P. Zhao, “The optical properties and biosensor application of ultra thin Silver films prepared by oblique angle deposition,” J. Phys. Chem. C 112, pp. 16784–1679, 2008.
5. D.-X. Ye, Z.-P. Yang, A.S.P. Cang, J.Bur, S.Y. Lin, T.-M. Lu, R.Z. Wang, S. John, “Experimental realization of a well-controlled 3D silicon spiral photonic crystal,” J. Phys. D: Appl. Phys., 40, pp. 1, 2007.
6. P.-I. Wang, S. H. Lee, T. C. Parker, M. D. Frey, T. Karabacak, J.-Q. Lu, and T.-M. Lu, “Low temperature wafer bonding by copper nanorod array,”, Electrochem. and Solid State Lett., 12, pp. H138-H141, 2009.
7. R. Kumar, J. Novak, and A. Tomkins, “Structure and evolution of online social networks,” Proceedings of the 12th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, pp. 611-617, Philadelphia, PA, August 2006.

Just like the alternation of the day and the night with the succession of the light after darkness in every twenty-four hours, the rising and regression of nations have always occurred in successive turns of prosperity and hard times.

As for the leading figures of these nations, we see them swaying backward and forward with transformations and alterations, once in love with religious devotion and piety, at a different time bewitched by the things of this life, and yet at other unfortunate times captured in the web of materialism with no righteousness, morality, or character.

As a matter of fact, it would be quite wrong to conceive of any state or nation that is on the rise, taking root everywhere, as making consistent progress on a single plan and seeing it all religiously-oriented and heavenly-driven with regard to their rule and influence. Following their creation, everything enters into the process of growth, finds itself on the path of expansion and the ramp of ascension; however, only those upon whom fate smiles grow and flourish, and everything that grows is bound to die sooner or later!

To the extent of our interconnectedness with the cosmos and events, we can observe and witness all this phenomena unfolding before us every day. As we peruse the existence and events around us, if we can direct our thoughts and imagination towards historical occurrences as the consecutive projections of each other or as the overlapping pile-ups on top of each other, then we will testify that the world has turned green and blossomed, has tidied up and gathered strength, has revived and stood back on its feet as many times as it has stumbled and fallen over.

We are astounded by the moribund communities and nations, which, like the leaves caught in an abrupt gale or the ivy whose branches are torn off and yet cling to or twine about any support so as not to topple down, get back to their previous track, make great efforts with avidity, and speed towards their time of greatest power and authority. They gush out suddenly and unexpectedly, looking forward to rebirth, as if in an undeveloped shoot of plants, within the most indistinct and tiniest hollow on the stem, rooted in the past with the strength for growth after their decline; they run to grow by clinging to the points of support like ivy plants and try very hard to have springtime just once more.

Who knows how many times the roots, stem, and the branches of the society have been shaken with tempests! Who knows how many times it turned pale from the ice-cold and became ash gray under the heat of sun! Who knows how many times it has risen again in various spheres and grown rife! If the falls have taken away some part of its life and vigor, the springs have embosomed it so intimately with sparkling colors that everything else is discolored and all deceptive colors fade away one by one.

After seeing everything in an astonishing harmony, composed of teensy weensy constituents mixing up quietly and fascinatingly-seeing all these resuscitating in an unexpected manner and with an unanticipated liveliness, how can one ascribe this captivating vitality that looks like stillness and this unity that gives the impression of disorderliness to the true and eternal death and departure? Besides, even if this is temporarily so, every winter is followed by the spring and every night by the day.

From the point of recurring occurrences in history, it was nothing but such empty words heard at the beginning of the twentieth century: “Religion has been defeated by positivism” (as was formed in the mind of those with deviant thinking), “the spirit is down and out in the face of materialism”; “the atom is the essence of everything”; “the existence of all is dependent on material things”-it was such codswallop in the ears. Since the notion of energy was not fully comprehended, the atom was accepted as an unquestionable whole in those days. Before the turn of the second half of the twentieth century, however, materialism was shaken with the first surprising blow from within the circle of their own. It struggled with and got defeated by the perception of its inherent power (energy). Even if energy was not known in all its complexity at the time, it started to show its teeth, becoming more cognizable through the effects of its work. At the time, physics was aware of only its doings and not of energy itself; science considered energy as the capability of the matter or a physical system to carry out work. The science of physics had no knowledge of the real nature of this capacity, its general features, and its qualities.

The coming of energy into prominence occurred at the same time as the materialist philosophy entered into the sphere of the unknowns, chasms, and hardships. It was at this time that matter was believed to have the capability of turning into energy, journeying in the same realms with the spirits. According to the reality of the time, matter-something regarded as the proof for materialism-actually testified against materialism. If the atom is a power compressed and placed in a micro body and has the capability of not yielding to force and if all existence and incidents are created within this fountain of power and are endowed with their latent energy to full growth, those who discovered this immense power whose magnitude is accepted as not measurable in numbers and who burned down Hiroshima and Nagasaki did indeed not only put materialism to death but also trumpet forth its historic death while they were enunciating its enchanting efficacy only upon that occasion.

Everybody knows the rest of the story; we have witnessed the defeat of the forged system based on materialism-a deceiving system with its formation of the family and the society, its social and economic structure, its understanding of arts and esthetics, and its interpreting power of things and beings.

After all that bloodshed, casualties, and financial loss and all those years of life spent in vain, now we are once again ushering in the profundity of faith and spiritual thinking with the perception transcending matter and all existence. This was experienced before when we felt the universal truth in our pure conscience and had welcomed a glorious period of eight hundred years after being long exposed to such kind of chaos and disturbances a thousand years ago.

It is beyond doubt that the most influential power in the establishment of such a glory surpassing everything else belonged to faith. Thanks to faith that our society moved from the mundane to the spiritual life, from chaos to the order, from emptiness to the ideal, from narrowness of mind to the immenseness far beyond this world and the other world and became aware of the depth and extensiveness of their scope. It rediscovered its true worth and merit, its particular way of life, the refinement and grace it had lost long; it embraced and adopted faith most sincerely and had a life in a manner appropriate to heaven. It had such a pious life turning its deeds into worship, its talk into prayer, its appearance into gracefulness and mercy, and its unity into power. Thanks to faith that it found the way from emotion to soundness and sensibility, from logic to heart, and from reasoning to the insight and inspiration and thus stepped up and elevated itself. It found out the secrets of eternal subsistence all the way through feeling and thought, culture, arts, and esthetic delights.

We have every confidence in the belief that the chaos and dismay of today will be followed by the same heavenly victories and will experience a revival. We believe wholeheartedly that we will acquire once more what we have lost by means of the coming people of the heart who will find remedies for our wretchedness and sufferings, elevate our souls to the profundity of their own, and direct them from there to the real Source of everything. We can even call it our renaissance if this labeling will not be considered a fantasy.

It undoubtedly is necessary to prepare the way for this rebirth. The dynamics and potentials available in all the spheres of the society, including educational institutions, houses of prayer and worship, military quarters, and religious centers and lodges will be utilized for this purpose. All this preparation, however, will be fulfilled not by cumbrous institutions that are retired into themselves and consoled only by distinctive titles and designations, that think of nothing else except for their share of the appropriation but by the integrated institutions founded upon the concord of heart, soul, mind, and discipline as well as by those luminous scholars and intellectuals who believe in justice and have a sound character, mentality, and worldview and who blend all these with a faithful culture that has been acquired over hundreds and hundreds of years. It will be realized both by educational institutions that are represented by the lovers of knowledge and wisdom who are united with the truth in body, spirit, intellect, and zeal and by the people of truth with a sound character who get to work with the consciousness of duty, who act not just simply to save the day, and who seek ways to strive for their cause rather than trying hard for the satisfaction of the desires and pleasures of their own.

Aware of the fact that we are now at such a turn in the recurring events of history, we reexamine our conscience and smile at our fate with confidence in our auspiciousness.

The 2006 World Development Report analyzes the relationship between equity and economic development in Developing countries. In this essay, I re-examine the relationship between equality, equity and development from a long-term economic development perspective. Equality refers to the condition where socioeconomic groups, i.e. upper, middle and lower classes, in a society have access to relatively similar levels of income. Equity, however, roughly corresponds to the broader term of human development,² and emphasizes equality of opportunity, and a broader set of human conditions. In the light of this report by the World Bank, I suggest that contrary to the long-held views, the development of contemporary Developing countries can only be achieved by “leveling the playing field” among citizens.

For long years, it was believed that economic development led to human development. it was assumed that as a country develops economically, it is able to provide more for the basic needs of its citizens such as education, healthcare, and a better quality of life. Even though it seems reasonable to expect improvement in individuals’ quality of life as a country develops, we have not observed many countries successfully achieving this better quality of life by following the advice of policymakers. However, a casual observation suggests that the relationship between economic development and human development may be endogenous; that is, just as it is natural to expect economic development to affect human development, we should be able to observe various aspects of human development shaping the course of development of many Developing countries. In fact, many Developing countries such as India and Turkey perform better in measures of economic development due to their higher levels of educated citizens.

Equality – development tradeoff

Following Simon Kuznets’ (1955) pioneering study on the relationship between economic development and equality, academicians and policymakers believed that there exists an inherent trade-off between economic development and socioeconomic equality. The dominant perspective places economic efficiency concerns at the center of this tradeoff .³Equality-enhancing redistribution programs lead to “diversion of resources away from their most efficient use.” According to this view, employing limited resources in welfare-improving areas results in a decrease in economic growth as well as underutilized resources. Instead of employing the relatively scarce factor of production, that is capital, in new investment opportunities which would economically be more efficient, spending the capital on less productive social redistribution would negatively affect the economic development hopes negatively.

The main alternative view highlights the welfare consequences of the presumed tradeoff between growth and equality. Proponents of this perspective claim that a focus on rapid growth is likely to entail “distorted patterns of development” and to reduce the welfare of the poor in the society. In particular, the state along with the actors in the private sector directs its focus on increasing productivity and efficiency in the manufacturing sector. Any financial commitment that potentially decreases efficiency in the economy is strictly avoided; redistribution to the poor in the society is considered among such expenditures. The socio-economic distress of the poor simply takes a backseat vis A vis economic efficiency. In order to minimize the short-term effects of the growth-oriented economy, equality should take precedence over economic growth. In the long-run, equality will positively impact economic development.

A recent report by the World Bank draws attention to this widely-accepted tradeoff between development and equality,⁴and proposes an alternative. The report claims that equality and development are complementary to each other rather than contradictory. Economic growth without equality can only provide distorted patterns of economic development leaving the majority of the population in need, just as we observe in many Developing countries today. On the other hand, an exclusive focus on equality is likely to hinder development as valuable resources at the disposal of capital-holders are diverted from their efficient use. As a result, a long-term solution to this impasse requires the introduction of a delicate trade-off between the two: Investment in human. Human development, hence, lies at the heart of this new conception of economic development.

Equity and equality

Equality, in the conventional sense of the term, refers to the elimination of extreme disparity with respect to wealth among individuals within a given community. For this end, different states have applied various forms of redistribution in order to eliminate inequality of income. Such use of the term mostly taps into the outcome aspect of equality. That is, the goal is to minimize the differences in incomes of the people by redistributing wealth from the rich to the poor. Equity, on the other hand, is the new term offered by the World Bank to development terminology. Equity is based on a larger conceptualization of the notion of equality. It suggests equal opportunities in respect to education, health and such; no explicit implication is being offered for the outcome-based notion of equality. Individual responsibility, in this regard, is critical in bridging equal opportunity at the outset with the final outcome.

John Rawls’ notion of the “veil of ignorance” summarizes the basic idea behind this contemporary understanding of equity.⁵ The veil of ignorance is expected to provide a fair allocation of resources that all members of a society would agree. In a hypothetical decision-making situation prior to their knowledge of which position they would occupy in the society, individuals are asked to allocate resources to members of the community; they may be the worse-off or best-off in the community, hence they will put an effort in fairly allocating the resources. In essence, Rawls concludes that “primary goods” should be provided for all, referring to the equality of opportunity for all. Amartya Sen dwells on a similar concept of primary goods, “functionings,” and defines it as “the set of actions a person performs and of states the person values and enjoys.”⁶ It is important to recognize the fact that no suggestions are being made here with respect to the conventional understanding of equality, that is income redistribution. The emphasis in this conceptualization of equity highlights the relative importance of equal opportunity provision over outcome-based redistribution, but not necessarily the exclusion of the latter for the sake of the former.

Inequality traps

Based on this relatively modern notion of equity, it is possible to identify three ways that equity and development are complementary in Developing countries. The first of these ways touches on the notion of “inequality traps.” Inequality traps can be defined as the reproduction of economic, political and social inequalities “over time and across generations.”⁷ Existing political and economic inequalities in Developing countries systematically favor the interests of a relatively small elite group over the rest of the society. By the use of overt or covert power, the elite in Developing countries are able to influence the policymaking process more effectively despite their disadvantage in number. As the poor are likely to be much less involved in the political decision-making process, the vicious circle of underperformance continues.

The second way that equity and development relate to each other comes in the form of inefficient redistribution mechanisms. The institutional structures are tailored to benefit not the neediest in the society, but rather middle-class and upper middle-class citizens.⁸Hence, the influence of the more advantaged in the society further determines the shape of the institutional structure.

Finally, leveling the playing field does potentially affect the investment and innovation environment. A modern economy is inconceivable without an active investment environment. Inequality of opportunity prevents individuals like Nthabiseng from taking part in the modern economy and realizing their potential. Barred from entry, either through institutional mechanisms or mere negligence, individuals facing inequality of opportunity will not be able to enrich the environment of competition necessary for economic development. The relatively few and well-endowed rich will be less likely to feel any pressure to pursue innovation and investment opportunities. Competition, which is regarded as the major source of development, will not come about. As a result, the resulting environment is inimical to sustainable development and poverty reduction.

Implications

Several world religions endorse social justice, helping the poor, and equality as central principles in their teachings. Even though these principles may manifest themselves in fundamentally different ways, the basic idea remains the same. Christians are urged to love their neighbors as themselves; Buddhists are responsible for caring for the poor; one of the five pillars of Islam is zakat (almsgiving); and, the word for “charity” is the same as for “justice” in Hebrew.⁹ As a demonstration of this shared concern among world religions, the World Faiths Development Dialogue has issued a statement the essence of which asserts as follows: “All religions would see the extreme material poverty in the world today as a moral indictment to contemporary humanity and a breach of trust within the human family.”¹⁰ In addition to this poverty-reducing aspect of religions, it is easy to see how this recent understanding of equity can also be inferred from one of the fundamental tenets of all religions. Human dignity constitutes a shared and fundamental theological principle for world religions.¹¹ In order for human beings to reflect this dignity, the latent potential for perfection has to be provided with the right set of opportunities, and basic necessities such as health care, education, and nutrition. Otherwise, undeveloped individual potentials do run the risk of being wasted leading to both dishonoring human dignity and economic underdevelopment, as a social phenomenon.

In what preceded, I introduced a new perspective on economic development, a chronic problem among Developing countries. By making a distinction between equality of income and equality of opportunities, the presumed trade-off between equality and economic growth might be overcome. It is my hope that this new emphasis on equality and human development will allow billions of people living in dire conditions to reclaim their dignity as humans. Eventually, this emphasis on human development will result in economic development, long-anticipated in Developing countries.

A. Kadir Yildirim is a PhD candidate in political science at the Ohio State University. He can be reached at yildirim.10@osu.edu.

Notes

1. The story of Nthabiseng and Pieter is taken from World Development Report 2006 by World Bank.
2. Human Development is defined by the United Nations Development Programme as “the priority of human well-being, and aimed at ensuring and enlarging human choices which lead to equality of opportunities for all people in society and empowerment of people so that they participate in – and benefit from – the development process.” Education, health care, and quality of life are different aspects of human development. For reference, see: http://www.undp.org/rbec/nhdr/1996/georgia/glossary.htm
3. Bruce Moon and William Dixon. 1992. “Basic Needs and Growth-Welfare Trade-offs.” International Studies Quarterly. Vol. 36 (2).
4. World Development Report 2006: Equity and Development. Oxford University Press: New York.
5. John Rawls. 1971. A Theory of Justice. Cambridge, MA: Harvard University Press.
6. Amartya Sen. 1985. Commodities and Capabilities. Amsterdam: North-Holland.
7. World Development Report, p. 2.
8. Rudra, Nita. Who Really Gets Hurt? Globalization and the Race to the Bottom in Developing Countries Manuscript. Also, see World Development Report, p. 179, for a similar discussion.
9. World Development Report, p. 76.
10. http://www.wfdd.org.uk/, September 1999.
11. In a recent article in The Fountain, Halim Calis presents a compelling argument on human dignity in Islam and Christianity as a common ground for interfaith dialogue. See “Holy Sources of Human Dignity.” The Fountain, Issue 58, 2007.

In general, the most common approach in tissue engineering is to develop tools as needed. Physicians treat patients and define the requirements for a better cure. Then, biologists study the targeted problem and learn what the mechanism is that caused the failure. Later, chemists and materials scientists manufacture the tools needed to treat the problem. Finally, the tools are delivered to doctors to treat the patients. Thus, tissue engineering requires a good understanding of how body parts work and come into existence, and this involves precise and sensitive application. Precise, aware and regular study of the interactions involved in tissues and organs must be practiced by the researchers who are interested in developing techniques for the manufacture of potential body parts. One of the first scientific approaches used for tissue engineering is to simply inject the body with molecules, such as growth factors, which are known to promote organ formation.

The growth factors are naturally occurring proteins which are assigned for cell proliferation and differentiation. Different parts of the body require different types of growth factors to signal to the cells to multiply or to replace the cells which have died or have been damaged. For example, it has been discovered that bone morphogenic proteins are responsible for the beginning of bone cell reproduction. For someone with a fractured bone that can not heal on its own within a reasonable period of time, the injection of bone growth factors to the site can direct the body to where bone cells are needed to be produced to repair the fracture.

In more severe conditions, the body may not receive the signal only with a simple injection of the growth factors. In this case, there is a need for more intricate treatment. Another way to treat organ malfunction starts with the harvesting of cells from the patient. The harvested cells can be multiplied in an artificial scaffold to eventually be implanted into the wound site. Because cells inhabit a different world than we do, we need a way to speak their language. The artificial scaffold should provide everything a cell needs and be able to direct the targeted cells toward the desired purpose. Basic knowledge gained from biology can help us to design potential artificial environments for cells.

A critical challenge in tissue engineering is how to design and make the artificial scaffolds. The cells must be fed through the blood vessel and are grown in the scaffold by the body; the scaffold should be able to communicate with the cells and finally the scaffold should disappear when its mission has been completed. The best example of a perfect scaffold is the natural environment of the cells, the extracellular matrix (ECM). The ECM provides support and anchorage for the cells and regulates communication between cells. There are various biological signals found in the ECM that help cell survival. For example, proteins called collagens provide mechanical support for cells through adhesive proteins in the ECM and the handles on the cell surface, known as integrins. Cell adhesion is crucial for cell survival and proliferation. Growth factors are also found in the ECM for cell organization. Some growth factors promote blood vessel formation, which can provide nutrients for cells. Therefore, a simple artificial environment should include various biological signals found in the ECM.

Currently, there are natural and synthetic scaffolds that are being used to generate the optimal environment for cells. Natural polymers such as collagen, chitosan or glycosaminoglycans, and synthetic polymers, including polylactic acid, polyglycolic acid, polycaprolactone or self-assembled nanofibers, are some of the materials used or considered for scaffold production. Natural polymers can be obtained easily, however biological contamination is a concern since they are produced using components from animals or microorganisms. Synthetic polymers can usually avoid the problem of contamination. Sometimes the ability to process the polymers can be problematic. Researchers have developed self-assembled nanofibers to overcome the problems that arise with synthetic and natural polymers. These nanofibers are composed of small molecules which are programmed to come together under control and to form larger structures. The nanofibers in the solution can form a three-dimensional network and convert into a self-supporting gel which can encapsulate cells as an artificial scaffold. In general, small bioactive molecules can be conjugated to the self-assembled molecules or can be encapsulated in situ in the 3-D network of fibers.

One of the recent uses of tissue engineering is to replace tissue that has been damaged by cancer. Cancer surgery is one of the most challenging types of surgery in that the defective tissue must be reconstructed afterwards. Improvement in surgical technology gives the chance of transferring a tissue from different sites of the body but unfortunately most of the time it is not the same tissue, and does not have the same texture or function. Reconstructing a resected tongue or the feeding tube is possible with the use of skin from the leg or forearm. But this skin does not provide the normal mucosal function, so it does not enable taste or sense to be perceived in the same way nor does it produce mucus in the same way. Together with advances in tissue engineering surgeons have started using the tissue-engineered mucosa of patients to reconstruct the mouth and feeding passage defects, instead of using the skin from chest, leg or forearm skin. These clinical applications of tissue engineering are in their very early stages, but it would not be surprising if we were able to reconstruct a lost organ from a similar one in the future. It would be exciting to be able to replace the tongue of a tongue cancer patient with a brand new tongue grown from his/her own tissues produced in a laboratory. Tasting the same…sensing the same…moving and even articulating the same…instead of having a piece of meat from another part of the body…

Innovative and imaginative work which has been inspired by natural materials demonstrates how the treatment of organ malfunctions is feasible. Efforts in biotechnology to develop tissue-engineered products will benefit many people who are searching for a healthier life. Potentially, in the near future, tissue-engineered products will be more widely used to treat bone fractures, serious skin burns, spinal cord injuries, diabetes, and heart diseases. Before implanting the tissue-engineered products, it is vital that there be extensive testing of the materials to be used. Toxicology and efficacy studies should be performed on the materials to prevent damage to the original healthy cells, and the new cells and regenerated tissue must be compared to original healthy cells and tissue.

Mustafa Guler has a PhD in chemistry. He is currently a research associate at Northwestern University, Chicago, IL. Joseph Coreman is a medical doctor at the Ohio State University Medical College, Columbus, OH.

References

• Khariwala SS, Vivek PP, Lorenz RR, Esclamado RM, Wood B, Strome M, Alam DS. Swallowing outcomes after microvascular head and neck reconstruction: a prospective review of 191 cases. Laryngoscope. 2007 Aug; 117(8):1359-63.
• Sauerbier S, Gutwald R, Wiedmann-Al-Ahmad M, Lauer G, Schmelzeisen R. Clinical application of tissue-engineered transplants. Part I: mucosa. Clin Oral Implants Res. 2006 Dec; 17(6):625-32.
• Hotta T, Yokoo S, Terashi H, Komori T. Clinical and histopathological analysis of healing process of intraoral reconstruction with ex vivo produced oral mucosa equivalent. Kobe J Med Sci. 2007;53(1-2):1-14.
• Ratner, Buddy D. “Biomaterials Science – An Introduction to Materials in Medicine” Elsevier, 2004.
• Lanza, Robert P., Robert S. Langer, William L. Chick, “Principles of Tissue Engineering”, Academic Press, 1997.
• Alberts, Bruce, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, Peter Walter, “Molecular Biology of the Cell” Garland Science, 2002.

The second leading cause of death in the United States, after heart diseases, is cancer, claiming around half a million lives every year.(1) People today are concerned more than ever about cancer and its terrible consequences. However, in the light of recent scientific findings, a very different picture can be seen: In an environment with increasing carcinogens, it is actually surprising to find most populations are cancer-free. This is because our bodies are equipped with systems to prevent cancer formation.

Cancer research over the last two decades has shown that cancer is a disease of the genome.(2) Changes in the DNA, called mutations, disrupt the regular cellular networks that control a state of delicate balance. People are continuously exposed to varying amounts of chemicals that have been shown to cause mutations in the genome which may lead to cancer formation. Exposure to harmful chemicals can occur due to being in an environment where these agents are present in the food, air or water, and also due to our own metabolism which may produce these chemicals. It has been estimated that exposure to environmental chemical carcinogens may contribute significantly to the formation of the majority of human cancers.(3)

Even though some of the mutations caused by these agents hit cancer-critical genes, cancer does not immediately develop. Furthermore, cancer is mostly seen in old age, when many mutations have accumulated in the genome. The reason why we are protected from developing cancer, even though our DNA is under numerous types of attacks everyday, is that our cells are equipped with several lines of defense against cancer formation. These built-in defenses include DNA damage repair systems, external and internal controls of cell division rate, and the programmed death of cells. All of these defenses have been given to our cells in order to protect us from getting cancer. If we were not to have these defenses, cancer would be a daily occurrence for every one.

It is possible to say that a cell’s first defense against cancer is similar to the regular maintenance of a car. One has to replace the brake pads, change the oil, etc., so that the aging of the parts will not cause failure that may lead to an accident. Similarly, chemical carcinogens from environmental pollution, ultraviolet rays from the sun, radiation from various sources, etc. all cause multiple types of damage in the DNA molecule. Therefore, our cells and genome need maintenance as well. This function is carried out by groups of proteins called DNA repair complexes. DNA repair mechanisms have been designed to correct the DNA damage before it can lead to inheritable mutations.(4)

If the DNA damage repair systems are intact, most of the damages to the genome are dealt with before they can cause problems. We observe the extent of attacks that can damage the DNA on our genome in many types of cancer where the DNA repair mechanisms are known to have been inactivated. In these cancer cells, mutations accumulate at a very fast rate, leading to more aberrant behavior. Also, individuals with defective DNA repair systems are more susceptible to developing various types of cancer.(4,5) Therefore, the first line of defense given to our cells against cancer is the ability to check and correct the integrity of our genome.

Every cell type in our body has been designed to proliferate at a certain rate that is suitable for the function of those cells. For example, neurons or muscle cells almost never divide after reaching adulthood, whereas the epithelial cells lining the interior of the intestines or under the skin divide at a fast rate continuously throughout our lives. The rate of division of a cell is mainly controlled by extra-cellular cues, i.e. a normal cell doesn’t grow or divide unless it receives growth and proliferation signals from neighboring cells.

There is a safe rate at which a cell must divide – just as a car needs to be driven at a safe speed. The requirement of cells for external stimuli in order to grow and divide is like the car’s need for someone to step on the gas pedal in order to accelerate. Normal cells cannot grow without control as neighboring cells produce growth signals when they are necessary and stop producing them in a regulated manner. A good example of the control of cell proliferation rate is seen in the wound healing process. When there is a cut in the skin, the cells adjacent to the wound are stimulated to divide rapidly by signals given from the injured cells; they divide and close the wound as soon as possible. However, when there are no wounds, there is no signal to divide and the skin cells only divide at a very slow rate, just enough to replace dying cells; this is a much slower process than wound healing. Cancer cells, on the other hand, are known to produce their own growth signals and proliferate abnormally fast and in an uncontrolled manner.(6) Therefore, the environmental control of cell division is an important barrier against cancer formation.

Cancer cells cannot divide uncontrollably unless they are independent of the external stimuli to divide. However, cancer cells can produce their own growth and proliferation signals, so they are free from external constraints. But even then, all is not yet lost. This situation of uncontrolled and rapid cellular proliferation is like a car in which the accelerator has become jammed– the car accelerates continuously and an accident is impending. In this situation the way to prevent too much speed is to step on the brake of the car. Similarly, in a cell, there are a set of genes called tumor-suppressor genes, which are responsible for stopping cell division upon excessive growth stimuli.(7) These genes act like brakes in cell division and prevent further progression into a malignant state. In many cancers,(8) it has been shown that these genes have been inactivated. If the brakes of the car are functional, you can safely bring your car to a stop and fix the problem that caused the accelerator to jam. Similarly, if a cell starts to divide too rapidly, it can stop dividing and repair the damage that caused the uncontrolled growth. Therefore, tumor suppressor genes represent a third line of defense.

If all the previous safety valves fail, there is one more defense to cancer. A situation in which a cell with harmful mutations promotes its own proliferation and cannot abort the division process is similar to one where the accelerator of the car is jammed and the brakes don’t work. In this case, in order to prevent greater damage, one can choose to hit a wall or a tree to stop the car– this will total the car, but will prevent further damage to others. Similarly, if a cell begins to grow uncontrollably and can’t slow down its rate of division, a process called apoptosis, or programmed cell death is initiated. In apoptosis, the cellular DNA and cellular compartments, like lysozomes, Endoplasmic Reticulum, and Golgi are degraded, and the cell shrinks in size. In the end, the cell dies and is absorbed by neighboring normal tissue. Therefore, the programmed death of an aberrantly behaving cell is another way that the body is protected from cancer. As expected, in cancer cells defects in this last line of defense are observed as well.(9)

These four mechanisms, i.e. DNA repair, external/ internal cell division suppression, and programmed cell death, are only the ones that we are aware of at this time. In addition to these, there are multiple levels of other redundant safety checks. All these safety features work without our knowledge or will. Findings from cancer research show that the design of cells was carried out so intelligently that even the carcinogenic environment which we produce today was accounted for within the genes of the very first human being.

Notes

1. Cancer Statistics 2006. 2006, American Cancer Society.

2. Vogelstein, B. and K.W. Kinzler, “The multistep nature of cancer.” Trends Genet, 1993. 9(4): p. 138-41.

3. Wogan, G.N., et al., “Environmental and chemical carcinogenesis.” Semin Cancer Biol, 2004. 14(6): p. 473-86.

4. Dixon, K. and E. Kopras, “Genetic alterations and DNA repair in human carcinogenesis.” Semin Cancer Biol, 2004. 14(6): p. 441-8.

5. Jiricny, J., “The multifaceted mismatch-repair system.” Nat Rev Mol Cell Biol, 2006. 7(5): p. 335-46.

6. Brattain, M.G., et al., “Growth factor balance and tumor progression.” Curr Opin Oncol, 1994. 6(1): p. 77-81.

7. Hanahan, D. and R.A. Weinberg, “The hallmarks of cancer.” Cell, 2000. 100(1): p. 57-70.

8. Coleman, W.B. and G.J. Tsongalis, “Molecular mechanisms of human carcinogenesis.” Exs, 2006(96): p. 321-49.

9. Dlamini, Z., Z. Mbita, and T. Ledwaba, “Can targeting apoptosis resolve the cancer saga?” Future Oncol, 2005. 1(3): p. 339-49.

The word ‘robot’ was first used in the 1922 play R.U.R. by the Czech playwright Karel Capek: the title is an acronym for Rossum’s Universal Robots which become so sophisticated that they take over the world. ‘Robot’ is compounded from the Czech words ‘robota’ or work, and ‘robotnik’ or serf (Capek. 1923).

The use of industrial robots, first clearly identified in the 1960s, along with computer aided design (CAD) and computed aided manufacturing (CAM) systems, characterizes the latest trends in the automation of the manufacturing process (Roth, 1983). These technologies arc leading industrial automation through another transition, the scope of which is still unknown.

Growth of the robotics market has slowed compared to the early 1980s. The use of industrial robots is at present concentrated in rather simple, repetitive tasks which do not to require high precision. However, manufacturing market analysis predicts that early next century industrial robots will become increasingly viable in applications which require more precision and sensory sophistication such as assembly tasks. The automotive industry, where robots have been economically justified since the 1970s, will continue to be the leading user. However, the major growth of the US robot population will occur in non-automotive industries.

2. Robot classes and characteristics

Robots can be classified in many ways. To establish a generic classification system, we shall refer to dimensions or degrees of freedom or DOF.

The DOF of a mechanical system refers to the number of physical axes through which motion can occur. In robotics, DOF can often be equated with the number of joints in the robot.

Typical present-day industrial robots have from one to six-DOF, although more are certainly possible. For example, a wrist can be made more flexible by adding rotation to the twisting already in that joint. Similarly, a fourth DOF can be added to the shoulder, where the arm joins the base to allow additional rotation of the arm. Industrial robots are also classified by the mechanical configuration of the individual elements of the arm and actuators. Theses classifications are: rectangular class (X,Y,Z): cylindrical class (R,?,Z): spherical class (R,?,?); and jointed class (?1,?1,?). This classification begins with simple movements in a rectangular co-ordinate system such as the x-y co-ordinate system.

3. World’s robot population

More than 610.000 industrial robots are now at work according to a new annual publication by the secretariat of the United Nations Economic Commission for Europe (UN/ECE) and the International Federation of Robotics (IFR).

The world’s robot population grew by about 6% in 1993 compared with 8% the year before. These growth rates fall significantly short of those of 16-23% recorded in the booming late 1980s and early 1990s. However, in view of the deep recession which commenced at the end of 1990 in robot-using countries and resulted in large reductions in investment and industrial employment, growth in the robot stock of 6%-8% is still quite impressive. 

Japan accounts for more than half of the world robot stock. However, the net increase in Japanese robot stock fell sharply in both 1992 and 1993. In 1993, the net increase in the robot stock was only about a third of the record year 1990, underscoring the depth of the Japanese recession.

With 325 robots for every 10.000 persons employed in manufacturing, Japan has by far the world’s highest robot density followed by Singapore with 109, Sweden with 73, Italy with 70 and Germany with 62. As a result of falling employment in the manufacturing industry in 1992-1993, robot density increased rapidly in many countries even though the robot stock increased only modestly.

In most countries, welding is the predominant application area for robots, particularly for major motor vehicle producing countries, accounting for more than 20% of the total robot stock. In a few countries machining was the largest application area. Assembly was the largest application area in Japan, accounting for 40% of the total stock of robots. It is worth noting that in Japan assembly accounted for 50% of the net increase in stock while welding only had a share of 9%.After a solid recovery in 1994, the robot market is forecast to boom in the period up to 1998. Based on macroeconomics forecast of the development of world economics the UN/ECE and IFR forecast that the world stock of industrial robots will increase from some 610,000 units at the end of 1993 to over 830.000 units at the end of 1997. As the number of personnel employed in industry is falling, the density of robots measured as the number of robots per 10.000 workers will continue to surge. In terms of units, shipments are estimated to increase from about 54.000 units in 1993 to over 103,000 units in 1997.

While the robot market was expected to be somewhat hesitant in Japan in 1994 and 1995, it was expected to boom in the United States, Western Europe and the dynamic Asian economies. If growth and world trade gain momentum as predicted from 1995, the prospects for the robotics business seem extremely bright.

The potential for expansion of robotics is enormous. If other industrialized countries were to approach the robot densities of Japan and if industry in general were to reach only half the robot density of the motor vehicle sector, the robot stock would increase manifold, and this is not counting the potential for robots in the service industries. The following example gives an illustration of the potential: if industry in France and the United Kingdom were to achieve a robot density half that of the motor vehicle industry in those countries, the robot stock would more than double; if it reached half the density of the Japanese motor vehicle industry, the robot stock in those countries would increase more than 20 times.

4. Summary

The emphasis in this article has been on industrial robots and techniques currently used in that environment. The future of robotics depends on improvements in many technologies to reduce cost and increase the range of performance so that robots become effective in more environments. These technologies include motors, actuators, contact sensors, non contact sensors, mechanisms, lubrication, electronics, computers and artificial intelligence.

References 

• CAPEK. K. (1923) R.U.R.. Samuel French. London.
• ROTH. B. (1983) Principles of Automation, in Future Directions in Manufacturing Technology, based on the Unilever Research and Engineering Division Symposium held at Port Sunlight, April 1983. Unilever Research. UK