Original Article: Cranford, S.W. et al., Nature 482, 72 (2012).

Spider silk has been a symbol of durability and strength, but the role the design of a web plays or contributes to the strength was unknown. Researchers from Massachusetts Institute of Technology discovered that the impressive design of web and the feature of silk allow spiders to build a super-strong web under different levels of stress. The response of spider silk subjected to load was studied. They studied webs of a variety of species, including European garden spiders and orb weavers, and combined their experiments with correlated web models. At low stress, silk threads soften and extend that result in retaining web structure. At high stress, the silk threads extend and the most stretched ones break. The strength of the silk and the geometry of the web allow only one or two threads being broken under strain. Therefore, the break in the web is minimized and prevents destruction of the whole web. The localized web damage can be repaired by the spider and therefore a requirement for rebuilding the web completely is eliminated. This study shows that spider silk web is very stable even under hurricane winds. This research gives an idea to engineers to build a system that will fail only at small parts of the system under certain stress. Therefore, the system will continue to work just after repairing the destroyed parts of the system. Otherwise, the whole system may be destroyed under potential load and will have to be rebuilt. For example, when a building is exposed to large mechanical stress such as an earthquake, it may be destroyed as a whole and become dysfunctional. Applications on such systems require further research in engineering to achieve structures as stable as a spider’s web.

2- Benefits of Exercise Through a Protein

Original article: Bostrom, P. et al., Nature 481, 463 (2012).

Exercise has a number of beneficial effects in human health such as increasing cardiovascular, respiratory and metabolic capacity. Scientists at Harvard Medical School have discovered a muscle hormone, Irisin, which may be responsible for the many beneficial effects of exercise. Irisin secreted from muscle after exercise and act on white adipose tissue that stores energy. Excessive amounts of white fat cells contribute to many pathologic effects of obesity and diabetes. Irisin, however, converts white fat into the more beneficial and metabolically active brown fat, which burns more calories and produce heat instead of energy. It helps to prevent excessive glucose and fatty acid accumulation in the body. The researchers demonstrated that mildly increased Irisin levels in the blood cause an increase in energy expenditure in mice with no changes in movement or food intake. It also reduces body weight and improves glucose tolerance and obesity induced insulin resistance. This research suggests that Irisin can be a new therapeutic target in human metabolic diseases treatment. Also it could help people lose weight and fight against obesity induced problems such as diabetes and hypertension.

3- New Generation Vaccines with High Efficacy

Original Article: Avci F.Y. et al., Nature Medicine 17, 1602 (December 2011).

Most pathogenic bacteria contain complex carbohydrate structures on their surfaces. These carbohydrates are called capsular polysaccharides. “Glycoconjugate” vaccines are prepared by chemical conjugation of capsular polysaccharides with proteins. This method is the standard design for many vaccines that protect us against common diseases such as pneumonia and meningitis. One drawback with these vaccines is their limited efficacy in populations such as the elderly, children and patients with compromised immune systems. Researchers at Harvard Medical School and Rockefeller University have designed and synthesized a vaccine that is about 100 times more potent than traditional vaccines available today. Until now, the scientific community believed that the body’s professional immune cells, called T-cells, were only able to recognize vaccine’s protein molecules to generate an immune response. However, after studying how glycoconjugate vaccines stimulate immune response, the researchers found that T-cells are also able to recognize the carbohydrate molecules. In a series of elegant experiments, they demonstrated that there is a repertoire of T-cells that can recognize the carbohydrate portion of a glycoconjugate vaccine, and that these T-cells stimulate antibody producing B-cells to generate high affinity antibodies against the carbohydrates. Based on the knowledge obtained from this mechanistic study, researchers have designed a new-generation glycoconjugate vaccine and showed that this new vaccine was about 100 times more immunogenic than a vaccine made by traditional methods.

4- Producing Fuel from Waste with Bacteria

Original Article: Bokinsky, G. et al., PNAS 108, 19949 (December 2011).

It turns out, the secret for alternative source for oil might be hidden in a very common bacterium and plant, E coli and switch grass. As the world’s natural resources are quickly exhausted by humans, new energy sources or alternative energy production methods are needed. One popular way for addressing this question is promoting biofuels. Most of the biofuel source is in ethanol form, often produced from sugar that is extracted from sugarcane and corn. However the consuming of main food sources for energy sources begs a question: What if one day feeding the machines with our food sources makes food scarce? Another concern is that many countries are not using ethanol as an energy source. All these led researchers to pursue another idea: Instead of using food sources as precursor for ethanol, non-food biomass or bio-waste can be converted to precursors for biofuels by utilizing the cellulose or hemicellulose as a starting material. Human body cannot digest cellulose. Hence, cellulose is a bio-waste, which can be broken down into sugar using a mixture of enzymes and subsequently can be used for gasoline production. The enzymes for this procedure can be produced by bacteria in massive amounts. To this end, researchers genetically engineered Ecoli bacteria to consume large amount of cellulose from switch grass and convert it to sugar. Scientists achieved to produce different precursors for different fuels, including gasoline, diesel or jet fuel with bacteria. These are big steps in turning bio-waste into fuels. Imagine one day your plane will be powered with a hay of switch grass and a bottle of bacteria. Next time when you fly over a field of switch grass, you might actually be seeing the next oil well.

The point of this article is not who hates who. Rather, we want to learn why people become angry with others who have different skin colors,

religions, or thoughts. This nightmare, known as racism, has been the source of great and frequent violence throughout history.

Who Was the First Racist?

The first racist was Satan, for he hated Adam. According to Qur’an 17:61: All angels prostrated [before Adam], except Iblis [Satan]. He asked: Shall I prostrate to one whom You made from clay? What was Satan’s biggest mistake? Instead of accepting the reality of diversity in creation, he sought to justify his rejection of Adam. He assumed and asserted that he was nobler than Adam. He did not ponder who decides everyone’s color, nation, and social environment, but justified his racist superiority: [God] asked: Why did you not prostrate when I commanded you? [Satan] replied: I am nobler than him. You created me from fire, but You created him from clay (7:12).

Since this early racist dialectic, all racist groups and their followers have used similar arguments to justify their beliefs and prove that they are the best. The result of such an effort has been a very bloody history.

We are living in a period of rapid change. Due to the global media, these changes affect everyone. Hate organizations use the media to expand their reach in totally new ways. Of course, this is not new: In Italy, in 1922, Benito Mussolini understood the power of the brand-new medium, radio, and he began to use it as soon as it was electronically possible in his country. Some years later he was quoted as saying, ˜If it weren’t for radio, I wouldn’t have the power over the Italian people that I have.(2)

In recent years, the Internet has become a major tool for extremist propaganda. Time columnist John Cloud makes a significant point:

He is absolutely right, for creating hate-filled Web sites is easier and cheaper than taking risks, such as public demonstrations and protests. Don Black, founder of a famous racist Web site, learned in jail how to use the Internet to spread his message. He started a Web site, which at last count had been visited by over 3 million people. It even has sections for women and children.

How Do Such Sites Affect People?

A recent race crime horrified the nation. On June 7, 1998, William King and his friends kidnapped James Byrd, an African-American, tied him to their truck, and dragged him to his death. How can a person become a racist murder? While covering the story, the American media found several reasons, among them that a hate group had agitated King while he was in jail. The Christian Science Monitor interviewed Clara Byrd-Taylor, Byrd’s sister, to get insight into King’s personality: After the dragging death of Texan James Byrd, his sister decided that he would not die in vain. She set out to discover what could have nurtured the hate that killed her brother. She found it on the Internet. ˜Prior to the death of my brother,’ Clara Byrd-Taylor says, ˜I had very little knowledge about the hate sites and what was happening with the hate groups around the world. I had heard isolated incidents, but I had not put all those things together.'(4) There are now over 600 hate Web sites, most of them targeted specifically at young people. The Internet and rock music are two key attractions for youth. CD and Web sites have presented young people with music mixed with advocacy of violence and racial separation Resistance Records, in Detroit, identified as a neo-Nazi music label, sells about 50,000 albums a year through its Web site.(5) Why are youths chosen as targets? Nowadays, more people feel lonely even though they live and interact with people all the time, such as in the workplace. But sharing social and moral values with some communities, like family, has been forgotten. People are losing themselves and, as a result, seeking a new identity that might solve their individual and social crises. Many young people feel isolated by the social structure, and so face an identity crisis. They feel alone, insecure, and abandoned. Music about violence offers messages that highlight the importance of rebelling against social discipline and authority. Being a part of the group and against others is a way to obtain a new social identity for many young people, who see everything in black and white. This is a very complicated problem without a clear solution. Many academic researchers and human rights groups are trying to learn how to overcome hate propaganda on the media. For instance, the Southern Poverty Law Center declared 10 ways to fight racism. They are as follows(6):

Act. Apathy is interpreted as acceptance.

Unite. Join those who oppose hate and work to eliminate it.

Support the Victims. Let victims know that you care, and report any hate directed toward you or people you know.

Do Your Homework. Learn how to identify hate groups and spread this knowledge to others.

Create an Alternative. Find another outlet for anger and frustration, and capitalize on people’s desire to do something

Speak Up. Expose and denounce hate wherever and whenever you can.

Lobby Leaders. Persuade political, business, and community leaders to take a stand against hate in the interest of their reputations and businesses.

Look Long Range.Create a bias response team and celebrate your community’s diversity and harmony.

Teach Tolerance. Bias is learned early, usually at home. Sponsor an I have a dream contest. Target youths who may be tempted by skinheads or other hate groups.

Dig Deeper. Study divisive issues so that you can determine your own prejudices, and then work to eliminate social prejudice.

Defining Censorship

One of the most contentious media-related issues is defining censorship. Governments are responsible for protecting their citizens from racist groups and propaganda. For instance, Canada and Germany are trying to catch people who use the media, including personal Web sites, to spread hate. But there is still one vital question that must be answered: Who defines protecting the people, especially the young, and protecting the freedom of speech? Prohibiting such speech is not the answer, because governments have abused this authority throughout history. Besides, modern technology and its products almost have eliminated the importance of physical borders as tools for governmental control.

What You Can Do

If you are involved in education or business, work to get your employers to focus on cultural diversity as a valuable human resource. Schools are many children’s first direct exposure to different cultures and peoples. The business sector often brings people who otherwise would not meet each other into close contact, thereby dispelling stereotypes. If handled correctly, deep biases can be destroyed in both children and adults. In addition, the importance of peace must be taught and reinforced in the home, school, workplace, and everywhere else. Create your own anti-hate Web site. Spread the information provided by such anti-hate organization Web sites as:

www.angelfire.com/on2/EvasGarden/AntiHate.html

http://earnestman.tripod.com/forewarned.htm,www.kcmetro.cc.mo.us/multicultural/pages/anti.htm,

and

http://users.westnet.gr/~cgian/hatred1_frame.html.

Subscribe to their publications, donate money or time, and participate in their activities whenever possible. Protest all radio programs and music that encourage this nightmare of modern times. Explain to your children why you oppose their listening to such programs or music. Sponsors and producers are not immune to public outcry and negative publicity. Remind the mainstream media that it has the vital responsibility of showing its audience how to live together without hate. If religious or racial discrimination are tolerated or even encouraged, the media only reinforces negative or distorted images and racism. Establish or join coalitions devoted to fighting hate messages. Explain to others that you do so in order to create a better future for everyone by trying to prevent the racist nightmare from destroying our good dreams for the future.

Footnotes

1. The Southern Poverty Law Center, Ten Ways to Fight Hate: A Community Response Guide. Online at: www.splcenter.org.
2. Robert L. Hilliard and Michael C. Keith, Waves of Rancor: Turning in the Radical Right (M. E. Sharpe: 1999), 20.
3. John Cloud, Trading White Sheets for Pinstripes, Time Magazine (8 March 1999).
4. Gloria Goodale, HBO Exposes Hate Groups in Cyberspace, The Christian Science Monitor (20 October 2000), 20.
5. Hilliard and Keith, Waves of Rancor, 55.
6. The full text is available online at: www.splcenter.org/intelligenceproject/ip-index.html.

But sometimes messages can lead to malicious results. Some carry viruses, defined as unwanted and sometimes harmful computer codes. Others are hijacked and spill their secrets without a fight, or seem to come from friends who “decided” to send you false news.

Given today’s reliance on e-mail, any security gap is a problem. Fortunately, such gaps are filled easily and can keep important e-mail safe and secret.

Is E-mail Privacy an Illusion?

The most common fear is prying eyes. Just as standard mail may not be private, e-mail is not entirely private, for it is easy to intercept e-mail messages. However, the risk of this occurring is often overstated.

Surveys show that many employers occasionally read employees’ e-mail. If the messages are on company-owned computers, such “snooping” is legal. If you send and receive e-mail on your own computer, you will face a similar problem: hackers. You cannot ignore the small chance of nosy hackers at servers along the way. Even worse, it is easy to make e-mail look like it came from someone else.

How can your e-mail privacy be protected? Fortunately, suitable tools are available. One is encryption, which prevents any message modification or disclosure. Digital signatures can be used for authentication purposes. While these may seem to aggravate the problem, they are proper steps to take if you are concerned about your e-mail’s privacy. Reliably identifying the message’s sender is even mentioned in the Holy Books, as in: O believers. If a wicked person comes to you with news, ascertain the truth, lest you harm people unwittingly and afterwards become full of repentance for what you have done (Qur’an 49:6).

Many other solutions, most of them free, also are available. For example Microsoft’s Outlook, the leading e-mail program, includes several built-in security features to protect your sent e-mail. Outlook can “digitally sign” messages with a special code to show that the message is from you, and also verify the sender’s signature. Second, you can encrypt messages and attachments to ensure privacy.

To sign or encrypt messages with such e-mail programs as Outlook, you need a digital ID (also known as a certificate or key). Digital IDs consist of a public key and private key. The private key is stored on your machine and is never sent to anyone. You can e-mail the public key to correspondents, or they can access it from a central server. When you send a signed message, your private key generates a code that only your public key can decode. Thus your public key verifies that you sent the message with your private key. When you send an encrypted message, you use their public key to encrypt it so that only their private key can decrypt it. If you follow this procedure, only the recipient with the correct private key will be able to read the message.

Digital IDs are available from such third-party companies as VeriSign. Once an ID has been imported, you can use the features on the Security tab in your e-mail program’s Options dialog box to establish a standard security procedure. Alternatively, individual users can download a free program based on the Pretty Good Privacy (PGP) standard for noncommercial use. PGP integrates itself with several e-mail programs and allows users to generate an ID for signing and encrypting e-mail or files. PGP also works with Web-based e-mail systems by allowing you to select text in any program and then sign or encrypt it.

Encryption keep messages secret. Even people sending e-mail at work can count on a PGP-type system to keep unwanted readers locked out, as long as both sender and recipient encrypt.

Things to Remember

Keep Passwords Secret: Web-based e-mail, such as Yahoo! Mail or Hotmail, presents another security concern: Subscribers can use any computer to check their messages. User IDs and passwords protect unauthorized access. But going somewhere without logging off lets someone else read your e-mail and send e-mail under your name. To avoid this, Yahoo! Mail or Hotmail automatically clear sensitive information from the browser’s cache when you log off. In addition, after you log off someone else cannot log on by clicking the back button.

Another strategy is to choose an unusual password and keep it secret. A simple e-mail password is easy to remember-and easy to crack. Many password cracking applications are online, and most use a dictionary of common words to search for your password. Your best bet is to use an alphanumeric password.

E-mail Viruses: New viruses, some of them quite harmful, pop up almost daily. One of the fastest ways to spread them is via e-mail. Recent examples are the Melissa and the so-called “I love you” viruses, which could copy and mail themselves to the first 50 people in your Outlook address book. To avoid this, learn the basic limitations of viruses. Receiving, opening, or reading an e-mail message will not infect your system. Viruses are not that wily yet, so you can open the messages. However, be careful about any attachments. Attachments are usually displayed as file icons at the message’s bottom or perhaps as hyperlinks that you need to download. Opening an attachment can allow a virus to escape and infect your system.

Some attached files are more virus-friendly than others. Watch out for files with .exe .com, and .bat extensions, for they can contain viruses. The fastest growing category of viruses today ride Microsoft Office Document (.doc) files as macros, executable files that record common keyboard and mouse actions to a single key with word processing, spreadsheet, and other documents.

One way to protect your computer is not to open attachments from strangers. A better and easier solution is to get an antivirus program that scans attachments before they can run. Such programs can hunt continuously in the background for macro viruses, as well as for the more traditional executable foes. Such virus-fighter sites as McAfee or Symantec allow you download a free demonstration version of their leading programs. Virus checkers cannot keep up with new viruses, so it is still smart not to open attachments from unidentified sources. Beware of an attachment that appears out of nowhere, even if you have loaded a virus program.

Misleading Links: Another threat is hyperlinks to odd Web sites. Many e-mail programs allow users to send Web links within a message so that recipients can click and begin loading the page in their browser. However, Web pages can contain scripts (a sequence of executable commands) designed to weasel through the browser’s security measures and infect your computer with virus-like programs. This is more a matter of browser security than e-mail security. Although you probably will not encounter a Web page sophisticated enough to take advantage of browser security problems, you should be prepared by ensuring that your browser’s security options are set appropriately. Also, keep your browser current.

You ‘ve Got E-mail: Although most security problems could strike anyone, most of us do not need to turn e-mail habits into something out of a spy novel. Just be aware of the possibilities and take a few steps to see that your e-mail is protected.

Try not to create e-mail security holes. Almost everyone sometimes sends an e-mail message to a wrong address. When addresses are no more than initials, numbers, and meaningless gib berish, this is easy. Often the results are slightly embarrassing-sometimes almost catastrophic.

Consider the case of the Illinois man who left Chicago’s snow-filled streets for a Florida vacation. His wife was on a business trip, and was planning to meet him there the next day. He sent her a quick e-mail upon reaching the hotel. Unfortunately, he missed one letter and his note reached the elderly wife of a preacher who had died the day before. When she checked her e-mail, she took one look at the monitor, screamed, and fainted. Her family rushed in and saw this note on the screen:

To My Dear Wife:

Just got checked in. Everything prepared for your arrival tomorrow.

Your Loving Husband

PS. Sure is hot down here.

References 

• http://email.about.com/internet/email/.
• www.emailtoday.com.
• www.lv.psu.edu/ojj/collectn/humor/dead-email.html.
• www.macafee.com.
• www.messagingonline.com/mt/html/feature031400.html.
• www.pgp.com/.
• www.publicdoman.com/email.html.
• www.smartcomputing.com/email.asp?emid-11018.
• www.symantec.com.
• www. timrichardson.net/misc/security.html.
• www.verisign.com/client/index.html. 

The Internet is a whole new world for everyone. If your children are not online, they probably will soon be joining the 10 million children already using the Internet.

What Is on the Internet?

Basically, the Internet is a great place for children. The good news is that it offers them educational and rewarding experiences, and that its effective use just might improve their school performance.

There are some disadvantages as well, such as inaccurate information and various inappropriate and uncomfortable information areas. Families and teachers should be aware of this potential problem. Just as parents do not allow their children to wonder alone in unknown territory, they should not allow them to interact on the Internet without parental guidance and supervision.

If parents worry that their children know more about the Internet and computers than they do, they can use this as an opportunity to have their children teach them about the Internet, such as where they like to go and what they like to do. Encourage children to talk about what is good and not-so-good about their Internet experience.

What Are the Risks?

Different Internet tools (e.g., chat, instant messaging, e-mail, news groups, and Web page) offer different kinds of risks and benefits.

Statistically, probably the greatest risk is that children will encounter mean or very unpleasant people in chat areas and news groups. Another risk is that they will spend a lot of time in areas that are not very productive. Other risks might be:

Loss of privacy (legal and financial, password, credit card number and private information)

Getting into online fights

Making threats and breaking the law

Viewing inappropriate material

Getting inaccurate information

Putting people in danger

Getting into drugs, alcohol, tobacco and other dangerous substances

Gambling and other inappropriate behavior.

What Parents Can Do

Keeping children safe on the Internet is everyone’s job. Parents must talk with their children about inappropriate behavior and stay in close touch as their children explore the Internet. By taking responsibility for children’s online computer use, parents can minimize any potential risks. Here are some suggestions:

Spend time online with your children. Your involvement is the best insurance of your children’s safety.

Teach children not to give out personal information (i.e., name, address, school name or address), especially in chat rooms and on bulletin boards.

Share your children’s e-mail account and password.

Teach them not to plan a face-to-face meeting with online acquaintances.

Keep the computer in the family area to better monitor their activity.

Spend time online with your children regularly to learn about their interests and activities.

Teach them how to end any uncomfortable or scary online experience by pressing the back key

Establish an atmosphere of trust and understanding by not blaming them for uncomfortable online experiences.

Discuss the difference between advertising and educational or entertaining content. Show your children examples each.

Tell them not to respond to offensive or dangerous e-mail, chat requests, or communications, and to leave if a Web site makes them uncomfortable.

Tell them to show you anything they receive that makes them uncomfortable.

Remember that anything you read online may not be true.

Explain that people in chat rooms are not always who they say they are.

If you become worried that your children in danger, contact the authorities.

Some Safety Tips to Help Children Online

Do not give out personal information (i.e., last name, phone number, credit card number, address, where you go to school, parent’s work address/phone number) without your parent’s permission.

Tell your parents right away if you come across anything that makes you uncomfortable.

Never send your picture or anything else without first asking your parents.

Never agree to get together with an online friend, without your parent’s permission. Meeting such people is usually a really bad idea. How people are in real life can be very different from how they are online. If you decide to do it anyway, be sure that it is in a public place and bring your parents along.

Do not open up e-mails, files, unknown attachments, or Web pages that you get from people that you do not know or trust.

Always follow your family’s rules for the Internet

Remember that honesty is the best policy. Not everyone believes this, however, so watch yourself when you are in cyberspace. Remember that since you cannot see or hear the other person, it is for a 40-year-old man to present himself as a 12-year-old girl.

Avoid chat rooms or discussion areas that look sketchy or provocative, and do not let people online trick you into thinking of them as real-life friends if you have never met them in person. Also, avoid online fights, because if you are looking for trouble on the Internet you will find it, and things can get out of hand very quickly.

The Internet, the World Wide Web, the information superhighway, and cyberspace describe the newest and most innovative and exciting learning tool of recent years. Remember that it is not the technology, but how it is used, that makes a difference.

Spending time online with your children is one of the best ways to learn and teach responsibility, good conduct, and values that are important to you. Ask your children to share their favorite Web sites and what they like about them. Work with them to discover Web sites that will help them with their homework, hobbies, and other special interests. Also, teach your children to be wise consumers in cyberspace. Not everything they see or hear may be true. Some sites may be trying to sell them something.

The vast majority of Internet sites are perfectly safe. But like the real world, the virtual world contains sites with sexual, violent, and other content that may not be appropriate for children. Since different families have different standards, it is important that parents establish clear Internet guidelines for their children.

If you have a home computer, several software programs are available to block objectionable Web sites. Even if filters were 100 percent effective, however, this software is no substitute for parental guidance. We strongly recommend that you supervise your children’s Internet use, and that you teach them how to make informed choices

References

• CyberAngels, Internet Safety Organization: http://www.cyberangels.org.
• Internet Use Survey: http://www.cyberdialogue. com/products/isg/aius/index.html.
• Safeguarding Our Children United Mothers: http://www.soc-um.org/.
• SafeKids: http://www.safekids.com/.

Yet, how can the Web be used for something more than surfing, chatting, making money, or wasting time? Can it provide an environment for learning? Can it be used with other educational technologies? What pedagogical possibilities do these technologies bring to schools, teachers, and students? In this article, I discuss this aspect of Internet.

One of the more explosive growth areas of the Web is distance learning. Web-based distance courses can run the range from text-based, e-mail, correspondence courses to full-blown interactive multimedia presentations. The vast majority of courses more closely resemble the text-based model, while many offerings use video, audio, and even some interactivity. Of particular interest is the newer interactive multimedia technologies found on the Web, such as Java, VRML, Shockwave, and others.

Several sites offer distance-learning offerings. The World Lecture Hall (www.utexas.edu/world/lecture/) offers hundreds of courses from universities all over the world, many with multimedia components. Java and VRML applets used in education are featured at www.gamelan.com. The Internet University (www.caso.com and www.internet-university.com) offers more than 500 courses. Other exemplary sites include San Francisco State University’s “Introduction to Multimedia” course, which features excellent design, interactive multimedia, graphics, streaming audio, and chat features (www.cel.sfsu.edu/MSP/msp.html). Also there are many homepages that offer free online courses, like www.learn.com and www.free-ed.net.

Educational Uses of the Internet

The following is a list of different educational uses of Internet. This is not exclusive, but rather a starting point.

Communication: Educators and students use the Internet to communicate when they exchange e-mail, contribute to electronic discussions groups, participate in Internet Relay Chat (“chat rooms”), and use video conferencing. These tools allow Internet users to send and receive messages from one or more people at the same time. The message may include words, pictures, illustrations, sounds, or movies (Education and the Internet 1996).

Collaborative Learning: Collaborative learning involves communication as well as individuals working in a cooperative team (Erkens & Kanselaar 1995). Team members share a common task and/or project. Collaborative projects may be student-based, for example, student-to-student and classroom-to-classroom projects that rely on teamwork established by teachers from different classrooms. Teacher-to-teacher and teacher-to-expert projects provide additional assistance and create a collaborative environment (Story 1996).

Resource Sharing and Information Gathering: Resource sharing consists of publishing information on the Internet for others to view and use. For educators, this includes lesson plans, learner activities, research papers, articles, newsletters, announcements, and school policies. The Web can serve as a gateway to the Internet’s vast resources. Educators and students use the Internet to solve problems, gain knowledge, and research almost any topic (Edwards, Havriluk, and Roblyer 1997).

Presentation Medium: Educators can use electronic presentation aids rather than overhead transparencies. For electronic presentations, users need a personal computer, presentation software (e.g., Adobe Persuasion, ClarisWorks Slideshow, Microsoft PowerPoint), and a projector. Software, hardware, and/or HTML scripting allows electronic presentation aids to be viewed via the Internet.

Interacting with Web Applications: With the Web’s multimedia capabilities, Web pages are being developed in such a way that users can input data and receive an output or a product. Search engines and dictionaries are examples of such interaction. Internet users can obtain e-mail addresses, interact with “live” animation, take virtual museum tours, locate an individual’s phone numbers, play games, and create their own Web pages. Feedback and assessment can be used to monitor student progress, control the learning pace, and evaluate teaching strategies. Using HTML Forms is a simple but powerful way to collect student feedback and control it to improve teaching. Forms collect data from students using Web-based course materials. Student feedback provides instructors an informed evaluation of their teaching. By using this evaluation method, instructors can get immediate feedback on course material, teaching style, and student progress. After this, they can make the necessary adjustments.

Interactive Multimedia Technologies

Every day Netscape, Microsoft, or another company announces an exciting new piece of technology that will deliver audio, animation, 3-D graphics, or allow one to wander through virtual spaces on the Web for free. Some of these are Live Audio, Shockwave, Java, Virtual Reality Modeling Language (VRML), Active X, and QuickTime Video.

What is new about such technologies? Physics teachers using Java created an applet for projectile motion that allows users to set the launch angle and coefficient of linear air resistance.

It then animates the body’s trajectory and calculates some of its properties numerically. (http://www3.adnc.com/~topquark/fun/applets.html.) What’s new and fascinating about such applets is that they offer hard-to-do simulations of physical events, are free, can be demonstrated on several computer operating systems, are highly interactive, and can be accessed at any time by anyone in the world with an Internet connection.

What would an interactive multimedia course module delivered over the Web look like? Physics teachers could videotape real-world phenomena depicting certain laws of physics, for example, the Ferris wheel and the “whip” for circular motion. They could supplement the video with audio lecture material, allow students to manipulate variables in a Java program, use VRML to create 3-D walk-through virtual models of how the laws of projectile motion apply, animate the behavior of balls on a track, conduct a synchronous two-way conversation with one student or the entire class via chat lines, correspond with individual students asynchronously via e-mail, and then quiz and grade students using online interactive exams.

Are there other reasons for using multimedia in teaching? The power of multimedia to impact learning positively can be seen in physics. Laws of physics that run counter to students’ commonsense notions of how the world works provide a stimulating catalyst for further investigation. In “The Initial Knowledge State of College Physics Students” (Journal of Physics 1986), I. A. Halloun and D. Hestenes demonstrated that freshman physics students’ intuitive notions of the behavior of a ball leaving a track are often contrary to the laws of circular motion, a major topic in freshman physics.

Other research indicates that these misconceptions may be overcome through video and animation. In one experiment conducted at the University of Massachusetts, the path of a ball on a circled track was videotaped. A segment of the track then was removed, and another video segment captured the ball’s path as it was about to leave the track. When queried at this point as to where the ball would go next, many students get stuck: their instinctive senses tell them it will go off in an upward path or a downward, not the straight-ahead path that it actually takes. A third video segment showed the actual straight-lined path of the ball leaving the track. An animation done in Director and then put on the Web with Shockwave showed that a circle is really composed of an infinite number of straight lines, and that when the ball hits one of them it goes off in a straight line. This straight-line path is, in fact, counterintuitive to many students. Using these multimedia supplements to regular course materials could improve test grades significantly. Web-based course materials are being used extensively to provide supplementary as well as standalone instruction in educational settings. One of the Web’s most powerful elements is its ability to engage learners in an interactive format. Although many technologies allow teachers to develop interactive Web course materials and receive student feedback, many continue to use the Web only for distributing static documents. This severely limits its potential to improve the teaching-learning process. Most education Web sites provide such basic course information as syllabus, schedule, announcements, and reading lists. Others include synchronous or asynchronous communication, online testing, discussion groups, conferences, bulletin boards, and streaming audio and video. These materials are available for courses that meet in classrooms regularly and use Web materials as supplementary tools, as well as for courses delivered entirely over the Web and without any traditional classroom meetings.

Web Interactivity

Web interactivity helps engage students in the active application of knowledge, principles, and values. It also provides them with feedback that allows their understanding to grow and evolve. Chickering and Ehrmann (1998) suggest that while using technology to teach, educators should avoid didactic materials and search for technology-assisted solutions that are interactive, problem-oriented, and motivate students. Students can either read or print a static Web page; with an interactive Web page, they can interact with content, other students, and instructors, as well as participate in discussion groups, quiz questions, simulation program, conferencing, live chat, or fill out a feedback form. This Web-based informal assessment represents a cognitive behavior-modification technique designed to help students develop goal-setting behavior, planning, and self-monitoring. It also allows them to master concepts (Good and Brophy 1995). For example, students can regulate and monitor their own learning in a sequential and constructive fashion as they respond to the questions and receive ongoing feedback. In traditional, as well as Web-based courses, there is a gap between what is taught and what is learned. Reid (1997) mentions that methods of assessing the teaching and learning experience in online education are in high demand but short supply. No existing measurement adequately evaluates how well a teacher performs in a virtual classroom. Angelo and Cross (1993) observed that by cooperating in assessment, students reinforce their grasp of course content and strengthen their own self-assessment skills. Furthermore, student motivation is increased when they realize that teachers are interested in their success as learners. Teachers can empower themselves by using technologies to facilitate a proven educational process of receiving and acting on feedback from learners. This will lead to pedagogical improvements in interactive Web environments for assisting teaching and promoting learning.

Top Educational Resources on the Web

Education World (www.education-world.com): A free resource for primary and secondary school educators. It includes lesson plans, articles by education experts, and information on using technology in the classroom. Developed by people with backgrounds in education, the site contains more than 8,000 pages, a weekly e-zine, and a searchable database of over 115,000 education links. Strength: a well-organized interface to the world of primary and secondary education; original material and good annotations. Weakness: needs more quality evaluation of the links so that educators are guided toward the most valuable resources. GSN (http://www.gsn.org): Global School Net Foundation is a non-profit organization dedicated to the instructional application of telecommunications at the primary and secondary school levels. It includes a registry of the best curriculum projects, tutorials, articles about Internet use in the classroom, news and discussion, and events and contests. It also includes a link to the collaborative project with Microsoft to create a comprehensive site for education resources on the Internet. Strength: appealing interface; good selections from many sources. Weakness: inconsistent design does not do justice to the depth and breadth of offerings. Blue Web’n (http: //www.kn.pacbell.com/wired/bluewebn): This is a library of Internet-based instructional information for primary and secondary school levels. You can search this database quickly by audience type, application type, content area, and other search terms. It contains activities, lessons, references, tools, and projects listed for a variety of educational audiences, and is part of the Pacific Bell initiative (Education First) and umbrella program to benefit education (Knowledge Network). Strength: quick way to search for lessons and resources; good method for reviews of resources; Weakness: a bit over-generous with the ratings stars, caveat surfer. AskERIC (Educational Resources Information Center) (http://ericir.syr.edu): ERIC is a clearinghouse on information and technology. Its collection of education-related resources is funded by the American government. AskERIC includes a question-and-answer service, a virtual library, and a research and development team. Collections are well-organized and frequently updated. Strength: broad coverage of many educational topics; extensive support for educators. Weakness: graphic slab design of Web; coverage is not deep in all areas; some resources are outdated. EDUCAUSE (http://www.educause.edu/): This association manages and uses information technology in higher education. The site includes a discussion of current issues, conference information, professional development, publications, information services, and collaborative alliances with other organizations. It focuses on the future of higher education in the information age. Strength: this site is well organized and has breadth and depth; Weakness: not all content is available online.

References

Angelo, T., and K. Cross. Classroom Assessment Techniques: A Handbook for College Teachers. 2d ed. San Francisco: Jossey-Bass Publishers, 1993. Chickering, A., and S. Ehrmann. “Implementing the Seven Principles: Technology as a Lever.” Retrieved November 3, 1998 from www.tltgroup.org/resources/darticles.html Edwards, J., M. A. Havriluk, and M. D. Roblyer, M. D. (1997). Integrating Educational Technology into Teaching. Upper Saddle River, NJ: Prentice-Hall, Inc., 1997. Erkins, G., and G. Kanselaar. “A Cooperative System for Collaborative Problem Solving.” 1995. http://www-cscl95.indiana.edu/cscl95/kanselaar.html Good, T. L. and J. Brophy. Contemporary Educational Psychology. 5th ed. New York: Longman, 1995 Knuth, R. A., and D. J. Cunningham. “Tools for Constructivism.” In T. Duffy, J. Lowych, and D. Jonassen (Eds.), Designing Environments for Constructivist Learning. Berlin: Springer-Verlag, 1993, 163-87. Reid, J., Jr. “Measurements in Online Study: Items Useful in Quantifying Pedagogical, Social and Technical Issues.” 1997. Retrieved November 3, 1998 from www.caso.com/articles/reid05.html Story, D. “World Wide Web 101.” 1996. www.thejournal.com/magazine/vault/M2311.cfm

While almost everybody who has access to a computer is somehow involved with the Internet for a variety of personal reasons, scientists and the academic community also use it for their own purposes. Examples are sharing data and information, browsing technical papers, searching for related documents, and posting their research activities to colleagues and other interested parties. Recent developments have proven to researchers and academia, both of which publish large amounts of technical literature, that the day of electronic publishing is close at hand.

The easiest way to publish electronically is to post documents on the Internet by generating Web pages. In this case, however, the user remains a passive recipient of information, for the Internet’s interactive communication ability is not being used. This particular capability of the Web allows a scientist or researcher to generate Web pages with which the user can interact. One example of such interaction is performing mathematical operations over the Internet. This is very useful and powerful, for it allows the user to become an active receiver by gathering the needed information from that particular home page.

For instance, if you visit Rice University’s home page for its Department of Mathematics, you will find several interactive math tools designed to help students taking the Ordinary Differential Equations course.3 These tools are activated by using Java or MATLAB programming language. For example, Figure 1 shows a tool called PPLANE, which draws the magnitude and direction of a differential vector in an x-y plane. PPLANE also graphs the linearization about equilibrium points, and displays eigenvalues, eigenvectors, nullclines, and stable and unstable orbits. The user can change the differential equation’s variables and then run the associated MATLAB code over the Internet. A licensed MATLAB copy in the user’s personal computer is not required, for the MATLAB routine is run on the server and displays the output on the user’s browser. This makes it easy for the student to understand how the changes made alter the equation’s features.

This technique is very efficient and powerful for a student who is still in the learning process. It also suggests that the Internet’s interactive feature will affect the education system and the way courses are taught in the future.

Another home page that contains a wide variety of interactive math tools is found at the Web site for Dartmouth College’s mathematics department.4 Professor Richard Williamson has written about 30 interactive math programs for common scientific problems. These vary from differential equations to heat equation solvers, from Newton’s method of calculating the root of an equation to simulating a swing’s motion. All of these programs are activated by the user’s input parameters, and display the answer in the same manner.

Another interesting and very useful Web site is http://www.integrals.com (see Figure 2). This interactive site allows the user to take any symbolic integral over the Internet. It is provided by Wolfram Research, which also produces the well-known and widely used Mathematics tool MATHEMATICA. After the user enters an expression, the integrator automatically runs MATHEMATICA on the server, integrates the expression, and sends the result back to the user’s browser.5 This site is already helping many calculus students with their homework, and is quite handy for researchers who deal with complex integrals in their everyday research.

Another useful interactive math Web site can be found at the Geometry Center Web page of the University of Minnesota, Science and Technology Center.6 This site offers such interactive math tools as hyperbolic triangles, Lorenz simulation, and interactive proofs of popular theorems. There is also a tool for taking numeric integrals. If you get tried of doing mathematics, you can take a break and play some Tetris games at the same site. In fact, interactive games on the Internet are also a particular type of interactive math tool. A better graphical version of Tetris can be found at http://www.geocities.com/SiliconValley/Pines/522 7/tetris.htm.

All of the above Web pages show that cybermath has found its way onto the Internet, thanks to the Web’s interactive communication capability. It is not difficult to imagine that students in other majors will apply this useful and efficient tool to their own field, thus making the Web even more interactive

FOOTNOTES

1. http://www.flifo.com/and http://www.reservations.com/, respectively.
2. http://mallblvd.net/and http://www.internet.net/index.html, respectively.
3. http://math.rice.edu/.
4. http://www.dartmouth.edu/~rewn/index.html.
5. http://www.integrals.com.
6. http://www.geom.umn.edu/.

The spider’s web is woven from a special silk. This is a fibrous protein first secreted as a fluid and then stretched into strands which, because of their strength and elasticity, are extraordinarily resistant to breakage.

Garden spiders (Arena diedemata) make their webs from two different silks. The threads of the main structure are woven from a strong silk which can be stretched further (by as much as 20%) but then loses its strength. By contrast, the other kind of silk, used between the main threads, is lighter and stickier and can be expanded three times without losing its original characteristics. Under a microscope drops containing a reserve of silk can be seen at intervals on these thinner ‘hunting silks’.

After its web is complete the spider hides out of sight, somewhere on the outer strands of the web. When an insect flies into the web and struggles, the spider is alerted by the vibrations and runs out. It rapidly contains the victim’s struggle to escape by tying it up with the silk set aside for this purpose in the drops: the elasticity of the hunting silks is vital in this task. While tying it up, the spider injects the victim with the poison from behind its jaws which both paralyses the insect and acts as a digestive juice softening up the now helpless corpse. The spider then goes on injecting and sucking back fluids until the soft parts of the corpse have been digested – any skeletal parts left over are simply discarded.

Spiders put their weaving skills to a number of different uses. As well as making the insect traps we call spider webs, they weave draglines’ that help them to locate themselves and to break their fall if they should slip. Small spiders spin a sort of ‘parachute’ thread that allows them to be carried on the wind.

Some species of spider make active traps. Menneus spins an elastic net between its legs and sweeps it through the air to catch passing insects. Cledomelea dangles from one leg a blob of sticky silk at the end of a long thread and swings it out to attach its prey. Trapdoor spiders (Ctenizidae) dig a burrow closed by a silken door; when an insect ventures near, the spider darts out to capture the imprudent victim.

Spider webs are beautiful, intricate constructions: threads which serve as scaffolding during the construction process are removed once the web, a mesh of sticky and non-sticky lines, has been completed. The skill of producing webs is clearly instinctive, but the irregularity and variety of web forms shows that the skill is adapted by individual species to serve different functions and suit different circumstances – some webs hang in the air to catch insects as they fly, others are laid across the ground, both at angles calculated (presumably by experience) to lure and intercept prey.

Recent research has shown that some A. Glomosus spiders use ultraviolet rays to attract their prey. In one experiment fruit flies (Drosophila) were set free between two webs lit up by a white beam. One web was that of a A. Glomosus spider and radiated ultraviolet rays; the other was not: the flies were attracted to the former

Another remarkable species are the Dolmedes spiders which have long legs (8-10 cm) and striped, brown bodies. They live near water ponds where they have learnt, despite having very poor sight, to catch fish. Their hunting-gathering technique is of awe-inspiring dexterity and patience, rivaling that of any human fisherman. First the spider walks around on the bank to pick a site suitable for laying a web. Once that is done, it waits patiently, standing partly on water and partly on land. A special sticky secretion helps secure its hold on the surface of the water. While waiting, it prepares its poison in its mouth. When a small fish happens by, the spider plunges forward to seize it, releasing its poison into the water as it does so. As the poison begins to work, the spider turns over making its own body a sort of float for the struggling fish, carries it to land and there consumes it.

Some species of spiders do not make webs to ensnare their prey. Instead, they actively pursue their prey or lie in ambush for it. They are endowed with specially keen sight or touch sense, used respectively for hunting in daylight or in the dark. The ambushing varieties are remarkably well camouflaged – the colour and shape of their bodies making them almost invisible against the immediate background of leaves or bark or stones and sand.

One of the night-hunting spiders of the Amazon jungle spends the day hiding in crevices or in holes in trees, emerging into the jungle at night to stalk its food. Its legs spread the width of a human hand and move with utmost stealth until, when near enough, the spider makes a sudden, final dash, seizing small mammals (humming-birds, for example), stunning them with its poison, then dragging and shaking them to death. The detestation and horror this species arouses in human beings is hardly justified – its poison is not more troubling to a human than a bee sting.

Reputation and significance

Spiders have a very negative image among human beings. Perhaps the number of legs, the grotesque facial expression, the hairiness of some species, the fact that they carry a poison, but most of all, the fact that they hide in corners and come out unexpectedly – have contributed to the spiders’ bad reputation. The poison of spiders, with just two exceptions (the ‘black widow’ and the ‘brown recluse’), is relatively harmless to humans.

Spider silk cannot economically be converted into silk cloth for human use. However, it has been used for the cross-hairs of optical instruments. More recently, the silk of the tropical species Nephila has been employed in the manufacture of bullet-proof jackets. The Nephila spin huge webs strung across trees, as long as 2 metres or more, and of a silk so strong and elastic that the local peoples make very effective fishing nets from it.

On balance, it is high time human beings overcame their irrational detestation of spiders. We should be grateful to them for all the good they do for us in preserving our persons and properties, especially our crops, against devastation by insects. One authority calculated the spider population of England and Wales as of the order of 2.5 billions at any one time. This means that if (at a most conservative estimate) each spider eats 100 insects a year, then the total number of insects consumed by spiders is 250 billions annually.

REFERENCES

‘Spiders’ Microsoft (R) Encarta. Copyright (c) 1994 Microsoft Corporation. Copyright (c) 1994 Funk & Wagnall’s Corporation.

Buton, M. & Buton, R. (1975) Enevlopedia of Insects and Arachnids, BPC Publishing Ltd, London.

Gerald, L. & Wood, F.Z.S. (1982) The Guinness Book of Animal Facts and Feats, Guinness Superlative Ltd, London.

Waterson, AR. (ed.) (t975), Collins Enevlopedia of Animals, William Collins Sons & Co Ltd, London and Glasgow.

SPIDERS IN GUINESS BOOK OF RECORDS

The largest and the heaviest spider: The Guyanan ‘bird-eating’ spider (Theraphosa

blondi) of South America has long been credited with the ‘largest spider’ title. A male specimen with a leg-span of 254mm (10 in) and a body length of 89mm (3.5 in) weighed just under 57g (2 oz).

The smallest spiders are the midget spiders (Symphytognathidae), the tiniest of which is the pale yellow Patu marplesi of Western Samoa, S.W. Pacific. A male specimen found in moss at an altitude of 610m (2000 if) measured 0.43mm (0.07 in), which means it is half the size of a full-stop on this page!

The largest spider webs are the aerial ones spun by the tropical orb weavers of the genus Nephila. Several examples found in the Karrakpur Hills near Monghyr, central Bihar, India measured 1.5m (5ft) in diameter (about 4.79m (1 5ft 9in) in circumference) and had long supporting guy-lines up to 6.1 m (2Oft) in length.

The smallest webs in the world are the aerial ones spun by midget spiders. That of the orb weaver Chasmoeephaion armaturn of New Zealand measures about 9-10mm (O.35-0.39in.) in diameter which means it is half the size of a small postage stamp.

The highest speed recorded for a spider on a level surface is 53cm/s (1 .73ft/s) (= 1.90km/h; 1.18 miles/h) for a female house spider, Tegenaria atrica. This may not seem very fast, but the spider covers a distance equivalent to 330 times its own body length in ten seconds.