spry

Boston Tea Party

             The Boston Tea Party was the key-event for the
Revolutionary War. With this act, the colonists started the
violent part of the revolution. It was the first try of the
colonists, to rebel with violence against their own government.
The following events were created by the snowball effect.
There, all the colonists realized the first time, which they
were treated wrong by the British government. It was an
important step towards the independence dream, which was resting
in the head of each colonist. They all flew from their mother
country to start a new life in a new world, but the British
government didn't gine them the possibility by controlling them.

             The events leading to the Boston Tea Party began
already ten years before (1763), when the English won the
French-and-Indian War. The king of Britain passed taxes on the
colonies to make up for the loss of money because of the war.
He did it in a line of acts, called the Sugar Act (tax to
protect and secure the colonists) and the Stamp Act ( tax on
all licences, newspapers and business papers ). The colonists
reacted with protests against those acts, what made the British
Parliament to repeal the taxes within 5 months. Then they (the
government) passed taxes on lead, paint, paper and tea. These
acts were called the Townshed Duties, but the colonists called
them the "Insidious Acts". Mass meetings were held and people
tried to influence others not to buy English imported goods
anymore. In the end the parliament removed all the taxes except
for tea. Actually the colonists easily didn't want to accept,
to pay taxes to a government, they don't really belong to
anymore. Although this tax on the tea cost a colonial family just
pennies a year. Sam Adams, a kind of leader of the colonists,
figured out, that the tax could be raised or lowered by the
parliament at will. (Sam Adams: "The power to tax is the power
to destroy!" ).He also pointed out, that the colonists had no
representation in the Parliament, and that they can't be taxed
without having a representation in there, to care for their
interests and wills. However, most people drank tea smuggled
in from the Netherlands, so they didn't care very much whether
the parliament raises or lowers the taxes. When the East India
Tea company realized, that the colonists were drinking cheap,
smuggled tea, the Parliament gave them ( the company ) the
monopoly to export tea without paying duties. That way the tea
could be much cheaper than the holland tea, even with the taxes.
This act was called the Tea Act, which was of great importance
for the following Boston Tea Party.

             The colonists reacted to this act by holding
meetings to discuss it. Supporter of the revolution (just
to name some of them: John Adams, John Hancock, Dr. Joseph
Warren) wrote letters of protest to the government's officials,
but they didn't achieve anything. The tea ships arriving in
Boston still had to pay the full British tax.

             In September, 1773, a radical group of colonists
found out, that three East India tea cargo ships, laden full
with tea, were heading for Boston under full sail. They knew,
that if the ships got unloaded and the tax would be paid, it
would be a crushing defeat.

             The same radical group wanted to make the agents
of the East India Company resign from their job in front of a
big crowd, but this part didn't work. Over the following weeks
speeches in form of propaganda were made, to get all colonists
informed about the events. People even quitted drinking tea
(what they did for their whole life ) and started drinking
coffee.

             The actual event On November 18th, 1773, the ships
arrived. Pamphlets were posted to arrange a meeting between the
citizens and the governor ( Hutchison ), called the "Committee
of Correspondence". They wanted him to call the ships back to
Britain. When he didn't agree, a bunch of men, disguised as
Indians, went and stormed towards the harbor, planning to throw
the tea into the bay. They divided in three groups, each of them
with one leader. After they made the captain and his crew getting
down below, they grabbed all the boxes of tea, opened them and
threw them overboard. Even some members of the crew helped them
to destroy the tea. A big crowed was created in the harbor, some
of them even tried to steal some tea. Altogether they destroyed
340 chests. At 10:00 pm the event was over, and the streets of
Boston were empty again. The next day everybody was happy, and
plans were made, to public the important event in all colonies
of America.

                 The reactions of the British Government were
called the "Intolerable Acts". The Boston Harbor was closed by
4000 British soldiers, so that Boston couldn't get any food or
other important goods. But this act failed it's mission, because
the other colonists sent the Boston citizens food and other
life important goods. They also created a militia to protct
themselves of the British army. They also weren't allowed to
held any meetings in Boston anymore. These tries to get the
colonies under their control again were the last ones with a
view of success.

spry

Many shows include violence as a key factor to interest public
viewers. However, people may think television violence is one
of the many causes for everyday violence. Dr. Littner has
slightly disagreed with this theory and explained his reasoning.
Dr. Littner believes that television does not create the desire
for violence but supports the existing desire that cannot be
taken away. Personally, I agree with Dr. Littner’s opinion
because his reasoning is rational and logical. If a mature
teen were following a television program that included rape,
it would be very unlikely for him/her to go out and rape a
person. On the contrary, if an emotionally disturbed teenager
were following the same program, the chances would be more
likely for him/her to rape a person. The maturity of the
viewer, the way in which the violence is shown, and the age
of the viewer are all factors that affect violence caused by
television. If the viewer is very emotionally disturbed then
the more likely for the viewer to have difficulty controlling
his/her disturbed emotions. It may also be unsafe if the
violence is presented unrealistically and is purposely shown
to attract an audience. A mature adult may be angered and
insulted by inappropriate displays of violence. A normal
adolescent may not know how to handle violence and as a result
may be attracted to the violence. The television show, “Beavis
and Butthead”, which is an animated show with two boys playing
practical jokes for fun, shows the significance of the age of
the viewer. The jokes consist of dangerous results if taken
literally. For example, a few years ago, the show had the two
animated characters light a curtain on fire. About two weeks
later, the news announced that a young boy had lit his curtains
on fire, which led to an explosion. It was said by the news that
the show “Beavis and Butthead” had caused the young boy to do
so. This example explains exactly how the swayed audience of
violence can lead to destruction, being that the young boy was
too young to understand the consequences.

[此贴子已经被spry于2002-11-5 22:28:57编辑过]

spry

IT Technology

             The successful company will be driven to increase
stakeholder value and profitability while creating a working
environment that encourages and nurtures the growth of personal
creativity and development as well as nurturing a sense of well-
being for all members of the organization. When dealing with the
forces that drive industry competition, a company can devise a
strategy that takes the offensive. This posture is designed to
do more than merely cope with the forces themselves; it is meant
to alter their causes. The IT professional's role in competitive
market intelligence The IT professional is increasingly being
called upon to be a sleuth in the quest for the competitive
market intelligence that is so necessary to support the
enterprise's overall business strategy. In today's fast-changing
marketplace, it is essential to monitor the techniques of similar
businesses, and IT is being called upon to fulfill that
functional need. IT must provide marketing with answers to vital
questions such as: 1. How are competitors getting business?
2. Where does the enterprise look for new customers? 3. How are
prospects targeted? 4. What services, products, and prices do
competitors offer? 5. What images do our competitors project,
and how does that compare to our image? The combined strength
of marketing and IT Enterprises have depended on marketing for
too long to provide competitive intelligence. It is crucial for
IT professionals to contribute their specialized expertise to
successfully adapt to the changing dynamics of the market arena.
Marketing cannot do the job without the cooperation, tools, and
willing support of the IT department. With the combined strength
of the two complementary functions, a winning competitive market
intelligence program is within the enterprise's reach. Useful
and sometimes surprising insights can be gained from exploring
the terrain of actual and potential competitors. Hardly an
academic exercise, sizing up the competition should become an
ongoing, regular, and systematic process of gathering, analyzing,
and acting upon relevant data, which will provide businesses with
two tangible benefits:  It will reveal the steps that
management must take to preempt competitive strikes. 

It will signal new market opportunities. Competitive monitoring
enables management to develop practical strategies and measure
the success of their actions. What you should know Simply
knowing who your competitors are is not enough; you should also
ferret out what their strategies and objectives are. You can
gauge their strengths and weaknesses by learning about their
products and services (current and new), pricing, features, and
the level of customer satisfaction. How are your products or
services positioned relative to the competition? Do your
customers and prospects see your service as having the highest
quality and still selling at the lower price? Is your product
viewed as the low-cost brand, the premium-priced brand, the old
standby, or the leader? After getting some comments, it may
still be neither possible nor desirable to change your service's
features. Instead, research could point out what to communicate
and how to communicate to your market. For example, you could
tell your marketing department what potential customers are
looking for and highlight the features that are valued by your
customers. Your information will enable the marketing people
to create materials that tell customers what they want to hear
and sell them what they want to buy. Differences can be subtle
but they really do matter. Are yesterday's customers and clients
being lured away by today's competition? Are they being tempted
by the competition's siren song? Are they saying yes to your
rival's lower fees or discounts? Are they buying new products or
services that your company has not even thought of offering? Who
will provide the answers? IT can, at the very least, provide
meaningful data to formulate the correct solutions. Potential
market threats While management understands the importance of
keeping an eye on the competition, some members of management
mistakenly believe that the marketing department alone has the
resources to do a proper job. This is simply not true. Much
valuable information exists in the database mines of the IT
function. The IT professional must do some of the digging in
those mines to find it. Most IT professionals are already in an
excellent position to obtain and use primary competitive
information and need only the encouragement or permission of
management. Frequently, IT has become the central repository for
this kind of competitive analysis information. However, using the
information can be a challenge when different departments within
the company engage in territorial squabbles, and the company is
forced to dilute valuable resources through unnecessary
duplications of effort. In such situations, management must educate
all departments to funnel customer and prospect data back to a
central IT point. Emphasize your strengths The benefits of a
competitive intelligence effort coordinated by the IT department
are: 1. Learning the enterprise's strengths and weaknesses.
2. Learning whom is and who is not buying.
3. Determining customers' and prospects' buying plans.
4. Anticipating rather than reacting to the market.
5. Taking the competition seriously.
They are not going to vanish. Equally important, but
occasionally overlooked, is that competitive research, if done
well, can give your company a refreshing appreciation of the
role of the IT function and a better understanding of your
company's own competitive strengths. You may discover, for
instance, that your firm's style or delivery is more appreciated
or valued by customers than management may have realized.
Knowing this facilitates your exploitation of those strengths.
Conclusion In conclusion, the awareness of these forces can help
a company stake out a position in its industry that is less
vulnerable to attack. Many factors determine the nature of
competition, including not only rivals, but also the economics
of particular industries, new entrants, the bargaining power of
customers and suppliers, and the threat of substitute services or
products. A strategic plan of action based on this might include:
positioning the company so that its capabilities provide the best
defense against the competitive forces; influencing the balance
of forces through strategic moves; and anticipating shifts in the
factors underlying competitive forces. Increasingly, corporations
are recognizing the strategic role of the operations function.
These organizations are discovering that a focus on customer needs
is effective only if the operations function is designed and
managed to meet those needs. From acquiring raw materials to
fabricating parts, to assembling products, to customer delivery,
a total systems perspective can enable them, in the ideal, to
fashion an operations function like the inner workings of a finely
tuned machine. Today that operation can be fine-tuned by using
modern information systems.

spry

Gun Control

             Gun control is an action of the government that is supposed to reduce crime. Congress has passed many laws on this subject and there really has not been an effect. Gun control has been a controversial issue for years, but the citizens of the United States have a right to own guns and the Constitution states that. On the government's path to control guns they created the Brady Act. Handgun Control Incorporated is the major organization for lobbying, and introducing legislation on gun control. It is headed by Sarah Brady, wife of former White House Press Secretary James Brady. James Brady was shot during an attempt on President Reagan's life in 1981. Sarah is the one responsible for introducing this bill. This bill was supposed to stop criminals from obtaining guns. If an individual wants a firearm bad enough, chances are they will get one (Brennen and Polsby). All it does Is prevent honest people from being able to purchase guns. The person purchasing the gun has to wait for two week while the government performs a background check. The problem with this is it stops the average citizen from purchasing a gun on the whim, while it protects the common criminal. What if a burglar enters a house with full intention to maim or kill? The innocent victim can not get a gun to protect his family because he was arrested seven years ago for drunk driving (Larson). According to the General Accounting Office, in the first seventeen months of the law's existence only seven criminals were convicted for attempting to buy a handgun. Banning more and more guns may reduce gun violence, but it will not eliminate guns from society and will only lead to more and bigger problems. While continuing to take more freedom away from the American people. Gun control laws do not prevent little kids from using guns and harming people. Violent video games help children with their marksmanship and to get over their fear of shooting someone. Parents of three slain girls in the Heath School shootings are going after the manufacturers. They feel that violent video games are partially responsible for their children's death. They claim that the video game taught the shooter how to be an excellent marksman. The boy had never used a gun, but was skilled enough to hit eight moving targets in only eight shots (Prichard). Another fact that backs up the parent's belief is that of military training. Each year billions of dollars are spent to train police and the military how to shoot. Video simulation is the best way to help overcome the natural resistance that most people have about shooting someone. Studies show that people are extraordinary susceptible to programming. One main difference between military training and video games is that military instructions are constantly pausing the action and where the video game is in constant action (Blakemore). There is no direct relationship between the number of guns and the amount of crime in the United States. Between 1973 and 1992, the rate of gun ownership increased by forty-five percent while the homicide rate during that period fell by nearly ten percent. Even with the increasing number of guns in society the homicide rate decreased, highlighting that guns are not the root of the problem, people are. Guns do not kill people, people kill people. Guns do not work as self-protection against criminals. Guns are just as valuable to civilians as they are to police officers. As many as sixty-five lives are protected by guns for every life lost to a gun. Every year potential victims kill between two thousand and three thousand criminals, and wound an additional nine thousand to seventeen thousand. Private citizens mistakenly kill innocent people only thirty times a year, compared to about three hundred and ten mistaken killings by police. Criminals succeed in taking a gun away from an armed victim less than one percent of the time. Gun control laws are needed to prevent the purchase of saturday night specials and assault weapons. Criminals generally prefer larger caliber and more expensive handguns (Brennen and Polsby). President Clinton proposed a restriction on armor piercing ammo. However, the FBI reported that sixty-eight percent of officers killed were not wearing a vest. Of those killed wearing a vest ninety-five percent were shot in unprotected areas. Many people like to use guns for recreation use. The NRA, National Rifle Association, even has its own hunting magazines. These magazines are the American Hunter and American Rifleman. Hunting is a great sport and with these new gun control laws it is harder and harder for good citizens to buy guns for recreation. Hunting is not only a sport but also a hobby. Target shooting is even part of the Olympics. Another thing people use guns for is target practice. This is mostly for personal safety. The better marksman you are the easier it is to protect yourself. Some people even like to shoot targets for fun. The government has no right to take away hobbies from the American people, especially if its not hurting anyone. The government keeps chipping away at our right as American citizens by imposing gun control legislation. There are several major anti-gun control groups. These groups include the National Rifle Association (NRA) and the Gun Owners of America (GOA). The National Rifle Association is a national group dedicated to the upholding of the Second Amendment of the Constitution. In their magazines, American Hunter and American Rifleman, they say, "The National Rifleman Association believes that every law-abiding citizen is entitled to the ownership and legal use of firearms." The National Rifleman Association does many things to help display their beliefs and persuades others to their beliefs. This association also has a strong influence on legislation, because it has many lobbyists and supporters in government. This group has many members in Congress, and former presidents George Bush and Ronald Reagan are NRA members. The Gun Owners of America is another group that is against gun control. The Gun Owners of America preserves and defends the rights of gun owners through legislation. They publish books, articles, and videos on gun issues and how those issues affect people. They also conduct seminars for the press and Congress about issues on the Second Amendment, and gun issues. The GOA opposes bans on semiautomatic weapons, armor piercing ammunition, and handguns. The Second Amendment states that, "A well-regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed." The functions of the militia as stated in Article 1, Section 8, clause 15 of the Constitution are to execute the Laws of the Union, suppress insurrections, and repel invasions. If we allow the government to regulate and ban the only effective method of defense the people have, then on that day this country will no longer be one ruled by the people and for the people, but instead one that has surrendered all its power to the government. With the apparent failure of gun laws one could agree that more is not the answer. Banning guns will not solve the crime problem it will only change the method. If guns are not available then another weapon will be used or an older gun. Simple laws will not stop a person who is determined to cause someone harm. This is why people should be allowed to own and carry guns. This allows them to protect themselves from those kinds of people. Proper education in school and other places to teach how to use a gun and to respect guns as a dangerous weapon is what is needed to reduce gun violence in the future. If we allow the government to ban guns the American people will be defenseless and powerless to stop the government from taking over or to stop an outside invasion if either were to occur. This country was born because the citizens were armed and could fight for themselves. How can we remove the very object that helped give our country its freedom?

spry

ADAM SMITH AND JEAN JACQUES ROUSSEAU.

Adam Smith(1723-1790) and Jean Jacques Rousseau(1712-1770) each provide their own distinctive social thought. Smith, political economist and moral philosopher, is regarded as the father of modern economics. Rousseau, a Franco-Swiss social and political philosopher, combines enlightenment and semi-romantic themes in his work. Thus Smith’s work places emphasis on the relationship between economics and society, whereas, Rousseau focuses his attention on the social inequalities within society. Therefore, Smith and Rousseau, of the Scottish and Continental Enlightenment respectively, provide unique insights on their existing society. Adam Smith is one of the main figures in the Scottish Enlightenment. Smith’s main concern was the establishment of the free market, as laid out in his work “The Wealth of Nations”(1776). In the “Wealth of Nations”, Smith is very critical of the division of labour. The emphasis falls equally on the economic and social consequences of the division of labour(Smith, 1998:26). Moreover, “What is significant about the contribution of the Scottish Enlightenment to Sociology is the clear awareness that society constituted a process, the product of specific economic, social, and historical forces that could be identified and analyzed through methods of empirical science. Society was a category of historical investigation, the result of objective, material causes”(Smith, 1998:26). Smith believed that society would benefit from individuals who were self-interested in their own personal economic gains. Furthermore, Smith believed that the division of labour had a negative impact on society. He thus was very critical of the divison of labour. For Smith, “the man whose life is spent in performing a few simple operations, of which the effects too are, perhaps, always the same, has no occasion to exert his understanding…He naturally loses, therefore, the habit of such exertion and becomes as stupid as it is possible for a human creature to become”(Lecture Notes, 2001:5). Smith clearly argues that the division of labour halted the growth and development of the people. If the people are unable to progress, Smith believes that society suffers as well. In essence, for the society to progress and development, the people must do so first. Therefore, the division of labour, in Smith’s perspective, conflicts with the ideals of the Scottish Enlightenment thinking of individual progress and development. “For Adam Smith, the development of a commercial society produced a social structure divided into three classes, landowners, capitalists, and labourers, ‘the three great constituent orders of every civilized society’”(Smith, 1998:27). Thus, Smith’s ideal society would be of people would work for themselves. He was a strong advocate for free market and posed strong opposition to the feudal system. He, along with other Enilghtenment thinkers, believed that the State had no legitmate role in the free market. Smith’s defence of the free market was tied to the belief that state interference with the market benefits the rich and hurts the poor(Lecture Notes, 2001:5). Therefore, Adam Smith’s vision of an ideal society was one in which most people are involved in independent commodity production(Lecture Notes, 2001:5). Thus for society to develop and prosper as a whole, its individual members must serve their self-interests. Jean Jacques Rousseau’s work, in contrast to Smith’s, gives attention to the social inequalities within society created by social development. Rousseau believes the social development that the Scottish Enlightenment thinkers advocate, actually create a web of problems that previously did not exist. More specifically, his work concentrates on the articificial social inequalities. “The artifical refers to the specifically socially or conventional aspects of reality – the conditions of human life that are contrived or invented by human beings themselves”(Smith, 1998:10). This means that people themselves are responsible for creating the social inequalities that exist within society. “Rousseau’s contrast of the ‘noble savage’ with ‘civilized man’ illustrates this conception; the former exists in a state of nature that provides everything necessary to a free and happy existence, while the latter is enslaved by all sorts of artificial wants and desires”(Smith, 1998:10). Thus, this comparison that Rousseau uses illustrates clearly that social inequalities is a result of social development. The ‘noble savage’ as Rousseau refers to, is not bounded by the artificial social inequalities that contrain the ‘civilized man’. Rousseau’s critical view of society is based upon his theory that the social inequalities existing in society conflict with the laws of nature. “Rousseau declared that it is plainly contrary to the law of nature…that the priviledged few should gorge themselves with superfluities, while the starving multitude are in want of the bare necessities of life”(Smith, 1998:10). These problems did not exist for the ‘noble savage’, however, the ‘civilized man’ lives in a society that creates and perpetuates social inequalities amongst its members. Rousseau states that, “society creates more compex needs and therefore a more complex humanity than that found in the state of nature”(Smith, 1998:16). Thus people are responsible for creating artificial differences among themselves. Adam Smith and Jean Jacques Rousseau view society from different perspectives. Smith concentrates his attention on economics and individual development, whereas, Rousseau discusses the consequences of social inequalities that have arisen from social development. Smith advocates self-interest as a means for the society to develop and prosper, and in contrast, Rousseau sees this self-interest and development as the cause for social inequalities. Inequalities, that Rousseau believes, naturally do not exist.

iamf

Bad News for Warts and Sores


New vaccines against two common sexually transmitted viruses may reduce their transmission rates significantly. Although larger trials have yet to be completed, the initial results--published 21 November in The New England Journal of Medicine--have thrilled infectious disease experts and doctors.

Human papilloma virus (HPV) causes genital warts and cervical cancer and infects about 20% of adult U.S. women. The new vaccine targets a version of the virus called HPV-16, which has been linked to 50% of cervical cancer cases and suspicious pap smears. Epidemiologist Laura Koutsky of the University of Washington, Seattle, and colleagues injected a synthetic version of the virus's protein shell--which normally houses the virus's DNA--into 768 women. Another 765 women received a placebo injection. After 7 months, none of the vaccinated women had persistent infections of HPV, whereas 3.8% of the women in the placebo group did, indicating a remarkable 100% efficacy.

The second vaccine is for herpes simplex virus-2 (HSV-2). The sexually transmitted virus sometimes creates painful genital blisters, but 80% to 90% of the people who have it have no symptoms. The virus can be transmitted to babies if the mother is shedding virus during labor; left untreated, HSV kills about half of its newborn victims. Researchers have been attempting to make an HSV vaccine for more than 50 years, with no luck.

To create the new vaccine, researchers combined one of the proteins that make up the herpes virus shell with a compound that helps the immune system cells fight infections. About 73% of the women injected with this vaccine were protected from HSV-2. But to the researchers' surprise, the vaccine did not work in men. It also did not protect women who were already infected with HSV-1--the herpes virus that causes cold sores in up to 90% of adults. Even so, says lead author Lawrence Stanberry of the University of Texas Medical Branch in Galveston, over time the vaccine could stem the current rise in new infections, even in men, as the number of infected women decreased.

Larger studies are currently under way with both vaccines. Pathologist Christopher Crum of Brigham and Women's Hospital in Boston likens the HPV vaccine result to the discovery of the poliovirus vaccine. Likewise, infectious disease researcher Thomas Heineman at St. Louis University, Missouri, says the herpes vaccine "is exciting news. I had to read [the paper] twice to convince myself that this was as good as they say."

--MARY BECKMAN

tongxun

iamf ：thanks！

iamf

Fewer Fires From the Sky


Asteroids don't have to strike Earth to wreak havoc. Building-size rocks can blow up overhead, unleashing shock waves that pummel the ground. However, don't lose sleep over this threat: A new study based on satellite images of small asteroid bursts in the atmosphere suggests that the most harmful explosions happen only about once a millennium--about four times less often than previously thought.

Bright burst. Small asteroids often explode overhead, such as this 1999 bolide over the Czech Republic in 1999, but damaging blasts are less common than expected.
CREDIT: P. SPURNY/ASTRONOMICAL INSTITUTE, ONDREJOV OBSERVATORY  

The most recent violent airburst struck in 1908 near the Tunguska River in Siberia. It was a weak asteroid, perhaps 50 meters wide, that never hit the ground. But the shock from its detonation flattened trees over hundreds of square kilometers. The blast's energy packed as much punch as 10 megatons of TNT; a similar event over an urban area today could kill millions of people. Earlier estimates from counts of asteroids and craters imply that a Tunguska-size airburst should happen somewhere on Earth every 200 to 300 years--a rare but not vanishingly small risk.

Images from government satellites have helped researchers refine that calculation. Meteor scientist Peter Brown of the University of Western Ontario in London, Ontario, and his colleagues analyzed previously classified data from U.S. Department of Defense and Department of Energy satellites. These sentinels watch for nuclear tests, but they also catch hundreds of bolides--small asteroids that explode into fireballs.

Brown's team studied the light from 300 such airbursts in the last 8.5 years. The scientists converted the optical signals into an energy for each blast, calibrated by other data on sound waves and speeds for a dozen of the events. In the 21 November Nature, they report that a bolide equal to 5 kilotons of TNT blows up in the atmosphere about once per year. That's a spectacular show, but it's not big enough for a shock wave to hit the ground. As for the bigger, badder bolides, the team extrapolated between the energy ranges of the 300 airbursts and those of the far rarer impacts. Damaging 10-megaton explosions strike Earth's atmosphere just once per 1000 years, on average, they deduced.

That extrapolation is a convincing use of the best existing data, says planetary astronomer Robert Jedicke of the Spacewatch program at the University of Arizona, Tucson. "But variations in the impact rates are inevitable," he adds, because disrupted comets or collisions among asteroids can create more intense streams of objects. Brown agrees, noting that 8.5 years of data isn't nearly long enough to account for such episodes.

--ROBERT IRION

iamf

First Dogs an Asian Export


An analysis of genetic material from fossil dogs shows that canines in the Western Hemisphere have Asian ancestries. The new evidence suggests that when the first humans walked across the Bering Straits to North America 10,000 to 15,000 years ago, dogs were by their sides. In addition, other genetic comparisons between modern dogs point to East Asia as the initial site of domestication of man's best friend.

Evolutionary biologists have long debated where the first wolf-to-dogs transition occurred and whether a second such transition occurred in the New World. They are hampered by a sparse and confusing fossil record. So Jennifer Leonard, now an evolutionary biologist at the Smithsonian National Museum of Natural History in Washington, D.C., and her colleagues turned to DNA preserved in fossil bones.

Working with Robert Wayne of the University of California, Los Angeles, Leonard studied DNA from 37 dog bones found at pre-Columbian archaeological sites in Mexico, Peru, and Bolivia, as well as 11 DNA samples from dog remains deposited in Alaska before the arrival of the first European settlers. The ancient DNA was just like modern Eurasian dog DNA, the team reports in the 22 November issue of Science, indicating that these ancient dogs were close kin to their Old World counterparts. The American gray wolf proved to be just a distant cousin. It appears that dogs accompanied humans into the New World?and sired New World canines, says David Hillis, an evolutionary biologist at the University of Texas, Austin.

These Old World dogs first appeared in East Asia, most likely China, according to work by Peter Savolainen of the Royal Institute of Technology in Sweden and his colleagues. Savolainen's DNA studies involved some 500 samples from modern dogs and about 40 from wolves. As they report in the same issue of Science, the DNA sequences were similar enough to suggest that the ancestors of all these animals came from the same place. He and his colleagues determined that dogs from East Asia had the most ancient pedigrees and were likely the source of the rest of the world's canines.

I was very excited to read these articles,says John Olsen, an archaeologist at the University of Arizona, Tucson. The evidence is bringing us closer to a resolution [of these questions].?

iamf

Sensing Love in the Air

  

Pheromones are nature's messengers of love: chemicals that help animals identify mates and get them in the mood for romance, even over long distances. But how pheromones act on the brain remains vague. Now, neuroscientists have directly spotted the first receptor to bind a known pheromone. This major step will help scientists dissect the molecular machinery involved in complex behaviors like courtship and aggression.


The mouse vomeronasal organ--a cavity tucked inside the nostrils--features a dense network of neurons that sense pheromones. These neurons are directly wired to brain areas driving sexual appetite, aggression, and stress, but they bypass those involved in voluntary actions. Earlier this year, researchers analyzing the sequenced mouse genome brought to light a family of 150 genes that might code for pheromone receptors. All the genes are expressed only in vomeronasal sensory neurons. Consistent with a role as pheromone sensor, each neuron expresses only one of these genes. But subsequent studies pointed to other functions for these genes, and their role as receptors remained unclear.

Now, neuroscientist Ivan Rodriguez and colleagues at the Universities of Geneva and Lausanne in Switzerland have examined neurons that express a gene called V1rb2, one member of the putative pheromone receptor family. The team first engineered mice in which neurons with V1rb2 also gave off a green glow when exposed to certain wavelengths of light. Rodriguez and his team then used electrodes to measure the activity of the glowing neurons in response to about 20 known pheromones. The green cells revved up their activity when exposed to a particular pheromone found in mice urine. In contrast, neurons lacking V1rb2 didn't respond to this pheromone at all, the team reports online 18 November in Nature Neuroscience.

The findings fill an important gap, says neuroscientist Catherine Dulac of Harvard University: "It's an experiment that somebody had to do." But the really important question now, she says, is how pheromone signals go from the receptor into the neuron and affect processes in the brain that mediate behavior.

--CHRISTIAN HEUSS