[分享]阅读机经相关英文背景材料---持续更新（至机经39飞蛾拟声）

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buda

Cast-iron way to save the planet

Humans may one day adjust the carbon dioxide levels in the atmosphere by fertilising the ocean with iron, according to evidence from ocean-going robots.

Researchers tracked a patch of iron-fertilised plankton for many weeks in the Southern Ocean, according to the journal Science today. They used floats which sank up to a kilometre several times a day, measuring concentrations of organic carbon within and beyond the fertilised area. The researchers showed that for every atom of iron added to the water, the plankton carried between 10,000 and 100,000 atoms of fixed carbon below 100 metres.

Oceans are blue because they are relatively barren. Coastal waters are green because they are rich in nutrients such as nitrates which run off from the land to stimulate plant growth, which in turn feeds a variety of marine life.

For more than a decade, atmospheric scientists have debated the role of the oceans in getting rid of carbon dioxide. But life in the oceans depends on more than just nitrogen and carbon dioxide to nourish growth. Several experiments have tried to measure what would happen if an essential micronutrient such as iron was added to ocean waters.

Climate scientists suspect iron-rich dust blown out to sea during the ice ages would have stimulated plankton growth and lowered atmospheric carbon dioxide. So if iron served in the past as part of the climate machine, some scientists have argued, it might one day be pressed into service again.

The iron released by experimenters certainly made the plankton bloom, but the experiment has yet to prove that, overall, this would remove enough carbon dioxide from the atmosphere to make a difference.

"If the phytoplankton are just eaten at the surface, or don't sink to any great depth, then the carbon is eventually released back into the atmosphere," said Burke Hales of Oregon State University, one of the experimenters. "We weren't out there long enough to observe the season to season changes, so we don't know if the carbon was really being exported to the deep oceans."

buda

The economic value of housework
New survey to track women-dominated labor
By Kristen Gerencher,
            CBS.MarketWatch.com
Last Update: 7:00 AM ET Jan 17, 2001
 

SAN FRANCISCO (CBS.MW) -- The nation's Gross Domestic Product is the 500-pound gorilla of economic measures, yet it excludes millions of women's contributions. That may soon change.

The almighty GDP doesn't account for unpaid cleaning, cooking, child or elder care, the frequently female tasks comedienne Roseanne Arnold first mock-glorified with the job title "domestic goddess."

But that work could be added in a GDP "satellite account" after the launch in 2003 of a new survey on how Americans spend time, according to the U.S. Commerce Department.

The Labor Department is now designing questionnaires, survey samples and software for the first government-funded research that will track 2,000 respondents as part of a monthly population survey.

Even if the data doesn't accompany the GDP, collecting and making it available allows the U.S. to join a growing club of nations that recognize the value of so-called non-market activity, Labor Department economist Diane Herz said. "A lot of people have been clamoring for it for some time."

Among those were former Congresswoman Barbara Rose Collins, whose "Unremunerated Work Act of 1991" first brought the issue to the Feds' attention, Herz said.

Evaluating unpaid work was also on the agenda at the Beijing United Nations' World Conference on Women in 1995. Twenty-two countries including India, South Africa, and Sweden have done time use surveys, and 25 more plan to start them.

Growing awareness

The price of domestic chores has moved to the forefront as more working women have less time and have to hire help, said Heather Boushey, an economist at the Economic Policy Institute.

"We're increasingly placing a value on household services, so it becomes easier to make the case that paid or unpaid, these services have value."

Traditional women's work has been excluded from the GDP because tax-collectors and businesses don't have an interest, Boushey said. On top of that, economists didn't know how to
count it when they created the GDP in the 1940s, said David Levine, an economics professor at the University of California at Berkeley.

"The reason they defined GDP as goods and services is because it's easy to measure, and it also was almost exclusively men who work for pay making the decisions."

The same complexity in assigning value where no money changes hands holds true today, said Marvin Kosters, economist at the American Enterprise Institute. GDP valuations are "crude because they only include things that involve market transactions."

Many people participate in activities like volunteering that aren't included, and some things like washing a car are subjective -- it could be one man's unpaid work and another's leisure activity, he said.

"Most people recognize that things like child care, for example, in the home by mothers, is worth a great deal. I don't think it gets denigrated just because it's not in the GDP."

Politics of housework
        

But the stigma of unpaid labor is unabated, said Riane Eisler, author of "The Chalice and The Blade." Talk about family values falls short when the work supporting it isn't assigned a standard currency.

"There is a growing consciousness that we have to change what we call productive work, and that we would have no economy at all if we didn't have this work," she said.

"There's a huge economy that's invisible and we have to make it visible. One of the most practical first steps is to include actual caretaking -- maintaining a safe, healthy environment -- in the calculation of the GDP."

While men also do housework that doesn't show up on official fiscal tallies, typically their chosen tasks such as mowing the lawn and tending the yard are less routine and time-consuming, University of Pennsylvania sociologist Constance Gager said.

Even men who have done a lot of drudgery as bachelors decrease their participation substantially when they marry. "Women are slaving away working 40 hours a week plus doing two thirds of the housework, and I think not getting enough attention for that."

Investing in human capital

Unpaid child care is one of the largest oversights of economic record-keeping, Gager said. "Even when it does get counted in the GDP, it's one of the lowest paying jobs."

Fulltime child care providers earn an estimated $222 a week, according to the Labor Department.

"We pay more in the monetized economy to people who park your car than to people with whom we entrust our children," Eisler said. "It's all part of the so-called devaluation of women's work of
caregiving."

Boushey said she doubts unpaid housework will be included in the GDP, but may show up in alternative or corollary measures. "If a woman hires a nanny to keep working, that's in the GDP. If she stays at home and takes care of her own child, that would be a net loss for the GDP. That makes no logical sense whatsoever."

Tracking unpaid work would lend it prominence, she said. "It gives it some credibility, that it's crucial to the functioning of the society."

Time-use data also could provide insight into the social costs of women who stay home with their kids, a decision many make because they feel it's more socially acceptable for them or because their husbands make more money than they do, Gager said.

"What you end up with is women making these constrained choices. Society is losing out by those lost wages, and if we always have women staying home, do we really have the best minds and best people out in the work world?"

What it means

Tracking unpaid work will give economists a better measure of all goods and services in the economy, Levine said. "We'll be able to distinguish an increase in goods and services from a shift in goods and services done outside the market and non-market pay."

The new data also will allow lawyers to make future earnings projections for unpaid workers collecting damages in wrongful injury and death cases, said Herz of the Labor Department.

Perhaps the biggest benefit is having the information required to make policy decisions. Measuring unpaid work poses the question: Should it be compensated, and if so, who should pay for it?

Individual couples are natural candidates for wealth redistribution, Gager said. "We might make a start by asking husbands to pay their wives who stay home an actual salary that's taxable. Those taxes on that amount could help pay for other women whose husbands are not so wealthy."

But husbands aren't their wives' employers, and it's up to a combination of government and private sector initiatives to propose payment and pension plans for unpaid laborers, Eisler said.

Boushey agreed, adding that the data could be used to expand child care credits to allow parents to stay home if needed, foster a paid maternity leave program, or reinforce corporate policies.

"We should be offering employees flex time and the ability to balance work and life."

Yet for all the prospects measuring unpaid work has in the U.S., it's countries that don't have large market economies that would gain most from collecting time-use statistics, Levine said. Village markets run by women who barter and operate small farms often fall under the economic radar, choking the flow of capital.

"Unpaid or non-market work is a tremendous amount of what leads to higher and lower standards of living," he said. "It's important that people allocating credit and agricultural agencies recognize the important economic role women have in every country in the world."

buda

Divestiture and its implications for innovation and productivity growth in U.S. telecommunications

Article Excerpt
1. Introduction

The Schumpeterian Hypothesis (1) suggests the social cost of monopoly may be a price that must be paid for rapid technological advancement. Thus, there is a tradeoff between "static" efficiency losses, reflected in higher prices and lower output due to monopoly, and "dynamic" progressiveness (Nelson and Winter 1982). Over the long run, however, the gains to society from continuing innovation may vastly outweigh those achieved through competitive pricing. This purported tradeoff has been central to the controversy surrounding antitrust policy in the United States, including the recent antitrust case against Microsoft, which had raised serious possibilities of a breakup of the company. Even though the Microsoft case seems headed for a settlement, (2) it has brought to the fore important questions about the antitrust policy and its effects.

In that context, the landmark breakup of American Telephone & Telegraph Company (AT&T), less than two decades ago, represents a classic example. It was an experiment aimed at increasing competition and productive efficiency in the U.S. telecommunications industry. Divestiture of AT&T in 1984 split the industry vertically between local and long-distance operations. While AT&T's local operations were divided among seven regional holding companies, AT&T itself was left with a competitive long-distance service. Divestiture also resulted in the breakup of Bell Labs, the centralized research division of the Bell System into two parts--AT&T Bell Labs, which was a part of AT&T, and Bellcore, jointly owned by the seven regional holding companies. Dismantling the monopoly structure of the U.S. telecom industry provides a unique opportunity to examine the effects of antitrust policy on competition, innovation, and productivity.

Kwoka (1993) and Crandall and Galst (1995) provide preliminary assessments of the impact of deregulation on productivity. These studies use a total factor productivity decomposition approach to study the effects of competition and scale economies on productivity growth. Other productivity studies include Staranczak et al. (1994), a cross-country study including the U.S. telecommunications industry, and Resende (1999), which looks at productivity growth and regulation in local telephones. Almost all these studies show that competition had a positive effect on productivity growth, although divestiture itself seems to have affected productivity negatively.

There are few known studies that statistically test the effects of divestiture on innovation in the telecom industry. Noll (1987) provides a nontechnical examination of the impact of divestiture on AT&T's research and development (R&D) activities, while Noam (1993) gives a broad overview of the impact of divestiture on prices, service, productivity, and research. These studies indicate that AT&T's R&D outlay, in terms of the number of people employed and the volume of investment, has done well from divestiture. Despite a large body of empirical literature on productivity in U.S. telecommunications, studies have generally ignored the potential link between R&D and productivity growth.

The present study uses a simultaneous-equations framework to examine the interrelationship between market structure, R&D, firm size, and productivity before and after the breakup of AT&T. This allows us to capture the possible simultaneity that may exist between R&D and productivity and also to statistically test the effects of divestiture on productivity and R&D activities of AT&T.

Prior to divestiture, AT&T was involved in providing both interexchange toll services and local services. However, since divestiture, AT&T no longer provides local access. This raises the question, is it still meaningful to compare pre- and postdivestiture AT&T? (3) The objective of this article is to analyze the impact of government policy, namely divestiture, on the behavior and performance of AT&T. Government policy action brought about sweeping changes in the telecommunications industry, reducing AT&T from a protected monopoly providing every possible telecom service to one providing only long-distance services. In addition, the market for long-distance services was opened to competition even as local services remained protected. A major argument in favor of deregulation of AT&T was that market forces and competition would improve AT&T's productive efficiency (Noam 1993). At the same time, however, some argued that breaking up AT&T would have dire consequences on research (Noll 1987) as the company was re duced to a fraction of its former self. However, the results from this study show evidence to the contrary. Average productivity for the period 1985-1994 remained below the averages for the previous two decades. On the other hand, despite its smaller size, AT&T's spending on R&D was appreciably higher than before the breakup, which is significant!

The structure of the article is as follows. Section 2 provides a brief background of the deregulation of U.S. telecommunications and reviews the evidence. Section 3 discusses the analytical framework and the measurement of total factor productivity for AT&T. Section 4 presents the regression model. Section 5 provides estimation and results, and section 6 concludes.

2. Deregulation of U.S. Telecommunications

The telephone industry in the United States was changed radically on January 1, 1984, when AT&T was divested of its local operations and left only with competitive long-distance services. This marked the end of a century-old monopoly of the Bell System. AT&T served as a vertically integrated end-to-end monopoly, providing almost all long-distance service and much of the local service in the United States. Its monopoly status was fully protected and regulated by the government. However, development of new microwave technology in the 1960s opened the doors to competition, with new companies like MCI entering the long-distance telephone market. AT&T tried its best to stifle competition using its vast resources and market power. This led to antitrust action and its historic breakup in 1984.

Prior to divestiture, research and development in the Bell System had been centralized at Bell Labs, which had established itself as one of the world's richest sources of private telecommunications research. With the divestiture of AT&T, Bell Labs was broken into AT&T Bell Labs and Bell Communications Research, Inc. (Bellcore). AT&T retained the former, while Bellcore met the needs of the divested Bell operating companies. The divestiture of AT&T raised concerns about the future of research and productivity in the telecom industry. It was feared that fragmentation of the Bell System would result in loss of economies of scale besides greatly limiting the scope and mission of Bell Labs.

Divestiture and Competition

Tables 1 and 2, respectively, show the pre- and postdivestiture market shares (4) of AT&T and other long-distance carriers. AT&T had complete monopoly over long-distance services until 1970, when for the first time the market was opened to competition. However, between 1970 and 1983, AT&T's market share fell only marginally, from 100% to 92% (an 8% decrease), as AT&T retained its incumbency advantages with complete control of the networks. Following divestiture, however, the decline in AT&T's market share was rather dramatic. Between 1984 and 1997, AT&T's share of long-distance market share fell from 90% to less than 45%, a loss of almost 50%. In addition, AT&T faced competition from resellers, whose numbers, according to Noam...

buda

Relationship to language

Many African languages are tonal languages, leading to a close connection between music and language in many African cultures. In singing, the tonal pattern or the text puts some constraints on the melodic patterns. On the other hand, in instrumental music a native speaker of a language can often perceive a text or texts in the music. This effect also forms the basis of drum languages (talking drums).

Africa

Main article: Talking drum

In Africa, New Guinea and the tropical America, natives used drum telegraphy to communicate with each other from far away for centuries. When European expeditions came into the jungles to explore the primeval forest, they were surprised to find that the message of their coming and their intention was carried through the woods a step in advance of their arrival.

Among the famous communication drums are the drums of West Africa (see talking drum). From regions known today as Nigeria and Ghana they spread across West Africa and to America and the Caribbean during the slave trade. There they were banned because they were being used by the slaves to communicate over long distances in a code unknown to their enslavers.

Talking drums were also used in East Africa and are described by Andreus Bauer in the 'Street of Caravans' while acting as security guard in the Wissmann Truppe for the caravan of Charles Stokes.

[edit]
        African drum language

The traditional drumming found in Africa is actually of three different types. Firstly, a rhythm can represent an idea (or signal). Secondly it can repeat the profile of a spoken utterance or thirdly it can simply be subject to musical laws.

Drum communication methods are not languages in their own right; they are based on actual natural languages. The sounds produced are conventionalized or idiomatic signals based on speech patterns. The messages are normally very stereotyped and context-dependent. They lack the ability to form new combinations and expressions.

In central and east Africa, drum patterns represent the stresses, syllable lengths and tone of the particular African language. In tone languages, where syllables are associated with a certain tone, some words are only distinguished only by their suprasegmental profile. Therefore, syllable drum languages can often communicate a message using the tonal phonemes alone.

In certain languages, the pitch of each syllable is uniquely determined in relation to each adjacent syllable. In these cases, messages can be transmitted as rapid beats at the same speed as speech as the rhythm and melody both match the equivalent spoken utterance.

Misinterpretations can occur due to the highly ambiguous nature of the communication. This is reduced by context effects and the use of stock phrases. For example, in Jabo, most stems are monosyllabic. By using a proverb or honorary title to create expanded versions of an animal, person's name or object, the corresponding single beat can be replaced with a rhythmic and melodic motif representing the subject. In practice not all listeners understand all of the stock phrases; the drum language is understood only to the level of their immediate concern.

Some peoples such as the Melanesians extend this idea further by freely inventing signs to make up their drum signals. This is in sharp contrast to the Efik tribe of Nigeria who use notes which exactly correspond to the tones of their morphemes. Different still is the Ewe language found in Togo, where only full sentences and their combinations are translated into the drum language. No smaller units are used; a sound picture represents a whole thought. This is similar to the Tangu tribe of New Guinea, where signals represent phrases, the mnemonics of which are parts of song melodies, quasi-poetic rhythms or purely personal rhythms.

When a drum is used in speech mode, it is culturally defined and depends on the linguistic/cultural boundaries. Therefore, communication suffers from translation problems as in vocal communication. There is no international drum language.

buda

In a night sky filled with hungry bats, good-tasting moths increase their chances of survival by mimicking the sounds of their bad-tasting cousins, according to a new Wake Forest University study.

Published in the May 29 issue of the Proceedings of the National Academy of Sciences, the study is the first to definitively show how an animal species uses acoustic mimicry as a defensive strategy.

The research was conducted by Jesse Barber, a doctoral student in biology at Wake Forest. William E. Conner, professor of biology at Wake Forest, co-authored the study.

In response to the sonar that bats use to locate prey, the tiger moths make ultrasonic clicks of their own. They broadcast the clicks from a paired set of structures called “tymbals.” Many species of tiger moth use the tymbals to make specific sounds that warn the bat of their bad taste. Other species make sounds that closely mimic those high-frequency sounds.

“We found that the bats do not eat the good-tasting moths that make the similar sounds,” said Barber, who has worked on this research for four years.

In the study, other types of moths that were similar in size to the sound-emitting moths, but did not make sounds, were gobbled up by the bats.

The researcher trained free-flying bats to hunt moths in view of two high-speed infrared video cameras to record predator-prey interactions that occur in fractions of a second. He also recorded the sounds emitted from each moth, as well as the sounds made by the bats.

All the bats quickly learned to avoid the noxious moths first offered to them, associating the warning sounds with bad taste. They then avoided a second sound-producing species even though it was not chemically protected. This is similar to the way birds avoid butterflies that look like the bad-tasting Monarch.

The two species of bats used were big brown bats and red bats. Barber raised the bats in the lab so behavior learned in the wild would not influence the results of the experiment.

Barber said anecdotal observations have suggested that animals such as snakes, owls and bees use acoustic mimicry. This study takes the next step and provides the definitive experimental evidence for how mimicking sounds helps an animal survive.

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beyond1128

感谢buda~~~

lyricsea

mm严重辛苦了。。。。

wjjdlq

感谢楼主！辛苦啦~