mineral particles – AEAS精读 (Y10-12)

The mineral particles found in soil range in size from microscopic clay particles to large boulders. The most abundant particles — sand, silt, and clay — are the focus of examination in studies of soil texture. Texture is the term used to describe the composite sizes of particles in a soil sample, typically several representative handfuls. To measure soil texture, the sand, silt, and clay particles are sorted out by size and weight. The weights of each size are then expressed as a percentage of the sample weight. In the field, soil texture can be estimated by extracting a handful of soil and squeezing the damp soil into three basic shapes; (1) cast, a lump formed by squeezing a sample in a clenched fist; (2) thread, a pencil shape formed by rolling soil between the palms; and (3) ribbon, a flatfish shape formed by squeezing a small sample between the thumb and index finger. The behavioral characteristics of the soil when molded into each of these shapes, if they can be formed at all, provide the basis for a general textural classification. The behavior of the soil in the hand test is determined by the amount of clay in the sample. Clay particles are highly cohesive, and when dampened, behave as a plastic. Therefore the higher the clay content in a sample, the more refined and durable the shapes into which it can be molded. Another method of determining soil texture involves the use of devices called sediment sieves, screens built with a specified mesh size. When the soil is filtered through a group of sieves, each with a different mesh size, the particles become grouped in corresponding size categories. Each category can be weighed to make a textural determination. Although sieves work well for silt, sand, and larger particles, they are not appropriate for clay particles. Clay is far too small to sieve accurately; therefore, in soils with a high proportion of clay, the fine particles are measured on the basis of their settling velocity when suspended in water. Since clays settle so slowly, they are easily segregated from sand and silt. The water can be drawn off and evaporated, leaving a residue of clay, which can be weighed.





Shoemaker-Levy 9 – AEAS精读 (Y10-12)

In July of 1994, an astounding series of events took place. The world anxiously watched as, every few hours, a hurtling chunk of comet plunged into the atmosphere of Jupiter. All of the twenty-odd fragments, collectively called comet Shoemaker-Levy 9 after its discoverers, were once part of the same object, now dismembered and strung out along the same orbit. This cometary train, glistening like a string of pearls, had been first glimpsed only a few months before its fateful impact with Jupiter, and rather quickly scientists had predicted that the fragments were on a collision course with the giant planet. The impact caused an explosion clearly visible from Earth, a bright flaming fire that quickly expanded as each icy mass incinerated itself. When each fragment slammed at 60 kilometers per second into the dense atmosphere, its immense kinetic energy was transformed into heat, producing a superheated fireball that was ejected back through the tunnel the fragment had made a few seconds earlier. The residues from these explosions left huge black marks on the face of Jupiter, some of which have stretched out to form dark ribbons.

Although this impact event was of considerable scientific import, it especially piqued public curiosity and interest. Photographs of each collision made the evening television newscast and were posted on the Internet. This was possibly the most open scientific endeavor in history. The face of the largest planet in the solar system was changed before our very eyes. And for the very first time, most of humanity came to fully appreciate the fact that we ourselves live on a similar target, a world subject to catastrophe by random assaults from celestial bodies. That realization was a surprise to many, but it should not have been. One of the great truths revealed by the last few decades of planetary exploration is that collisions between bodies of all sizes are relatively commonplace, at least in geologic terms, and were even more frequent in the early solar system.




Clinical nutrition – AEAS精读 (Y10-12)

The history of clinical nutrition, or the study of the relationship between health and how the body takes in and utilizes food substances, can be divided into four distinct eras: the first began in the nineteenth century and extended into the early twentieth century when it was recognized for the first time that food contained constituents that were essential for human function and that different foods provided different amounts of these essential agents. Near the end of this era, research studies demonstrated that rapid weight loss was associated with nitrogen imbalance and could only be rectified by providing adequate dietary protein associated with certain foods.

The second era was initiated in the early decades of the twentieth century and might be called “the vitamin period.” Vitamins came to be recognized in foods, and deficiency syndromes were described. As vitamins became recognized as essential food constituents necessary for health, it became tempting to suggest that every disease and condition for which there had been no previous effective treatment might be responsive to vitamin therapy. At that point in time, medical schools started to become more interested in having their curricula integrate nutritional concepts into the basic sciences. Much of the focus of this education was on the recognition of vitamin deficiency symptoms. Herein lay the beginning of what ultimately turned from ignorance to denial of the value of nutritional therapies in medicine. Reckless claims were made for effects of vitamins that went far beyond what could actually be achieved from the use of them.

In the third era of nutritional history in the early 1950’s to mid-1960s, vitamin therapy began to fall into disrepute. Concomitant with this, nutrition education in medical schools also became less popular. It was just a decade before this that many drug companies had found their vitamin sales skyrocketing and were quick to supply practicing physicians with generous samples of vitamins and literature extolling the virtue of supplementation for a variety of health-related conditions. Expectations as to the success of vitamins in disease control were exaggerated. As is known in retrospect, vitamin and mineral therapies are much less effective when applied to health-crisis conditions than when applied to long-term problems of undernutrition that lead to chronic health problems.





Aurora – AEAS精读 (Y10-12)

The spectacular aurora light displays that appear in Earth’s atmosphere around the north and south magnetic poles were once mysterious phenomena. Now, scientists have data from satellites and ground-based observations from which we know that the aurora brilliance is an immense electrical discharge similar to that occurring in a neon sign. To understand the cause of auroras, first picture the Earth enclosed by its magnetosphere, a huge region created by the Earth’s magnetic field. Outside the magnetosphere, blasting toward the earth is the solar wind, a swiftly moving plasma of ionized gases with its own magnetic filed. Charged particles in this solar wind speed earthward along the solar wind’s magnetic lines of force with a spiraling motion. The Earth’s magnetosphere is a barrier to the solar winds, and forces the charged particles of the solar wind to flow around the magnetosphere itself. But in the polar regions, the magnetic lines of force of the Earth and of the solar wind bunch together. Here many of the solar wind’s charged particles break through the magnetosphere and enter Earth’s magnetic field. They then spiral back and forth between the Earth’s magnetic poles very rapidly. In the polar regions, electrons from the solar wind ionize and excite the atoms and molecules of the upper atmosphere, causing them to emit aurora radiations of visible light. The colors of an aurora depend on the atoms emitting them. The dominant greenish white light comes from low energy excitation of oxygen atoms. During huge magnetic storms oxygen atoms also undergo high energy excitation and emit crimson light. Excited nitrogen atoms contribute bands of color varying from blue to violet. Viewed from outer space, auroras can be seen as dimly glowing belts wrapped around each of the Earth’s magnetic poles. Each aurora hangs like a curtain of light stretching over the polar regions and into the higher latitudes. When the solar flares that result in magnetic storms and aurora activity are very intense, aurora displays may extend as far as the southern regions of the United States. Studies of auroras have given physicists new information about the behavior of plasmas, which has helped to explain the nature of outer space and is being applied in attempts to harness energy from the fusion of atoms.






AEAS精读:Social Media Privacy – A Contradiction in Terms?

This article is by Naomi Troni, global CMO of Euro RSCG Worldwide.

Never in the course of human interaction have so many shared so much about themselves with so many others – and with so little apparent concern for their privacy. Was it really just a generation ago that people kept all but their most basic information under virtual lock and key? Today, we happily share our date and place of birth, name of our first pet, mother’s maiden name, favourite movie or book, favourite colour, first school teacher – and myriad other snippets of information required by online services as part of their security procedures.

The basic premise behind this information-sharing is nothing new. Consumers have long handed over a little personal information in exchange for services such as banking and finance, utilities and healthcare. The big difference now is that the information is digitized and accessible online – and we’re handing it out to virtually anyone who asks, regardless of how briefly the business has been in existence. Of even greater concern to many is the amount and variety of information being gathered about us without our explicit permission. Whereas retailers and others used to tweeze out information gleaned through loyalty cards, prize draws and catalogue mailing lists, now these old standbys have been massively augmented by customers researching and purchasing online, leaving in their wake a digital trail of cookie crumbs detailing their needs, tastes and desires.

And then there’s social media. If this isn’t the Holy Grail* for marketers, it’s difficult to imagine what would be. In this thoroughly 21st century communications channel, old notions of privacy simply do not apply; sharing personal information, experiences and opinions is the whole point of the service. And, wonder of wonders, consumers don’t only provide it willingly – they provide it for free’ Sure, some people take the precaution of limiting access to their Facebook or Google+ pages, but even these people typically are eager to share their thoughts via comment sections on news sites, reviews on retail sites and in branded clubs and forums.

With all the time we spend online and all the forums we frequent, it’s no wonder most of us have grown accustomed to doling out little snippets of personal information with barely a second thought. It helps that we rarely are asked to hand over a whole stack of personal information in one massive data transfer; that would be too much trouble and might provoke too much anxiety. Rather, we routinely hand it out a bit at a time.

Anybody over the age of 30 likely will remember that in the early days of mainstream Internet, 10 to 15 years ago, consumers were wary about handing over private information. A 2001 UCLA report, for instance, found high levels of consumer concern over online privacy in general and credit card security in particular.

Since then hundreds of millions of people have come online and become regular users of commerce sites and social media. Early concerns about online privacy have been sidelined by the desire for more speed, more convenience, more choice and more great deals. Familiarity has bred complacency and even foolhardiness; we’ve all heard about people uploading pretty much everything, including the most intimate words and images.

Now, after a decade of consumers feeling increasingly free-and-easy with their personal information online, we are seeing signs of a new wariness setting in. In a Euro RSCG global survey conducted among 7,213 adults in 19 countries, we found that 55% of respondents are worried that ‘technology is robbing us of our privacy’; the figure was above 60% in a number of countries, including the United States and China. Similarly, 61 % overall agreed ‘People share too much about their personal thoughts and experiences online; we need to go back to being more private.’

And it’s not just snooping companies and hackers that consumers fear. Nearly half the sample (47%) – and a majority of millennials* – worry that friends or family will share inappropriate personal information about them online. Around one-third overall already regret posting personal information about themselves.

* Holy Grail – a desired ambition or goal (in Christian tradition, the cup used by Jesus at the Last Supper with his followers)
* Millennials – people born between 1982 and 2000

Colonial – AEAS精读 (Y10-12)

Although only 1 person in 20 in the Colonial period lived in a city, the cities had a disproportionate influence on the development of North America. They were at the cutting edge of social change. It was in the cities that the elements that can be associated with modern capitalism first appeared — the use of money and commercial paper in place of barter, open competition in place of social deference and hierarchy, with an attendant rise in social disorder, and the appearance of factories using coat or water power in place of independent craftspeople working with hand tools. “The cities predicted the future,” wrote historian Gary. B. Nash, “even though they were but overgrown villages compared to the great urban centers of Europe, the Middle East and China.”

Except for Boston, whose population stabilized at about 16,000 in 1760, cities grew by exponential leaps through the eighteenth century. In the fifteen years prior to the outbreak of the War for independence in 1775, more than 200,000 immigrants arrived on North American shores. This meant that a population the size of Boston was arriving every year, and most of it flowed into the port cities in the Northeast. Philadelphia’s population nearly doubted in those years, reaching about 30,000 in 1774, New York grew at almost the same rate, reaching about 25,000 by 1775.

The quality of the hinterland dictated the pace of growth of the cities. The land surrounding Boston had always been poor farm country, and by the mid-eighteenth century it was virtually stripped of its timber. The available farmland was occupied, there was little in the region beyond the city to attract immigrants. New York and Philadelphia, by contrast, served a rich and fertile hinterland laced with navigable watercourses. Scots, Irish, and Germans landed in these cities and followed the rivers inland. The regions around the cities of New York and Philadelphia became the breadbaskets of North America, sending grain not only to other colonies but also to England and southern Europe, where crippling droughts in the late 1760’s created a whole new market.




Cties – AEAS精读 (Y10-12)

Throughout the nineteenth century and into the twentieth, citizens of the United States maintained a bias against big cities. Most lived on farms and in small towns and believed cities to be centers of corruption, crime, poverty, and moral degradation. Their distrust was caused, in part, by a national ideology that proclaimed farming the greatest occupation and rural living superior to urban living. This attitude prevailed even as the number of urban dwellers increased and cities became an essential feature of the national landscape. Gradually, economic reality overcame ideology. Thousands abandoned the precarious life on the farm for more secure and better paying jobs in the city. But when these people migrated from the countryside, they carried their fears and suspicious with them. These new urbanities, already convinced that cities were overwhelmed with great problems, eagerly embraced the progressive reforms that promised to bring order out of the chaos of the city.

One of many reforms came in the area of public utilities. Water and sewerage systems were usually operated by municipal governments, but the gas and electric networks were privately owned. Reformers feared that the privately owned utility companies would charge exorbitant rates for these essential services and deliver them only to people who could afford them. Some city and state governments responded by regulating the utility companies, but a number of cities began to supply these services themselves. Proponents of these reforms argued that public ownership and regulation would insure widespread access to these utilities and guarantee a fair price.

While some reforms focused on government and public behavior, others looked at the cities as a whole. Civic leaders, convinced that physical environment influenced human behavior, argued that cities should develop master plans to guide their future growth and development. City planning was nothing new, but the rapid industrialization and urban growth of the late nineteenth century took place without any consideration for order. Urban renewal in the twentieth century followed several courses. Some cities introduced plans to completely rebuild the city core. Most other cities contented themselves with zoning plans for regulating future growth. Certain parts of town were restricted to residential use, while others were set aside for industrial or commercial development.





Sculpture – AEAS精读 (Y10-12)

The sculptural legacy that the new United States inherited from its colonial predecessors was far from a rich one, and in fact, in 1776 sculpture as an art form was still in the hands of artisans and craftspeople. Stone carvers engraved their motifs of skulls and crossbones and other religious icons of death into the gray slabs that we still see standing today in old burial grounds. Some skilled craftspeople made intricately carved wooden ornamentations for furniture or architectural decorations, while others caved wooden shop signs and ships’ figureheads. Although they often achieved expression and formal excellence in their generally primitive style, they remained artisans skilled in the craft of carving and constituted a group distinct from what we normally think of as “sculptors” in today’s use of the word.

On the rare occasion when a fine piece of sculpture was desired, Americans turned to foreign sculptors, as in the 1770’s when the cities of New York and Charleston, South Carolina, commissioned the Englishman Joseph Wilton to make marble statues of William Pitt. Wilton also made a lead equestrian image of King George III that was created in New York in 1770 and torn down by zealous patriots six years later. A few marble memorials with carved busts, urns, or other decorations were produced in England and brought to the colonies to be set in the walls of churches — as in King’s Chapel in Boston. But sculpture as a high art, practiced by artists who knew both the artistic theory of their Renaissance-Baroque-Rococo predecessors and the various technical procedures of modeling, casting, and carving rich three-dimensional forms, was not known among Americans in 1776. Indeed, for many years thereafter, the United States had two groups from which to choose — either the local craftspeople or the imported talent of European sculptors.

The eighteenth century was not one in which powered sculptural conceptions were developed. Add to this the timidity with which unschooled artisans — originally trained as stonemasons, carpenters, or cabinetmakers — attacked the medium from which they sculpture made in the United States in the late eighteenth century.




Fireplace – AEAS精读 (Y10-12)

In seventeenth-century colonial North America, all day-to-day cooking was done in the fireplace. Generally large, fireplaces were planned for cooking as well as for warmth. Those in the Northeast were usually four or five feet high, and in the South, they were often high enough for a person to walk into. A heavy timber called the mantel tree was used as a lintel to support the stonework above the fireplace opening. This timber might be scorched occasionally, but it was far enough in front of the rising column of heat to be safe from catching fire.

Two ledges were built across from each other on the inside of the chimney. On these rested the ends of a “lug pole” from which pots were suspended when cooking. Wood from a freshly cut tree was used for the lug pole, so it would resist heat, but it had to be replaced frequently because it dried out and charred, and was thus weakened. Sometimes the pole broke and the dinner fell into the fire. When iron became easier to obtain, it was used instead of wood for lug poles, and later fireplaces had pivoting metal rods to hang pots from.

Beside the fireplace and built as part of it was the oven. It was made like a small, secondary fireplace with a flue leading into the main chimney to draw out smoke. Sometimes the door of the oven faced the room, but most ovens were built with the opening facing into the fireplace. On baking days (usually once or twice a week) a roaring fire of “oven wood,” consisting of brown maple sticks, was maintained in the oven until its walls were extremely hot. The embers were later removed, bread dough was put into the oven, and the oven was sealed shut until the bread was fully baked.

Not all baking was done in a big oven, however. Also used was an iron “bake kettle,” which looked like a stewpot on legs and which had an iron lid. This is said to have worked well when it was placed in the fireplace, surrounded by glowing wood embers, with more embers piled on its lid.


在十七世纪的北美殖民地,所有的日常烹饪都在壁炉里完成。通常很大,壁炉计划用于烹饪和保暖。在东北部的人通常是四到五英尺高,在南部,他们往往足够高,一个人可以走进去。一块称为壁炉架的重型木材被用作门楣,以支撑壁炉开口上方的石雕。这种木材偶尔可能会被烧焦,但在升高的热柱前面足够远,以防止着火。    两个壁架在烟囱内部相互对接。在这些上面放置一个“凸耳杆”的末端,在烹饪时悬挂盆。来自刚切割的树木的木材用于凸耳杆,因此它会抵抗热量,但它必须经常更换,因为它干燥并烧焦,因此被削弱。有时杆子坏了,晚餐掉进火里。当铁变得更容易获得时,它被用来代替木头用于吊耳杆,后来的壁炉有旋转金属杆来悬挂罐子。    在壁炉旁边,它是烤箱的一部分。它被制成一个小型的二级壁炉,烟道通向主烟囱抽出烟雾。有时烤箱的门面向房间,但大多数烤箱都是在面向壁炉的开口处建造的。在烘烤日(通常每周一次或两次),在烤箱中保持由“棕色枫木棒”组成的“烤炉木”的咆哮火,直到其壁非常热。随后取出余烬,将面包面团放入烤箱中,将烤箱密封,直至面包完全烘烤。    然而,并非所有烘焙都是在大烤箱中进行的。还使用了一个铁“烘烤水壶”,看起来像腿上的炖锅,并有一个铁盖。据说它放在壁炉里时效果很好,周围是发光的木制余烬,盖子上堆着更多的余烬。

Colonies – AEAS精读 (Y10-12)

The principal difference between urban growth in Europe and in the North American colonies was the slow evolution of cities in the former and their rapid growth in the latter. In Europe they grew over a period of centuries from town economies to their present urban structure. In North America, they started as wilderness communities and developed to mature urbanism in little more than a century.
In the early colonial days in North America, small cities sprang up along the Atlantic Coastline, mostly in what are now New England and Middle Atlantic states in the United States and in the lower Saint Lawrence valley in Canada. This was natural because these areas were nearest to England and France, particularly England, from which most capital goods (assets such as equipment) and many consumer goods were imported. Merchandising establishments were, accordingly, advantageously located in port cities from which goods could be readily distributed to interior settlements. Here, too, were the favored locations for processing raw materials prior to export. Boston, Philadelphia, New York, Montreal, and other cities flourished, and, as the colonies grew, these cities increased in importance.
This was less true in the colonial South, where life centered around large farms, known as plantations, rather than around towns, as was the case in the areas further north along the Atlantic coastline. The local isolation and the economic self-sufficiency of the plantations were antagonistic to the development of the towns. The plantations maintained their independence because they were located on navigable streams and each had a wharf accessible to the small shipping of that day. In fact, one of the strongest factors in the selection of plantation land was the desire to have its front on a water highway.
When the United States became an independent nation in 1776, it did not have a single city as large as 50,000 inhabitants, but by 1820 it had a city of more than 10,000 people, and by 1880 it had recorded a city of over one million. It was not until after 1823, after the mechanization of the spinning had weaving industries, that cities started drawing young people away from farms. Such migration was particularly rapid following the Civil War (1861-1865).


欧洲城市增长与北美殖民地之间的主要差异在于前者城市的缓慢演变以及后者城市的快速增长。在欧洲,他们在几个世纪的时间里从城镇经济发展到现在的城市结构。在北美,它们起初是荒野社区,并在一个多世纪的时间里发展成为成熟的都市主义。    在北美早期的殖民时期,小城市沿着大西洋海岸线兴起,大部分位于美国现在的新英格兰和中大西洋各州以及加拿大的圣劳伦斯河谷下游。这很自然,因为这些地区离英格兰和法国最近,特别是英格兰,大多数资本货物(设备等资产)和许多消费品都是从这些地区进口的。因此,商品销售场所有利地位于港口城市,货物可以从那里容易地分配到内部定居点。这里也是出口前加工原料的首选地点。波士顿,费城,纽约,蒙特利尔和其他城市蓬勃发展,随着殖民地的增长,这些城市的重要性也在增加。在殖民地南方,这种情况不那么真实,那里的生活集中在大型农场,即种植园,而不是城镇周围,就像沿大西洋海岸线向北的地区一样。种植园的局部隔离和经济自给自足与城镇的发展相对立。种植园保持了独立性,因为它们位于可通航的溪流中,每个都有一个码头可供当天的小型运输。事实上,选择种植园土地的最重要因素之一是希望在水上高速公路上占据一席之地。    当美国在1776年成为一个独立的国家时,它没有一个拥有5万居民的单一城市,但是到1820年,它拥有一个超过10,000人的城市,并且到1880年它已经记录了一个超过一百万的城市。直到1823年之后,在纺纱机械化织造工业之后,城市开始吸引年轻人远离农场。在南北战争(1861-1865)之后,这种迁移特别迅速。