SWT# 43 Tree Rings

Here’s how tree ring dating, known to scientists as dendrochronology, works. If you cut a tree down today, it’s straightforward to count the rings inwards, starting from the tree’s outside. Hence the sequence of the rings in a tree cross-section is like a message in Morse code formerly used for sending telegraph messages; dot-dot-dash-dot-dash in the Morse code, wide-wide-narrow-wide-narrow in the tree ring sequence.

Actually, the tree ring sequence is even more diagnostic and richer in information than the Morse code, because trees actually contain rings spanning much different width, rather than the Morse code choice between dot and dash.

Tree ring specialists (known as dendrochronologists) proceed by noting the sequence of wider and narrower rings in a tree cut down in a known recent year, and also noting the sequences in beams from trees cut down at various times in the past. In that way, dendrochronologists have constructed tree ring records extending back for thousands of years in some parts of the world. A bonus of dendrochronology is that the width and substructure of each ring reflect the amount of rain and the season at which the rain fell during that particular year. Thus, tree ring studies also allow one to reconstruct the past climate.  

参考答案：（这道题信息比较细碎，同学们请注意合并文章的句子）

Tree ring dating is known to scientists as dendrochronology while the sequence of the rings in a tree cross-section is like a message in Morse code, and dendrochronologists have constructed tree ring records containing the sequence of wider and narrower rings in beams to reconstruct the past climate because such records reflect the amount of rain and the season at which the rain fell during that particular year.

秒懂逻辑：年轮的学习被称为树木年代学，年轮的信息就像摩斯密码一样。年轮学家可以通过年轮的宽展顺序去获得过去气候的信息，因为这些信息反应了当年的降雨量和季节。

SWT# 47 Double Blind

The feature of being “double blind”, where neither patients nor physicians are aware of who receives the experimental treatment, is almost universally trumpeted as being a virtue of clinical trials. Hence, trials that fail to remain successfully double blind are regarded as providing inferior evidential support. The rationale for this view is unobjectionable: double blinding rules out the potential confounding influences of patient and physician beliefs. Nonetheless, viewing double blind trial as necessarily superior is problematic. For one, it leads to the paradox that very effective experimental treatments will not be supportable by best evidence. If a new drug were to make even the most severe symptoms of the common cold disappear within seconds, most participants and investigators would correctly identify it as the latest wonder drug and not the control (i.e. placebo) treatment. Any trial testing the effectiveness of this wonder drug will therefore fail to remain double blind. Similar problems arise for treatments, such as exercise and most surgical techniques, whose nature makes them resistant to being tested in double blind conditions. It seems strange that an account of evidence should make priori judgments that certain claims can never be supported by ‘best evidence’. It would be different if the claims at issue were pseudoscientific – untestable. But so far as treatments with large effects go, the claim that they are effective is highly testable and intuitively should receive greater support from the evidence than do claims about treatments with moderate effects.

参考答案：

Double blind where neither patients nor physicians are aware of who receives the experimental treatment is almost universally trumpeted as being a virtue of clinical trials because double blinding rules out the potential confounding influences of patient and physician beliefs, but viewing double blind trial as necessarily superior is problematic because it leads to the paradox that very effective experimental treatments will not be supportable by best evidence, which should receive great support.

秒懂逻辑：该文章逻辑较为烦碎且信息量巨大，同学们一定要熟记。

双盲试验被广泛运用，因为它排除了病人和医生的主观因素，但是认为双盲试验更好是不对的，因为它会导致试验不能被其证据所证实悖论，而证据是应该收到更大的支持的。

SWT# 49 Khoikhoi

In around 2300 BP (Before Present), hunter gatherers called the San acquired domestic stock in what is now modern-day Botswana. Their population grew and spread throughout the Western half of South Africa. They were the first pastoralists in southern Africa, and called themselves Khoikhoi (or Khoe), which means 'men of men' or 'the real people'. This name was chosen to show pride in their past and culture. The Khoikhoi brought a new way of life to South Africa and to the San, who were hunter gatherers as opposed to herders. This led to misunderstandings and subsequent conflict between the two groups. The Khoikhoi were the first native people to come into contact with the Dutch settlers in the mid-17th century. As the Dutch took over land for farms, the Khoikhoi were dispossessed, exterminated, or enslaved and therefore their numbers dwindled. The Khoikhoi were called the ‘Hottentots’ by European settlers because the sound of their language was so different from any European language, and they could not pronounce many of the words and sounds.

参考答案：

Hunter gatherers called the San were the first pastoralists in southern Africa and called themselves Khoikhoi while the Khoikhoi brought a new way of life to the San and led to conflict between the two groups, and the Khoikhoi were the first native people to come into contact with the Dutch settlers whereas the Dutch, who called the Khoikhoi ‘Hottentots’, dwindled number of the Khoikhoi by dispossessing, exterminating, or enslaving.

秒懂逻辑：Khoikhoi人是非洲第一批牧民并且给非洲带来了冲突，他们也是第一批接触到荷兰人的人，但是荷兰人把他们几乎灭绝了，并且称他们为Hottentots。