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Bài luận sinh học - Đọc, dịch và phân tích


Tôi vừa tìm thấy trang này, nơi chứa các bài luận sinh học dành cho sinh viên học môn Sinh học Đại cương ở một trường ĐH Mỹ. Sỡ dĩ tui giới thiệu trang web này ở mục Tiếng Anh chuyên ngành vì các lý do sau:

01-Dĩ nhiên là các bài luận viết bằng English do SV bản xứ viết. Nội dung ở mức đại cương do đó việc đọc và dịch hoàn toàn nằm trong tầm tay của bất kỳ sinh viên sinh học nào.

02- Thông qua các bài luận,  chúng ta có thể thấy  cách thức viết, trình bày, lập luận, trích dẫn của SV như thế nào. Rất giản dị nhưng rất hiệu quả. Nó khác với việc viết "tràng giang đại hải" của SV VN nhưng hiệu quả không là bao.

03- Qua việc đọc và dịch, chúng ta có thể tham gia phân tích mổ xẻ điểm được và chưa được của bài luận (cả Anh lẫn Việt) về mọi khía cạnh; từ đó tránh được các lỗi sơ đẳng khi viết lách.

04- Những bản dịch tiếng Việt có thể dùng làm tài liệu cho SHVN về lâu dài.

Để bắt đầu tuần này ta thử xem hai bài dưới đây và mời các anh chị em cùng ra tay "vật" nó, anh chị có thể tìm bài khác mà anh chị ưng ý trong list các bài. Sau đó chúng cùng chỉnh sửa, phân tích và học tập:

a- lỗi dịch
b- các đặt vấn đề, triển khai, tìm lý lẽ, dẫn chứng.
c- hàm lượng khoa học, tài liệu tham khảo.
d- bài học cho riêng chúng ta?


Bioinformatics: The Gold Rush of Today
Nimia Barrera

"Plastics." When a family friend whispered this word to Dustin Hoffman's character in the 1967 film The Graduate, he was advocating not just a novel career choice but an entirely different way of life. If that movie were made today, in the age of the deciphering of the human genome, the magic word might well be "bioinformatics" (1).

Bioinformatics is the application of computer technology to the management of biological information. Computers are used to gather, store, analyze and integrate biological and genetic information, which can then be applied to gene-based drug discovery and development (2). The need for Bioinformatics capabilities has been precipitated by the explosion of publicly available genomic information resulting from the Human Genome Project (HGP). The goal of this project - determination of the sequence of the entire human genome (approximately three billion base pairs) - will be reached by the year 2002. The science of Bioinformatics, which is the melding of molecular biology with computer science, is essential to the use of genomic information in understanding human diseases and in the identification of new molecular targets for drug discovery. In recognition of this, many universities, government institutions, and pharmaceutical firms have formed bioinformatics groups, consisting of computational biologists and bioinformatics computer scientists(2). Such groups will be key to unraveling the mass of information generated by large scale sequencing efforts underway in laboratories around the world.

Companies from all around are vying for their share in this "bioinformatics gold rush." Jason Reed of the investment banking firm Oscar Gruss & Son in New York estimates that bioinformatics could be a $2-billion business within five years (1). The reason companies are so willing to invest in research and resource services of bioinformatics is that bioinformatics offers the opportunity of finding better drug targets earlier in the drug development process. "Assume I'm a pharmaceutical company and somebody can get [my] drug to the market one year sooner," explains Stelios Papadopoulous, managing director of health care at New York investment banking firm SG Cowen. "It could mean you could grab maybe $500 million in sales you would not have recovered" (1).

One of the most basic operations in bioinformatics involves searching for similarities, or homologies, between a newly sequenced piece of DNA and previously sequenced DNA segments from various organisms. Finding near-matches allows researchers to predict the type of protein the new sequence encodes. This not only yields leads for drug targets early in drug development but also weeds out many targets that would have turned out to be dead ends.

A popular set of software programs for comparing DNA sequences is BLAST (Basic Local Alignment Search Tool). The BLAST programs have been designed for speed, with a minimal sacrifice of sensitivity to distant sequence relationships. The scores assigned in a BLAST search have a well-defined statistical interpretation, making real matches easier to distinguish from random background hits (3).

The revolution of Bioinformatics involves many different players with different strategies. The various companies cater to different needs. Some cater to large users, aiming their services and products at genomics, biotechnology, and pharmaceutical companies by creating custom software and offering consulting services.

It all adds up to good days ahead for bioinformatics, which many assert holds the real promise of genomics. "Genomics without bioinformatics will not have much of a payoff," states Roland Somogyi, former director of neurobiology at Incyte Genomics (2). Michael N. Liebman, head of computational biology at Roche Bioscience in Palo Alto, agrees. "Genomics is not the paradigm shift; it's understanding how to use it that is the paradigm shift," he asserts. "In bioinformatics, we're at the beginning of the revolution" (2).

WWW Sources
1)The Bioinformatics Gold Rush, Scientific American Article
2)What is Bioinformatics?, Ask Jeeves Result
3)BLAST Overview, NCBI Website

Do Human Pheromones Really Exist?

Meghan McCabe

What is it that attracts people to each other? Nice hair? Big muscles? Body scent? Recent studies have shown that the cause of such sexual attractions could be airborne chemicals called pheromones, airborne and odorless molecules "emitted by an individual and cause changes in physiology and/or behavior of another individual" (8 ). Pheromones, which have been known to influence sexual activity, aggression, and territory marking, have been found in many animals, including amoebas, fish, hamsters, and monkeys (3). However, whether or not these chemicals affect, or even exist in humans, has been a subject for debate in the scientific community. Since pheromones are not detectable by the human sense of smell, scientists believe that pheromones are sensed by the vomeronasal organ (VNO), part of the olfactory system and located inside the mouth or nose (9). For many years, the existence of the VNO produced much speculation because it had only been found occasionally in adult humans, and when it was found, it was believed to be vestigial. However, in 1985 a study was conducted in which the noses of 100 human adults were examined post-mortem. The VNO was found in the septums of 70% of those examined. Since 1985, much evidence has been gathered to suggest the presence of the VNO in most adult humans (2), but many scientists still believe it to be a functionless organ that was inherited from some ancestor of humans. However, recent genetic research has shown the possibility of a receptor in the nose that could sense pheromones. When searching the human genome for genes that had similar sequences to those of rodent pheromone receptors, scientists found one gene that could produce a pheromone receptor, and when searching olfactory tissue from the human nose, they found this receptor (5).

In the past few years researchers have believed to have found scientific proof that "humans have the potential to communicate pheromonally, either by using an unidentified part of the main olfactory system, or perhaps with a sixth sense, with its own unique pathway (1)." One study was based on the observation that women living together develop synchrony of menstrual cycles. In this study, researchers placed gauze pads under the armpits (a body part where pheromones are believed to be secreted in the sweat) of nine women during specific phases of their menstrual cycle. They each wore the pads for at least eight hours. After being treated with alcohol and frozen, the pads were placed under the noses of twenty other women. The women that sniffed the pads of the women that had been in the preovulatory phase of their cycle found that their own menstrual cycles were shortened from one to fourteen days. The women that sniffed the pads of the women that had been in the ovulation phase if their menstrual cycles found that their own cycles were lengthened from one to twelve days (1). This suggests that there are substances or chemicals released from women that can accelerate or delay menstrual cycles (4), which influence the release of eggs (10), and thus lead to synchrony of cycles of women living in proximity. However, since the substances from the pads were placed on the upper lip, it is difficult to say how these women sensed them, "whether it's through skin, the mucous membranes in the nose, or the VNO (9)."

Another study shows that babies prefer clothing worn by their own mothers. In this study, ten mothers were asked to wear a cotton pad in their bras for three hours. The pads were then given to their babies to see whether or not they could distinguish between the pads worn by their mothers and those worn by strangers. At the age of six weeks, eight babies had responded by sucking to their mother's pad, one responded to a stranger's pad, and one did not react to its mothers pad, but reacted with a cry to a stranger's pad (3). Researchers believe this could suggest that men and women choose their mates by sniffing out those that have "compatible immune systems (9)."

Some researchers believe that there is a relationship between physical attractiveness and body odor. In a study to test this hypothesis, 16 males and 19 females were asked to wear a t-shirt on three consecutive nights without using any perfumes or deodorants. Fifteen more subjects each smelled a t-shirt of the opposite sex, rating its scent on pleasantness and sexiness. Another group of 22 men and women were asked to rate the subjects that wore the t-shirts in terms of physical attractiveness. The results showed a correlation between facial attractiveness and sexiness of body odor of females. However, there was only a correlation between facial attractiveness and sexiness of body odor of males when females raters were in "their most fertile phase of menstrual cycle (day 5 to 16) (6)." Nevertheless, this study does suggest a relationship between physical attractiveness and attractiveness of body odor.

A similar study attempted to find out whether or not males can sense ovulation by smelling copulins, fatty acids in vaginal secretions. Males smelled copulin samples from women who were in three different phases of the menstrual cycle. The results showed that males generally could not distinguish between a pre-menstrual, menstrual, and ovulatory scents. However, the males also rated the physical attractiveness of the females, and results showed that females were rated more attractive when the males were smelling their copulins then when they were weren't, and that their testosterone levels increased when they were smelling the copulins (7).

This research strongly suggests the presence of chemicals that cause changes in non-conscious behavior. In my research, I mostly found information that discussed scents that females produce that attract males or offspring, such as copulins, or chemicals that affect the menstrual cycle. This is interesting because it supports the old stereotype that in nature males search out females as mates and not vice versa. The existence of the VNO in females might suggest otherwise, but it should be a topic for greater research. I was also a bit wary of the studies that involved the rating of physical attractiveness, simply because attractiveness is so relative. In any case, my research suggests that sexual receptivity is based on more than attractiveness of physical features.

WWW Sources
1) University of Chicago News
2) Human Pheromones

3) Pheromones in Humans: Myth or Reality

4) Human Pheromones

5) Academic Press Daily InScight

6)Ludwig-Boltzmann-Institute for Urban Etholo

7) Ludwig-Boltzmann-Institute for Urban Ethology

8 ) Ludwig-Boltzmann-Institute for Urban Ethology

9) Sniffing Out Human Pheromones

10) Health Story Page

Continuing conversation
(to contribute your own observations/thoughts , write Serendip)

06/15/2005, from a Reader on the Web
I was pleased to find your article. I am a teacher. Many colleagues note that boys' school washrooms smell badly. They know there is often trouble around these areas. I should be interested to know if any research has been carried out in this field. Years ago I read about male pheromones in urine. Thus, territory marking is involuntary, and seems not to have been taken into account by architects. Boys' washrooms do not always get hosed down daily, as their design does not allow for drainage. This means that if a central drain were placed in the middle of the floor, enabling these areas to be hosed down daily, the pheromones could be flushed away. This could reduce the instances of aggressive behaviours. I do not know whether public buildings have a regulation to prevent this type of drainage, or whether there is insufficient information on the connection between the presence of pheromones in male urine and aggression. Mary Saunders santinavitalis@gmail.com