决定佛里德里希共济失调GAA/TTC扩增的途径被确定 引自美国SCIENCEDAILY(米国科学日报） 米国佐治亚理工大学的研究人员发现，决定佛里德里希共济失调GAA/TTC扩增得基因多达33个，显然这似乎也是一个多基因决定的数量遗传。但是，如此众多的基因对患者基因组上特定位点的GAA/TTC扩增的具有影响，而不是对整个基因组内所有GAA/TTC重复序列都具有影响，这很让人费解。 众多基因针对特定基因座内的GAA/TTC重复序列产生影响，而不是对基因组范围内的所有同类重复序列的稳定性产生影响不合情理。尽管如此，此文发表在去年的著名杂志《分子细胞》上。该项研究由美国NIH和国家自然科学基金共同支持，但相同的工作却得不到中国国家自然科学基金的支持。 笔者为争取中国国家自然科学基金的支持，在长达7~8年时间里连续申请中国国家自然科学基金均没有成功。 这也反映了中国和米国“国家自然科学基金”的眼界和高度据有明显的差异。 Sep. 10, 2012 — A study of more than 6,000 genes in a common species of yeast has identified the pathways that govern the instability of GAA/TTC repeats. In humans, the expansions of these repeats is known to inactivate a gene -- FXN -- which leads to Friedreich's ataxia, a neurodegenerative disease that is currently incurable. In yeast, long repeats also destabilize the genome, manifested by the breakage of chromosomes. Working with collaborators at Tufts University, researchers at the Georgia Institute of Technology identified genetic deficiencies associated with the instability of the repeats in four different classes of genes that control replication, transcription initiation, checkpoint response and telomere maintenance. They were surprised to find that the GAA/TTC repeats could promote gene expression in yeast, suggesting that the repeats may play both positive and negative roles in cells. While the study examined the repeat metabolisms in the yeast Saccharomyces cerevisiae , the researchers believe their discoveries may have implications for human disease because many components of genetic machinery have been conserved in evolution. The study was reported online Sept. 6 in the journal Molecular Cell . The research was supported by the National Institutes of Health (NIH) and the National Science Foundation (NSF ). The expansions occur in GAA/TTC sequences located on the FXN gene that plays a vital role in cell metabolism. Patients with Friedreich's ataxia can have as many as 1,700 copies of the nucleotide sequence, compared to fewer than 65 copies in individuals without the genetic expansion. Although not yet observed in humans, in yeast the expanded repeats can cause chromosomal fragility, which -- despite cellular repair mechanisms -- can produce errors resulting in dramatic genomic rearrangements. "How these expansions happen is a very mysterious process, and we do not know why some people get the disease and some people do not," said Kirill Lobachev, an associate professor in Georgia Tech's School of Biology. "We are trying to develop a simplistic way to determine what individuals may be predisposed to the disease and to find the genotypes where these expansions occur with great frequency." At the core of the study was detailed screening of the yeast's entire genome, some 6,000 genes in all. Conducted by graduate research assistant Yu Zhang, the exhaustive assay identified 33 genes associated with the repeats fragility and expansions. The connection between genomic expansion and genes that initiate transcription came as a surprise. "We found that these repeats can recruit transcription initiation factors and induce transcription," said Lobachev. "The repeats seem to work as non-traditional promoters for an abnormal type of transcription. It turns out that this ability to drive transcription is a significant factor in their instability. That makes this a more complicated story for sure, however, it also opens new avenues to examine the repeats." The ability of the repeats to affect the activity of genes may indicate a broader effect on the genome, and if the effect is also seen in humans, could account for some of the subtle differences between individuals. "By some estimates, there may be a thousand locations in our chromosomes where these repeats can expand," said Lobachev. "Probably each person differs in the number of repeats in specific locations. This is important because of their ability to change gene expression." Among the next steps in the research is to determine how the expansions occur in cells that aren't dividing, such as neurons. The genetic mechanisms involved in cell replication offer clear opportunities for repeat expansions, but the mechanism for repeat amplification in non-dividing cells remains a mystery. The researchers believe the finding that GAA/TTC repeats can promote transcription provides clues for understanding what is going on in terminally differentiated cells. Why repeats with the detrimental ability to expand have remained a part of the genomes also remains a question. Genetic processes that hinder an organism's competitiveness are normally eliminated during the process of evolution. "Perhaps these repeats play a positive role in the cell when they are small, but because of their ability to expand, they sometimes get out of control and become larger," Lobachev said. The findings reported in the yeast, which is commonly used in wine-making and brewing, may help chart a new course in human studies. Scientists often begin genetic research with simpler organisms such as yeast, and use the findings to provide direction for examining similar mechanisms in humans. "A lot of the processes that are going on in our cells and in yeast cells are the same," Lobachev noted. "These processes are highly conserved throughout evolution. The history of biology tells us that most probably what we find in yeast is going to turn out to be true in humans." Lobachev hopes the study will lead to new research, both in yeast genetics and humans. "We have built a map for future analysis so that when people sequence the genome and find deficiencies in particular genes, that will be a clear prediction that individuals with those deficiencies will be predisposed to instability," Lobachev said. "There are now several directions for us and other labs to pursue to see what is really happening here. In addition to those already mentioned, the study's authors also included Alexander Shishkin, Dana Marcinkowski-Desmond and Sergei Mirkin from Tufts University, and Yuri Nishida, Natalie Saini and Kirill Volkov from Georgia Tech.
This time, it is really about common sense. I stayed home on Monday, though I went to work briefly after 4 pm (so I could park near my office) to refine a model parameter . I took the Election Day off on Tuesday, and stayed home on Wednesday again. When I finally went to work at lunch time today, I found a strange "welcome." I showed up at my office after lunch, and said hello to my "office mates." Then, I went to my computer, to get some work done. M y mind was on something, my research, but distractions came again and again. I had to deal with one a fte r another truly stupid question, about office space or luncheon , and I was getting irritated . Oh, Lord. Wher e is the common sense? Didn't your mother ever t e ll you to say nothing IF you can't say something nice???
No, this is actually NOT about common sense , to th ink about it again. A NEW client came to me, with a manuscript coauthored by two people, WHO and HU. I knew HU very well, since he is a good friend of mine, and also an old client of mine. So, I did my editing, and told the new client that another round of editing is needed before the paper is submitted. WHO said ok. I waited, and did others things while waiting. FIVE more new clients came (yeah, I guess I must be good at editing), which kept me busy, not to mention that I have my own paper to write (which gives me many real headaches). This morning, I received an invitation from JGR to review a paper. I thought the topic was familiar but the authors we re NOT; in particular, I knew the second author and I did not edit his paper on this topic. So, I clicked "accept" to review, and thinking that I could get this review done today, because voting in Kahala should not take much time. As soon as I saw the first author's affiliation, I knew I was IN BIG TROUBLE. I went back to my log and saw I did edit this paper a month ago! Shxt, I was pissed! I had to search for the editor's real email, and explained to him why I messed up... This Blog will not be open for long, since I don't think WHO will read it soon but might if I kept it open. It bothers me a great deal why WHO did what WHO did, such as changing the second author's name, and naming me as one of the potential reviewers. Does WHO know what honesty is, or what conflict of interest means??? T he tough question for me is whether or not I should blacklist WHO ...
One earth, one life ------Human common belief in future Xiao Ming Wang Hubei University of Traditional Chinese Medicine China E-mail: shermanwang@yahoo.com.cn , foxglove@163.com Abstract: The author proposed a new perspective to contemplate the nature of life and pursue the philosophy of life and healthy. He first g a ve the definition of what is one life sufficiently and necessarily. Any one thing or one body which has following five characteristics is one life: from small to big (growth); from one to two or one generation to next generation (reproduction); self-regulation; can be killed; age to death; he concluded the basic tendency of life development on the earth, discuss ed the relation of human life and the life surround human. The human life faced the challenge in era of globalization . Propose d human should have a community common belief in future: one earth is one life. All people of whatever country or ethnic should love one earth life and preserve the life of earth . It is determine the destiny of the humankind Keywords : the definition of one life; human common belief; the development of life; the philosophy of life and healthy; the challenge of globalization 1. I ntroduction As the developing of internet technique and globalization of world economy, the knowledge of science and technology spread all over the world. Human society has tremendous change. The environment of the earth also changes sharply. All life on the earth inevitably to adapt to this new tendency. What life may survival in future on earth? Human behavior has made a great impact on the system of all bio-organisms on the earth . T he integration of t he world economy gradually impacts all human society to become one life organism. But this change may also cause many great challenges for every people survive in the world life system. It may cause financial crisis, political conflict, military competition , nuclear war and other social problem , or disaster , or tragedy. One human life need all man has common belief. Only human common belief can make human have common criterion of human behavior that can judge about what is correct and what is wrong. H uman also need to regulate their behavior to accommodate to the change of environment . Without common belief, human life will has endless social and state conflicts. 2. The concept of one life and The development of life on earth Aristotle said that all man by nature want to know. Man wants to know every being as being surrounded him and every thing about himself. What is the most general and fundamental inquiry that man wants to know? What is life? How is the life on the earth developing? What is the relation of the human life and the lives surrounded us? Because the abundan ce of phenomena of life, people are perplexed by the concept of what is life. The current understanding is descriptive. Life is considered a characteristic of organisms that exhibit all or most of the following: Homeostasis :. Organization :. Metabolism :. Growth :. Adaptation : Response to stimuli :. Reproduction : Although it is still a challenge for scientists and philosophers to define life in unequivocal terms, we can precisely, sufficiently and necessarily give a definition of what is one life. Any one thing or one body has following five characteristics that can be said one life: growth (from small to big); reproduction (from one to two or from one generation to second generation); self-regulation; can been killed; age to death. Each one life has four period of life expectation: birth; growth; reproduction; death. From this philosophical perspective, we can better understand the life of human body, human society and the lives surrounded human. We can better survive on the earth, preventing our lives from diseases, wars and social tragedy. We can better treat the relation of the human life and the lives surrounded us and adjust our life to coordinative with the environment, protecting the environment and prolonging our lifespan. It is so common and important question that everyone should know what is one life. One life is a process, not a pure substance. Any definition must be sufficiently broad to encompass all life with which we are familiar, and must be necessarily general to include life that may be fundamentally different from life on Earth. The holistic idea of the Earth as an integrated whole, a living being, has a long tradition, but the first scientific discussion was by the Scottish scientist James Hutton . James lovelock first proposes the Gaia hypothesis that all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system , maintaining the conditions for life on the planet. According to the perspective that we suggested, you know each cell of you body has one life. All cells of yours compose one body, which is your one life. Your central nervous system regulates all lives of your cells, adjusted whole body to adapt the change of surroundings. Your body is one complicate cell social organism. Your family is one life. Your company is one life. The city you lived in is one life. Your native is one life. Your country is one life. The whole biosphere of the earth is one life. It regulates all lives on the earth, self- sustaining itself from one generation to second generation and keeping all material on earth surface to recycle, especially carbon , nitrogen and water recycling . It transport solar energy to biological energy and transmits energy on the surface of the earth. From the history of life developing on earth as we known, we can conclude: The earth biosphere consist of many different life species, life types, and life levels. Same life species live on same energy and materials in same way. Different life species live on different material or different energy or in different space. A species of life can differentiate to many different types of life. Different life type live on same material in same space has different function. A level of life may be composed of many life types and/or life species,. More life levels sustain the life more stable on the earth. Which kind of life can survive a long lifespan? The development of life has three tendencies: Life Species evolution --- survival of the fittest , which Charles Darwin first proposed the T heory of Evolution; Life Type specialization ---- survival of the most efficient, Life Level multiplication --- survival of the more stable homeostasis system. Chemical material transform, energy transmit, information transport t more efficient in multi level life system. 3. T he relationship of human life and the life around human According to the perspective we suggested above, human life is a part of one earth life. One earth life has self-regulated all species of life on the biosphere; one life is an open self-regulation system. No life can survive in an isolated close space consistently. This has been demonstrated by the Biosphere 2 in Oracle, Arizona (USA) . As the climate change, all life species should evolve to adapt the change. All life level control wh at species may sustain to survive. Human life belongs to his ecological life . H uman has no ability to control his ecological life, but human life or human behavior may force the ecological life change or evolution. We all often see some specie life suddenly burst out in some ecological system, all of this species regulated by his ecological life when the species life unbalance. If the life specie sharply unbalance, that may cause many species life extinct. Some new evolve specie life bring out. Or wholly ecological life dies . The more specie life in one ecological life, the more stable ecological system, and the stronger the one ecological life is. Otherwise on contrast the ecological life is weak er . As the human life become too strong, it may cause may other species life extinct. This behavior wills weak the ecological life. All material should recycle on biosphere of earth. In o ne health life , chemical materials transform continua lly , energy transport in balance. The e arth rotates day and night. It causes s olar light energy transport on earth unbalance on the surface. This unbalance cause s the transport ation of energy and material of the earth unsmooth . Thus lead the climate unstable a nd atmosphere recycle unstable. At the life beginning on the earth, there was only one kind of original primitive specie of life. As this life was from one to two, and more, the shortage of space and energy and material happened . Some move d to other place or space to survive, some evolve d new specie life to live on new material and energy, some organize d more level to more efficiently use material and energy . A ll of this improves the climate stable and environment stable. Life grows gloriously on earth. 4. T he challenge of human life in an Era of Globalization As the developing of human society and economical globalization, the human gradually been integrated to one human life. This also causes great challenge for the survival of human life. Different country and ethnic have different history, culture and value. They are on different developing level. Different h uman r ights conception and c ultural d iversity may cause many conflicts. The growing economy disparity in wealth and access to resources, coincide with an alarming increase in violence, poverty and unemployment, and the erosion of environmental stability. At the same time, previously isolated peoples are being brought together voluntarily and involuntarily by the increasing integration of markets, the emergence of new regional political alliances, and remarkable advances in telecommunications and transportation that have push all people to become a life organism which need more complicate self-regulate mechanism. . This situation sharpens a long-standing dilemma: Li fe existed on the earth face many challenges and risk . M any factors can kill the life. Some unbalances may cause human social tragedy: How human can keep human life healthy developing and prevent from economic and social crisis? Does our generation can find enough wisdom to solve the problem? W henever and what ever kind change take place between groups of human, nobody can change that all human life belong a part of an earth life, one earth life certainly regulate all human life in itself own natural mechanism. 5. Human common belief Although Human life has not integrated to become one life completely and perfectly nowadays, human life certainly belongs to one earth life . I n the history of human, human individual or organisms or country have no ability to destroy the one earth life . A s the science and technology develop in whole world in future and economy growth and environment destruction, the behavior of some country or some individual may have some ability to do some thing destroy the one earth life that the earth life can not self-regulate to repair the damage of human behavior, that will be made the one earth life can not from one generation to next generation. The life on the earth is end. As the human life gradually to become one single life, wholly people need common belief. Only have common belief that human can build up a series of self-regulation method to sustain one human life with one earth life harmony . P eople from different culture and different history can set up same criterion to have international law or rule to regulate human behavior, to force human life adapt to one earth life change .and prolong human life expectation . The development of human economy system and politics system is more health , social stability economic prosperous keep the life system harmony growth and reproduction . Only all human have common belief can rescued human life from nuclear war and massacre . without common belief , the growth of country must lead the contest of the material source and space. Different political philosophy can not coexist together finally the military war happens. Human society may conflict endless and individual may easily has mental disorder People believe G od he unwilling to do anything against Jesus, people believe Buddhism he unwilling to do anything against Buddha Mani. People believe Muslim he unwilling to do anything against Mohammed. People believe one earth is one life, he unwilling to do anything harmful the life system of the earth. Although some religious belief that earth is alive, that one earth is one life is scientific belief . I t is truth of life. WE BELIEVE IN THE SEARCH FOR TRUTH, THE QUEST FOR BEAUTY, AND THE STRUGGLE FOR EXCELLENCE; IS GOOD LIVING; A. Vaughan Abercrombie References Iztok Prezelj , HUMSEC Challenges in Conceptualizing and Providing Human Security http:// www. humsec .eu/cms/index.php?id=356 Diana Ayton-Shenker, The Challenge of Human Rights and Cultural Diversity ( Published by the United Nations Department of Public Information ) DPI/1627/HR--March 1995 http://www.un.org/rights/dpi1627e.htm Joseph Morales , The Definition of Life Psychozoan: A Journal of Culture Copyright 1998 http://www.baharna.com/philos/life.htm Daniel E Koshland Jr , The seven pillars of life . Science . Washington: Mar 22, 2002 . Vol. 295, Iss. 5563; pg. 2215, 2 pgs h ttp:// www.sciencemag.org/content/295/5563/2215.full.pdf Definition of life Encyclopedia Britannica 2007 Ultimate Reference Suite Wikipedia, Life http://en.wikipedia.org/wiki/Definition_of_life Wikipedia, Philosophy of biology http://en.wikipedia.org/wiki/Philosophy_of_biology A. V. Abercrombie, COMMON BELIEFS TO LIVE BY , http:// www.naccc.org/CMSUploads/474_ Common _ Beliefs .pdf
Propensity score matching 是时下经济学评价政策效应的流行方法。或许用生物里的对照实验来解释比较好。假设我们需要了解一种新药的疗效，我们不能同时观察到同一个体接受治疗和没有治疗的结果。所以它的基本思想是在找到未参与者作为 对照组 ，他们接受治疗前特征与实验组应该尽可能的相似，所谓“其他条件一致”。这个特征（common support）的选择，以及相似的标准（matching algorithm）则正是propensity score matching的核心了。这个方法从生物学研究发展到经济学研究政策效应或许都源于个体对自己的思考。 你的面前有两条路，你选择了一条，如何知道选择了另一条与现在的你有多大的差别呢？这个世界再找不到一个同样的你来完成这样的一个实验，所以这对生物学家来说一定是一个难题，因为这无法在实验室完成，对经济学家而言，一定是成本大于收益的。但他们可以找到另一个特质与你及其相似的你，可惜总不能让你的父母生下双胞胎的另一个你来完成这样的一个实验， 但无论如何这都是兴师动众的一样活。 又或者当人们都好奇到如此，形成了一个市场，让物理学家们来开发这样的一个产品，在另一个星球有另一个你（正物质，反物质？），在交叉口你选择了另一条路，再现在地球上生活的你。让你得以瞥见另一个自己，是欢笑是悲伤，又或者是一样的碌碌无为。这或许应该交给像Robert Frost 这样的诗人。 The Road Not Taken Two roads diverged in a yellow wood, And sorry I could not travel both And be one traveler, long I stood And looked down one as far as I could To where it bent in the undergrowth; Then took the other, as just as fair, And having perhaps the better claim Because it was grassy and wanted wear, Though as for that the passing there Had worn them really about the same, And both that morning equally lay In leaves no step had trodden black. Oh, I marked the first for another day! Yet knowing how way leads on to way I doubted if I should ever come back. I shall be telling this with a sigh Somewhere ages and ages hence: Two roads diverged in a wood, and I, I took the one less traveled by, And that has made all the difference.
1996 Effect of steam and carbon dioxide activation in the micropore size distribution of activated carbon The three series of activated carbons were prepared from a common char, prepared by the carbonization of olive stones (nitrogen flow of 80 ml min -1 ; 850 ℃ ; heating rate, 5 ℃ min -1 ; residence time 2 hours). Activated carbons prepared by carbon dioxide activation exhibit a larger micropore volume and a narrower micropore size distribution than those prepared by steam activation. 2001 Mesoporous high-surface-area activated carbon The shells or seeds were dried at 110 o C, crushed and sieved to a uniform size of 1.0–2.0 mm. Subsequently, ZnCl 2 in the form of a powder and about 10 ml of water were added to the raw material to provide ZnCl 2 -to-shell ratios varying from 0.25 to 3 by weight. The mixtures were dehydrated overnight at 110 o C and pyrolysed under a flow of nitrogen in a quartz tube held in a horizontal furnace (Carbolite). The temperature was ramped at 10 o C/min up to 800 o C. Nitrogen was replaced by CO 2 when the temperature reached 800 o C and the carbon soaked at these conditions for 2–3 h. The activated products were then cooled, washed successively with deionised water, hydrochloric acid (0.1 mol/l) and hot deionised water to remove the zinc and chloride compounds. After overnight drying in air at 110 o C, N 2 adsorption–desorption isotherms of the carbons were measured using a gas sorption analyser (Nova-1000, Quantachrome) to determine surface area and pore volume. At low ZnCl 2 -to-shell ratios, micropore formation is the dominating mechanism; pore widening becomes important as the ratio increases. Pore widening takes place at the expense of micropore formation for high ZnCl 2 -to-shell ratios, thereby reducing the micropore content. 2003 Production of granular activated carbon from fruit stones and nutshells and evaluation of their physical, chemical and adsorption properties Almond, walnut, hazelnut shells and apricot stones were used as starting materials. These raw materials were broken with a Waring commercial blender and sieved to a particle size of 1–1.25 mm in diameter. Granulated raw materials were dried at 110 o C for 24 h. Dried raw materials were mixed with a solution of ZnCl2 (30 wt.%). The mixture was dehydrated at 103 o C for 6–10–18–24 h and subsequently activated at 750–800–850 o C for 2 h in the presence of N 2 (40 ml min -1 flow rate). The activated samples were washed initially with 1.2 M hydrochloric acid solution. Further washing was done with hot distilled water. Products were dried at 110 o C for 24 h in a thermostatically controlled oven.
Several common issues in English papers written by Chinese Authors 1. 不按投稿要求准备稿件 Manuscripts are not prepared according to the requirements of the object journals. This phenomenon is very common, especially in literature citation and reference indexing. Some manuscripts submitted to the JMS still follow the citation-order system while JMS requires author-year system. Besides reference, JMS have strict requirements on figure format and size, even on the word fonts and the word size in the figures. In addition, JMS requires the authors’ family names be capitalized, the corresponding author’s email address be listed. The manuscripts which can’t follow the JMS Guidelines will be returned to the authors for revision and then resubmit. This will greatly prolong the manuscript processing period. 2. 摘要很短或者摘要中大部分介绍研究目的 The manuscript has only a brief abstract or the research objective occupies the large part of the abstract. In an original paper, an abstract should include the research objective (should be introduced concisely), the study methods or technology (such as the study sites, study materials, major test equipment or facilities, main experimental process, statistical or analytical methods), and the important study results and conclusions. Some papers use a great deal of words to describe the research purpose (objectives) but only one or two sentences to describe the research methods and results. It looks top-heavy. 3. 只把读者定位在中国人群 Some Chinese authors seem to take the papers’ readers to be Chinese only. To a Chinese, some abbreviations have very clear meaning, but it's not the case to a foreignreader or reviewer . Usually they have the following characteristics: (1) Writing some events in abbreviations and don’t give any further description, such as “the 5.12 Earthquake ”; (2) Frequently using “at home and abroad” in the paper while it refers to “China and other countries”. In fact it doesn’t need to add this phrase. As an international English journal, JMS has readers and authors around the world. So every author with his manuscript submitted to JMS should take his readers globally, and his literature review also should NOT be limited in his own countries’ literature but all the important and directly relevant literature around the world. In the discussion part, it should bethe same. Here I have several examples which repeatedly mention “at home and abroad” in the literature review. Example one : “The quantitative test and analysis about the viscoelastic behaviors of different viscous debris flows from triggering, thixotropy and shearing movement were not developed both at home and abroad for the restrictions of rheological equipments. Example two : The rheological dynamic oscillatory tests were made to study the debris flow slurry from Jiangjiagou Ravine with the further rheological research at home and abroad . Example three : The quantitative test and analysis about the viscoelastic behaviors of different viscous debris flows from triggering, thixotropy and shearing movement were not developed both at home and abroad for the restrictions of rheological equipments. (3) Use a chain of Pinyin for the names of the sites, which greatly confuse a reader who can’t understand Pinyin. In a manuscript about the secondary disaster caused by the May 12 Wenchuan Earthquake, the authors mentioned many sites, including administrative regions, rivers, mountains, valleys, and so on, but they are all in Pinyin. Example: The 5.12 Earthquake along the Longmenshan has caused great economic and life loss, and a chain of secondary disasters in Wenchuan, Qingchuan, and Beichuan. The 8.13 Big Debris Flow in Qingping town occurred with extremely high hazard grade.
最近的两项研究表明，目前常用的杀虫剂，即使是低剂量的使用，也会造成蜜蜂存活和繁殖能力下降。 1. Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production Penelope R. Whitehorn , Stephanie O’Connor , Felix L. Wackers , and Dave Goulson Published online 29 March 2012 2. A Common Pesticide Decreases Foraging Success and Survival in Honey Bees Mickal Henry , Maxime Beguin , Fabrice Requier , Orianne Rollin , Jean-Franois Odoux , Pierrick Aupinel , Jean Aptel , Sylvie Tchamitchian , and Axel Decourtye Published online 29 March 2012 Bees harmed by low levels of common pesticides CBC News Posted: Mar 29, 2012 2:03 PM ET Last Updated: Mar 29, 2012 5:10 PM ET Buff-tailed bumblebees produced 85 per cent fewer queens when exposed to low doses of pesticides. (P. Whitehorn/Science/AAAS) Even low doses of popular pesticides can reduce bees' survival and reproduction, two new studies show. The findings bolster evidence that such chemicals may be partly responsible for recent declines in populations of honeybees and bumblebees in North America and Europe, which have caused alarm due to the insects' importance as crop pollinators. The researchers suggest the widespread use of the pesticides needs to be re-evaluated in light of the findings. The two studies, published Wednesday in the journal Science, looked at the effects of pesticides called neonicotinoids on bumblebees and honeybees, respectively. Neonicotinoids, first introduced in the 1990s, are used to kill aphids and other sap-sucking insects. According to a news release from Science, they are now some of the most widely used crop pesticides in the world. Bayer Crop Sciences, which is the leading producer of this type of pesticide, told The Associated Press that it is used on 90 per cent of the corn grown in the U.S. and is safe. In the first study, led by Penelope Whitehorn at the University of Stirling in Britain, colonies of buff-tailed bumblebees were fed doses of a neonicotinoid pesticide called imidacloprid in doses similar to those that they would be exposed to in the wild when foraging among crops sprayed with the pesticides. The bees were then allowed to forage for six weeks. The researchers found that bumblebees exposed to the pesticide had nests that were an average of eight to 12 per cent smaller than colonies that weren't exposed. They also produced 85 per cent fewer queen bees. That could have a huge effect on bumblebee populations, because all bumblebees except the queens die when winter sets in. Bumblebee populations rely on the queens to survive the winter and found new colonies in the spring. In the second study, led by Mickal Henry of the French National Institute for Agricultural Research in Avignon, France, honeybees were fed small doses of a different neonicotinoid pesticide called thiamethoxam. They were then tracked with small microchips called RFID tags. The researchers found that 10 to 31 per cent of bees exposed to the pesticide did not return to their colony after being released to forage for the day. That was up to double the estimated normal mortality rate for a honeybee on a given day, about 15 per cent. The pesticide appears to interfere with the bees' ability to navigate and find their way back to the colony, an effect that has been shown in previous studies. Henry noted that currently, in order to get a pesticide approved, the manufacturer must show that the product does not directly kill bees when applied to a field. "But they basically ignore the consequences of doses that do not kill them but may cause behavioral difficulties," he said in a statement. David Goulson, who co-authored the British study with Whitehorn, said the use of neonicotinoid pesticides "clearly poses a threat" to the health of bees and "urgently needs to be re-evaluated." However, Bayer eco-toxicologist David Fischer said the honeybee study used doses of pesticides far higher than those used on crops bees normally pollinate. The study had described the dose as "field-realistic." Many bee species have been declining in North America and Europe, and some have even gone extinct or are believed to be close to extinction. Meanwhile, honeybees, which are used to pollinate important crops such as raspberries, cherries, and almonds have been suffering since around 2006 from a phenomenon called Colony Collapse Disorder, in which worker bees disappear suddenly. Pesticides are only one of the possible causes. Recent studies have suggested that fungi and viruses or parasites may be to blame. http://www.cbc.ca/news/technology/story/2012/03/29/science-bees-decline-pesticides.html
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Lame parameters of common rocks in the Earths crust and upper mantle Shaocheng Ji , Shengsi Sun, Qian Wang , and Denis Marcotte Dpartement des Gnies Civil, Gologique et des Mines, cole Polytechnique de Montral, Montral, Qubec, Canada JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, B06314, doi:10.1029/2009JB007134, 2010. Received 13 November 2009; revised 15 January 2010; accepted 28 January 2010; published 24 June 2010. Lame parameter () and shear modulus () are the most important, intrinsic , elastic properties of rocks. , which relates stresses and strains in perpendicular directions, is closely related to the incompressibility and contains a high proportion of information about the resistance to a change in volume caused by a change in pressure . Recent studies have emphasized the role played by in the discrimination of gas sands from carbonates and shale in sedimentary basins. Here we analyzed the equivalent isotropic elastic data of 475 natural rocks in order to characterize values for common types of crystalline rocks in the Earths crust and upper mantle and their variations with pressure (P), temperature (T) and mineralogical composition. When no partial melting, metamorphic reaction, dehydration or phase transformation occurs, of a crystalline rock as a function of P and T can be described by , where a is the projected value at zero pressure if micro crack s were fully closed ; b is the pressure derivative in the linear elastic regime ; c is the initial drop caused by the presence of microcracks at zero pressure; k is a decay constant of the drop in the nonlinear poro-elastic regime; and is the temperature derivative of . increases nonlinearly and linearly with increasing pressure at low (~300 MPa) and high (~300 MPa) pressures, respectively. In the regime of high pressures, decreases quasi-linearly with increasing temperature with values in the range of 1-10 10 -3 GPa/C. Approaching the - quartz transition temperature, quartzite displays negative values. In the - (density) and - plots, the main categories of lithology can be clearly distinguished. The ultramafic rocks display systematic decreases in both and with increasing the degree of serpentinization. Eclogites, mafic rocks (gabbro, diabase, mafic granulite, and mafic gneiss) and felsic rocks (granite, diorite, felsic gneiss, intermediate gneiss and metasediments) are characterized by high, moderate and low and values, respectively. For pyroxene and olivine, both and increase but decreases with increasing the Fe/Mg ratios. In the plagioclase series, both and increases with increasing the anorthite content. Increases in the contents of garnets, sillimanite, rutile, zircon, ilmenite and spinel result systematically in an increase in rocks and values. The present results provide improved constraints on the discrim in ation of composition for crustal and upper mantle rocks in terms of and .
标签: common
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