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71.
A well‐written application for funding in support of basic biological or biomedical research or individual training fellowship requires that the author perform several functions well. They must (i) identify an important topic, (ii) provide a brief but persuasive introduction to highlight its significance, (iii) identify one or two key questions that if answered would impact the field, (iv) present a series of logical experiments and convince the reader that the approaches are feasible, doable within a certain period of time and have the potential to answer the questions posed, and (v) include citations that demonstrate both scholarship and an appropriate command of the relevant literature and techniques involved in the proposed research study. In addition, preparation of any compelling application requires formal scientific writing and editing skills that are invaluable in any career. These are also all key components in a doctoral dissertation and encompass many of the skills that we expect graduate students to master. Almost 20 years ago, we began a grant writing course as a mechanism to train students in these specific skills. Here, we describe the use of this course in training of our graduate students as well as our experiences and lessons learned.  相似文献   
72.
The carbon footprint of flying overseas to conferences, meetings, and workshops to share and build knowledge has been increasingly questioned over the last two decades, especially in environmental and climate sciences, due to the related colossal carbon emissions. Here, we infer the value of scientific meetings through the number of publications produced either directly or indirectly after attending a scientific conference, symposium, or workshop (i.e., the conference‐related production) and the number of publications produced per meeting (i.e., the conference‐related productivity) as proxies for the academic value of these meetings, and relate them to both the number of meetings attended and the related carbon emissions. We show that conference‐related production and productivity, respectively, increase and decay with the number of meetings attended, and noticeably that the less productive people exhibit the largest carbon footprint. Taken together, our results imply that a twofold decrease in the carbon footprint FCO2 of a given scientist would result in a twofold increase in productivity through a fivefold decrease in the number of meeting attended. In light of these figures, we call for both the implementation of objective and quantitative criteria related to the optimum number of conferences to attend in an effort to maximize scientific productivity while minimizing the related carbon footprint, and the development of a rationale to minimize the carbon emission related to scientific activities.  相似文献   
73.
Aims To clarify whether variation in leaf traits with climate differs with scale, i.e. across species and within a species, and to detect whether plant functional group affects species-specific response.Methods Leaf dry matter content (LDMC), specific leaf area (SLA), mass- and area-based leaf N (N mass, N area) and leaf P concentrations (P mass, P area) and leaf chlorophyll concentration (SPAD) were measured for 92 woody plant species in two botanical gardens in China. The two gardens share plant species in common but differ in climate. Leaf trait variation between the two gardens was examined via mean comparison at three scales: all species together, species grouped into plant functional groups and within a species. A meta-analysis was performed to summarize the species-specific responses.Important findings At the scale of all species together, LDMC, SLA, P mass and N mass were significantly lower in the dry-cold habitat than in the wet-warm one, whereas N area and SPAD showed an inverse pattern, indicating a significant environmental effect. The meta-analysis showed that the above-mentioned patterns persisted for SLA, N area and SPAD but not for the other variables at the species-specific scale, indicating that intraspecific variation affects the overall pattern of LDMC, P mass and N mass and P area. In terms of species-specific response, positive, negative or nonsignificant patterns were observed among the 92 species. Contrary to our prediction, species-specific responses within a functional group were not statistically more similar than those among functional groups. Our results indicated that leaf trait variation captured climatic difference yet species-specific responses were quite diverse irrespective of plant functional group, providing new insights for interpreting trait variability with climate.  相似文献   
74.
The objectives of this research are: (1) to assess selected formulation-relevant physical properties of several commercial Feverfew extracts, including flowability, hygroscopicity, compressibility and compactibility (2) to develop and validate a suitable extraction method and HPLC assay, and (3) to determine the parthenolide content of several commercial Feverfew extracts. Carr’s index, minimum orifice diameter and particle-particle interaction were used to evaluate powder flowability. Hygroscopicity was evaluated by determining the equilibrium moisture content (EMC) after storage at various % relative humidities. Heckle analysis and compression pressure-radial tensile strength relationship were used to represent compression and compaction properties of feverfew extracts. An adapted analytical method was developed based on literature methods and then validated for the determination of parthenolide in feverfew. The commercial extracts tested exhibited poor to very poor flowability. The comparatively low mean yield pressure suggested that feverfew extracts deformed mainly plastically. Hygroscopicity and compactibility varied greatly with source. No commercial feverfew extracts tested contained the label claimed parthenolide. Even different batches from the same manufacturer showed significantly different parthenolide content. Therefore, extract manufactures should commit to proper quality control procedures that ensure accurate label claims, and supplement manufacturers should take into account possible differences in physico-chemical properties when using extracts from multiple suppliers.  相似文献   
75.
刘彬  吴福忠  张健  杨万勤 《生态学报》2008,28(12):5892-5898
作为典型的生态过渡区,岷江干旱河谷-山地森林交错带不仅是藏羌居民生活的重要区域,而且在抑制干旱河谷上延和延伸亚高山森林生态系统的功能等方面具有十分重要的作用。但这种脆弱生态系统极易受到人类活动干扰和自然灾害的损害,使其成为“5.12”汶川大地震中受损程度较高、灾后生态恢复与重建的重点区域之一。基于岷江干旱河谷-山地森林交错带受汶川大地震破坏的特点以及该区的生态重要性和本身的脆弱性,损毁生态系统的快速评估与生态重建规划、生产与生态双赢共建关键技术、震后残存植被保育、水源涵养地植被保护与恢复、震毁植被恢复与重建、耕地生产恢复与重建、边坡综合治理、低效薪炭林改良以及居民聚居点风景林营造等被认为是震后生态恢复的关键科学技术问题。震毁生态系统的生态恢复过程监测与评估、干旱河谷-山地森林交错带生态系统的脆弱性机制及生态学过程、震后生态系统对变化环境的响应与适应机制等可能是未来的重点研究领域。  相似文献   
76.
雷公藤的杀虫作用研究与应用   总被引:3,自引:0,他引:3  
卫矛科植物雷公藤(Tripterygium wilfordli Hook)是我国著名的杀虫植物。文章对雷公藤的杀虫活性、主要有效成分、作用机理及田间药效4个方面的研究与应用进行综述。雷公藤对多种昆虫有毒杀、拒食、麻醉、生长发育抑制和种群抑制作用;雷公藤定碱、雷公藤次碱、雷公藤春碱、雷公藤吉碱、雷公藤嗪碱、雷公藤新碱和雷公藤甲素、雷公藤内酯酮是其主要杀虫活性成分;雷公藤生物碱作用于昆虫的神经系统和中肠肠壁细胞,Na+,K+-ATP酶可能是雷公藤甲素的靶标之一;雷公藤还具有较好的田间防效。最后,对雷公藤作为杀虫植物资源的开发利用前景和今后的研究方向作了展望。  相似文献   
77.
Ansquer P  Duru M  Theau JP  Cruz P 《Annals of botany》2009,103(1):117-126
Background and Aims: Fodder provision in species-rich grasslands, i.e. herbage growth,proportion of leaf, and leaf and stem digestibility, is difficultto predict for short periods of time, such as between two defoliationsor less. The value of two methods based on plant traits forevaluating these agronomic properties was examined. Methods: One method is based on plant trait measurements on the plantcommunity (leaf dry matter content, plant height, floweringdate); the other is on vegetation composition expressed as plantfunctional types (acquisitive versus conservative PFTs) establishedby measuring leaf dry matter content on pure grass stands. Theexperiment consisted of 18 fields with three different defoliationregimes (combinations of cutting and grazing) and two levelsof fertilization. To establish a growth curve over the firstgrowth cycle, herbage was sampled about 10 times in spring. Key Results: Coefficients of correlation between agronomic properties ofthe vegetation and its functional composition were higher whenthe latter was assessed through PFT and an indicator of theplant nutrient status (Ni) instead of measured plant traits.The date at which the ceiling yield occurred for the standingherbage mass or only the leaf component, which varied by upto 500 degree-days between treatments, and the leaf proportion,depended entirely on the PFT, and largely so for the leaf digestibility.The standing herbage mass at the time of ceiling yield dependedonly on Ni, or mainly so in the case of the daily herbage growthrate. Similar plant digestibility between plant communitieswas found at flowering time, although there were big differencesin PFT composition. The shape of the growth curve was flatterwhen there was great functional diversity in the plant community. Conclusions: The PFT composition and the Ni were more reliable than the plantfunctional traits measured in the field for evaluating herbagegrowth pattern and digestibility in spring.  相似文献   
78.
As a Cambridge University undergraduate Charles Darwin was fascinated and convinced by the argument for intelligent design, as set forth in William Paley’s 1802 classic, Natural Theology. Subsequently, during his five-year voyage on HMS Beagle (1831–1836), Darwin interpreted his biological findings through a creationist lens, including the thought-provoking evidence he encountered during his historic visit to the Galápagos Islands in September and October 1835. After his return to England in 1836 and his subsequent conversion to the idea of organic evolution in March 1837, Darwin searched for a theory that would explain both the fact of evolution and the widespread appearance of intelligent design. His insight into the process of natural selection, which occurred in September 1838, provided this alternative explanation. Darwin’s Origin of Species (1859) exemplifies his skillful deployment of the hypothetico-deductive method in testing and refuting the arguments for intelligent design that he had once so ardently admired.  相似文献   
79.
研究生细胞分子生物学教学探索   总被引:1,自引:0,他引:1  
为了培养具有科研思雏、德才兼备的研究生,在细胞分子生物学的教学中,从与人类生活及疾病相关的问题入手,以近年诺贝尔生理学或医学奖获奖相关工作为主线,要求学生阅读指定文献并自己查阅相关文献,采用启发式或讨论式等多种方式开展教学,让学生在学习过程中经历了文献查阅、综述撰写、会议报告的制作等过程,使学生掌握了基础理论,增强了发现问题的意识,培养了解决问题的能力,提高了学术交流的技能。从而使学生的道德修养和综合素质有了显著提高,为今后从事科学研究工作奠定了良好的基础。  相似文献   
80.
Dispersal of biota by humans is a hallmark of civilization, but the results are often unforeseen and sometimes costly. Like kudzu vine in the American South, some examples become the stuff of regional folklore. In recent decades, “invasion biology,” conservation-motivated scientists and their allies have focused largely on the most negative outcomes and often promoted the perception that introduced species are monsters. However, cases of monstering by scientists preceded the rise of popular environmentalism. The story of tamarisk (Tamarix spp.), flowering trees and shrubs imported to New England sometime before 1818, provides an example of scientific “monstering” and shows how slaying the monster, rather than allaying its impacts, became a goal in itself. Tamarisks’ drought and salt tolerance suggested usefulness for both coastal and inland erosion control, and politicians as well as academic and agency scientists promoted planting them in the southern Great Plains and Southwest. But when erosion control efforts in Arizona, New Mexico and Texas became entangled with water shortages, economic development during the Depression and copper mining for national defense during World War Two, federal hydrologists moved quickly to recast tamarisks as water-wasting foreign monsters. Demonstrating significant water salvage was difficult and became subsidiary to focusing on ways to eradicate the plants, and a federal interagency effort devoted specifically to the latter purpose was organized and continued until it, in turn, conflicted with regional environmental concerns in the late 1960s.  相似文献   
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