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21.
<正>本报告强调:当有关科研人员及其机构的数据被压缩为简单的指标和排名时,有些信息将会遗失。本报告阐述了四类常见分析,如若误用将掩盖真实的科研表现;我们提出了四种可视化选项,用于解读每个度量指标下蕴含的更丰富的信息,以支持开展全面的、负责任的科研管理。我们身边依然存在着声称可通过简单分析来评估论文、科研人员和机构表现的现象。尽管资深分析专家提出反对意见,诸多研究人员对此深表忧虑,但是大学管 相似文献
22.
The small deciduous tree Celtis reticulata (neatleaf hackberry) reaches its northern limit in Idaho, where, contrary to most of its western range, it often occurs as an overstory dominantly. Two hundred fifty stands of this tree were sampled throughout Idaho. Celtis is slow-growing, averaging 4 m tall at 50 yr, and long-lived (to 300-400yr). It occurs in a variety of habitats, from riparian to rocky uplands. Trees grow best where topographically sheltered, such as in draws and narrow canyons, and were soils are loamy. Although plants grow more slowly as surface rock cover increases, stands are often associated with rock, with a mean surface cover of 39% rock. Differences in growth rates were unrelated to parent material and aspect. Most stands are reproducing, in spite of habitat degradation caused by overgrazing, alien plant invasion, and increasing fire frequencies. Stands are typically represented by one dominant cohort; however, young, even-aged stands are rare and are generally found along waterways on stream terraces or at the high-water line. Although slow growing, C. reticulata shows promise for land mangers interested in site enhancement. This native species is long-lived, produces fruit used by wildlife, and provides structural diversity in a semiarid landscape (with a maximum height o 12 m) in areas that are becoming increasingly dominated by exotic plant species. 相似文献
23.
Marie Novak 《Cellular and molecular life sciences : CMLS》1978,34(9):1149-1149
Summary Mice kept at low (5±1 °C) and high (35±1 °C) temperature harboured significantly lessTaenia crassiceps cysticerci than controls kept at 21±1 °C. This effect was more pronounced in heat-stressed than in cold-stressed animals and more in males than in females. 相似文献
24.
Systematic generation of high-resolution deletion coverage of the Drosophila melanogaster genome 总被引:1,自引:0,他引:1
Parks AL Cook KR Belvin M Dompe NA Fawcett R Huppert K Tan LR Winter CG Bogart KP Deal JE Deal-Herr ME Grant D Marcinko M Miyazaki WY Robertson S Shaw KJ Tabios M Vysotskaia V Zhao L Andrade RS Edgar KA Howie E Killpack K Milash B Norton A Thao D Whittaker K Winner MA Friedman L Margolis J Singer MA Kopczynski C Curtis D Kaufman TC Plowman GD Duyk G Francis-Lang HL 《Nature genetics》2004,36(3):288-292
In fruit fly research, chromosomal deletions are indispensable tools for mapping mutations, characterizing alleles and identifying interacting loci. Most widely used deletions were generated by irradiation or chemical mutagenesis. These methods are labor-intensive, generate random breakpoints and result in unwanted secondary mutations that can confound phenotypic analyses. Most of the existing deletions are large, have molecularly undefined endpoints and are maintained in genetically complex stocks. Furthermore, the existence of haplolethal or haplosterile loci makes the recovery of deletions of certain regions exceedingly difficult by traditional methods, resulting in gaps in coverage. Here we describe two methods that address these problems by providing for the systematic isolation of targeted deletions in the D. melanogaster genome. The first strategy used a P element-based technique to generate deletions that closely flank haploinsufficient genes and minimize undeleted regions. This deletion set has increased overall genomic coverage by 5-7%. The second strategy used FLP recombinase and the large array of FRT-bearing insertions described in the accompanying paper to generate 519 isogenic deletions with molecularly defined endpoints. This second deletion collection provides 56% genome coverage so far. The latter methodology enables the generation of small custom deletions with predictable endpoints throughout the genome and should make their isolation a simple and routine task. 相似文献
25.
Boyd PW Law CS Wong CS Nojiri Y Tsuda A Levasseur M Takeda S Rivkin R Harrison PJ Strzepek R Gower J McKay M Abraham E Arychuk M Barwell-Clarke J Crawford W Crawford D Hale M Harada K Johnson K Kiyosawa H Kudo I Marchetti A Miller W Needoba J Nishioka J Ogawa H Page J Robert M Saito H Sastri A Sherry N Soutar T Sutherland N Taira Y Whitney F Wong SK Yoshimura T 《Nature》2004,428(6982):549-553
Iron supply has a key role in stimulating phytoplankton blooms in high-nitrate low-chlorophyll oceanic waters. However, the fate of the carbon fixed by these blooms, and how efficiently it is exported into the ocean's interior, remains largely unknown. Here we report on the decline and fate of an iron-stimulated diatom bloom in the Gulf of Alaska. The bloom terminated on day 18, following the depletion of iron and then silicic acid, after which mixed-layer particulate organic carbon (POC) concentrations declined over six days. Increased particulate silica export via sinking diatoms was recorded in sediment traps at depths between 50 and 125 m from day 21, yet increased POC export was not evident until day 24. Only a small proportion of the mixed-layer POC was intercepted by the traps, with more than half of the mixed-layer POC deficit attributable to bacterial remineralization and mesozooplankton grazing. The depletion of silicic acid and the inefficient transfer of iron-increased POC below the permanent thermocline have major implications both for the biogeochemical interpretation of times of greater iron supply in the geological past, and also for proposed geo-engineering schemes to increase oceanic carbon sequestration. 相似文献
26.
27.
Mutations in INVS encoding inversin cause nephronophthisis type 2, linking renal cystic disease to the function of primary cilia and left-right axis determination 总被引:20,自引:0,他引:20
Otto EA Schermer B Obara T O'Toole JF Hiller KS Mueller AM Ruf RG Hoefele J Beekmann F Landau D Foreman JW Goodship JA Strachan T Kispert A Wolf MT Gagnadoux MF Nivet H Antignac C Walz G Drummond IA Benzing T Hildebrandt F 《Nature genetics》2003,34(4):413-420
Nephronophthisis (NPHP), an autosomal recessive cystic kidney disease, leads to chronic renal failure in children. The genes mutated in NPHP1 and NPHP4 have been identified, and a gene locus associated with infantile nephronophthisis (NPHP2) was mapped. The kidney phenotype of NPHP2 combines clinical features of NPHP and polycystic kidney disease (PKD). Here, we identify inversin (INVS) as the gene mutated in NPHP2 with and without situs inversus. We show molecular interaction of inversin with nephrocystin, the product of the gene mutated in NPHP1 and interaction of nephrocystin with beta-tubulin, a main component of primary cilia. We show that nephrocystin, inversin and beta-tubulin colocalize to primary cilia of renal tubular cells. Furthermore, we produce a PKD-like renal cystic phenotype and randomization of heart looping by knockdown of invs expression in zebrafish. The interaction and colocalization in cilia of inversin, nephrocystin and beta-tubulin connect pathogenetic aspects of NPHP to PKD, to primary cilia function and to left-right axis determination. 相似文献
28.
Animal behaviour: insect orientation to polarized moonlight 总被引:1,自引:0,他引:1
29.
Ryanodine receptor gene is a candidate for predisposition to malignant hyperthermia 总被引:39,自引:0,他引:39
D H MacLennan C Duff F Zorzato J Fujii M Phillips R G Korneluk W Frodis B A Britt R G Worton 《Nature》1990,343(6258):559-561
Malignant hyperthermia (MH) is a potentially lethal condition in which sustained muscle contracture, with attendant hypercatabolic reactions and elevation in body temperature, are triggered by commonly used inhalational anaesthetics and skeletal muscle relaxants. In humans, the trait is usually inherited in an autosomal dominant fashion, but in halothane-sensitive pigs with a similar phenotype, inheritance of the disease is autosomal recessive or co-dominant. A simple and accurate non-invasive test for the gene is not available and predisposition to the disease is currently determined through a halothane- and/or caffeine-induced contracture test on a skeletal muscle biopsy. Because Ca2+ is the chief regulator of muscle contraction and metabolism, the primary defect in MH is believed to lie in Ca2+ regulation. Indeed, several studies indicate a defect in the Ca2+ release channel of the sarcoplasmic reticulum, making it a prime candidate for the altered gene product in predisposed individuals. We have recently cloned complementary DNA and genomic DNA encoding the human ryanodine receptor (the Ca2(+)-release channel of the sarcoplasmic reticulum) and mapped the ryanodine receptor gene (RYR) to region q13.1 of human chromosome 19 (ref. 14), in close proximity to genetic markers that have been shown to map near the MH susceptibility locus in humans and the halothane-sensitive gene in pigs. As a more definitive test of whether the RYR gene is a candidate gene for the human MH phenotype, we have carried out a linkage study with MH families to determine whether the MH phenotype segregates with chromosome 19q markers, including markers in the RYR gene. Co-segregation of MH with RYR markers, resulting in a lod score of 4.20 at a linkage distance of zero centimorgans, indicates that MH is likely to be caused by mutations in the RYR gene. 相似文献
30.
Marie Morelato Mark Barash Lucas Blanes Scott Chadwick Jessirie Dilag Unnikrishnan Kuzhiumparambil Katie D. Nizio Xanthe Spindler Sebastien Moret 《Foundations of Science》2017,22(4):799-825
Forensic science and its influence on policing and the criminal justice system have increased since the beginning of the twentieth century. While the philosophies of the forensic science pioneers remain the pillar of modern practice, rapid advances in technology and the underpinning sciences have seen an explosion in the number of disciplines and tools. Consequently, the way in which we exploit and interpret the remnant of criminal activity are adapting to this changing environment. In order to best exploit the trace, an interdisciplinary approach to both research and investigation is required. In this paper, nine postdoctoral research fellows from a multidisciplinary team discuss their vision for the future of forensic science at the crime scene, in the laboratory and beyond. This paper does not pretend to be exhaustive of all fields of forensic science, but describes a portion of the postdoctoral fellows’ interests and skills. 相似文献