检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

How plants grow up

Journal of Integrative Plant Biology 2019年第3期61卷 257-277页

作者： sarah m mcKim Division of Plant Sciences University of Dundee at The James Hutton Institute

A plant's lateral structures, such as leaves,branches and flowers, literally hinge on the shoot axis,making its integrity and growth fundamental to plant *** all plants, subapical proliferation within the shoot tip displaces cells downward to extrude the cylindrical *** the transition to flowering, many plants show extensive axial elongation associated with increased subapical proliferation and expansion. However, the cereal grasses also elongate their stems, called culms, due to activity within detached intercalary meristems which displaces cells upward, elevating the grain-bearing inflorescence. Variation in culm length within species is especially relevant to cereal crops, as demonstrated by the high-yielding semi-dwarfed cereals of the Green Revolution. Although previously understudied, recent renewed interest the regulation of subapical and intercalary growth suggests that control of cell division planes,boundary formation and temporal dynamics of differentiation, are likely critical mechanisms coordinating axial growth and development in plants.

关键词： plants grow up^FA lateral structures

Habitat structure directly affects aggression in convict cichlids Archocentrus nigrofasciatus

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2010年第1期56卷 52-56页

作者： Anthony J. BARLEY Ronald m. coleman Department of Biological Sciences California State University Sacramento California 95819-6077 USA

Aggressive behavior can be an important factor in determining how animals use and divide space and resources. Previous studies have shown that aggression in fishes can be influenced by a variety of factors, including water temperature and resource levels. In this study, we tested if the amount of habitat structure in the environment affected aggression levels in female convict cichlids Archocentrus nigrofasciatus. We performed a laboratory experiment in which we placed female convict cichlids into an aquarium with low or high amounts of habitat structure and monitored the dominant female＇s behavior toward the subordinate female. Aggressive behavior in convict cichlids primarily consists of chases and bites. We found that the total time the dominant female spent chasing the subordinate female was greater when there was a low amount of habitat structure as compared to when there was a high amount of habitat structure. We also found that both the average duration of a chasing bout and the number of bites directed at the subordinate fish increased when there was a low amount of structure, but the number of chases did not. These results indicate that increased habitat structural complexity decreases aggressive behavior in convict cichlids [Current Zoology 56 （1）： 52-56, 2010].

关键词： Neotropical Life-history Female-female competition Fish Resource competition

在线全文

学校读者我要写书评

暂无评论

禽霉形体病的防制

国外畜牧科技 1992年第2期19卷 42-43页

作者： m.coleman 查红波

目前,世界上受到霉形体(以前称支原体。—编者注)病危害的鸡只达13％以上,使其增重减少38％,饲料转化率降低21％。当鸡群中出现霉形体阳性鸡时,很难全部检出并分离饲养。随着养鸡业规模的扩大,霉形体病的防制措施也在相应变化。彻底淘... 详细信息

目前,世界上受到霉形体(以前称支原体。—编者注)病危害的鸡只达13％以上,使其增重减少38％,饲料转化率降低21％。当鸡群中出现霉形体阳性鸡时,很难全部检出并分离饲养。随着养鸡业规模的扩大,霉形体病的防制措施也在相应变化。彻底淘汰阳性鸡是防制霉形体病的基本原则。防制霉形体病的几种方法 1.彻底淘汰阳性鸡群。

关键词：家禽霉形体病防制

Comprehension of functional support by enculturated chimpanzees Pan troglodytes

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2011年第4期57卷 429-440页

作者： Anna m. YOCOm sarah T. BOYSEN Department of Psychology The Ohio State University Columbus OH 43210 USA

Studies of causal understanding of tool relationships in captive chimpanzees have yielded disparate findings, particularly those reported by Povinelli ＆ colleagues （2000） for tool tasks by laboratory chimpanzees. The present set of experiments tested nine enculturated chimpanzees on three versions of a support task, as described by Povinelli （2000）, during which food re- wards were presented in different experimental configurations. In Experiment 1, stimulus pairs included a choice between a cloth with a reward on the upper right comer or with a second reward off the cloth, adjacent to a comer, with the second pair comprised of a cloth with food on the upper right comer, and a second cloth with the reward on the substrate, partially covered. All subjects were successful with both test conditions in Experiment 1. In a second study, the experimental choices included one of two possi- ble correct options, paired with one of three incorrect options, with the three incorrect choices all involving varying degrees of perceptual containment. All nine chimpanzees scored significantly above chance across all six conditions. In Experiment 3, four unique conditions were presented, combining one of two possible correct choices with one of two incorrect choices. Six of the subjects scored significantly above chance across the four conditions, and group performance on individual conditions was also significant. Superior performance was demonstrated by female subjects in Experiment 3, similar to sex differences in tool use previously reported for wild chimpanzees and some tool tasks in captive chimpanzees. The present results for Experiments 2 ＆ 3 were significantly differed from those reported by Povinelli et al. （2000） for laboratory-born, peer-reared chimpanzees. One contribution towards the dramatic differences between the two study populations may be the significant rearing and housing differences of the chimpanzee groups. One explanation is that under conditions of enculturat

关键词： Chimpanzees Comparative cognition Tool use Causality

metabolite Transporter Regulation of ABA Function and Guard Cell Response

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

molecular Plant 2014年第10期7卷 1505-1507页

作者： Yunqing Yu sarah m. Assmann Biology Department Pennsylvania State University 208 Mueller Laboratory University Park PA 16802–5301 USA

Pairs of guard cells form stomatal pores through which gas exchange occurs. Gas exchange includes transpirational water loss, and guard cell signaling in drought response has been studied for decades. Abscisic acid （ABA） is the major hormone that regulates drought responses. ABA and other metabolites can be synthesized in one cell type or subcellular compartment and transported across mem- branes by specific transporters to conduct biological func- tions. Two new papers, both taking advantage of reverse genetic methods, one focusing on a plasma membrane ABA efflux carrier （Zhang et al., 2014） and the other on a putative mitochondrial pyruvate carrier （Li et al., 2014）, have recently shown the importance of metabolite trans- porters in ABA function and guard cell response.

关键词：

一次性使用/空间运输系统火箭轨道转移级的液体推进技术

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

上海航天 1988年第3期 24-28页

作者： K.A.Ennix m.coleman 吴素珍

分析用于各种上面级的轨道转移飞行器(OTV)最佳液体推进设计方案,研究了17.7—26t低地球轨道(LEO)级运载火箭有效载荷级用的高/低压地面可贮存推进系统技术及高性能、低推力低温推进方案.以LEO高度100nmile、比冲340s、质量比0.90为基... 详细信息

分析用于各种上面级的轨道转移飞行器(OTV)最佳液体推进设计方案,研究了17.7—26t低地球轨道(LEO)级运载火箭有效载荷级用的高/低压地面可贮存推进系统技术及高性能、低推力低温推进方案.以LEO高度100nmile、比冲340s、质量比0.90为基本标准,通过计算给出质量比在0.88—0.92及比冲在320—500s范围内的性能

关键词：运载火箭轨道发射轨道转移飞行器航天技术航天推进末级火箭发动机

Achalasia: A review of clinical diagnosis, epidemiology,treatment and outcomes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2013年第35期19卷 5806-5812页

作者： Orla m O'Neill Brian T Johnston Helen G coleman Centre for Public Health Queen’s University Belfast Department of Gastroenterology Belfast Health and Social Care Trust

Achalasia is a neurodegenerative motility disorder of the oesophagus resulting in deranged oesophageal peristalsis and loss of lower oesophageal sphincter ***,annual achalasia incidence rates were believed to be low,approximately 0.5-1.2 per *** recent reports suggest that annual incidence rates have risen to 1.6 per 100000 in some *** aetiology of achalasia is still unclear but is likely to be *** causes include environmental or viral exposures resulting in inflammation of the oesophageal myenteric plexus,which elicits an autoimmune *** of achalasia may be elevated in a sub-group of genetically susceptible *** in the diagnosis of achalasia,through the introduction of high resolution manometry with pressure topography plotting,has resulted in the development of a novel classification system for *** classification system can evaluate patient prognosis and predict responsiveness to *** is currently much debate over whether pneumatic dilatation is a superior method compared to the Heller’s myotomy procedure in the treatment of achalasia.A recent com-parative study found equal efficacy,suggesting that patient preference and local expertise should guide the *** achalasia is a relatively rare condition,it carries a risk of complications,including aspiration pneumonia and oesophageal *** risk of both squamous cell carcinoma and adenocarcinoma of the oesophagus is believed to be significantly increased in patients with achalasia,however the absolute excess risk is ***,it is currently unknown whether a surveillance programme in achalasia patients would be effective or cost-effective.

关键词： Epidemiology Achalasia Incidence Treatment Oesophageal cancer risk

microglial depletion and repopulation:a new era of regenerative medicine?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2021年第6期16卷 1204-1205页

作者： Alexandra m.Barnett Fulton T.Crews Leon G.coleman Bowles Center for Alcohol Studies The University of North Carolina at Chapel HillSchool of MedicineChapel HillNCUSA Department of Pharmacology The University of North Carolina at Chapel HillSchool of MedicineChapel HillNCUSA Department of Psychiatry The University of North Carolina School of MedicineChapel HillNCUSA

microglia have multiple functions and phenotypes that can prevent or worsen *** depletion and repopulation methods provide a promising technique for understanding microglial *** utility as therapeutic modalities is now under *** resident immune cells in the central nervous system(CNS),microglia maintain the local environment and promote neuronal ***,persistent proinflammatory signaling due to aberrant microglial activation can be *** is seen in settings such as traumatic brain injury(TBI)(Henry et al.,2020),stroke(Li et al.,2017),and alcohol use disorder(AUD)(coleman et al.,2020),when the loss of homeostatic control results in persistent proinflammatory signaling that contributes to ongoing neuropathology(Figure 1).Thus,selective replacement of chronically proinflammatory-activated microglia could improve functional outcomes.

关键词： al. pathology depletion

Why did life develop on the surface of the Earth in the Cambrian？

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2016年第6期7卷 865-873页

作者： Carlo Doglioni Johannes Pignatti max coleman Department of Earth Sciences Sapienza University 00185 Rome Italy NASA Jet Propulsion Laboratory California Institute of Technology Pasadena CA 91109 USA NASA Astrobiology Institute USA

Life was limited for most of Earth＇s history, remaining at a primitive stage and mostly marine until about 0.55 Ga. In the Paleozoic, life eventually exploded and colonized the continental realm. Why had there been such a long period of delayed evolution of life？ Early life was dominated by Archaea and Bacteria, which can survive ionizing radiation better than other organisms. The magnetic field preserves the atmosphere, which is the main shield of UV radiation. We explore the hypothesis that the Cambrian explosion of life could have been enabled by the increase of the magnetic field dipole intensity due to the solidification of the inner core, caused by the cooling of the Earth, and the concomitant decrease with time of the high-energy solar flux since the birth of the solar system. Therefore, the two phenomena could be responsible for the growth and thickening of the atmosphere and the development of land surface life.

关键词： Origin of lifeInner core solidificationSolar ionizing radiations