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Current Zoology 2018年第1期64卷 89-99页

作者： peter D. DIJKSTRA Shana e. BORDeR Department of Biology Central Michigan University Mount Pleasant MI 48859 USA

Natural selection has been shown to drive population differentiation and speciation. The role of sexual selection in this process is controversial; however, most of the work has centered on mate choice while the role of male-male competition in speciation is relatively understudied. Here, we outline how male-male competition can be a source of diversifying selection on male competitive phenotypes, and how this can contribute to the evolution of reproductive isolation. We highlight how negative frequency-dependent selection (advantage of rare phenotype arising from stronger male-male competition between similar male phenotypes compared with dissimilar male phenotypes) and disruptive selection (advantage of extreme phenotypes) drives the evolution of diversity in competitive traits such as weapon size, nuptial coloration, or aggressiveness. We underscore that male-male competition interacts with other life-history functions and that variable male competitive phenotypes may represent alternative adaptive options. In addition to competition for mates, aggressive interference competition for ecological resources can exert selection on competitor signals. We call for a better integration of male-male competition with ecological interference competition since both can influence the process of speciation via comparable but distinct mechanisms. Altogether, we present a more comprehensive framework for studying the role of male-male competition in speciation, and emphasize the need for better integration of insights gained from other fields studying the evolutionary, behavioral, and physiological consequences of agonistic interactions.

关键词：男性竞争分裂频率否定形成期配偶选择自然选择

Possibilities and concerns of implementing precision agriculture technologies on small farms in Slovenia

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International Journal of Agricultural and Biological engineering 2022年第3期15卷 16-21页

作者： Jurij Rakun erik Rihter Damijan Kelc Stajnko Denis peter Vindiš peter Berk peter Polič Miran Lakota Faculty of Agriculture and Life Sciences University of MariborPivola 102311 HočeSlovenia

Precision agriculture(PA)through the use and utilization of innovative technologies is a concept in agricultural management that enables long-term efficiency gains,control of unforeseen changes,and a reduction of negative impacts on the environment.However,there are even more reasons and benefits to using precision agriculture technologies(PATs)on farms,but the actual use on small farms is often questionable.The main objective of this research was to evaluate and analyze the current state of PA and its potential on a set of small farms.In addition,a comparison was made between small farms located in less favored areas(LFAs)and more favored areas(MFAs)to find if specific characteristics of the surrounding environment affect the(non-)implementation of these technologies by farm owners,with respect to the given regional possibilities.The result shows that 57.5%of respondents on these farms have never implemented PATs before and 20%are beginners in their respective fields.It was found that there were no statistically significant differences in the integration between fewer LFAs and MFAs technologies and their use in this study.The majority of respondents believe that the main changes need to occur on the level of politics.The results show that the level of cost or initial investment is the main reason and the main obstacle in the implementation of PATs on the surveyed farms.

关键词： precision agriculture small farm technological innovations implementation situation overview survey ICT

Deletion or underexpression of the Y-chromosome genes CDY2 and HSFY is associated with maturation arrest in American men with nonobstructive azoospermia

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Asian Journal of Andrology 2012年第5期14卷 676-682页

作者： peter J Stahl Anna N Mielnik Christopher e Barbieri peter N Schlegel Darius A Paduch Department of Urology Weill Cornell Medical CollegeNew York Presbyterian HospitaI-CornellNew YorkNY 10065USA

Maturation arrest （MA） refers to failure of germ cell development leading to clinical nonobstructive azoospermia. Although the azoospermic factor （AZF） region of the human Y chromosome is clearly implicated in some cases, thus far very little is known about which individual Y-chromosome genes are important for complete male germ cell development. We sought to identify single genes on the Y chromosome that may be implicated in the pathogenesis of nonobstructive azoospermia associated with MA in the American population. Genotype-phenotype analysis of 132 men with Y-chromosome microdeletions was performed. Protein-coding genes associated with MA were identified by visual analysis of a genotype-phenotype map. Genes associated with MA were selected as those genes within a segment of the Y chromosome that, when completely or partially deleted, were always associated with MA and absence of retrievable testicular sperm. expression of each identified gene transcript was then measured with quantitative RT-PCR in testicular tissue from separate cohorts of patients with idiopathic MA and obstructive azoospermia. Ten candidate genes for association with MA were identified within an 8.4-Mb segment of the Y chromosome overlapping the AZFb region. CDY2and HSFYwere the only identified genes for which differences in expression were observed between the MA and obstructive azoospermia cohorts. Men with obstructive azoospermia had 12-fold higher relative expression of CDY2transcript （1.33__.0.40 vs. 0.11＋_0.04; P=O.O003） and 16-fold higher expression of HSFYtranscript （0.78__.0.32 vs. 0.05_0.02; P=O.O005） compared to men with MA. CDY2 and HSFYwere also underexpressed in patients with Sertoli cell only syndrome. These data indicate that CDY2and HSFYare located within a segment of the Y chromosome that is important for sperm maturation, and are underexpressed in testicular tissue derived from men with MA. These observations suggest that impairments in CDY2 or HSFYexpression could be implicated in the pathogenesis of MA.

关键词： CDY1 protein CDY2 protein genetics histology HSFY human make infertility nonobstructive azoospermia spermato-genesis sperm maturation

昆阳磷矿不同植被恢复模式对土壤理化性质和细菌群落的影响

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植物分类与资源学报 2014年第4期36卷 514-522页

作者：李春李云驹 mortimer peter e. 许建初中国科学院昆明植物研究所资源植物与生物技术重点实验室云南昆明650201 中国科学院大学北京100049 国家磷资源开发利用工程技术研究中心云南磷化集团有限公司云南昆明650600 世界农用林业中心东亚分部云南昆明650201

土壤微生物在物质循环过程中具有重要作用且对环境变化敏感,是衡量土壤质量的重要指标,在恢复生态学研究中具有重要意义。为探究不同植被恢复模式对土壤理化性质和细菌群落的影响以及土壤细菌群落差异的原因,本研究以云南省昆阳磷矿为... 详细信息

土壤微生物在物质循环过程中具有重要作用且对环境变化敏感,是衡量土壤质量的重要指标,在恢复生态学研究中具有重要意义。为探究不同植被恢复模式对土壤理化性质和细菌群落的影响以及土壤细菌群落差异的原因,本研究以云南省昆阳磷矿为研究对象,运用PCR-DGGe技术和理化指标测定分析了三种植被恢复模式(芒草丛、旱冬瓜藏柏麻栎混交林、藏柏旱冬瓜混交林)下土壤细菌群落多样性、物种组成及土壤理化性质。结果表明:(1)植被恢复有助于改善土壤养分,不同植被恢复模式下土壤理化性质以及细菌群落多样性和物种组成均存在差异。(2)土壤细菌多样性与植被恢复模式之间具有显著相关性,但与土壤理化指标均无显著相关性。(3)土壤细菌群落物种组成与土壤碱解氮含量以及植被恢复模式间具有极显著相关性,与其他土壤理化指标间无显著相关性。本研究表明磷矿区不同植被恢复模式下土壤理化性质和细菌群落均具有差异,土壤细菌群落多样性差异的主要原因为植被恢复模式不同,物种组成差异的主要原因为土壤碱解氮含量不同,其次为植被恢复模式不同。

关键词：磷矿植被恢复模式土壤理化性质土壤细菌群落 PCR-DGGe

effective rural electrification via optimal network: Optimal path-finding in highly anisotropic search space using multiplier-accelerated A* algorithm

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能源与人工智能(英文)

能源与人工智能(英文) 2022年第1期7卷 1-17页

作者： Jerry CFLi Daniel Zimmerle peter MYoung Colorado State University United States

United Nations’7th Sustainable Development Goal envisions the availability of modern energy for everyone by 2030.While the progress has been satisfactory in the last few years,further rural electrification is increasingly challenging.The current mainstream approach of electrifying villages individually is becoming cost-ineffective due to uncertainties in both resource availability and energy demand for small,difficult-to-reach,residences.A networked rural electrification model,i.e.a cost-optimized network connecting villages and generation facilities,could improve resources utilization,reliability and flexibility.However,determining optimal paths with common search algorithms is extremely inefficient due to complex topographic features of rural areas.This work develops and applies an artificial intelligence search method to efficiently route inter-village power connections in the common rural electrification situation where substantial topological variations exist.The method is evolved from the canonical A*algorithm.Results compare favorably with optimal A*results,at significantly reduced computational effort.Furthermore,users can adaptively trade-off between computation speed and optimality and hence quickly evaluate sites and configurations at reasonable accuracy,which is impossible with classical methods.

关键词： A*routing Optimal path finding System optimization Rural electrification Sustainable development goals SDG7 energy utilization

A new mixed agent-based network and compartmental simulation framework for joint modeling of related infectious diseases-application to sexually transmitted infections

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Infectious Disease Modelling 2023年第1期8卷 84-100页

作者： Chaitra Gopalappa Hari Balasubramanian peter J.Haas University of Massachusetts Amherst 160 Governors DriveAmherstMA01003USA

Background:A model that jointly simulates infectious diseases with common modes of transmission can serve as a decision-analytic tool to identify optimal intervention combinations for overall disease prevention.In the United States,sexually transmitted infections(STIs)are a huge economic burden,with a large fraction of the burden attributed to HIV.Data also show interactions between HIV and other sexually transmitted infections(STIs),such as higher risk of acquisition and progression of co-infections among persons with HIV compared to persons without.However,given the wide range in prevalence and incidence burdens of STIs,current compartmental or agent-based network simulation methods alone are insufficient or computationally burdensome for joint disease modeling.Further,causal factors for higher risk of coinfection could be both behavioral(i.e.,compounding effects of individual behaviors,network structures,and care behaviors)and biological(i.e.,presence of one disease can biologically increase the risk of another).However,the data on the fraction attributed to each are limited.Methods:We present a new mixed agent-based compartmental(MAC)framework for jointly modeling STIs.It uses a combination of a new agent-based evolving network modeling(ABeNM)technique for lower-prevalence diseases and compartmental modeling for higher-prevalence diseases.As a demonstration,we applied MAC to simulate lower-prevalence HIV in the United States and a higher-prevalence hypothetical Disease 2,using a range of transmission and progression rates to generate burdens replicative of the wide range of STIs.We simulated sexual transmissions among heterosexual males,heterosexual females,and men who have sex with men(men only and men and women).Setting the biological risk of co-infection to zero,we conducted numerical analyses to evaluate the influence of behavioral factors alone on disease dynamics.Results:The contribution of behavioral factors to risk of coinfection was sensitive to disease burden,care access,and population heterogeneity

关键词： Joint-modeling diseases Multi-disease modeling Simulation modeling HIV and STIs Diseases and social determinants SDOH

Claudin-11 and occludin are major contributors to Sertoli cell tight junction function, in vitro

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Asian Journal of Andrology 2016年第4期18卷 620-626页

作者： Mark J McCabe Caroline FH Foo Marcel e Dinger peter M Smooker peter G Stanton Male Fertility Regulation Laboratory Hudson Institute of Medical Research Monash Medical Centre Clayton Victoria 3168 Australia School of Applied Sciences Royal Melbourne Institute of Technology University Bundoora Victoria 3088 Australia Kinghorn Centre for Clinical Genomics Garvan Institute of Medical Research Darlinghurst New South Wales 2010 Australia St Vincent's Clinical School UNSW Sydney New South Wales 2052 Australia.

The Sertoli cell tight junction （T J） is the key component of the blood-testis barrier, where it sequesters developing germ cells undergoing spermatogenesis within the seminiferous tubules. Hormonally regulated claudin-11 is a critical transmembrane protein involved in barrier function and its murine knockout results in infertility. We aimed to assess quantitatively the significance of the contribution of claudin-11 to TJ function, in vitro, using siRNA-mediated gene silencing. We also conducted an analysis of the contribution of occludin, another intrinsic transmembrane protein of the TJ. Silencing of claudin-11 and/or occludin was conducted using siRNA in an immature rat Sertoli cell culture model. Transepithelial electrical resistance was used to assess quantitatively TJ function throughout the culture. Two days after siRNA treatment, cells were fixed for immunocytochemical localization of junction proteins or lyzed for RT-PCR assessment of mRNA expression. Silencing of claudin-11, occludin, or both resulted in significant decreases in TJ function of 55% （P 〈 0.01）, 51% （P 〈 0.01）, and 62% （P 〈 0.01）, respectively. Data were concomitant with significant decreases in mRNA expression and marked reductions in the localization of targeted proteins to the Sertoli cell TJ. We provide quantitative evidence that claudin-11 contributes significantly （P 〈 0.01） to Sertoli cell TJ function in vitro. Interestingly, occludin, which is hormonally regulated but not implicated in infertility until late adulthood, is also a significant （P 〈 0.01） contributor to barrier function. Our data are consistent with in vivo studies that clearly demonstrate a role for these proteins in maintaining normal TJ barrier structure and function.

关键词： blood-testis barrier claudin-11 occludin Sertoli cell tight junction siRNA

Chemical Kinetics and Mechanism

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Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

丛书名： The Molecular World

2002年

作者： M mortimer P G Taylor

ISBN: (数字)9781847557803

ISBN: (纸本)9780854046706

Chemical Kinetics and Mechanism considers the role of rate of reaction. It begins by introducing chemical kinetics and the analysis of reaction mechanism, from basic well-established concepts to leading edge research. Organic reaction mechanisms are then discussed, encompassing curly arrows, nucleophilic substitution and e1 and e2 elimination reactions. The book concludes with a Case Study on Zeolites, which examines their structure and internal dimensions in relation to their behaviour as molecular sieves and catalysts. The accompanying CD-ROM contains the "Kinetics Toolkit", a graph-plotting application designed for manipulation and analysis of kinetic data, which is built into many of the examples, questions and exercises in the text. There are also interactive activities illustrating reaction mechanisms. The Molecular World series provides an integrated introduction to all branches of chemistry for both students wishing to specialise and those wishing to gain a broad understanding of chemistry and its relevance to the everyday world and to other areas of science. The books, with their Case Studies and accompanying multi-media interactive CD-ROMs, will also provide valuable resource material for teachers and lecturers. (The CD-ROMs are designed for use on a PC running Windows 95, 98, Me or 2000.)

关键词： Chemical kinetics.

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Petroleum Science 2017年第2期14卷 412-423页

作者： Mehdi Habibpour peter e. Clark School of Chemical engineering Oklahoma State University Stillwater OK 74078 USA

Partially hydrolyzed polyacrylamide（HPAM）as the main component of slickwater fracturing fluid is a shear-sensitive polymer,which suffers from mechanical degradation at turbulent flow rates.Five different concentrations of HPAM as well as mixtures of polyacrylamide/xanthan gum were prepared to investigate the possibility of improving shear stability of HPAM.Drag reduction（DR）measurements were performed in a closed flow loop.For HPAM solutions,the extent of DR increased from 30%to67%with increasing HPAM concentration from 100 to1000 wppm.All the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing period.Results indicated that the resistance to shear degradation increased with increasing polymer concentration.DR efficiency of 600 wppm xanthan gum（XG）was 38%,indicating that XG was not as good a drag reducer as HPAM.But with only 6%DR decline,XG solution exhibited a better shear stability compared to HPAM solutions.Mixed HPAM/XG solutions initially exhibited greater DR（40%and 55%）compared to XG,but due to shear degradation,DR%dropped for HPAM/XG solutions.Compared to 200 wppm HPAM solution,addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/XG mixed polymer solutions.

关键词： Slickwater Polyacrylamide Xanthan gum Drag reduction Shear stability

On environmental threats to male infertility

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Asian Journal of Andrology 2013年第2期15卷 199-200,I0005页

作者： Allen J Wilcox Jens peter e Bonde epidemiology Branch National Institute of Environmental Health Sciences Durham NC 27709-2233 USA Department of Occupational and environmental Medicine University Hospital of Copenhagen Copenhagen NV DK-2400 Denmark

The possibility that environmental pollutants damage human fertility is a topic of both public concern and scientific interest. The effect of environmental factors on male fertility （semen parameters） has been a special focus, stimulated in part by the dramatic damage inflicted by the pcstlcide DBCP on testicular function. extensive searches for testicular toxicants （in particular, the proposed effects of endocrine-disrupting compounds through fetal exposure） have produced little hard evidence of impairment in humans. This scarcity of evidence may reflect the difficultles of studying human fertility. Future fertifity studies should consider the wide spectrum of environmental exposures that plausibly affect reproduction.

关键词： TeSTICULAR DYSGeNeSIS SYNDROMe IN-UTeRO eXPOSURe SPeRM COUNTS SeMeN QUALITY eNDOCRINe DISRUPTION RePRODUCTIVe-TRACT FeRTILITY PReGNANCY PHTHALATe SMOKING