期刊文献+
共找到200篇文章
< 1 2 10 >
每页显示 20 50 100
Bisexual Galton-Watson Branching Processes in Random Environments 被引量:29
1
作者 Shi-xia Ma 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2006年第3期419-428,共10页
In this paper, we consider a bisexual Galton-Watson branching process whose offspring probability distribution is controlled by a random environment proccss. Some results for the probability generating functions assoc... In this paper, we consider a bisexual Galton-Watson branching process whose offspring probability distribution is controlled by a random environment proccss. Some results for the probability generating functions associated with the process are obtained and sufficient conditions for certain extinction and for non-certain extinction are established. 展开更多
关键词 bisexual Galton-Watson branching processes branching processes in random environments extinction probabilities
原文传递
Early Cretaceous Archaefructus eoflora sp. nov. with Bisexual Flowers from Beipiao, Western Liaoning, China 被引量:23
2
作者 JIQiang LIHongqi +2 位作者 L.MichelleBOWE LIUYusheng DavidWinshipTAYLOR 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第4期883-896,共14页
Recently, whether Archaefructus has bisexual multi-parted flowers or just inflorescences of unisexual flowers, and whether it is ancestral to all angiosperms or a derived eudicot have been debated. Here, from the same... Recently, whether Archaefructus has bisexual multi-parted flowers or just inflorescences of unisexual flowers, and whether it is ancestral to all angiosperms or a derived eudicot have been debated. Here, from the same Yixian Formation, NE China, we report a new Archaefructus species, A. eoflora sp. nov., with the generic characteristics of dissected leaves and bisexual reproductive axes. It is entirely preserved with roots, rhizome, shoots and protogynous reproductive organs at different developmental stages. Its lateral and main fertile shoots form a pseudo-indeterminate pattern, while the reproductive branches on the main shoot form a cymose inflorescence. Subtended by 1-2 bract-like leaves, the section of stamen clusters changes into a much shorter section of carpels that have one row of orthotropous ovules. Significantly, one cluster bearing two carpels and one stamen between the two sections demonstrates a true bisexual flower, an important step of the origin of floral bisexuality, and the homology between the stamen and carpel. The complex reproductive axes represent a mix between flowers and inflorescences, and suggest that A. eoflora sp. nov. possesses the potential to evolve into a variety of diverse flower types as found in modern basal and early fossil angiosperms. A comparison with other two species also leads to a revision of the generic diagnosis. 展开更多
关键词 Archaefructus eoflora bisexual flower fossil angiosperm orthotropous ovules plant evolution protogynous development Lower Cretaceous Yixian Formation
下载PDF
An Undercover Angiosperm from the Jurassic of China 被引量:7
3
作者 ZHENG Shaolin WANG Xin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2010年第4期895-902,共8页
Searching for early angiosperms is a riveting activity in botany because it helps to resolve the phyiogenetic relationships among seed plants and among angiosperms themselves. One of the challenges for this job is wha... Searching for early angiosperms is a riveting activity in botany because it helps to resolve the phyiogenetic relationships among seed plants and among angiosperms themselves. One of the challenges for this job is what the target fossils look like. Most possibly early angiosperms may elude our scrutiny with gymnospermous appearances. This possibility becomes a reality in a Jurassic plant, Solaranthus gen. nov, which bears a peltaspermalean appearance and enclosed ovules. According to knowledge available hitherto, the latter feature makes it an angiosperm. However, such a feature is more likely to be eclipsed by its gymnospermous appearance. The early age and unexpected character assemblage of Solaranthus urge for a fresh look on the assumed-simple relationship between angiosperms and gymnosperms. Its resemblance to the order Peltaspermales favors the Mostly Male Theory. 展开更多
关键词 bisexual FLOWER JURASSIC ANGIOSPERMS Peltaspermales Mostly Male Theory
下载PDF
光滑河蓝蛤生殖习性初步研究 被引量:8
4
作者 刘吉明 佘君同 《水产科学》 CAS 北大核心 2003年第5期12-13,共2页
光滑河蓝蛤一年有2次产卵高峰期,分别为在5月初和9月底。在产卵高峰期,通过人工授精方法,可获得受精卵并正常发育。在秋季性腺切片中发现1例雌性滤泡周围有呈集中式分散状态分布的精子,经分析初步认定是雌雄同体现象。
关键词 光滑河蓝蛤 生殖习性 产卵高峰期 雌雄同体 饵料生物
下载PDF
FORM ERROR EVALUATION OF CIRCLES BASED ON A FINELY-DESIGNED GENETIC ALGORITHM 被引量:5
5
作者 CuiChangcai CheRensheng LiZhongyan YeDong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第1期59-62,共4页
A genetic algorithm(GA)-based new method is designed to evaluate thecircularity error of mechanical parts. The method uses the capability of nonlinear optimization ofGA to search for the optimal solution of circularit... A genetic algorithm(GA)-based new method is designed to evaluate thecircularity error of mechanical parts. The method uses the capability of nonlinear optimization ofGA to search for the optimal solution of circularity error. The finely-designed GA (FDGA)characterized dynamical bisexual recombination and Gaussian mutation. The mathematical model of thenonlinear problem is given. The implementation details in FDGA are described such as the crossoveror recombination mechanism which utilized a bisexual reproduction scheme and the elitist reservationmethod; and the adaptive mutation which used the Gaussian probability distribution to determine thevalues of the offspring produced by mutation mechanism. The examples are provided to verify thedesigned FDGA. The computation results indicate that the FDGA works very well in the field of formerror evaluation such as circularity evaluation. 展开更多
关键词 Genetic algorithm(GA) Form error CIRCULARITY bisexual recombination Gaussian mutation
下载PDF
The Earliest Normal Flower from Liaoning Province, China 被引量:4
6
作者 Xin Wang Shaolin Zheng 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2009年第8期800-811,共12页
The early evolution of angiosperms has been a focus of intensive research for more than a century. The Yixian Formation in western Liaoning yields one of the earliest angiosperm macrofioras. Despite multitudes of angi... The early evolution of angiosperms has been a focus of intensive research for more than a century. The Yixian Formation in western Liaoning yields one of the earliest angiosperm macrofioras. Despite multitudes of angiosperm fossils uncovered, including Archaefructus and Sinocarpus, no bona fide normal flower has been dated to 125 Ma (mega-annum) or older. Here we report Callianthus dilae gen. et sp. nov. from the Yixian Formation (Early Cretaceous) in western Liaoning, China as the earliest normal flower known to date. The flower demonstrates a typical floral organization, including tepals, androecium, and gynoecium. The tepals are spatulate with parallel veins. The stamens have a slender filament, a globular anther, bristles at the anther apex, and in situ round-triangular pollen grains. The gynoecium is composed of two stylate carpels enclosed in a fleshy envelope, and develops into a "hip" when mature. Since the well-accepted history of angiosperms is not much longer than 125 Ma, Callianthus together with Chaoyangia, Archaefructus and Sinocarpus from the Yixian Formation demonstrate a surprisingly high diversity of angiosperms, implying a history of angiosperms much longer than currently accepted. 展开更多
关键词 ANGIOSPERM bisexual Callianthus Early Cretaceous FLOWER LIAONING PERIANTH Yixian Formation
原文传递
基于张景岳《宜麟策》探析药食对两性嗣育影响
7
作者 肖正 李应存 +2 位作者 马骏 季文达 顾晓霞 《中国中医药图书情报杂志》 2024年第4期15-18,共4页
药物和饮食是影响男女嗣育的两大重要因素。明代医家张景岳于《宜麟策》一文中,详细探讨药食对两性胎孕期间的相关作用,其中药物部分包含辨证挑选男女种子之方、药物剂型调整、张景岳对香附的独特见解,饮食部分包括男子饮酒伤胎、妇女... 药物和饮食是影响男女嗣育的两大重要因素。明代医家张景岳于《宜麟策》一文中,详细探讨药食对两性胎孕期间的相关作用,其中药物部分包含辨证挑选男女种子之方、药物剂型调整、张景岳对香附的独特见解,饮食部分包括男子饮酒伤胎、妇女饮食禁忌等学术论点。本文探析药物、饮食对男女嗣育之影响,深入研究张景岳对中医生殖学的全面见解,以期对两性优生优育提供理论支持。 展开更多
关键词 张景岳 两性 食疗 孕育
下载PDF
Molecular Phylogeny of Bisexual Artemia Based on 16S rDNA 被引量:5
8
作者 印红 关妮 付育婷 《Agricultural Science & Technology》 CAS 2011年第5期659-662,共4页
[Objective] The research aimed at investigating the taxonomic position and phylogenetic relationship of bisexual brine shrimps.[Method] 16S rDNA of three species of bisexual Artemia from China was determined;the homol... [Objective] The research aimed at investigating the taxonomic position and phylogenetic relationship of bisexual brine shrimps.[Method] 16S rDNA of three species of bisexual Artemia from China was determined;the homologous sequences between them and 11 relative species of Artemia from GenBank were compared;the molecular phylogenetic tree was constructed by Mega Microsoft using Artemiopsis stefanssoni as outgroup.[Result] Artemia persimilis was the primal group in genus Artemia;Artemia franciscana and Artemia monica were the evolved groups;Artemia urmiana,Artemia sinica and other Artemia species from China shared a close genetic relationship.[Conclusion] Based on the 16S rDNA sequence of them,the phylogenetic relationships of these bisexual Artemia species were A.persimilis→A.urmiana,A.sinica and A.tibetiana→A.tunisiana→A.monica→A.Franciscan. 展开更多
关键词 bisexual Artemia 16S rDNA Molecular phylogeny
下载PDF
Health-related attitudes and risk factors for sexually transmitted infections of Chinese women who have sex with women 被引量:2
9
作者 WANG Xiao-fang Jessie L. Norris +2 位作者 LIUYingjie Kathleen H. Reilly WANG Ning 《Chinese Medical Journal》 SCIE CAS CSCD 2012年第16期2819-2825,共7页
Background Previous studies have shown evidence of health-related risk behaviors among women who have sex with women (WSW), such as sex with men, multiple bisexual partners, and drug use. Women who have sex with wom... Background Previous studies have shown evidence of health-related risk behaviors among women who have sex with women (WSW), such as sex with men, multiple bisexual partners, and drug use. Women who have sex with women have also been known to avoid routine physical examinations and conceal their same-sex history from physicians, which can affect their ability to receive an accurate diagnosis and treatment. No previous research has targeted women who have sex with women in China. We sought to describe women who have sex with women in China and explore risk factors for their reproductive tract infections (RTI)/sexually transmitted infections (STI). Methods Participants were recruited through outreach in venues and online for a cross-sectional study. Data were collected using interviews and laboratory tests. Results We recruited 224 women who have sex with women. In the year preceding their participation in the study, 92% (206/224) of women reported sexual relations with women. The RTI rates were: gonorrhea (15.8%), chlamydia (3.5%), syphilis (0.5%), bacterial vaginosis (14.4%), hepatitis B virus (HBV) (0.9%), hepatitis C virus (HCV) (0.5%), and candidiasis (6.9%). No HIV or herpes simplex virus (HSV) positive cases were detected. Factors associated with gonorrhea infection were non-Beijing local residency (odds ratio (OR)=2.1, 95% confidence interval (C/): 1.2-3.8) and genital-genital contact (OR=3.1, 95% CI: 1.3-7.2); factors associated with curable STI (excluding bacterial vaginosis, candidiasis, HBV and HCV) were non-Beijing local residency (OR=1.9; 95% CI: 1.2-3.0) and bleeding during or after sex (OR=18.1; 95% CI: 5.2-62.6); and the factor associated with RTI (including all the infections tested) was bleeding during or after sex (OR=37.8, 95% CI: 11.2-127.4). Conclusions Behaviors that may cause RTI/STI exist among Chinese women who have sex with women. Researchers should consider these behaviors when plannin 展开更多
关键词 women who have sex with women lesbian gay bisexual transgender HIV/AIDS sexual transmission sexually transmitted infection
原文传递
THE ASYMPTOTIC PROPERTIES OF SUPERCRITICAL BISEXUAL GALTON-WATSON BRANCHING PROCESSES WITH IMMIGRATION OF MATING UNITS 被引量:1
10
作者 马世霞 邢永胜 《Acta Mathematica Scientia》 SCIE CSCD 2006年第4期603-609,共7页
In this article the supercritical bisexual Galton-Watson branching processes with the immigration of mating units is considered. A necessary condition for the almost sure convergence, and a sufficient condition for th... In this article the supercritical bisexual Galton-Watson branching processes with the immigration of mating units is considered. A necessary condition for the almost sure convergence, and a sufficient condition for the L^1 convergence are given for the process with the suitably normed condition. 展开更多
关键词 bisexual Galton-Watson branching processes IMMIGRATION almost sure convergence L^1-convergence
下载PDF
ON THE EXTINCTION OF POPULATION-SIZE-DEPENDENT BISEXUAL GALTON-WATSON PROCESSES 被引量:1
11
作者 邢永胜 王学强 《Acta Mathematica Scientia》 SCIE CSCD 2008年第1期210-216,共7页
In this article, the population-size-dependent bisexual Galton-Watson processes are considered. Under some suitable conditions on the mating functions and the offspring distribution, existence of the limit of mean gro... In this article, the population-size-dependent bisexual Galton-Watson processes are considered. Under some suitable conditions on the mating functions and the offspring distribution, existence of the limit of mean growth rate per mating unit is proved. And based on the limit, a criterion to identify whether the process admits ultimate extinct with probability one is obtained. 展开更多
关键词 bisexual Galton-Watson branching processes population-size-dependent branching processes extinction probability
下载PDF
幼儿双性化发展初探 被引量:3
12
作者 张晗 《山东英才学院学报》 2009年第4期14-17,共4页
人一出生便被分别纳入由社会规范好的两性(男性和女性)范畴。幼儿期是人掌握性别概念、形成良好性别角色特征的初始阶段和关键时期,而能否形成良好的性别角色特征关系到人一生的性别角色发展,也会影响到一生的幸福。本文采用BEM性别角... 人一出生便被分别纳入由社会规范好的两性(男性和女性)范畴。幼儿期是人掌握性别概念、形成良好性别角色特征的初始阶段和关键时期,而能否形成良好的性别角色特征关系到人一生的性别角色发展,也会影响到一生的幸福。本文采用BEM性别角色量表对幼儿双性化发展进行了初步的探讨,并提出教育建议。 展开更多
关键词 幼儿 双性化 性别角色
原文传递
A.S.Convergence Rate and L^(p)-Convergence of Bisexual Branching Processes in a Random Environment and Varying Environment
13
作者 Sheng XIAO Xiang-dong LIU Ying-qiu LI 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2023年第2期337-353,共17页
Let(Z_(n))be a supercritical bisexual branching process in a random environmentξ.We study the almost sure(a.s.)convergence rate of the submartingale W_(n)=Z_(n)/In to its limit W,where(In)is an usually used norming s... Let(Z_(n))be a supercritical bisexual branching process in a random environmentξ.We study the almost sure(a.s.)convergence rate of the submartingale W_(n)=Z_(n)/In to its limit W,where(In)is an usually used norming sequence.We prove that under a moment condition of order p∈(1,2),W-W_(n)=o(e^(-na))a.s.for some a>0 that we find explicitly;assuming the logarithmic moment condition holds,we haveW-W_(n)=o(n^(-α))a.s..In order to obtain these results,we provide the L^(p)-convergence of(W_(n));similar conclusions hold for a bisexual branching process in a varying environment. 展开更多
关键词 bisexual branching process convergence rate varying environment random environment
原文传递
有自杀意念的男同性爱者/双性爱者艾滋病高危行为研究 被引量:4
14
作者 陈宏泉 李洋 +1 位作者 张北川 李秀芳 《中华流行病学杂志》 CAS CSCD 北大核心 2011年第10期983-986,共4页
目的探讨男同性爱者(gay)与双性爱者(Bi)中有自杀意念者的艾滋病高危行为特征,并分析其与自杀意念相关的危险因素。方法采用定向抽样法对gay/Bi人群进行横断面调查。从有效问卷中获取有自杀意念者,并依照自杀意念组的年龄隋况在... 目的探讨男同性爱者(gay)与双性爱者(Bi)中有自杀意念者的艾滋病高危行为特征,并分析其与自杀意念相关的危险因素。方法采用定向抽样法对gay/Bi人群进行横断面调查。从有效问卷中获取有自杀意念者,并依照自杀意念组的年龄隋况在无此意念者中选取比较组进行比较。结果调查的gay/Bi中有自杀意念者占20.2%。自杀意念组性向为同性、婚姻状况为未婚者多于比较组(P〈0.05)。自杀意念组在曾经向同性买性、近一年性交时曾出过血、曾去外地与陌生同性性交、16岁前曾遭受成年同性性虐待、有性施虐与受虐行为、有过主动或被动吻肛行为、有过主动或被动指交行为、每周饮酒至少一次或更多、曾因性向和/或同性性活动受到gay伤害、曾因性向和/或同性性活动受到异性爱者伤害等方面的比例显著高于对照组(P〈0.05)。多因素logistic回归模型提示曾因性向和/或同性性活动受到gay(WaldX^2=6.637,P=0.010)及异性爱者(IValdX^2=5.835,P=0.016)伤害是导致自杀意念产生的危险因素。结论有自杀意念的gay/Bi与艾滋病相关的高危性行为显著多于无此意念者。减少社会对gay与Bi人群的歧视及伤害可能对遏制艾滋病的流行有一定作用。 展开更多
关键词 同性爱 双性爱 自杀意念 高危行为 艾滋病
原文传递
Anal Cancer in a HIV Sero-Positive Bisexual Bachelor—A Case Report and Literature Review
15
作者 Victor Nwagbara M. E. Asuquo +1 位作者 J. A. Ashindoitiang S. O. Akpan 《Case Reports in Clinical Medicine》 2018年第12期601-607,共7页
Anal cancer, especially squamous cell carcinoma (SCC) variety, is evolving with rising incidence globally. This is due to the increasing adoption of risky life styles and social habits even in populations with rare oc... Anal cancer, especially squamous cell carcinoma (SCC) variety, is evolving with rising incidence globally. This is due to the increasing adoption of risky life styles and social habits even in populations with rare occurrences previously. This case report aims to expose risk factors exhibited by a patient recently managed for anal cancer in our facility before his demise. Early exposure to bisexual orientation, receptive anal intercourse and multiple sexual partners, are notable high risk factors for the development of anal SCC. The permissive role of smoking, illicit drug and alcohol use enhances the disease occurrence. Acquisition of human immune-deficiency virus (HIV) sero-positive status further reduces the body’s immune competence and enhances early age of onset as well as accelerates development of anal SCC. Proper history exploring the risk factors, physical/anorectal examination and histological analysis, are vital for proper diagnosis and staging which guides appropriate treatment with chemo-radiation as mainstay. 展开更多
关键词 ANAL Cancer bisexual Human Immune-Deficiency Virus Sero-Positive Status SQUAMOUS Cell Carcinoma
下载PDF
The Stressors and Psychological Well-Being of Lesbian, Gay and Bisexual among Chinese Adults in Hong Kong
16
作者 Lai Sheung Winnie Cheng 《Journal of Biosciences and Medicines》 2019年第5期65-70,共6页
Background: Lesbian, Gay and Bisexual (LGB) are individuals who often experienced stigma and discrimination which has detrimental effects on psychological well-being. Objectives: This study aimed to identify the major... Background: Lesbian, Gay and Bisexual (LGB) are individuals who often experienced stigma and discrimination which has detrimental effects on psychological well-being. Objectives: This study aimed to identify the major stressors and psychological well-being of LGB among Chinese adults in Hong Kong. Methods: A cross-sectional study was employed using self-administered questionnaires. Convenience sampling was used to recruit subjects. Demographic information, Measure of Gay-related stress (MOGS) and The Center for Epidemiologic Studies Depression Scale (CES-D Scale) were used to collect data. Results: The major stressor among LGB individuals in Hong Kong was family reaction. Majority of them had a high level of depression. Conclusion: LGB individuals in Hong Kong experienced high level of depression. 展开更多
关键词 LESBIAN GAY and bisexual DEPRESSION Sexual MINORITY MINORITY Stress
下载PDF
带某类配对函数的两性分支过程 被引量:1
17
作者 王勇 《太原理工大学学报》 CAS 2003年第6期753-755,共3页
利用概率母函数,对带有取值恒等于雌性数目的配对函数的两性Galton Watson分支过程,给出了其以概率1灭绝的充分必要条件,并求得了相应的数学期望与方差的表达式。
关键词 分支过程 两性 灭绝概率
下载PDF
Dispersal patterns in Yunnan snub-nosed monkeys 被引量:1
18
作者 Wancai XIA Fan WANG +5 位作者 Dali WANG Xiaoqin ZENG Chan YANG Ali KRZTON Baoping REN Dayong LI 《Current Zoology》 SCIE CAS CSCD 2022年第3期265-273,共9页
Sex-biased dispersal is common in group-living animals.Due to differences in local demographic and environmental factors,sex-biased dispersal presents many irregular patterns.In this study,a habituated,individually id... Sex-biased dispersal is common in group-living animals.Due to differences in local demographic and environmental factors,sex-biased dispersal presents many irregular patterns.In this study,a habituated,individually identified Yunnan snub-nosed monkey Rhinopithecus bieti group was observed over 9 years;192 dispersal events,including 97 male dispersal events(25 natal dispersal and 72 secondary dispersal)and 95 female dispersal events(34 natal dispersal and 61 secondary dispersal)were observed.Males and females showed different dispersal paths,dispersal ages,and dispersal patterns.Females had 2 dispersal paths,whereas males had 4 paths.In terms of age of dispersal,the male age of natal dispersal was younger than for females.Males prefer single dispersal,whereas females prefer parallel dispersal.Our study indicates that the dispersal pattern of R.bieti should be classified as a bisexual dispersal pattern.The differences in dispersal path,average age at dispersal,and dispersal path pattern indicate that Yunnan snub-nosed monkeys may still retain a loose matrilineal social system. 展开更多
关键词 bisexual dispersal dispersal parallel dispersal Rhinopithecus bieti
原文传递
从张景岳《宜麟策》试论地利对两性生殖的影响 被引量:1
19
作者 肖正 段永强 +3 位作者 齐菁 白敏 马骏 王斑 《中国民族民间医药》 2022年第15期13-15,共3页
明代著名医家张景岳撰写《宜麟策》一篇,其中关于地利因素对两性生殖影响的论述所涉领域广泛,颇具新意,该部分主要从地利和基址两部分展开,涉及两性交合场所的选择、孕妇体质的宜忌、男女孕育年龄与条件的成熟与否等,相关理论对现代优... 明代著名医家张景岳撰写《宜麟策》一篇,其中关于地利因素对两性生殖影响的论述所涉领域广泛,颇具新意,该部分主要从地利和基址两部分展开,涉及两性交合场所的选择、孕妇体质的宜忌、男女孕育年龄与条件的成熟与否等,相关理论对现代优生优育学有所启示。文章旨在探析地利因素对两性关系的影响,并深入研究张景岳对中医生殖学的全面的见解,以期从前人论述中获取对两性优生优育有益启迪。 展开更多
关键词 张景岳 两性 地利
下载PDF
大学生同居的法律问题与对策
20
作者 周鑫 黄哲 《西部现代职业教育研究》 2022年第2期68-73,共6页
现在大学生在校恋爱期间或多或少的存在着同居的现象,这并不是什么新鲜事情。大学生无论是从身体上还是心理上都已经成熟,他们是成年人也是有完全责任能力的公民,同样他们的恋爱也是正处于大学阶段。在校大学生同居是个人隐私方面的问题... 现在大学生在校恋爱期间或多或少的存在着同居的现象,这并不是什么新鲜事情。大学生无论是从身体上还是心理上都已经成熟,他们是成年人也是有完全责任能力的公民,同样他们的恋爱也是正处于大学阶段。在校大学生同居是个人隐私方面的问题,双方完全可以自主选择。但是,大学生在校选择同居的时候,不仅仅只是为了自己获得愉悦和快感的同时,也应该要保护好自己,不能只为了一时的激情,而忽视了责任感和恋爱的情感。本文就如何从法律的角度来分析大学生同居现象中如何保护自身合法权益,对于大学生而言,有必要认真思考同居的相关因素。 展开更多
关键词 大学生 同居 高校 两性
下载PDF
上一页 1 2 10 下一页 到第
使用帮助 返回顶部