Basal metabolic rate and energetics of reproduction in therian mammals

Traditionally, the fact that reproduction in eutherian (= placental) mammals tends towards prolonged intrauterine development and short lactation has been interpreted as an evolutionary advance over the metatherian (= marsupial) short gestation and prolonged lactation. However, it has recently been postulated that marsupial reproduction involves low initial energy investment and may be advantageous by minimizing energy loss if conditions necessitate early termination. Moreover, because marsupials have basal metabolic rates (BMRs) 30% lower than those of most eutherians, it has been suggested that daily and total energy expenditures during reproduction may also be lower. We have now tested the predictions that low BMR is maintained during reproduction and that initial investment is lower in marsupials. Using indirect calorimetry, we have made the first longitudinal measurements of energy expenditure during reproduction for a marsupial and for two eutherian species with low BMRs. We find that initial investment is lowest in a eutherian and total energetic expenditures were greatest for the marsupial. We also find that, relative to BMR, all three species have increased mean maternal resting metabolic rates (RMRs) during both gestation and lactation; this is the first evidence that mammals with low BMRs can substantially elevate metabolism for prolonged periods during gestation and lactation.     

灰团网菌的生活史

采用基物培养、燕麦-琼脂培养技术及扫描电镜技术对灰团网菌的个体发育过程进行了研究,在燕麦琼脂培养基上完成了从孢子到孢子的生活史.结果表明:灰团网菌生活史包括单核的黏变形体或游动胞、多核的营养体原质团以及孢子形成阶段.孢子球形,表面具疣突;孢子萌发为孔式,一个孢子可释放一个黏变形体.黏变形体常行变形运动,在有水的条件下,可转变为游动胞并具有游动的特性.合子形成原质团.成熟原质团白色,类型为显型,具有扇形网络状菌脉.琼脂培养基上获得的灰团网菌孢子与野生型相似,并具有可育性.     

疟疾的两种带菌体之间的竞争对其共存的影响

在能够传染疟疾病的蚊子中引入对此病原体有抵抗力的蚊子,基于随机配对法则和一个描述竞争的死亡率矩阵,建立起疟疾传染过程的数学模型．在假设两种蚊子能够共存的情况下,证明了此模型的两个无病平衡点的稳定性,同时发现蚊子之间的竞争并不会影响两平衡点所对应基本再生率的大小关系,进一步找出了这两种蚊子的共存条件和共存状态的稳定条件．     

两大部类再生产数学模型研究

本文根据马克思的社会再生产理论建立了由物质平衡方程和价值平衡方程组成的数学模型,文中对该模型的性质进行了初步分析。     

Genetic segregation and the maintenance of sexual reproduction

Sexual reproduction confronts evolutionary biology with a paradox: other things being equal, an asexual (all-female) population will have twice the reproductive potential of a competing sexual population and therefore should rapidly drive the sexual population to extinction. Thus, the persistence of sexual reproduction in most life forms implies a compensatory advantage to sexual reproduction. Work on this problem has emphasized the evolutionary advantages produced by the genetic recombination that accompanies sexual reproduction. Here we show that genetic segregation produces an advantage to sexual reproduction even in the absence of an advantage from recombination. Segregation in a diploid sexual population allows selection to carry a single advantageous mutation to a homozygous state, whereas two separate mutations are required in a parthenogenetic population. The complete fixation of advantageous mutations is thus delayed in a heterozygous state in asexual populations. Calculation of the selective load incurred suggests that it may offset the intrinsic twofold reproductive advantage of asexual reproduction and maintain sexual reproduction in diploid populations.     

仙湖3号瘦肉型鸭的选育进展

本文以仙湖2号鸭为选育材料,采用家系选择和个体选择相结合的方法,通过两代选育,种鸭的繁殖性能和肉鸭的生长速度、饲料转化率及胸腿肌率较原有种群有显著提高,部分性状已达到或超过育种目标,选育效果显著.     

点光源菲涅耳二元全息图再现像质的分析

对点光源菲涅耳二元全息图再现像进行了量化分析，同正弦菲涅耳全息图再现像比较，二元全息再现时除了背景噪声增大及出现高级次的像以外，像质基本不变并提高了衍射效率．这一结果为计算机制全息的实际应用开辟了一条新的思路．     

孢子植物的生活史

孢子植物的生活史可归纲为七种类型:(1)只有营养繁殖;(2)只有无性生殖;(3)只有单相植物体进行有性生殖;(4)只有双相植物体进行有性生殖;(5)只有单相植物体进行无性和有性生殖;(6)生活史中出现两种核相的两种植物体;(7)生活史中出现两种核相的三种植物体,后两种均具有世代交替现象。     

论教育再生产——教育功能的社会学审视

人们通常认为教育的主要功能是传递文化.其实,这仅仅看到了教育的表面功能,而没有看到教育的深层功能.教育其实还具有再生产的功能."再生产"指的是学校知识直接有助于现存经济和政治结构的意识形态,实践和特权制度的合法化与永久性的某些特点.教育再生产主要包括教育的社会再生产和教育的文化再生产两大类.占统治地位的阶层通过利用手中的职权,将符合自己阶层需要和利益的知识筛选进学校的教育体系中,并对筛选出来的知识加以分层和组织,同时利用考试等评价手段来引导学生的价值观及其发展,以实现其最大程度的控制.     

猬实小孢子发生及雄配子体发育研究

研究猬实小孢子发生及其雄配子体发育的特征。其花药壁的发育属双子叶型，小孢子母细胞减数分裂为同时型，四分体主要为四面体型，成熟花粉为三细胞型，具三萌发孔。绒毡层为变形绒毡层，花粉成熟时药室内壁有条状加厚。     

新疆石河子市大学生性与生殖健康教育干预研究

探讨与评价对大学生进行性与生殖健康教育的模式、内容和效果。采用前瞻性干预研究的方法,对石河子大学2000级2700名新生进行为期两年多的性健康知识教育。对干预研究的可行性和效果进行科学的评价。通过教育,项目学生的性与生殖健康的知识、态度、观念和行为有了明显的提高和转变,总的回答正确率由干预前的48．32％上升到71．06％,提高了22．74个百分点。大学生的性与生殖健康教育是必要的,项目教育的内容和采用的专题讲座、同伴教育、主题班会和咨询服务等方式方法是可行的、有效的,也是受学生欢迎的。     

浙江天童不同生境和攀援方式对葛藤有性生殖特征的影响初探

通过对葛藤在2种生境条件及2种攀援方式下,每个花序的平均开花数量、座果数量、种子数、单果平均干重以及座果率等有性生殖特征的数量化比较分析,探讨了不同的生境条件和攀援方式对葛藤的有性生殖特征的影响,结果表明：1）各样地葛藤种群所处立地资源差异,导致各种群在有性生殖特征（开花数量、座果数量、种子数量及座果率）的数量特征方面差异显著,尤其是生长在阳生、水分充裕的生境条件下,为攀援植物体的种群与生活在荫生环境、为匍匐植物体的种群之间差异最为显著。与荫生、无支持木的种群相比,阳生而且攀援的种群的座果率是其40倍之多,平均座果数量是其53倍,平均种子数量是其70倍,平均开花数量比它高30％;2）当攀援方式作为主导因子时,葛藤生殖特征所产生的差异更显著于生境条件作为主导因子时的差异;3）对有性生殖特征进行相关性分析．葛藤的座果率与开花数量负相关、与座果数量正相关;单果序的座果数量与种子数量和开花数量呈正相关关系。     

Evolution of plant reproduction: From fusion and dispersal to interaction and communication

Based on the existing data concerning the evolution of the sexual reproduction, it is argued that the processes of sex differentiation and interactions play a key role in evolution. From the beginning environment and organism are unified. In a changing dynamic environment life originates and the interaction between life and environment develops from simple to more complex organisms. Sexual reproduction is introduced after the origin of meiosis and is a key process in evolution. The asexual reproduction process prepares to dispersal. Sexual reproduction process adds the genome renewal and the gamete-gamete interaction. Reproduction and dispersal are connected and the process of reproduction has similarities between asexual and sexual reproduction. Unicellular algae develop the physiological and morphological sex differentiation. Sex differentiation is connected with the way of dispersal. The step to multicellular plants introduces cell isolation after meiosis and by the stay on the mother plant within a cell or organ, plant-cell apoplastic interaction originates and by prolonged stay the plant-plant interaction. This stay influences the type of dispersal. A life cycle with alternation of generations and two moments of dispersal permits plants to go on land. In ferns a shift in the moment of sex differentiation to meiospore happens and the stay of the macrospore leads to the seed plants. In water all types of sexual reproduction, interactions and the alternation of generations are prepared and these are used to conquest land. On land the biotic dispersal is realized. The phylogeny of sexual reproduction reveals that the sex differentiation and interaction are the main causes in the evolution of sexual reproduction. Sexual reproduction shows interactions during gamete fusion, between organism and environment and in multicellular plants between organisms. With respect to other types of interaction as in symbiosis or the nutrient chain, interaction is considered as an important action which is based on a persisting cooperation and points to a push during evolution. The push is expressed as communication： the driving force in the evolution. Based on the interactions between organisms and interactions between organisms and the dynamic environment, communication is considered as a driving force leading to the evolution as explained in the development of plant reproduction. Consequences for reproduction, its regulation and the process of evolution are discussed.     

基于分数富立叶变换的非涅尔全息存储

本文分析了非涅尔全息存储与再现的一些性质,论证了它们和分数富立叶变换之间可以互相变换.提出了用二个罗曼I型的分数富立叶变换光学系统来实现非涅尔全息存储及再现.     

Progress in studies of fish reproductive development regulation

Mechanisms of the animal reproductive development are an important research field in life sciences.The study of the reproductive development and regulatory mechanisms in fishes is important for elucidating the mechanisms of animal reproduction.This paper summarizes recent advances in the mechanisms of fish sex determination and differentiation,of fish gonad development and maturation,and of fish germ cell development,as well as the according regulating strategies.Fishes comprise an evolutionary stage that links invertebrates and higher vertebrates.They include diversiform species,and almost all vertebrate types of reproduction have been found in fishes.All these will lead to important advances in the regulatory mechanisms of animal reproduction by using fishes as model organisms.It will also enable novel fish breeding techniques when new controllable on-off strategies of reproduction and/or sex in fishes have been developed.     

2种浮游硅藻对底栖桡足类日本虎斑猛水蚤存活、发育和繁殖的影响

运用实验生态的研究方法,研究了2种浮游硅藻对底栖桡足类日本虎斑猛水蚤(Tigriopus japonicus)不同发育阶段的存活率、发育时间以及成体持续产幼数的影响.结果表明:日本虎斑猛水蚤可以直接有效地利用这2种浮游硅藻并完成其整个世代的发育和成体的繁殖,但是不同藻类对该种猛水蚤的影响不同.总体来说,牟氏角毛藻(Chaetocerosmuelleri)是日本虎斑猛水蚤整个发育阶段以及成体繁殖期间良好的饵料;低浓度(含碳量0.03μg/mL)的中肋骨条藻(Skeletonema costatum)也是日本虎斑猛水蚤成体繁殖期间的良好饵料,但该藻在较高浓度(含碳量≥0.17μg/mL)下虽然对日本虎斑猛水蚤的存活无抑制作用,对其发育和繁殖却均产生抑制.此外,与牟氏角毛藻相比,投喂相同高浓度(含碳量8.50μg/mL)的中肋骨条藻后,日本虎斑猛水蚤的各期发育时间延长、持续产幼数降低,差异显著(p<0.05).     

Social parasitism by male-producing reproductive workers in a eusocial insect

The evolution of extreme cooperation, as found in eusocial insects (those with a worker caste), is potentially undermined by selfish reproduction among group members. In some eusocial Hymenoptera (ants, bees and wasps), workers can produce male offspring from unfertilized eggs. Kin selection theory predicts levels of worker reproduction as a function of the relatedness structure of the workers' natal colony and the colony-level costs of worker reproduction. However, the theory has been only partially successful in explaining levels of worker reproduction. Here we show that workers of a eusocial bumble bee (Bombus terrestris) enter unrelated, conspecific colonies in which they then produce adult male offspring, and that such socially parasitic workers reproduce earlier and are significantly more reproductive and aggressive than resident workers that reproduce within their own colonies. Explaining levels of worker reproduction, and hence the potential of worker selfishness to undermine the evolution of cooperation, will therefore require more than simply a consideration of the kin-selected interests of resident workers. It will also require knowledge of the full set of reproductive options available to workers, including intraspecific social parasitism.     

文化社会学视野下的高校图书馆文化建设

图书馆文化建设的思想与实践作为目前研究热点之一,多从静态的文化观入手。静态的文化观掩盖了图书馆文化建设的社会再生产功能。从文化社会学视角观察,高校图书馆文化建设应该从学术性和自主性两方面入手,以适应其作为社会再生产机构的占位。     

松嫩平原两种群落虎尾草种群有性繁殖的比较

通过调查与测定,分析了松嫩平原两种群落虎尾草种群有性繁殖的特点。结果表明,虎尾草种群的有性繁殖力较强,羊草＋虎尾草群落中虎尾草的生殖株、穗和果实的生长发育均受到种间竞争的制约,籽实生产量明显低于虎尾草群落;不同群落的虎尾草种群生物量分配规律相似,均将较多能量分配给生殖生长,产生大量种子,体现了一年生植物尽可艰保留大量后代这一繁殖策略。     

贵州兴义中三叠世胡氏贵州龙形态特征及生殖方式初探

通过对两件胡氏贵州龙标本进行详细的形态学描述和解剖学对比, 确认标本中所有个体均具有颞孔小、眼孔大、肋骨粗肿、尺骨异常宽阔等典型特征, 并对胡氏贵州龙的形态特征进行了补充。通过骨块测量数据, 可鉴定出3个成年个体的性别和1个幼体的个体发育阶段。结合古地理和胚胎保存信息, 认为胡氏贵州龙的生殖方式可能是胎生, 但尚不能完全排除卵胎生的可能性。