吗啡对猕猴瞳孔光反应能力的影响

光照能明显改变正常人和动物瞳孔的大小,而精神疾病及药物滥用则影响人和动物瞳孔对光的反应性.因此,瞳孔对光反应异常可以用作检测精神疾病和药物滥用的指标.有关药物滥用是如何影响瞳孔对光的反应性的研究还很少.为定量地测量成瘾性药物对瞳孔光反应变化的影响,该文采用猕猴为实验对象,通过在黑暗环境中测量猕猴在吗啡给予前和吗啡给予后的不同时间段,其瞳孔直径大小以及其对光反应能力的变化情况,来系统研究吗啡是如何影响这种非自主性反射系统的.研究发现,吗啡给予降低了猕猴在黑暗环境中的扩瞳反应,并且降低了瞳孔对光反应的收缩率.该文为将瞳孔对光反应特征用作鉴定吸毒者的检测手段提供了实验依据.     

信息加工理论对生物教学的启示

生物学知识和技能的获得,以及生物学能力的形成,都是以信息加工理论的记忆为基础。认知心理学的信息加工理论作为一种学习理论,对我们从事生物学教学有着直接或潜在的指导作用。     

慈竹母株大小对克隆生长的影响

 克隆生长在慈竹种群更新中占有重要地位。本文以基径和生物量两个指标同时衡量慈竹(Neosinocalamus affinis)的母株大小,并分析了母株大小对新竹笋产生、竹笋大小和根茎大小的影响。结果表明：1）慈竹的成竹基径与一级母株基径、二级母株基径以及与2龄和3龄母株平均单株生物量呈正相关,但是成竹基径随一级母株基径增加比随二级母株基径增加而增加的速率快得多;2）慈竹母株大小与各样方中出笋数、活笋数和死笋数无显著的正相关;3）发笋母株的基径显著大于未发笋母株,但发一个笋母株与发两个以上笋母株的基径无显著差异;4）母株基径、2龄和3龄母株平均单株生物量都与根茎的长度和粗度呈显著正相关,且竹笋基径与根茎粗度也呈显著的正相关。母株大小对慈竹竹笋的影响是通过影响根茎实现的。总之,慈竹的克隆生长在个体水平受母株大小制约。     

用于研究快速扫视对瞳孔光反射调制作用的新方法

瞳孔对光反射系统和快速扫视系统在解剖学和功能上都有着紧密的联系,但是快速扫视系统对瞳孔的光反射系统是否有调制作用尚无报道。研究这两个系统间的调制作用,必须了解光刺激不均匀和近反应对瞳孔直径变化是否有影响。该研究以人为被试,设计了一种全新的实验方法,研究光刺激不均匀和近反应对瞳孔直径变化的影响。实验方法：将被试的一只眼用密闭的眼罩罩住给予脉冲光刺激,刺激由位于眼罩内全视野范围水平排列的一排发光二极管(light emitting diodes,LEDs)给出,被试的另一只眼用来记录眼动和瞳孔直径的变化,研究水平方向的快速扫视对瞳孔对光反射时瞳孔直径变化的影响。实验结果：比较被试注视视野内不同位置的瞳孔对光反射相对收缩率无显著差异（P=0.148, 非配对样本t检验）。结论：本方法消除了光刺激不均匀和近反应对瞳孔直径变化的影响,可用于研究快速扫视系统对瞳孔光反射系统间的调制作用。     

群体大小对青幼鱼群体特征的影响

为考察群体大小对青幼鱼(Mylopharyngodon piceus)群体特征的影响,在(25±0.5)℃条件下对1、2、4和8尾青幼鱼组成的群体(N=12)进行视频拍摄和轨迹分析,得到游泳速度和空间分布特征数据,实验同时测定了不同群体大小对恐吓刺激的反应差异。结果显示:青幼鱼自发游泳速度多处于0—10 cm/s,不受群体大小的影响,但不同个体速度同步性随群体大小增加而显著下降;青幼鱼最近邻距离多数位于0—10 cm,且随着群体大小增加,最近邻距离和群体排列的极性均随群体数量上升而显著下降;青幼鱼群体中位置分布具有个体差异,且随着群体数量上升差异加剧;青幼鱼对恐吓刺激的反应率不受群体大小的影响,但群体内部不同个体对刺激的反应的一致性随群体大小上升有所下降。结果表明:青幼鱼具备集群性,在2—8个体范围内随群体大小上升凝聚力上升,协调性下降;群体特征的改变对恐吓刺激反应率没有显著影响,但协调性的下降导致反应一致性降低;青幼鱼群体中不同个体在集群活动中可能存在社会分工,且这种分工的作用在大群体大小上升表现更为明显。     

呼伦贝尔草原植物叶片大小与数量的权衡关系及其内在机制

叶片大小与数量的权衡关系是植物生长策略的基础,研究叶片大小与数量权衡关系的内在机制对于深刻理解植物生长策略具有重要意义.本研究以单个叶片干重表示叶大小,以单位茎上的叶片数量表示出叶强度,采用标准主轴回归分析方法研究呼伦贝尔草原植物叶片大小与数量的权衡关系以及内在机制.结果表明:陈旗嵯岗(典型草原)和陈旗八一(草甸草原)...     

花器官大小调控机制的研究进展

自然界中植物花的大小受到遗传因素和环境因素的双重调节。传粉者、天敌和逆境胁迫等多种因素相互制约,作为选择压力共同影响花器官形态和繁殖能力,通过选择适合的基因型,推动花器官大小的进化。近年来,对花器官大小调控机制的研究又有新的进展,已在模式植物拟南芥中分离出大量参与花器官大小调控的基因,并证实它们主要在细胞水平影响花器官的增殖和生长。本文介绍花器官大小的进化及其生物学意义,并综述了拟南芥花器官大小调控机制的研究进展。     

急诊中瞳孔检查对昏迷及休克患者病程判断的重要性分析

目的:分析急诊中瞳孔检查对昏迷及休克患者病程判断的重要性。方法:对所有患者进行相关体格检查、实验室检查以及神经系统的检查,将患者按不同的病因类型分为两组,观察按病因分类后患者的瞳孔情况,包括患者是否发生瞳孔散大或缩小,双侧瞳孔是否等大及瞳孔是否发生对光反射消失。结果:148例患者中属于结构性昏迷或休克的患者68例,代谢性昏迷或休克80例,结构性昏迷或休克组患者的瞳孔不等大例数大于代谢性昏迷或休克组,结构性昏迷或休克组患者的瞳孔对光反射消失的例数大于代谢性昏迷或休克组。结论:对患者瞳孔合理科学的检查是急诊中判断患者病因情况的重要方法,对了解患者的病情和及时的救治具有积极意义。     

施肥与品种及其种子大小对冬小麦光合及叶绿素荧光特性的影响

以土垫旱耕人为土为供试土样,采用4个冬小麦品种、3种播种方式和4种施肥方式进行盆栽试验,研究施肥、品种和种子大小对小麦叶片光合和叶绿素荧光特性的影响.结果表明:(1)在开花期和灌浆期,旗叶叶绿素相对含量(SPAD值)均为NP配施最高,其平均值分别比对照显著增加17.83%和13.01%;NP配施条件下,在开花期和灌浆期SPAD均为大粒单播较高并显著高于小粒单播;开花期和灌浆期SPAD分别以远丰998和咸农39最高并显著高于其它品种,平均比最低的白芒麦分别高17.68%和18.75%.(2)对旗叶净光合速率来说,开花期的NP配施处理比对照略有下降,而单施N和P分别比对照显著降低13.03%和23.17%,灌浆期的平均值以NP配施最高且比对照显著提高6.95%;小偃6号在开花期显著高于其余品种4.01%~6.19%(P<0.05),而白芒麦和咸农39则在灌浆期具有较明显优势,均分别显著高于其余品种约16.60%~26.91%;在开花期和灌浆期,2种单播方式平均值相近且显著高于混播方式.(3)就叶片Fv/Fm和Fv/Fo值而言,NP配施明显高于其它施肥处理,且NP均衡供应时远丰998和混播方式具有明显优势.可见,氮磷配施有利于提高各品种SPAD值、Pn以及叶片Fv/Fm和Fv/Fo比值,能有效改善植株的光合特性;施肥与品种、施肥与播种方式以及播种方式与品种存在显著交互作用,宜因种施肥.     

南非Hluhluwe-Umfolozi公园植被对非洲狮群大小的影响

非洲狮(Pantheraleo)群处于不断的分裂-聚合过程,其亚群大小与原狮群大小以及诸如狮群捕食成功度、协作幼仔保护及狮群领域防卫等社会性因素有关。我们分析了南非一个保护区(Hluhluwe-Umfolozi公园)15年间的狮群大小,其成年雌狮和成年雄狮群的大小在保护区内呈显著性变化。在开放生境中雌狮结大群,而茂密植被生境中则结小群。雄狮群大小与植被类型无关,但在大的雌狮群分布区域发现大雄狮群。令人惊奇的是,作为幼狮成活率指标的幼狮群大小和雌狮平均幼仔数在保护区内没有显著性差异。我们认为,雌狮群大小的不同是对植被结构的适应,即在开放生境中大群有利于协作狩猎、育幼、共同保护幼仔、应对高强度群间领域防卫竞争。相反,茂密植被中,群间竞争很低,高密度植被覆盖有利于狩猎成功及补偿小狮群对幼仔保护的不足。雌狮平均幼仔数在整个保护区内没有变化,我们认为是由于开放生境和茂密植被对狮群大小起到相似的调节作用     

When to use social information: the advantage of large group size in individual decision making

Correct decision making is crucial for animals to maximize foraging success and minimize predation risk. Group-living animals can make such decisions by using their own personal information or by pooling information with other group members (i.e. social information). Here, we investigate how individuals might best balance their use of personal and social information. We use a simple modelling approach in which individual decisions based upon social information are more likely to be correct when more individuals are involved and their personal information is more accurate. Our model predicts that when the personal information of group members is poor (accurate less than half the time), individuals should avoid pooling information. In contrast, when personal information is reliable (accurate at least half the time), individuals should use personal information less often and social information more often, and this effect should grow stronger in larger groups. One implication of this pattern is that social information allows less well-informed members of large groups to reach a correct decision with the same probability as more well-informed members of small groups. Thus, animals in larger groups may be able to minimize the costs of collecting personal information without impairing their ability to make correct decisions.     

Can emotion recognition be taught to children with autism spectrum conditions?

Children with autism spectrum conditions (ASC) have major difficulties in recognizing and responding to emotional and mental states in others'' facial expressions. Such difficulties in empathy underlie their social-communication difficulties that form a core of the diagnosis. In this paper we ask whether aspects of empathy can be taught to young children with ASC. We review a study that evaluated The Transporters, an animated series designed to enhance emotion comprehension in children with ASC. Children with ASC (4–7 years old) watched The Transporters every day for four weeks. Participants were tested before and after intervention on emotional vocabulary and emotion recognition at three levels of generalization. The intervention group improved significantly more than a clinical control group on all task levels, performing comparably to typical controls at time 2. The discussion centres on how vehicles as mechanical systems may be one key reason why The Transporters caused the improved understanding and recognition of emotions in children with ASC. The implications for the design of autism-friendly interventions are also explored.     

Social facilitation of insect reproduction with motor-driven tactile stimuli

Tactile stimuli provide animals with important information about the environment, including physical features such as obstacles, and biologically relevant cues related to food, mates, hosts and predators. The antennae, the principal sensory organs of insects, house an array of sensory receptors for olfaction, gustation, audition, nociception, balance, stability, graviception, static electric fields, and thermo-, hygro- and mechanoreception. The antennae, being the anteriormost sensory appendages, play a prominent role in social interactions with conspecifics that involve primarily chemosensory and tactile stimuli. In the German cockroach (Blattella germanica) antennal contact during social interactions modulates brain-regulated juvenile hormone production, ultimately accelerating the reproductive rate in females. The primary sensory modality mediating this social facilitation of reproduction is antennal mechanoreception. We investigated the key elements, or stimulus features, of antennal contact that socially facilitate reproduction in B. germanica females. Using motor-driven antenna mimics, we assessed the physiological responses of females to artificial tactile stimulation. Our results indicate that tactile stimulation with artificial materials, some deviating significantly from the native antennal morphology, can facilitate female reproduction. However, none of the artificial stimuli matched the effects of social interactions with a conspecific female.     

Effects of social group size on information transfer and task allocation

Summary Social animals exchange information during social interaction. The rate of interaction and, hence, the rate of information exchange, typically changes with density and density may be affected by the size of the social group. We investigate models in which each individual may be engaged in one of several tasks. For example, the different tasks could represent alternative foraging locations exploited by an ant colony. An individual's decision about which task to pursue depends both on environmental stimuli and on interactions among individuals. We examine how group size affects the allocation of individuals among the various tasks. Analysis of the models shows the following. (1) Simple interactions among individuals with limited ability to process information can lead to group behaviour that closely approximates the predictions of evolutionary optimality models, (2) Because per capita rates of social interaction may increase with group size, larger groups may be more efficient than smaller ones at tracking a changing environment, (3) Group behaviour is determined both by each individual's interaction with environmental stimuli and by social exchange of information. To keep these processes in balance across a range of group sizes, organisms are predicted to regulate per capita rates of social interaction and (4) Stochastic models show, at least in some cases, that the results described here occur even in small groups of approximately ten individuals.     

Ant defence system: A mechanism organizing individual responses into efficient collective behavior

A colony of social insects is an excellent model for investigating the organization of responses of subunits (i.e. colony members) with limited skills into sophisticated collective behavior. The defence system of Lasius niger ant colonies is well organized in a context-dependent way. The proportion of fighting ants to fleeing ants changes gradually according to the importance of the area being defended, and was higher where ants tended honeydew-rich aphids and on trails for foraging with heavy traffic, than where ants were walking alone or on trails with light traffic. Although there were intrinsic differences in aggressiveness between individual ants, the differences in aggressive responses between defended areas was not due to the presence of highly aggressive or timid individuals in each area. Instead, it was due to a change in aggressiveness of individuals in response to external conditions. The cue that altered individual aggressiveness was the presence of surrounding nest-mates, rather than the presence of aphids. We concluded that the defence system of this ant species consists of three processes: (i) a recruiting system that allocates more workers to more valuable resources; (ii) individual ants following a simple decision rule to become more aggressive in response to increased numbers of nest-mates nearby (hence aggressive behavior reflecting the importance of each area to the colony); and (iii) variability in individual responses causing a gradual change in the proportion of fighting ants responding to a threat.     

Importance of learning in the response of ewes to male odor

Exposure of anestrous ewes to a ram or its odor results in the activation of the luteinizing hormone (LH) secretion leading to reinstatement of cyclicity in most females. Sexual experience and learning have been suggested as important factors to explain the variability of the female responses. In experiment 1, we compared the behavioral and endocrine responses of four groups of anestrous females that differed in age (young or adult) and previous exposure to males [naive (no exposure) or experienced (courtship behavior for young and numerous mating for adults)]. Age did not seem to affect the LH response to males or their odor. In contrast, sexual experience was a critical factor: the proportion of females exhibiting an LH response to male odor was significantly higher in experienced than in naive ewes. Sexual experience affected the response to male odor, but did not have an effect on responses to the male himself. A second experiment investigated whether the LH response to male odor could result from an associative learning process. Accordingly, we tested the effectiveness of a conditioned stimulus (lavender odor) previously associated with the male, in inducing the endocrine response. The results indicate that the odor of lavender activated LH secretion only in ewes that have been previously exposed to scented males. This demonstrates that ewes are able to learn the association between a neutral odor and their sexual partner.     

Imbalanced genomic imprinting in brain development: an evolutionary basis for the aetiology of autism

We describe a new hypothesis for the development of autism, that it is driven by imbalances in brain development involving enhanced effects of paternally expressed imprinted genes, deficits of effects from maternally expressed genes, or both. This hypothesis is supported by: (1) the strong genomic-imprinting component to the genetic and developmental mechanisms of autism, Angelman syndrome, Rett syndrome and Turner syndrome; (2) the core behavioural features of autism, such as self-focused behaviour, altered social interactions and language, and enhanced spatial and mechanistic cognition and abilities, and (3) the degree to which relevant brain functions and structures are altered in autism and related disorders. The imprinted brain theory of autism has important implications for understanding the genetic, epigenetic, neurological and cognitive bases of autism, as ultimately due to imbalances in the outcomes of intragenomic conflict between effects of maternally vs. paternally expressed genes.