Conditioned defensive burying in rats: Availability of burying materials

Rats shocked once by a stationary, wire-wrapped prod mounted on the wall of the test chamber incorporated sand, wooden blocks, or commercial bedding material on the floor of the chamber into a defensive response. They moved the available material toward and over the shock prod in all three conditions, adapting the response topography to the particular demands of the available material. In the sand and bedding conditions, the rats buried the prod by pushing and spraying piles of the material with snout and forepaws, whereas, in the blocks condition they picked up the blocks with their teeth and placed them individually around the prod. In Experiment 2, the rats buried the shock prod with blocks even when they had to first carry the blocks to the prod from the back of the chamber. Thus, conditioned defensive burying is not a simple, reflexive response to objects paired with a painful stimulus: it is a complex behavioral sequence that can vary as a function of the availability of burying materials.     

The role of spatial and temporal contiguity in defensive burying in rats

The degree of spatial and temporal contiguity between contact with a prod and shock was varied in three experiments to see how these factors contribute to defensive burying. In Experiment 1, rats shocked once through a grid floor while touching a prod buried the prod just as much as did rats shocked through the prod. Experiment 2 showed that rats either shocked through the floor more than 1 min after touching the prod or shocked in the absence of a prod did not bury the prod. Thus, close temporal contiguity between grid shock and prod contact appears necessary for burying. Nevertheless, grid-shocked rats do learn something different from prod-shocked rats, since they bury the prod less and the walls more than do prod-shocked rats when the position of the prod is changed in the test chamber (Experiment 3).     

Influence of conspecific stress odors and shock controllability on conditioned defensive burying

In Experiment 1, rats received a session of 80 inescapable tail shocks or no shocks while restrained in a tube. During tests of conditioned defensive burying 24 h later, the bedding of the chamber contained odors from either stressed or nonstressed conspecific donor rats. Following a single prod shock, subjects that had had prior shocks or that were tested with the stress odors spent significantly less time burying the prod, made smaller piles of bedding, and displayed more freezing behavior. The combination of prior shock and stress odors during later testing enhanced these effects. In Experiment 2, a yoked group of rats that was given inescapable shocks, in contrast to a group that had wheel-turn escape training and one that was restrained but not shocked, later showed significantly less burying and more freezing when tested for defensive burying with stress odors present. In both experiments the duration of burying and the heights of piles were positively correlated, and both of these measures were negatively correlated with freezing. The demonstrated capacity of unconditioned stress odors to mediate different degrees of fear, depending upon the controllability of prior shock, is related to other studies of learned helplessness, and the predominance of freezing over burying is discussed in terms of various types of defensive strategies, stimulus-control processes, and the author’s stress-coping-fear-defense (SCFD) theory.     

Behavioral field analysis in two strains of rats in a conditioned defensive burying paradigm

Two strains of rats (albino Wistar and hooded PVG/c) were exposed to a conditioned defensive burying paradigm that consisted of placing rats in a test chamber with bedding material on the floor, shocking them with a shock prod, and recording the time each rat spent in burying responses toward the prod. Various behaviors other than burying (freezing, grooming/paw licking) were observed by a time-sampling procedure during the control, conditioning, and extinction sessions, each of which was 15 min in duration. Wistar rats generally showed behavioral inhibition, as evidenced by less burying, lower exploratory and ambulatory behavior, and higher freezing behavior. PVG/c rats spent significantly more time engaged in burying and accumulated more bedding material in the conditioning session than did the Wistar rats. No significant differences between the two strains of rats were observed during the extinction session in terms of these measurements. The results indicate that Wistar rats have a greater tendency to freeze when coping with the noxious stimulus in a conditioned defensive burying paradigm, whereas the dominant coping style for PVG/c rats is defensive burying.     

Influence of conspecific and predatory Stressors and their associated odors on defensive burying and freezing responses

In Experiment 1, male rats were exposed to either aggressive (i.e., alpha) or nonaggressive conspecific colonies and tested 24 h later, with or without alpha odors, for freezing behavior and burying of a wall prod that had been the source of a brief electric shock. The results indicated that prior defeat experience and the presence of alpha odors alone during testing had no significant effects, but the combination of prior defeat and alpha-odor testing significantly decreased burying and increased freezing behavior. In Experiment 2, we examined the effects of noncontact exposure to a cat, as a predatory Stressor, during subsequent prod-shock tests involving the presence or absence of cat odors. Exposure to a cat failed to disrupt later prod burying and did not produce freezing. However, the presence of cat odors during testing significantly reduced the amount of defensive burying,without resulting in an increment in freezing. In Experiment 3, rats were given 1, 5, or 30 inescapable preshocks in the presence of either cat odors or a hedonically neutral citronella odor and were tested 24 h later for prod burying and freezing with or without these odors. Both the cat and the citronella odors resulted in a significant reduction in burying and an increase in freezing for rats given 5 and 30 preshocks and tested in the presence of these respective conditioned odors. For the groups that were given 5 preshocks, preshock and later testing in the presence of cat odors resulted in significantly less prod burying and more freezing than for rats that were preshocked and tested in the presence of citronella. The findings of these three ethoexperimental studies are discussed in terms of the learned-helplessness theory, the stress-coping-fear-defense (SCFD) theory, and the concept of selective CS-US associability.     

云计算环境下典型安全威胁分析及防御策略研究

深入分析了云计算环境下的各种典型安全威胁,有针对地提出了保障云安全的防御策略,保护云计算基础架构,提供可信云、安全云服务,建立新的安全防护模式,加强云计算的终端防御,获得全面的安全防护。     

Subitizing, magnitude representation, and magnitude retrieval in deaf and hearing adults

This study examines basic number processing (subitizing, automaticity, and magnitude representation) as the possible underpinning of mathematical difficulties often evidenced in deaf adults. Hearing and deaf participants completed tasks to assess the automaticity with which magnitude information was activated and retrieved from long-term memory (using a Stroop-like paradigm to assess congruity effects), the representational format of magnitude information (by analysis of distance and Spatial Numerical Association of Response Codes effects), and the ability to rapidly enumerate small sets (subitizing). Both groups showed distance effects taken to indicate the use of a visual-spatial analog number line representing approximate quantity. Furthermore, both groups showed similar patterns of performance on the subitizing tasks and showed similar amounts of interference in an analysis of congruity effects. This is taken as evidence against the notion that idiosyncratic differences in basic number processing account for mathematical difficulties experienced by deaf individuals.     

The effects of physical environment,time in captivity,and defensive distance on tonic immobility,freezing, and flight behaviors inAnolis carolinensis

The effects of physical environment, time in captivity, and distance between potential predator and prey on defensive behaviors were examined inAnolis carolinensis. When the experimenter was nearby, duration of immobility was significantly longer in the open than in areas with nearby foliage. However, this relationship between duration of immobility and the testing environment in the anole was reversed by Day 9 in captivity. Flight latency of anoles after termination of immobility was significantly shorter in anoles housed in terraria containing foliage, while greater incidence of freezing was shown by anoles housed in empty terraria. These results suggest that although the physical environment has strong effects on defense behaviors, the different defensive reactions are influenced in different ways.     

毛泽东与高考的革废

高考作为我国核心的教育制度之一,关乎社会的方方面面,牵涉到个体与家庭的利益。然而,文化大革命初期全国统一高考即被废除,与毛泽东的阶级观、实践观、教育目的观、考试观有一定的联系。从现有的文献资料来看,毛泽东并没有明确指示或者主张废除高考,其考试思想至今仍闪烁着智慧的光芒。     

清代武科举废除的历史反思与借鉴

武科举作为科举考试中仅次于进士科的重要科目,自唐创立以来,延续一千二百余年,对中国封建社会产生了不可估量的作用,选拔出了一大批治国安邦的武备人才。清代武科举集历代之大成,得人之广、影响之大均超过之前各个朝代。而进入近代以来,生命力顽强的武科举却在短短数十年内从历史的顶峰彻底跌入被永远废止的谷底。系统分析清代晚期武科举的变革历程,对当今军事人才选拔制度有借鉴和启示作用。     

The abolition of secondary school fees in Kenya: Responses by the poor

Following the 2007 presidential election, the Government of Kenya abolished secondary school fees in 2008. In the context of this significant change in policy, this study examines the effect of fees on transition to secondary schooling by following 109 primary school leavers in rural Kenya after the fee abolition, starting in 2007. The study draws on survey data with multiple interviews and finds that the abolition of school fees had limited effects on children from low-income families. The study concludes that although there is a high demand for secondary education in general, whether primary school leavers from low-income families actually enrol in fee-free secondary education depends largely on other direct costs and opportunity costs and their perceived economic returns from such education.     

天体物理中的星等概念比较

通过讨论天体物理中光度,亮度和照度之间的差别,引入星等概念.对包含视星等和绝对星等的关系式进行细化推论,明确了视星等和绝对星等之间的差异以及在天体物理中的重要联系,随后举例介绍了天体物理中的超新星爆发现象.最后归纳出几条重要结论.     

Gypsy children,space, and the school environment

This article draws on data generated from a 3½‐year ethnographic study of the interface between Gypsy culture and the educational system in England. The evidence suggests that Gypsy children have distinctive spatial orientations that are embedded in their own culture and life experience. These relate to issues revolving around degrees of nomadic and sedentary lifestyles, and also around spatial awareness deriving from the site environment. In combination, these features have the potential to make the transition between home and school problematic. Moreover, the utilization of space by Gypsy children is often misinterpreted within schools, being at odds with, and constituting a challenge to, the structured social space of the school environment. In view of the multiple meanings of space, this raises issues about the lack of flexible responses in institutional contexts.     

篮球比赛中防守假动作运用的研究

通过对篮球比赛中防守假动作的运用进行系统分析和研究,认为篮球比赛不仅仅是身体、技术和战术的比拼,还是队员之间临场发挥的智慧较量.比赛中在充分利用身体和技术动作的同时,要聪明合理地运用假动作,做到真真假假、虚虚实实.应将假动作同时运用于进攻和防守之中,获得比赛的主动权.     

Breaking the cycle of office referrals and suspensions: defensive management

This paper focuses on a strategy—Defensive Management—designed to assist teachers to better manage non‐compliance and defiance in the classroom, with the ultimate goal of reducing disciplinary referrals and flow‐on suspensions and exclusions from school. Non‐compliance and defiance are behaviours that teachers find particularly challenging and, traditionally, teachers have responded provocatively and often unsuccessfully when faced with instances of such behaviour. Drawing on an analogy with Defensive Driving, two groups of teachers (pre‐service and primary) were introduced to a strategy developed to help them avoid unproductive conflict (collisions) with students and the harm that such encounters typically result in. The findings of an exploratory study on the use of Defensive Management are reported.     

自异混交群体基因型熵中的数学命题

研究自异混交群体的基因型比例的逐代演变规律对确定选种的具体世代有指导意义。本文把这一演变规律归结为几个数学命题,并进行论证。     

一种网络安全两级防御系统的研究与设计

传统的单一防御产品难以构建一个安全的网络防御系统,在参照一些先进的网络安全解决方案的基础上,提出了一种两级防御体系结构模型。在整个防御系统中,设计了在Linux环境下以基于网络的入侵防御系统(NIPS:Network-based Intrusion Prevention System)为第一级入侵防御系统,以主机安全代理为第二级防御系统。两系统都与管理中心保持有密切的通信机制,其中主机安全代理不仅以软件的方式运行在内部网络的各个主机中,也可以安装在远程用户的便携机和托管服务器上。