A comparison between the bicycle ergometer and the step-test for determining maximum oxygen intake on Kalahari Bushmen

Summary In March 1967 a group of scientists visited the Kalahari desert in Botswana and determined the maximum oxygen capacities of a number of Bushmen subjects by making use of the bicycle ergometer and the step-test.The mean maximum oxygen intake values obtained with the step-test were close to those determined from sub-maximum bicycle ergometer tests, 40.5 and 39.8 ml/(min · kg) respectively. Primitive people can be trained to give good submaximal results on a bicycle ergometer, but it was impossible to obtain reliable maximum work rates for these people on a bicycle ergometer.     

Classical conditioning,sensitization and habituation in the spinal cat

Changes in the flexion reflex of the tibialis anterior muscle of acute spinal cats were examined during conditioning, sensitization and habituation paradigms. Experimental animals were classically conditioned by pairing electrical stimulation of the saphenous nerve (CS) with stimulation of the superficial peroneal nerve (US). Recordings from these nerves assured known and constant stimulus inputs. The response observed was an increase in the magnitude of the reflex response to the CS over training. Habituation (CS only) and sensitization (CS and US presentations, unpaired) control animals exhibited no such reflex facilitation. The results of post-tetanic potentiation studies indicated that the intertrial intervals used were not a factor in the differences observed between experimental and control groups. The results give positive support to the concept of spinal conditioning and emphasize the potential of this model system for the study of neural correlates of learning.     

The pupil's response to affective pictures: Role of image duration,habituation, and viewing mode

The pupil has been shown to be sensitive to the emotional content of stimuli. We examined this phenomenon by comparing fearful and neutral images carefully matched in the domains of luminance, image contrast, image color, and complexity of content. The pupil was more dilated after viewing affective pictures, and this effect was (a) shown to be independent of the presentation time of the images (from 100–3,000 ms), (b) not diminished by repeated presentations of the images, and (c) not affected by actively naming the emotion of the stimuli in comparison to passive viewing. Our results show that the emotional modulation of the pupil is present over a range of variables that typically vary from study to study (image duration, number of trials, free viewing vs. task), and encourages the use of pupillometry as a measure of emotional processing in populations where alternative techniques may not be appropriate.     

Age, sex and strain comparison of habituation of the startle response in the rat

Habituation and sensitization of the acoustic startle response were studied in young (3 month) and aged (26 month) male and female Fischer 344 rats and in young (3 month) and aged (32 month) male Sprague Dawley rats. Tones were presented on 25 consecutive trials for a session, one session on each of four consecutive days. An air puff stimulus immediately preceded trial 20 on each day to test sensitization. All aged rats demonstrated greater short-term (within session) relative habituation than their younger counterparts. Across sessions, aged male rats of both strains habituated more quickly than younger males. Aged female rats habituated more slowly. Sensitization was more likely to occur in younger rats.     

Autonomic, electroencephalographic, and myogenic activity accompanying startle and its habituation during mid-childhood

This study investigated (a) possible associations of the large individual variation in startle, with accompanying autonomic, central nervous system, and myogenic activities in a habituation paradigm; and (b) the patterns of habituation of these variables. Startle blinks to 40 noise bursts, heart rate, alpha activity, and orbicularis oculi electromyographic (EMG) activity preceding and following each startle response were measured in 40 normal 7–11-year-old boys. Statle amplitude and its habituation were independent of association with either initial values or successive changes in the autonomic, alpha, and EMG activities; whereas startle habituated, pre-and poststartle myogenic, alpha, and cardiac activities failed to habituate. Tonic cardiac activity was facilitated, suggesting sensitization of state, as proposed in the dual-process theory of habituation.     

留守儿童的学习适应性及其与学习策略、学习自我效能的关系

目的探讨留守儿童学习适应性的特点,以及学习策略在留守儿童学习自我效能对学习适应性影响中的作用。方法采用测量法,测查264名留守儿童学习适应性、学习自我效能和学习策略。结果①留守儿童学习适应性总体情况较差(χ2=52.428,P<0.001);学习环境是影响留守儿童学习适应性的最突出问题;②学习策略在学习自我效能对学习适应的影响中起中介作用(β=0.59～0.11,t=1.37,P>0.05),进一步研究发现学习策略中的元认知策略和目标管理规划策略对学习适应起到中介作用。结论留守儿童总体学习适应不良;学习策略的教育干预可以有效改善留守儿童的学习适应状况。     

Shock-stress,gastric secretion and habituation in the chronic gastric fistula rat

Unrestrained rats exposed to shock-stress showed an abrupt reduction in both the volume and acidity of gastric secretions, followed by a rapid poststress recovery. The gastric response pattern did not distinguish between rats receiving avoidable or unavoidable shock. Marked habituation of the acid inhibition response occurred within 4 stress sessions.     

Development of mouse activity, stimulus reactivity, habituation, and response to amphetamine and scopolamine

Twenty-four litters of non-inbred Swiss-derived mice were used to study the development of locomotion and tendency to approach a novel object in an open field, as well as the effects of dl-amphetamine sulfate and scopolamine hydrochloride (1 or 2 mg/kg IP). Brief (7 min) tests repeated for three consecutive days were preferred in order to obtain information on between-session habituation. Animals tested on days 14-16 showed low levels of activity without changes in successive sessions. In contrast, an adult-like pattern with a high initial activity and marked between-session decrements prevailed on days 21-23 and 28-30. Dl-amphetamine elevated activity only on days 14-16, while scopolamine produced hyperactivity and impaired habituation only on days 21-23 and 28-30. Latency to approach a novel object by untreated animals showed a substantial reduction between the end of the second week and subsequent developmental stages. This went hand in hand with an appearance of latency increases after dl-amphetamine treatments, while an opposite trend in the scopolamine data failed to reach statistical significance. Activity tests in a photocell apparatus at 61-72 days (without prior treatment) showed a reduction of locomotion relative to the level measured in animals from other litters raised in parallel and not subjected to early testing. Overall, the present data and those of the literature indicate that some developmental phenomena in small rodents are relatively insensitive to a variety of organismic, environmental, and test factors, while others (e.g., inverted U-shaped activity trends and successive modifications of the amphetamine profile) depend on complex interactions between several variables.     

Selected biochemical parameters of two sizes of rat skeletal and heart muscle mitochondria at selected intervals of a 16-week endurance training program

Summary Increases in oxidative capacity of skeletal muscle which has undergone training is well documented. The concomitant shifts in mitochondrial size and cytochrome content have varied with different investigations. In this study the shifts in oxidative capacity, SDH activity, thiolase activity, was measured in two sizes of heart and skeletal muscle mitochondria of rats undergoing 4, 8, and 16 weeks of training. In addition cytochrome content was measured in both sizes of mitochondria of the skeletal muscle. The small mitochondria of skeletal muscle showed the significant gains in number during the first 8 weeks of training while the large mitochondria increased in number during the last 8 weeks of training. The oxygen consumption, SDH activity, thiolase activity and cytochrome content all showed varying peaks in activity and content in the different sizes of mitochondria over the 16 weeks of training. In evaluating training regimes' effects on skeletal muscle it appears important to take into consideration the shifts in size of mitochondria as well as oxidative capacity and enzymatic activity alterations. There were no alterations observed in mitochondrial size in cardiac tissue.     

Age, sex and strain differences in activity and habituation in SHR and WKY rats

The highly inbred strain of Wistar-Kyoto spontaneously hypertensive rat (SHR) and its normotensive, genetic control (WKY) were examined with respect to strain differences in spontaneous activity scores in a novel environment (small activity cage) and in ability to habituate to that environment. These behaviors were examined in experimentally naive rats, 197 SHR and WKY, males and females, at varying ages from 4 to 56 weeks, in order to determine whether there are sex and age differences in addition to the well-known strain differences in these behaviors. Total activity scores, determined in a 15 min test in the activity cage, were higher in SHR than WKY rats; females were significantly more active than males in either strain, and activity scores varied significantly with age both within strains and between strains. Ability to habituate to the test cage was determined by repeating the 15 min activity test at hourly intervals for three additional trials on the same day. The results indicate that the SHR, males and females and at all ages tested, habituate poorly if at all to the test cage as compared with WKY rats. Moreover, despite the variability of baseline activity scores (first trial) observed across ages, sexes and strains, the habituation patterns of either strain remained relatively fixed throughout the first year of life.     

Open-field behavior, habituation and passive avoidance learning: Effect of ACTH and hydrocortisone on Normal and adrenalectomized rats

Exploratory behavior (GMA) and habituation rate (IH) were studied in an open-field situation in normal and adrenalectomized rats. Following this procedure the rats were subjected to passive avoidance learning (PA). Wide-spreading individual differences were observed in the exploratory behavior and the tendency of habituation of normal rats. As compared to the normal values, either the adrenalectomy which was performed 24 hr, 7 days and 28 days prior to the experiments or the ACTH and hydrocortisone treatment failed to modify the GMA and the IH significantly. An improvement of PA was found in the normal rats following ACTH and hydrocortisone treatment. In the adrenalectomized animals the hydrocortisone proved to be effective, whereas ACTH did not influence PA. No correlation was found between GMA, IH versus PA values and the influence of ACTH and hydrocortisone administration on these parameters. It is concluded that the direction of PA is unpredictable on the basis of the open-field test performed on R-Amsterdam strain of rats, and the effect of ACTH on passive avoidance learning is mediated through the adrenal glands.     

The influence of weekly training distance on fractional utilization of maximum aerobic capacity in marathon and ultramarathon runners

Summary This study was designed to examine the interrelationships between performance in endurance running events from 10 to 90 km, training volume 3–5 weeks prior to competition, and the fractional utilization of maximal aerobic capacity (% ) during each of the events. Thirty male subjects underwent horizontal treadmill testing to determine their , and steady-state at specific speeds to allow for calculation of % sustained during competition. Runners were divided into groups of ten according to their weekly training distance (group A trained less than 60 km · week^–1, group B 60 to 100 km · week^–1, and group C more than 100 km · week^–1). Runners training more than 100 km · week^–1 had significantly faster running times (average 19.2%) in all events than did those training less than 100 km · week^–1. or % sustained during competition was not different between groups. The faster running speed of the more trained runners, running at the same % during competition, was due to their superior running economy (19.9%). Thus all of the group differences in running performance could be explained on the basis of their differences in running economy. These findings suggest either that the main effect of training more than 100 km · week^–1 may be to increase running economy, or that runners who train more than 100 km · week^–1 may have inherited superior running economy. The finding that the maximal horizontal running speed reached during the progressive maximal treadmill test was a better predictor (r=0.72) of running performance at all distances than was the (r=0.54) suggests that peak treadmill running speed can predict performance in endurance running events.     

Learning, plasticity, and recovery in the central nervous system

Cerebral functions can be described by the interaction of different brain regions as parts of distributed networks. Learning is seen as a refinement of the connection between the various parts of these networks. Plastic changes, as illustrated in brain charting techniques, are the result of learning (or use) in normal brains or found as adaptation (active or passive) after peripheral or central lesions. The relation between brain reorganization and recovery of function is investigated by two recent studies relating the training-induced improvement of lost function to changes in the brain. Others search for the effects of passive stimulation and drug influences. Independently of the approach, however, the general idea is that recovery can be seen as a reconnection between the remaining parts of the disturbed network. Received: 9 November 1998 / Accepted: 11 March 1999     

Relative effectiveness of galvanic skin response latency, amplitude and duration scores as measures of arousal and habituation in normal and retarded adults

The comparability of latency, duration and amplitude scores of the first derivative of the galvanic skin response (GSR) in normal and retarded young adults was studied under various conditions of stimulus intensity, duration, and repetition. Duration scores were a measure of the onset-to-peak time of the primary wave and were found to be most sensitive to changes in stimulus conditions, least subject to measurement errors, and least cumbersome to handle statistically. Latency scores were found to be least sensitive, with amplitude scores occupying an intermediate position. The correlations between the three types of responses were low and showed no substantial or meaningful differences between stimulus conditions and subject groups. The authors concluded that for some types of GSR measurement, duration scores can replace the more commonly used amplitude scores.     

实习护生学习策略和学习动机及学习成效的质性研究

目的 归纳了解实习护生学习策略和学习动机及学习成效现况,明确三者之间的关系,以提出相应的教育对策,为提高实习效果提供参考。方法 采用质性研究的方法,便利抽取我院20名实习护生、10名带教老师作为访谈对象,对其进行一对一开放式深入访谈。结果 学习动机能通过影响实习护生的学习兴趣、态度、自觉性等方面,间接地影响学习效果;学习策略的深浅对学习动机的影响起着正相关的作用,并对学习成效产生一定的影响。结论 带教老师根据护生已有的学习动机、学习策略状态,使新的学习内容与已有的认知水平构成一个适当的跨度,帮助实习护生养成良好的学习习惯,培养慎独的工作作风,提高实习护生综合素质,培养出适应新形势的素质型、多向型、创新型的护理人才。     

大学生学习动机、学习策略、学习投入特点及年级差异

目的:探讨大学生学习动机、学习策略、学习投入的基本情况及其在年级变量上的差异。方法:采用横断研究,对西藏3所高校的413名大学生进行问卷测查。结果:大学生学习动机总体水平一般(x珋=3.08),成就型动机维度上得分最高(x珋=3.11),在深层型动机(F=3.19,P<0.05)、成就型动机(F=2.77,P<0.05)两个维度及总体(F=2.71,P<0.05)上存在显著的年级差异;学习策略各个维度及总分上不存在显著差异;大学生学习投入呈中等水平(M/Item=4.43),奉献的分值最高(M/Item=4.61),在活力(F=8.08,P<0.001)、奉献(F=3.46,P<0.05)及总投入(F=4.89,P<0.01)上存在显著的年级差异。结论:西藏高校大学生学习动机、学习投入呈中等水平,大二学生相对较好,应加强对其他年级在动机与投入方面的激发与引导;大一学生学习策略相对较好,应加强对高年级学生学习策略的维持与优化教育。     

大学生专业承诺、学习倦怠与学习投入的关系

目的从积极心理学的视角探讨大学生专业承诺、学习倦怠与学习投入的关系。方法采用大学生专业承诺量表、学习倦怠量表和学习投入量表对306名在校大学生进行调查和统计分析。结果学习投入与专业承诺呈显著正相关,与学习倦怠成显著负相关;多元回归分析显示,学习倦怠的3个维度情绪低落、行为不当和成就感低和专业承诺的两个维度情感承诺和规范承诺对学习投入具有显著的预测作用。结论专业承诺、学习倦怠和学习投入存在密切的关系。     

高师生专业承诺及其与学习适应性、学习自我效能感的关系

目的:探讨高师生专业承诺的现状、特点及其与学习适应性、学习自我效能感的关系.方法:应用大学生专业承诺、学习适应性与学习自我效能感等量表,对665名高师生与272名非高师生进行测查.结果:①高师生与非高师生在专业承诺总分与继续承诺、理想承诺上存在显著差异,且高师生显著低于非高师生;②高师生情感承诺、规范承诺与专业承诺总分存在显著性别差异,女生高于男生;③高师生专业承诺总分及各因子水平均存在显著年级差异,且年级越高,水平越低;④高师本科生与专科生在继续承诺及专业承诺总分上均存在显著差异,专科生高于本科生.结论:高师生学习适应性及学习自我效能感各因子与专业承诺总分均存在显著正相关,并对专业承诺总分具有显著预测作用.     

Orientation, Conditioning, and Learning

Difficulties arising from failure to separate the concepts of orienting behavior, conditioning, and learning are discussed. The major reasons for ambiguity are lack of explicit definitions of terms and a tendency to overgeneralize from limited empirical demonstrations. Criteria are needed for differentiating learning, viewed generically, from conditioning, where learning is inferred from a specific stimulational arrangement. Because unlearned orienting behavior due to stimulus chaise may contribute to responses also involving learned behavior, the contribution of each needs to be assessed. At the same time, orienting behavior, as a class of behavior related to attention, may have learned as well as unlearned components. Confusion results from failure to specify assumed connotations in specific situations, as well as the experimental presuppositions involved in empirical definitions. The two basic experimental paradigms for defining learning are discussed, the control groups arrangement and the control stimuli arrangement. Data are presented to reemphasize that different paradigms may lead to quite different laws. The research task is seen as the careful utilization of variations on the paradigms with special extensions and control considerations for increasing the explanatory power of tests of learning and orientation.