首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 0 毫秒
1.
Djungarian hamsters (Phodopus sungorus) were observed in a series of laboratory tests, including home cage activity, wheel running, open-field behavior, sexual dimorphism for body mass, copulatory behavior, tonic and dorsal immobility, climbing, digging, nest building, and parental behavior. Fourteen resulting measures were compared with previous results from this laboratory from a variety of muroid species. A cluster of behavioral adaptations emerged with several marked similarities to the behaviors of a group of North American Microtus species, whereas other behaviors appeared to more closely reflect the classification of the hamsters as cricetines. It is suggested thatPhodopus andMicrotus species may have evolved many similar adaptive characteristics in response to shared environmental variables.  相似文献   

2.
Garter snakes (Thamnophis radix), hognose snakes (Heterodon platyrhinos), and rattlesnakes (Crotalus species) flick their tongues and crawl about in an open field containing no food or sexual (i.e., reproductive) odors. As Experiment I shows, the taxa differ reliably in both rate of tongue flicking and rate of locomotion. In Experiment II, garter snakes (Thamnophis radix) placed into an open field for 5 min showed more tongue flicking than snakes that were handled and placed directly back into their home cages, indicating that the first group was exploring the apparatus rather than responding only to handling. During Minutes 3 through 5 (Experiment III) in the open field, garter snakes emitted fewer tongue flicks than they did during the first minute, and after 20 min, the rate of tongue flicking was virtually zero. However, snakes were capable of responding to presentation of new objects and/or odors, indicating that the previous response decrement was not derived from effector fatigue but rather from some habituatory process. Experiment IV revealed that satiated snakes habituated more rapidly than hungry snakes during exploration of the open field. Hence, exploratory behavior in these snakes is at least partially under the control of the same factors which mediate food-related appetitive activities.  相似文献   

3.
New World primates face problems of communication distinct from those of their Old World counterparts. We suspected that the odor of urine might serve the function of communicating information among animals or troops. Two studies were conducted withSaimiri sciureus; one examined, in a laboratory enclosure, the influence of breeding season, social condition, area, and whether the urine was from known animals or from strangers, and the second measured, in a seminatural rain forest, responses to our spreadingSaimiri urine on selected sites. Enclosure and field produce the same general patterns of frequencies of behavior for urination, the urine wash and kick wash, and rubbing. The chief difference in behavior between the environments is found in the frequency of sneezing. Season (breeding or nonbreeding) is the most effective variable producing this general pattern: During the breeding season, males urine-wash throughout the enclosure or troop range, whereas during the nonbreeding season, this behavior is restricted in location, at least in the enclosure. At this time, females increase their frequencies of sniffing and rubbing. Many of these behaviors are observed only in special locations of the enclosure. The results show thatSaimiri respond differently to the urine of known and foreign animals, depending upon the season and whether they are with members of their own sex or both sexes. It is suggested that primates not equipped with specialized organs for scent marking may use urine opportunistically to communicate.  相似文献   

4.
This study describes the effects of ability-paired student interactions on achievement as fifth graders (10-year-olds) worked on laboratory activities relating to balance. Achievement gains were assessed (n = 83) by analysis of pretest–posttest differences on the lever concept test. Audio recordings and field notes (n = 30) were analyzed for the following laboratory behaviors: number of words spoken, tinkering, block moving, turns speaking, incidence of helping and distracting behavior. Results revealed that: (1) low-ability student achievement is greater when students are paired with high-ability partners; (2) low-ability students speak more words, exhibit less distracting behavior, and move blocks on the lever less when they are paired with a partner of high ability; (3) high-ability students speak more words, take more turns speaking, and exhibit more helping behaviors when they are paired with low-ability students rather than with other high ability students; and (4) there are no achievement differences for high-ability students regardless of the ability level of their partner. These findings suggest that heterogeneous grouping of students in science can be beneficial to low-ability students partnered with high-ability students, without being detrimental to the high-ability partners.  相似文献   

5.
The simultaneous sorption behavior and characteristics of cadmium (Cd) and sulfamethoxazole (SMX) on rice straw biochar were investigated. Isotherms of Cd and SMX were well modeled by the Langmuir equation (R2 >0.95). The calculated maximum adsorption parameter (Q) of Cd was similar in single and binary systems (34129.69 and 35919.54 mg/kg, respectively). However, the Q of SMX in a binary system (9182.74 mg/kg) was much higher than that in a single system (1827.82 mg/kg). The presence of Cd significantly promoted the sorption of SMX on rice straw biochar. When the pH ranged from 3 to 7.5, the sorption of Cd had the characteristics of a parabola pattern with maximum adsorption at pH 5, while the adsorption quantity of SMX decreased with increasing pH, with maximum adsorption at pH 3. The amount of SMX adsorbed on biochar was positively correlated with the surface area of the biochar, and the maximum adsorption occurred with d 250 biochar (biochar with a diameter of 150-250 μm). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that the removal of Cd and SMX by rice straw biochar may be attributed to precipitation and the formation of surface complexes between Cd or SMX and carboxyl or hydroxyl groups. The results of this study indicate that rice straw biochar has the potential for simultaneous removal of Cd and SMX from co-contaminated water.  相似文献   

6.
The purposes of this study were to determine the extent and types of parent involvement in Head Start programs, and to examine the relations between parent participation and family, teacher and classroom characteristics. Parents (n = 1131) and teachers (n = 59) from four Head Start programs participated. Data were gathered through volunteer logs, parent interviews, teacher questionnaires, and classroom observations. The most frequent type of parent involvement activity was helping out in the classroom, followed by attendance at parent meetings. This pattern was consistent across the year (fall or spring), and across total amount of participation (i.e. parents participating one, two, three or more times in the year). Parent employment was the strongest predictor of parent involvement compared to other parent characteristics. Among teacher and classroom characteristics, classroom quality was the strongest predictor of parent involvement. Also, teachers with more years of experience in Head Start had more total hours of volunteering in their classrooms and had volunteers returning more times. Teachers’ reports of the involvement of parents in their classrooms were moderately correlated with volunteer logs, while parent self-reports of their involvement were only modestly correlated with volunteer logs, indicating that teachers may be more accurate than parents when reporting parent involvement activities.  相似文献   

7.
We use administrative data from Ireland to study differences in college application behavior between students from disadvantaged versus advantaged high schools. Ireland provides an interesting laboratory for this analysis as applicants provide a preference-ordering of college programs (majors) and marginal applications are costless. Also, college admission depends almost completely on grades in the terminal high school examinations. Thus, we can compare the application choices of students who have equal chances of admission to college programs. Conditional on achievement and college opportunities, we find that students from advantaged high schools are more likely to apply to universities and to more selective college programs. They are also more likely to have preferences that cluster by program selectivity rather than by field of study. Our results suggest that, alongside differences in achievement, differences in college application behavior also cause persons from advantaged high schools to be more likely to enrol in selective colleges and enter more selective programs. Importantly, we find that enrolment gaps for equally qualified applicants are smaller than differences in application behavior; the relatively meritocratic centralized admissions system based on achievement undoes much of the effect of the differences in application behavior.  相似文献   

8.
The mechanical behavior of sand is very complex, and depends on factors including confining pressure, density, and drainage condition. A soil mass can be contractive or dilative when subjected to shear loading, and eventually reaches an ultimate state, referred to as the critical state in soil mechanics. Conventional approach to explore the mechanical behavior of sand mainly relies on the experimental tests in laboratory. This paper gives an alternative view to this subject using discrete element method （DEM）, which has attracted much attention in recent years. The implementation of the DEM is carried out by a series of numerical tests on granular assemblies with varying initial densities and confining pressures, under different test configurations. The results demonstrate that such numerical simulations can produce correct responses of the sand behavior in general, including the critical state response, as compared to experimental observations. In addition, the DEM can further provide details of the microstructure evolutions during shearing processes, and the resulting induced anisotropy can be fully captured and quantified in the particle scale.  相似文献   

9.
Two passerine species, black-capped chickadees (Parus atricapillus, a food-storing bird) and darkeyed juncos (Junco hyemalis, a nonstoring bird) were compared in a task in which they inspected four feeders in an aviary. Different feeders and different spatial locations were used on each trial. One of the feeders was baited. The subjects returned after a 5-min retention interval to find the baited feeder. Tests with transformations of the feeder array made it possible to determine what cues controlled the food-finding behavior. Chickadees responded to spatial cues preferentially over local color and pattern cues associated with the feeder (Experiments 2–4). The same ordering of responding was found in Experiment 1, a food-storing version of the food-finding task outlined above. Experiment 5 tested juncos on the food-finding task. Juncos responded to all types of information equally. The results are discussed in relation to the notion that because of their food-storing lifestyle, chickadees may need to rely more heavily on spatial cues than do juncos.  相似文献   

10.
94 mothers with 2-year-old children were interviewd about their employment, role satisfaction, and social support and were observed in their homes at dinnertime and in a laboratory compliance task. Hierarchical multiple regressions were used to test main effects of employment, hours employed, and their interactions. Maternal employment adversely affected maternal behavior when satisfaction with social support or with the work role was low, but only in the laboratory. Positive main effects of employment on maternal behavior were observed in the home: employed mothers used less power assertion with their children. Mothers who worked longer hours used more guidance and were more responsive to their children in both settings. In both settings, the effect of poor-quality care on child behavior was greater when mothers were employed, and, in the laboratory, boys of employed mothers were more defiant than boys of nonemployed mothers and girls of employed mothers. Boys with more than one current arrangement were more likely than similarly situated girls to be defiant in the laboratory, but they were also less likely than girls to be cared for by fathers.  相似文献   

11.
The more people believe in a just world (BJW) in which they get what they deserve, the more they are motivated to preserve a just world by ones’ just behavior. Consequently, we expected school students with a strong BJW to show less deviant behavior as cheating or delinquency. The mediating role of teacher justice was also examined. Questionnaire data were obtained from a total of N?=?382 German and Indian high school students. Regression analyses revealed that the stronger students’ BJW was, the less cheating and delinquent behavior they reported. Moreover, the more the students believed in a just world, the more they evaluated their teachers’ behavior toward them personally to be just, and the experience of teacher justice fully mediated the relation between BJW and cheating and delinquency, respectively. This pattern of results was in line with our hypotheses and consistent across different cultural contexts. It persisted when neuroticism and sex were controlled. The adaptive functions of BJW and implications for future school research are discussed.  相似文献   

12.
Two groups of disadvantaged Afro-American children, a total of 30 boys and 25 girls, mean age about 42 months; and two groups of middle- and upper-middle-class children, most of them white, 35 boys and 31 girls, mean age about 44.5 months, were observed for patterns of sex-role-characteristic behavior and peer and teacher response to such behavior. At all times, the children in the two experimental groups were being taught by seven women and seven or eight men, about half of whom were Afro-American, half white-Anglo, and who were mixed in the two schools by race but evenly divided by sex. Boys engaged in 16% sex-characteristic behavior, 5.7% cross-sex behavior. The same figures for girls were 18 and 6%. There were no pattern or percentage differences by race or social status of children. Women teachers gave most of their sex-role connected rewards for feminine behavior to both boys and girls. Men teachers rewarded more equably, masculine behaviors for boys, feminine behaviors for girls. Children rewarded mainly their own sex, and gave rewards for sex characteristic behavior. The pattern was even clearer for boys than for girls. In Discussion, comparisons are made with other somewhat similar studies.  相似文献   

13.
12-month-olds were seen with their mothers and fathers in a laboratory procedure designed to compare infants' solicitation of, emotional resonance to, and self-regulation on the basis of happy, fearful, and conflicting emotional signals from mothers versus fathers. Measures of positive and negative affect and affect lability; of look, approach, and proximity behavior; and of overall response pattern were obtained. Infants showed more positive and less negative affect and greater toy proximity with happy compared to fearful signals. Few differences emerged in infants' referencing response to mothers versus fathers. Infants looked more to mothers than fathers when no signals were given but did not differentiate between parents when only one was signaling or when both were signaling (conflict). In affective state and behavioral regulation, they were not differentially responsive to maternal versus paternal signals either when only one parent was signaling or when both were giving signals.  相似文献   

14.
在开挖底面低于地下水位的基坑时，有时会发生流砂现象。造成严重后果。为此如何防治流砂成为基坑土方施工需要解决的一个技术难题。根据工程实例，分析流砂产生原因和条件。探讨有效的防治措施和有关技术问题。  相似文献   

15.
Reactivity to a reward is affected by prior experience with the different reinforcer values of that reward, a phenomenon known as incentive relativity, which can be studied using the consummatory succesive negative contrast (cSNC) paradigm, in which the performance of animals that receive a 4 % sucrose solution after trials on which they were exposed to 32 % sucrose is compared with that of subjects that always receive the 4 % sucrose solution. The exploration of a novel open field can enhance or block the acquisition of associative and nonassociative memories. The effect of open field on cSNC has not yet been explored. The main result of the present study was that open-field exposure significantly modified the expression of cSNC. Exposure to an open field 1 h but not immediately before the downshift interfered with the expression of cSNC. These animals drank more of the downshifted reward than did controls that were not exposed to the apparatus, and this behavior persisted for up to three recovery trials. This phenomenon was observed even when the animals were given a more protracted preshift phase and when the discrepancy between the preshift and shift incentive values of sucrose were increased. An open field also interfered with incentive downshift when open-field exposure occurred 6 h before the downshift, and repeated exposure to the apparatus did not deteriorate this effect. The present study adds to a growing body of literature that indicates that open-field exploration can interfere with memory formation.  相似文献   

16.
Chemistry instructors in teaching laboratories provide expert modeling of techniques and cognitive processes and provide assistance to enrolled students that may be described as scaffolding interaction. Such student support is particularly essential in laboratories taught with an inquiry-based curriculum. In a teaching laboratory with a high instructor-to-student ratio, mobile devices can provide a platform for expert modeling and scaffolding during the laboratory sessions. This research study provides data collected on the effectiveness of podcasts delivered as needed in a first-semester general chemistry laboratory setting. Podcasts with audio and visual tracks covering essential laboratory techniques and central concepts that aid in experimental design or data processing were prepared and made available for students to access on an as-needed basis on iPhones® or iPod touches®. Research focused in three areas: the extent of podcast usage, the numbers and types of interactions between instructors and student laboratory teams, and student performance on graded assignments. Data analysis indicates that on average the podcast treatment laboratory teams accessed a podcast 2.86 times during the laboratory period during each week that podcasts were available. Comparison of interaction data for the lecture treatment laboratory teams and podcast treatment laboratory teams reveals that scaffolding interactions with instructors were statistically significantly fewer for teams that had podcast access rather than a pre-laboratory lecture. The implication of the results is that student laboratory teams were able to gather laboratory information more effectively when it was presented in an on-demand podcast format than in a pre-laboratory lecture format. Finally, statistical analysis of data on student performance on graded assignments indicates no significant differences between outcome measures for the treatment groups when compared as cohorts. The only statistically significant difference is between students who demonstrated a high level of class participation in the concurrent general chemistry lecture course; for this sub-group the students in the podcast treatment group earned a course average that was statistically significantly higher than those in the lecture treatment group.  相似文献   

17.
Eye movements of stumptailed monkeys were measured during learning of a pattern discrimination problem. Amount of scanning (shifts in visual fixation from one pattern to the other) increased once learning began and reached a maximum either at about the point that frequency of correct responses reached asymptote or just after that. These results, taken together with earlier findings on vicarious trial and error and operant observing behavior, suggest that this is the characteristic pattern of change in frequency of observing during visual discrimination learning. A change in information processing strategy is proposed as one explanation for these results. Duration of the last fixation on a discriminative stimulus during a trial showed similar, though not identical, changes with practice. The decrease in duration of the last fixation following learning contrasts with results of prior studies involving more complex tasks, and supports our conclusion that the duration of the last fixation is particularly sensitive to the cognitive processing requirements of the discriminative task.  相似文献   

18.
One line of research on student understanding of complex systems has tended to emphasize discontinuities between common misconceptions and relatively more sophisticated understandings. Other work has focused on instruction while acknowledging the existence of other ways of understanding complex systems, but less emphasis has been on examining the knowledge structures within these intermediate ways of understanding. This study takes a microgenetic approach to examining student’s explanations for the behavior of complex systems. Using the Knowledge-in-Pieces epistemological perspective, the analysis documents a continuity of reasoning patterns across less prototypically centralized and more prototypically decentralized (a more sophisticated causality) explanations while explaining the movement of sand dunes. The first analysis examines 31 interviews and shows that many reflected a general reasoning pattern that encompassing some combination of an initial centralized explanation, a final decentralized explanation, and transitional explanations. A second analysis examines a single student’s reasoning pattern and finds that the activation of relevant intuitive knowledge pieces (p-prims) and transitional explanations function as threads of continuity across the continuum of reasoning patterns. These findings suggest that students are able to exhibit a continuity of reasoning patterns across centralized to decentralized causality and are able to access productive intuitive knowledge about complex systems that are applicable to both the macro and micro levels of sand dune movement. Implications suggest that future research investigate these transitional explanations along with the mechanisms of shifting explanations that can account for this robust continuum.  相似文献   

19.
父母教养方式研究的新进展   总被引：5，自引：0，他引：5  
父母教养方式是父母教养观念、教养行为及其对儿童情感表现的一种组合方式,反映了亲子交往的实质。本文从四个方面概括总结了该领域内研究的新进展:(1)研究范式从亲子单向决定观向亲子系统观转变;(2)研究方法从传统单一化向现代综合化转变;(3)研究内容从单纯类型化影响研究向影响教养方式的多因素研究转变;(4)研究重心由理论研究向应用研究转变。并就这些转变和已有研究带来的问题,提出了前景展望。  相似文献   

20.
The goal of the present study was to explore the interface between young children’s socio-emotional characteristics and the nature of their interactions with teachers. The participants in this study were 135 preschool children (62 males and 73 females, Mage=48.68 months, SD=8.30 months). Children’s interaction with teachers and play behaviors were observed during teacher-supervised free play with peers. Teachers also rated child behavior problems and social competence. Three groups of children (representing n=76 children) were identified based on the frequency and the nature of their interactions with teachers. Children who most frequently initiated interactions with teachers behaved and were rated by teachers as being more aggressive than their comparison peers. In contrast, children who most frequently received initiations from teachers were more shy and anxious than their peers. Finally, children who spent less time with teachers were more sociable, less solitary, and evidenced fewer behavior problems than peers who interacted more frequently with teachers. Implications for early-childhood educators are discussed in terms of outcomes that may be associated with overly dependent teacher–child relationships.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号