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481.
G Collier D F Johnson G Borin C E Mathis 《Journal of the experimental analysis of behavior》1994,62(2):169-184
Rats in a laboratory foraging paradigm searched for sequential opportunities to drink in two water patches that differed in the bar-press price of each "sip" (20 licks) of water within a bout of drinking (Experiment 1) or the price and size (10, 20, or 40 licks) of each sip (Experiment 2). Total daily water intake was not affected by these variables. The rats responded faster at the patch where water was more costly. However, they accepted fewer opportunities to drink, and thus had fewer drinking bouts, and drinking bouts were smaller at the more costly patch than at the other patch. This resulted in the rats consuming a smaller proportion of their daily water from the more costly patch. The size of the differences in bout frequency and size between the patches appears to be based on the relative cost of water at the patches. The profitability of each patch was calculated in terms of the return (in milliliters) on either effort (bar presses) or time spent there. Although both measures were correlated with the relative total intake, bout size, and acceptance of opportunities at each patch, the time-based profitability was the better predictor of these intake measures. The rats did not minimize bar-press output; however, their choice between the patches and their bout sizes within patches varied in a way that reduced costs compared to what would have been expended drinking randomly. These data accord well with similar findings for choices among patches of food, suggesting that foraging for water and food occurs on the basis of comparable benefit-cost functions: In each case, the amount consumed is related to the time spent consuming. 相似文献
482.
483.
项目曝光控制和内容约束关系到测验安全、测验的信度和效度, 是计算机化自适应测验(Computerized Adaptive Testing, CAT)中两类重要的非统计约束条件。本文在认知诊断CAT中针对内容约束和项目曝光控制要求, 运用5种方法选择测验项目。它们分别是:(1) Monte Carlo方法与项目合格方法相结合, 记为MC-IE; (2) Monte Carlo方法与最大优先指标方法相结合, 记为MC-MPI; (3) Monte Carlo方法与限制阈值方法相结合, 记为MC-RT; (4) Monte Carlo方法与限制进度指标方法相结合, 记为MC-RPG以及(5) Monte Carlo方法与最大后验概率方法相结合, 记为MC-PP。然后通过在线性、收敛、发散、无结构和独立五种属性结构下构建题库并运用重参化融融统和模型模拟被试反应比较它们的选题表现。研究发现, (1) 相同选题方法在不同属性结构下项目曝光率的分布类似, 测量精度按线性、收敛、发散、无结构和独立结构的顺序依次降低; (2) 相同属性结构下, 不同方法的测量精度高低依次为MC-PP、MC-IE、MC-RT、MC-MPI和MC-RPG方法; 项目曝光均匀性优劣依次为MC-RPG、MC-MPI、MC-RT、MC-IE和MC-PP方法。统一量纲值表明, MC-RPG方法的综合表现最好, MC-MPI方法的表现次之。 相似文献
484.
降低剖宫产率 维护母婴利益 总被引:9,自引:1,他引:8
陆于宏 《医学与哲学(人文社会医学版)》2005,(12)
剖宫产作为一种生产方式,其比率居高不下,已经引起医学界和卫生管理部门的重视。分析其原因,开展相应的对策研究,已成为当务之急。通过健康教育使产妇走出认识误区;加强医务人员职业道德建设;加强医疗卫生法制建设;完善医疗卫生管理体制;建立和谐的医患关系是降低剖宫产比率,维护母婴利益的重要保证。 相似文献
485.
实验采用RSVP任务,考察了汉字加工中呈现速率对重复知盲效应的影响,结果发现:(1)在加工汉字重复刺激时,存在着重复知肓(RB)效应,其强度随着呈现速率的变化而改变,当呈现速率较快时,正确率较低,呈现速率较慢时,正确率较高;(2)与加工英文信息比较,在汉字加工中,RB效应的出现似乎推迟了一段时间,这可能从另一方面反映出加工汉字比英文需要不同的加工时间.即加工信息的难易程度也影响RB效应出现的时间。 相似文献
486.
提出两种认知诊断计算机自适应测验下平衡属性收敛的新方法(MABI、RTA),模拟研究系统探讨和比较了此二者与已有方法(ABI、IABI和RABI)的表现。结果发现:(1)新方法较不考虑属性收敛的方法有更高的准确率以及更均衡的题目使用率;(2)新方法较ABI和RABI有稍低的准确性,但有更平衡的题目使用率;(3)新方法与IABI的准确性和题目使用率在不同选题策略下各有合优势。总之,两种新方法较好地兼顾测量准确性、题目使用率以及题库曝光情况。 相似文献
487.
Marilyn G. Boltz 《Memory (Hove, England)》2017,25(10):1309-1326
Two experiments examined the ability to remember the vocal tempo and pitch of different individuals, and the way this information is encoded into the cognitive system. In both studies, participants engaged in an initial familiarisation phase while attending was systematically directed towards different aspects of speakers’ voices. Afterwards, they received a tempo or pitch recognition task. Experiment 1 showed that tempo and pitch are both incidentally encoded into memory at levels comparable to intentional learning, and no performance deficit occurs with divided attending. Experiment 2 examined the ability to recognise pitch or tempo when the two dimensions co-varied and found that the presence of one influenced the other: performance was best when both dimensions were positively correlated with one another. As a set, these findings indicate that pitch and tempo are automatically processed in a holistic, integral fashion [Garner, W. R. (1974). The processing of information and structure. Potomac, MD: Erlbaum.] which has a number of cognitive implications. 相似文献
488.
Stéphane Guay Nadim Nachar Marc E. Lavoie André Marchand Kieron P. O’Connor 《Anxiety, stress, and coping》2017,30(1):52-65
Background and objectives: Social support is one of the three strongest predictors of posttraumatic stress disorder (PTSD). In the present study, we aimed to assess the buffering power of overt socially supportive and unsupportive behaviors from the significant other, in a group with PTSD and a comparison group. Design and methods: A total of 46 individuals with PTSD and 42 individuals with obsessive-compulsive disorder (OCD) or panic disorder (PD) completed diagnostic interviews and an anxiety-oriented social interaction with a significant other. Heart rate of participants was continuously measured during this interaction and overt social behaviors from the significant other were recorded on videotape and coded using a validated system. Results: Changes in heart rate in PTSD participants correlated negatively with changes in overt socially supportive behaviors from their significant other (r from ?.36 to ?.50, p?<?.05), while changes in overt unsupportive social behaviors from their significant other did not yield any significant correlation (r from ?.01 to .05, p?>?.05). No such statistically significant association emerged in the group with OCD or PD (r from .01 to ?.27, p?>?.05). Conclusions: This study sustain the buffering power of overt supportive behaviors from the significant other on heart rate changes in PTSD. 相似文献
489.
ObjectivesRelative age effects exist across sports and cultures (Cobley, Baker, Wattie, & McKenna, 2009), though a recent, unusual trend is females born in the second quartile of the selection year are most over-represented on elite teams. The first purpose of this study was to test the hypothesis that the second-quartile phenomenon was the result of first-quartile female athletes registering to play male sport. Due to the nature of the collected data, a secondary purpose was to examine relative age effects across female age divisions.DesignCross-sectional, with multiple chi-square analyses.MethodPlayers included 29,924 female ice hockey players (ages 7–17 years) from the Ontario Hockey Federation. Birthdates were converted into quartiles following the Hockey Canada selection year.ResultsRelative age effects (with the second quartile most over-represented) existed for the entire sample (χ2 [3, 29923] = 401.95, p < 0.001), those registered for female ice hockey (χ2 [3, 24984] = 369.90, p < 0.001) and those registered for male ice hockey (χ2 [3, 4938] = 37.88, p < 0.001). The strength of the effect lessened as athletes aged.ConclusionIt appears the second-quartile phenomenon cannot be explained by athletes’ choice to play male sport. Further, female relative age effects appear strongest at younger ages. The discussion includes integration of results with previous literature, along with plausible explanations. 相似文献
490.
《Journal of Investigative Psychology & Offender Profiling》2017,14(1):23-42
The present study was designed to establish the base rate of alibis and supportive evidence for alibis of non‐offenders. That is important because the presence and lack of an alibi are often seen as a clear indicator of innocence and guilt, respectively, of a suspect. A large sample of laypersons (N = 841) was randomly assigned to one of 32 conditions in which they were asked to generate a true alibi after they were falsely accused of being the perpetrator of a mock robbery. Each condition consisted of either a Tuesday or a Saturday and one of 16 timeframes. In general, the majority of the participants had an alibi (99.5%) and supportive evidence for their alibis (92.4%). The supportive evidence often consisted of a combination of supportive evidence rather than one distinct form of supportive evidence (33.3%). Although it is widely assumed that the alibi believability is determined based on the strength of the supportive evidence, our results show that the type of evidence that can be presented by laypeople depends upon the day and the timeframe wherein the crime has been committed. The results of the study therefore imply that determining alibi believability solely on the strength of the supportive evidence is not a fair measure. We suggest that the believability should also be based on the base rate of alibis and its supportive evidence. 相似文献