Dielectric and spectrometric investigations of binary mixtures of tetrahydrofuran with propionic acid

The static permittivity (ε_m ) and the permittivity at the high-frequency limit (ε_∞m ) of a binary mixture of propionic acid with tetrahydrofuran (THF) have been determined for different concentrations at temperatures of 303, 308, 313, and 318 K. The data have been used to compute the Kirkwood correlation factor, the excess permittivity, and the excess free-energy of the mixtures. The Kirkwood correlation factor is found to increase with increasing THF concentration. The mixture exhibited positive values of the excess permittivity and negative values of the excess free-energy of mixing, respectively. UV-Vis and FT-IR spectral measurements have also been carried out. The observed bathochromism and hypochromism in the UV-Vis spectra have been explained in terms of complex formation and ordering of dipoles of the complex. The FT-IR spectrum of the mixture shows considerable shifts in the positions of some of the absorption bands, indicating extensive hydrogen bonding between solute and solvent molecules.     

‘I feel better when…’: An analysis of the memory-experience gap for peoples’ estimates of the relationship between health behaviours and experiences

Objective: People often overestimate how strongly behaviours and experiences are related. This memory-experience gap might have important implications for health care settings, which often require people to estimate associations, such as “my mood is better when I exercise”. This study examines how subjective correlation estimates between health behaviours and experiences relate to calculated correlations from online reports and whether subjective estimates are associated with engagement in actual health behaviour.

Design: Seven-month online study on physical activity, sleep, affect and stress, with 61 online assessments.

Main Outcome Measures: University students (N = 168) retrospectively estimated correlations between physical activity, sleep, positive affect and stress over the seven-month study period.

Results: Correlations between experiences and behaviours (online data) were small (r = ?.12–.14), estimated correlations moderate (r = ?.35–.24). Correspondence between calculated and estimated correlations was low. Importantly, estimated correlations of physical activity with stress, positive affect and sleep were associated with actual engagement in physical activity.

Conclusion: Estimation accuracy of relations between health behaviours and experiences is low. However, association estimates could be an important predictor of actual health behaviours. This study identifies and quantifies estimation inaccuracies in health behaviours and points towards potential systematic biases in health settings, which might seriously impair intervention efficacy.     

Emergent stimulus relations depend on stimulus correlation and not on reinforcement contingencies

We aimed to investigate whether novel stimulus relations would emerge from stimulus correlations when those relations explicitly conflicted with reinforced relations. In a symbolic matching-to-sample task using kanji characters as stimuli, we arranged class-specific incorrect comparison stimuli in each of three classes. After presenting either Ax or Cx stimuli as samples, choices of Bx were reinforced and choices of Gx or Hx were not. Tests for symmetry, and combined symmetry and transitivity, showed the emergence of three 3-member (AxBxCx) stimulus classes in 5 of 5 human participants. Subsequent tests for all possible emergent relations between Ax, Bx, Cx and the class-specific incorrect comparisons Gx and Hx showed that these relations emerged for 4 of 5 the participants after extended overtraining of the baseline relations. These emergent relations must have been based on stimulus-stimulus correlations, and were not properties of the trained discriminated operants, because they required control by relations explicitly extinguished during training. This result supports theoretical accounts of emergent relations that emphasize stimulus correlation over operant contingencies.     

Population models and simulation methods: The case of the Spearman rank correlation

The purpose of this paper is to highlight the importance of a population model in guiding the design and interpretation of simulation studies used to investigate the Spearman rank correlation. The Spearman rank correlation has been known for over a hundred years to applied researchers and methodologists alike and is one of the most widely used non‐parametric statistics. Still, certain misconceptions can be found, either explicitly or implicitly, in the published literature because a population definition for this statistic is rarely discussed within the social and behavioural sciences. By relying on copula distribution theory, a population model is presented for the Spearman rank correlation, and its properties are explored both theoretically and in a simulation study. Through the use of the Iman–Conover algorithm (which allows the user to specify the rank correlation as a population parameter), simulation studies from previously published articles are explored, and it is found that many of the conclusions purported in them regarding the nature of the Spearman correlation would change if the data‐generation mechanism better matched the simulation design. More specifically, issues such as small sample bias and lack of power of the t‐test and r‐to‐z Fisher transformation disappear when the rank correlation is calculated from data sampled where the rank correlation is the population parameter. A proof for the consistency of the sample estimate of the rank correlation is shown as well as the flexibility of the copula model to encompass results previously published in the mathematical literature.     

Social rank, interpersonal trust and recall of parental rearing in relation to homesickness

This study set out to explore the relationship between recall of parental rearing, social rank, interpersonal trust and homesickness. Eighty-nine first year undergraduates (59 women and 30 men) living away from home and attending the University of Derby completed a set of questionnaires in their sixth week in the first semester at university. Results indicate that recall of supportive parenting is associated with lower homesickness, favourable social rank and greater interpersonal trust. Conversely, recall of parental rejection correlated with great homesickness, feeling inferior to others, and lower interpersonal trust. Two separate multiple regression analyses revealed that both the parental rearing variables, and the social rank and interpersonal trust variables, produced significant models in the prediction of homesickness scores. Mediation analysis suggests that whilst recalling one’s parents as rejecting is directly associated with increased homesickness, it may also generate feelings of inferiority that may lead to distress when moving into new environments.     

Exact Interval Estimation, Power Calculation, and Sample Size Determination in Normal Correlation Analysis

This paper considers the problem of analysis of correlation coefficients from a multivariate normal population. A unified theorem is derived for the regression model with normally distributed explanatory variables and the general results are employed to provide useful expressions for the distributions of simple, multiple, and partial-multiple correlation coefficients. The inversion principle and monotonicity property of the proposed formulations are used to describe alternative approaches to the exact interval estimation, power calculation, and sample size determination for correlation coefficients. The author thanks the referees for their constructive comments and helpful suggestions and especially the associate editor for drawing attention to several critical results which led to substantial improvements of the exposition. The work for this paper was initiated while the author was visiting the Department of Statistics, Stanford University. This research was partially supported by National Science Council Grant NSC-94-2118-M-009-004. Request for reprints should be sent to Gwowen Shieh, Department of Management Science, National Chiao Tung University, Hsinchu, Taiwan 30050, ROC.     

中学生完美主义特点及其与亲社会倾向的关系

本研究使用修订后的Hewitt多维完美主义量表(HMPS)和亲社会倾向量表(PTM),对中学生群体进行了测查,并采用简单相关、典型相关和回归分析等方法,探讨中学生完美主义特点及其与亲社会倾向的关系。结果表明:(1)中学生在指向自我完美主义上得分最高,其次是社会期望完美主义,指向他人完美主义得分最低。(2)中学生的亲社会倾向由高到低依次为:利他的、情绪的、紧急的、依从的、匿名的和公开的。(3)指向自我完美主义与六类亲社会倾向都正相关,但指向他人完美主义、社会期望完美主义仅与公开的亲社会倾向正相关。从典型相关分析结果看,典型变量所代表的亲社会倾向主要是利他的、依从的、公开的亲社会倾向,而这些亲社会倾向主要由指向自我完美主义、指向他人完美主义来解释。(4)回归分析发现,除去年级、性别、学校类型的作用外,指向自我完美主义对公开的、匿名的、利他的、依从的、情绪的、紧急的等六类亲社会倾向的解释力分别为2.6%、2.8%、7.2%、7.4%、7.0%、5.0%。     

不同年龄妇科患者痛阈测试及其临床意义

采用双盲、前瞻性研究,选择90例妇科择期全麻下子宫肌瘤剔除或子宫全切手术患者,ASA分级Ⅰ或Ⅱ级,按年龄分两组,中青年组（A组）50例,年龄25岁～50岁,老年组（B组）40例,年龄60岁-80岁,术前使用电刺激测定并记录患者的痛阈和耐痛阈,观察不同年龄妇科患者痛阈和耐痛阈以及两者之间相关性。结果显示A组与B组痛阈分别为（1．86±0．51）mA和（1．89±0．66）mA差异无统计学意义;A组比B组耐痛阈低分别为（6．16±2．53）mA和（8．40士3．21）mA,差异有统计学意史;A组痛阈与耐痛阈之间有相关性（Spearman相关系数为-0．42,P〈0．05）;B组痛阈与耐痛阈之间无相关性。因此,老年患者耐痛阈升高,中青年患者术前痛阈和耐痛闽均可预测术后疼痛,老年患者术前痛阈不能预测术后疼痛。     

How does dominance rank status affect individual and social learning performance in the dog (<Emphasis Type="Italic">Canis familiaris</Emphasis>)?

Dogs can learn effectively to detour around a V-shaped fence after observing a demonstration from either an unfamiliar human or dog demonstrator. We found earlier that there is substantial individual variation between the dogs’ performance, even when using the same experimental conditions. Here, we investigate if the subjects’ relative dominance rank with other dogs had an effect on their social learning performance. On the basis of the owners’ answers to a questionnaire, subjects from multi-dog homes were sorted into groups of dominant and subordinate dogs. In Experiment 1, dominant and subordinate dogs were tested without demonstration and we did not find any difference between the groups—they had similarly low detour performances on their own. In Experiment 2 and 3, dogs from single dog and multi-dog households were tested in the detour task with demonstration by an unfamiliar dog, or human, respectively. The results showed that social learning performance of the single dogs fell between the dominant and subordinate multi-dogs with both dog and human demonstration. Subordinate dogs displayed significantly better performance after having observed a dog demonstrator in comparison to dominant dogs. In contrast, the performance of dominant and subordinate dogs was almost similar, when they observed a human demonstrator. These results suggest that perceived dominance rank in its own group has a strong effect on social learning in dogs, but this effect seems to depend also on the demonstrator species. This finding reveals an intricate organization of the social structure in multi-dog households, which can contribute to individual differences existing among dogs.