The effects of varying the duration of grain presentation on negative automaintenance in the pigeon

The purpose of this study was to assess the effects of varying hopper duration on negative automaintenance in the pigeon. These effects were assessed in six experimental Ss by exposing them to either two-, four-, or eight-second hopper durations. A fixed trial negative contingency in which a peck's only consequence was to cancel grain for that trial was in effect at all times. Trials consisted of an eight-second illumination of a response key programmed on a VT 30-second schedule. In all conditions, the percent of trials with at least one peck remained roughly constant across all subjects. Average latencies across Ss decreased as the hopper duration increased. Individual Ss manifested this effect most clearly in the difference between the eight-second and the two shorter conditions. This effect is consistent with effects of similar manipulations done in the context of Pavlovian conditioning. An analysis of sequential dependencies within and across sessions showed that there is a tendency for the number of trials with a peck to oscillate in successive sessions. No dependencies of this sort were discovered on a within session basis. It is suggested that specific mechanisms be defined by experimenter operations as the mechanisms of behavioral control

The effects of varying the trace interval, cs duration, and inter-reinforcement interval on key pecking in the pigeon

When the illumination of a response key is followed by grain presentation, pigeons come to peck at the lighted key. Stimulus-reinforcer relationships in this procedure have been shown to exert a strong influence on the development and maintenance of responding. The control exerted by stimulus-reinforcer relationships was investigated by exposing groups of pigeons to procedures that differed according to the duration of the various intervals defined by the stimulus changes in this procedure. In the first phase of the experiment, variations in the time from keylight offset to grain onset produced an inverse relationship between several measures of the tendency to respond and the duration of the trace interval. The tendency to respond decreased as the duration of the key illumination was increased and the tendency to respond decreased as the interreinforcement interval was shortened. The effects of these three manipulations were summarized by an inverse relationship between the tendency to respond and a variable A. This variable is formed by dividing the duration of the interstimulus interval by the duration of the interreinforcement interval and multiplying this quantity by the quotient produced by dividing the duration of the interstimulus interval by the CS duration. The within-CS response patterns indicated that subjects tended to respond soon after CS onset or not at all. Those subjects that did not respond much during the first phase of the experiment were exposed to a second procedure. The results of the second phase replicated the findings of the earlier portion of the experiment and, additionally, demonstrated that the transfer from Phase I to Phase II was related to the Phase I A. Predictions based on recently proposed contingency models of conditioning were not entirely consistent with the results of both phases of the experiment. A model based solely on temporal parameters was developed and the predictions based on this model were shown to be in accord with the results of the experiment

Self-rated health and its determinants among adults in Syria: a model from the Middle East

<p>Abstract</p> <p>Background</p> <p>Self-rated health (SRH) has been widely used to research health inequalities in developed western societies, but few such studies are available in developing countries. Similar to many Arab societies, little research has been conducted in Syria on the health status of its citizens, particularly in regards to SRH. This Study aims to investigate and compare determinants of SRH in adult men and women in Aleppo, Syria.</p> <p>Methods</p> <p>A cross-sectional survey of adults 18 to 65 years old residing in Aleppo (2,500,000 inhabitants), Syria was carried out in 2004, involving 2038 household representatives (45.2% men, age range 18–65 years, response rate 86%). SRH was categorized as excellent, normal, and poor. Odds ratios for poor and normal SRH, compared to excellent, were calculated separately for men and women using logistic regression.</p> <p>Results</p> <p>Women were more likely than men to describe their health as poor. Men and women were more likely to report poor SRH if they were older, reported two or more chronic health problems, or had high self perceived functional disability. Important gender-specific determinants of poor SRH included being married, low socioeconomic status, and not having social support for women, and smoking, low physical activity for men.</p> <p>Conclusion</p> <p>Women were more likely than men to describe their health as poor. The link with age and pre-existing chronic conditions seems universal and likely reflects natural aging process. Determinants of SRH differed between men and women, possibly highlighting underlying cultural norms and gender roles in the society. Understanding the local context of SRH and its determinants within the prevailing culture will be important to tailor intervention programs aimed at improving health of the Syrian and similar Arab societies.</p

Testing a model of minority identity achievement, identity affirmation, and psychological well-being among ethnic minority and sexual minority individuals

How is social identity related to psychological well-being among minority individuals? Drawing on developmental models of identity formation (e.g., Erikson, 1968) and on Social Identity Theory (Tajfel & Turner, 1979), we tested a conceptual model examining links between two key aspects of social identity and psychological well-being. We proposed that the association between identity achievement (exploring and understanding the meaning of one\u27s identity) and psychological well-being is mediated by identity affirmation (developing positive feelings and a sense of belonging to one\u27s social group). Across three studies, including ethnic minority high school students (Study 1), ethnic minority college students (Study 2) and lesbian and gay male adults (Study 3), we found strong support for the model. Results suggest that the process of exploring and understanding one\u27s minority identity can serve as an important basis for developing positive feelings toward and an enhanced sense of attachment to the group, which can in turn confer psychological benefits for minority individuals. Implications and directions for future research are discussed

Knowledge, attitudes and beliefs related to drugs among Pahang Matriculation students in Malaysia

Introduction Drug abuse has been a global threat not only in Malaysia but worldwide, especially among adolescents. This is alarming issue had been a serious public health problem worldwide. The aim of the study is to access the knowledge and attitude on drug abuse among Pahang Matriculation students in 2016. Methods A cross¬-sectional study was conducted involving 217 matriculation students. A self-determined questionnaire was distributed among the students regarding knowledge and attitude about drugs. Results The prevalence of good knowledge on drug abuse was (82.03%). The prevalence of students’ attitude on drug abuse has higher number of good attitude with the sum of 182 (83.9 %). Only gender showed a significant association with students’ knowledge (P= 0.046). Conclusion The knowledge, attitude, and practice of drug abuse among Pahang Matriculation students are good

The National Childrens Study: An Introduction and Historical Overview

The National Children’s Study (NCS) was an ambitious attempt to map children’s health and development in a large representative group of children in the United States. In this introduction, we briefly review the background of the NCS and the history of the multiple strategies that were tested to recruit women and children. Subsequent articles then detail the protocols and outcomes of 4 of the recruitment strategies. It is hoped that lessons learned from these attempts to define a study protocol that could achieve the initial aims of the NCS will inform future efforts to conceptualize and execute strategies to provide generalizable insights on the longitudinal health of our nation’s children

Overshadowing by fixed- and variable-duration stimuli

Two experiments investigated the effect of the temporal distribution form of a stimulus on its ability to produce an overshadowing effect. The overshadowing stimuli were either of the same duration on every trial, or of a variable duration drawn from an exponential distribution with the same mean duration as that of the fixed stimulus. Both experiments provided evidence that a variable-duration stimulus was less effective than a fixed-duration cue at overshadowing conditioning to a target conditioned stimulus (CS); moreover, this effect was independent of whether the overshadowed CS was fixed or variable. The findings presented here are consistent with the idea that the strength of the association between CS and unconditioned stimulus (US) is, in part, determined by the temporal distribution form of the CS. These results are discussed in terms of time-accumulation and trial-based theories of conditioning and timing

Study design and rationale for Optimal aNtiplatelet pharmacotherapy guided by bedSIDE genetic or functional TESTing in elective percutaneous coronary intervention patients (ONSIDE TEST): a prospective, open-label, randomised parallel-group multicentre trial (NCT01930773)

BACKGROUND AND AIM: High platelet reactivity (HPR) and presence of CYP2C19 loss-of-function alleles are associated with higher risk for periprocedural myocardial infarction in clopidogrel-treated patients undergoing percutaneous coronary intervention (PCI). It is unknown whether personalised treatment based on platelet function testing or genotyping can prevent such complications. METHODS: The ONSIDE-TEST is a multicentre, prospective, open-label, randomised controlled clinical trial aiming to assess if optimisation of antiplatelet therapy based on either phenotyping or genotyping is superior to conventional care. Patients will be randomised into phenotyping, genotyping, or control arms. In the phenotyping group, patients will be tested with the VerifyNow P2Y12 assay before PCI, and patients with a platelet reactivity unit greater than 208 will be switched over to prasugrel, while others will continue on clopidogrel therapy. In the genotyping group, carriers of the *2 loss-of-function allele will receive prasugrel for PCI, while wild-type subjects will be treated with clopidogrel. Patients in the control arm will be treated with standard-dose clopidogrel. The primary endpoint of the study is the prevalence of periprocedural myocardial injury within 24 h after PCI in the controls as compared to the phenotyping and genotyping group. Secondary endpoints include cardiac death, myocardial infarction, definite or probable stent thrombosis, or urgent repeat revascularisation within 30 days of PCI. Primary safety outcome is Bleeding Academic Research Consortium (BARC) type 3 and 5 bleeding during 30 days of PCI. SUMMARY: The ONSIDE TEST trial is expected to verify the clinical utility of an individualised antiplatelet strategy in preventing periprocedural myocardial injury by either phenotyping or genotyping

t-test using STATA software

Students-t test is the most popular statistical test. The test compares two mean values to judge if they are different or not. For small data it is possible to conduct it using manual calculation – however that is not the case. Researchers would need to use statistical software and packages to conduct their analysis. This guide will help the junior researchers to conduct independent- and paired-t test using STATA software

Inhibition of Mediodorsal Thalamus Disrupts Thalamofrontal Connectivity and Cognition

Cognitive deficits are central to schizophrenia but the underlying mechanisms still remain unclear. Imaging studies performed in patients point to decreased activity in the medio-dorsal thalamus (MD) and reduced functional connectivity between the MD and prefrontal cortex (PFC) as candidate mechanisms. However, a causal link is still missing. We used a pharmacogenetic approach in mice to diminish MD neuron activity and examined the behavioral and physiological consequences. We found that a subtle decrease in MD activity is sufficient to trigger selective impairments in prefrontal-dependent cognitive tasks. In vivo recordings in behaving animals revealed that MD-PFC beta-range synchrony is enhanced during acquisition and performance of a working memory task. Decreasing MD activity interfered with this task-dependent modulation of MD-PFC synchrony, which correlated with impaired working memory. These findings suggest that altered MD activity is sufficient to disrupt prefrontal-dependent cognitive behaviors, and could contribute to the cognitive symptoms observed in schizophrenia