942 research outputs found
Overcoming camera instability problem for detecting and tracking moving objects in video using reduced data
Moving objects detection is a vital field of study in various applications. Many of such applications may have to capture and process a lot of data, then such these data need to be reduced as much as possible in order to have a reasonable and suitable system for achieving the desired aims efficiently. The proposed algorithm utilizes singular value decomposition (SVD) and Bayer pattern filter for their good properties in producing very representative reduced data. This data is then handled by frame difference objects detection, which in turn is an approach that doesn’t need to handle much data. The camera shaking which can be caused by a windy weather in the case of the outdoor static camera may introduce a frame difference with imprecise moving objects detection, hence frames compensation is conducted utilizing a transformation based on speed up robust feature transform (SURF) detected key points
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
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
Depression and Sexual Orientation During Young Adulthood: Diversity Among Sexual Minority Subgroups and the Role of Gender Nonconformity.
Sexual minority individuals are at an elevated risk for depression compared to their heterosexual counterparts, yet less is known about how depression status varies across sexual minority subgroups (i.e., mostly heterosexuals, bisexuals, and lesbians and gay men). Moreover, studies on the role of young adult gender nonconformity in the relation between sexual orientation and depression are scarce and have yielded mixed findings. The current study examined the disparities between sexual minorities and heterosexuals during young adulthood in concurrent depression near the beginning of young adulthood and prospective depression 6 years later, paying attention to the diversity within sexual minority subgroups and the role of gender nonconformity. Drawn from the National Longitudinal Study of Adolescent Health (N = 9421), we found that after accounting for demographics, sampling weight, and sampling design, self-identified mostly heterosexual and bisexual young adults, but not lesbians and gay men, reported significantly higher concurrent depression compared to heterosexuals; moreover, only mostly heterosexual young adults were more depressed than heterosexuals 6 years later. Furthermore, while young adult gender nonconforming behavior was associated with more concurrent depression regardless of sexual orientation, its negative impact on mental health decreased over time. Surprisingly, previous gender nonconformity predicted decreased prospective depression among lesbians and gay men whereas, among heterosexual individuals, increased gender nonconformity was not associated with prospective depression. Together, the results suggested the importance of investigating diversity and the influence of young adult gender nonconformity in future research on the mental health of sexual minorities.The authors acknowledge support for this research: the University of Arizona Norton School of Family and Consumer Sciences Fitch Nesbitt Endowment and a University of Arizona Graduate Access Fellowship to the second author. This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://www.cpc.unc.edu/addhealth). No direct support was received from grant P01-HD31921 for this analysis. The authors thank Noel Card and Susan Stryker for comments on the previous versions of this article and Richard Lippa and Katerina Sinclair for methodological and statistical consult. The authors also thank the anonymous reviewers and the Editor for their helpful comments.This is the accepted manuscript of a paper published in Archives of Sexual Behavior (Li G, Pollitt AM, Russell ST, Archives of Sexual Behavior 2015, doi:10.1007/s10508-015-0515-3). The final version is available at http://dx.doi.org/10.1007/s10508-015-0515-3
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
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A Rescorla-Wagner Drift-Diffusion Model of Conditioning and Timing
Computational models of classical conditioning have made significant contributions to the theoretic understanding of associative learning, yet they still struggle when the temporal aspects of conditioning are taken into account. Interval timing models have contributed a rich variety of time representations and provided accurate predictions for the timing of responses, but they usually have little to say about associative learning. In this article we present a unified model of conditioning and timing that is based on the influential Rescorla-Wagner conditioning model and the more recently developed Timing Drift-Diffusion model. We test the model by simulating 10 experimental phenomena and show that it can provide an adequate account for 8, and a partial account for the other 2. We argue that the model can account for more phenomena in the chosen set than these other similar in scope models: CSC-TD, MS-TD, Learning to Time and Modular Theory. A comparison and analysis of the mechanisms in these models is provided, with a focus on the types of time representation and associative learning rule used
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
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