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921.
Contingency perception is critical during infancy, providing the basis for the continuous learning (and re‐learning) of the relation between the developing body, self‐produced actions, and the environment. Nevertheless, relatively few studies have systematically examined the spatiotemporal parameters that optimize learning during development. Here, we present a series of experiments exploring a novel timing‐specific deficit in auditory learning in an animal model, the bobwhite quail (Colinus virginianus). In this paradigm, chicks vocalize to hear playback of an unfamiliar maternal call and are later tested for their filial preference for that call over a novel maternal call. Rather than a simple, hyperbolic decline in learning with increased delay between chick vocalization and playback, we found a window—450–900 msec after chicks ceased vocalizing—in which chicks appeared to have difficulty learning and forming a preference for the maternal call. This deficit nonetheless occurred only when the spatial location of call playback switched semi‐randomly during training, suggesting an attentional explanation for this deficit. Our findings indicate that optimization of the temporal parameters in operant paradigms with infants can be complex, particularly if tasks requiring the switching of attention between spatial locations. Our findings may thus be instructive for other developmental research with infants employing operant components. 相似文献
922.
Christopher Ojeda 《Social science quarterly》2015,96(5):1226-1243
923.
924.
Improving Risk Assessment Calculations for Traditional Foods Through Collaborative Research with First Nations Communities
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Claire McAuley Ave Dersch Lisa N. Kates Darryel R. Sowan Christopher A. Ollson 《Risk analysis》2016,36(12):2195-2207
As industrial development is increasing near northern Canadian communities, human health risk assessments (HHRA) are conducted to assess the predicted magnitude of impacts of chemical emissions on human health. One exposure pathway assessed for First Nations communities is the consumption of traditional plants, such as muskeg tea (Labrador tea) (Ledum/Rhododendron groenlandicum) and mint (Mentha arvensis). These plants are used to make tea and are not typically consumed in their raw form. Traditional practices were used to harvest muskeg tea leaves and mint leaves by two First Nations communities in northern Alberta, Canada. Under the direction of community elders, community youth collected and dried plants to make tea. Soil, plant, and tea decoction samples were analyzed for inorganic elements using inductively coupled plasma‐mass spectrometry. Concentrations of inorganic elements in the tea decoctions were orders of magnitude lower than in the vegetation (e.g., manganese 0.107 mg/L in tea, 753 mg/kg in leaves). For barium, the practice of assessing ingestion of raw vegetation would have resulted in a hazard quotient (HQ) greater than the benchmark of 0.2. Using measured tea concentrations it was determined that exposure would result in risk estimates orders of magnitude below the HQ benchmark of 0.2 (HQ = 0.0049 and 0.017 for muskeg and mint tea, respectively). An HHRA calculating exposure to tea vegetation through direct ingestion of the leaves may overestimate risk. The results emphasize that food preparation methods must be considered when conducting an HHRA. This study illustrates how collaboration between Western scientists and First Nations communities can add greater clarity to risk assessments. 相似文献
925.
926.
Complex trauma and mental health in children and adolescents placed in foster care: findings from the National Child Traumatic Stress Network 总被引:1,自引:0,他引:1
Greeson JK Briggs EC Kisiel CL Layne CM Ake GS Ko SJ Gerrity ET Steinberg AM Howard ML Pynoos RS Fairbank JA 《Child welfare》2011,90(6):91-108
Many children in the child welfare system (CWS) have histories of recurrent interpersonal trauma perpetrated by caregivers early in life often referred to as complex trauma. Children in the CWS also experience a diverse range of reactions across multiple areas of functioning that are associated with such exposure. Nevertheless, few CWSs routinely screen for trauma exposure and associated symptoms beyond an initial assessment of the precipitating event. This study examines trauma histories, including complex trauma exposure (physical abuse, sexual abuse, emotional abuse, neglect, domestic violence), posttraumatic stress, and behavioral and emotional problems of 2,251 youth (age 0 to 21; M = 9.5, SD = 4.3) in foster care who were referred to a National Child Traumatic Stress Network site for treatment. High prevalence rates of complex trauma exposure were observed: 70.4% of the sample reported at least two of the traumas that constitute complex trauma; 11.7% of the sample reported all 5 types. Compared to youth with other types of trauma, those with complex trauma histories had significantly higher rates of internalizing problems, posttraumatic stress, and clinical diagnoses, and differed on some demographic variables. Implications for child welfare practice and future research are discussed. 相似文献
927.
Donald J. Baumann Charles Grigsby Janess Sheets J. Christopher GrahamJason Holoubek James FarrisEugene Wang 《Children and youth services review》2011,33(9):1648-1657
This article presents a concept-guided approach to the assessment of risk in the life situations of children alleged to be maltreatment victims. This concept-guided risk assessment is theoretically based and is the first to use a nomological hierarchy which can yield itself to systematic testing for construct validity. Data were collected on 1199 cases referred for investigations of child maltreatment. Reliability was examined by applying Cronbach's alpha coefficient to the 25 risk features and the 18 risk category constructs within the seven risk areas. Convergent validity coefficients for seven risk area constructs and eighteen risk category constructs were computed and structural validity was examined using an analysis technique adapted from the multitrait-multimethod technique of Campbell and Fiske (1959). Predictive validity was assessed using a multivariate measure assessing rated risk, seriousness, and concern. In general, the results support construct validity. Improvements are needed in assessments of child vulnerability and caregiver stress. The overall psychometric evidence, combined with the model's hierarchical and theoretical nature, suggests a promising direction for future research on understanding and preventing child maltreatment. 相似文献
928.
To entice consumers to purchase both current and next generation products, many manufacturers and retailers offer trade‐in programs that allow buyers of the first generation product to trade‐in the product and purchase the new generation product at a lower price. By considering the interactions between “forward‐looking” consumers and a firm when a trade‐in program is offered, we analyze a two‐period dynamic game to determine the optimal prices of two successive‐generation products in equilibrium, and examine the conditions under which trade‐in programs are beneficial to the firm. Our model incorporates market heterogeneity (valuation of the first generation product varies among the consumer population), product uncertainty (the incremental value of the new product is uncertain before its introduction), and consumers' forward‐looking behavior (consumers take future product valuation and prices into consideration when making purchasing decisions). With the trade‐in option, we show that consumers are willing to pay a price that is higher than their valuations of the current product. Furthermore, trade‐in programs are more beneficial to the firm when: (i) the durability of the current product is high; (ii) the market heterogeneity is low; or (iii) the uncertainty level (or the expected incremental value) of the new product is high. Finally, when the incremental value of the new product is more uncertain, consumers are more willing to purchase the current product because of the “option” value of the trade‐in programs and thus trade‐in programs can be more beneficial to the firm in this case. 相似文献
929.
The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) is being revised. A proposed revision hotly debated is to remove what is known as the exclusionary criterion and allow clinicians to diagnose a person with a major depressive episode within the early days and weeks following a death. The Executive Committee of the Association for Death Education and Counseling (ADEC) commissioned its Scientific Advisory Committee (SAC) to examine the debate over removing the exclusionary criterion and provide a written report. The DSM-IV-TR classifies bereavement as a clinical condition that is not a mental disorder. The exclusionary criterion states that within the first 2 months of the onset of bereavement a person should not be diagnosed as having major depression unless certain symptoms not characteristic of a normal grief reaction are present. We note these symptoms when discussing the exclusionary criterion. In the report we identify the features that comprise the exclusionary criterion, examine reasons (including research conclusions and clinical concerns) given for retaining and for eliminating the exclusionary criterion, offer extensive comments from experienced licensed clinicians about the issues involved, discuss diagnostic and treatment implications, and offer specific recommendations for ADEC to implement. 相似文献
930.
In this article we conduct a textual analysis of memorial websites created by mothers who have experienced a loss due to sudden infant death syndrome (SIDS). Using an online Internet ethnographic approach, we reviewed a series of 20 sites in an attempt to analyze the motivations of the site creators as manifested in their online projects. We spent time on the sites, moving through all facets of them, following links, and experiencing them the way a visitor would encounter them. In this virtual exploration we uncovered personal narratives, community building, religious imagery, and numerous examples of social networking. We also analyzed guest books in order to understand who visits these sites and their reasons for doing so. We conclude that development of these sites are a process that helps some mothers in their grief and gives them a focus and activity that is helpful and perhaps healing. More importantly perhaps is the potential for community building and networking that this type of activity allows. As an extension of a real-world memorial such as a gravesite, a virtual mourning space provides more in the way of these types of communications. Our work suggests that memorial websites constructed by SIDS parents help in meaning and identity reconstruction after loss. 相似文献