Random effects regression mixture models are a way to classify longitudinal data (or trajectories) having possibly varying lengths. The mixture structure of the traditional random effects regression mixture model arises through the distribution of the random regression coefficients, which is assumed to be a mixture of multivariate normals. An extension of this standard model is presented that accounts for various levels of heterogeneity among the trajectories, depending on their assumed error structure. A standard likelihood ratio test is presented for testing this error structure assumption. Full details of an expectation-conditional maximization algorithm for maximum likelihood estimation are also presented. This model is used to analyze data from an infant habituation experiment, where it is desirable to assess whether infants comprise different populations in terms of their habituation time. 相似文献
Colorism is a persistent problem for people of color in the USA. Colorism, or skin color stratification, is a process that privileges light-skinned people of color over dark in areas such as income, education, housing, and the marriage market. This essay describes the experiences of African Americans, Latinos, and Asian Americans with regard to skin color. Research demonstrates that light-skinned people have clear advantages in these areas, even when controlling for other background variables. However, dark-skinned people of color are typically regarded as more ethnically authentic or legitimate than light-skinned people. Colorism is directly related to the larger system of racism in the USA and around the world. The color complex is also exported around the globe, in part through US media images, and helps to sustain the multibillion-dollar skin bleaching and cosmetic surgery industries. 相似文献
Information presented concurrently and redundantly to 2 or more senses (intersensory redundancy) has been shown to recruit attention and promote perceptual learning of amodal stimulus properties in animal embryos and human infants. This study examined whether the facilitative effect of intersensory redundancy also extends to the domain of memory. We assessed bobwhite quail chicks' ability to remember and prefer an individual maternal call presented either unimodally or redundantly and synchronously with patterned light during the period prior to hatching. Embryos provided with unimodal auditory exposure failed to prefer the familiar call over a novel maternal call postnatally at 48 hr and 72 hr following exposure. In contrast, embryos provided with redundant, synchronous audiovisual stimulation significantly preferred the familiar call at 48 hr following exposure, but not at 72 hr. A second experiment provided chicks with a single 10‐min refamiliarization with the familiar call at either 48 hr or 72 hr following hatching. Chicks given only unimodal auditory exposure prior to hatching did not appear to benefit from this brief postnatal refamiliarization, showing no preference for the familiar call at either 72 or 96 hr. Chicks that received redundant audiovisual stimulation prenatally showed a significant preference for the familiar call (following the brief reexpo sure 24 hr earlier) at both 72 and 96 hr of age. These results are the first to demonstrate that redundantly specified information is remembered longer and reactivated more easily than the same information presented unimodally. These findings provide further evidence of the salience of intersensory redundancy in guiding selective attention and perceptual learning during early development. 相似文献
In many developing regions, women and young girls spend several hours daily in the collection of natural resources. Still the link between these household resource strategies and stakeholder perceptions of development priorities remains unexplored. This project examines this association with survey data representative of the adult population from Ghana’s Coastal Region. Although natural resource scarcity and the sustainability of resource use represent key development challenges, there are others (e.g., energy, sanitation, employment, and educational opportunities). As such, even in the face of natural resource scarcity, individuals may place greater importance on other dimensions of development, especially if household resource strategies are perceived as relatively efficient. The analytical focus here is on water and the results suggest that gender roles shape household water collection strategies, while also shaping these strategies’ perceived opportunity costs. Specifically, Ghanian adults more often see drinking water provision as their primary development need when water sources are distant and/or when male household members collect water (particularly male heads). In the end, I argue that social science inquiry benefits by contextualizing social dynamics within environmental context, particularly within cultural settings in which human subsistence is intimately tied to the state of the natural environment. 相似文献
This study focuses on levels of concern for hurricanes among individuals living along the Gulf Coast during the quiescent two‐year period following the exceptionally destructive 2005 hurricane season. A small study of risk perception and optimistic bias was conducted immediately following Hurricanes Katrina and Rita. Two years later, a follow‐up was done in which respondents were recontacted. This provided an opportunity to examine changes, and potential causal ordering, in risk perception and optimistic bias. The analysis uses 201 panel respondents who were matched across the two mail surveys. Measures included hurricane risk perception, optimistic bias for hurricane evacuation, past hurricane experience, and a small set of demographic variables (age, sex, income, and education). Paired t‐tests were used to compare scores across time. Hurricane risk perception declined and optimistic bias increased. Cross‐lagged correlations were used to test the potential causal ordering between risk perception and optimistic bias, with a weak effect suggesting the former affects the latter. Additional cross‐lagged analysis using structural equation modeling was used to look more closely at the components of optimistic bias (risk to self vs. risk to others). A significant and stronger potentially causal effect from risk perception to optimistic bias was found. Analysis of the experience and demographic variables’ effects on risk perception and optimistic bias, and their change, provided mixed results. The lessening of risk perception and increase in optimistic bias over the period of quiescence suggest that risk communicators and emergency managers should direct attention toward reversing these trends to increase disaster preparedness. 相似文献
This article explores masculinities and changes in men’s lives in the rural oil fields of Chad during the period of an oil and pipeline project described by the World Bank as a “model” for oil-as-development. In many parts of Africa, private sector investment is concentrated in the extractive industries, especially oil and gas projects. Africa’s emerging oil economies entail new institutional configurations, or what Michael Watts called an “oil complex,” that challenge antecedent norms and forms of identity. In this article, I describe the expectations, desires, and experiences of three distinct groups of men—those who found temporary employment on the project, those who continued to make a living from farming while contending with land expropriation, and those who migrated to oil field towns in search of work—to make three general points about the oil complex and masculinities in Chad. The structure of the global oil industry meant that local men who found jobs on the project could act as breadwinners and patriarchs, but only temporarily; local workers struggled post-employment with their exclusion from the possibilities associated with the project. Men who never found jobs continued to eke out a living from the land, but state-of-the-art policies governing land expropriation led simultaneously to conflict in families and greater economic interdependence among family members. Finally, in the low-media environment of the oil field region, ideas and images about sex, sexuality, and love emanating from the transient and hyper-masculine global oil industry workforce served as models for landless young men who migrated to oil field towns and who, in the absence of work, sought to transform themselves into objects of desire through the mediation of pharmaceuticals.
When working with clients in another language, having culturally relevant and properly translated clinic materials is vital to effective clinical practice. Not having them presents a barrier for bilingual therapists and their clients. This paper reviews common translation methods and introduces a multi‐level, community‐based approach for translating clinic materials for non‐English speaking clients. Informed by decolonizing practices, this five‐tier method includes members from the target community as cultural brokers to verify the accuracy and nuances of language for their cultural group, as well as a constant comparative method to ensure methodological rigor in the process of inclusion. We present community member's feedback and recommendations, as well as discuss advantages and challenges of using this collaborative culturally responsive translation method. 相似文献
Intercollegiate athletics represent an industry prone to challenges of work addiction and life balance. Work addiction and life balance domains in male and female intercollegiate athletic coaches and administrators (N = 245) were examined using multiple regression analysis. Higher levels of stress/anxiety, sleep disturbance, and career satisfaction and lower levels of quality of relationships and friendships were the strongest predictors of work addiction. Counseling focused on reducing the negative aspects of work addiction, while maintaining job performance, may benefit this population. 相似文献