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71.
What Causes Specific Language Impairment in Children?   总被引:2,自引:0,他引:2  
ABSTRACT— Specific language impairment (SLI) is diagnosed when a child's language development is deficient for no obvious reason. For many years, there was a tendency to assume that SLI was caused by factors such as poor parenting, subtle brain damage around the time of birth, or transient hearing loss. Subsequently it became clear that these factors were far less important than genes in determining risk for SLI. A quest to find "the gene for SLI" was undertaken, but it soon became apparent that no single cause could account for all cases. Furthermore, although fascinating cases of SLI caused by a single mutation have been discovered, in most children the disorder has a more complex basis, with several genetic and environmental risk factors interacting. The clearest evidence for genetic effects has come from studies that diagnosed SLI using theoretically motivated measures of underlying cognitive deficits rather than conventional clinical criteria.  相似文献   
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One particular aspect of the literature on preferences for female body shapes has focused on the purported universality of preferences for a low waist‐to‐hip ratio (WHR), despite substantial evidence of cross‐cultural variability in such preferences. In the present study, we examined the effects of manipulating women's profile WHR, breast size, and ethnicity on men's ratings of physical attractiveness and health. A total of 51 African men in South Africa, 56 British Africans, and 114 British Caucasians rated 12 line drawings that varied in two levels of ethnicity, three levels of WHR, and two levels of breast size. Overall, the results suggested that there were cross‐cultural differences in preferred body shape, with the preferred body configuration varying as a function of the ethnicity of the figure being rated. In addition, there was a strong positive correlation between ratings of attractiveness and health. These findings are discussed in relation to the interplay between culture and evolution in determining ideals of attractiveness.  相似文献   
74.
Long-term potentiation (LTP) is typically studied using either continuous high-frequency stimulation or theta burst stimulation. Previous studies emphasized the physiological relevance of theta frequency; however, synchronized hippocampal activity occurs over a broader frequency range. We therefore tested burst stimulation at intervals from 100 msec to 20 sec (10 Hz to 0.05 Hz). LTP at Schaffer collateral–CA1 synapses was obtained at intervals from 100 msec to 5 sec, with maximal LTP at 350–500 msec (2–3 Hz, delta frequency). In addition, a short-duration potentiation was present over the entire range of burst intervals. We found that N-methyl-d-aspartic acid (NMDA) receptors were more important for LTP induction by burst stimulation, but L-type calcium channels were more important for LTP induction by continuous high-frequency stimulation. NMDA receptors were even more critical for short-duration potentiation than they were for LTP. We also compared repeated burst stimulation with a single primed burst. In contrast to results from repeated burst stimulation, primed burst potentiation was greater when a 200-msec interval (theta frequency) was used, and a 500-msec interval was ineffective. Whole-cell recordings of postsynaptic membrane potential during burst stimulation revealed two factors that may determine the interval dependence of LTP. First, excitatory postsynaptic potentials facilitated across bursts at 500-msec intervals but not 200-msec or 1-sec intervals. Second, synaptic inhibition was suppressed by burst stimulation at intervals between 200 msec and 1 sec. Our data show that CA1 synapses are more broadly tuned for potentiation than previously appreciated.Long-term potentiation (LTP) is used as a model for studying synaptic events during learning and memory (Bliss and Collingridge 1993; Morris 2003; Lynch 2004). At most synapses, LTP is triggered by postsynaptic Ca2+ influx through N-methyl-d-aspartic acid (NMDA) glutamate receptors (Collingridge et al. 1983; Harris et al. 1984; Herron et al. 1986) and, under some conditions, through L-type voltage-gated Ca2+ channels (Grover and Teyler 1990, 1994; Morgan and Teyler 1999). LTP was discovered in the dentate gyrus (Bliss and Lomo 1973) following several seconds of 10–100 Hz stimulation of the perforant path. Since then, many LTP studies have used similar long, high-frequency stimulation (HFS) protocols, most typically 100 Hz, 1 sec (Bliss and Collingridge 1993). Although effective, HFS does not resemble physiological patterns of activity (Albensi et al. 2007). Patterned stimulation resembling physiological activity, in particular theta burst stimulation, is also effective for LTP induction (Larson et al. 1986; Staubli and Lynch 1987; Capocchi et al. 1992; Nguyen and Kandel 1997). Theta burst stimulation consists of short bursts (4–5 stimuli at 100 Hz) repeated at 5 Hz, which lies within the hippocampal theta frequency range (4–12 Hz) (Bland 1986; Buzsáki 2002). Primed burst stimulation, another form of patterned stimulation, involves delivery of a priming stimulus followed by a single short burst (Larson and Lynch 1986; Rose and Dunwiddie 1986). The temporal requirements for primed burst LTP are quite precise (Diamond et al. 1988; Greenstein et al. 1988; Larson and Lynch 1989): Intervals less than 140 msec or greater than 200 msec are ineffective.The mechanisms underlying theta frequency-dependent LTP have been studied primarily using the primed burst protocol (Larson and Lynch 1986, 1988, 1989; Pacelli et al. 1989; Davies and Collingridge 1996). Activation of GABAB autoreceptors during the priming stimulus suppresses GABA release during the following burst (Davies et al. 1990; Lambert and Wilson 1994; Olpe et al. 1994), allowing greater postsynaptic depolarization (Larson and Lynch 1986; Pacelli et al. 1989) and more effective NMDA receptor activation (Davies and Collingridge 1996). Consequently, temporal requirements for primed burst potentiation match the time course of GABAB autoreceptor-mediated suppression of GABA release (Davies et al. 1990; Davies and Collingridge 1993; Mott et al. 1993).Besides theta, hippocampal activity is observed at other frequencies, notably sharp waves (0.01–5 Hz) (Buzsáki 1986, 1989; Suzuki and Smith 1987) and low-frequency oscillations (≤1 Hz) (Wolansky et al. 2006; Moroni et al. 2007). These lower frequencies dominate during slow wave sleep (Buzsáki 1986; Suzuki and Smith 1987; Wolansky et al. 2006; Moroni et al. 2007), and contribute to hippocampal memory processing (Buzsáki 1989; Pennartz et al. 2002). While synchronized population activity over frequencies from <1 Hz to 12 Hz is associated with hippocampal memory function, previous LTP studies have focused on theta. We therefore investigated burst stimulation at frequencies from 0.05 Hz to 10 Hz. We found that CA1 synapses potentiate to some degree over this entire range and that maximal potentiation occurs around delta frequency rather than theta.  相似文献   
75.
Bullying experiences and male sexual violence (SV) perpetration are major public health problems, and while extant literature suggests that they may share some developmental correlates, there is no established empirical link between being a perpetrator or victim of bullying and SV perpetration in the literature. Nonetheless, some SV prevention programs in the U.S. include bullying prevention components for elementary and middle-school aged children. Research is needed to test the hypothesized links between bullying experiences and SV perpetration to determine whether bullying prevention programs are likely to prevent SV perpetration. The purpose of this paper is to present results from a review of research on each of these topics and to discuss the potential shared and unique risk and protective factors within a social-ecological framework. The paper concludes with suggested directions for future research.  相似文献   
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Skin cancer is increasing, and prevention programs are essential. This study evaluated the impact of a skin cancer prevention program on sun-protection habits and swimming pool environments. The intervention included staff training; sun-safety lessons; interactive activities; providing sunscreen, shade, and signage; and promoting sun-safe environments. A randomized trial at 28 swimming pools in Hawaii and Massachusetts tested the efficacy of this program (Pool Cool) compared with an attention-matched injury-prevention control program. Results showed significant positive changes in children's use of sunscreen and shade, overall sun-protection habits, and number of sunburns and improvements in parents' hat use, sun-protection habits, and reported sun-protection policies and environments. Observations corroborated the positive findings. Pool Cool had significant positive effects at swimming pools in diverse audiences.  相似文献   
78.
Analytic group psychotherapy offers the potential for developing ego functions and enhancing identity formation. The nature of the interaction in group psychotherapy forces participants to deal with their perception of reality and revise their perceptions. After a brief review of the literature, focusing on the theoretical basis and ego development in analytic group psychotherapy, the paper discusses the following ego functions and gives an example of each: adaptation to reality, judgment, drive control, object relations (relationships with others), thought process and communication, defenses, affect differentiation, autonomy, mastery-competence, regulation of self-esteem, and frustration tolerance. The paper concludes with an example of assessing ego functions from a clinical vignette taken from one group psychotherapy session.  相似文献   
79.
As part of an international study of ethics and genetics, we present a comparison between survey responses of 43 East German and 212 West German geneticists to anonymous questionnaires. Both groups indicated that the experience of the Third Reich has impacted the genetics profession in Germany today. East German geneticists reported more directive counseling practices after prenatal diagnosis for 10 of 26 conditions than those from West Germany. When asked to give their personal opinions about pregnancy termination, East Germans were more accepting of abortion than their West German colleagues for 7 of 24 fetal indications. In addition, there were significant differences between the two sample groups for 8 questions on the perception of disability and society. Discussions with German geneticists suggest that, while both groups were affected by Germany's experience of Nazism, different abortion laws, political systems, and ideas about the doctor-patient relationship in former East and West Germany may account for discrepancies in reported genetic counseling practices and in attitudes toward abortion and disability.  相似文献   
80.
An adaptation of the Stroop color-naming task was used to investigate selective information processing related to eating behavior in 90 undergraduate women. This study differed from previous studies by (a) treating eating behavior as a continuous variable and (b) looking at five separate categories of words including color, neutral, food, body shape, and other emotionally salient words. We did not find a strong pattern of relation between the Stroop task and eating and body image measures. Results suggest that in a nonclinical population, direct methods of accessing cognitions related to eating may be more fruitful than indirect measures.  相似文献   
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