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51.
Reasoning about mechanisms is one of the hallmarks of disciplined inquiry in science and engineering, but comparatively little is known about its precursors and development. Children at grades 2 and 5 predicted and explained the motion of simple mechanical systems composed entirely of visible linkages (levers). Students' explanations of device behavior suggested four forms of knowledge: simple recognition of device components, noting of structural relations among components, construction of cause-effect rules derived by observation of regularities in device behavior, and identification of essential system components and interactions among components that accounted for cause–effect rules. Only a few children coordinated multiple essential components to constitute a mechanistic causal scheme. Mechanistic causal schemes, in turn, were associated with successful prediction of the output motion of a system. Device tracing via gesture and talk appeared to support this form of knowledge development, and hence may inform future instructional design.  相似文献   
52.
This study examined the contribution to parent‐adolescent conflict resolution of parental adult attachment styles and attitudes toward adolescent separation. Questionnaires were completed by 295 couples with early to late adolescent children. Structural equation models were used to test self and partner influences on conflict resolution for three attachment orientations: confidence (model A), anxiety (model B) and avoidance (model C). Model A showed self influences between parents' confidence orientation and negotiation and also via positive attitudes towards separation. Also, the fathers' use of negotiation was facilitated by the mothers' confidence orientation and vice versa, indicating partner influences as well. Model B showed self influences between parents' anxiety orientation and the use of dominance and withdrawal and also via negative attitudes towards separation. Model C showed self influences between parents' avoidance orientation and dominance and withdrawal, and a partner influence between fathers' avoidance and mothers' use of dominance. The results indicated that the parents' adult attachment system and the parenting system were related in the area of conflict resolution, and that self influences were stronger than partner influences.  相似文献   
53.
Body posture, mainly represented by horizontal bed rest, has been found to be associated with cortical inhibition, altered perceptual and cognitive processing. In the present research, the influence of Head Down Bed Rest (HDBR) – a condition also termed simulated microgravity – on emotional responses has been studied. Twenty-two male subjects were randomly assigned to either Sitting Control or HDBR group. After 3-h, subjects attended to a passive viewing emotional task in which 75 IAPS slides, divided into 25 pleasant, 25 neutral and 25 unpleasant, were presented in random order for 6 s each, while EEG was recorded from F7, F8 and Pz locations. Results showed in Sitting Controls the expected greater P300 and Late Positive Potential (LPP) to pleasant and unpleasant compared with neutral slides, an effect which indicates greater processing of emotional arousing stimuli. The HDBR group showed smaller non-significant differences among all emotional conditions in both ERP components. Arousal and valence subjective evaluations, typically less sensitive to experimental manipulation, did not differentiate groups. The observed ability of HDBR to inhibit cortical emotional responses raises an important issue on the risk that astronauts underestimate a dangerous/threatening situation or that long-term bedridden inpatients develop depressive symptoms.  相似文献   
54.
This article describes the influence of microstructure on the dielectric and piezoelectric properties of isovalent- donor- and acceptor-modified lead lanthanum zirconium titanate (PLZT) ceramics. The ceramic compositions, with formula: [Pb0.954La0.016Ba0.01Sr0.02][Zr0.525Ti0.475]0.981?( m /2)Nb0.012Zn m O3 where m =?0, 0.2, 0.4, 0.6, 0.8 and 1.0 mol% Zn, were synthesized via a solid-state reaction method. X-ray diffraction studies are supported by tolerance factor and electronegativity difference measurements. Scanning electron microscopy studies reveal grain growth enhancement with increase of Zn concentration. As the Zn concentration increased from 0 to 0.8 mol%, the room-temperature dielectric constant increased while the Curie temperature decreased continuously. An increase in the Zn content had the most significant effect on the piezoelectric properties. The optimum piezoelectric properties were observed for 1 mol% Zn composition.  相似文献   
55.
The dual-representation model of posttraumatic stress disorder (PTSD; Brewin, Gregory, Lipton, & Burgess, Psychological Review, 117, 210-232 2010) argues that intrusions occur when people fail to construct context-based representations during adverse experiences. The present study tested a specific prediction flowing from this model. In particular, we investigated whether the efficiency of temporal-lobe-based spatial configuration learning would account for individual differences in intrusive experiences and physiological reactivity in the laboratory. Participants (N = 82) completed the contextual cuing paradigm, which assesses spatial configuration learning that is believed to depend on associative encoding in the parahippocampus. They were then shown a trauma film. Afterward, startle responses were quantified during presentation of trauma reminder pictures versus unrelated neutral and emotional pictures. PTSD symptoms were recorded in the week following participation. Better configuration learning performance was associated with fewer perceptual intrusions, r = ?.33, p < .01, but was unrelated to physiological responses to trauma reminder images (ps > .46) and had no direct effect on intrusion-related distress and overall PTSD symptoms, rs > ?.12, ps > .29. However, configuration learning performance tended to be associated with reduced physiological responses to unrelated negative images, r = ?.20, p = .07. Thus, while spatial configuration learning appears to be unrelated to affective responding to trauma reminders, our overall findings support the idea that the context-based memory system helps to reduce intrusions.  相似文献   
56.
International students face social, psychological and academic challenges upon moving to a foreign country to pursue higher education. Clinical disciplines such as genetic counseling present additional challenges adapting to an unfamiliar health care system and different interactions and expectations with patients and colleagues. This study used semi-structured interviews to identify challenges that international genetic counseling students face during training in the United States. Eight international genetic counseling alumni who graduated from U.S.-accredited programs were interviewed. Participants stated that the U.S. academic system was unfamiliar—class participation and paper-writing required the greatest adjustment. There was a need for help in understanding social norms in academic settings. Clinically, they were unfamiliar with the dynamics and communication style of U.S. families. Non-native English speakers experienced greater difficulty in all areas. Most participants reported that they were uncomfortable asking for help in transitioning to life, study and work. Participants identified mentorship programs for international students as potentially useful in clarifying expectations in academic and clinical settings. These results may assist international students preparing to study genetic counseling in the U.S. and may help genetic counseling training programs identify the academic and clinical challenges faced by international students.  相似文献   
57.
Plans show shapes of objects from above, and represent both their left–right order and their order in the z-dimension (the distance of the objects). Elevations show only the vertical shapes of objects arranged from left to right. Plans, having more spatial information, may be more difficult for participants to construct. Results from a study with sighted, sighted-blindfolded, and early-blind participants on Piaget's perspective-taking three-mountain task support this hypothesis. The plan task was judged more difficult than the elevation task even when participants performed with the same level of accuracy on both tasks. In visual and tactile tasks, amount of spatial-order information may determine difficulty, rather than plan versus elevation per se.  相似文献   
58.
This study tests the relationship between pessimistic explanatory style and illness with questionnaire data. Questionnaires were administered to 234 college students at a mid‐sized Western university. Four variables were tested as potential mediators of the pessimistic explanatory style/illness relationship: symptoms of depression, perceived stress, social support, and poor health practices. Results indicated that only the global dimension of pessimistic explanatory style was related to experiences of illness, and hence was the only dimension that could be mediated by the proposed variables. Results demonstrated that symptoms of depression mediated the relationship between global attributions for negative events and illness. Exploratory analyses also suggest that stress is implicated in this process such that it increases symptoms of depression, which in turn influence illness.  相似文献   
59.
Roehling  Patricia V.  Bultman  Marta 《Sex roles》2002,46(9-10):279-293
Using a sample of 961 dual-earner couples, the authors examined the relationship between work-related travel and marital satisfaction, using gender role attitudes and parental status as moderators. For women and men with children, the impact of travel is generally consistent with gender role congruence theory, which posits that marital satisfaction will be highest when gender role attitudes and gender role behaviors are congruent. Generally, when one holds traditional gender role attitudes, marital satisfaction is stable or enhanced when the husband travels, and is lower when the wife travels. Nontraditional parents are generally less happy if either member travels. The results were less predictable among couples without children in the home.  相似文献   
60.
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