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141.
This paper describes the development of the Work Environment Scale, which includes measures of perceived stressful and supportive aspects of the job milieu. This scale is used to examine stressful effects of the work environment on personal functioning and the stress-buffering value of work and family social resources among a representative community group of men and women. Work stressors had a greater impact on men, but supportive social resources provided more attenuation of such effects among men than among women. Although work stressors generally had less effect on men whose wives were employed, high stress in the women's work settings had some indirect negative consequences for their husbands. Reprint requests should be directed to the authors, Social Ecology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, U.S.A. 相似文献
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143.
We conducted playback experiments to examine how parent tree swallows (Tachycineta bicolor) use nestling begging calls to distribute feedings to individuals within broods. In a first study, we used a paired-choice
test to determine if parents discriminated between the taped begging calls of nestlings deprived of food and those of nestlings
that had been recently fed. Our results showed that parents directed their first feeding attempt towards model nestlings near
speakers playing deprived calls significantly more often than to models near speakers playing fed calls. They also made more
feeding attempts overall to models with deprived calls. In the second study, we varied call rate and amplitude to examine
which call features parents might use to discriminate begging calls. Parents directed significantly more first feeding attempts
and more feeding attempts overall towards non-begging nestlings near speakers playing high call rates than to nestlings near
speakers playing low call rates. They did not, however, discriminate between calls differing in amplitude. Previous studies
have shown that parent birds use begging calls to regulate overall feeding rates to the brood. Our results suggest that parent
tree swallows also use begging calls when feeding individual nestlings and, in particular, prefer calls associated with increased
levels of nestling hunger.
Received: 14 February 2000 / Revised: 6 October 2000 / Accepted: 16 October 2000 相似文献
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NELUP was a five-year academic research project into interdisciplinary river catchment modelling. The experience of staff involved offers useful insights into the intellectual and practical problems associated with interdisciplinary catchment management research and the dissemination and acceptance of results. In particular, it is suggested that: entrenched academic territories, derived from disciplinary and data differences, make managing an interdisciplinary team of researchers a non-trivial task; data errors, model complexity and model generality masked by a seductively sophisticated-looking DSS risk an illusion of technique; and that acceptance of decision support is hindered by practitionersand policy makers' suspicion of potential automated decision making by default. 相似文献
147.
The UK is reportedly an international leader in the application of environmental policy appraisal (EPA). From the late 1980s until 2004, UK central government sought to produce ex ante assessments of the potential environmental impacts of different policy options. Critics maintain that EPA had a very limited impact on policy-making activities in Whitehall departments. However, the empirical basis for these claims is surprisingly thin. This paper seeks to better understand what facilitated or retarded EPA by looking at its use in Whitehall, with the aim being to draw lessons for the UK's new and more integrated appraisal regime, as well as similar systems in the European Union. The paper finds that the implementation of EPA was both weak and highly sectorised, and that there is an underlying resistance to policy appraisal per se in Whitehall. These weaknesses urgently need to be addressed otherwise new systems of integrated appraisal will not deliver what is expected of them. 相似文献
148.
Rosalind Aughwane Emma Ingram Edward D. Johnstone Laurent J. Salomon Anna L. David Andrew Melbourne 《黑龙江环境通报》2020,40(1):38-48
Objective
Magnetic resonance imaging (MRI) of placental invasion has been part of clinical practice for many years. The possibility of being better able to assess placental vascularization and function using MRI has multiple potential applications. This review summarises up-to-date research on placental function using different MRI modalities.Method
We discuss how combinations of these MRI techniques have much to contribute to fetal conditions amenable for therapy such as singletons at high risk for fetal growth restriction (FGR) and monochorionic twin pregnancies for planning surgery and counselling for selective growth restriction and transfusion conditions.Results
The whole placenta can easily be visualized on MRI, with a clear boundary against the amniotic fluid, and a less clear placental-uterine boundary. Contrasts such as diffusion weighted imaging, relaxometry, blood oxygenation level dependent MRI and flow and metabolite measurement by dynamic contrast enhanced MRI, arterial spin labeling, or spectroscopic techniques are contributing to our wider understanding of placental function.Conclusion
The future of placental MRI is exciting, with the increasing availability of multiple contrasts and new models that will boost the capability of MRI to measure oxygen saturation and placental exchange, enabling examination of placental function in complicated pregnancies. 相似文献149.
Karen L. Stals Matthew Wakeling Júlia Baptista Richard Caswell Andrew Parrish Julia Rankin Carolyn Tysoe Garan Jones Adam C. Gunning Hana Lango Allen Lisa Bradley Angela F. Brady Helena Carley Jenny Carmichael Bruce Castle Deirdre Cilliers Helen Cox Charu Deshpande Abhijit Dixit Jacqueline Eason Frances Elmslie Andrew E. Fry Alan Fryer Muriel Holder Tessa Homfray Emma Kivuva Victoria McKay Ruth Newbury-Ecob Michael Parker Ravi Savarirayan Claire Searle Nora Shannon Deborah Shears Sarah Smithson Ellen Thomas Peter D. Turnpenny Vinod Varghese Pradeep Vasudevan Emma Wakeling Emma L. Baple Sian Ellard 《黑龙江环境通报》2018,38(1):33-43
针对传统教与学算法在解决复杂多峰函数优化问题时,具有局部最优且搜索开发能力较差的缺点,提出了一种改进的多学习教与学优化算法,新算法为学员的每一维加入不同的教学因子,设计了基于学员均值比较的教师选择策略和向教师及学员学习的多学习策略。基于多个单峰和多峰函数的仿真结果表明,新算法跟传统的、改进的教与学算法相比,在稳定性、寻优精度和收敛速度方面更具优势。 相似文献