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1.
Antonino Drago 《Science & Education》1994,3(2):189-198
Recently, some teachers have launched proposals for teaching physics by starting from thermodynamics rather than from mechanics. Such proposals are included in Mach's thesis, according to which thermodynamics is more basic for theoretical physics than mechanics. The past history of such a thesis is quickly sketched. Then, by recent results in theoretical physics, it is qualified in a new, modern version. As such it appears as an instance of a general conflict between two radically different ways to produce theoretical physics. The conflict results from two different options, about both the kind of mathematics and the kind of the organization of the theory. After such a general illustration of the great relevance of history of physics for physics teaching, the cultural bounds of such proposals are recognized and discussed. 相似文献
2.
Gail M. Dummer David H. Clarke Paul Vaccaro Lee Vander Velden Allan H. Goldfarb James M. Sockler 《Research quarterly for exercise and sport》2013,84(2):97-102
Abstract The purpose of this study was to examine age-related differences in muscular strength and muscular endurance among 73 female masters swimmers aged 24 to 71 years. Each subject was assessed on measures of body size, grip strength, peak isokinetic torque of shoulder and knee flexion and extension, and endurance of shoulder and knee movements. Although swim training appears to have resulted in higher strength values for these swimmers than for less active women, an age-related decline in muscular strength values was nevertheless apparent. The results fail to reveal a similar age-related trend for muscular endurance, suggesting that swim training influences muscular endurance more than muscular strength among adult women. 相似文献
3.
The seismic protection of objects contained within museums is a topic of great interest, especially with reference to how they are displayed or stored. This problem is the same as that of a large class of non-structural components, such as mechanical and electrical hospital and laboratory equipment that could lose their functionality because of earthquakes. Statues and ceramics simply supported on the floor represent a significant set of case. In some cases, like the Bronzes of Riace, isolation systems have been developed. However, in general museum exhibits are not equipped with devices capable of mitigating the oscillations induced by possible earthquakes. The case study of a marble statue placed on a freestanding squat rigid pedestal is examined. The system of algebraic differential equations governing the problem has been derived and included in an ad-hoc numerical procedure. It is shown that the insertion of a squat rigid body with low frictional resistance at the lower interface with the floor, and high frictional resistance at the upper interface with the artifact significantly reduces the amplitude of the rocking response. As a result the artifact rocks without sliding on the rigid base that slides without rocking with respect to the floor. The numerical analysis performed can be a tool to help in the choice of the optimal friction values in the surfaces of the flat block, designed as a simple isolation system. 相似文献
4.
目的:本研究集中探讨水平支座上独立放置简单叠合的双刚性块的动力学行为,旨在通过构建并求解合适的动力学数值模型以助于设计可广泛适用于博物馆、实验室和医院的保护小型艺术品或装置的隔振系统。创新点:1.研究对象为两个叠合在一起的刚性块,较以往同类问题中的单一刚性块,更具现实意义;2.同时研究了刚性块的摆动和滑动两类运动模式。方法:1.基于达朗贝尔原理构建摆动控制方程,分析单刚体情形下的摆动并利用数值手段描述其滑动状态;2.在分析单刚体的基础上构建双刚体控制方程组并对其进行数值求解。结论:1.通过研究大理石雕塑置于蹲式刚性基底上且基底独立放置在移动地面上的情形发现,相比于滑动,雕塑自身的摆动是造成其损坏的主要原因;2.在某些情况下,刚体表面延迟的存在可以避免细长刚性块的翻转,尤其是对于那些细长的摇摆块体以及上部块体质量增加的情形;3.本文提出的数值分析可以成为优化简易隔振系统的一个有效工具。 相似文献
5.
Adam Moore Victoria Kern Alexis Carlson Annemarie Vaccaro Jordan A. Abbott 《The Educational forum》2020,84(3):272-285
AbstractUsing grounded theory, we examined the ways in which undergraduate teacher candidates with disabilities developed a sense of purpose and constructed professional identities. Our findings suggest K-12 experiences with advocacy as well as exclusionary school experiences influenced their emerging professional identities. Resistance to a deficit view of disability was central to teachers’ professional identities and influenced their desire to become “change agents” in their future professions. We describe collegiate experiences that affirmed or presented roadblocks to their career path. 相似文献
6.
The purpose of this study was to examine African American toddlers' cortisol response to acute physical play activity within a full-time subsidized day care environment. Saliva samples were taken from participants (N = 22, ages 26–45.5 months) before and after physical play and control play conditions at the same time of day. ActiheartTM monitors were used to estimate the intensity of the play conditions. Although heart rate and other indicators were significantly higher during physical play, no change in cortisol levels was seen pre- to postphysical play. Further research is needed to better understand the cortisol response observed. 相似文献
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This paper analyzes the opportunities offered by information and communication technologies (ICTs) and the related ethical
issues, within the transparency practices of nongovernmental organizations (NGOs). Based upon a one-year study of a European
NGO, the Italian Association of Blind People, it presents compelling empirical evidence concerning the main ethical, social
and economic challenges that NGOs face in the development of more transparent relationships with the public and the related
role of ICTs, in particular, the organization’s website. This study shows that, although the attempt to be completely transparent
has great ethical value, ICT-enabled information disclosure is limited by privacy and security concerns and by pressure from
financial supporters and benefactors and potential NGO competitors who vie for grants and donations. The paper provides some
implications and suggestions for managers of NGOs and policy makers. 相似文献
9.
David H. Clarke Paul Vaccaro Nancy M. Andresen 《Research quarterly for exercise and sport》2013,84(4):318-322
Abstract Muscular and aerobic capacity changes resulting from three months of wrestling training were examined in a group of normally active 7- to 9-year-old boys (N = 23) who competed in an intramural league tournament. A nontraining group of twenty-two boys of similar age, height, and weight served as control subjects, and were studied during the same period of time. The subjects were measured for body dimensions and skinfolds, and were given measures of back lift, leg press, and arm endurance (dips and chins). They were also measured for [Vdot]E max, [Vdot]O 2 max, and HR max employing a progressive treadmill protocol. Results of ANCOVA analyses indicated that (1) the mean improvements in [Vdot]E max (2.93 1·min ?1 ) and in [Vdot]O 2 max (+ 6.6 ml·kg ?1 ·min ?1 ) were not significantly greater than control (p > .05), nor was HR max; (2) arm endurance improved significantly over control (p < .05), as did the leg press, but the back lift was not improved significantly (p > .05); (3) no significant change occurred in height, weight, or in some of skinfolds (p > .05), but the wrestlers were less endomorphic and more ectomorphic than their control counterparts, and were judged essentially equivalent in mesomorphy. It is concluded that wrestling training in young boys improves strength, but does not improve aerobic capacity more than one would expect to see in normal children of similar age and size. 相似文献
10.
In the nineteenth century, imported wallpapers covered interior walls of Persian palaces and mansions, of which Vasiq-Ansari House in Isfahan, Iran, exhibits very highly elaborated examples. In this study, micro-Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet–visible spectroscopy, and light microscopy were used to identify pigments and other materials used in the wallpapers of Vasiq-Ansari House. Results indicated that chrome yellow, artificial ultramarine blue, brass metallic leaf, an organic red dyestuff (probably cochineal), and a copper-based green were used as colourants in the wallpapers. Different shades of brown were achieved by mixing various combinations of red lead, carbon black, and calcium carbonate. The white calcium carbonate was also used as a ground layer, applied to a paper support composed of bast and softwood fibres. Based on knowledge of the materials used, these wallpapers are most probably manufactured from the mid- to late-nineteenth century. 相似文献