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71.
Several indices of sexual behavior were characterized for male rats of the Lewis (LEW), Sprague-Dawley (SD) and Fischer (F344)
strains. Males were permitted access to a receptive female of their own strain for five 50-min sessions every fifth day. LEW
males emitted longer latencies (first mount, intromission, ejaculation and post-ejaculatory interval) and lower frequencies
(mounts, intromissions, ejaculations, intromission ratio) relative to F344 males, with the SD strain in general, lying intermediate.
Following this assessment, males of each strain were randomly assigned to females of their own or another strain to ascertain
whether differences were due to differential female receptivity. Although there were no significant differences during this
phase indicative of differential receptivity, the sample size may preclude a definitive interpretation of such results. The
data were discussed in the context of other behavioral differences between the strains and the possible neurobiological mechanisms
underlying these differences. 相似文献
72.
Mental Rotation With Tangible Three‐Dimensional Objects: A New Measure Sensitive to Developmental Differences in 4‐ to 8‐Year‐Old Children 下载免费PDF全文
Zachary Hawes Jo‐Anne LeFevre Chang Xu Catherine D. Bruce 《Mind, Brain, and Education》2015,9(1):10-18
There is an emerging consensus that spatial thinking is fundamental to later success in math and science. The goals of this study were to design and evaluate a novel test of three‐dimensional (3D) mental rotation for 4‐ to 8‐year‐old children (N = 165) that uses tangible 3D objects. Results revealed that the measure was both valid and reliable and indicated steady growth in 3D mental rotation between the ages of 4 and 8. Performance on the measure was highly related to success on a measure of two‐dimensional (2D) mental rotation, even after controlling for executive functioning. Although children as young as 5 years old performed above chance, 3D mental rotation appears to be a difficult skill for most children under the age of 7, as indicated by frequent guessing and difficulty with mirror objects. The test is a useful new tool for studying the development of 3D mental rotation in young children. 相似文献
73.
The ability to pump and manipulate fluid at the micron-scale is a basic requirement for microfluidic platforms. Many current manipulation methods, however, require expensive and bulky external supporting equipment, which are not typically compatible for portable applications. We have developed a contactless metal electro-osmotic micropump capable of pumping conductive buffers. The pump operates using two pairs of gallium metal electrodes, which are activated using an external voltage source and separated from a main flow channel by a thin micron-scale polydimethylsiloxane (PDMS) membrane. The thin contactless membrane allows for field penetration and electro-osmotic flow within the microchannel, but eliminates electrode damage and sample contamination commonly associated with traditional DC electro-osmotic pumps that utilize electrodes in direct contact with the working fluid. Our previous work has demonstrated the effectiveness of this method in pumping deionized water. However, due to the high resistivity of PDMS, this method proved difficult to apply towards manipulating conductive buffers. To overcome this limitation, we fabricated conductive carbon black (CB) powder directly into the contactless PDMS membranes. The increased electrical conductivity of the contactless PDMS membrane significantly increased micropump performance. Using a microfluidic T-channel device and an electro-osmotic flow model, we determined the influence that CB has on pump pressure for CB weight percents varying between 0 and 20. The results demonstrate that the CB increases pump pressure by two orders of magnitude and enables effective operations with conductive buffers. 相似文献
74.
This paper develops a framework for analyzing the competitive implications of innovation. The framework is based on the concept of transilience — the capacity of an innovation to influence the established systems of production and marketing. Application of the concept results in a categorization of innovation into four types. Examples from the technical history of the US auto industry are used to illustrate the concepts and their applicability. The analysis shows that the categories of innovation are closely linked to different patterns of evolution and to different managerial environments. Special emphasis is placed on the role of incremental technical change in shaping competition and on the possibilities for a technology based reversal in the process of industrial maturity. 相似文献
75.
Zachary K. Collier 《Structural equation modeling》2017,24(6):819-830
In this article, 3-step methods to include predictors and distal outcomes in commonly used mixture models are evaluated. Two Monte Carlo simulation studies were conducted to compare the pseudo class (PC), Vermunt’s (2010), and the Lanza, Tan, and Bray (LTB) 3-step approaches with respect to bias of parameter estimates in latent class analysis (LCA) and latent profile analysis (LPA) models with auxiliary variables. For coefficients of predictors of class membership, results indicated that Vermunt’s method yielded more accurate estimates for LCA and LPA compared to the PC method. With distal outcomes of latent classes and latent profiles, the LTB method produced the lowest relative bias of coefficient estimates and Type I error rates close to nominal levels. 相似文献
76.
Expressing sexuality is part of the human experience, yet sexual health is often ignored in regard to persons with disabilities. Individuals with disabilities are at risk of sexual abuse and exploitation, unwanted pregnancies, and sexually transmitted diseases. Additionally, many adolescents with disabilities lack the knowledge needed to develop a healthy sexual identity, therefore, increasing their vulnerability (Baladerian, et al., 2013; Boehning, 2006; Preston, 2013; SEICUS, 2012, 2014). Resources have been developed to improve the sexual health of individuals with disabilities; however, those who need this education may not have access to the resources. The purpose of this literature review is to examine sexual health education for individuals with disabilities; it focuses on risks to people with disabilities, current barriers to education, and available resources. 相似文献
77.
This article explores policy factors that may have systematically influenced the innovative vitality of the U.S. consumer electronics industry during the post World War II period. A series of successful innovations in electronic equipment that have become the foundation of international rivalry in this industry are examined with a focus on the several factors that might explain the relatively sluggish performance of U.S. firms in comparison with counterparts from Japan and elsewhere. The article suggests that the institutional climate for innovation, pertaining to considerations that are internal to the firm like management attitudes, practices and conventions, are predominantly important in explaining the innovative behavior of the industry. These tend to dominate the more frequently cited external or macroeconomic factors like inflation, industry structure, government regulation, the propensities to save and invest, etc.A great potential for improving economic progress lies in opportunities in research and education to provide a better basis for top executives to understand the key role of technology in management and corporate strategy. 相似文献
78.
Steven Obst Luke Heales Zachary Hrelja Prashneveet Ishri Johanna Wesche Lee Barber 《Journal of sports sciences》2019,37(16):1874-1883
This study examined the effect of diamond deloading tape on medial gastrocnemius (MG) muscle behaviour during exercise in healthy adults (n = 27). A randomised cross-over trial assessed the effect of tape (no-tape, sham-tape and deload-tape) on ankle and MG fascicle kinematics during three heel raise-lower exercises [double leg (DL), single leg (SL) and loaded single leg (LSL)]. There was no effect of tape on standing fascicle length (FL) or pennation angle (PA), or ankle or knee joint angle. There was a significant effect of tape on ankle kinematics for all exercises. Both the deload-tape and sham-tape resulted in less ankle plantar flexion but had no effect on dorsiflexion. There was a significant effect of tape on FL change for the SL and LSL exercise. Compared to no-tape, the deload-tape resulted in less fascicle shortening during ankle plantar flexion, and more fascicle lengthening during ankle dorsiflexion. For the LSL exercise, deload-tape caused MG fascicles to operate at longer lengths, for a given joint angle. Diamond taping, with or without added tension, has only a small effect on ankle and MG fascicle kinematics during the heel raise-lower exercise. With the exception of the LSL exercise, both tape conditions resulted in similar changes in the FL-angle relations. 相似文献
79.
Jennifer J. Hurley Andrea Medici Emily Stewart Zachary Cohen 《Multicultural Perspectives》2013,15(3):160-166
According to the United Nations High Commission for Refugees, the number of refugees worldwide was 10.5 million in 2009 and this number continues to grow (United Nations Refugee Agency, 2010). There is a shortage of evidence based practices and information regarding the state of service provision for young refugee children and their families in preschool programs. In this qualitative study, 25 early childhood educators participated in semi-structured interviews to illuminate the experiences of teachers as they work with preschool children and families in a small New England refugee resettlement community. Themes identified were barriers and facilitators related to two main categories of communication issues and cultural complexities. Implications for future research, teacher preparation programs, professional development and early childhood programs are discussed. 相似文献
80.