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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 
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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.
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
75.
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
76.
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
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Prevalence of mindfulness literature and intervention in school psychology journals from 2006 to 2016 下载免费PDF全文
下载免费PDF全文 Stacy L. Bender Rachel Roth Alicia Zielenski Zachary Longo Ashley Chermak 《Psychology in the schools》2018,55(6):680-692
Mindfulness has been gaining momentum in the field of school psychology, however compared to other applied psychology fields, less research on mindfulness interventions has been conducted. This study systematically reviewed mindfulness literature and empirical studies in nine school psychology journals from 2006–2016. The prevalence of mindfulness articles and research specifically focused on mindfulness intervention were examined. Additionally, the type of intervention implemented, tier of intervention, and targets of intervention were examined. Results indicated that .57% of articles during the ten‐year time frame were related to mindfulness (n = 17). Eight of the 17 articles investigated mindfulness interventions, with interventions ranging from informal practices (e.g., Mandala coloring) to specific intervention programs (e.g., Compassion and Attention in the Schools). Majority of interventions were implemented at the universal level for students. Future directions for mindfulness research and the importance of mindfulness in school psychology are discussed. 相似文献
80.
K. Andrew R. Richards Jennifer M. Jacobs Zachary Wahl-Alexander James D. Ressler 《Journal of Adventure Education & Outdoor Learning》2018,18(4):367-381
Outdoor education (OE) has an increased presence in physical education as it addresses the discipline’s national standards and promotes involvement lifetime physical activity. However, physical educators’ learning to teach OE is not well documented. The purpose of this study was to understand preservice physical educators’ experiences in and perspectives on an OE field experience. Participants included 13 third-year preservice physical educators (10 male, 3 female). Qualitative data were collected using focus group interviews, observations and guided reflections. Results indicated that preservice teachers (PSTs) perceived a controlling course environment that limited educational outcomes. They did, however, increase in confidence teaching OE, and applied skills learned in the teacher education program. With the exception of learning to be more adaptable, however, the PSTs did not perceive the experience as relevant to future teaching. Results are discussed within the framework of occupational socialization theory, and implications for practice are noted. 相似文献