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61.
The cadence that maximises power output developed at the crank by an individual cyclist is conventionally determined using a laboratory test. The purpose of this study was two-fold: (i) to show that such a cadence, which we call the optimal cadence, can be determined using power output, heart-rate, and cadence measured in the field and (ii) to describe methodology to do so. For an individual cyclist's sessions, power output is related to cadence and the elicited heart-rate using a non-linear regression model. Optimal cadences are found for two riders (83 and 70 revolutions per minute, respectively); these cadences are similar to the riders’ preferred cadences (82–92?rpm and 65–75?rpm). Power output reduces by approximately 6% for cadences 20?rpm above or below optimum. Our methodology can be used by a rider to determine an optimal cadence without laboratory testing intervention: the rider will need to collect power output, heart-rate, and cadence measurements from training and racing sessions over an extended period (>6 months); ride at a range of cadences within those sessions; and calculate his/her optimal cadence using the methodology described or a software tool that implements it.  相似文献   
62.
Purpose: The present study aimed to determine if autonomic cardiac modulation was influenced by acute exposure to normobaric hypoxia. Method: Ten healthy male lowland dwellers completed five block-randomised single-blinded, crossed-over acute exposures to a normobaric hypoxic environment, each separated by 24 hours’ recovery (20.3%, 17.4%, 14.5%, 12.0% and 9.8% FIO2). Supine recordings were made of arterial oxygen saturation and electrocardiogram (ECG). RR intervals from the ECG trace were analysed for time (SDNN, lnrMSSD), frequency (lnVLF, lnLF, lnHF, lnTP, LFnu, and HFnu), and nonlinear (DFA-α1 and SampEn) heart rate variability components. Results: A significant reduction in arterial SaO2 occurred with reduced FIO2, along with a rise in heart rate (Cohen’s d?=?1.16, 95% Confidence Interval [2.64–6.46]), significant at 9.8% FIO2. A decrease in autonomic cardiac modulation was also found as shown by a statistically significant (at 9.8% FIO2) decrease in lnTP (d?=?1.84 [1.74–1.94]), and SampEn (d?=?0.98 [0.83–1.12]) and an increase in DFA-α1 (d?=?0.72 [0.60–0.84]) from normoxia at 9.8% FIO2. Conclusion: The decrease in variability indicated a reduction in autonomic cardiac modulation. There appears to be a threshold ~9.8% FIO2 (~6000?m equiv.), below which significant alterations in autonomic control occur.  相似文献   
63.

Objective

The purpose of this study was to investigate the relative effectiveness of three web-scale discovery (WSD) tools in answering health sciences search queries.

Methods

Simple keyword searches, based on topics from six health sciences disciplines, were run at multiple real-world implementations of EBSCO Discovery Service (EDS), Ex Libris''s Primo, and ProQuest''s Summon. Each WSD tool was evaluated in its ability to retrieve relevant results and in its coverage of MEDLINE content.

Results

All WSD tools returned between 50%–60% relevant results. Primo returned a higher number of duplicate results than the other 2 WSD products. Summon results were more relevant when search terms were automatically mapped to controlled vocabulary. EDS indexed the largest number of MEDLINE citations, followed closely by Summon. Additionally, keyword searches in all 3 WSD tools retrieved relevant material that was not found with precision (Medical Subject Headings) searches in MEDLINE.

Conclusions

None of the 3 WSD products studied was overwhelmingly more effective in returning relevant results. While difficult to place the figure of 50%–60% relevance in context, it implies a strong likelihood that the average user would be able to find satisfactory sources on the first page of search results using a rudimentary keyword search. The discovery of additional relevant material beyond that retrieved from MEDLINE indicates WSD tools'' value as a supplement to traditional resources for health sciences researchers.  相似文献   
64.
The topic of childhood vaccinations has received much news media attention recently, prompting scholars to examine how the public has responded. In light of this news, and the deep divide that seems to exist between parents who support childhood vaccinations and those who do not, this study examines how and why individuals may involve themselves in communication about vaccinations, particularly on social media or in other online environments. Focusing on the concept of communicative action and drawing from spiral of silence and other research, a survey of mothers (= 455) found that those who do not support childhood vaccinations are more likely to engage in communication about the issue, including information seeking, attending, forefending, permitting, forwarding, and sharing. In addition, issue importance and affective and cognitive involvement help drive communicative action regarding childhood vaccinations, which could affect public opinion or public perceptions of the issue. Theoretical and practical implications are discussed.  相似文献   
65.
贾庆文 《海外英语》2006,(12):34-35
当我四岁时,我把父母的胡桃木梳妆台上咬上牙印。他们没有看到我做这件事,但一次被发现了,他们并没有责备我。相反,40年来母亲充满深情地将牙印上的灰尘擦去。当我长大后,我问她为什么她从不将梳妆台的表面整修一下,她说,“我只是不想这样做。”直到我自己有了孩子我才能够完全理解这种情感。回忆孩子小时候的事情是人生最开心的事情之一。我的长子阿利屋夏如今20岁了,在外面上大学,但他少年时代的生活印记在我们房子里外到处都是。当他长大以后,我完成了使他长到门框边框的职责。偶尔我让他在靠着门框站立,测量他的身高,然后让他蹲到我们当…  相似文献   
66.
67.
This study examines sources of satisfaction, indicators of stress, academic performance, and reward structure in the academic careers of male and female faculty at a major midwestern state university. Faculty pairs were selected from five academic divisions. A total of 58 matched pairs were identified. Of these, 63 faculty responded, yielding data for 23 matched pairs. Subjects were mailed the Academic Career Development Survey, consisting of 144 items. Results indicated that self-reported physical and mental health, and professional and personal life satisfaction were high for both males and females. Both males and females placed high importance on their career and on marriage/other intimate relationships; however, both reported high levels of dissatisfaction with these factors. Gender differences were found in both satisfaction and type of stress reported; no gender differences were found in composite teaching and research performance indices. Salary data, obtained for 42 matched pairs, indicated similar salary levels for men and women. Results were discussed with respect to prior research on gender differences and the academic career.  相似文献   
68.
69.
Despite a substantial body of research suggesting genetic influence on educationally relevant behavioural traits, it is not clear how the nature–nurture question is perceived by teachers. In order to answer this question, we surveyed 667 UK primary school teachers, and for comparison also surveyed 1,340 parents about their perceptions of genetic and environmental influence on personality, intelligence, behaviour problems, learning difficulties, and mental illness. For these five domains of behaviour, the percentages of teachers who reported that genetics were at least as important as environment were .87, .94, .43, .94, and .91, respectively. Results for parents were similar (.92, .93, .54, .86, and .89). We also found that 80% of teachers reported no coverage of genetics during teacher training.  相似文献   
70.
Robert W. Bell 《PRIMUS》2017,27(3):406-417
Abstract

Mentoring undergraduate students in research is both rewarding and challenging. In this paper we present how we established a summer Research Experience for Undergraduates (REU) program in the mathematical sciences at Michigan State University. A goal of our REU is to include students who are at an early stage of their study of mathematics. We share our experiences in recruiting students, designing research projects, and mentoring our participants. We discuss the challenges we faced and the solutions we found while working with a diverse group of undergraduate students from across the nation.  相似文献   
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