Ecological Study of Graduation Rates and GPA in a Library Credit Course     

Christina Heady  Megan M. Morrison  Joshua Vossler 《The Journal of Academic Librarianship》2018,44(5):642-649

The purpose of this ecological study was to examine the impact of a library credit course on graduation rates and GPA using pre-existing records. Over 20?years of aggregate institutional data were analyzed to evaluate the course's impact on first-time-full-time, white, and black students. Results were mixed: students who took the course were less likely to graduate than their peers who did not take the course but enjoyed slightly higher GPAs at graduation. It was discovered that students taking the course are not representative of the overall student body and struggle academically. Implications for revisions to the library credit course are discussed.  相似文献   

A new approach to explore the knowledge transition path in the evolution of science & technology: From the biology of restriction enzymes to their application in biotechnology     

Xiaojun Hu  Ronald Rousseau 《Journal of Informetrics》2018,12(3):842-857

In this contribution, we develop a new approach to explore the process of knowledge transition from discovery-oriented science to technological fields, via applications-oriented research, including a mediator set. This trajectory is referred to as the D-A-T trajectory. It is shown how it can be constructed and measures are proposed to characterize the relational strength among different environments (discovery oriented research, applications-oriented research and patents) and the speed of evolution. Our approach is illustrated by a case study of three fundamental restriction enzymes articles. Among other results we found that 387 patents cited 124 of the 988 articles (a share of 12.55%) in the mediator set. Defining the non-patent references (NPR) transition rate as the number of citing patents divided by the number of articles in the mediator set yields a value 0.392. Our results suggest that the D-A-T path acts as a backbone and reveals important “invisible contributions” of an original scientific work during its evolution from discovery oriented research to outside academia. Our contribution provides a useful tool for bridging the existing gap in detecting the transition of knowledge between science and technology.  相似文献   

废蚕丝中提取丝胶工艺研究     

蓝建京  甘配芳 《河池学院学报》2011,31(5):56-60

通过对透析法、酸析法和冰冻法提取丝胶效果的比较,得出冰冻法是提取丝胶的较好的方法,其最佳的提取条件是:pH=4,-20℃,冰冻时间为13 h,丝胶液浓度为32.8%。  相似文献   

Maximal heart rate declines linearly with age independent of cardiorespiratory fitness levels     

Cemal Ozemek  Mitchell H. Whaley  W. Holmes Finch  Leonard A. Kaminsky 《European Journal of Sport Science》2017,17(5):563-570

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HR_max) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HR_max with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HR_max for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R² (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HR_max explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HR_max.  相似文献   

4周下肢间歇负压干预对优秀赛艇运动员心率变异性和儿茶酚胺的影响     

董徽徽  高炳宏 《上海体育学院学报》2020,(4):78-83

目的探讨下肢间歇负压干预对赛艇运动员心率变异性(HRV)相关指标和儿茶酚胺的影响。方法将国家赛艇队的14名运动员分为试验组和对照组,试验组运动员每周用间歇负压干预5 d,持续4周,对照组无其他干预方式。试验期间均对2组运动员进行HRV相关指标和儿茶酚胺的测试。结果试验前2组运动员各指标均无统计学差异。开始干预后2组的变化如下:①在时域指标中,试验组正常窦性R-R间期标准差(SDNN)在第3周时高于对照组(P<0.05)。②在频域指标中,试验组高频(HF)值在第2周和第3周时高于对照组(P<0.05),而其高频与低频比(LF/HF)在第1、3和4周时低于对照组(P<0.05)。③2组儿茶酚胺组内、组间比较均无统计学差异,但试验组儿茶酚胺下降程度比对照组高。结论4周的间歇负压干预对运动员自主神经系统功能的恢复有明显促进作用,对儿茶酚胺的分泌也具有抑制趋势;这有利于降低运动员心脏负荷,促进运动后的生理恢复。  相似文献   

优秀女子足球运动员间歇性恢复能力的评价研究     

秦旸  张娜 《南京体育学院学报(社会科学版)》2016,(2):103-107

目的：：探讨运用限定级数YO-YO IR2测试以及心率恢复速率评价我国优秀女足运动员的间歇恢复能力。方法：运用测试法对2013年冬训期间的10名国家女足运动员进行YO-YO IR2测试、心率监控以及比赛监测，采集运动员测试跑动距离、心率特征以及比赛中高强度跑动距离，进行统计学分析。结论：女足运动员YO-YO IR2测试结果以及心率恢复速率与比赛中的高强度跑动能力具有紧密相关性，提示YO-YO IR2测试以及心率监控可以作为评价女足运动员间歇性恢复能力的有效方法。与传统的力竭性YO-YO IR2测试法相比，采用限定级数的YO-YO IR2测试后的心率恢复速率评价更易于女足运动员接受，在训练中具有更好的适用性。  相似文献   

Thermoneutral immersion exercise accelerates heart rate recovery: A potential novel training modality     

Mauricio Garzon  Olivier Dupuy  Laurent Bosquet  Anil Nigam  Alain Steve Comtois  Martin Juneau 《European Journal of Sport Science》2017,17(3):310-316

This study compared heart rate recovery (HRR) after incremental maximal exercise performed at the same external power output (P_ext) on dry land ergocycle (DE) vs. immersible ergocycle (IE). Fifteen young healthy participants (30?±?7 years, 13 men and 2 women) performed incremental maximal exercise tests on DE and on IE. The initial P_ext on DE was 25?W and was increased by 25?W/min at a pedalling cadence between 60 and 80?rpm, while during IE immersion at chest level in thermoneutral water (30°C), the initial P_ext deployment was at a cadence of 40?rpm which was increased by 10?rpm until 70?rpm and thereafter by 5?rpm until exhaustion. Gas exchange and heart rate (HR) were measured continuously during exercise and recovery for 5?min. Maximal HR (DE: 176?±?15 vs. IE 169?±?12?bpm) reached by the subjects in the two conditions did not differ (P?>?.05). Parasympathetic reactivation parameters (ΔHR from 10 to 300?s) were compared during the DE and IE HR recovery recordings. During the IE recovery, parasympathetic reactivation in the early phase was more predominant (HRR at Δ10–Δ60?s, P?<?.05), but similar in the late phase (HRR at Δ120–Δ300?s, P?>?.05) when compared to the DE condition. In conclusion, incremental maximal IE exercise at chest level immersion in thermoneutral water accelerates the early phase parasympathetic reactivation compared to DE in healthy young participants.  相似文献   

国外智慧城市视阈下的数字档案研究热点概览     

刘坤锋  庞宇飞  郑雪丽  刘永 《档案管理》2020,(3):101-103

本文对国外智慧城市视阈下的数字档案研究热点文献进行梳理,介绍了数字档案检索优化服务、数字档案交互性和可视化服务、数据开放与用户参与以及智慧城市专项数字档案处理等方面的理论和应用研究成果。这些研究在面向需求、技术应用和专项融合等方面较为深入且操作性较强,具有借鉴意义。  相似文献   

美术教育让民族文化由"遗产"转向"资源"     

王晓珍 《美育学刊》2020,11(2):14-19

在全球化的今天,要实现中华民族文化的繁荣,首先应客观了解我国民族文化形成过程中出现的多样性文化特点,实现文化自觉,坚定文化自信,才能真正激活民族性格中的文化基因。美术学科涉及中华民族物质文化与非物质文化的形态,从多样性文化的角度出发,通过引入图像学、艺术人类学等相关学科的专业知识与观察方法,将丰富的民族文化遗产实现当代文化资源的转变,在传承优秀民族文化的基础上拓展学生解决实际问题的创新能力,为美术学科实现社会价值提供更多样的思考。  相似文献   

Effects of heat acclimation on hand cooling efficacy following exercise in the heat     

Elizabeth L. Adams  Lesley W. Vandermark  J. Luke Pryor  Riana R. Pryor  Rachel M. VanScoy  Craig R. Denegar 《Journal of sports sciences》2017,35(9):828-834

This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO₂ max], 54.1 ± 1.3 ml·kg^?1·min^?1) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO₂ max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90–240 min of treadmill or stationary bike exercise (60–80% VO₂ max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min^?1) had a greater cooling rate than NC (0.013 ± 0.003°C·min^?1) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min^?1) was similar to NC (0.025 ± 0.002°C·min^?1) (0.004°C [?0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min^?1) was similar to when NHA (0.020 ± 0.003°C·min^?1) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.  相似文献