Culturally relevant inquiry-based laboratory module implementations in upper-division genetics and cell biology teaching laboratories

Today, more minority students are entering undergraduate programs than ever before, but they earn only 6% of all science or engineering PhDs awarded in the United States. Many studies suggest that hands-on research activities enhance students' interest in pursuing a research career. In this paper, we present a model for the implementation of laboratory research in the undergraduate teaching laboratory using a culturally relevant approach to engage students. Laboratory modules were implemented in upper-division genetics and cell biology courses using cassava as the central theme. Students were asked to bring cassava samples from their respective towns, which allowed them to compare their field-collected samples against known lineages from agricultural stations at the end of the implementation. Assessment of content and learning perceptions revealed that our novel approach allowed students to learn while engaged in characterizing Puerto Rican cassava. In two semesters, based on the percentage of students who answered correctly in the premodule assessment for content knowledge, there was an overall improvement of 66% and 55% at the end in the genetics course and 24% and 15% in the cell biology course. Our proposed pedagogical model enhances students' professional competitiveness by providing students with valuable research skills as they work on a problem to which they can relate.     

The effects of acute stretching on hamstring muscle fatigue and perceived exertion

The aim of this study was to examine the effects of an acute stretching regime on hamstring muscle fatigue and rating of perceived exertion during a dynamic, sub-maximal bout of resistance exercise. Sixteen healthy males (age 25.7 +/- 4.3 years, height 1.81 +/- 0.06 m, body mass 87.5 +/- 15.1 kg; mean +/- s) and 16 healthy females (age 24.9 +/- 4.5 years, height 1.67 +/- 0.06 m, body mass 62.9 +/- 9.4 kg) volunteered to participate in two experimental sessions. After establishing their one-repetition maximum for the hamstring curl, the participants were assigned at random to one of two groups. Group 1 performed three bouts of 20 s hamstring stretches with the assistance of one of the investigators, while group 2 did not perform the stretches; instead, they sat resting for 3 min. Then, after stretching or resting, the participants performed as many hamstring curls as they could at 60% of their one-repetition maximum established earlier. All participants were assessed for their perceived exertion using a modified Borg category ratio (CR-10) scale. The participants returned within 1 week to complete the experiment. This time group 1 did not perform hamstring stretches, whereas group 2 did. As on the first occasion, all participants performed hamstring curls after stretching or resting. The participants in group 1 were able to perform more curls on the second day of testing than their counterparts in group 2. There were no significant differences between males and females or between the stretch and non-stretch conditions. There was a significantly higher first repetition rating of perceived exertion for the stretch condition (2.88 +/- 1.01) than for the non-stretch condition (2.50 +/- 0.95); there was no significant difference in the median ratings of perceived exertion between the stretch and non-stretch conditions. Significantly higher power function exponents were exhibited in the non-stretch (0.57 +/- 0.16) than in the stretch condition (0.51 +/- 0.12). In addition, females exhibited significantly higher power function exponents than males, irrespective of stretch condition and day (females: 0.59 +/- 0.12; males: 0.49 +/- 0.11). In conclusion, we found a small but statistically significant effect of an acute bout of stretching on ratings of perceived exertion during fatiguing hamstring muscle resistance exercise.     

Substance abuse and behavioral correlates of sexual assault among South African adolescents

OBJECTIVE: The aim of this article is twofold: first, to examine the prevalence of being the victim of actual and attempted rape among a large representative sample of Cape Town high school students; and second, to identify the correlates of sexual assault for both boys and girls, including alcohol, tobacco and other drug use, behavioral problems, and suicidality. METHOD: Data for this study were derived from the 1997 South African Community Epidemiology Network on Drug Use (SACENDU) school survey. A stratified sampling procedure was used to select students in Grades 8 and 11 at non-private high schools in Cape Town. A total of 2,946 students completed a survey consisting of socio-demographic questions and items about substance abuse, sexual activity, and other adolescent health risk behaviors. A subsample of 939 was randomly selected to complete items about sexual violence. RESULTS: The results revealed that 8.4% of respondents were victims of attempted rape, while 5.8% were victims of actual rape. Ordinal logistic regression showed that girls were 3.9 times more likely than boys to have been victims of sexual abuse. Family structure was also significantly related to rape as persons who lived with a single parent (OR = 1.74, CI = 1.00-3.04) and those who resided with one biological parent and one step parent (OR = 2.59, CI = 1.34-5.01) were more likely to have been have been victims of sexual abuse than those living with both biological parents. Alcohol use (OR = 2.0, CI = 1.10-3.62), anti-social behavior (stolen property, caused physical damage to property, bullied others, or been in physical fights) (OR = 1.44, CI = 1.12-1.86), suicidal dialogue (OR = 2.48, CI = 1.19-5.19), and suicidal attempts (OR = 3.2, CI = 1.65-6.30) were also significant predictors of sexual abuse victimization. Racially classified social groups (RCSG), age, drug use, and cigarette smoking were not significant predictors of sexual abuse victimization, while socioeconomic status was found to be marginally significant. CONCLUSION: This study reinforces the importance of multiple factors including alcohol use, anti-social behavior, suicidal thoughts and actions, and family structure with respect to sexual assault of adolescents in South Africa. Establishing and strengthening intervention programs, school based child protective protocols, professional education of teachers and school personnel, community prevention programs, and initiatives could help prevent adolescent sexual violence and reduce the sequelae associated with this problem.     

我们是否迈向高等教育的自由放任主义?

多年以来,许多发展中国家对高等教育的发展漠不关心,忽视高等教育发展、缩减高等教育的公共投资,纵容自由放任主义,甚至采取了高等教育市场化的政策;结果在高等教育领域中市场变得十分活跃。然而大多数发展中国家的市场经济是“不完全”或“不完善”的,因此高等教育市场化改革的结果很不理想。事实上,市场力量在一些国家造成了灾难性的后果。这种“市场化”国家政策来自以下两个错误的假设:高等教育对社会的发展并不重要,国家可以为了市场而忽略其提供高等教育的责任。但是事实表明,我们已经为这些错误认识付出了昂贵的代价。国家在高等教育发展中的角色是至关重要、不可或缺的。     

Batteries for wearables

<正>Batteries that convert the stored chemical energy directly into electricity have been known for hundreds of years.Take the lithium-ion battery as representative because of its high energy-conversion efficiency and long cycle life.It is widely used as a power accessory for electronic devices and has become an important part of modern electronics.     

Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults: A prospective cohort study

Purpose:This study aimed to examine the associations of accelerometer-derived steps volume and intensity with hospitalizations and all-cause mortality in older adults.Methods:This prospective cohort study involved 768 community-dwelling Spanish older adults(78.8±4.9 years,mean±SD;53.9% females)from the Toledo Study for Healthy Aging(2012-2017).The number of steps per day and step cadence(steps/min) were derived from a hip-mounted accelerometer worn for at least 4 days at baseline.Participants we...     

中国体育运动的现状、潜力及发展战略

1994年以来,中国政府日益认识到体育运动对人民身心健康的重要性,越来越注重发展体育运动,坚持发展和促进大众体育,推行全民健身计划,增强人民体质。     

Postcranial disparity of galeaspids and the evolution of swimming speeds in stem-gnathostomesOA

Galeaspids are extinct jawless relatives of living jawed vertebrates whose contribution to understanding the evolutionary assembly of the gnathostome bodyplan has been limited by absence of postcranial remains.Here,we describe Foxaspis novemura gen.et sp.nov.,based on complete articulated remains from a newly discovered Konservat-Lagerstatte in the Early Devonian(Pragian,～410 Ma) of Guangxi,South China.F,novemura had a broad,circular dorso-ventrally compressed headshield,slender trunk and strong...