Correlations between serum and salivary hormonal concentrations in response to resistance exercise

Abstract

The aim of present study was to examine the relationships between serum and salivary values of free testosterone, dehydroepiandrosterone, and cortisol before and after a session of resistance exercise. Twenty-eight healthy men (mean age 40 years, s = 4) participated in the present study. Serum and salivary samples were collected at rest and after a multiple-sets resistance exercise protocol, of approximately 25 minutes duration. Concentrations of free testosterone, dehydroepiandrosterone, and cortisol were measured using radioimmunoassay kits. No significant correlation was observed between serum free testosterone and salivary testosterone (r = 0.22 to 0.26, P > 0.05). Serum cortisol was significantly correlated with salivary cortisol before (r = 0.52, P = 0.005) and after (r = 0.62, P = 0.001) the exercise protocol. Serum and salivary concentrations of dehydroepiandrosterone were significantly correlated before (r = 0.68, P < 0.001) and after (r = 0.7, P < 0.001) exercise. The results of the present study suggest that even under exercise conditions, the salivary values of cortisol and dehydroepiandrosterone can reflect the behaviour of these hormones in blood. However, further studies are necessary to verify if salivary testosterone reflects the behaviour of serum free testosterone during resistance exercise.     

Fluid balance of elite Brazilian youth soccer players during consecutive days of training

Abstract

In this study we investigated pre-training hydration status, fluid intake, and sweat loss in 20 elite male Brazilian adolescent soccer players (mean ± s: age 17.2 ± 0.5 years; height 1.76 ± 0.05 m; body mass 69.9 ± 6.0 kg) on three consecutive days of typical training during the qualifying phase of the national soccer league. Urine specific gravity (USG) and body mass changes were evaluated before and after training sessions to estimate hydration status. Players began the days of training mildly hypohydrated (USG > 1.020) and fluid intake did not match fluid losses. It was warmer on Day 1 (33.1 ± 2.4°C and43.4 ± 3.2% relative humidity; P < 0.05) and total estimated sweat losses (2822 ± 530 mL) and fluid intake (1607 ± 460 mL) were significantly higher (P < 0.001) compared with Days 2 and 3. Data also indicate a significant correlation between the extent of sweat loss and the volume of fluid consumed (Day 1: r = 0.560, P = 0.010; Day 2: r = 0.445, P = 0.049; Day 3: r = 0.743, P = 0.0001). We conclude that young, native tropical soccer players arrive hypohydrated to training and that they exhibit voluntary dehydration; therefore, enhancing athletes' self-knowledge of sweat loss during training might help them to consume sufficient fluid to match the sweat losses.     

Interferential therapy effect on mechanical pain threshold and isometric torque after delayed onset muscle soreness induction in human hamstrings

Abstract

This study was undertaken to examine the acute effect of interferential current on mechanical pain threshold and isometric peak torque after delayed onset muscle soreness induction in human hamstrings. Forty-one physically active healthy male volunteers aged 18?33 years were randomly assigned to one of two experimental groups: interferential current group (n = 21) or placebo group (n = 20). Both groups performed a bout of 100 isokinetic eccentric maximal voluntary contractions (10 sets of 10 repetitions) at an angular velocity of 1.05 rad · s^?1 (60° · s^?1) to induce muscle soreness. On the next day, volunteers received either an interferential current or a placebo application. Treatment was applied for 30 minutes (4 kHz frequency; 125 μs pulse duration; 80?150 Hz bursts). Mechanical pain threshold and isometric peak torque were measured at four different time intervals: prior to induction of muscle soreness, immediately following muscle soreness induction, on the next day after muscle soreness induction, and immediately after the interferential current and placebo application. Both groups showed a reduction in isometric torque (P < 0.001) and pain threshold (P < 0.001) after the eccentric exercise. After treatment, only the interferential current group showed a significant increase in pain threshold (P = 0.002) with no changes in isometric torque. The results indicate that interferential current was effective in increasing hamstrings mechanical pain threshold after eccentric exercise, with no effect on isometric peak torque after treatment.     

Understanding the Gender Gap in Science and Engineering: Evidence from the Chilean College Admissions Tests

This study seeks to develop a better understanding of the underrepresentation of women in science and engineering by analyzing the gender gaps (a) in the interest in pursuing a science degree and (b) on science achievement. We use national-level college admissions data to examine gender differences and to explore the association between these outcomes and the attendance to single-sex or co-educational schools. The Chilean college admissions system provides a unique context to study these gender differences, since applicants who wish to pursue an undergraduate degree in science or engineering are required to take a high-stakes standardized science achievement test as part of the admission battery. This test has three subjects: biology, physics, and chemistry, and applicants must choose to be tested in only one of them. Significant gender differences exist for the examinees in their choice of subject and achievement on (the tests). Gender gaps favoring males are observed in the three forms. Both interest and achievement in science are associated with the sex composition of the school attended.     

Development,Evaluation and Use of a Student Experience Survey in Undergraduate Science Laboratories: The Advancing Science by Enhancing Learning in the Laboratory Student Laboratory Learning Experience Survey

Student experience surveys have become increasingly popular to probe various aspects of processes and outcomes in higher education, such as measuring student perceptions of the learning environment and identifying aspects that could be improved. This paper reports on a particular survey for evaluating individual experiments that has been developed over some 15 years as part of a large national Australian study pertaining to the area of undergraduate laboratories—Advancing Science by Enhancing Learning in the Laboratory. This paper reports on the development of the survey instrument and the evaluation of the survey using student responses to experiments from different institutions in Australia, New Zealand and the USA. A total of 3153 student responses have been analysed using factor analysis. Three factors, motivation, assessment and resources, have been identified as contributing to improved student attitudes to laboratory activities. A central focus of the survey is to provide feedback to practitioners to iteratively improve experiments. Implications for practitioners and researchers are also discussed.     

Within and beyond a grow-your-own-teacher program: Documenting the contextualized preparation and professional development experiences of critically conscious Latina teachers

ABSTRACT

This study provides an account of seven Latina teachers’ select educational, professional, and personal experiences over the past 10 years as they completed a grow-your-own-teacher program, became licensed teachers, and established themselves in Latinx minority–majority public schools within their rural, mid-western community. More specifically, as a Latina researcher and participant observer, I sought to better understand the culturally and linguistically diverse (CLD) Latina teachers’ process-oriented engagement and conscientization over time. Far from being ‘ready-made’ conscientized teachers, in this work I discuss the ways CLD Latina teachers’ multiple and developing identities as bilingual learners, mothers, racialized minorities in schools, and educated professionals serve as both burdens and gifts in their engagement and processes of conscientization for teaching CLD students. Through the use of critical literatures, and life and professional story methodologies informed by Chicana feminist epistemologies, I sought to privilege Latina teachers’ narratives as well as uncover the mechanisms and experiences that proved most impactful for their development and sustainment within white normative educational spaces. Findings illustrate an emergence of racialized, identitarian resources among Latinas and implicate a nuanced, culturally contextualized, pedagogical approach to pre-/in-service CLD teacher professional development that engages participants in reflective storying, critical inquiry, and restorative community building.     

A Qualitative Metasynthesis of Consultation Process Research: What We Know and Where to Go

ABSTRACT

Qualitative metasynthesis (QM) is a research methodology that permits the meaningful integration and interpretation of qualitative research. This study applies a QM approach combined with constructivist grounded theory methods, bolstered by several features of research credibility, to examine the state of consultee-centered consultation (CCC) and related relational, process-oriented school consultation research. A systematic search and retrieval process including two rounds of appraisal resulted in a final sample of 38 relevant studies from 1995 to 2014. Data analyses included two stages of coding/theme development. Integrated themes suggest a number of considerations regarding consultation implementation including: system-level factors; consultation structure; consultee voice, social-emotional support, and learning; ecological orientation and cultural responsiveness; and consultation training. Future research priorities stemming from these themes are identified and elaborated upon, as are future applications for QM in educational research.     

Using matrix norms to estimate the direction of arrival of planar waves on an ULA

SEAD method estimates the direction-of-arrival angles on an uniform linear array based on the difference between the two largest singular values, what is called differential spectrum. Although it presented an outstanding performance, the ability to indicate the source positions was not elucidated yet. Inspired by the differential spectrum formulation we derived a total differential spectrum and found out that the matrix norm induced by the vector 2-norm of a modified spatial covariance matrix can be used to estimate the direction-of-arrival of multiple plane waves. Indeed we show that matrix norms are estimators and we propose their use instead of the singular value decomposition in SEAD-based methods. We present a general mathematical expression in order to explicit the operating principles of the proposed methods. Consequently, we were able to explain how the relation between the arriving and the search angles produces the larger peaks on the differential spectrum. To evaluate the important role played by matrix norms, a thousand experiments were carried out. They showed that the proposed approach proved to be as accurate as the previous SEAD-based methods, while providing a significant reduction on runtime. It also outperformed well-established methods like MODEX regarding the estimation error.     

Exploring user acceptance of technology using social networks

The technology acceptance model (TAM) has been widely used to study user acceptance of new computer technologies. However, it does not incorporate social structure and influence as a significant factor. In this study, we ask the following questions: (i) What are the limitations of the existing TAM for studying virtual community? (ii) What is effect of social networks on user acceptance of technology for virtual community? and (iii) How can the influence of different types of social ties serve as a basis for exploring the user acceptance of technology in a virtual community? Here, we explore the possibility for extending TAM to incorporate the influence of the different types of social ties as a new theoretical construct. Preliminary analysis of data from a virtual community results show that weak and strong ties influence technology acceptance. The findings enable HCI researchers to account for influence of social ties in future investigations using TAM.     

The relative value of reading ability and IQ as predictors of teacher-reported behavior problems

Measures of early family adversity, pre-school-age IQ, school-age IQ, and reading ability were obtained from 779 Dunedin children. The data were used to examine the role of reading ability in the relationship between intellectual performance and teacher-reported behavior problems. Results of regression analyses showed that family adversity and pre-school-age IQ predicted problem behavior during the first year at school. However, reading scores accounted for a larger proportion of the variance in the later behavior problem scores than did school-age IQ scores, and when reading ability was entered in the regression equation before IQ, then reading but not IQ significantly predicted change in problem behavior during the primary school years. The results indicated that the association between IQ scores and problem behavior was mediated by reading ability and that a measure of school-age IQ has limited usefulness for models of primary school-age problem behavior.