Intra- and inter-session reliability of vertical jump performance in healthy middle-aged and older men and women

Abstract

Despite its widespread use in performance assessment, the reliability of vertical jump in an ageing population has not been addressed properly. The aim of the present study was to assess intra- and inter-day reliability of countermovement jump in healthy middle-aged (55–65 years) and older (66–75 years) men and women. Eighty-two participants were recruited and asked to perform countermovement jumps on two different occasions interspersed by 4 weeks. The middle-aged groups exhibited excellent absolute reliability for flight height, jump height, peak force, peak power, peak force/body mass, and peak power/body mass, with coefficients of variation ranging from 2.9% to 7.2% in men and from 3.6% to 6.9% in women and moderate-to-high intraclass correlations (0.75 to 0.97 in men; 0.77 to 0.95 in women). The older groups displayed good coefficients of variation (4.2% to 10.8% in men and 3.4% to 9.5% in women), but the intraclass correlations were low-to-high (0.43 to 0.84 in men; 0.42 to 0.93 in women). Overall, intra-session reliability was higher than inter-session reliability. Peak power was by far the most consistent variable, whereas flight and jump height had the most marked variability. The minimum detectable change varied from 10.5% to 33%, depending on the variable examined, suggesting important implications for intervention studies.     

Stretching of DNA confined in nanochannels with charged walls

There is currently a growing interest in control of stretching of DNA inside nanoconfined regions due to the possibility to analyze and manipulate single biomolecules for applications such as DNA mapping and barcoding, which are based on stretching the DNA in a linear fashion. In the present work, we couple Finite Element Methods and Monte Carlo simulations in order to study the conformation of DNA molecules confined in nanofluidic channels with neutral and charged walls. We find that the electrostatic forces become more and more important when lowering the ionic strength of the solution. The influence of the nanochannel cross section geometry is also studied by evaluating the DNA elongation in square, rectangular, and triangular channels. We demonstrate that coupling electrostatically interacting walls with a triangular geometry is an efficient way to stretch DNA molecules at the scale of hundreds of nanometers. The paper reports experimental observations of λ-DNA molecules in poly(dimethylsiloxane) nanochannels filled with solutions of different ionic strength. The results are in good agreement with the theoretical predictions, confirming the crucial role of the electrostatic repulsion of the constraining walls on the molecule stretching.     

Comparison of Freelite and N-Latex serum free light chain assays: a critical review

IntroductionThe measurement of serum free light chain (FLC) represents a fundamental aspect on the assessment of patients with monoclonal gammopathies (MG). Different analytical methods for FLC have become available with the possibility to obtain different value with a substantial impact on the assessment of patients with MG. This study aimed to evaluate FLC results obtained with two different assays and how the difference value obtained can impact in the patient’s assessment.Materials and methodsNinety-three patient serum samples that underwent analysis for FLC with two different methods, Serum Freelite (The Binding Site, Birmingham, UK) and N-Latex FLC (Siemens, Marburg, Germany), were included in this retrospective study. Statistical analysis was performed to evaluate correlation, difference, and the grade of concordance between the results obtained with the two methods.ResultsSignificant statistical differences between the results obtained from the two methods were found (P < 0.05). A good correlation was found (0.99 for κ FLC, 0.95 for λ FLC, and 0.94 for the κ/λ ratio, respectively). We found a weighted kappa value of 0.65 for κ/λ ratio, 0.65 for λ FLC and 0.90 for κ FLC. A positive bias found with the Bland-Altman plot mirrors overestimation of κ FLC and κ/λ ratio with Freelite compared to N-Latex, whilst a negative bias underscores underestimation of λ FLC by Freelite compared to N-Latex.ConclusionAlthough in general the concordance between Freelite and N-Latex appears satisfactory, several discrepancies could be evidenced and consequently the two assays are not interchangeable.     

Explorations of a Paradox in Curriculum Control: Resistance to Open-ended Science Inquiry in a School for Self-directed Learning

Despite official government srt (in various jurisdictions around the world) for providing students with opportunities to construct their own knowledge within the context of formal schooling, school science systems continue to place greatest priority on teaching and learning of products of science (e.g., laws and theories), while compromising students’ opportunities to develop realistic conceptions about science and expertise for doing science. Based on qualitative data analyzed using constant comparative methods (based on constructivist grounded theory), we found this also to be the case – paradoxically – in a school belonging to the Canadian Coalition for Self-directed Learning (CCSDL). Schools in this coalition espouse, among various goals, enabling students to construct their own knowledge, in ways and directions suiting their individual needs, interests, perspectives, and abilities, in addition to gaining access to knowledge developed by society. The science department within the coalition school in this study experienced considerable difficulty realizing this goal, despite school-level administrative support for a concerted effort to reinvent itself along these lines. Factors that appeared to influence the science department’s efforts included those in each of Schwab’s (1969) educational "commonplaces;” that is, the curriculum, teachers, students, and the milieu surrounding teaching and learning. Further analysis suggests that results can be explained through reference to a Kuhnian (1962/1996) paradigm conflict – in which the school’s administrative and curricular committee and other members of the CCSDL were unsuccessful in convincing members of the science department (who, in turn, appeared to be supported by the provincial government, parents, and students) to make provisions for more student-directed, openended science inquiry. Assuming that student-led scientific inquiry continues to be an important curricular goal, efforts must continue to be made, therefore, to convince members of the mainstream paradigm that it is a worthy goal.     

Metabolic optimisation of the basketball free throw

The free throw (FT) is a fundamental basketball skill used frequently during a match. Most of actual play occurs at about 85% of maximum heart rate (HR). Metabolic intensity, through fatigue, may influence a technically skilled move as the FT is. Twenty-eight under 17 basketball players were studied while shooting FTs on a regular indoor basketball court. We investigated FT accuracy in young male basketball players shooting at three different HRs: at rest, at 50% and at 80% of maximum experimentally obtained HR value. We found no significant FT percentage difference between rest and 50% of the maximum HR (FT percentage about 80%; P > 0.05). Differently, at 80% of the maximum HR the FT percentage decreased significantly by more than 20% (P < 0.001) down to about 60%. No preliminary warm-up is needed before entering game for the FT accuracy. Furthermore, we speculate that time-consuming, cooling-off routines usually performed by shooters before each FT may be functional to improve its accuracy.