The influence of the frontal surface area and swim velocity variation in front crawl active drag

Purpose The aims of this study were to 1) compare active drag (D-a) calculation between a single land-based measurement of frontal surface area (FSA) and in-water FSA measures obtained at key events of the arm pull (1, right upper-limb catch; 2, right upper-limb insweep; 3, right upper-limb exit and left upper-limb catch; 4, left upper-limb insweep; and 5, left upper-limb exit and right upper-limb catch) at front crawl swimming, and 2) compare mechanical power variables computed based on these two approaches. Methods Seventeen swimmers (11, male; 6, female; 16.15 +/- 0.94 yr old) were recruited. The FSA was measured based on two approaches: (i) nonvariation, that is, assuming a constant value, and (ii) variation, that is, calculated in each key event of the front crawl swim. Active drag based on a nonvariation of the FSA was measured using the Velocity Perturbation method. Active drag based on a variation approach was measured in each key event of the front crawl according to the law of linear motion. Pairedt-test (P <= 0.05), simple linear regression models, and Bland-Altman plots between assessment methods (variation vs nonvariation) were computed. Results The FSA (variation) was higher than when assuming a nonvariation (0.1110 +/- 0.010 vs 0.0968 +/- 0.010 m(2), Delta = 15.69%,t= 4.40,P< 0.001,d= 0.95). Active drag (variation) was also significantly higher than when assuming a nonvariation (88.44 +/- 25.92 vs 75.41 +/- 15.11 N, Delta = 16.09%,t= 3.66,P= 0.002,d= 0.61). Conclusions Besides the FSA, swim velocity also changes during the front crawl arm pull. The variation of both variables had a significant effect on the active drag measurement and consequently on mechanical power and total power input variables.This work is supported by national funds (FCT-Portuguese Foundation for Science and Technology) under the project UIDB/04045/2020. There were no conflicts of interests. The results of this study do not constitute endorsement by the American College of Sports Medicine. The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation.info:eu-repo/semantics/publishedVersio

Phonon anomalies due to strong electronic correlations in layered organic metals

We show how the coupling between the phonons and electrons in a strongly correlated metal can result in phonon frequencies which have a non-monotonic temperature dependence. Dynamical mean-field theory is used to study the Hubbard-Holstein model that describes the \kappa-(BEDT-TTF)_2 X family of superconducting molecular crystals. The crossover with increasing temperature from a Fermi liquid to a bad metal produces phonon anomalies that are consistent with recent Raman scattering and acoustic experiments.Comment: 6 pages, 3 eps figure

Threshold criterion for wetting at the triple point

Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete wetting, or (in the intermediate case) exhibit a wetting transition. An unusual variety of wetting transitions at the triple point is found in the case of a specific adsorption potential of intermediate strength. The general threshold for wetting near the triple point is found to be close to that predicted with a heuristic model of Cheng et al. This same conclusion was drawn in a recent experimental and simulation study of Ar on CO_2 by Mistura et al. These results imply that a dimensionless wetting parameter w is useful for predicting whether wetting behavior is present at and above the triple temperature. The nonwetting/wetting crossover value found here is w circa 3.3.Comment: 15 pages, 8 figure

Nursing teamwork in the care of older people: A mixed methods study

Healthcare is increasingly complex and requires the ability to adapt to changing demands. Teamwork is essential to delivering high quality care and is central to nursing. The aims of this study were to identify the processes that underpin nursing teamwork and how these affect the care of older people, identify the relationship between perceived teamwork and perceived quality of care, and explore in depth the experience of working in nursing teams. The study was carried out in three older people's wards in a London teaching hospital. Nurses and healthcare assistants completed questionnaires (n=65) on known dynamics of teamwork (using the Nursing Teamwork Survey) together with ratings of organisational quality (using an adapted AHRQ HSPS scale). A sample (n=22; 34%) was then interviewed about their perceptions of care, teamwork and how good outcomes are delivered in everyday work. Results showed that many care difficulties were routinely encountered, and confirmed the importance of teamwork (e.g. shared mental models of tasks and team roles and responsibilities, supported by leadership) in adapting to challenges. Perceived quality of teamwork was positively related to perceived quality of care. Work system variability and the external environment influenced teamwork, and confirmed the importance of team adaptive capacity. The CARE model shows the centrality of teamwork in adapting to variable demand and capacity to deliver care processes, and the influence of broader system factors on teamworking

1970 performance of corn hybrids in Illinois : with 1968-1969 averages

Cover title.Chiefly tables

Standardization of research methods employed in assessing the interaction metallic-based nanoparticles and the blood-brain barrier: present and future perspectives

peer-reviewedThe full text of this article will not be available until the embargo expires on the 18/01/2020.Treating diseases of the central nervous system (CNS) is complicated by the presence of the blood-brain barrier (BBB), a semipermeable boundary layer protecting the CNS from toxins and homeostatic disruptions. However, this layer also excludes almost 100% of therapeutics, impeding the treatment of CNS diseases. The advent of nanoparticles, in particular metallic-based nanoparticles, presents the potential to overcome this barrier and transport drugs into the CNS. Recent interest in metallic-based nanoparticles has generated an immense array of information pertaining to nanoparticles of different materials, sizes, morphologies, and surface properties. Nanoparticles with different physico-chemical properties lead to distinct nanoparticle-host interactions; yet, comprehensive characterization is often not completed. Similarly, in vivo testing has involved a mixed evaluation of parameters, including: BBB permeability, integrity, biodistribution, and toxicity. The methods applied to assess these parameters are inconsistent; this complicates the comparison of different nanoparticle-host system responses. A systematic review was conducted to investigate the methods by which metallic-based nanoparticles are characterized and assessed in vivo. The introduction of a standardized approach to nanoparticle characterization and in vivo testing is crucial if research is to transition to a clinical setting. The approach suggested, herein, is based on equipment and techniques that are accessible and informative to facilitate the routine incorporation of this standardized, informative approach into different research settings. Thorough characterization could lead to improved interpretation of in vivo responses, which could clarify nanoparticle properties that result in favorable in vivo outcomes whilst exposing nanoparticle-specific weaknesses. Only then will researchers successfully identify nanoparticles capable of delivering life-saving therapeutics across the blood-brain barrier

1967-1969 performance of corn hybrids in Illinois

Cover title

Measuring geometric phases of scattering states in nanoscale electronic devices

We show how a new quantum property, a geometric phase, associated with scattering states can be exhibited in nanoscale electronic devices. We propose an experiment to use interference to directly measure the effect of the new geometric phase. The setup involves a double path interferometer, adapted from that used to measure the phase evolution of electrons as they traverse a quantum dot (QD). Gate voltages on the QD could be varied cyclically and adiabatically, in a manner similar to that used to observe quantum adiabatic charge pumping. The interference due to the geometric phase results in oscillations in the current collected in the drain when a small bias across the device is applied. We illustrate the effect with examples of geometric phases resulting from both Abelian and non-Abelian gauge potentials.Comment: Six pages two figure

Spin induced multipole moments for the gravitational wave flux from binary inspirals to third Post-Newtonian order

Using effective field theory techniques we calculate the source multipole moments needed to obtain the spin contributions to the power radiated in gravitational waves from inspiralling compact binaries to third Post-Newtonian order (3PN). The multipoles depend linearly and quadratically on the spins and include both spin(1)spin(2) and spin(1)spin(1) components. The results in this paper provide the last missing ingredient required to determine the phase evolution to 3PN including all spin effects which we will report in a separate paper.Comment: 35 pages, 7 figures. Published versio