Braking ground reaction force during 90deg sidestep cut and its relationship to leg muscle strength

Previous studies on change of direction (COD) have reported that braking is an important factor for COD performance. However, previous studies have focused on the plant step and the penultimate step (PEN), thus little is known about deceleration before these steps. This study compared ground reaction forces (GRF) of two braking steps, the PEN and the step prior to PEN (PEN-1), the entry and exit velocity of the COD, and muscle function measures (leg press and leg curl one-repetition maximum, isometric and isokinetic strength, and drop jump performance) between faster and slower participants for a 90o sidestep cut. This study also examined the associations between the time taken from 1 m before and 1 m after COD (1-1 m COD time), braking GRF during deceleration and muscle function. Twenty-two male recreational athletes from AFL (n = 2), soccer (n = 8), rugby (n = 2), basketball (n = 5), squash (n = 1) and tennis (n = 4), performed a total of six cuts with their dominant (DL) and non-dominant legs (NDL). The faster group (n =10; DL: 0.19 ± 0.02 s, NDL: 0.22 ± 0.02 s) and the slower group (n = 10; DL: 0.24 ± 0.02 s, NDL: 0.31 ± 0.04 s) as well as pooled (n = 20) DL and NDL (DL: 0.21 ± 0.03 s, NDL: 0.26 ± 0.04 s) were used for analyses. Dependent variables between the groups were compared using independent t-tests with sequential Bonferroni corrections to control for type I error. Pearson’s correlation was used to examine the relationship between the 1-1 m COD time and dependent variables. Faster DL COD participants showed significantly greater change in braking impulse from PEN-1 to PEN (-0.50 ± 0.31 vs -0.20 ± 0.15 m⋅s-1, p = 0.027) whereas faster NDL COD participants showed greater isometric knee flexor torque (1.94 ± 0.25 vs 1.63 ± 0.26 Nm⋅kg-1, p = 0.005), isometric extensor torque (3.37 ± 0.42 vs 3.17 ± 0.71 Nm⋅kg-1, p = 0.017) and concentric isokinetic (90o⋅s-1) knee extensor torque (3.02 ± 0.47 vs 2.47 ± 0.39 Nm⋅kg-1, p = 0.03). Pooled DL and NDL comparison revealed significantly higher plant step braking impulse (0.61 ± 0.23 vs 0.47 ± 0.23 m⋅s-1, p = 0.043) and lower propulsive impulse (2.42 ± 0.47 vs 2.77 ± 0.47 m⋅s-1, p = 0.008) during DL COD. Faster NDL COD was associated with greater NDL eccentric knee flexor at 90o⋅s-1 (r = 0.648, p = 0.003), 60 cm drop jump (r = 0.556, p = 0.010), greater NDL isometric knee flexor torque (r = 0.473, p = 0.024) and greater NDL eccentric knee extensor at 90os-1 (r = 0.470, p = 0.041). These results indicate that mechanical factors influencing DL and NDL COD performance were different. In addition, deceleration steps ranged between three to five steps with braking between PEN-1 and PEN resulting in faster DL COD performance. Further studies are is required to examine the deceleration starting at PEN-1 and should consider multifactorial analyses to capture multiple strategies potentially implemented

A Study of Student Learning through Lectures Based on Information Processing Theory

This study provides an account of a naturalistic research into students' learning through lectures. It documents aspects of students' rating of courses and lecturers, the researcher's participant observation and students' note-taking behaviours during normal lectures in a naturally occurring classroom. Students' opinion about the course and the lecturers involved was collected by using a specially designed questionnaire. Access to students' learning was obtained by using audio-tapes of lectures and students' lecture notes. Analysis of lecture notes and interview data provided insights into the nature of, and factors influencing students' note-taking. It also called into question the value of some conventional wisdom about lecturing. This project described three phases of an extended research study planned to investigate how the effects of lecturers' styles interacted with students' cognitive processing of the corresponding lecture information and thus their note-taking behaviours. The first phase of this study involved an exploratory examination of both lecturing and note-taking at the same time under natural conditions for the purpose of revealing some promising factors for further investigation. It was uncovered that note-taking from lectures under certain conditions was in fact dependent on the lecturing styles. In the second phase of this study, a more complete framework, based on Information Processing Theory, was advanced to investigate both lecturing behaviours and the note-taking behaviours and performance of particular type of learners with different working memory capacity, learning styles and motivational types under various lecturing conditions. The third phase of this study was mainly concerned with testing hypotheses to check the reliability of research findings from the previous phases of this present study and in addition, note-taking behaviours of students in general was also investigated. Based upon Information Processing Theory, this study tried to integrate the research into lecturing and the research into note-taking into a unified framework. Such an attempt has provided a key to a fuller understanding of how lecturing processes (the cognitively oriented stimulus variables) influence students' learning processes (the cognitively orienting response variables) during the lectures. Such study has both theoretical orientations and practical implications for improving lecture effectiveness and students' learning (and note-taking) through lectures. The findings from this research suggest that the approach adopted in this investigation holds promise for improving our understanding of how lecturing could be presented efficiently to maximise the transmission of information, and eventually for improving the lecturing effectiveness by making it more adaptive to the needs, interests and learning styles of students and for improving learning by developing in students the strategies for effective note-taking from lectures. One considerable justification and contribution of this present study is that the research into students' cognitive processes during lectures has pursued purely descriptive studies in naturally occurring classroom settings. Such study could ensure that hypotheses and questions posed are relevant and sensible to the subsequent correlational and experimental research. Constructs and variables used in this research have ecological validity and the research designs have taken account of naturally occurring phenomena and other aspects of university lectures

Post-Markov master equation for the dynamics of open quantum systems

A systematic first-order correction to the standard Markov master equation for open quantum systems interacting with a bosonic bath is presented. It extends the Markov Lindblad master equation to the more general case of non-Markovian evolution. The meaning and applications of our `post'-Markov master equation are illustrated with several examples, including a damped two-level atom, the spin-boson model and the quantum Brownian motion model. Limitations of the Markov approximation, the problem of positivity violation and initial slips are also discussed.Comment: 7 pages, 2 figures, RevTe

Low Molecular Weight mRNA Encodes a Protein That Controls Serotonin 5-HT_(1c) and Acetylcholine M_1 Receptor Sensitivity in Xenopus Oocytes

Serotonin 5-HT_(1c) and acetylcholine M_1 receptors activate phosphoinositidase, resulting in an increased formation of IP_3 and 1,2 diacylglycerol. In Xenopus oocytes injected with mRNA encoding either of these receptors, Ca^(2+) released from intracellular stores in response to IP3 then opens Ca^(2+)-gated Cl^-channels. In the present experiments, oocytes expressing a transcript from a cloned mouse serotonin 5-HT_(1c) receptor were exposed to identical 15-s pulses of agonist, administered 2 min apart; the second current response was two to three times that of the first. However, in those oocytes coinjected with the 5-HT_(1c) receptor transcript and a low molecular weight fraction (0.3-1.5 kb) of rat brain mRNA, the second current response was ~50% of the first. Thus, the low molecular weight RNA encodes a protein (or proteins) that causes desensitization. Experiments using fura-2 or a Ca^(2+)-free superfusate indicated that desensitization of the 5-HT_(1c) receptor response does not result from a sustained elevation of intracellular Ca^(2+) level or require the entry of extracellular Ca^(2+). Photolysis of caged IP_3 demonstrated that an increase in IP_3 and a subsequent rise in Ca^(2+) do not produce desensitization of either the IP_3 or 5-HT_(1c) peak current responses. Furthermore, in oocytes coinjected with the low molecular weight RNA and a transcript from the rat M_1 acetylcholine receptor, the M_1 current response was greatly attenuated. Our data suggest that the proteins involved in attenuation of the M_1 current response and desensitization of the 5-HT_(1c) current response may be the same

Interaction of Human Serum Albumin with short Polyelectrolytes: A study by Calorimetry and Computer Simulation

We present a comprehensive study of the interaction of human serum albumin (HSA) with poly(acrylic acid) (PAA; number average degree of polymerization: 25) in aqueous solution. The interaction of HSA with PAA is studied in dilute solution as the function of the concentration of added salt (20 - 100 mM) and temperature (25 - 37$^{\circ}$C). Isothermal titration calorimetry (ITC) is used to analyze the interaction and to determine the binding constant and related thermodynamic data. It is found that only one PAA chain is bound per HSA molecule. The free energy of binding $\Delta G_b$ increases with temperature significantly. $\Delta G_b$ decreases with increasing salt concentration and is dominated by entropic contributions due to the release of bound counterions. Coarse-grained Langevin computer simulations treating the counterions in an explicit manner are used study the process of binding in detail. These simulations demonstrate that the PAA chains are bound in the Sudlow II site of the HSA. Moreover, $\Delta G_b$ is calculated from the simulations and found to be in very good agreement with the measured data. The simulations demonstrate clearly that the driving force of binding is the release of counterions in full agreement with the ITC-data

Non-Markovian Quantum Trajectories of Many-Body Quantum Open Systems

A long-standing open problem in non-Markovian quantum state diffusion (QSD) approach to open quantum systems is to establish the non-Markovian QSD equations for multiple qubit systems. In this paper, we settle this important question by explicitly constructing a set of exact time-local QSD equations for $N$-qubit systems. Our exact time-local (convolutionless) QSD equations have paved the way towards simulating quantum dynamics of many-body open systems interacting with a common bosonic environment. The applicability of this multiple-qubit stochastic equation is exemplified by numerically solving several quantum open many-body systems concerning quantum coherence dynamics and dynamical control.Comment: 8 pages, 2 figures. manuscript revised and reference update

States and changes-of-state in the semantics of result roots

A major challenge for event structural theories that decompose verbs into event templates and roots relates to the syntactic distribution of roots and what types of event structures roots can be integrated into. ONTOLOGICAL APPROACHES propose roots fall into semantic classes, such as manner versus result, which determine root distribution (Rappaport Hovav and Levin 1998, 2010). FREE DISTRIBUTION APPROACHES, in contrast, hold that root distribution is not constrained by semantic content and roots are free to integrate into various types of event structures (Borer 2005; Acedo-Matellán and Mateu 2014). We focus on two different classes of verbs classified as result verbs in Rappaport Hovav and Levin’s (1998, 2010) sense and their ability to appear in resultative constructions. We build on Beavers and Koontz-Garboden’s (2012, 2020) proposal that the roots underlying these verbs fall into two classes: property concept roots, which denote relations between individuals and states, and change-of-state roots, which on our proposal, denote relations between individuals and events of change. We show that change-of-state roots, but not property concept roots, are able to appear in the modifier position of resultative constructions by providing naturally occurring examples of such resultatives. Combining the proposed lexical semantics of these two classes of roots with a reformulation of an ONTOLOGICAL APPROACH solely dependent on a root’s semantic type, we show that this analysis makes novel and accurate predictions about the possibility of the two classes of roots appearing in resultative constructions and the range of interpretations available when change-of-state roots are integrated into resultative event structure templates.This work received support from various sources: Yu was partially supported by the KU Leuven-funded C1-project Comparatives Under the Microscope (C14/20/041) awarded to Jeroen van Craenenbroeck, Guido Vanden Wyngaerd, and Dany Jaspers, Ausensi was supported by grant FFI2016-76045-P (AEI/MINEICO/FEDER, UE), an ICREA Academia awarded to Louise McNally, ROLLING 2017-SGR-165, Pla de Foment de la Recerca 2022PFR-URV-1, and the fellowship Juan de la Cierva-Formación FJC2021-046652-I (MCIN/AEI 10.13039/501100011033 and NextGenerationEU/PRTR), and Smith was partially supported by ERC-2017-COG769192 awarded to Andrew Koontz-Garboden

Probing terahertz surface plasmon waves in graphene structures

Epitaxial graphene mesas and ribbons are investigated using terahertz (THz) nearfield microscopy to probe surface plasmon excitation and THz transmission properties on the sub-wavelength scale. The THz near-field images show variation of graphene properties on a scale smaller than the wavelength, and excitation of THz surface waves occurring at graphene edges, similar to that observed at metallic edges. The Fresnel reflection at the substrate SiC/air interface is also found to be altered by the presence of graphene ribbon arrays, leading to either reduced or enhanced transmission of the THz wave depending on the wave polarization and the ribbon width.Comment: accepted for publication in Applied Physics Lette

Embedding the Zee-Wolfenstein neutrino mass matrix in an SO(10) x A4 GUT scenario

We consider renormalizable SO(10) Yukawa interactions and put the three fermionic 16-plets into the 3-dimensional irreducible A_4 representation. Scanning the possible A_4 representation assignments to the scalars, we find a unique case which allows to accommodate the down-quark and charged-lepton masses. Assuming type II seesaw dominance, we obtain a viable scenario with the Zee-Wolfenstein neutrino mass matrix, i.e., the Majorana mass matrix with a vanishing diagonal. Contributions from the charged-lepton mass matrix resolve the well-known problems with lepton mixing arising from the vanishing diagonal. In our scenario, fermion masses and mixings are well reproduced for both normal and inverted neutrino mass spectra, and b-tau Yukawa unification and definite predictions for the effective mass in neutrinoless double-beta decay are obtained.Comment: 19 pages, 3 figures, v2: final version for Phys. Rev.