Dynamics and kinetic theory of hard spheres under strong confinement.

The kinetic theory description of a low-density gas of hard spheres or disks, confined between two parallel plates separated at a distance smaller than twice the diameter of the particles, is addressed starting from the Liouville equation of the system. The associated Bogoliubov, Born, Green, Kirkwood, and Yvon hierarchy of equations for the reduced distribution functions is expanded in powers of a parameter measuring the density of the system in the appropriate dimensionless units. The Boltzmann level of description is obtained by keeping only the two lowest orders in the parameter.

A clinical practice review of therapeutic movement-based anterior cruciate ligament reconstruction return to sports bridge program: the biological, biomechanical and behavioral rationale.

This clinical practice review describes the biological, biomechanical and behavioral rationale behind a return to sport bridge program used predominantly with non-elite, youth and adolescent high school and college athletes following anterior cruciate ligament (ACL) reconstruction. Post-physiotherapy, this program has produced outcomes that meet or exceed previous reports. With consideration for athletic identity and the Specific Adaptations to Imposed Demands (SAID) principle, the early program focus was on restoring non-impaired bilateral lower extremity joint mobility and bi-articular musculotendinous extensibility.

Global knee function rating more strongly influences adolescent athletes that sustain a sports-related surgical ACL re-injury or contralateral ACL injury.

Purpose: This study evaluated differences between adolescent athletes who sustained a surgical anterior cruciate ligament (ACL) re-injury, or contralateral ACL injury following return to sports bridge programme participation (Group 1) compared to those that did not (Group 2).

Methods: At 19.9 ± 7 years of age, 198 athletes participated in this study.

Relationship Between Age and Pathology With Treatment of Pediatric and Adolescent Discoid Lateral Meniscus: A Report From the SCORE Multicenter Database.

Background: Surgical treatment options of discoid lateral meniscus in pediatric patients consist of saucerization with or without meniscal repair, meniscocapular stabilization, and, less often, subtotal meniscectomy.

Purpose: To describe a large, prospectively collected multicenter cohort of discoid menisci undergoing surgical intervention, and further investigate corresponding treatment of discoid menisci.

Study Design: Cohort study; Level of evidence, 3.

Age, Sex, and BMI Differences Related to Repairable Meniscal Tears in Pediatric and Adolescent Patients.

Background: The incidence of meniscus tears and ACL tears in pediatric patients continues to rise, bringing to question the risk factors associated with these injuries. As meniscus tears are commonly repaired in pediatric populations, the epidemiology of repairable meniscus tears is an important for consideration for surgeons evaluating treatment options.

Purpose: To describe meniscal tear patterns in pediatric and adolescent patients who underwent meniscal repair across multiple institutions and surgeons, as well as to evaluate the relationship between age, sex, and body mass index (BMI) and their effect on the prevalence, type, and displacement of repaired pediatric meniscal tears.

ACL microtrauma: healing through nutrition, modified sports training, and increased recovery time.

Purpose: Sports injuries among youth and adolescent athletes are a growing concern, particularly at the knee. Based on our current understanding of microtrauma and anterior cruciate ligament (ACL) healing characteristics, this clinical commentary describes a comprehensive plan to better manage ACL microtrauma and mitigate the likelihood of progression to a non-contact macrotraumatic ACL rupture.

Methods: Medical literature related to non-contact ACL injuries among youth and adolescent athletes, collagen and ACL extracellular matrix metabolism, ACL microtrauma and sudden failure, and concerns related to current sports training were reviewed and synthesized into a comprehensive intervention plan.

Meniscus Repair in Pediatric Athletes.

Meniscus tears are common in the pediatric population, typically occur after noncontact injuries, and can be diagnosed clinically with MRI confirmation. Surgery should be offered to patients with loss of range of motion, persistent symptoms, or displaced/complex tears. Given poor long-term outcomes reported after meniscectomy, repair should be attempted when possible as pediatric menisci are well vascularized and have better outcomes after repair than their adult counterparts.

Mosquito species identification using convolutional neural networks with a multitiered ensemble model for novel species detection.

With over 3500 mosquito species described, accurate species identification of the few implicated in disease transmission is critical to mosquito borne disease mitigation. Yet this task is hindered by limited global taxonomic expertise and specimen damage consistent across common capture methods. Convolutional neural networks (CNNs) are promising with limited sets of species, but image database requirements restrict practical implementation.

Effects of interventions for promoting physical activity during recess in elementary schools: a systematic review.

Objective: Summarize the effects of interventions designed to promote physical activity during elementary school recess in children between 5 and 10 years old. Effective school interventions for children can promote physical activity and healthy behaviors.

Methods: PubMed, Scopus, Bireme, SciELO, Web of Science, PsychINFO, Proquest, Physical Education Index, Sports Discus, and Eric databases were included in the data search.

Return to sports bridge program improves outcomes, decreases ipsilateral knee re-injury and contralateral knee injury rates post-ACL reconstruction.

Purpose: To present the results of a return to sports bridge program designed to reduce knee injuries following ACL reconstruction and physical therapy.

Methods: One hundred and fifty (male = 83, female = 67) patients participated in a whole body neuromuscular control, progressive resistance strength and agility training program. Post-program testing included functional movement form, dynamic knee stability, lower extremity power, agility, and sports skill assessments.

Development of a low-cost imaging system for remote mosquito surveillance.

Targeted vector control strategies aiming to prevent mosquito borne disease are severely limited by the logistical burden of vector surveillance, the monitoring of an area to understand mosquito species composition, abundance and spatial distribution. We describe development of an imaging system within a mosquito trap to remotely identify caught mosquitoes, including selection of the image resolution requirement, a design to meet that specification, and evaluation of the system. The necessary trap image resolution was determined to be 16 lp/mm, or 31.

Self-diffusion in a quasi-two-dimensional gas of hard spheres.

A quasi-two-dimensional system of hard spheres strongly confined between two parallel plates is considered. The attention is focused on the macroscopic self-diffusion process observed when the system is seen from above or from below. The transport equation, and the associated self-diffusion coefficient, are derived from a Boltzmann-Lorentz kinetic equation, valid in the dilute limit.

Inhomogeneous cooling state of a strongly confined granular gas at low density.

The inhomogeneous cooling state describing the hydrodynamic behavior of a freely evolving granular gas strongly confined between two parallel plates is studied, using a Boltzmann kinetic equation derived recently. By extending the idea of the homogeneous cooling state, we propose a scaling distribution in which all the time dependence occurs through the granular temperature of the system, while there is a dependence on the distance to the confining walls through the density. It is obtained that the velocity distribution is not isotropic, and it has two different granular temperature parameters associated to the motion perpendicular and parallel to the confining plates, respectively, although their cooling rates are the same.

Understanding an instability in vibrated granular monolayers.

We investigate the dynamics of an ensemble of smooth inelastic hard spheres confined between two horizontal plates separated by a distance smaller than twice the diameter of the particles, in such a way that the system is quasi-two-dimensional. The bottom wall is vibrating and, therefore, it injects energy into the system in the vertical direction and a stationary state is reached. It is found that if the size of the plates is small enough, the stationary state is homogeneous.

Boltzmann kinetic equation for a strongly confined gas of hard spheres.

A Boltzmann-like kinetic equation for a quasi-two-dimensional gas of hard spheres is derived. The system is confined between two parallel hard plates separated a distance between one and two particle diameters. An entropy Lyapunov function for the equation is identified.

Kinetic equation and nonequilibrium entropy for a quasi-two-dimensional gas.

A kinetic equation for a dilute gas of hard spheres confined between two parallel plates separated a distance smaller than two particle diameters is derived. It is a Boltzmann-like equation, which incorporates the effect of the confinement on the particle collisions. A function S(t) is constructed by adding to the Boltzmann expression a confinement contribution.

Shoulder Injuries in Pediatric Athletes.

Shoulder injuries in pediatric athletes are typically caused by acute or overuse injuries. The developing structures of the shoulder lead to injury patterns that are distinct from those of adult athletes. Overuse injuries often affect the physeal structures of the proximal humerus and can lead to pain and loss of sports participation.

Stability analysis of the homogeneous hydrodynamics of a model for a confined granular gas.

The linear hydrodynamic stability of a model for confined quasi-two-dimensional granular gases is analyzed. The system exhibits homogeneous hydrodynamics, i.e.

Anomalous self-diffusion in a freely evolving granular gas near the shearing instability.

The self-diffusion coefficient of a granular gas in the homogeneous cooling state is analyzed near the shearing instability. Using mode-coupling theory, it is shown that the coefficient diverges logarithmically as the instability is approached, due to the coupling of the diffusion process with the shear modes. The divergent behavior, which is peculiar in granular gases and disappears in the elastic limit, does not depend on any other transport coefficient.

Hydrodynamics for a model of a confined quasi-two-dimensional granular gas.

The hydrodynamic equations for a model of a confined quasi-two-dimensional gas of smooth inelastic hard spheres are derived from the Boltzmann equation for the model, using a generalization of the Chapman-Enskog method. The heat and momentum fluxes are calculated to Navier-Stokes order, and the associated transport coefficients are explicitly determined as functions of the coefficient of normal restitution and the velocity parameter involved in the definition of the model. Also an Euler transport term contributing to the energy transport equation is considered.

Power-law decay of the velocity autocorrelation function of a granular fluid in the homogeneous cooling state.

The hydrodynamic part of the velocity autocorrelation function of a granular fluid in the homogeneous cooling state has been calculated by using mode-coupling theory for a finite system with periodic boundary conditions. The existence of the shearing instability, leading to a divergent behavior of the velocity flow fluctuations, is taken into account. A time region in which the velocity autocorrelation function exhibits a power-law decay, when time is measured by the number of collisions per particle, has been been identified.

Homogeneous hydrodynamics of a collisional model of confined granular gases.

The hydrodynamic equation governing the homogeneous time evolution of the temperature in a model of confined granular gas is studied by means of the Enskog equation. The existence of a normal solution of the kinetic equation is assumed as a condition for hydrodynamics. Dimensional analysis implies a scaling of the distribution function that is used to determine it in the first Sonine approximation, with a coefficient that evolves in time through its dependence on the temperature.

Memory effects in the relaxation of a confined granular gas.

The accuracy of a model to describe the horizontal dynamics of a confined quasi-two-dimensional system of inelastic hard spheres is discussed by comparing its predictions for the relaxation of the temperature in a homogenous system with molecular dynamics simulation results for the original system. A reasonably good agreement is found. Next the model is used to investigate the peculiarities of the nonlinear evolution of the temperature when the parameter controlling the energy injection is instantaneously changed while the system was relaxing.

Socioeconomic disparities in work performance following mild stroke.

Purpose: The purpose of this study was to investigate the relationships among the factors that influence return to work for young individuals with mild stroke from different socioeconomic backgrounds.

Methods: Prospective cohort study of working adults with mild stroke (N = 21). Participants completed an assessment battery of cognitive, work environment and work performance measures at approximately 3 weeks and 7 months post mild stroke.

Homogeneous steady state of a confined granular gas.

The nonequilibrium statistical mechanics and kinetic theory for a model of a confined quasi-two-dimensional gas of inelastic hard spheres is presented. The dynamics of the particles includes an effective mechanism to transfer the energy injected in the vertical direction to the horizontal degrees of freedom. The Enskog approximation is formulated and used as the basis to investigate the temperature and the distribution function of the steady state eventually reached by the system.