State laws governing school physical education in relation to attendance and physical activity among students in the USA: A systematic review and meta-analysis

Background:This study systematically synthesized and quantified the relationship linking state laws governing school physical education(PE)to PE attendance and physical activity(PA)in class and throughout the day and week among students in the USA.Methods:A keyword search was performed in PubMed,Web of Science,Cumulative Index to Nursing and Allied Health Literature(CINAHL),Academic Search Complete,and EconLit.Meta-analyses were performed to estimate the effects of state PE laws.Results:A total of 17 studies were included in the review,and five contributed to the meta-analyses.A total of 8 studies used nationally representative school-or student-level data,three focused on multiple states,and the remaining six examined the PE laws of a single state.The presence and strength of state PE laws were positively associated with PE attendance and the frequency and duration of PA during PE classes and throughout the school day.Compared to those residing in states with weak or no PE laws,students in states with strong PE laws had an additional 0.2 days(95%confidence interval(95%CI):0.10.4)of PE attendance per week and spent an additional 33.9 min(95%CI:22.745.0)participating PE classes per week.State PE laws affected girls’PA more than boys’.Different aspects of state PE laws tended to affect students’PE attendance differently.Disparities in the implementation of state PE laws existed across schools.Conclusion:Future studies should adopt objective measures on PE and PA participation and examine the roles schools and districts play in mediating the effect of state PE laws on students’PE attendance and PA.

Timberland Investing and Private Property Rights in the United States of America

Investments in rural land for agriculture, timber, and other natural resource purposes occur frequently and globally. Fundamental principles of liberty and property found in the United States of America’s (“US”) legal system, from its origins to recent US Supreme Court decisions, continue to positively benefit holders of real estate in the Southern US, through a deep-rooted public policy of supporting private property rights and rural economic development. This stable rule of law enhances the long-term adaptability and sustainability of timberland as an asset class. This article is a commentary. It combines legal research methodology with the observations and conclusions of the authors. Its purpose is to demonstrate that the existence of alienable, documentable ownership, and related property rights create inherent stability and security. These principles form the basis of a culture that is defined by the rule of law and is “open for business.” This business mindset is particularly prevalent in the Southern US.

United States Law on the Protection of Abused and Neglected Children

I. Introduction This paper discusses child protection in the United States. I will discuss four general topics. The first topic is United States laws on the protection of children from child abuse and neglect. The second topic is providing care for children who must be removed from their homes. The third is the role of courts in child protection in the United States.

Frictional sliding of infilled planar granite fracture under oscillating normal stress

This paper investigates the frictional behavior of the infilled rock fracture under dynamic normal stress.A series of direct shear tests were conducted on saw-cut granite fractures infilled with quartz using a selfdeveloped dynamic shear apparatus,and the effects of normal load oscillation amplitude,normal load oscillation period and sliding velocity were studied.The test results reveal that the shear response can be divided into three stages over a whole loading-unloading process,characterized by different time spans and stress variations.Generally,a smaller oscillation amplitude,a longer oscillation period and a fast shear velocity promote the stability of the friction system,which is also confirmed by the Coulomb failure criterion calculated based on the observed periodic apparent friction coefficient.The dynamic strengthening/weakening phenomenon is dependent on the oscillation amplitude and product of sliding velocity and oscillation period(vT).Also,the rate and state friction law incorporating the parameter a that characterizes the normal stress variation is employed to describe the dynamic friction coefficient but exhibits an incompetent performance when handling intensive variation in normal stress.Finally,the potential seismicity induced by oscillating normal stress based on the observed stress drop is analyzed.This work helps us understand the sliding process and stability evolution of natural faults,and its benefits for relative hazard mitigation.

Experimental study on the slip evolution of planar fractures subjected to cyclic normal stress

The frictional rupture mechanisms of rock discontinuities considering the dynamic load disturbance still remain unclear.This paper investigates the transitional behaviors of slip events happened on a planar granite fracture under cyclic normal stress with diferent oscillation amplitudes.The experimental results show that the activations of fast slips always correlate with unloading of normal stress.Besides,the intensive normal stress oscillation can weaken the shear strength which is recoverable when the normal stress return to constant.The rupture patterns are quantifed by stress drop,slip length and slip velocity.With the efect of small oscillation amplitudes,the slip events show chaotic shapes,compared to the regular and predictable style under constant normal stress.When the amplitude is large enough,the big and small slip events emerge alternately,showing a compound slip style.Large amplitude of the cyclic normal stress also widens the interval diferences of the slip events.This work provides experimental supports for a convincible link between the dynamic stress disturbance and the slip behavior of rock fractures.

O(t^(-β))-SYNCHRONIZATION AND ASYMPTOTIC SYNCHRONIZATION OF DELAYED FRACTIONAL ORDER NEURAL NETWORKS

This article explores the O(t^(-β))synchronization and asymptotic synchronization for fractional order BAM neural networks(FBAMNNs)with discrete delays,distributed delays and non-identical perturbations.By designing a state feedback control law and a new kind of fractional order Lyapunov functional,a new set of algebraic sufficient conditions are derived to guarantee the O(t^(-β))Synchronization and asymptotic synchronization of the considered FBAMNNs model;this can easily be evaluated without using a MATLAB LMI control toolbox.Finally,two numerical examples,along with the simulation results,illustrate the correctness and viability of the exhibited synchronization results.

The Natural Law of Transition of a Charged Particle into a Compound State under the Action of an Electroscalar Field

This article is the continuation of article [1] where the experimental facts of observation of the electroscalar radiation in the spectrum of the Sun have been presented [2]. This radiation comes into the world having a long wavelength, being longitudinal and extraordinarily penetrating. In accordance with the principle of least action, the Lagrangian of the electroscalar field and the tensor of energy-moment are determined using the variation the potential and coordinates. The equation of motion the charged particle in electroscalar field is determined and the energy of particle has the negative sign with respect to the mechanical energy of particle and the energy of electromagnetic field. So, this is decreasing the electrical potential of particle during the propagation. The electroscalar energy of charged particle and field’s force acting on the particle during their motion change the particle’s electrical status which, in its turn, may trigger the transition of the particle into a compound state during interaction with any object. Due to the continuity this process can lead the particle to the state which enters into a compound state with a negative energy for a different particle’s velocity. This state is the physical vacuum’s state. Analysis of the solar spectrum demonstrates that scattering and absorption of electroscalar wave go on the cavities of solids. The spreading out of electroscalar field obeys to the law of plane wave and the transfer the energy and information can occur in vacuum and any medium.

Extended law of corresponding states for percolation threshold of short-range attractive spheres

The percolation threshold(PT)for colloidal system refers to the point at which particles aggregate to form an infinite cluster that spans the suspension[1].It is widely assumed that the percolation transition should follow the concept of scaling,and recent numerical studies[2-5]have shown that the wrapping probability of percolation can be described by the universal scaling functions,which enables the estimation of PTs for different types of system.

Slow Motion State Assets Law

The sooner the State Assets Law is promulgated,the better state assets will be protected as the reform of state-owned enterprises