Walking-friendly built environments and objectively measured physical function in older adults

BackgroundFew studies have examined the associations between urban design attributes and older adults’ physical function. Especially, it is not well known how built-environment attributes may influence physical function in Asian cities. The aim of this study was to examine associations between objectively measured environmental attributes of walkability and objectively assessed physical function in a sample of Japanese older adults.MethodsCross-sectional data collected in 2013 from 314 older residents (aged 65–84 years) living in Japan were used. Physical function was estimated from objectively measured upper- and lower-body function, mobility, and balance by a trained research team member. A comprehensive list of built-environment attributes, including population density, availability of destinations, intersection density, and distance to the nearest public transport station, were objectively calculated. Walk Score as a composite measure of neighborhood walkability was also obtained.ResultsAmong men, higher population density, availability of destinations, and intersection density were significantly associated with better physical function performance (1-legged stance with eyes open). Higher Walk Score was also marginally associated with better physical function performance (1-legged stance with eyes open). None of the environmental attributes were associated with physical function in elderly women.ConclusionOur findings indicate that environmental attributes of walkability are associated with the physical function of elderly men in the context of Asia. Walking-friendly neighborhoods can not only promote older adults’ active behaviors but can also support their physical function.     

Protective effect of ascorbic acid against oxidative damage induced by hydrogen peroxide in cultured human peripheral blood lymphocytes

Hydrogen peroxide is one of the reactive oxygen species for cellular injury. It is overproduced during oxidative stress and is known to damage proteins, nucleic acids and cell membranes. The present study was aimed to study the protective effect of ascorbic acid against the toxic doses of hydrogen peroxide using lipid peroxidation and cytokinesis blocked micronucleus assay. Hydrogen peroxide was studied at 50, 100 and 200μM and was found to increase a dose dependent increase in lipid peroxidation and micronuclei frequency. The treatment of 100 and 200μM of hydrogen peroxide separately along with 20, 40 and 80μM of ascorbic acid showed a dose dependent decrease in the lipid peroxidation and micronuclei frequency. The results suggest a protective effect of ascorbic acid against the hydrogen peroxide induced oxidative damage in cultured human peripheral blood lymphocytes.     

Fault tolerant cooperative control for affine multi-agent systems: An optimal control approach

The goal of this paper is to propose an optimal fault tolerant control (FTC) approach for multi-agent systems (MASs). It is assumed that the agents have identical affine dynamics. The underlying communication topology is assumed to be a directed graph. The concepts of both inverse optimality and partial stability are further employed for designing the control law fully developed in the paper. Firstly, the optimal FTC problem for linear MASs is formulated and then it is extended to MASs with affine nonlinear dynamics. To solve the Hamilton-Jacobi-Bellman (HJB) equation, an Off-policy Reinforcement Learning is used to learn the optimal control law for each agent. Finally, a couple of numerical examples are provided to demonstrate the effectiveness of the proposed scheme.     

Optimal trajectory tracking solution: Fractional order viewpoint

In this paper, a generalized trajectory tracking problem for a closed-loop control system is formulated in the optimal control context. A linear time varying plant is considered to track a closed-loop desired trajectory generated by a given mechanism. The theoretical results are obtained based on the Hamilton-Jacobi-Bellman theory in which some generalized semiquadratic value functions are employed as the Lagrangian. In addition, we employ a non-integer order integral of Riemann-Liouville type as the cost functional, so that the trajectory tracking process can be evaluated in an extended optimum manner wherein the fractionality plays the main role. By selecting a suitable fractional order of the integral, a satisfactory optimal control system can be deduced in which least concentration on selecting the weighting matrices is needed. To show the effectiveness of the results, some numerical examples illustrate the potentials.     

Robust finite-time stabilizers for five-degree-of-freedom active magnetic bearing system

In this paper, the robust finite-time stabilization problem for a fully suspended five-degree-of-freedom active magnetic bearing system is addressed in the presence of external disturbances and additive uncertainties. By developing the nonsingular terminal sliding mode control and defining new nonlinear sliding surfaces, three separate classes of stabilizers are proposed to regulate and place the suspended rotor in the desired positions of air gaps within adjustable finite times. The suggested nonlinear sliding surfaces and designed control inputs for each class of stabilizers are two major differences between these stabilizers. It is mathematically proven that five control voltages of this system, designed by each class of the suggested stabilizers, are able to locate the suspended rotor at the centers of air gaps in the adjustable finite time which is summation of two reaching and settling finite times. Moreover, several new inequalities are extracted for determining the reaching and settling finite times related to the three classes of stabilizers. These inequalities reveal the dependencies between optional parameters of the proposed stabilizers and the mentioned finite times. Finally, numerical simulations are provided to illustrate the efficiency and good performance of each class of the designed stabilizers.     

Prevalence of reading failure in boys compared with girls

The hypothesis that proportionately more boys than girls experience reading failure was tested on a sample of 708 children using both test-identified and teacher-identified criteria. Test-identified reading failure was defined by low scores on standardized reading achievement tests given at the end of first and third grade. For Severely Reading Disabled (total reading score at the 10th percentile or lower), the ratio of boys to girls was 1.4:1 at first grade and 1.3:1 at third. At both grades equal proportions of boys and girls were represented in the Reading Disabled category (total reading score between the 11th and 30th percentile). Teacher-identified reading failure criteria consisted of enrollment in LD and Chapter One (remedial reading) programs at first and third grades. Teacher-identified ratios of boys to girls in LD were 2:1 at both first and third grade, exceeding the test-identified ratios, while identification for Chapter One services did not show a gender difference.     

EFL teachers’ conceptions of speaking competence in English

The present article lies at the intersection of research on teacher cognition and speaking competence in a second language. It is a qualitative analysis of teacher accounts of speaking in the context of English as a foreign language (EFL) in Iran. More specifically, the study is an exploration of three EFL teachers’ conceptions of learning and teaching the speaking skill in English. The teachers represented varying levels of experience and education and were classified as experts and novices. Through juxtaposing teachers’ views of how students should learn to speak and how the teachers themselves learned to speak English, the research study uncovers the interwoven nature of learning experience with teaching conceptions. It also unveils the images underpinning their conceptions of how to learn and teach speaking in an EFL context. The results also portray teachers as having unique ways of thinking of speaking while at the same time sharing certain patterns.     

The significance of troponin T and CK-MB release in coronary artery bypass surgery

Measurement of cardiac markers is an index of care standard in the assessment and diagnosis of cardiovascualr disease. Two of the major cardiac markers are Creatine Kinase isoenzyme CK-MB and Troponin T, which are extensively used in the diagnosis of heart disease. The release of Troponin T and creatine kinase isoenzyme (CK-MB) was investigated in 50 coronary artery bypass surgery patients. Measurement of plasma samples was carried out at five different time points, namely before surgery, 1,6,12,24 hours after surgery. The results indicated that CK-MB level were increased by a factor more than four times compared with the upper limit of baseline (befor surgery). Troponin T concentration showed more than six fold over the upper limit of baseline (before surgert) at 1,6,12,24 hours after surgery. In order to assess the significance of the length of the surgical procedure on the release of Troponin T and CK-MB, the surgery patient were divided into two groups according to the length of the surgical procedure: group I was selected on the basis that the surgical procedure they underwent lasted above 90 minutes and group II with a surgical procedure below 90 minutes. Both Troponin T and CK-MB showed a significant increase in-group I compared to group II. To investigate the likelihood that this effect is party due to myocardial infarction during surgery, the patients were divided into two groups: Group A with some sings of myocardial infarction on Q wave of ECG and group B without any change. The results showed approximately a two-fold increase of these markers in-group A compared to group B. Since these markers reach into blood following damage to myocardial their increase in patients with time course surgery of more than 90 minutes and those with a probability of MI during operation, indicating that these patient fall into a high risk group of repeat (MI) after surgery.     

Finite-time stability analysis and stabilization for linear discrete-time system with time-varying delay

The problem of finite-time stability for linear discrete-time systems with time-varying delay is studied in this paper. In order to deal with the time delay, the original system is firstly transformed into two interconnected subsystems. By constructing a delay-dependent Lyapunov–Krasovskii functional and using a two-term approximation of the time-varying delay, sufficient conditions of finite-time stability are derived and expressed in terms of linear matrix inequalities (LMIs). The derived stability conditions can be applied into analyzing the finite-time stability and deriving the maximally tolerable delay. Compared with the existing results on finite-time stability, the derived stability conditions are less conservative. In addition, for the stabilization problem, we design the state-feedback controller. Finally, numerical examples are used to illustrate the effectiveness of the proposed method.     

Student achievement conditioned upon school selection: Religious and secular secondary school quality in Bangladesh

In this paper we present new evidence on the impact of school characteristics on secondary student achievement using a rich dataset from rural Bangladesh. We deal with a potentially important selectivity issue in the South Asian context: the non-random sorting of children into madrasas (Islamic faith schools). We do so by employing a combination of fixed effects and instrumental variable estimation techniques. Our empirical results do not reveal any difference in test scores between religious and secular schools when selection into secondary school is taken into account. However, we document significant learning deficit by gender and primary school type: girls and graduates of primary madrasas have significantly lower test scores even after controlling for school and classroom-specific unobservable correlates of learning.