The impact of retirement on physical activity

Most adults do not achieve the levels of physical activity currently recommended for a healthy lifestyle. Population surveys suggest that there is a linear decline of activity levels with age, yet physical activity has many health benefits for older adults. If these are to be more widely adopted among older people, health policy and promotion require an understanding of the factors that influence decreasing activity with age. This study examined the patterns of physical activity of 699 participants in the West of Scotland Twenty-07 Study who were aged 60 years when interviewed in 1991 and followed up four to five years later. It examined the factors that influenced whether or not the subjects achieved currently recommended levels of activity, by applying random effects models with a seasonal adjustment. It was found that higher levels of physical activity associated with a healthier lifestyle, and that socio-economic factors played a minor role in determining the level of physical activity. A substantial amount of physical activity occurred at work but was lost by those who had retired, for while those who were not working were more physically active at home or at leisure than those in work, the majority of the sample did too little physical activity outside work to compensate for the loss of work-based activity. One conclusion is that health promotion initiatives that encourage people to become more physically active should be targeted at those who are about to retire

A Modified Version of the Waxman Algorithm

The iterative algorithm recently proposed by Waxman for solving eigenvalue problems, which relies on the method of moments, has been modified to improve its convergence considerably without sacrificing its benefits or elegance. The suggested modification is based on methods to calculate low-lying eigenpairs of large bounded hermitian operators or matrices

An algorithmic approach to the existence of ideal objects in commutative algebra

The existence of ideal objects, such as maximal ideals in nonzero rings, plays a crucial role in commutative algebra. These are typically justified using Zorn's lemma, and thus pose a challenge from a computational point of view. Giving a constructive meaning to ideal objects is a problem which dates back to Hilbert's program, and today is still a central theme in the area of dynamical algebra, which focuses on the elimination of ideal objects via syntactic methods. In this paper, we take an alternative approach based on Kreisel's no counterexample interpretation and sequential algorithms. We first give a computational interpretation to an abstract maximality principle in the countable setting via an intuitive, state based algorithm. We then carry out a concrete case study, in which we give an algorithmic account of the result that in any commutative ring, the intersection of all prime ideals is contained in its nilradical

Noctilucent clouds and the mesospheric water vapour: The past decade

The topic of this paper is the sensitivity of the brightness of noctilucent clouds (NLC) on the ambient water vapour mixing ratio f(H2O). Firstly, we use state-of-the-art models of NLC layer formation to predict NLC brightness changes in response to changes in the 80km mixing ratio f(H2O) for the two cases of ground-based 532nm lidar observations at 69° N and for hemispheric satellite SBUV observations at 252nm wavelength. In this study, we include a re-evaluation of the sensitivity of NLC brightness to changes in solar Lyman α flux. Secondly, we review observations of episodic changes in f(H2O) and those in NLC brightness, the former being available since 1992, the latter since 1979. To this review, we add a new series of observations of f(H2O), performed in the Arctic summer at the ALOMAR observatory. The episodic change exhibited by the Arctic summer means of f(H2O) turns out to be quite different from all those derived from annual means of f(H2O). The latter indicate that since 1996 a significant reduction of annually averaged upper mesospheric water vapour has occurred at low, mid, and high latitudes. These decreases of f(H2O) have been observed over the same time period in which a slow increase of SBUV NLC albedo has occurred. From this scenario and additional arguments we conclude that the cause for the observed long-term increase in NLC albedo remains to be identified. We close with comments on the very different character of decadal variations in NLC brightness and occurrence rate

Spatio-Temporal Scaling of Solar Surface Flows

The Sun provides an excellent natural laboratory for nonlinear phenomena. We use motions of magnetic bright points on the solar surface, at the smallest scales yet observed, to study the small scale dynamics of the photospheric plasma. The paths of the bright points are analyzed within a continuous time random walk framework. Their spatial and temporal scaling suggest that the observed motions are the walks of imperfectly correlated tracers on a turbulent fluid flow in the lanes between granular convection cells.Comment: Now Accepted by Physical Review Letter

A new description of probability density distributions of polar mesospheric clouds

In this paper we present a new description of statistical probability density functions (pdfs) of polar mesospheric clouds (PMCs). The analysis is based on observations of maximum backscatter, ice mass density, ice particle radius, and number density of ice particles measured by the ALOMAR Rayleigh-Mie-Raman lidar for all PMC seasons from 2002 to 2016. From this data set we derive a new class of pdfs that describe the statistics of PMC events that is different from previous statistical methods using the approach of an exponential distribution commonly named the g distribution. The new analysis describes successfully the probability distributions of ALOMAR lidar data. It turns out that the former g-function description is a special case of our new approach. In general the new statistical function can be applied to many kinds of different PMC parameters, e.g., maximum backscatter, integrated backscatter, ice mass density, ice water content, ice particle radius, ice particle number density, or albedo measured by satellites. As a main advantage the new method allows us to connect different observational PMC distributions of lidar and satellite data, and also to compare with distributions from ice model studies. In particular, the statistical distributions of different ice parameters can be compared with each other on the basis of a common assessment that facilitates, for example, trend analysis of PMC. © Author(s) 2019

Nuclear recoil measurements in Superheated Superconducting Granule detectors

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70Me$\!$V neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few ke$\!$V. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20$\mu$m in diameter will be discussed. For the first time, recoil energy thresholds of $\sim$1ke$\!$V have been measured.Comment: 7pages in Latex format, Preprint Bu-He 93/6 (University of Berne, Switzerland), four figures available upon request via [email protected] or [email protected]

Prevalence and sociodemographic determinants of adult obesity: A large representative household survey in a resource-constrained African setting with double burden of undernutrition and overnutrition

BACKGROUND The obesity epidemic has continued to spread across the globe involving even poor nations of the world. METHOD Household population survey of adults aged 20-60 years. Multistage stratified cluster randomised sampling involving both urban and rural statewide representative population samples. Anthropometric measurements were taken using standard methods. Prevalences were weighted and multinomial regression analyses were done. RESULTS A total of 6628 individuals from 2843 households were surveyed. The weighted overall prevalence for underweight was 9.1% (95% CI 8.1 to 10.1), 65.1% (95% CI 63.6 to 66.6) for normal weight, 19.0% (95% CI 17.8 to 20.3) for overweight and 6.8% (95% CI 6.0 to 7.5) for obese. Men were less likely to be overweight (adjusted OR (AOR) 0.79; 95% CI 0.68 to 0.92) and obese (AOR 0.24; 95% CI 0.19 to 0.31) than women. Urban residents were more likely to be overweight (AOR 1.42; 95% CI 1.18 to 1.71) and obese (AOR 2.09; 95% CI 1.58 to 2.76) than rural residents. Each additional 1-year increase in age increased the risk of overweight by 1.012 (AOR 1.012; 95% CI 1.005 to 1.018) and that of obesity by 1.03 (AOR 1.03; 95% CI 1.02 to 1.04). The low-income class was less likely to be overweight (AOR 0.694; 95% CI 0.507 to 0.951) and obese (AOR 0.44; 95% CI 0.28 to 0.67). CONCLUSION The prevalence of obesity and overweight in Enugu Nigeria is high and fast approaching that of underweight. Women, urban dwellers, older adults and high-income earners are at higher risk for obesity and overweight. The study provides robust information for public health policies towards the prevention of obesity in Nigeria

Flaring Up All Over -- Radio Activity in Rapidly-Rotating Late-Type M and L Dwarfs

We present Very Large Array observations of twelve late M and L dwarfs in the Solar neighborhood. The observed sources were chosen to cover a wide range of physical characteristics - spectral type, rotation, age, binarity, and X-ray and H\alpha activity - to determine the role of these properties in the production of radio emission, and hence magnetic fields. Three of the twelve sources, TVLM513-46546, 2MASS J0036159+182110, and BRI0021-0214, were observed to flare and also exhibit persistent emission, indicating that magnetic activity is not quenched at the bottom of the main sequence. The radio emission extends to spectral type L3.5, and there is no apparent decrease in the ratio of flaring luminosities to bolometric luminosities between M8-L3.5. Moreover, contrary to the significant drop in persistent H\alpha activity beyond spectral type M7, the persistent radio activity appears to steadily increase between M3-L3.5. Similarly, the radio emission from BRI0021-0214 violates the phenomenological relations between the radio and X-ray luminosities of coronally active stars, hinting that radio and X-ray activity are also uncorrelated at the bottom of the main sequence. The radio active sources that have measured rotational velocities are rapid rotators, Vsin(i)>30 km/sec, while the upper limits on radio activity in slowly-rotating late M dwarfs (Vsin(i)<10 km/sec) are lower than these detections. These observations provide tantalizing evidence that rapidly-rotating late M and L dwarfs are more likely to be radio active. This possible correlation is puzzling given that the observed radio emission requires sustained magnetic fields of 10-1000 G and densities of 10^12 cm^-3, indicating that the active sources should have slowed down considerably due to magnetic braking.Comment: Accepted to ApJ; Two new figures; Minor text revision