Correlates of Vitamin D Status in Healthy Older Adults Living in Miami-Dade and its Association with Non-Skeletal Outcomes: A Cross-Sectional Study

Examining factors that affect vitamin D status in the fast-growing elderly population of Miami-Dade, Florida, is needed. Vitamin D deficiency in older adults has been linked to correlates of disability, including falls and fractures, and cardiovascular disease. The purpose of this study was to determine the proportion of vitamin D insufficient individuals and their relationship with vitamin D insufficiency in older adults (n=97) living in Miami-Dade. We evaluated the association between vitamin D status and 1) dual task physical performance to understand the link between vitamin D and cognition in the context of mobility; and 2) cardiometabolic risk, measured by galvanic skin response, pulse oximetry, and blood pressure to create a composite score based on autonomic nervous system and endothelial function. Participants completed baseline assessments that included serum levels of vitamin D, anthropometrics, body composition, dual task physical performance and cardiometabolic risk. Surveys to evaluate vitamin D intake, sun exposure, physical activity, and depressive symptoms were completed. Spearman’s correlations, independent t-tests, paired t-tests, repeated measures ANOVAs, and multiple logistic and linear regressions were used to examine the relationship of vitamin D insufficiency (25(OH)D /ml) and sufficiency (25(OH)D ≥30 ng/ml) with determinants of vitamin D status, dual task physical performance variables and cardiometabolic risk scores. Although the proportion of vitamin D insufficient individuals was lower when compared to the prevalance of the general United States elderly population, it was still common in healthy community-dwelling older adults living in Miami-Dade County, especially among Hispanics. Factors that affected skin synthesis (ethnicity, and sun exposure), and bioavailability/metabolism (obesity) were significant predictors of vitamin D status. Vitamin D insufficiency was not significantly correlated with worse dual task physical performance; however, cognitive performance was worse in the vitamin D insufficient group. Our results suggest a relationship of vitamin D insufficiency with executive dysfunction, and support an association with cardiometabolic risk using an innovative electro-sensor complex, possibly by modulating autonomic nervous system activity and vascular function, thus affecting cardiac performance.

Impact d’une supplémentation protéino-énergétique sur les performances physiques en réadaptation chez la personne âgée traumatisée crânienne : un projet pilote

L’exacerbation de la perte d’autonomie des personnes âgées hospitalisées est fréquente. Le traumatisme craniocérébral (TCC) est une condition médicale associée à un état de stress et d’hypercatabolisme particulièrement élevé (Cook, 2008) qui rend la personne âgée encore plus vulnérable. De plus, les recommandations en vigueur pour l’apport protéique (0,8 g/kg) semblent insuffisantes pour freiner la perte de masse musculaire qui conduit à la sarcopénie. L’objectif de cette étude était de déterminer l’impact d’un supplément protéino-énergétique sur les performances physiques de la personne âgée traumatisée crânienne en réadaptation, plus spécifiquement sur la distance de marche, la force de préhension, ainsi que le test du « Time up and go » (TUG). Vingtquatre sujets, âgés de 65 à 94 ans (14 hommes) ont consenti à participer à cette étude randomisée contrôlée à double-aveugle dans un centre de réadaptation fonctionnelle intensive à Montréal. L’intervention consistait à ingérer un supplément nutritionnel (230 kcal, 15 g protéines, 25 g glucides) ou un placebo immédiatement après le traitement régulier de physiothérapie (45 à 60 minutes, 4 à 5 fois par semaine). Aucune différence significative n’a été trouvée dans les caractéristiques de base des 2 groupes. Une amélioration significative a été trouvée dans le groupe supplément pour le test du TUG. Notre étude d’intervention est la première en nutrition en sol québécois dans les Centres de réadaptation. La consommation d’un supplément chez la personne âgée durant le traitement de physiothérapie est une mesure simple et facile à introduire dans un contexte clinique. Même en l’absence de gains significatifs sur l’ensemble des mesures physiques, le supplément nutritionnel permet d’augmenter les apports caloriques et protéiques, ce qui peut contribuer à optimiser l’état nutritionnel. La littérature documente largement les impacts négatifs de la malnutrition et toute mesure pouvant contribuer à diminuer la prévalence de cette dernière ne peut donc qu’être positive.

Concurrent validity of the Swedish version of the life-space assessment questionnaire

BACKGROUND: The Life-Space Assessment (LSA), developed in the USA, is an instrument focusing on mobility with respect to reaching different areas defined as life-spaces, extending from the room where the person sleeps to mobility outside one's hometown. A newly translated Swedish version of the LSA (LSA-S) has been tested for test-retest reliability, but the validity remains to be tested. The purpose of the present study was to examine the concurrent validity of the LSA-S, by comparing and correlating the LSA scores to other measures of mobility. METHOD: The LSA was included in a population-based study of health, functioning and mobility among older persons in Sweden, and the present analysis comprised 312 community-dwelling participants. To test the concurrent validity, the LSA scores were compared to a number of other mobility-related variables, including the Short Physical Performance Battery (SPPB) as well as "stair climbing", "transfers", "transportation", "food shopping", "travel for pleasure" and "community activities". The LSA total mean scores for different levels of the other mobility-related variables, and measures of correlation were calculated. RESULTS: Higher LSA total mean scores were observed with higher levels of all the other mobility related variables. Most of the correlations between the LSA and the other mobility variables were large (r = 0.5-1.0) and significant at the 0.01 level. The LSA total score, as well as independent life-space and assistive life-space correlated with transportation (0.63, 0.66, 0.64) and food shopping (0.55, 0.58, 0.55). Assistive life-space also correlated with SPPB (0.47). With respect to maximal life-space, the correlations with the mobility-related variables were generally lower (below 0.5), probably since this aspect of life-space mobility is highly influenced by social support and is not so dependent on the individual's own physical function. CONCLUSION: LSA was shown to be a valid measure of mobility when using the LSA total, independent LS or assistive LSA.

Asociación de las violencias física, sexual y comunitaria con el embarazo en adolescentes: análisis multinivel

Objetivos Determinar si existe asociación entre la exposición a violencia, experimentada a nivel individual o municipal, y el embarazo adolescente en mujeres Colombianas entre 13 y 19 años de edad que contestaron la Encuesta de Demografía y Salud en el año 2010. Métodos Estudio de corte transversal, nacional y multinivel. Se tomaron datos de dos niveles jerárquicos: Nivel- 1: Datos individuales de una muestra representativa de 13.313 mujeres entre 13 y 19 años de edad provenientes de La Encuesta Nacional de Demografía y Salud del año 2010 y Nivel- 2: Datos municipales de 258 municipios provenientes de las estadísticas vitales del DANE. Resultados La prevalencia del embarazo adolescente fue del 16.8% IC 95% [16.2-17.4]. El análisis mostró que la asociación entre embarazo adolescente y violencia tanto individual, representada como violencia sexual [OR= 6.99 IC99% 4.80-10.10] y violencia física [OR= 1.74 IC99% 1.47-2.05] así como la violencia municipal medida con tasas de homicidios altas [OR= 1.99 IC99% 1.29-3.07] y muy altas [OR= 2.10 IC99% 1.21-3.61] se mantuvo estadísticamente significativa después de ajustar por las variables: Edad [OR= 1.81 IC99% 1.71-1.91], ocupación [OR= 1.62 IC99% 1.37-1.93], educación primaria o sin educación [OR= 2.20 IC99% 1.47-3.30], educación secundaria [OR= 1.70 IC99% 1.24-2.32], asistir al colegio [OR= 0.18 IC99% 0.15-0.21], conocimiento en la fisiología reproductiva [OR= 1.28 IC99% 1.06-1.54], el índice de riqueza Q1, Q2, Q3 [OR= 2.18 IC99% 1.42-3.34], [OR= 2.00 IC99% 1.39-2.28], [OR= 1.82 IC99% 1.92-2.25] y alto porcentaje de Necesidades básicas insatisfechas a nivel municipal [OR= 2.34 IC99% 1.55-3.52]. Conclusiones Este estudio mostró una relación significativamente estadística entre la violencia sexual y física con el inicio de relaciones sexuales y embarazo adolescente después de controlar por factores sociodemográficos y conocimientos en reproducción sexual en mujeres colombianas de 13 a 19 años en el año 2010. Esta asociación debe continuar siendo estudiada para lograr optimizar las estrategias de prevención y disminuir la tasa actual de embarazos adolescentes en el país y sus consecuencias.

Weight bearing physical activity for performance and bone health in prepubertal girls

This study assessed the status of bone and cardiovascular health in young, prepubertal females (aged 9 to 11 years) during a school based intervention program involving weight bearing physical activity. A study of 10 months duration was conducted in four primary schools in the Melbourne suburbs. It involved a physical activity group (n=38) and an aged-matched control group (n=33). Baseline data including pubertal status, health-related fitness, bone mass and body composition were obtained pre and post the intervention programme. All children had their bone mineral density monitored. Bone mineral density and body composition measurements were performed by DXA using the Hologic QDR 2000 bone densitometer. At the completion of the program the activity group had accrued significantly greater bone mass at total body, lumbar spine, leg and femoral neck when expressed as BMC or BMD.

Performance analysis of adaptive physical layer network coding for wireless two-way relaying

The performance analysis of adaptive physical layer network-coded two-way relaying scenario is presented which employs two phases: Multiple access (MA) phase and Broadcast (BC) phase. The deep channel fade conditions which occur at the relay referred as the singular fade states fall in the following two classes: (i) removable and (ii) non-removable singular fade states. With every singular fade state, we associate an error probability that the relay transmits a wrong network-coded symbol during the BC phase. It is shown that adaptive network coding provides a coding gain over fixed network coding, by making the error probabilities associated with the removable singular fade states contributing to the average Symbol Error Rate (SER) fall as SNR-2 instead of SNR-1. A high SNR upper-bound on the average end-to-end SER for the adaptive network coding scheme is derived, for a Rician fading scenario, which is found to be tight through simulations. Specifically, it is shown that for the adaptive network coding scheme, the probability that the relay node transmits a wrong network-coded symbol is upper-bounded by twice the average SER of a point-to-point fading channel, at high SNR. Also, it is shown that in a Rician fading scenario, it suffices to remove the effect of only those singular fade states which contribute dominantly to the average SER.

Performance analysis of adaptive physical layer network coding for wireless two-way Relaying

The analysis of modulation schemes for the physical layer network-coded two way relaying scenario is presented which employs two phases: Multiple access (MA) phase and Broadcast (BC) phase. Depending on the signal set used at the end nodes, the minimum distance of the effective constellation seen at the relay becomes zero for a finite number of channel fade states referred as the singular fade states. The singular fade states fall into the following two classes: (i) the ones which are caused due to channel outage and whose harmful effect cannot be mitigated by adaptive network coding called the non-removable singular fade states and (ii) the ones which occur due to the choice of the signal set and whose harmful effects can be removed called the removable singular fade states. In this paper, we derive an upper bound on the average end-to-end Symbol Error Rate (SER), with and without adaptive network coding at the relay, for a Rician fading scenario. It is shown that without adaptive network coding, at high Signal to Noise Ratio (SNR), the contribution to the end-to-end SER comes from the following error events which fall as SNR-1: the error events associated with the removable and nonremovable singular fade states and the error event during the BC phase. In contrast, for the adaptive network coding scheme, the error events associated with the removable singular fade states fall as SNR-2, thereby providing a coding gain over the case when adaptive network coding is not used. Also, it is shown that for a Rician fading channel, the error during the MA phase dominates over the error during the BC phase. Hence, adaptive network coding, which improves the performance during the MA phase provides more gain in a Rician fading scenario than in a Rayleigh fading scenario. Furthermore, it is shown that for large Rician factors, among those removable singular fade states which have the same magnitude, those which have the least absolute value of the phase - ngle alone contribute dominantly to the end-to-end SER and it is sufficient to remove the effect of only such singular fade states.

PHYSICAL AGING OF HIGH-PERFORMANCE THERMOPLASTICS - ENTHALPY RELAXATION IN PEK-C AND PES-C

The developments of physical aging in phenolphthalein poly(aryl-ether-ketone) (PEK-C) and poly(aryl-ether-sulfone) (PES-C) with time at two aging temperatures up to 20 K below their respective glass transition temperatures (T-g = 495 and 520 K) have been studied using differential scanning calorimetry (DSC). Substantial relaxation within the aging course of several hours were observed by detecting T-g decreasing during physical aging process at the two aging temperatures. The relaxation processes of both polymers are extremely nonlinear and self-retarding. The time dependencies of their enthalpies during the initial stages of annealing were approximately modeled using the Narayanaswamy-Tool model. The structure relaxation parameters obtained from this fitting were used to predict the possibility of physical aging occurring at their respective using temperatures. (C) 1995 John Wiley and Sons, Inc.

An Antennas and Propagation Approach to Improving Physical Layer Performance in Wireless Body Area Networks

A combined antennas and propagation study has been undertaken with a view to directly improving link conditions for wireless body area networks. Using tissue-equivalent numerical and experimental phantoms representative of muscle tissue at 2.45 GHz, we show that the node to node [S-21] path gain performance of a new wearable integrated antenna (WIA) is up to 9 dB better than a conventional compact Printed-F antenna, both of which are suitable for integration with wireless node circuitry. Overall, the WIA performed extremely well with a measured radiation efficiency of 38% and an impedance bandwidth of 24%. Further benefits were also obtained using spatial diversity, with the WIA providing up to 7.7 dB of diversity gain for maximal ratio combining. The results also show that correlation was lower for a multipath environment leading to higher diversity gain. Furthermore, a diversity implementation with the new antenna gave up to 18 dB better performance in terms of mean power level and there was a significant improvement in level crossing rates and average fade durations when moving from a single-branch to a two-branch diversity system.

Making geography mobile: using location aware technology to improve student performance in physical geography

With the increased availability of new technologies, geography educators are revisiting their pedagogical approaches to teaching and calling for opportunities to share local and international practices which will enhance the learning experience and improve students’ performance. This paper reports on the use of handheld mobile devices, fitted with GPS, by secondary (high) school pupils in geography. Two location-aware activities were completed over one academic year (one per semester) and pre-test and post-test scores for both topics revealed a statistically significant increase in pupils’ performance as measured by the standard national assessments. A learner centred educational approach was adopted with the first mobile learning activity being created by the teacher as an exemplar of effective mobile learning design. Pupils built on their experiences of using mobile learning when they were required to created their own location aware learning task for peer use. An analysis of the qualitative data from the pupils’ journals, group diaries and focus group interviews revealed the five pillars of learner centred education are addressed when using location aware technologies and the use of handheld mobile devices offered greater flexibility and autonomy to the pupils thus altering the level of power and control away from the teacher. Due to the relatively small number of participants in the study, the results are more informative than generalisable however in light of the growing interest in geo-spatial technologies in geography education, this paper offers encouragement and insight into the use of location aware technology in a compulsory school context

Physical Layer Secrecy Performance over Rayleigh/Rician Fading Channels

In this paper, we investigate the physical layer secrecy performance of a single-input single-output system that consists of single antenna devices and operates in the presence of a single antenna passive eavesdropper over dissimilar fading channels. In particular, we consider two scenarios in terms of dissimilar fading channel arrangements: the legal/illegal channels are subject to Rayleigh/Rician fading, respectively; and the legal/illegal channels are subject to Rician/Rayleigh fading, respectively. Specifically, analytical expressions for the probability of the existence of a non-zero secrecy capacity and the secrecy outage probability are derived by using statistical characteristics of the signal-to-noise ratio. Numerical results are provided for selected scenarios to illustrate applications of the developed analytical expressions.

Mediating Influence of Physical Fitness on the Relationship between Academic Performance and Motor Proficiency

We explored the potential mediating influence of physical fitness on the relationship between academic performance and motor proficiency in children. 1864 students (F:926, M:938, age 11.91 (SD:0.34). Academic achievement was derived from an average of standardized tests of reading, writing, and math. The Bruininks-Oseretsky Test of Motor Performance (short-form) determined motor proficiency. Fitness (peak oxygen uptake) was established with the Léger 20-m Shuttle Run Test. OLS regression identified several significant predictors of academic performance. After controlling for age (p=0.0135), gender (p<0.0001), and parental education (p<0.0001), motor proficiency (p<0.0001), was significant. After adding physical fitness (p=0.0030) to the model the effect of motor proficiency remained significant however the point estimate was reduced from 0.0034 (p<0.0001) to 0.0026 (p<0.0001). These results suggest that physical fitness plays a mediating role on the relationship between academic performance and motor proficiency although both aerobic fitness and motor proficiency have independent roles.

The impact of social competence between physical activity and motor performance

Objective: To identify the association of low physical activity (PA) participation in children with various motor performances (MP) and to establish the impact of social competence (SC). Methods: Sixth grade children from PHAST study at Brock University (n=1958; 50.53% males) had MP test results from Bruininks-Oseretsky Test of Motor Proficiency, Participation Questionnaire (PQ) used for PA and Harter Social Competence Scale for self-perceived SC. Comparative tests, multiple and logistic regressions were performed. Results: Significant differences in PQ measures in MP quartiles and SCs. MP and SC are independent predictors of PA (p<.05) except with SES on free play activity, making MP not significant. Lower MP increased the odds of low total PA and organized sport participation but not for free play activities (OR~1). Higher SC reduced the risk of low participation in all PA measures. Conclusions: SC improves PA participation, including free play and organized sports, despite the child’s MP.