1,588 research outputs found

    Intake of Fruits, Vegetables, and Sugar-Sweetened Beverages among a Sample of Children in Rural Northern Ontario, Canada

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    There is evidence to suggest that dietary intake of children differs by rural/urban place of residence: rural children may have a higher intake of foods high in fat and sugar than those living in urban environments. The aim of this study was to examine the intake of fruits and vegetables (FV) and the frequency of sugar-sweetened beverage (SSB) consumption, among a sample of rural children in Northern Ontario, Canada, in two different seasons. Sociodemographic factors and children’s FV and SSB intake were measured using two repeated cross-sectional surveys, and seasonal information was based on the month of data collection. Logistic regressions were used to examine the odds of children eating five or more FVs, and the odds of ‘frequently or always’ consuming SSBs. During the fall, children reported eating five or more FV more often, when compared to winter (53.9% vs. 48.3%). In the fall, 25.8% of children reported ‘frequently or always’ drinking SSB, compared with 16.9% in winter. Indigenous children were less likely to eat five or more FV (OR 0.34 (95% CI 0.12–0.95)) in the fall when compared to non-Indigenous children. Findings indicate that intake of FV among rural students in this region is low, and the frequency of SSB is high, when compared with national recommendations

    PVA/ alginate/ tannic acid crosslinked aerogels with low flammability and high mechanical resistance

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    Aerogels are ultra-light, highly porous materials derived from gels in which the solvent has been replaced by gas. Aerogels based on renewable and biodegradable materials are gained attention as environmentally friendly alternatives to conventional foam [1]. This study focuses on the mechanical, thermal, and combustion behavior of a polyvinyl alcohol (PVA), sodium alginate (SA) and tannic acid (TA) aerogel obtained by freeze-drying and ion crosslinking (Ca2+ and B - ). Aerogels containing 5g of PVA, 3g of TA, and 2g of SA exhibit the highest compressive resistance, which was increased by 30% after crosslinking (87.4 MPa/gcm -3 ). In comparison to pure PVA, the addition of TA and SA to the blends decreased its thermal degradation rate. The crosslinking further contributed to an 81% of reduction of the degradation rate (0.16 %/ÂșC) making samples high thermally stable. Regarding flammability samples burnt after being exposed to radiation due to the presence of the highly combustible PVA. However, the heat release rate (HRR) and fire growth (FIGRA) parameters decreased by 67% and 50% respectively when TA and SA was added to pure PVA aerogel. After crosslinking, an additional decrement of 35% in HRR and 54% in FIGRA respectively was obtained (76 kW/m2 and 1.96 kW/m2 s), which corresponds to a very low flame intensity. These results are down below of previous values reported by Wu et al.[2], who worked on PVA/SA crosslinking aerogels filled with inorganic montmorillonite. Hence, the cross-linked aerogels presented here can be considered a very promising sustainable alternative to conventional fossil-derived foams

    Examining factors of accelerometer-measured sedentary time in a sample of rural Canadian children

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    The aim of this study was to examine potential child-level and day-level factors of accelerometer-measured sedentary time in a sample of rural Canadian children. Children (n = 86) from rural Northwestern Ontario participated in this study. Children’s sedentary times were identified and logged using an accelerometer. Child-level data (socio-demographic, household, and environment) came from surveys of children and their parents and a passively logging global positioning unit. Day-level data on day type (weekday/weekend) and weather (temperature, precipitation) were based on the dates of data collection and meteorological data came from the closest Environment Canada weather station. Cross-classified regression models were used to assess the relationship between child-level and day-level correlates of sedentary time. Boys were less sedentary than girls (b = −30.53 p = 0.01). For each one-year age increase, children’s sedentary time increased (b = 12.79 p \u3c 0.01). This study indicates a difference in sedentary time based on a child’s age and gender. However, family, environmental, and weather characteristics did not influence sedentary time in this sample. Health practitioners who deliver care for northern rural youth can provide targeted health advice regarding sedentary time and consider gender and age to be risk factors for these behaviors

    Occupation time limits of inhomogeneous Poisson systems of independent particles

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    We prove functional limits theorems for the occupation time process of a system of particles moving independently in RdR^d according to a symmetric α\alpha-stable L\'evy process, and starting off from an inhomogeneous Poisson point measure with intensity measure ÎŒ(dx)=(1+∣x∣γ)−1dx,Îł>0\mu(dx)=(1+|x|^{\gamma})^{-1}dx,\gamma>0, and other related measures. In contrast to the homogeneous case (Îł=0)(\gamma=0), the system is not in equilibrium and ultimately it vanishes, and there are more different types of occupation time limit processes depending on arrangements of the parameters Îł,d\gamma, d and α\alpha. The case Îł<d<α\gamma<d<\alpha leads to an extension of fractional Brownian motion.Comment: 22 page

    Measuring temporal differences in rural canadian children’s moderate-to-vigorous physical activity

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    The purpose of this study was to measure the factors that influence children’s moderate-to-vigorous physical activity (MVPA) during school curriculum time, recess time, and outside school time in a rural area. During the Fall and Winter of 2016, 34 boys and 55 girls aged 8–14 years from rural communities in rural Northwestern Ontario participated in the Spatial Temporal Environment and Activity Monitoring project. The children’s MVPA was measured using an accelerometer, and child-level demographic, behavioral, and environmental data were gathered from surveys, passively logging global positioning units, and municipal datasets. Data on daily temperature and precipitation were gathered from the closest Environment Canada weather station. A mixed model was used to assess the relationship between child-and day-level factors and children’s MVPA. On average, children were getting 12.9 min of MVPA during recess, 17.7 min during curriculum time, and 29.0 min of MVPA outside school time. During all three time points, boys were more active than girls. During curriculum time, children in lower grades were more active, and the weather had differing impacts depending on the time of day. The findings of this study illustrate the differences in MVPA and the factors that influence MVPA by time of day. Examining different time segments provides valuable information for understanding children’s MVPA patterns

    α-C-H Photoalkylation of a Glucose Derivative in Continuous Flow

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    Site-selective photoalkylation is a powerful strategy to extend the carbon framework of carbohydrates, otherwise often attainable only through laborious syntheses. This work describes the adaptation and upscaling of the photoalkylation of a glucose derivative as a continuous flow process. The reported iridium catalyst is replaced by an organic sensitizer and the reaction has been carried out on 40-gram scale

    A railway timetable rescheduling approach for handling large scale disruptions

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    On a daily basis, relatively large disruptions require infrastructure managers and railway operators to reschedule their railway timetables together with their rolling stock and crew schedules. This research focuses on timetable rescheduling for passenger trains at a macroscopic level in a railway network. An integer programming model is formulated for solving the timetable rescheduling problem, which minimizes the number of cancelled and delayed trains while adhering to infrastructure and rolling stock capacity constraints. The possibility of rerouting trains in order to reduce the number of cancelled and delayed trains is also considered. In addition, all stages of the disruption management process (from the start of the disruption to the time the normal situation is restored) are taken into account. Computational tests of the described model on a heavily used part of the Dutch railway network show that we are able to find optimal solutions in short computation times. This makes the approach applicable for use in practice

    An exactly solvable self-convolutive recurrence

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    We consider a self-convolutive recurrence whose solution is the sequence of coefficients in the asymptotic expansion of the logarithmic derivative of the confluent hypergeometic function U(a,b,z)U(a,b,z). By application of the Hilbert transform we convert this expression into an explicit, non-recursive solution in which the nnth coefficient is expressed as the (n−1)(n-1)th moment of a measure, and also as the trace of the (n−1)(n-1)th iterate of a linear operator. Applications of these sequences, and hence of the explicit solution provided, are found in quantum field theory as the number of Feynman diagrams of a certain type and order, in Brownian motion theory, and in combinatorics

    Temperature-induced pair correlations in clusters and nuclei

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    The pair correlations in mesoscopic systems such as nmnm-size superconducting clusters and nuclei are studied at finite temperature for the canonical ensemble of fermions in model spaces with a fixed particle number: i) a degenerate spherical shell (strong coupling limit), ii) an equidistantly spaced deformed shell (weak coupling limit). It is shown that after the destruction of the pair correlations at T=0 by a strong magnetic field or rapid rotation, heating can bring them back. This phenomenon is a consequence of the fixed number of fermions in the canonical ensemble

    Thermal shape fluctuation effects in the description of hot nuclei

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    The behavior of several nuclear properties with temperature is analyzed within the framework of the Finite Temperature Hartree-Fock-Bogoliubov (FTHFB) theory with the Gogny force and large configuration spaces. Thermal shape fluctuations in the quadrupole degree of freedom, around the mean field solution, are taken into account with the Landau prescription. As representative examples the nuclei 164^{164}Er, 152^{152}Dy and 192^{192}Hg are studied. Numerical results for the superfluid to normal and deformed to spherical shape transitions are presented. We found a substantial effect of the fluctuations on the average value of several observables. In particular, we get a decrease in the critical temperature (TcT_c) for the shape transition as compared with the plain FTHFB prediction as well as a washing out of the shape transition signatures. The new values of TcT_c are closer to the ones found in Strutinsky calculations and with the Pairing Plus Quadrupole model Hamiltonian.Comment: 17 pages, 8 Figure
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