2,658 research outputs found
Effect of 3-aminobenzamide on chromosome damage in human blood lymphocytes adapted to bleomycin
Human blood lymphocytes, pre-treated with very low (adaptation) concentrations of bleomycin for 48 h and then exposed to a high (challenge) dose of the same agent or X-rays, became significantly less sensitive to the induction of chromosome damage than those which did not receive the pre-treatment, indicating an induction of āadaptive repair' process. This repair process was negated when 3-amino-benzainide, an inhibitor of poly (ADP) polymerase, was added to the cultures immediately after the challenge treatment. The magnitude of negation in the adaptation response was greater in the case of lymphocytes challenged with X-rays as compared with those challenged with bleomyci
Feasibility, Acceptability, and Preliminary Efficacy of a Recess-Based Fitness Intervention in Elementary School Children
International Journal of Exercise Science 12(4): 1225-1243, 2019. Although fitness may benefit cognition in youth, most attention has been given to cardiorespiratory fitness despite the health benefits of muscular fitness. Few studies have examined interventions that incorporate both cardiorespiratory and muscular fitness or have been offered during school recess. Furthermore, most fitness intervention studies examining cognitive outcomes have not reported on implementation information. The purpose of this pilot study was to examine the feasibility, acceptability, and preliminary efficacy on fitness and cognition of a recess intervention in elementary school children. Two schools were randomized to either a 3-month cardiorespiratory and muscular fitness intervention (15 minutes/weekday during recess) or control condition (standard recess activities). Process evaluation (feasibility and acceptability) measures were recorded daily (research staff questionnaire), weekly (accelerometer and heart rate monitors), and post-intervention (participant and school-staff questionnaires). Preliminary efficacy measures included pre- and post-intervention inhibition/attention, working memory, and cardiorespiratory and muscular fitness scores. Some feasibility and acceptability measures were favorable (88% of the lessons were implemented, 78% of the lessons were implemented as planned, and the majority of students and school staff were satisfied with most aspects of the intervention). However, intensity adherence during the intervention sessions based on accelerometry (% of time spent in moderate-to-vigorous activity: 41.7 Ā± 14.5) and participation (19.4% attendance rate) were lower than expected. Preliminary efficacy of the intervention on cognitive and fitness outcomes was not demonstrated. This study provided evidence that some aspects of the fitness intervention were acceptable during school recess. However, important implementation factors (i.e., intervention exposure) should be targeted to improve youth fitness programs offered during this school setting
Process evaluation of a culturally-tailored physical activity intervention in African-American mother-daughter dyads
The purpose of this study was to describe process evaluation data including intervention fidelity, dosage, quality, participant responsiveness, and program reach for the Mothers And dauGhters daNcing togEther Trial (MAGNET) in Springfield, MA, in Spring 2013 and 2014. Seventy-six mother-daughter dyads were randomized to the mother-daughter group (CH-M, n = 28), the child-only group (CH, n = 25), or the health education group (CON, n = 23). CH-M consisted of 60 min of moderate-to-vigorous culturally-tailored dance classes for dyads. CH consisted of dance classes for the child. All groups received homework tutoring and weekly health newsletters. Process evaluation data were assessed at each intervention session (three days/week, 6-months) with semi-structured questionnaires by researchers. CH dance classes were slightly longer (58.2 Ā± 3.5 min) than CH-M (54.4 Ā± 5.5 min). In both groups, participants spent the majority of the dance intervention in light intensity physical activity (PA). Participants in the CH-M group enjoyed participating in MAGNET \u3e 90% of the time. Mothers (92%) indicated that they wanted to continue dance as a form of PA. Mothers expressed that transportation, time commitment, and assessments were barriers to participation. Participants suggested future interventions should include longer intervention length and more communications between research staff and mothers. The MAGNET intervention matched the originally intended program in most aspects. A lower intervention dose was delivered to the CH-M group potentially due to barriers described by mothers. Because mother-daughter interventions have shown minimal effects on increasing PA, it is imperative that researchers utilize process evaluation data to shape future studies
Estimating Atrazine Leaching in the Midwest
Data from seven Management Systems Evaluation Areas (MSEM) were used to test the sensitivity of a leaching model, PRZM-2, to a variety of hydrologic settings common in the Midwest. Atrazine leaching was simulated because the use of atrazine was prevalent in the MSEA studies and it frequently occurs in the region\u27s groundwater. Results of long-term simulations using regional and generalized input parameters produced ranks of leaching potential similar to those based on measurements. Short-term simulations used site-specific soil and chemical coefficients
Measurements of the effect of collisions on transverse beam halo diffusion in the Tevatron and in the LHC
Beam-beam forces and collision optics can strongly affect beam lifetime,
dynamic aperture, and halo formation in particle colliders. Extensive
analytical and numerical simulations are carried out in the design and
operational stage of a machine to quantify these effects, but experimental data
is scarce. The technique of small-step collimator scans was applied to the
Fermilab Tevatron collider and to the CERN Large Hadron Collider to study the
effect of collisions on transverse beam halo dynamics. We describe the
technique and present a summary of the first results on the dependence of the
halo diffusion coefficient on betatron amplitude in the Tevatron and in the
LHC.Comment: 4 pages, 2 figures. Submitted to the Proceedings of the ICFA
Mini-Workshop on Beam-beam Effects in Hadron Colliders (BB2013), Geneva,
Switzerland, 18-22 March 201
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Cross-Sectional Associations of 24-Hour Sedentary Time, Physical Activity, and Sleep Duration Compositions with Sleep Quality and Habits in Preschoolers
Although some studies indicate physical activity and sleep quality are positively associated in children, most reports examined physical activity independent of other 24-h behaviors and focused on older children. The aim of this cross-sectional study was to examine the predicted changes in sleep efficiency and habits when reallocating time between movement behaviors using compositional isotemporal substitution in preschool-aged children. Accelerometers were worn by 288 participants (51.6 Ā± 9.5 months) for up to 16 days. Sleep outcomes included sleep efficiency, nap frequency, sleep disturbances, and bedtime resistance. Compositional isotemporal substitution analyses demonstrated that the combined effect of 24-h movement behaviors was associated with sleep efficiency (p \u3c 0.001) and nap frequency (p \u3c 0.003). When sleep increased by 30 min at the expense of stationary time or light physical activity, estimates of sleep efficiency and bedtime resistance decreased while nap frequency increased. When stationary time increased by 30 min from moderate to vigorous physical activity, estimated sleep efficiency increased and sleep disturbances decreased. Although this study presents preliminary evidence that 24-h movement behavior compositions in early childhood are associated with sleep quality and nap frequency, estimated effects from theoretical time reallocations across sleep outcomes were mixed
Towards a Notion of Distributed Time for Petri Nets
We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models
Properties, use and health effects of depleted uranium (DU): a general overview.
Abstract Depleted uranium (DU), a waste product of uranium enrichment, has several civilian and military applications. It was used as armor-piercing ammunition in international military conflicts and was claimed to contribute to health problems, known as the Gulf War Syndrome and recently as the Balkan Syndrome. This led to renewed efforts to assess the environmental consequences and the health impact of the use of DU. The radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher. Due to the low specific radioactivity and the dominance of alpharadiation no acute risk is attributed to external exposure to DU. The major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU. Since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons. Urine, feces, hair and nails record recent exposures to DU. With the exception of crews of military vehicles having been hit by DU penetrators, no body burdens above the range of values for natural uranium have been found. Therefore, observable health effects are not expected and residual cancer risk estimates have to be based on theoretical considerations. They appear to be very minor for all post-conflict situations, i.e. a fraction of those expected from natural radiation
Nonadjacent dependency processing in monkeys, apes and humans
The ability to track syntactic relationships between words, particularly over distances (ānonadjacent dependenciesā), is a critical faculty underpinning human language, although its evolutionary origins remain poorly understood. While some monkey species are reported to process auditory nonadjacent dependencies, comparative data from apes are missing, complicating inferences regarding shared ancestry. Here, we examined nonadjacent dependency processing in common marmosets, chimpanzees, and humans using āartificial grammarsā: strings of arbitrary acoustic stimuli composed of adjacent (nonhumans) or nonadjacent (all species) dependencies. Individuals from each species (i) generalized the grammars to novel stimuli and (ii) detected grammatical violations, indicating that they processed the dependencies between constituent elements. Furthermore, there was no difference between marmosets and chimpanzees in their sensitivity to nonadjacent dependencies. These notable similarities between monkeys, apes, and humans indicate that nonadjacent dependency processing, a crucial cognitive facilitator of language, is an ancestral trait that evolved at least ~40 million years before language itself
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