Alleviating chronic sleep debt in early adolescence Can a school based intervention make a difference?

In the past decade, researchers have gained a better understanding of adolescent sleep needs, and have developed a growing concern for the chronically insufficient quantity and quality of sleep experienced by up to 80% of today s youth (National Sleep Foundation, 2006). While tolerance for inadequate sleep varies among individuals, a growing body of scientific evidence demonstrates that inadequate sleep results in varying degrees of increased daytime sleepiness, and may negatively impact health, behavior, emotions, and academic achievement. The underlying causes of insufficient quantity and quality of sleep may be related to behavioral, environmental, and /or physiological factors. The purpose of this study was to investigate an educational program designed to increase nightly sleep time towards a target goal of the recommended 9 hours per night. The educational program, Sleep For Your Health, aimed to increase awareness of the importance of adequate sleep in 12-14 year old adolescents through implementation of a school-based curriculum. Two theories, Bruner s (1966) Discovery Learning model and Bronfenbrenner s (2005) bio-ecological theory, provided the framework for curriculum development. The pretest-posttest study with an intervention group and a control group included two classes of combined 7th and 8th grade students (n=48) attending an urban public middle school. Total sleep time (TST) was measured using wrist actigraphy. Daytime sleepiness (DS) was measured using the Cleveland Adolescent Sleepiness Questionnaire (CASQ). Following the educational program, conducted weekly for six consecutive weeks, TST and DS were reassessed. No significant relationship existed between TST and DS, or sleep quality and DS. No significant changes in mean TST or DS scores occurred in the intervention group compared to the control group. Student and parent scores on a post-intervention quiz demonstrated a strong understanding of the concepts presented in the Sleep for Your Health curriculum. On the post-intervention survey, the majority of students indicated they were trying to get more nightly sleep, with 55% demonstrating an increase in sleep time by an average of 65 minutes a night. Based on post-intervention feedback from participants, the approach was acceptable, with only minor suggestions offered for improvement in the curriculum

The Relationship between Moderate, Within Day Protein Intake and Energy Balance on Body Composition of Collegiate Sand Volleyball Players

Title: The Relationship between Moderate, Within Day Protein Intake and Energy Balance on Body Composition of Collegiate Sand Volleyball Players Background: Achieving an ideal body composition with relatively low fat mass and relatively high fat-free mass (FFM) is desirable for virtually all competitive athletes. Some studies suggest that protein intake, depending on quality, amount, and timing, may improve relative musculature by stimulating muscle protein synthesis, but some issues related to timing and amount of protein intake remain unclear. Current evidence suggests that frequent consumption of moderate amounts of protein is useful for muscle building. Purpose: The purpose of this study was to simultaneously assess energy balance and protein intake to determine if these factors are associated with body composition in a population of collegiate sand volleyball players. Methods: In a cross sectional, observational study, players completed a food intake and activity form for a 24-hour period to serve as the basis of energy balance and protein intake assessment. The assessment day was representative of a typical day during the regular training season. These data were entered into a software program providing total and hourly energy balance and nutrient content of the consumed foods. Athletes were measured for body composition via a multi-current bioelectrical impedance scale to predict weight, BMI, fat mass and fat free mass. Height was measured using a standard wall-mounted stadiometer. Data analyses included descriptive and frequency statistics, Spearman correlations and regression analyses. Results: Twelve women from the GSU sand volleyball team participated in the study using an IRB-approved protocol. The mean BMI was 22 kg/m2 (±3 kg/m2) and the mean body fat percentage was 18% (±7%). The mean protein intake for all participants was 132 grams (±52 g). Protein intake distribution was skewed, on average, toward the latter half of the day with approximately 19% of protein consumed in the morning and 34% consumed in the evening. The mean net energy balance at the end of the 24-hour assessment period was -404 (±385) kcal. Athletes, on average, spent 17 hours in a catabolic energy balance state (\u3c 0 kcal). No significant correlation was found between energy balance per gram of protein consumption and body composition. However, regression analyses indicated that energy balance and protein variables explain a significant proportion (p=.037) of the variance in body fat percentage. Conclusions: Sand volleyball players in this study spent a high proportion of time in a negative energy balance, which may have compromised the potential benefit that frequent protein consumption may have had on FFM. Since both energy balance and protein explain a significant proportion of the variance in body composition, these athletes might benefit from improving within-day energy balance as a strategy for optimizing body composition

Ill-posedness of the mean-field model of superconducting vortices and a possible regularisation

We conjecture that the mean-field model of superconducting vortices given in [10] is ill-posed wherever the electric current j has some component in the same direction as the vorticity vector ? (which gives the average density and direction of the superconducting vortices). The conjecture is illustrated with a linear stability analysis of a certain solution to the model. A regularised model is then proposed, and this is used to demonstrate the instability of force-free steady states in a certain geometry

The future of transportation in society: Forces of change

The transportation system is a critical element of the social / political / economic system of the United States. Factors influencing the use of transportation technology include technology push, market pull, and external factors. In order for new transportation technology to be successful, it must meet the needs of the market. These needs are diverse and vary almost by individual. Historical trends show great changes in transportation use by mode and origins and destinations of trips. Other important changes in society affecting transportation use include changes in the composition of society by gender, age, national origin, family composition, land use, income, and residential distribution. Changes of these factors in the future and how technology is deployed to meet the changing needs of society will affect the success of transportation technology implementation over the next twenty years

Effects of Nutrient Availability and Other Elevational Changes on Bromeliad Populations and Their Invertebrate Communities in a Humid Tropical Forest in Puerto Rico

Nutrient inputs into tank bromeliads were studied in relation to growth and productivity, and the abundance, diversity and biomass of their animal inhabitants, in three forest types along an elevational gradient. Concentrations of phosphorus, potassium and calcium in canopy-derived debris, and nitrogen and phosphorus in phytotelm water, declined with increasing elevation. Dwarf forest bromeliads contained the smallest amounts of debris/plant and lowest concentrations of nutrients in plant tissue. Their leaf turnover rate and productivity were highest and, because of high plant density, they comprised 12.8and contained 3.3 t ha -1 of water. Annual nutrient budgets indicated that these microcosms were nutrient-abundant and accumulated \u3c 5dwarf forest, where accumulation was c. 25biomass/plant peaked in the intermediate elevation forest, and were positively correlated with the debris content/bromeliad across all forest types. Animal species richness showed a significant mid-elevational peak, whereas abundance was independent of species richness and debris quantities, and declined with elevation as forest net primary productivity declined. The unimodal pattern of species richness was not correlated with nutrient concentrations, and relationships among faunal abundance, species richness, nutrient inputs and environment are too complex to warrant simple generalizations about nutrient resources and diversity, even in apparently simple microhabitats

An analysis of the Jack Faucett Associates Automobile Sector Forecasting Model

Motor Vehicle Manufacturers Association, Detroit, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/352/2/47022.0001.001.pd

An inventory of selected mathematical models relating to the motor vehicle transportation system and associated literature

Motor Vehicle Manufacturers Association, Detroit, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/547/2/41051a02.0001.001.pd

A review of the revisions to the Wharton EFA Automobile Demand Model: Mark I and II - an interim report

Motor Vehicle Manufacturers Association, Detroit, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/458/2/44613.0001.001.pd

Toward estimating intelligent transportation system benefits based on user needs

Transportation Department, Washington, D.C.University of Michigan, Ann Arbor, Intelligent Transportation System Research Center of Excellencehttp://deepblue.lib.umich.edu/bitstream/2027.42/1310/2/94307.0001.001.pd