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Search Results: 1 - 10 of 477866 matches for " James A. Larson "
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Youth Physical Activity and Enjoyment during Semi-Structured versus Unstructured School Recess  [PDF]
Jessyka N. Larson, Timothy A. Brusseau, Benjamin Chase, Angela Heinemann, James C. Hannon
Open Journal of Preventive Medicine (OJPM) , 2014, DOI: 10.4236/ojpm.2014.48072

Background: Physical activity throughout the school day may help reduce the risk of childhood obesity. Semi-structured recess is a unique approach to create more physical activity. Therefore, the purpose of this study was to compare the physical activity and enjoyment of urban school children during traditional unstructured recess and semi-structured recess. Method: Children from the Southwestern US (N = 165) wore a NL-1000 piezoelectric accelerometer during their 15-minute lunch recess. Children participated in both their traditional unstructured (no structure and no equipment) recess and semi-structured (organized games and equipment) recess. An enjoyment scale was completed after both types of recess formats. Results: During unstructured recess, children accumulated 1028 ± 356 steps and 4.59 ± 2.2 minutes of MVPA compared to 1156 ± 434 steps and 5.44 ± 2.76 minutes of moderate to vigorous physical activity (MVPA) during semi-structured recess. Paired sample t-tests revealed that children took significantly more steps (t = 4.98; p < 0.001) and MVPA (t = 5.940; p < 0.001) during semi-structured recess. No significant differences were found for enjoyment (p = 0.847) between recesses. Conclusions: It is important for schools to consider creative, semi-structured recess opportunities to increase step counts and time in MVPA (while maintaining

Fit “n” Cool Kids: Effects of Peer-Modeling and Goal Setting on Physical Activity  [PDF]
Jessyka N. Larson, Timothy A. Brusseau, Maria M. Newton, Stuart J. Fairclough, Heidi Wengreen, James C. Hannon
Open Journal of Preventive Medicine (OJPM) , 2018, DOI: 10.4236/ojpm.2018.84008
Abstract: Background: Decreasing the risk of overweight and obesity from an early age is imperative and efforts should focus on fostering children’s physical activity (PA). Within school-based interventions, there is insufficient evidence on the effectiveness of the use of character peer-modeling and goal setting to increase physical activity. Therefore, the purpose of this study was to examine the impact of a school-based intervention on PA and enjoyment of PA in grades 3 - 5 elementary school age children at two urban elementary schools. Methods: Participants were 95 students of 8 - 10 years old; activity monitors were used to assess physical activity. Daily physical activity and enjoyment was recorded at baseline, intervention, and at a 6-school-week follow-up. Results: PA significantly increased in the intervention school averaging 5549 steps at baseline, 5889 steps during the intervention, and 6515 during follow-up (p < 0.05). Participants significantly increased their moderate to vigorous physical activity from 28.54 min at baseline to 30.06 minutes at week 4 and 36.45 during follow-up (p < 0.05). There was no change in enjoyment levels from baseline to follow-up. Conclusion: The Fit “n” Cool Kids intervention presents the potential of peer-modeling and goal setting for increasing PA at school. Continued interventions in schools may positively influence children’s healthy living patterns.
Disease prevention without relapse: Processes of change for HPV vaccination  [PDF]
Anne C. Fernandez, Andrea L. Paiva, Jessica M. Lipschitz, H. Elsa Larson, Nicole R. Amoyal, Cerissa L. Blaney, Marie A. Sillice, Colleen A. Redding, James O. Prochaska
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.33041

Background: Human papillomavirus is the most prevalent sexually transmitted infection in the United States and is associated with 70% of cervical cancers as well as over 90% of genital warts. Although the HPV vaccine appears in the US immunization schedule during adolescence, a large percentage of women reach adulthood without being vaccinated. The Transtheoretical Model’s (TTM) Processes of Change (POC) construct provides an assessment of participants’ experiences with HPV vaccination and is a central component of computer-tailored interventions designed to increase compliance with medical recommendations, such as vaccination. This study describes development and validation of a POC measure for increasing HPV vaccination among young adult women. Methods: Cross-sectional measurement development was conducted using an online survey to reach a sample of 340 female college students representing vaccinated and unvaccinated women. Factor analytic structural equation modeling as well as evaluations of the stage by POC were used to evaluate the validity of the POC measure. Results: Confirmatory analyses supported the theoretically expected ten-factor, fully correlated model as the best fit for the data. Expected Stage of Change to POC relationships were also confirmed insofar as each POC was significantly associated with Stage of Change, with the exception of dramatic relief. Follow-up analyses suggested that individuals in the Precontemplation stage used all POC less frequently than individuals in all other stages. Conclusions: The POC measure was found to be internally and externally valid in a sample of college-attending women. The POC measure developed may be used to tailor stage-matched interventions that increase use of experiential and behavioral strategies important for increasing HPV vaccination in this high-risk population.

Ecological Importance of Large-Diameter Trees in a Temperate Mixed-Conifer Forest
James A. Lutz, Andrew J. Larson, Mark E. Swanson, James A. Freund
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036131
Abstract: Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m2. We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances <10 m. Competition alone was insufficient to explain the spatial patterns of large-diameter trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees.
The Importance of Large-Diameter Trees to Forest Structural Heterogeneity
James A. Lutz, Andrew J. Larson, James A. Freund, Mark E. Swanson, Kenneth J. Bible
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082784
Abstract: Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥1 cm dbh, all 1,966 snags ≥10 cm dbh, and all shrub patches ≥2 m2. Basal area of the 26 woody species was 62.18 m2/ha, of which 61.60 m2/ha was trees and 0.58 m2/ha was tall shrubs. Large-diameter trees (≥100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P≤0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.
Intraocular pressure and aqueous humor flow during a euglycemic-hyperinsulinemic clamp in patients with type 1 diabetes and microvascular complications
James T Lane, LuAnn Larson, Shan Fan, Julie A Stoner, Eyal Margalit, Carol B Toris
BMC Ophthalmology , 2010, DOI: 10.1186/1471-2415-10-19
Abstract: Ten patients with type 1 diabetes and ten healthy age- and weight-matched controls were studied. Aqueous flow was measured by fluorophotometry during a hyperinsulinemic-euglycemic clamp (insulin 2 mU/kg/min). Intraocular pressure was measured by tonometry at -10, 90 and 240 minutes from the start of the clamp, and outflow facility was measured by tonography at 240 minutes.During conditions of identical glucose and insulin concentrations, mean aqueous flow was lower by 0.58 μl/min in the diabetes group compared to controls (2.58 ± 0.65 versus 3.16 ± 0.66 μl/min, respectively, mean ± SD, p = 0.07) but statistical significance was not reached. Before the clamp, IOP was higher in the diabetes group (22.6 ± 3.0 mm Hg) than in the control group (19.3 ± 1.8 mm Hg, p = 0.01) but at 90 minutes into the clamp, and for the remainder of the study, IOP was reduced in the diabetes group to the level of the control group. Ocular pulse amplitude and outflow facility were not different between groups. Systolic blood pressure was significantly higher in the diabetes group, but diastolic and mean arterial pressures were not different.We conclude that compared to healthy participants, patients with type 1 diabetes having microalbuminuria and retinopathy have higher IOPs that are normalized by hyperinsulinemia. During the clamp, a reduction in aqueous flow was not statistically significant.Maintenance of intraocular pressure (IOP) within a narrow range is essential for the normal health of the eye. The IOP is kept within these limits by the production rate of aqueous humor into the posterior chamber of the eye and its drainage out of the anterior chamber angle. The production rate can be assessed by measuring the aqueous flow rate from the posterior chamber into the anterior chamber. In addition to contributing to the maintenance of IOP, the flow of aqueous humor delivers nourishment to and removes waste products from the avascular structures within the anterior segment [1]. Thus, adequ
Economic Impacts of Using Switchgrass as a Feedstock for Ethanol Production: A Case Study Located in East Tennessee
Burton C. English,Tun-Hsiang Edward Yu,James A. Larson,R. Jamey Menard
Economics Research International , 2013, DOI: 10.1155/2013/138485
Economic Impacts of Using Switchgrass as a Feedstock for Ethanol Production: A Case Study Located in East Tennessee
Burton C. English,Tun-Hsiang Edward Yu,James A. Larson,R. Jamey Menard,Yuan Gao
Economics Research International , 2013, DOI: 10.1155/2013/138485
Abstract: One of the major motivations to establish a biobased energy sector in the United States is to promote economic development in the rural areas of the nation. This study estimated the economic impact of investing and operating a switchgrass-based ethanol plant in East Tennessee. Applying a spatially oriented mixed-integer mathematical programming model, we first determined the location of biorefinery, feedstock draw area, and the resources used in various feedstock supply systems by minimizing the total plant gate cost of feedstock. Based on the model output, an input-output model was utilized to determine the total economic impact, including direct, indirect, and induced effects of feedstock investment and annual production in the study region. Moreover, the economic impact of ethanol plant investment and annual conversion operation was analyzed. Results suggest that the total annual expenditures in an unprotected large round bale system generated a total $92.5 million in economic output within the 13 counties of East Tennessee. In addition, an estimated $234 million in overall economic output was generated through the operation of the biorefinery. This research showed that the least-cost configuration of the feedstock supply chain influenced the levels and types of economic impact of biorefinery. 1. Introduction The Energy Independence and Security Act of 2007 mandates 136 billion liters of biofuels to be produced annually by the year 2022 with 61 billion liters coming from cellulosic sources [1]. A major source of feedstock required to meet the mandate is lignocellulosic biomass (LCB). As indicated in two recent studies, the United States is capable of producing over a billion tons of LCB annually [2, 3]. Produced from dedicated energy crops, crop and forest residues, and municipal solid waste streams, LCB can play a significant role in the production of biobased fuels, power, and products in the United States. The Roadmap for Bioenergy and Biobased Products in the United States [4] indicates that the development of a biobased industrial sector using LCB feedstock in the United States can reduce dependence on imported petroleum, add to the diversity of energy sources, enhance energy security, improve the balance of trade, reduce carbon emissions, increase carbon sequestration, and stimulate economic growth in rural areas. This research evaluates the potential economic impacts of locating a switchgrass-to-ethanol biorefinery in rural East Tennessee, USA. Switchgrass is a strong candidate as a dedicated energy crop for biofuel production because it is a
Crossing to Safety: Transforming Healthcare Organizations for Patient Safety
Ralston James,Larson E
Journal of Postgraduate Medicine , 2005,
Abstract: The current healthcare system is not designed to ensure better patient safety. In addition, healthcare is simultaneously becoming increasingly complex and increasingly fragmented. Medical knowledge and technology are expanding at an incredible rate, making it difficult for the healthcare providers to keep pace with advancing knowledge. Patients' needs are changing too: shifting from the diagnosis and treatment of a single, acute problem to the long-term management of multiple, interrelated chronic conditions. Our systems of care are not keeping up with these changes and, consequently, patients are experiencing unnecessary risk. Improving patient safety requires a transformation in how we currently care for patients. Healthcare organizations must adopt a new paradigm of care that holds patient safety as a core value and practice. To achieve this aim, healthcare organizations should build and maintain a culture of patient safety, provide leadership for patient safety that establishes a blame-free environment, proactively survey and monitor for adverse events, continually engineer patient safety into healthcare processes, and provide information and communication technologies to support patient safety.
Evidence for loss of synaptic AMPA receptors in anterior piriform cortex of aged mice
James Gocel,John Larson*
Frontiers in Aging Neuroscience , 2013, DOI: 10.3389/fnagi.2013.00039
Abstract: It has been suggested that age-related impairments in learning and memory may be due to age-related deficits in long-term potentiation of glutamatergic synaptic transmission. For example, olfactory discrimination learning is significantly affected by aging in mice and this may be due, in part, to diminished synaptic plasticity in piriform cortex. In the present study, we tested for alterations in electrophysiological properties and synaptic transmission in this simple cortical network. Whole-cell recordings were made from principal neurons in slices of anterior piriform cortex from young (3–6 months old) and old (24–28 months) C57Bl/6 mice. Miniature excitatory postsynaptic currents (mEPSCs) mediated by AMPA receptors were collected from cells in presence of tetrodotoxin (TTX) and held at -80 mV in voltage-clamp. Amplitudes of mEPSCs were significantly reduced in aged mice, suggesting that synaptic AMPA receptor expression is decreased during aging. In a second set of experiments, spontaneous excitatory postsynaptic currents (s/mEPSCs) were recorded in slices from different cohorts of young and old mice, in the absence of TTX. These currents resembled mEPSCs and were similarly reduced in amplitude in old mice. The results represent the first electrophysiological evidence for age-related declines in glutamatergic synaptic function in the mammalian olfactory system.
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