1,928 research outputs found
The Chieftal System in Twentieth Century America: Legal Aspects of the Matai System in the Territory of American Samoa
Executable Architectures and their Application to a Geographically Distributed Air Operations Center
Integrated Architectures and Network Centric Warfare represent two central concepts in the Department of Defense\u27s (DoD) on-going transformation. The true power of integrated architectures is brought to bear when they are combined with simulation to move beyond a static representation and create an executable architecture. This architecture can then be used to experiment with system configurations and parameter values to guide employment decisions. The process of developing and utilizing an executable architecture will be employed to assess an Air Operations Center (AOC). This thesis applies and expands upon the methodology of Dr. Alexander Levis, former Chief Scientist of the Air Force, to the static architecture representing the Aerospace Operations Center (AOC). Using Colored Petri Nets and other simulation tools, an executable architecture for the AOC\u27s Air Tasking Order (ATO) production thread was developed. These models were then used to compare the performance of a current, forward-deployed AOC configuration to three other potential configurations that utilize a network centric environment to deploy a portion of the AOC and provide reach-back capabilities to the non-deployed units. Performance was measured by the amount of time required to execute the ATO cycle under each configuration. Communication requirements were analyzed for each configuration and stochastic delays were modeled for all transactions in which requirements could not be met due to the physical configuration of the AOC elements. All four configurations were found to exhibit statistically different behavior with regard to ATO cycle time
Football’s InfluencE on Lifelong health and Dementia risk (FIELD): protocol for a retrospective cohort study of former professional footballers
Introduction: In the past decade, evidence has emerged suggesting a potential link between contact sport participation and increased risk of late neurodegenerative disease, in particular chronic traumatic encephalopathy. While there remains a lack of clear evidence to test the hypothesis that contact sport participation is linked to an increased incidence of dementia, there is growing public concern regarding the risk. There is, therefore, a pressing need for research to gain greater understanding of the potential risks involved in contact sports participation, and to contextualise these within holistic health benefits of sport.
Methods and analysis: Football’s InfluencE on Lifelong health and Dementia risk is designed as a retrospective cohort study, with the aim to analyse data from former professional footballers (FPF) in order to assess the incidence of neurodegenerative disease in this population. Comprehensive electronic medical and death records will be analysed and compared with those of a demographically matched population control cohort. As well as neurodegenerative disease incidence, all-cause, and disease-specific mortality, will be analysed in order to assess lifelong health. Cox proportional hazards models will be run to compare the data collected from FPFs to matched population controls.
Ethics and dissemination: Approvals for study have been obtained from the University of Glasgow College of Medical, Veterinary and Life Sciences Research Ethics Committee (Project Number 200160147) and from National Health Service Scotland’s Public Benefits and Privacy Panel (Application 1718-0120)
Neurodegenerative disease mortality among former professional soccer players
Background:
Neurodegenerative disorders have been reported in elite athletes who participated in contact sports. The incidence of neurodegenerative disease among former professional soccer players has not been well characterized.
Methods:
We conducted a retrospective cohort study to compare mortality from neurodegenerative disease among 7676 former professional soccer players (identified from databases of Scottish players) with that among 23,028 controls from the general population who were matched to the players on the basis of sex, age, and degree of social deprivation. Causes of death were determined from death certificates. Data on medications dispensed for the treatment of dementia in the two cohorts were also compared. Prescription information was obtained from the national Prescribing Information System.
Results:
Over a median of 18 years, 1180 former soccer players (15.4%) and 3807 controls (16.5%) died. All-cause mortality was lower among former players than among controls up to the age of 70 years and was higher thereafter. Mortality from ischemic heart disease was lower among former players than among controls (hazard ratio, 0.80; 95% confidence interval [CI], 0.66 to 0.97; P=0.02), as was mortality from lung cancer (hazard ratio, 0.53; 95% CI, 0.40 to 0.70; P<0.001). Mortality with neurodegenerative disease listed as the primary cause was 1.7% among former soccer players and 0.5% among controls (subhazard ratio [the hazard ratio adjusted for competing risks of death from ischemic heart disease and death from any cancer], 3.45; 95% CI, 2.11 to 5.62; P<0.001). Among former players, mortality with neurodegenerative disease listed as the primary or a contributory cause on the death certificate varied according to disease subtype and was highest among those with Alzheimer’s disease (hazard ratio [former players vs. controls], 5.07; 95% CI, 2.92 to 8.82; P<0.001) and lowest among those with Parkinson’s disease (hazard ratio, 2.15; 95% CI, 1.17 to 3.96; P=0.01). Dementia-related medications were prescribed more frequently to former players than to controls (odds ratio, 4.90; 95% CI, 3.81 to 6.31; P<0.001). Mortality with neurodegenerative disease listed as the primary or a contributory cause did not differ significantly between goalkeepers and outfield players (hazard ratio, 0.73; 95% CI, 0.43 to 1.24; P=0.24), but dementia-related medications were prescribed less frequently to goalkeepers (odds ratio, 0.41; 95% CI, 0.19 to 0.89; P=0.02).
Conclusions:
In this retrospective epidemiologic analysis, mortality from neurodegenerative disease was higher and mortality from other common diseases lower among former Scottish professional soccer players than among matched controls. Dementia-related medications were prescribed more frequently to former players than to controls. These observations need to be confirmed in prospective matched-cohort studies. (Funded by the Football Association and Professional Footballers’ Association.
Bulletin No. 203 - Cattle Ranching in Utah: Report of a Preliminary Economic Survey of the Ranch Situations as of 1925
The Mexican War ended in 1846, but the treaty of Guadalupe Hidalgo was not signed until 1848. Meantime, Utah was occupied by the Mormon pioneers, who having no land laws to guide them took land according to a plan furnished by Brigham Young. In Salt Lake City 10-acre blocks were divided into 8 building lots of 1 1/4 acres each. Just at the edge of the city were five acre lots to accommodate mechanics and artisans; next beyond were 10-acre lots, followed by forty and eighty acres, where farmers could build and reside
Identification of source-sink dynamics in mountain lions of the Great Basin
Natural and anthropogenic boundaries have been shown to affect population dynamics and population structure for many species with movement patterns at the landscape level. Understanding population boundaries and movement rates in the field for species that are cryptic and occur at low densities is often extremely difficult and logistically prohibitive; however genetic techniques may offer insights that have previously been unattainable. We analyzed thirteen microsatellite loci for 739 mountain lions (Puma concolor) using muscle tissue samples from individuals in the Great Basin throughout Nevada and the Sierra Nevada mountain range to test the hypothesis that heterogeneous hunting pressure results in source-sink dynamics at the landscape scale. We used a combination of non-spatial and spatial model-based Bayesian clustering methods to identify genetic populations. We then used a recently developed Bayesian multilocus genotyping method to estimate asymmetrical rates of contemporary movement between those subpopulations and to identify source and sink populations. We identified two populations at the highest level of genetic structuring with a total of five subpopulations in the Great Basin of Nevada and the Sierra Nevada range. Our results suggest that source-sink dynamics occur at landscape scales for wide-ranging species, such as mountain lions, and that source populations may be those that are under relatively less hunting pressure and that occupy refugia
Nondestructive Electromagnetic Material Characterization using a Dual Waveguide Probe: A Full Wave Solution
A nondestructive technique for determining the complex permittivity and permeability of a perfect electric conductor backed magnetic shielding material using a dual waveguide probe is presented. The dual waveguide probe allows for the simultaneous collection of reflection and transmission coefficients which distinguishes it from single probe methods common in the literature. Theoretical development of these coefficients, which is accomplished through a coupled magnetic field integral equations formulation using Love\u27s equivalence principle and solved via the method of moments (MOM), is discussed. Evaluation of the resulting MOM impedance matrix elements is performed using complex plane integration leading to enhanced computational efficiency and physical insight. Comparison of the theoretical and measured reflection and transmission coefficients using a root finding algorithm leads to the desired permittivity and permeability. Measurement results of a magnetic shielding material are presented and compared to traditional methods for the purpose of validating the new technique. The probe\u27s sensitivity to aperture alignment, sample thickness, and flange thickness is also investigated.Abstract © AGU
Towards smallholder food and water security: Climate variability in the context of multiple livelihood hazards in Nicaragua
Climate variability and change affect both food and water security, as do other hazards, such as shifting food prices, plant pathogens, and political economic changes. Although household food and water insecurity affect billions, most studies analyze them separately. This article develops a relational approach to explaining household access to food and water in a multi-hazard context. We identify pathways linking hazards to livelihood vulnerability and assess the relative importance of climate-related hazards. Analyzing longitudinal data collected from two surveys of the same 311 smallholder households in northern Nicaragua, conducted in 2014 and again in 2017, we find that peak seasons of food and water stress are asynchronous across the agricultural calendar, resulting in a total of five to six months of food and/or water stress. Across households, we find a significant positive relationship between water and food insecurity, even after adjusting for household fixed effects. Households experienced less food and water insecurity in 2017 than in 2014, due in part to the end of a severe drought in 2016, but remained concerned about damage from a severe coffee leaf rust outbreak and unfavorable agrifood prices that reduce income and threaten food security. Higher incomes and larger farm areas correlated with improved food and water security. We propose a generalizable approach for the joint assessment of household food and water security, which foregrounds the influence of seasonality and climate variability in the context of multiple hazards. This approach and our findings can contribute to developing integrated risk reduction strategies, building resilient livelihoods, and informing policy changes and partnerships with organized smallholders to improve resource access and sovereignty
Left ventricular function after valve repair for chronic mitral regurgitation: Predictive value of preoperative assessment of contractile reserve by exercise echocardiography
Objectives.We evaluated the value of preoperative assessment of left ventricular contractile reserve in predicting ventricular function after valve repair for minimally symptomatic mitral regurgitation.Background.The optimal timing for operation in minimally symptomatic patients with significant mitral regurgitation is controversial. Accurate preoperative assessment of left ventricular function is difficult, and the ability to predict postoperative function is limited. Previous studies in patients undergoing mitral valve replacement may not be applicable in the present era of valve repair.Methods.We performed exercise echocardiography in 139 patients with isolated mitral regurgitation and no coronary disease, 74 of whom subsequently underwent uncomplicated valve repair. We measured rest left ventricular end-systolic dimension, end-systolic wall stress and positive first derivative of left ventricular pressure (dP/dt). End-diastolic and end-systolic volumes and ejection fraction were measured preoperatively at rest, immediately after exercise and postoperatively.Results.Ejection fraction decreased postoperatively to 55 ± 10% from a rest preoperative value of 64 ± 9% (p < 0.001). Compared with patients with a postoperative ejection fraction ≥50% (n = 56), patients with postoperative ejection fraction <50% (n = 18) had a significantly lower preoperative exercise ejection fraction (57 ± 11% vs. 73 ± 9%, p < 0.0005), a larger exercise end-systolic volume index (32 ± 8 vs. 18 ± 7 cm3/m2, p < 0.0005) and a lower change in ejection fraction with exercise (−4 ± 8% vs. 9 ± 10%, p < 0.005). Preoperative rest indexes, including dP/dt, end-systolic wall stress and end-systolic volume index were less predictive, whereas exercise capacity, rest ejection fraction and end-systolic dimension were not predictive of postrepair ejection fraction. An exercise end-systolic volume index >25 cm3/m2 was the best predictor of postoperative dysfunction, with a sensitivity and specificity of 83%.Conclusions.In minimally symptomatic patients with mitral regurgitation, latent ventricular dysfunction may be indicated by a limited contractile reserve, manifest at exercise as an inadequate increase in ejection fraction and a larger end-systolic volume. These variables may also be used to predict left ventricular function after repair
Vaccination With Mouse Dendritic Cells Loaded With an IpaD-IpaB Fusion Provides Protection Against Shigellosis
This work is licensed under a Creative Commons Attribution 4.0 International License.Diarrheal diseases are a major cause of morbidity and mortality worldwide. They are most prevalent in settings with inadequate sanitation, poor hygiene and contaminated water. An important diarrheal pathogen in such settings is Shigella. No commercially available vaccine exists against shigellosis and immunity to the pathogen is serotype-restricted. We have previously shown that a polypeptide fusion of the Type Three Secretion Apparatus (T3SA) proteins IpaB and IpaD (named DBF) was efficacious as a vaccine against Shigella. Vaccination using different administration routes indicated that protection conferred by DBF did not fully correlate with antibodies. To define the immune responses involved in protection, we studied cellular responses to intranasal immunization with the DBF and the adjuvant dmLT. We found dendritic cell (DC) activation at the nasal associated lymphoid tissue (NALT). Activation markers CD86 and MHCII significantly increase in cells from immunized mice. Antigen exposure in vitro further confirmed the upregulation of CD80 and CD40 in primary dendritic cells. Animals immunized with antigen-primed dendritic cells were protected against Shigella infection, at levels comparable to the efficacy of immunization with the protein vaccine formulation. Therefore, we show that antigen-primed DCs are enough to provide immunity, and propose a mechanism of protection against Shigella spp. based on DC-mediated antigen presentation to T cells.NIH R01 AI 007337
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