853 resultados para Nathan
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The High-Altitude Water Cherenkov (HAWC) Experiment is a gamma-ray observatory that utilizes water silos as Cherenkov detectors to measure the electromagnetic air showers created by gamma rays. The experiment consists of an array of closely packed water Cherenkov detectors (WCDs), each with four photomultiplier tubes (PMTs). The direction of the gamma ray will be reconstructed using the times when the electromagnetic shower front triggers PMTs in each WCD. To achieve an angular resolution as low as 0.1 degrees, a laser calibration system will be used to measure relative PMT response times. The system will direct 300ps laser pulses into two fiber-optic networks. Each network will use optical fan-outs and switches to direct light to specific WCDs. The first network is used to measure the light transit time out to each pair of detectors, and the second network sends light to each detector, calibrating the response times of the four PMTs within each detector. As the relative PMT response times are dependent on the number of photons in the light pulse, neutral density filters will be used to control the light intensity across five orders of magnitude. This system will run both continuously in a low-rate mode, and in a high-rate mode with many intensity levels. In this thesis, the design of the calibration system and systematic studies verifying its performance are presented.
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Rising fuel prices and environmental concerns are threatening the stability of current electrical grid systems. These factors are pushing the automobile industry towards more effcient, hybrid vehicles. Current trends show petroleum is being edged out in favor of electricity as the main vehicular motive force. The proposed methods create an optimized charging control schedule for all participating Plug-in Hybrid Electric Vehicles in a distribution grid. The optimization will minimize daily operating costs, reduce system losses, and improve power quality. This requires participation from Vehicle-to-Grid capable vehicles, load forecasting, and Locational Marginal Pricing market predictions. Vehicles equipped with bidirectional chargers further improve the optimization results by lowering peak demand and improving power quality.
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Erythropoietin (EPO) and iron deficiency as causes of anemia in patients with limited renal function or end-stage renal disease are well addressed. The concomitant impairment of red blood cell (RBC) survival has been largely neglected. Properties of the uremic environment like inflammation, increased oxidative stress and uremic toxins seem to be responsible for the premature changes in RBC membrane and cytoskeleton. The exposure of antigenic sites and breakdown of the phosphatidylserine asymmetry promote RBC phagocytosis. While the individual response to treatment with EPO-stimulating agents (ESA) depends on both the RBC's lifespan and the production rate, uniform dosing algorithms do not meet that demand. The clinical use of mathematical models predicting ESA-induced changes in hematocrit might be greatly improved once independent estimates of RBC production rate and/or lifespan become available, thus making the concomitant estimation of both parameters unnecessary. Since heme breakdown by the hemoxygenase pathway results in carbon monoxide (CO) which is exhaled, a simple CO breath test has been used to calculate hemoglobin turnover and therefore RBC survival and lifespan. Future research will have to be done to validate and implement this method in patients with kidney failure. This will result in new insights into RBC kinetics in renal patients. Eventually, these findings are expected to improve our understanding of the hemoglobin variability in response to ESA.
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MT Hard Water of Montana Tech of the University of Montana submits Task 3: Treatment Technology Validation for Water Softening Technology as an entry into the 2012 WERC Environmental Design Contest. Currently, there are several commercially available technologies that treat water hardness. The objective of this project is to develop a strategy to evaluate and validate different water hardness treatment technologies. MT Hard Water (MTHW) has studied several technologies including: electromagnetic water treatment, ion exchange, and reverse osmosis. For validation purposes, an electromagnetic water treatment system (ScaleRID) was selected according to the WERC task description.
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ABSTRACT: Meta-analyses are an essential tool of clinical research. Meta-analyses of individual randomized controlled trials frequently constitute the highest possible level of scientific evidence for a given research question and allow surgeons to rapidly gain a comprehensive understanding of an important clinical issue. Moreover, meta-analyses often serve as cornerstones for evidence-based surgery, treatment guidelines, and knowledge transfer. Given the importance of meta-analyses to the medical (and surgical) knowledge base, it is of cardinal importance that surgeons have a basic grasp of the principles that guide a high-quality meta-analysis, and be able to weigh objectively the advantages and potential pitfalls of this clinical research tool. Unfortunately, surgeons are often ill-prepared to successfully conduct, critically appraise, and correctly interpret meta-analyses. The objective of this educational review is to provide surgeons with a brief introductory overview of the knowledge and skills required for understanding and critically appraising surgical meta-analyses as well as assessing their implications for their own surgical practice.
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OBJECTIVE: Nursing in 'live islands' and routine high dose intravenous immunoglobulins after allogeneic hematopoietic stem cell transplantation were abandoned by many teams in view of limited evidence and high costs. METHODS: This retrospective single-center study examines the impact of change from nursing in 'live islands' to care in single rooms (SR) and from high dose to targeted intravenous immunoglobulins (IVIG) on mortality and infection rate of adult patients receiving an allogeneic stem cell or bone marrow transplantation in two steps and three time cohorts (1993-1997, 1997-2000, 2000-2003). RESULTS: Two hundred forty-eight allogeneic hematopoetic stem cell transplantations were performed in 227 patients. Patient characteristics were comparable in the three cohorts for gender, median age, underlying disease, and disease stage, prophylaxis for graft versus host disease (GvHD) and cytomegalovirus constellation. The incidence of infections (78.4%) and infection rates remained stable (rates/1000 days of neutropenia for sepsis 17.61, for pneumonia 6.76). Cumulative incidence of GvHD and transplant-related mortality did not change over time. CONCLUSIONS: Change from nursing in 'live islands' to SR and reduction of high dose to targeted IVIG did not result in increased infection rates or mortality despite an increase in patient age. These results support the current practice.
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Buildings and urban construction are understood in this paper as representations of the city. Their meanings, however, are often invisible, positing unrealized urban visions, which are both imbedded in and which call up chains of associations expressing desires and fears. Narratives of what the city should be often contain the rejection of the existing urban situation. Understanding architectural objects as potential underscores their imaginary nature. Freud, for example, uses the Roman ruins in Civilization and its Discontents (1929) as a means to imagine stages of history. Yet, meanings of the new can also be covered over and layered. Milan is a city with fragments of the new, which once projected an ideal urban space into the future. The potentiality of Milan’s postwar urban objects is analyzed in relationship to narratives of the city and insertion is framed as an imagining into the city.
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A fundamental assumption in invasion biology is that most invasive species exhibit enhanced performance in their introduced range relative to their home ranges. This idea has given rise to numerous hypotheses explaining “invasion success” by virtue of altered ecological and evolutionary pressures. There are surprisingly few data, however, testing the underlying assumption that the performance of introduced populations, including organism size, reproductive output, and abundance, is enhanced in their introduced compared to their native range. Here, we combined data from published studies to test this hypothesis for 26 plant and 27 animal species that are considered to be invasive. On average, individuals of these 53 species were indeed larger, more fecund, and more abundant in their introduced ranges. The overall mean, however, belied significant variability among species, as roughly half of the investigated species (N = 27) performed similarly when compared to conspecific populations in their native range. Thus, although some invasive species are performing better in their new ranges, the pattern is not universal, and just as many are performing largely the same across ranges.
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BACKGROUND Idiopathic pulmonary fibrosis (IPF) is characterized by formation and proliferation of fibroblast foci. Endothelin-1 induces lung fibroblast proliferation and contractile activity via the endothelin A (ETA) receptor. OBJECTIVE To determine whether ambrisentan, an ETA receptor-selective antagonist, reduces the rate of IPF progression. DESIGN Randomized, double-blind, placebo-controlled, event-driven trial. (ClinicalTrials.gov: NCT00768300). SETTING Academic and private hospitals. PARTICIPANTS Patients with IPF aged 40 to 80 years with minimal or no honeycombing on high-resolution computed tomography scans. INTERVENTION Ambrisentan, 10 mg/d, or placebo. MEASUREMENTS Time to disease progression, defined as death, respiratory hospitalization, or a categorical decrease in lung function. RESULTS The study was terminated after enrollment of 492 patients (75% of intended enrollment; mean duration of exposure to study medication, 34.7 weeks) because an interim analysis indicated a low likelihood of showing efficacy for the end point by the scheduled end of the study. Ambrisentan-treated patients were more likely to meet the prespecified criteria for disease progression (90 [27.4%] vs. 28 [17.2%] patients; P = 0.010; hazard ratio, 1.74 [95% CI, 1.14 to 2.66]). Lung function decline was seen in 55 (16.7%) ambrisentan-treated patients and 19 (11.7%) placebo-treated patients (P = 0.109). Respiratory hospitalizations were seen in 44 (13.4%) and 9 (5.5%) patients in the ambrisentan and placebo groups, respectively (P = 0.007). Twenty-six (7.9%) patients who received ambrisentan and 6 (3.7%) who received placebo died (P = 0.100). Thirty-two (10%) ambrisentan-treated patients and 16 (10%) placebo-treated patients had pulmonary hypertension at baseline, and analysis stratified by the presence of pulmonary hypertension revealed similar results for the primary end point. LIMITATION The study was terminated early. CONCLUSION Ambrisentan was not effective in treating IPF and may be associated with an increased risk for disease progression and respiratory hospitalizations. PRIMARY FUNDING SOURCE Gilead Sciences.
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This Trans-Himalayan tale unites two narratives, an historical account of scholarly thinking regarding linguistic phylogeny in eastern Eurasia alongside a reconstruction of the ethnolinguistic prehistory of eastern Eurasia based on linguistic and human population genetic phylogeography. The first story traces the tale of transformation in thought regarding language relationships in eastern Eurasia from Tibeto-Burman to Trans-Himalayan. The path is strewn with defunct family trees such as Indo-Chinese, Sino-Tibetan, Sino-Himalayan and Sino-Kiranti. In the heyday of racism in scholarship, Social Darwinism coloured both language typology and the phylogenetic models of language relationship in eastern Eurasia. Its influential role in the perpetuation of the Indo-Chinese model is generally left untold. The second narrative presents a conjectural reconstruction of the ethnolinguistic prehistory of eastern Eurasia based on possible correlations between genes and language communities. In so doing, biological ancestry and linguistic affinity are meticulously distinguished, a distinction which the language typologists of yore sought to blur, although the independence of language and race was stressed time and again by prominent historical linguists.
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CONTEXT Dementia care giving can lead to increased stress, physical and psychosocial morbidity, and mortality. Anecdotal evidence suggests that hospice care provided to people with dementia and their caregivers may buffer caregivers from some of the adverse outcomes associated with family caregiving in Alzheimer's Disease (AD). OBJECTIVES This pilot study examined psychological and physical outcomes among 32 spousal caregivers of patients with AD. It was hypothesized that caregivers who utilized hospice services would demonstrate better outcomes after the death of their spouse than caregivers who did not utilize hospice. METHODS The charts of all spousal caregivers enrolled in a larger longitudinal study from 2001 to 2006 (N=120) were reviewed, and participants whose spouse had died were identified. Of these, those who received hospice care (n=10) were compared to those who did not (n=22) for various physiological and psychological measures of stress, both before and after the death of the care recipient. An Analysis of Covariance (ANCOVA), with postdeath scores as the dependent variable and pre-death scores as covariates, was used for all variables. RESULTS Significant group differences were found in postdeath depressive symptoms (HAM-D; F(1,29)=6.10, p<0.05) and anxiety symptoms (HAM-A; F(1,29)=5.71, p<0.05). Most psychological outcome variables demonstrated moderate effect sizes with a Cohen's d of>0.5 between groups. CONCLUSIONS These data suggest that hospice enrollment may ameliorate the detrimental psychological effects in caregivers who have lost a spouse with Alzheimer's Disease. Based on these pilot data, further prospective investigation is warranted.
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BACKGROUND: Congenital diaphragmatic hernia (CDH) remains a significant cause of death in newborns. With advances in neonatal critical care and ventilation strategies, survival in the term infant now exceeds 80% in some centers. Although prematurity is a significant risk factor for morbidity and mortality in most neonatal diseases, its associated risk with infants with CDH has been described poorly. We sought to determine the impact of prematurity on survival using data from the Congenital Diaphragmatic Hernia Registry (CDHR). METHODS: Prospectively collected data from live-born infants with CDH were analyzed from the CDHR from January 1995 to July 2009. Preterm infants were defined as <37 weeks estimated gestational age at birth. Univariate and multivariate logistic regression analysis were>performed. RESULTS: During the study period, 5,069 infants with CDH were entered in the registry. Of the 5,022 infants with gestational age data, there were 3,895 term infants (77.6%) and 1,127 preterm infants (22.4%). Overall survival was 68.7%. A higher percentage of term infants were treated with extracorporeal membrane oxygenation (ECMO) (33% term vs 25.6% preterm). Preterm infants had a greater percentage of chromosomal abnormalities (4% term vs 8.1% preterm) and major cardiac anomalies (6.1% term vs 11.8% preterm). Also, a significantly higher percentage of term infants had repair of the hernia (86.3% term vs 69.4% preterm). Survival for infants that underwent repair was high in both groups (84.6% term vs 77.2% preterm). Survival decreased with decreasing gestational age (73.1% term vs 53.5% preterm). The odds ratio (OR) for death among preterm infants adjusted for patch repair, ECMO, chromosomal abnormalities, and major cardiac anomalies was OR 1.68 (95% confidence interval [CI], 1.34-2.11). CONCLUSION: Although outcomes for preterm infants are clearly worse than in the term infant, more than 50% of preterm infants still survived. Preterm infants with CDH remain a high-risk group. Although ECMO may be of limited value in the extremely premature infant with CDH, most preterm infants that live to undergo repair will survive. Prematurity should not be an independent factor in the treatment strategies of infants with CDH.
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BACKGROUND: Pediatric truncal vascular injuries occur infrequently and have a reported mortality rate of 30% to 50%. This report examines the demographics, mechanisms of injury, associated trauma, and outcome of patients presenting for the past 10 years at a single institution with truncal vascular injuries. METHODS: A retrospective review (1997-2006) of a pediatric trauma registry at a single institution was undertaken. RESULTS: Seventy-five truncal vascular injuries occurred in 57 patients (age, 12 +/- 3 years); the injury mechanisms were penetrating in 37%. Concomitant injuries occurred with 76%, 62%, and 43% of abdominal, thoracic, and neck vascular injuries, respectively. Nonvascular complications occurred more frequently in patients with abdominal vascular injuries who were hemodynamically unstable on presentation. All patients with thoracic vascular injuries presenting with hemodynamic instability died. In patients with neck vascular injuries, 1 of 2 patients who were hemodynamically unstable died, compared to 1 of 12 patients who died in those who presented hemodynamically stable. Overall survival was 75%. CONCLUSIONS: Survival and complications of pediatric truncal vascular injury are related to hemodynamic status at the time of presentation. Associated injuries are higher with trauma involving the abdomen.