878 research outputs found

    Telecommunications system design for the Mariner Mars 1971 spacecraft

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    The configuration of the Mariner Mars 1971 spacecraft telecommunications system is detailed, with particular attention to modifications performed to accommodate the orbital mission. The analysis and planning for launching are also discussed

    Decay of Reactivity Induced by Simulated Solar Wind Implantation of a Forsteritic Olivine

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    In returning humans to the Moon, the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) must address many problems faced by the original Apollo astronauts. Major among these is control of the fine dust (<20 microns) that makes up approx.20 wt% portion of the lunar surface. This ubiquitous, clinging, sharp, abrasive, glassy dust caused a plethora of problems with seals, abrasion, and coatings, in addition to possible health problems, including lunar dust hayfever. The lifetime of reactive sites on the surfaces of irradiated lunar dust grains is of interest to those studying human health because of the free radicals and toxic compounds that may be formed and may not passivate quickly when exposed to habitat/spacecraft air

    Capsular polysaccharide production and serum survival of Vibrio vulnificus are dependent on antitermination control by RfaH

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    © 2016 Federation of European Biochemical Societies The human pathogen Vibrio vulnificus undergoes phase variation among colonial morphotypes, including a virulent opaque form which produces capsular polysaccharide (CPS) and a translucent phenotype that produces little or no CPS and is attenuated. Here, we found that a V. vulnificus mutant defective for RfaH antitermination control showed a diminished capacity to undergo phase variation and displayed significantly reduced distal gene expression within the Group I CPS operon. Moreover, the rfaH mutant produced negligible CPS and was highly sensitive to killing by normal human serum, results which indicate that RfaH is likely essential for virulence in this bacterium

    The relation of C - reactive protein to chronic kidney disease in African Americans: the Jackson Heart Study

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    <p>Abstract</p> <p>Background</p> <p>African Americans have an increased incidence and worse prognosis with chronic kidney disease (CKD - estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m<sup>2</sup>) than their counterparts of European-descent. Inflammation has been related to renal disease in non-Hispanic whites, but there are limited data on the role of inflammation in renal dysfunction in African Americans in the community.</p> <p>Methods</p> <p>We examined the cross-sectional relation of log transformed C-reactive protein (CRP) to renal function (eGFR by Modification of Diet and Renal Disease equation) in African American participants of the community-based Jackson Heart Study's first examination (2000 to 2004). We conducted multivariable linear regression relating CRP to eGFR adjusting for age, sex, body mass index, systolic and diastolic blood pressure, diabetes, total/HDL cholesterol, triglycerides, smoking, antihypertensive therapy, lipid lowering therapy, hormone replacement therapy, and prevalent cardiovascular disease events. In a secondary analysis we assessed the association of CRP with albuminuria (defined as albumin-to-creatinine ratio > 30 mg/g).</p> <p>Results</p> <p>Participants (n = 4320, 63.2% women) had a mean age ± SD of 54.0 ± 12.8 years. The prevalence of CKD was 5.2% (n = 228 cases). In multivariable regression, CRP concentrations were higher in those with CKD compared to those without CKD (mean CRP 3.2 ± 1.1 mg/L vs. 2.4 ± 1.0 mg/L, respectively p < 0.0001). CRP was significantly associated with albuminuria in sex and age adjusted model however not in the multivariable adjusted model (p > 0.05).</p> <p>Conclusion</p> <p>CRP was associated with CKD however not albuminuria in multivariable-adjusted analyses. The study of inflammation in the progression of renal disease in African Americans merits further investigation.</p

    The Relation of Diabetes, Impaired Fasting Blood Glucose, and Insulin Resistance to Left Ventricular Structure and Function in African Americans: The Jackson Heart Study

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    OBJECTIVE We assessed the relation of diabetes and insulin resistance (IR) on left ventricular (LV) structure and function in African Americans. RESEARCH DESIGN AND METHODS Among those receiving echocardiograms in cycle 1 of the Jackson Heart Study, we assessed the sex-specific relation of fasting blood glucose (FBG), diabetes, and IR to LV structure and function, adjusting for age, systolic blood pressure, antihypertensive medications, and BMI. RESULTS Among 2,399 participants, LV mass index (Pwomen = 0.0002 and Pmen = 0.02), posterior wall thickness (Pwomen = 0.01 and Pmen = 0.05), and interventricular septal wall thickness (Pwomen = 0.01) were related to FBG categories. Among those with normal FBG and no diabetes, concentric remodeling and low ejection fraction in women and LV mass index and posterior wall thickness in men were related to IR. CONCLUSIONS In the largest study of its kind in a community-based cohort of African Americans, we found a relation of FBG category and IR to LV structure and function

    Currency depreciation and the monetary adjustment process: Reconsidering Lord King's contributions

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    © Oxford University Press 2018, All rights reserved. This paper investigates Lord King's contributions in light of the renewed debate on international monetary policy coordination. We argue that King's work contains refined bullionist insights concerning currency depreciation, exchange rate determination, and balance of payments adjustment. We show how King's analysis of the monetary process under different currency regimes can help elucidate the effects of unconventional monetary policy on a global scale, concerning monetary spillovers, currency wars, business cycles, and the distribution of wealth

    Delayed bedtime due to screen time in schoolchildren: Importance of area deprivation

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    Background Sleep duration is an important predictor of obesity and health. This study evaluated the association between late bedtime and screen time, and the role of geographical deprivation in English schoolchildren. Methods We collected bedtime and waking time, screen time, sociodemographic data and measured body mass index in a cross-section of 1332 11-15-year-old schoolchildren (45.7% female) participating in the East of England healthy heart study. Logistic regression was used to determine the likelihood of late bedtime in schoolchildren with different screen time and from a different geographic location. Mean differences were assessed either on ANOVA or t-test. Results Approximately 42% of boys went to bed late at night compared with 37% of girls. When compared to those with 4 h of daily screen time were most likely to go to sleep late at night (OR, 1.97; 95%CI: 1.34-2.89). Late bedtime was associated with deprivation in schoolchildren. Conclusions High screen time and deprivation may explain lateness in bedtime in English schoolchildren. This explanation may vary according to area deprivation and geographic location. Family-centered interventions and parental support are important to reduce screen time, late bedtime and increase sleep duration

    Application of graph theory to the morphological analysis of settlements

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    In the following paper, the analyses of morphology of settlements were conducted using graph methods. The intention of the author was to create a quantifiable and simple measure, which, in a quantitative way, would express the degree of development of a graph (the spatial pattern of settlement). When analysing examples of graphs assigned to a set of small towns and large villages, it was noticed that the graph development index should depend on: a relative number of edges in relation to the number of nodes (β index), the number of cycles (urban blocks), which evidences the complexity of the spatial pattern of settlement, and the average rank of nodes of a graph, which expresses the degree of complexity of a street network
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