Superfluid Helium Tanker (SFHT) study

Replenishment of superfluid helium (SFHe) offers the potential of extending the on-orbit life of observatories, satellite instruments, sensors and laboratories which operate in the 2 K temperature regime. A reference set of resupply customers was identified as representing realistic helium servicing requirements and interfaces for the first 10 years of superfluid helium tanker (SFHT) operations. These included the Space Infrared Telescope Facility (SIRTF), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (Astromag), and the Microgravity and Materials Processing Sciences Facility (MMPS)/Critical Point Phenomena Facility (CPPF). A mixed-fleet approach to SFHT utilization was considered. The tanker permits servicing from the Shuttle cargo bay, in situ when attached to the OMV and carried to the user spacecraft, and as a depot at the Space Station. A SFHT Dewar ground servicing concept was developed which uses a dedicated ground cooling heat exchanger to convert all the liquid, after initial fill as normal fluid, to superfluid for launch. This concept permits the tanker to be filled to a near full condition, and then cooled without any loss of fluid. The final load condition can be saturated superfluid with any desired ullage volume, or the tank can be totally filed and pressurized. The SFHT Dewar and helium plumbing system design has sufficient component redundancy to meet fail-operational, fail-safe requirements, and is designed structurally to meet a 50 mission life usage requirement. Technology development recommendations were made for the selected SFHT concept, and a Program Plan and cost estimate prepared for a phase C/D program spanning 72 months from initiation through first launch in 1997

High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey

The SkyMapper Southern Sky Survey is carrying out a search for the most metal-poor stars in the Galaxy. It identifies candidates by way of its unique filter set that allows for estimation of stellar atmospheric parameters. The set includes a narrow filter centered on the Ca II K 3933A line, enabling a robust estimate of stellar metallicity. Promising candidates are then confirmed with spectroscopy. We present the analysis of Magellan-MIKE high-resolution spectroscopy of 122 metal-poor stars found by SkyMapper in the first two years of commissioning observations. 41 stars have [Fe/H] <= -3.0. Nine have [Fe/H] <= -3.5, with three at [Fe/H] ~ -4. A 1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba and Eu shows these stars have [X/Fe] ratios typical of other halo stars. One star with low [X/Fe] [X/Fe values appears to be "Fe-enhanced," while another star has an extremely large [Sr/Ba] ratio: >2. Only one other star is known to have a comparable value. Seven stars are "CEMP-no" stars ([C/Fe] > 0.7, [Ba/Fe] < 0). 21 stars exhibit mild r-process element enhancements (0.3 <=[Eu/Fe] < 1.0), while four stars have [Eu/Fe] >= 1.0. These results demonstrate the ability to identify extremely metal-poor stars from SkyMapper photometry, pointing to increased sample sizes and a better characterization of the metal-poor tail of the halo metallicity distribution function in the future.Comment: Minor corrections to text, missing data added to Tables 3 and 4; updated to match published version. Complete tables included in sourc

Generating Bijections between HOAS and the Natural Numbers

A provably correct bijection between higher-order abstract syntax (HOAS) and the natural numbers enables one to define a "not equals" relationship between terms and also to have an adequate encoding of sets of terms, and maps from one term family to another. Sets and maps are useful in many situations and are preferably provided in a library of some sort. I have released a map and set library for use with Twelf which can be used with any type for which a bijection to the natural numbers exists. Since creating such bijections is tedious and error-prone, I have created a "bijection generator" that generates such bijections automatically together with proofs of correctness, all in the context of Twelf.Comment: In Proceedings LFMTP 2010, arXiv:1009.218

Increased left ventricular mass is a risk factor for the development of a depressed left ventricular ejection fraction within five years The Cardiovascular Health Study

AbstractObjectivesOur aim in this study was to determine whether increased left ventricular mass (LVM) is a risk factor for the development of a reduced left ventricular ejection fraction (LVEF).BackgroundPrior studies have shown that increased LVM is a risk factor for heart failure but not whether it is a risk factor for a low LVEF.MethodsAs part of the Cardiovascular Health Study, a prospective population-based longitudinal study, we performed echocardiograms upon participant enrollment and again at follow-up of 4.9 ± 0.14 years. In the present analysis, we identified 3,042 participants who had at baseline a normal LVEF and an assessment of LVM (either by electrocardiogram or echocardiogram), and at follow-up a measurable LVEF. The frequency of the development of a qualitatively depressed LVEF on two-dimensional echocardiography, corresponding approximately to an LVEF <55%, was analyzed by quartiles of baseline LVM. Multivariable regression determined whether LVM was independently associated with the development of depressed LVEF.ResultsBaseline quartile of echocardiographic LVM indexed to body surface area was associated with development of a depressed LVEF (4.8% in quartile 1, 4.4% in quartile 2, 7.5% in quartile 3, and 14.1% in quartile 4 [p < 0.001]). A similar relationship was seen in the subgroup of participants without myocardial infarction (p < 0.001). In multivariable regression that adjusted for confounders, both baseline echocardiographic (p < 0.001) and electrocardiographic (p < 0.001) LVM remained associated with development of depressed LVEF.ConclusionsIncreased LVM as assessed by electrocardiography or echocardiography is an independent risk factor for the development of depressed LVEF

Global and nonglobal parameters of horizontal-branch morphology of globular clusters

The horizontal-branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost the same metallicity exhibit different HB morphologies demonstrates that at least one more parameter is needed t

Rural Zambian Oral Health Transition: A Long-Term Retrospective Examination of an Outreach Program’s Progress and Impact

Objective: This study aimed to (a) describe an annual prevention-focused, community-based oral health outreach program in rural Zambia, (b) assess its oral health outcomes using demographic and oral health variables, and c) identify milestones resulting from program activities. Methods: A retrospective analysis of demographic and oral health data from a single site between 2007–2014 and 2018–2019 was conducted. Demographic variables included sex and age, while clinical outcomes encompassed pain, untreated caries, and treatment urgency. Bivariate and multivariable analyses were performed, adjusting for sex and age categories. Information on community development was obtained from the Ministry of Health and local community representatives. Results: Data from 5,791 subjects were analyzed. The prevalence of pain, untreated caries, and highest treatment urgency category decreased consistently across year categories. Both bivariate and multivariable analyses showed statistically significant differences in clinical outcomes between year categories (p < 0.001). In addition, the percentage of male participants and younger age categories increased during the study period. Key program milestones included the installation of two boreholes for clean water, the development of a local community oral health volunteer program, the establishment of an educational pipeline by the Dental Training School for residents, and the construction of a maternal/oral health center with district and ministry oversight. Conclusion: The observed decrease in treatment urgency scores, presence of pain, and untreated caries are consistent with the prevention-seeking behavior of program participants. The increasing participation and changing demographic patterns over time suggest a growing demand for oral health services among males and younger individuals. The positive oral health outcomes and development of a maternal child/oral health facility exemplify a program design aligned with community needs and appropriate care delivery

The association of admission blood glucose level with the clinical picture and prognosis in cardiogenic shock - Results from the CardShock Study

Background: Critically ill patients often present with hyperglycemia, regardless of previous history of diabetes mellitus (DM). Hyperglycemia has been associated with adverse outcome in acute myocardial infarction and acute heart failure. We investigated the association of admission blood glucose level with the clinical picture and short-term mortality in cardiogenic shock (CS). Methods: Consecutively enrolled CS patients were divided into five categories according to plasma glucose level at the time of enrolment: hypoglycemia (glucose = 16.0 mmol/L) hyperglycemia. Clinical presentation, biochemistry, and short-term mortality were compared between the groups. Results: Plasma glucose level of 211 CS patients was recorded. Glucose levels were distributed equally between normoglycemia (26% of patients), mild (27%), moderate (19%) and severe (25%) hyperglycemia, while hypoglycemia (2%) was rare. Severe hyperglycemia was associated with higher blood leukocyte count (17.3 (5.8) E9/L), higher lactate level (4.4 (3.3-8.4) mmol/L) and lower arterial pH (7.23 (0.14)) compared with normoglycemia or mild to moderate hyperglycemia (p <0.001 for all). In-hospital mortality was highest among hypoglycemic (60%) and severely hyperglycemic (56%) patients, compared with 22% in normoglycemic group (p <0.01). Severe hyperglycemia was an independent predictor of in-hospital mortality (OR 3.7, 95% CI 1.19-11.7, p = 0.02), when adjusted for age, gender, LVEF, lactate, and DM. Conclusions: Admission blood glucose level has prognostic significance in CS. Mortality is highest among patients with severe hyperglycemia or hypoglycemia. Severe hyperglycemia is independently associated with high in-hospital mortality in CS. It is also associated with biomarkers of systemic hypoperfusion and stress response. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

Altered mental status predicts mortality in cardiogenic shock - results from the CardShock study

Background: Altered mental status is among the signs of hypoperfusion in cardiogenic shock, the most severe form of acute heart failure. The aim of this study was to investigate the prevalence of altered mental status, to identify factors associating with it, and to assess the prognostic significance of altered mental status in cardiogenic shock. Methods: Mental status was assessed at presentation of shock in 215 adult cardiogenic shock patients in a multinational, prospective, observational study. Clinical picture, biochemical variables, and short-term mortality were compared between patients presenting with altered and normal mental status. Results: Altered mental status was detected in 147 (68%) patients, whereas 68 (32%) patients had normal mental status. Patients with altered mental status were older (68 vs. 64 years, p=0.04) and more likely to have an acute coronary syndrome than those with normal mental status (85% vs. 74%, p=0.04). Altered mental status was associated with lower systolic blood pressure (76 vs. 80 mmHg, p=0.03) and lower arterial pH (7.27 vs. 7.35, p Conclusions: Altered mental status is a common clinical sign of systemic hypoperfusion in cardiogenic shock and is associated with poor outcome. It is also associated with several biochemical findings that reflect inadequate tissue perfusion, of which low arterial pH is independently associated with altered mental status.Peer reviewe

Time Evolution via S-branes

Using S(pacelike)-branes defined through rolling tachyon solutions, we show how the dynamical formation of D(irichlet)-branes and strings in tachyon condensation can be understood. Specifically we present solutions of S-brane actions illustrating the classical confinement of electric and magnetic flux into fundamental strings and D-branes. The role of S-branes in string theory is further clarified and their RR charges are discussed. In addition, by examining ``boosted'' S-branes, we find what appears to be a surprising dual S-brane description of strings and D-branes, which also indicates that the critical electric field can be considered as a self-dual point in string theory. We also introduce new tachyonic S-branes as Euclidean counterparts to non-BPS branes.Comment: 62 pages, 10 figures. v2 references adde