Sub-Microarcsecond Astrometry with SIM-Lite: A Testbed-based Performance Assessment

SIM-Lite is an astrometric interferometer being designed for sub-microarcsecond astrometry, with a wide range of applications from searches for Earth-analogs to determining the distribution of dark matter. SIM-Lite measurements can be limited by random and systematic errors, as well as astrophysical noise. In this paper we focus on instrument systematic errors and report results from SIM-Lite's interferometer testbed. We find that, for narrow-angle astrometry such as used for planet finding, the end-of-mission noise floor for SIM-Lite is below 0.035 uas.Comment: 5 pages, 5 figure

What could be learnt from Positronium for Quarkonium?

In order to fulfill Low's theorem requirements, a new lowest order basis for bound state decay computations is proposed, in which the binding energy is treated non-perturbatively. The properties of the method are sketched by reviewing standard positronium decay processes. Then, it is shown how applying the method to quarkonia sheds new light on some longstanding puzzles.Comment: 12 pages, 10 figures. Talk given at the ETH Workshop on Positronium Physics, May 30-31, 2003, Zurich, Switzerlan

Search for color-suppressed B hadronic decay processes at the Υ(4S) resonance

Using 3.1fb^(-1) of data accumulated at the Υ(4S) by the CLEO-II detector, corresponding to 3.3×10^6 BB̅ pairs, we have searched for the color-suppressed B hadronic decay processes B^(0) → D^(0)(D^(*0))X^0, where X^0 is a light neutral meson π^0, ρ^0, η, η′ or ω. The D^(*0) mesons are reconstructed in D^(*0) → D^(0)π^(0) and the D^0 mesons in D^(0) → K^(-)π^(+), K^(-)π^(+)π^(0) and K^(-)π^(+)π^(+)π^(-) decay modes. No obvious signal is observed. We set 90% C.L. upper limits on these modes, varying from 1.2×10^(-4) for B^(0) → D^(0)π^(0) to 1.9×10^(-3) for B^(0) → D^(*0)η′

Effects of cadmium on morphological structure of sperm in Caspiomyzon wagneri (Kessler, 1870) (Petromyzontiformes : Petromyzontidae)

The present study aimed to investigate effects of the heavy metal Cd on the sperm morphological indices of Caspimyzon wagneri. The sperm were exposed to 0.01, 0.1, 1, 10, 100 and 1000 mg.L-1 Cd for three minutes, three and 36 hours. The sperms exposed to Cd showed an increase in the length, width and surface of the head, flagella degradation and slightly flagella breakage. With increase of Cd concentration or the exposure duration, the damages found in sperms increased. But when exposure to contaminant exceeds than certain period of time,damage effects caused changes in the sperm structure as head length reduction and head width increasing and thereby reducing the sperm’s head surface, complete cutting of flagella at all samples and deformation of the sperm’s head from oval to circular, which these changes became visible during 36 hours of exposure to cadmium.Therefore, the results revealed that the arrival of pollutants including cadmium to the natural reproduction ground of this species due to induction the harmful effects on sperm morphology factors will have adverse effects on sperm function and fertilization rate and reduce them, and as such will be considered a serious threat to the survival generation of this rare species

Finite element study of deformation behaviour of Al- 6063 alloy developed by equal channel angular extrusion

The objective of this work is to evaluate the equivalent plastic strain levels induced by equal channel angular extrusion (ECAE) in an annealed Al-6063 alloy after six passes at a temperature of 200°C following route A with a constant ram speed of 30 mm/min through a die angle of 90° between the die channels using the finite element method (FEM). ECAE process is simulated using the DEFORM-3D software through a three-dimensional analysis. Grain refinement is simulated by forcing the element size to zero. It is found that for a very fine mesh the PEEQ converges to 1.046

Comparison of normal values of Duplex indices of vertebral arteries in young and elderly adults

<p>Abstract</p> <p>Background</p> <p>Considering the role of aging in brain atrophy and cerebral vascular demand, we carried out this study to clarify the role of aging in duplex indices of vertebral arteries.</p> <p>Methods</p> <p>From June 2005 to June 2006, 96 volunteers with age range of 20 to 95 years, were evaluated with color doppler for duplex indices of vertebral arteries. Sever hemodynamic stenosis was excluded in all of these patients. These volunteers were subdivided in two groups: younger and older than 60 year old. In all of these patients we measured diameter, peak systolic velocity (PSV), resistive index (RI), and flow volume (FV) of vertebral arteries in right and left sides.</p> <p>Results</p> <p>There was no significant difference in diameter, PSV, RI and FV between two groups. We have clarified that in patients younger than 60 year old, comparing right and left vertebral arteries, PSV and FV were higher in left side.</p> <p>Conclusion</p> <p>Duplex indices of vertebral arteries are age independent in adults.</p

A Prospective Study on Risk Factors for Acute Kidney Injury and All-Cause Mortality in Hospitalized COVID-19 Patients From Tehran (Iran)

Background: Several reports suggested that acute kidney injury (AKI) is a relatively common occurrence in hospitalized COVID-19 patients, but its prevalence is inconsistently reported across different populations. Moreover, it is unknown whether AKI results from a direct infection of the kidney by SARS-CoV-2 or it is a consequence of the physiologic disturbances and therapies used to treat COVID-19. We aimed to estimate the prevalence of AKI since it varies by geographical settings, time periods, and populations studied and to investigate whether clinical information and laboratory findings collected at hospital admission might influence AKI incidence (and mortality) in a particular point in time during hospitalization for COVID-19. Methods: Herein we conducted a prospective longitudinal study investigating the prevalence of AKI and associated factors in 997 COVID-19 patients admitted to the Baqiyatallah general hospital of Tehran (Iran), collecting both clinical information and several dates (of: birth; hospital admission; AKI onset; ICU admission; hospital discharge; death). In order to examine how the clinical factors influenced AKI incidence and all-cause mortality during hospitalization, survival analysis using the Cox proportional-hazard models was adopted. Two separate multiple Cox regression models were fitted for each outcome (AKI and death). Results: In this group of hospitalized COVID-19 patients, the prevalence of AKI was 28.5% and the mortality rate was 19.3%. AKI incidence was significantly enhanced by diabetes, hyperkalemia, higher levels of WBC count, and blood urea nitrogen (BUN). COVID-19 patients more likely to die over the course of their hospitalization were those presenting a joint association between ICU admission with either severe COVID-19 or even mild/moderate COVID-19, hypokalemia, and higher levels of BUN, WBC, and LDH measured at hospital admission. Diabetes and comorbidities did not increase the mortality risk among these hospitalized COVID-19 patients. Conclusions: Since the majority of patients developed AKI after ICU referral and 40% of them were admitted to ICU within 2 days since hospital admission, these patients may have been already in critical clinical conditions at admission, despite being affected by a mild/moderate form of COVID-19, suggesting the need of early monitoring of these patients for the onset of eventual systemic complications

Information technology issues in healthcare: Hospital CEO and CIO perspectives.

Healthcare Information Technology (HIT) is widely regarded as a key to improving the quality of healthcare in the United States and potentially reducing its cost. Yet, its implementation is a continuous challenge for the healthcare industry. In this article, we report the results of a survey distributed to CEOs and CIOs at 1400 U.S. hospitals regarding their perceptions of the key information technology (IT) issues in healthcare. Among the top ten issues, the implementation of electronic medical records is ranked the highest. Included in the top ten are issues related to: improving healthcare quality by the use of information technology; change management, privacy, security, and accuracy of electronic records; and decision support applications. While some differences existed, we found much similarity between the views of the CEOs and the CIOs with both groups being characterized as conservative and risk-averse in their entrepreneurial orientation. No major differences were observed between urban and rural hospitals, or large and small hospitals. Given the heightened interest in healthcare IT, these results have wide implications for many stakeholders in this burgeoning industr