Radio astronomy Explorer-B in-flight mission control system development effort

A description is given of the development for the Mission Analysis Evaluation and Space Trajectory Operations (MAESTRO) program to be used for the in-flight decision making process during the translunar and lunar orbit adjustment phases of the flight of the Radio Astronomy Explorer-B. THe program serves two functions: performance and evaluation of preflight mission analysis, and in-flight support for the midcourse and lunar insertion command decisions that must be made by the flight director. The topics discussed include: analysis of program and midcourse guidance capabilities; methods for on-line control; printed displays of the MAESTRO program; and in-flight operational logistics and testing

Expression and Circular Dichroism Studies of the Extracellular Domain of the alpha Subunit of the Nicotinic Acetylcholine Receptor

To provide material suitable for structural studies of the nicotinic acetylcholine receptor, we have expressed and purified the NH2-terminal extracellular domain of the mouse muscle alpha subunit. Several constructs were initially investigated using Xenopus oocytes as a convenient small scale expression system. A fusion protein (alpha210GPI) consisting of the 210 NH2-terminal amino acids of the alpha subunit and a glycosylphosphatidylinositol anchorage sequence conferred surface alpha-bungarotoxin binding in oocytes. Coexpression of alpha210GPI with an analogous construct made from the delta subunit showed no evidence of heterodimer formation. The alpha210GPI protein was chosen for large scale expression in transfected Chinese hamster ovary cells. The alpha210GPI protein was cleaved from these cells and purified on an immunoaffinity column. Gel and column chromatography show that the purified protein is processed as expected and exists as a monomer. The purified protein also retains the two distinct, conformation-specific binding sites expected for the correctly folded alpha subunit. Circular dichroism studies of alpha210GPI suggest that this region of the receptor includes considerable beta-sheet secondary structure, with a small proportion of alpha-helix

High prevalence of double Plasmodium falciparum dhfr mutations at codons 108 and 59 in the Sistan-Baluchistan province, Iran

info:eu-repo/semantics/publishedVersio

Non-LTE Monte Carlo Radiative Transfer: II. Non-Isothermal Solutions for Viscous Keplerian Disks

We discuss the basic hydrodynamics that determines the density structure of the disks around hot stars. Observational evidence supports the idea that these disks are Keplerian (rotationally supported) gaseous disks. A popular scenario in the literature, which naturally leads to the formation of Keplerian disks, is the viscous decretion model. According to this scenario, the disks are hydrostatically supported in the vertical direction, while the radial structure is governed by the viscous transport. This suggests that the temperature is one primary factor that governs the disk density structure. In a previous study we demonstrated, using 3-D NLTE Monte Carlo simulations, that viscous keplerian disks can be highly non-isothermal. In this paper we build upon our previous work and solve the full problem of the steady-state non-isothermal viscous diffusion and vertical hydrostatic equilibrium. We find that the self-consistent solution departs significantly from the analytic isothermal density, with potentially large effects on the emergent spectrum. This implies that non-isothermal disk models must be used for a detailed modeling of Be star disks.Comment: 22 pages, 9 figures, Ap

2-D Radiative Transfer in Protostellar Envelopes: I. Effects of Geometry on Class I Sources

We present 2-D radiation transfer models of Class I Protostars and show the effect of including more realistic geometries on the resulting spectral energy distributions and images. We begin with a rotationally flattened infalling envelope as our comparison model, and add a flared disk and bipolar cavity. The disk affects the spectral energy distribution most strongly at edge-on inclinations, causing a broad dip at about 10 um (independent of the silicate feature) due to high extinction and low scattering albedo in this wavelength region. The bipolar cavities allow more direct stellar+disk radiation to emerge into polar directions, and more scattering radiation to emerge into all directions. The wavelength-integrated flux, often interpreted as luminosity, varies with viewing angle, with pole-on viewing angles seeing 2-4 times as much flux as edge-on, depending on geometry. Thus, observational estimates of luminosity should take into account the inclination of a source. The envelopes with cavities are significantly bluer in near-IR and mid-IR color-color plots than those without cavities. Using 1-D models to interpret Class I sources with bipolar cavities would lead to an underestimate of envelope mass and an overestimate of the implied evolutionary state. We compute images at near-, mid-, and far-IR wavelengths. We find that the mid-IR colors and images are sensitive to scattering albedo, and that the flared disk shadows the midplane on large size scales at all wavelengths plotted. Finally, our models produce polarization spectra which can be used to diagnose dust properties, such as albedo variations due to grain growth. Our results of polarization across the 3.1 um ice feature agree well with observations for ice mantles covering 5% of the radius of the grains.Comment: Accepted for publication in ApJ, 37 pages, 13 figures (several figures reduced in quality; find original version at http://gemelli.colorado.edu/~bwhitney/preprints.html

Micronutrient and iron supplementation and effective anti-malarial treatment synergistically improve childhood anaemia

The control of childhood anaemia in malaria holoendemic areas is a major public health challenge for which an optimal strategy remains to be determined. Malaria prevention may compromise the development of partial immunity. Regular micronutrient supplementation has been suggested as an alternative but its effectiveness remains unsettled. We therefore conducted a randomised placebo-controlled intervention trial with 207 Tanzanian children aged 5 months to 3 years on the efficacy of supervised supplementation of low-dose micronutrients including iron (Poly Vi-Sol with iron) three times per week, with an average attendance of ≥ 90%. The mean haemoglobin (Hb) level increased by 8 g/l more in children on supplement (95% CI 3-12) during the 5-month study. All age groups benefited from the intervention including severely anaemic subjects. The mean erythrocyte cell volume (MCV) increased but Hb in children ≥ 24 months improved independently of MCV and no relation was found with hookworm infection. The data therefore suggest that micronutrients other than iron also contributed to Hb improvement. In the supplement group of children who had received sulfadoxine-pyrimethamine (SP) treatment, the mean Hb level increased synergistically by 22 g/l (95% CI 13-30) compared to 7 g/l (95% CI 3-10) in those without such treatment. Supplementation did not affect malaria incidence. In conclusion, micronutrient supplementation improves childhood anaemia in malaria holoendemic areas and this effect is synergistically enhanced by temporary clearance of parasitaemia