324 research outputs found
A Novel Scheme of an Optimal Data Rate Transmission for Airborne Telemetry of Long Range Aerospace Vehicle
Airborne telemetry data is inevitable during the development phase of an aerospace vehicle. With the availability of telemetry data the vehicle characteristics are evaluated and the vehicle objectives are achieved subsequently. During the trajectory path, the airborne telemetry system transmits vehicle data continuously and ground receiving station receives it. The availability of data at ground station is solely dependent on various parameters; primarily data rate, modulation, RF power, etc. In this paper, typical data rate of telemetry for long range aerospace vehicle is analyzed and an innovative scheme is proposed for optimal data rate transmission with multi-resolution of high speed image data for distributed telemetry system. The scheme is implemented on 25 nm ZYNQ CSOC of telemetry hardware and synthesized netlist is simulated, performance is evaluated and results verified on telemetry hardware
Mechanical Ventilator for Delivery of 17O2 in Brief Pulses
The 17O nucleus has been used recently by several groups for magnetic resonance (MR) imaging of cerebral metabolism. Inhalational delivery of 17O2 in very brief pulses could, in theory, have significant advantages for determination of the cerebral metabolic rate for oxygen (CMRO2) with MR imaging. Mechanical ventilators, however, are not typically capable of creating step changes in gas concentration at the airway. We designed a ventilator for large animal and human studies that provides mechanical ventilation to a subject inside an MR scanner through 25 feet of small-bore connecting tubing, and tested its capabilities using helium as a surrogate for 17O2. After switching the source gas from oxygen to helium, the 0-90% response time for helium concentration changes at the airway was 2.4 seconds. The capability for creating rapid step changes in gas concentration at the airway in large animal and human studies should facilitate the experimental testing of the delivery 17O2 in brief pulses, and its potential use in imaging CMRO2
Evaluation of African oil palm germplasm for drought tolerance
A field experiment was conducted at ARS Campus, Gangavati, University of Horticultural Sciences, Bagalkot to evaluate the oil palm genotypes for drought tolerance under medium black soils of Tungabhadra Command area of Karnataka. Nine oil palm genotypes were collected from Zambia and Tanzania for drought tolerance studies under rainfed conditions. The genotype ZS-3 recorded significantly higher fresh fruit bunch (FFB) yield 7.0 t ha-1 over Z-6, ZS-8, ZS-8, ZS-9, TS-5 and TS-7. Number of bunches were significantly higher in the genotypes ZS-3 (4.4) followed by ZS-1 (4.1) and ZS-9 (4.0). Bunch weight was significantly higher in the genotype ZS-3 (11.2 kg bunch-1) followed by ZS-5 (10.8 kg bunch-1) and ZS-6 (9.4 kg bunch-1). The number of fruits per bunch was significantly higher in the genotype ZS-8 (3031) over all other genotypes. The number of male inflorescence was lower with the genotype ZS-5 and TS-5 (7.8 and 8.0 respectively). The number of female inflorescence was higher with the genotypes ZS-3 and TS-5 (7.0 and 7.0, respectively). Per cent sex ratio was higher with the genotype TS-5 and ZS-5 (46.2 and 44.8, respectively). The genotype ZS-1 and ZS-5 recorded higher annual leaf production of 21.4 and 20.3, respectively. The genotype ZS-1 recorded significantly lower number of leaf scorched per palm of 2.2 over other genotypes but it was on par with genotype ZS-3 (3.6). The data on various physiological and biochemical parameters revealed that the genotype ZS-1 and ZS-3 recorded higher relative water content, lower electrolyte leaching and significantly lower peroxidase activity indicating relatively more stress tolerant than other tested genotypes
Virus shapes and buckling transitions in spherical shells
We show that the icosahedral packings of protein capsomeres proposed by
Caspar and Klug for spherical viruses become unstable to faceting for
sufficiently large virus size, in analogy with the buckling instability of
disclinations in two-dimensional crystals. Our model, based on the nonlinear
physics of thin elastic shells, produces excellent one parameter fits in real
space to the full three-dimensional shape of large spherical viruses. The
faceted shape depends only on the dimensionless Foppl-von Karman number
\gamma=YR^2/\kappa, where Y is the two-dimensional Young's modulus of the
protein shell, \kappa is its bending rigidity and R is the mean virus radius.
The shape can be parameterized more quantitatively in terms of a spherical
harmonic expansion. We also investigate elastic shell theory for extremely
large \gamma, 10^3 < \gamma < 10^8, and find results applicable to icosahedral
shapes of large vesicles studied with freeze fracture and electron microscopy.Comment: 11 pages, 12 figure
Pre-main-sequence Lithium Depletion
In this review I briefly discuss the theory of pre-main-sequence (PMS) Li
depletion in low-mass (0.075<M<1.2 Msun) stars and highlight those uncertain
parameters which lead to substantial differences in model predictions. I then
summarise observations of PMS stars in very young open clusters, clusters that
have just reached the ZAMS and briefly highlight recent developments in the
observation of Li in very low-mass PMS stars.Comment: 8 pages, invited review at "Chemical abundances and mixing in stars
in the Milky Way and its satellites", eds. L. Pasquini, S. Randich. ESO
Astrophysics Symposium (Springer-Verlag
Real-space local polynomial basis for solid-state electronic-structure calculations: A finite-element approach
We present an approach to solid-state electronic-structure calculations based
on the finite-element method. In this method, the basis functions are strictly
local, piecewise polynomials. Because the basis is composed of polynomials, the
method is completely general and its convergence can be controlled
systematically. Because the basis functions are strictly local in real space,
the method allows for variable resolution in real space; produces sparse,
structured matrices, enabling the effective use of iterative solution methods;
and is well suited to parallel implementation. The method thus combines the
significant advantages of both real-space-grid and basis-oriented approaches
and so promises to be particularly well suited for large, accurate ab initio
calculations. We develop the theory of our approach in detail, discuss
advantages and disadvantages, and report initial results, including the first
fully three-dimensional electronic band structures calculated by the method.Comment: replacement: single spaced, included figures, added journal referenc
B-cell activating factor (BAFF) plasma level at the time of chronic GvHD diagnosis is a potential predictor of non-relapse mortality
Biological markers for risk stratification of chronic GvHD (cGvHD) could improve the care of patients undergoing allogeneic hematopoietic stem cell transplantation. Increased plasma levels of B-cell activating factor (BAFF), chemokine (C-X-C motif) ligand 9 (CXCL9) and elafin have been associated with the diagnosis, but not with outcome in patients with cGvHD. We evaluated the association between levels of these soluble proteins, measured by ELISA at the time of cGvHD diagnosis and before the initiation of therapy, with non-relapse-mortality (NRM). Based on the log-transformed values, factor levels were divided into tertiles defined respectively as low, intermediate, and high levels. On univariable analysis, BAFF levels were significantly associated with NRM, whereas CXCL9 and elafin levels were not. Both low (⩽2.3 ng/mL, hazard ratio (HR)=5.8, P=0.03) and high (>5.7 ng/mL, HR=5.4, P=0.03) BAFF levels were associated with a significantly higher NRM compared with intermediate BAFF level. The significant effect of high or low BAFF levels persisted in multivariable analysis. A subset of cGvHD patients had persistently low BAFF levels. In conclusion, our data show that BAFF levels at the time of cGvHD diagnosis are associated with NRM, and also are potentially useful for risk stratification. These results warrant confirmation in larger studies
Population Dynamics and Non-Hermitian Localization
We review localization with non-Hermitian time evolution as applied to simple
models of population biology with spatially varying growth profiles and
convection. Convection leads to a constant imaginary vector potential in the
Schroedinger-like operator which appears in linearized growth models. We
illustrate the basic ideas by reviewing how convection affects the evolution of
a population influenced by a simple square well growth profile. Results from
discrete lattice growth models in both one and two dimensions are presented. A
set of similarity transformations which lead to exact results for the spectrum
and winding numbers of eigenfunctions for random growth rates in one dimension
is described in detail. We discuss the influence of boundary conditions, and
argue that periodic boundary conditions lead to results which are in fact
typical of a broad class of growth problems with convection.Comment: 19 pages, 11 figure
Scintillation Counters for the D0 Muon Upgrade
We present the results of an upgrade to the D0 muon system. Scintillating
counters have been added to the existing central D0 muon system to provide
rejection for cosmic ray muons and out-of-time background, and to provide
additional fast timing information for muons in an upgraded Tevatron.
Performance and results from the 1994-1996 Tevatron run are presented.Comment: 30 pages, 25 postscript figure
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