516 research outputs found
Utilization of trawl bycatch in Gujarat (India)
Bycatch from trawlers forms a signifi cant quantity of the total marine fi sh landings along the northwest coast of India, particularly in the state of Gujarat, which contributes about 23 percent of the total marine fi sh landings in the country. This paper discusses the composition of this bycatch, its signifi cance in terms of nutritional value, its present utilization pattern and the scope for improvement
Posttransplant Thrombopoiesis Predicts Survival in Patients Undergoing Autologous Hematopoietic Progenitor Cell Transplantation
AbstractThe frequency and clinical significance of secondary thrombocytopenia following initial engraftment in autologous hematopoietic progenitor cell transplantation (HPCT) is unknown. An institutional review board approved retrospective study of thrombopoiesis was performed in 359 patients transplanted with autologous blood (97%) or marrow (3%) who achieved platelet engraftment to >50,000/μL. Idiopathic secondary posttransplant thrombocytopenia (ISPT) was defined as >50% decline in blood platelets to <100,000/μL in the absence of relapse or sepsis. ISPT occurred at a median of day +35 posttransplant in 17% of patients. Patients with ISPT had similar initial platelet engraftment (median 17 days) versus non-ISPT patients (18 days; P = NS) and recovered platelet counts (median 123,00 K/μL) by day 110 posttransplant. Four factors were independently associated with post-transplant death in a multivariate model: disease status at transplant; the number of prior chemotherapy regimens, failure to achieve a platelet count of >150,000/μL posttransplant, and the occurrence of ISPT. A prognostic score was developed based upon the occurrence of ISPT and posttransplant platelet counts of <150,000/μL. Survival of patients with both factors (n = 25) was poor (15% alive at 5 years); patients with 1 factor (n = 145) had 49% 5-year survival; patients with 0 factors (n = 189) had 72% 5-year survival. Patients who failed to achieve a platelet count of >150,000/μL received significantly fewer CD34+ cells/kg (P < .001), whereas patients with ISPT received fewer CD34+CD38− cells/kg (P = .0006). The kinetics of posttransplant thrombopoiesis is an independent prognostic factor for long-term survival following autologous HPC. ISPT and lower initial posttransplant platelet counts reflect poor engraftment with long-term and short-term repopulating CD34+ hematopoietic stem cells, respectively, and are associated with an increased risk of death from disease relapse
Overview of the spectrometer optical fiber feed for the Habitable-zone Planet Finder
The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber fed
precision radial velocity (RV) spectrograph working in the Near Infrared (NIR):
810 - 1280 nm . In this paper we present an overview of the preparation of the
optical fibers for HPF. The entire fiber train from the telescope focus down to
the cryostat is detailed. We also discuss the fiber polishing, splicing and its
integration into the instrument using a fused silica puck. HPF was designed to
be able to operate in two modes, High Resolution (HR- the only mode mode
currently commissioned) and High Efficiency (HE). We discuss these fiber heads
and the procedure we adopted to attach the slit on to the HR fibers.Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation,
Austin, Texas, USA. 18 pages, 25 figures, and 2 table
Improving the Thermal Stability of a CCD Through Clocking
Modern precise radial velocity spectrometers are designed to infer the
existence of planets orbiting other stars by measuring few-nm shifts in the
positions of stellar spectral lines recorded at high spectral resolution on a
large-area digital detector. While the spectrometer may be highly stabilized in
terms of temperature, the detector itself may undergo changes in temperature
during readout that are an order of magnitude or more larger than the other
opto-mechanical components within the instrument. These variations in detector
temperature can translate directly into systematic measurement errors. We
explore a technique for reducing the amplitude of CCD temperature variations by
shuffling charge within a pixel in the parallel direction during integration.
We find that this "dither clocking" mode greatly reduces temperature variations
in the CCDs being tested for the NEID spectrometer. We investigate several
potential negative effects this clocking scheme could have on the underlying
spectral data.Comment: Submitted to JATIS, special issue from the ISPA 2018 conference. 11
pages, 9 figure
TIRSPEC : TIFR Near Infrared Spectrometer and Imager
We describe the TIFR Near Infrared Spectrometer and Imager (TIRSPEC) designed
and built in collaboration with M/s. Mauna Kea Infrared LLC, Hawaii, USA, now
in operation on the side port of the 2-m Himalayan Chandra Telescope (HCT),
Hanle (Ladakh), India at an altitude of 4500 meters above mean sea level. The
TIRSPEC provides for various modes of operation which include photometry with
broad and narrow band filters, spectrometry in single order mode with long
slits of 300" length and different widths, with order sorter filters in the Y,
J, H and K bands and a grism as the dispersing element as well as a cross
dispersed mode to give a coverage of 1.0 to 2.5 microns at a resolving power R
of ~1200. The TIRSPEC uses a Teledyne 1024 x 1024 pixel Hawaii-1 PACE array
detector with a cutoff wavelength of 2.5 microns and on HCT, provides a field
of view of 307" x 307" with a plate scale of 0.3"/pixel. The TIRSPEC was
successfully commissioned in June 2013 and the subsequent characterization and
astronomical observations are presented here. The TIRSPEC has been made
available to the worldwide astronomical community for science observations from
May 2014.Comment: 20 pages, 21 figures, 2 tables. Accepted for publication in Journal
of Astronomical Instrumentatio
Developmental Studies on Metallised UDMH and Kerosene Gels
The influence of particulate and hydrocolloid gellants and different surfactants on gellation of metallised stable gels of unsymmetrical dimethyl hydrazine (UDMH) and kerosene containing 30 per cent 15 micron Aluminium was studied. Metallised UDMH and kerosene gels were characterised with respect to pseudoplasticity, thixotropy, consistency and yield stress using Contrave's rheometer. The effect of shear rate and temperature on the viscosity of these gels was determined. Thermal stability, hypergolicity tests and flow rate studies were also conducted. Metallised UDMH and kerosene gels are found to be stable, thixotropic and pseudoplastic and easily flowing like a liquid under shear force
Automated Galaxy Morphology: A Fourier Approach
We use automated surface photometry and pattern classification techniques to
morphologically classify galaxies. The two-dimensional light distribution of a
galaxy is reconstructed using Fourier series fits to azimuthal profiles
computed in concentric elliptical annuli centered on the galaxy. Both the phase
and amplitude of each Fourier component have been studied as a function of
radial bin number for a large collection of galaxy images using principal
component analysis. We find that up to 90 percent of the variance in many of
these Fourier profiles may be characterized in as few as 3 principal components
and their use substantially reduces the dimensionality of the classification
problem. We use supervised learning methods in the form of artificial neural
networks to train galaxy classifiers that detect morphological bars at the
85-90 percent confidence level and can identify the Hubble type with a 1-sigma
scatter of 1.5 steps on the 16-step stage axis of the revised Hubble system.
Finally, we systematically characterize the adverse effects of decreasing
resolution and S/N on the quality of morphological information predicted by
these classifiers.Comment: Accepted to Astrophysical Journal, 43 pages, 12 figure
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