754 research outputs found
Case report of total hip replacement in an amputatee
Total hip replacement (THR) in an ipsilateral neck of femur fracture is an unusual situation. Hip fractures are a common source of morbidity and mortality worldwide. Nevertheless, the discovery and development of hip arthroplasty has improved its prognosis, with a high survival rate and satisfactory functional results. Although total hip replacement has been well described in the literature especially for healthy individuals, we found only few pieces of information about the technical characteristics and results of this procedure in patients with lower extremity amputation. There were few previous case reports in the literature that describe total hip replacement (THR) in above-knee amputees and this was the first case to be done in our institute. We presented a case involving an above knee amputee (AKA) who sustained an ipsilateral neck of femur fracture. Our patient underwent a THR with a satisfactory post-operative outcome. Technical considerations for AKAs undergoing THR also are reviewed in this article
Precision pointing of imaging spacecraft using gyro-based attitude reference with horizon sensor updates
Remote sensing satellites are required to meet stringent pointing and drift rate requirements for imaging operations. For achieving these pointing and stability requirements, continuous and accurate three-axis attitude information is required. Inertial sensors like gyros provide continuous attitude information with better short-term stability and less random errors. However, gyro measurements are affected by drifts. Hence over time, attitudes based on the gyro reference slowly diverge from the true attitudes. On the other hand, line-of-sight (LOS) sensors like horizon sensors provide attitude information with long-term stability. Their measurements however are affected by the presence of random instrumental errors and other systematic errors. The limitations of inertial and line-of-sight sensors are mutually exclusive. Hence, by optimal fusion of attitude information from both these sensors, it is possible to retain the advantages and overcome the limitations of both, thereby providing the precise attitude information required for control. This paper describes an improved earth-pointing scheme by fusion of the three-axis attitude information from gyros and horizon sensor roll and pitch measurements along with yaw updates from the digital sun sensor. A Kalman Filter is used to estimate the three-axis attitude by online estimation and corrections of various errors from the sensor measurements. Variations in orbit rate components are also accounted for using spacecraft position and velocity measurements from the satellite positioning system. Thus precise earth-pointing is achieved
Timing Offset Calibration of CZTI instrument aboard ASTROSAT
The radio as well as the high energy emission mechanism in pulsars is yet not
understood properly. A multi-wavelength study is likely to help in better
understanding of such processes. The first Indian space-based observatory,
ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum
from infra-red (1300 ) to hard X-ray (380 KeV). Cadmium Zinc Telluride
Imager (CZTI), one of the five instruments is a hard X-ray telescope functional
over an energy range of 20-380 KeV. We aim to estimate the timing offset
introduced in the data acquisition pipeline of the instrument, which will help
in time alignment of high energy time series with those from two other
ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and
the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with
nearly aligned radio and hard X-ray pulse profiles. We use simultaneous
observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar
was especially observed using the ORT with almost daily cadence to obtain good
timing solutions. We also supplement the ORT data with archival FERMI data for
estimation of timing noise. The timing offset of ASTROSAT instruments was
estimated from fits to arrival time data at the ASTROSAT and the radio
observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to
be -4716 50 . The corresponding offset with the ORT was -29639
50 . The offsets between the GMRT and Fermi-LAT -5368 56
. (Abridged)Comment: 6 pages, 5 figures, 2 tables, Revised and Updated, accepted for
publication in A&
CdO-based nanostructures as novel CO2 gas sensors
Crystalline Cd(OH)2/CdCO3 nanowires, having lengths in the range from 0.3 up to several
microns and 5–30 nm in diameter, were synthesized by a microwave-assisted wet chemical
route and used as a precursor to obtain CdO nanostructures after a suitable thermal treatment in
air. The morphology and microstructure of the as-synthesized and annealed materials have been
investigated by scanning electron microscopy, transmission electron microscopy, x-ray
diffraction and thermogravimetry–differential scanning calorimetry. The change in morphology
and electrical properties with temperature has revealed a wire-to-rod transformation along with
a decreases of electrical resistance.
Annealed samples were printed on a ceramic substrate with interdigitated contacts to
fabricate resistive solid state sensors. Gas sensing properties were explored by monitoring
CO2 in synthetic air in the concentration range 0.2–5 v/v% (2000–50 000 ppm). The effect of
annealing temperature, working temperature and CO2 concentration on sensing properties
(sensitivity, response/recovery time and stability) were investigated. The results obtained
demonstrate that CdO-based thick films have good potential as novel CO2 sensors for practical
applications
Stomach contents of cetaceans incidentally caught along Mangalore and Chennai coasts of India
Abstract
The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits
Electronic structure of NiS_{1-x}Se_x
We investigate the electronic structure of the metallic NiSSe
system using various electron spectroscopic techniques. The band structure
results do not describe the details of the spectral features in the
experimental spectrum, even for this paramagnetic metallic phase. However, a
parameterized many-body multi-band model is found to be successful in
describing the Ni~2 core level and valence band, within the same model. The
asymmetric line shape as well as the weak intensity feature in the Ni~2 core
level spectrum has been ascribed to extrinsic loss processes in the system. The
presence of satellite features in the valence band spectrum shows the existence
of the lower Hubbard band, deep inside the metallic regime, consistent
with the predictions of the dynamical mean field theory.Comment: To be published in Physical Review B, 18 pages and 5 figure
Electronic structure of NiSSe across the phase transition
We report very highly resolved photoemission spectra of NiS(1-x)Se(x) across
the so-called metal-insulator transition as a function of temperature as well
as composition. The present results convincingly demonstrate that the low
temperature, antiferromagnetic phase is metallic, with a reduced density of
states at E. This decrease is possibly due to the opening of gaps along
specific directions in the Brillouin zone caused by the antiferromagnetic
ordering.Comment: Revtex, 4 pages, 3 postscript figure
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