HI Fluctuations at Large Redshifts: II - the Signal Expected for GMRT

For the GMRT, we calculate the expected signal from redshifted HI emission at two frequency bands centered at 610 and 325 MHz. The study focuses on the visibility-visibility cross-correlations, proposed earlier as the optimal statistical estimator for detecting and analyzing this signal. These correlations directly probe the power spectrum of density fluctuations at the redshift where the radiation originated, and thereby provide a method for studying the large scale structures at large redshifts. We present detailed estimates of the correlations expected between the visibilities measured at different baselines and frequencies. Analytic fitting formulas representing the salient features of the expected signal are also provided. These will be useful in planning observations and deciding an optimal strategy for detecting this signal.Comment: 16 pages including 7 figures, published in JAp

Individual differences in supra-threshold auditory perception - mechanisms and objective correlates

Thesis (Ph.D.)--Boston UniversityTo extract content and meaning from a single source of sound in a quiet background, the auditory system can use a small subset of a very redundant set of spectral and temporal features. In stark contrast, communication in a complex, crowded scene places enormous demands on the auditory system. Spectrotemporal overlap between sounds reduces modulations in the signals at the ears and causes masking, with problems exacerbated by reverberation. Consistent with this idea, many patients seeking audiological treatment seek help precisely because they notice difficulties in environments requiring auditory selective attention. In the laboratory, even listeners with normal hearing thresholds exhibit vast differences in the ability to selectively attend to a target. Understanding the mechanisms causing these supra-threshold differences, the focus of this thesis, may enable research that leads to advances in treating communication disorders that affect an estimated one in five Americans. Converging evidence from human and animal studies points to one potential source of these individual differences: differences in the fidelity with which supra-threshold sound is encoded in the early portions of the auditory pathway. Electrophysiological measures of sound encoding by the auditory brainstem in humans and animals support the idea that the temporal precision of the early auditory neural representation can be poor even when hearing thresholds are normal. Concomitantly, animal studies show that noise exposure and early aging can cause a loss (cochlear neuropathy) of a large percentage of the afferent population of auditory nerve fibers innervating the cochlear hair cells without any significant change in measured audiograms. Using behavioral, otoacoustic and electrophysiological measures in conjunction with computational models of sound processing by the auditory periphery and brainstem, a detailed examination of temporal coding of supra-threshold sound is carried out, focusing on characterizing and understanding individual differences in listeners with normal hearing thresholds and normal cochlear mechanical function. Results support the hypothesis that cochlear neuropathy may reduce encoding precision of supra-threshold sound, and that this manifests as deficits both behaviorally and in subcortical electrophysiological measures in humans. Based on these results, electrophysiological measures are developed that may yield sensitive, fast, objective measures of supra-threshold coding deficits that arise as a result of cochlear neuropathy

A Pilot Study to Evaluate the Effects of Cerebroprotein Hydrolysate on Neurological Outcomes and Hospital Stay in Patients Admitted for Ischemic and Hemorrhagic Stroke

Introduction: Neurological stroke is the most common cause of disability and leaves nearly 65% of survivors with sensory, motor and coordinative disabilities. At present, there are no therapies to prevent long-term neurological deficits after stroke. Many neuroprotective drugs are being tested with the aim to ensure these effects. Preclinical studies have shown a modulatory effect of cerebroprotein hydrolysate on synaptic remodeling and facilitated synaptic transmission. Material and methods: This was a hospital-based, open-label pilot study conducted in a tertiary care hospital of North India. All patients admitted with a diagnosis of stroke both ischemic and hemorrhagic, were included in the study. Patients were randomized into two groups. The test group was given cerebroprotein hydrolysate, along with standard treatment for stroke, whereas the other group was kept on standard treatment for stroke as per the latest guidelines, without cerebroprotein. Results: A total of 50 patients of stroke, admitted in a tertiary care center were included in the study. The mean age of the patients was 65.7 ± 11.86 years. Twenty-six (52%) were males and 24 (48%) were females. Out of the total 50 patients, 23 (46%) had ischemic stroke and 27 (54%) had hemorrhagic stroke. Twenty (40%) had diabetes, 37 (74%) had hypertension, 8 (16%) were known cases of coronary artery disease, 28 (56%) had dyslipidemia, 22 (44%) were smokers, 7 (14%) had a history of ethanol consumption and 13 (26%) were obese. Mean Barthel score at admission was 21.2 ± 11.3 and mean Rankin score at admission was 3.6 ± 1.37. Mean Barthel score at end of treatment was 53.9 ± 28.72 and mean Rankin score at end of treatment was 2.6 ± 1.65. The mean duration of admission was 6.8 ± 3.57 days. Conclusion: The current study highlights the role of cerebroprotein hydrolysate in improving the neurological scores and reducing hospital stay among patients hospitalized with stroke

Study of market potential of plant based medicine A study of Dengue and Malaria

Treatment of illnesses with plants and plant-based concentrates has been a vital piece of the tropical regions. With the progression of innovative work in medication, there has been an expansion in the consideration of plant-based concentrates and side-effects utilized in the treatment of numerous ailments, use of conventional medications for sicknesses are getting incorporated into present-day prescription technique alongside normal medicines. Every year inclusive, the treatment of dengue and Malaria consolidated expenses are around USD 20 Billion every year. This paper centers around the market potential in the plant-based treatment of Dengue and Malaria as the diverse plants utilized in the treatment are broadly well-known and are developed in nations like India, African nations, and Latin America. It additionally tosses light on the recent trends in dengue and Malaria, customary strategies for treatment, and Dengue in the present day

Mental health stigma

Comparing self-reports to administrative records, we find that survey respondents are significantly more likely to under-report mental illnesses compared to other health conditions. This behavior is consistent with the existence of stigma of mental illnesses. We show that stigma can play a role in determining health-seeking behavior

The CMBR ISW and HI 21-cm Cross-correlation Angular Power Spectrum

The late-time growth of large scale structures (LSS) is imprinted in the CMBR anisotropy through the Integrated Sachs Wolfe (ISW) effect. This is perceived to be a very important observational probe of dark energy. Future observations of redshifted 21-cm radiation from the cosmological neutral hydrogen (HI) distribution hold the potential of probing the LSS over a large redshift range. We have investigated the possibility of detecting the ISW through cross-correlations between the CMBR anisotropies and redshifted 21-cm observations. Assuming that the HI traces the dark matter, we find that the ISW-HI cross-correlation angular power spectrum at an angular multipole l is proportional to the dark matter power spectrum evaluated at the comoving wave number l/r, where r is the comoving distance to the redshift from which the HI signal originated. The amplitude of the cross-correlation signal depends on parameters related to the HI distribution and the growth of cosmological perturbations. However the cross-correlation is extremely weak as compared to the CMBR anisotropies and the predicted HI signal. As a consequence the cross-correlation signal is smaller than the cosmic variance, and a statistically significant detection is not very likely.Comment: 13 pages, 4 eps figures, submitte

Initial destination of the disaccommodation step response

AbstractPeak velocity and peak acceleration of disaccommodation step responses remain invariant of response magnitude for a constant starting position and they increase linearly with proximity of starting position. This suggests that disaccommodation response is initiated towards an initial (default) destination and is switched mid-flight to attain the desired final destination. The dioptric location of initial destination was estimated from the x-intercept of regression of peak velocity on response starting position. The x-intercept correlated well with subject’s cycloplegic refractive state and poorly with their dark focus of accommodation. Altering the dark focus by inducing fatigue in the accommodative system did not alter the x-intercept. These observations suggest that cycloplegic refractive state is a good behavioral correlate of initial destination of disaccommodation step responses