14 research outputs found
Clinical and familial correlates of tardive dyskinesia in India and Israel
Background: Antipsychotic drugs are widely used for the treatment of
psychosis, especially schizophrenia. Their long-term use can result at
times in serious side-effects such as Tardive Dyskinesia (TD). Since
over 80% of schizophrenia sufferers (lifetime prevalence 1%) receive
long-term antipsychotic drug treatment, the extent of the problem is
potentially large. Increasing age is the most consistently demonstrated
risk factor for TD. Aims: To assess effect of different clinical
factors and demographic variables in India and Israel and sib pair
concordance of Tardive Dyskinesia (TD) in India. Settings and Design:
The study was conducted simultaneously among Indian and Israeli
subjects: ascertainment was family-based in India and hospital-based in
Israel. Methods and Material: In India the instruments used were:
Diagnostic Interview for Genetic Studies (DIGS), Positive and Negative
Syndrome Scale (PANSS), Abnormal Involuntary Movement Scale (AIMS), and
Simpson Angus Scale (SAS). The last three instruments were also used in
Israel. Statistical Analysis: Regression analysis and Pearson's
correlation. Results and Conclusions: TD symptoms were present in 40.4%
of 151 Israeli subjects and 28.7% of 334 Indian subjects. While age at
onset and total scores on PANSS were significant predictors of TD in
both the samples, lower scores on the Global Assessment of Functioning
Scale (GAF), diagnostic sub-group and male gender were significant
predictors among Indians. There was no concordance of TD symptoms among
33 affected sib-pairs from India
PTF10fqs: A Luminous Red Nova in the Spiral Galaxy Messier 99
The Palomar Transient Factory (PTF) is systematically charting the optical
transient and variable sky. A primary science driver of PTF is building a
complete inventory of transients in the local Universe (distance less than 200
Mpc). Here, we report the discovery of PTF10fqs, a transient in the luminosity
"gap" between novae and supernovae. Located on a spiral arm of Messier 99, PTF
10fqs has a peak luminosity of Mr = -12.3, red color (g-r = 1.0) and is slowly
evolving (decayed by 1 mag in 68 days). It has a spectrum dominated by
intermediate-width H (930 km/s) and narrow calcium emission lines. The
explosion signature (the light curve and spectra) is overall similar to thatof
M85OT2006-1, SN2008S, and NGC300OT. The origin of these events is shrouded in
mystery and controversy (and in some cases, in dust). PTF10fqs shows some
evidence of a broad feature (around 8600A) that may suggest very large
velocities (10,000 km/s) in this explosion. Ongoing surveys can be expected to
find a few such events per year. Sensitive spectroscopy, infrared monitoring
and statistics (e.g. disk versus bulge) will eventually make it possible for
astronomers to unravel the nature of these mysterious explosions.Comment: 12 pages, 12 figures, Replaced with published versio
PTF10iya: A short-lived, luminous flare from the nuclear region of a star-forming galaxy
We present the discovery and characterisation of PTF10iya, a short-lived (dt
~ 10 d, with an optical decay rate of ~ 0.3 mag per d), luminous (M_g ~ -21
mag) transient source found by the Palomar Transient Factory. The
ultraviolet/optical spectral energy distribution is reasonably well fit by a
blackbody with T ~ 1-2 x 10^4 K and peak bolometric luminosity L_BB ~ 1-5 x
10^44 erg per s (depending on the details of the extinction correction). A
comparable amount of energy is radiated in the X-ray band that appears to
result from a distinct physical process. The location of PTF10iya is consistent
with the nucleus of a star-forming galaxy (z = 0.22405 +/- 0.00006) to within
350 mas (99.7 per cent confidence radius), or a projected distance of less than
1.2 kpc. At first glance, these properties appear reminiscent of the
characteristic "big blue bump" seen in the near-ultraviolet spectra of many
active galactic nuclei (AGNs). However, emission-line diagnostics of the host
galaxy, along with a historical light curve extending back to 2007, show no
evidence for AGN-like activity. We therefore consider whether the tidal
disruption of a star by an otherwise quiescent supermassive black hole may
account for our observations. Though with limited temporal information,
PTF10iya appears broadly consistent with the predictions for the early
"super-Eddington" phase of a solar-type star disrupted by a ~ 10^7 M_sun black
hole. Regardless of the precise physical origin of the accreting material, the
large luminosity and short duration suggest that otherwise quiescent galaxies
can transition extremely rapidly to radiate near the Eddington limit; many such
outbursts may have been missed by previous surveys lacking sufficient cadence.Comment: 18 pages, 8 figures; revised following referee's comment
Localizing FRBs through VLBI with the Algonquin Radio Observatory 10 m Telescope
The Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB experiment has detected thousands of fast radio bursts (FRBs) due to its sensitivity and wide field of view; however, its low angular resolution prevents it from localizing events to their host galaxies. Very long baseline interferometry (VLBI), triggered by FRB detections from CHIME/FRB will solve the challenge of localization for non-repeating events. Using a refurbished 10 m radio dish at the Algonquin Radio Observatory located in Ontario Canada, we developed a testbed for a VLBI experiment with a theoretical λ/D ≲ 30 mas. We provide an overview of the 10 m system and describe its refurbishment, the data acquisition, and a procedure for fringe fitting that simultaneously estimates the geometric delay used for localization and the dispersive delay from the ionosphere. Using single pulses from the Crab pulsar, we validate the system and localization procedure, and analyze the clock stability between sites, which is critical for coherently delay referencing an FRB event. We find a localization of ∼200 mas is possible with the performance of the current system (single-baseline). Furthermore, for sources with insufficient signal or restricted wideband to simultaneously measure both geometric and ionospheric delays, we show that the differential ionospheric contribution between the two sites must be measured to a precision of 1 × 10-8 pc cm-3 to provide a reasonable localization from a detection in the 400-800 MHz band. Finally we show detection of an FRB observed simultaneously in the CHIME and the Algonquin 10 m telescope, the first non-repeating FRB in this long baseline. This project serves as a testbed for the forthcoming CHIME/FRB Outriggers project
Three New Eclipsing White-dwarf - M-dwarf Binaries Discovered in a Search for Transiting Planets Around M-dwarfs
We present three new eclipsing white-dwarf / M-dwarf binary systems
discovered during a search for transiting planets around M-dwarfs. Unlike most
known eclipsing systems of this type, the optical and infrared emission is
dominated by the M-dwarf components, and the systems have optical colors and
discovery light curves consistent with being Jupiter-radius transiting planets
around early M-dwarfs. We detail the PTF/M-dwarf transiting planet survey, part
of the Palomar Transient Factory (PTF). We present a Graphics Processing Unit
(GPU)-based box-least-squares search for transits that runs approximately 8X
faster than similar algorithms implemented on general purpose systems. For the
discovered systems, we decompose low-resolution spectra of the systems into
white-dwarf and M-dwarf components, and use radial velocity measurements and
cooling models to estimate masses and radii for the white dwarfs. The systems
are compact, with periods between 0.35 and 0.45 days and semimajor axes of
approximately 2 solar radii (0.01 AU). We use the Robo-AO laser guide star
adaptive optics system to tentatively identify one of the objects as a triple
system. We also use high-cadence photometry to put an upper limit on the white
dwarf radius of 0.025 solar radii (95% confidence) in one of the systems. We
estimate that 0.08% (90% confidence) of M-dwarfs are in these short-period,
post-common-envelope white-dwarf / M-dwarf binaries where the optical light is
dominated by the M-dwarf. Similar eclipsing binary systems can have arbitrarily
small eclipse depths in red bands and generate plausible small-planet-transit
light curves. As such, these systems are a source of false positives for
M-dwarf transiting planet searches. We present several ways to rapidly
distinguish these binaries from transiting planet systems.Comment: 14 pages, 14 figures, submitted to Ap
Sub-second periodicity in a fast radio burst
Fast radio bursts (FRBs) are millisecond-duration flashes of radio waves that
are visible at distances of billions of light-years. The nature of their
progenitors and their emission mechanism remain open astrophysical questions.
Here we report the detection of the multi-component FRB 20191221A and the
identification of a periodic separation of 216.8(1) ms between its components
with a significance of 6.5 sigmas. The long (~3 s) duration and nine or more
components forming the pulse profile make this source an outlier in the FRB
population. Such short periodicity provides strong evidence for a neutron-star
origin of the event. Moreover, our detection favours emission arising from the
neutron-star magnetosphere, as opposed to emission regions located further away
from the star, as predicted by some models.Comment: Updated to conform to the accepted versio
Effect of nutraceutical and psychological interventions on cognitive functions of healthy human subjects
95-102Present study aims to evaluate the effects
of nutraceutical and psychological interventions individually and in
combination, on various cognitive functions of healthy human subjects. Twenty four healthy subjects were
recruited and subdivided into three intervention groups, i.e. nutraceutical,
psychological and combined. Pre- (base
line) &
post-intervention performance levels of all the subjects were established for
each cognitive function using neuropsychological tests. These were further
compared to understand the effect of interventions on the cognitive functions.
A polyherbal liquid formulation<span style="mso-bidi-font-weight:bold;
mso-bidi-font-style:italic"> was administered as Nutraceutical
Intervention. Twelve sessions of Cognitive Behaviour Therapy were given as
Psychological Intervention. Combined intervention consisted of Nutraceutical
& Psychological Interventions together. All the interventions were
administered for a period of 3 months each. Results of the study indicate significant
improvement in overall memory and attention in all the intervention groups.
Immediate memory was also found to be improved significantly in psychological
and combined intervention group<span style="mso-bidi-font-weight:
bold" lang="EN-GB">s<span style="mso-ansi-language:EN-US;mso-bidi-font-weight:
bold" lang="EN-US">. However individual pre and post analysis indicated improvement in
immediate memory in most of the subjects in all the intervention groups Combined
intervention has shown significant improvement in all the cognitive functions except
in cognitive processing speed, planning and organizing abilities. The findings of present study, thus, indicate that the nutraceutical
and psychological interventions
(used in this study) are likely to have positive influence on the cognitive
functions of healthy human subjects. However, better results were obtained when
used in combination.
</span
Original Article - Clinical and familial correlates of tardive dyskinesia in India and Israel
Background: Antipsychotic drugs are widely used for the treatment of psychosis, especially schizophrenia. Their long-term use can result at times in serious side-effects such as Tardive Dyskinesia (TD). Since over 80% of schizophrenia sufferers (lifetime prevalence 1%) receive long-term antipsychotic drug treatment, the extent of the problem is potentially large. Increasing age is the most consistently demonstrated risk factor for TD. Aims: To assess effect of different clinical factors and demographic variables in India and Israel and sib pair concordance of Tardive Dyskinesia (TD) in India. Settings and Design: The study was conducted simultaneously among Indian and Israeli subjects: ascertainment was family-based in India and hospital-based in Israel. Methods and Material: In India the instruments used were: Diagnostic Interview for Genetic Studies (DIGS), Positive and Negative Syndrome Scale (PANSS), Abnormal Involuntary Movement Scale (AIMS), and Simpson Angus Scale (SAS). The last three instruments were also used in Israel. Statistical Analysis: Regression analysis and Pearson’s correlation. Results and Conclusions: TD symptoms were present in 40.4% of 151 Israeli subjects and 28.7% of 334 Indian subjects. While age at onset and total scores on PANSS were significant predictors of TD in both the samples, lower scores on the Global Assessment of Functioning Scale (GAF), diagnostic sub-group and male gender were significant predictors among Indians. There was no concordance of TD symptoms among 33 affected sib-pairs from India
Genetic susceptibility to Tardive Dyskinesia in chronic schizophrenia subjects: I. Association of CYP1A2 gene polymorphism
Understanding the pharmacogenetic basis of developing iatrogenic disorders such as Tardive Dyskinesia (TD) has significant clinical implications. CYP1A2, an inducible gene of the cytochrome P450 family of genes, has been suggested to contribute to the metabolism of typical antipsychotics in subjects with schizophrenia on long-term treatment, and has been considered as a potential candidate gene for development of TD. In this study, we have investigated the significance of CYP1A2 gene polymorphisms in TD susceptibility among chronic schizophrenia sufferers (n=335) from north India. TD was diagnosed in ~29% (96/335) of these subjects. Of the 96 TD positives, 28 had been treated with typical antipsychotics alone, 23 with atypical antipsychotics alone and 45 patients had received both classes of drugs during the course of their illness. Out of the six SNPs tested, CYP1A2*2 *4 *5 *6 were found to be monomorphic in our population. CYP1A2*1C and CYP1A2*1F were polymorphic and were analyzed in the study sample. Since these two allelic variants lead to lesser inducibility among smokers, the smoking status of TD patients was also considered for all subsequent analysis. We observed increased severity of TD among TD-Y smokers, who were carriers of CYP1A2*1C (G>A) variant allele and had received only typical antipsychotic drugs (F(1,8)=9.203, P=0.016). No significant association of CYP1A*21F with TD was observed irrespective of the class of drug they received or their smoking status. However, we found a significant association of CYP1A2*1F with schizophrenia (χ2=6.572, df=2, P=0.037)