656 research outputs found
Infections of the nervous system in India - a review
This article does not have an abstract
Unusual degenerative and environmental diseases seen in India
This article does not have an abstract
Strategic Minerals of India
The state of disequilibrium in the country's mineral economy may not be harmful in time of international peace, but is a source of double danger to national security in a war emergency, when imports of essential commodities, e.g., petroleum may be jeopardised and the off-take of credit earning exports may be stopped. A healthy economy can be achieved by balancing as near as possible, the surpluses against deficits through building up civilian industrial power of production of substitute for some deficient and sub-marginal commodities and stockpiling of others
The properties of some substitute bearing alloys
A bearing is a means for supporting a load between rela-tively moving surfaces with as little friction as possible .' The plain bearings, used in the automobile , aircraft and other engineering industries, consist of
two surfaces, the shaft and the hearing, generally
separated by a film of lubricant. The so-called bear- ing alloys utilised for the purpose have to satisfy
some primary requirements such as suitable chemical
make up giving rise to a hard constituent embedded in
a soft matrix , and a certain range of physical
( melting point , density, thermal conductivity, etc.)
and mechanical (hardness , modulus of elasticity,
tensile strength, impact resistance and age-hardening characteristics) properties. Besides these, certain service properties such as wear, seizure-resistance , conformability , embeddability corrosion-resistance,
etc. are also to be complied with
Quark Confinement and Dual Representation in 2+1 Dimensional Pure Yang-Mills Theory
We study the quark confinement problem in 2+1 dimensional pure Yang-Mills
theory using euclidean instanton methods. The instantons are regularized and
dressed Wu-Yang monopoles. The dressing of a monopole is due to the mean field
of the rest of the monopoles. We argue that such configurations are stable to
small perturbations unlike the case of singular, undressed monopoles. Using
exact non-perturbative results for the 3-dim. Coulomb gas, where Debye
screening holds for arbitrarily low temperatures, we show in a self-consistent
way that a mass gap is dynamically generated in the gauge theory. The mass gap
also determines the size of the monopoles. In a sense the pure Yang-Mills
theory generates a dynamical Higgs effect. We also identify the disorder
operator of the model in terms of the Sine-Gordon field of the Coulomb gas.Comment: 26 pages, RevTex, Title changed, a new section added, the discussion
on stability of dressed monopole expanded. Version to appear in Physical
Review
Acute effects of sex steroids on visual processing in male goldfish
Elevations of sex steroids induced by social cues can rapidly modulate social behavior, but we know little about where they act within the nervous system to produce such effects. In male goldfish, testosterone (T) rapidly increases approach responses to the visual cues of females through its conversion to estradiol. Because aromatase is expressed in the retina, we tested if T can acutely influence retina responses to visual stimuli, and investigated the receptor mechanisms that may mediate such effects. Specifically, we measured FOS protein immunoreactivity to determine if T affects cellular responses to visual stimuli that include females, and used electrophysiology to investigate whether T can generally affect light sensitivity. We found that T acutely increased FOS responses to the simultaneous onset of light and the presence of female visual stimuli, both of which would normally be associated with early morning spawning, and increased electrophysiological responses to low intensity light pulses. Both effects were blocked by an estrogen receptor beta (ERβ) antagonist, indicating that T is likely being converted to estradiol (E2) and acting through an ERβ mediated mechanism to acutely modulate visual processing. Changes in sensory processing could subsequently influence approach behavior to increase reproductive success in competitive mating environments
Phase structure of matrix quantum mechanics at finite temperature
We study matrix quantum mechanics at finite temperature by Monte Carlo
simulation. The model is obtained by dimensionally reducing 10d U(N) pure
Yang-Mills theory to 1d. Following Aharony et al., one can view the same model
as describing the high temperature regime of (1+1)d U(N) super Yang-Mills
theory on a circle. In this interpretation an analog of the deconfinement
transition was conjectured to be a continuation of the black-hole/black-string
transition in the dual gravity theory. Our detailed analysis in the critical
regime up to N=32 suggests the existence of the non-uniform phase, in which the
eigenvalue distribution of the holonomy matrix is non-uniform but gapless. The
transition to the gapped phase is of second order. The internal energy is
constant (giving the ground state energy) in the uniform phase, and rises
quadratically in the non-uniform phase, which implies that the transition
between these two phases is of third order.Comment: 17 pages, 9 figures, (v2) refined arguments in section 3 ; reference
adde
Pure Cerebellar Ataxia with Homozygous Mutations in the PNPLA6 Gene
Autosomal-recessive cerebellar ataxias (ARCA) are clinically and genetically heterogeneous conditions primarily affecting the cerebellum. Mutations in the PNPLA6 gene have been identified as the cause of hereditary spastic paraplegia and complex forms of ataxia associated with retinal and endocrine manifestations in a field where the genotype-phenotype correlations are rapidly expanding. We identified two cousins from a consanguineous family belonging to a large Zoroastrian (Parsi) family residing in Mumbai, India, who presented with pure cerebellar ataxia without chorioretinal dystrophy or hypogonadotropic hypogonadism. We used a combined approach of clinical characterisation, homozygosity mapping, whole-exome and Sanger sequencing to identify the genetic defect in this family. The phenotype in the family was pure cerebellar ataxia. Homozygosity mapping revealed one large region of shared homozygosity at chromosome 19p13 between affected individuals. Within this region, whole-exome sequencing of the index case identified two novel homozygous missense variants in the PNPLA6 gene at c.3847G>A (p.V1283M) and c.3929A>T (p.D1310V) in exon 32. Both segregated perfectly with the disease in this large family, with only the two affected cousins being homozygous. We identified for the first time PNPLA6 mutations associated with pure cerebellar ataxia in a large autosomal-recessive Parsi kindred. Previous mutations in this gene have been associated with a more complex phenotype but the results here suggest an extension of the associated disease spectrum
Universal Cellular Automata and Class 4
Wolfram has provided a qualitative classification of cellular automata(CA)
rules according to which, there exits a class of CA rules (called Class 4)
which exhibit complex pattern formation and long-lived dynamical activity (long
transients). These properties of Class 4 CA's has led to the conjecture that
Class 4 rules are Universal Turing machines i.e. they are bases for
computational universality. We describe an embedding of a ``small'' universal
Turing machine due to Minsky, into a cellular automaton rule-table. This
produces a collection of cellular automata, all of which are
computationally universal. However, we observe that these rules are distributed
amongst the various Wolfram classes. More precisely, we show that the
identification of the Wolfram class depends crucially on the set of initial
conditions used to simulate the given CA. This work, among others, indicates
that a description of complex systems and information dynamics may need a new
framework for non-equilibrium statistical mechanics.Comment: Latex, 10 pages, 5 figures uuencode
Rolling tachyon solution of two-dimensional string theory
We consider a classical (string) field theory of matrix model which was
developed earlier in hep-th/9207011 and subsequent papers. This is a
noncommutative field theory where the noncommutativity parameter is the string
coupling . We construct a classical solution of this field theory and show
that it describes the complete time history of the recently found rolling
tachyon on an unstable D0 brane.Comment: 19 pages, 2 figures, minor changes in text and additional references,
correction of decay time (version to appear in JHEP.
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