1,854 research outputs found
Scanning electron microscopic observations on the third ventricular floor of the rat following cervical sympathectomy
Various investigators have shown that unilateral ganglionectomy or transection
of the internal and external carotid nerves leads to a regenerative response in the ipsilateral superior cervical ganglion and to uninjured mature sympathetic neurons sprouting into bilaterally innervated shared target organs. In this study changes in the supraependymal neuronal network following unilateral and bilateral
cervical sympathectomy on the infundibular floor of the third ventricle were studied by scanning electron microscopy in comparison with normal and sham-operated control animals. After unilateral cervical sympathectomy there was a great increase in the number of varicose nerve fibres on the infundibular floor as compared to the normal and sham-operated control animals. Not only was there an increase in the number of nerve fibres, but also their varicosities were substantially larger than those normally present on the ependymal surface. This study indicates the possible sympathetic projections from the superior cervical
ganglia to the ependymal surface of the third cerebral ventricle
Supersymmetry in Slow Motion
We construct new theories of electroweak symmetry breaking that employ a
combination of supersymmetry and discrete symmetries to stabilize the weak
scale up to and beyond the energies probed by the LHC. These models exhibit
conventional supersymmetric spectra but the fermion-sfermion-gaugino vertices
are absent. This closes many conventional decay channels, thereby allowing
several superpartners to be stable on collider time scales. This opens the door
to the possibility of directly observing R-hadrons and three flavors of
sleptons inside the LHC detectors.Comment: A reference added. The discussion on the Higgs sector expanded. The
version accepted for publication in JHE
Role of various causes of death in diverging life expectancy in Kerala, India
Background: Life expectancy at birth is an indicator of mortality conditions and health conditions. Mortality happens due to many causes. The multiple-decrement life table is used widely in human actuarial literature and provides statistical expressions for mortality in which the cause elimination is used. Cause elimination life tables address the hypothetical question of what a cohort’s mortality experience would be if a particular cause of death were eliminated. The goal of this study is to estimate the potential gain in life expectancy after complete elimination of certain causes of death in Kerala, India for the year 2018.
Methods: The data for the study was taken from annual vital statistic report, Kerala, 2018. Life table method was used for estimating the potential gain in life expectancy after eliminating certain causes of deaths.
Results: The elimination of deaths due to heart diseases, cancer, respiratory diseases, accidents and suicides resulted a gain of 7.18 years, 6.90 years, 8.04 years, 6.72 years and 7.09 years respectively. The results show that in 2018, for Kerala, the highest gain in life expectancy was due to elimination of respiratory diseases, followed by other causes of death. The present study shows that heart diseases and respiratory diseases are the causes which are more affected among Keralites.
Conclusions: Effective intervention needs to be implemented in Kerala so as to reduce the risk of the diseases, which would result in the increase of life expectancy at birth
The GUT Scale and Superpartner Masses from Anomaly Mediated Supersymmetry Breaking
We consider models of anomaly-mediated supersymmetry breaking (AMSB) in which
the grand unification (GUT) scale is determined by the vacuum expectation value
of a chiral superfield. If the anomaly-mediated contributions to the potential
are balanced by gravitational-strength interactions, we find a
model-independent prediction for the GUT scale of order . The GUT threshold also affects superpartner masses, and can easily
give rise to realistic predictions if the GUT gauge group is asymptotically
free. We give an explicit example of a model with these features, in which the
doublet-triplet splitting problem is solved. The resulting superpartner
spectrum is very different from that of previously considered AMSB models, with
gaugino masses typically unifying at the GUT scale.Comment: 17 page
Large Extra Dimensions from a Small Extra Dimension
Models with extra dimensions have changed our understanding of the hierarchy
problem. In general, these models explain the weakness of gravity by diluting
gravity in a large bulk volume, or by localizing the graviton away from the
standard model. In this paper, we show that the warped geometries necessary for
the latter scenario can naturally induce the large volumes necessary for the
former. We present a model in which a large volume is stabilized without
supersymmetry. We comment on the phenomenology of this scenario and
generalizations to additional dimensions.Comment: Some formulae altered, conclusions unchange
Prevalence and Correlates of Functional Limitation Among Elderly in Kerala
Performance of IADL could be closely related to biological variables such as age and sex. Since women outnumbered men among the sample population, it is hopeful to conclude that elderly women can be relished with functional independence, but in the advancement of their age, they have to suffer a lot. The results of the study showed that the extended life year is accompanied by increased demands on health care delivery systems as more part of life may be spent with some functional limitation. The prevalence of physical disability in elderly persons with functional limitation is, therefore, important for policy development in the care of the elderly. The most effective way to reduce the proportion of the population with disabilities is to delay the onset of disabilities. Living independently in familiar surroundings surely promotes a better aging and the development of living environments together with functional ability exert a profound influence on active aging. In Kerala situation, geriatric care should be focused on the necessities of elderly women since they have to live more years with functional limitation and disability than males. The number of people surviving into old age is increasing. The growth of the elderly population is expected to escalate in the coming years with respect to the general population. Longevity of people may result in poor health status, disability and loss of functional health. Information on disability is very important in responding to the care of the elderly
Neutrino Telescopes as a Direct Probe of Supersymmetry Breaking
We consider supersymmetric models where the scale of supersymmetry breaking
lies between 5 GeV and 5 GeV. In this class of
theories, which includes models of gauge mediated supersymmetry breaking, the
lightest supersymmetric particle is the gravitino. The next to lightest
supersymmetric particle is typically a long lived charged slepton with a
lifetime between a microsecond and a second, depending on its mass. Collisions
of high energy neutrinos with nucleons in the earth can result in the
production of a pair of these sleptons. Their very high boost means they
typically decay outside the earth. We investigate the production of these
particles by the diffuse flux of high energy neutrinos, and the potential for
their observation in large ice or water Cerenkov detectors. The relatively
small cross-section for the production of supersymmetric particles is partially
compensated for by the very long range of heavy particles. The signal in the
detector consists of two parallel charged tracks emerging from the earth about
100 meters apart, with very little background. A detailed calculation using the
Waxman-Bahcall limit on the neutrino flux and realistic spectra shows that
km experiments could see as many as 4 events a year. We conclude that
neutrino telescopes will complement collider searches in the determination of
the supersymmetry breaking scale, and may even give the first evidence for
supersymmetry at the weak scale.Comment: 4 pages, 3 figure
Purely Four-dimensional Viable Anomaly Mediation
Anomaly mediation of supersymmetry breaking solves the supersymmetric flavor
problem thanks to its ultraviolet-insensitivity. However, it suffers from two
problems: sleptons have negative masses-squared, and there are likely bulk
moduli that spoil the framework. Here, we present the first fully
ultraviolet-insensitive model of anomaly mediation with positive slepton
masses-squared in a purely four-dimensional framework. Our model is based on
the additional D-term contributions to the sparticle masses, and the conformal
sequestering mechanism.Comment: 7 pages, Uses RevTex4 (included). References modifie
Product Groups, Discrete Symmetries, and Grand Unification
We study grand unified theories based on an SU(5)xSU(5) gauge group in which
the GUT scale, M_{GUT}, is the VEV of an exact or approximate modulus, and in
which fast proton decay is avoided through a combination of a large triplet
mass and small triplet couplings. These features are achieved by discrete
symmetries. In many of our models, M_{GUT} is generated naturally by the
balance of higher dimension terms that lift the GUT modulus potential, and soft
supersymmetry breaking masses. The theories often lead to interesting patterns
of quark and lepton masses. We also discuss some distinctions between grand
unified theories and string unification.Comment: 23 pages; no figures; revtex
Implications on SUSY breaking mediation mechanisms from observing and the muon
We consider and the muon in various SUSY
breaking mediation mechanisms. If the decay is observed
at Tevatron Run II with a branching ratio larger than ,
the noscale supergravity (including the gaugino mediation), the gauge mediation
scenario with small number of messenger fields and low messenger scale, and a
class of anomaly mediation scenarios will be excluded, even if they can
accommodate a large muon . On the other hand, the minimal
supergravity scenario and similar mechanisms derived from string models can
accommodate this observation.Comment: 4 pages, 3 figure
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