8,286 research outputs found
Radion Stabilization by Stringy Effects in General Relativity
We consider the effects of a gas of closed strings (treated quantum
mechanically) on a background where one dimension is compactified on a circle.
After we address the effects of a time dependent background on aspects of the
string spectrum that concern us, we derive the energy-momentum tensor for a
string gas and investigate the resulting space-time dynamics. We show that a
variety of trajectories are possible for the radius of the compactified
dimension, depending on the nature of the string gas, including a demonstration
within the context of General Relativity (i.e. without a dilaton) of a solution
where the radius of the extra dimension oscillates about the self-dual radius,
without invoking matter that violates the various energy conditions. In
particular, we find that in the case where the string gas is in thermal
equilibrium, the radius of the compactified dimension dynamically stabilizes at
the self-dual radius, after which a period of usual Friedmann-Robertson-Walker
cosmology of the three uncompactified dimensions can set in. We show that our
radion stabilization mechanism requires a stringy realization of inflation as
scalar field driven inflation invalidates our mechanism. We also show that our
stabilization mechanism is consistent with observational bounds.Comment: New section on the phenomonological implications of and bound on the
model has been adde
Perturbations in a Bouncing Brane Model
The question of how perturbations evolve through a bounce in the Cyclic and
Ekpyrotic models of the Universe is still a matter of ongoing debate. In this
report we show that the collision between boundary branes is in most cases
singular even in the full 5-D formalism, and that first order perturbation
theory breaks down for at least one perturbation variable. Only in the case
that the boundary branes approach each other with constant velocity shortly
before the bounce, can a consistent, non singular solution be found. It is then
possible to follow the perturbations explicitly until the actual collision. In
this case, we find that if a scale invariant spectrum developed on the hidden
brane, it will get transferred to the visible brane during the bounce.Comment: 15 pages, minor modifications, a few typos correcte
The Cosmology of Massless String Modes
We consider the spacetime dynamics of a gas of closed strings in the context
of General Relativity in a background of arbitrary spatial dimensions. Our
motivation is primarily late time String Gas Cosmology, where such a spacetime
picture has to emerge after the dilaton has stabilized. We find that after
accounting for the thermodynamics of a gas of strings, only string modes which
are massless at the self-dual radius are relevant, and that they lead to a
dynamics which is qualitatively different from that induced by the modes
usually considered in the literature. In the context of an ansatz with three
large spatial dimensions and an arbitrary number of small extra dimensions, we
obtain isotropic stabilization of these extra dimensions at the self-dual
radius. This stabilization occurs for fixed dilaton, and is induced by the
special string states we focus on. The three large dimensions undergo a regular
Friedmann-Robertson-Walker expansion. We also show that this framework for
late-time cosmology is consistent with observational bounds.Comment: 15 pages, no figures, references added (again
AWARENESS, KNOWLEDGE AND ATTITUDE ABOUT DENGUE AMONG SOCIETY
Objective: The survey about dengue was carried out to gather the information about dengue fever, create awareness among the people. To determined the index of knowledge, attitude and awareness among the surveyed population about dengue.
Methods: The questionnaire was prepared under the guidance of a pharmacologist. Pilot study was conducted among ten nos. of the population prior actual study. Questionnaire was revised and finalized according to an input of the pilot study. This questionnaire presented to the hundred peoples of different age group. Method involves face to face interview and seeking answers for different questions. Responses were recorded for further analysis and interpretation. Responses were sorted and analyzed. Different questions were categorized into the domain of awareness, knowledge and attitude. Data was presented in the form of graphs.
Results: Percentage of awareness, knowledge and attitude found to be 59, 44, 52 respectively. It is observed that three parameters are almost in the range of fifty percent. Precautions plays vital role in prevention of Dengue.
Conclusion: it is concluded that there is scope for improvement for creating awareness, knowledge and attitude among the surveyed population as representative of the general population. This may help to overcome the risk of this communicable and deadly disease
Two phase detonation studies
An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant
Direct to consumer advertising via the Internet, a study of hip resurfacing
With increased use of the internet for health information and direct to consumer advertising from medical companies, there is a concern about the quality of the information available for patients. The aim of this study was to examine the quality of health information on the internet for hip resurfacing. An assessment tool was designed to measure quality of information. Websites were measured on credibility of source; usability; currentness of the information; content relevance; content accuracy/completeness and disclosure/bias. Each website assessed was given a total score, based on number of scores achieved from the above categories websites were further analysed on author, geographical origin and possession of an independent credibility check. There was positive correlation between the overall score for the website and the score of each website in each assessment category. Websites by implant companies, doctors and hospitals scored poorly. Websites with an independent credibility check such as Health on the Net (HoN) scored twice the total scores of websites without. Like other internet health websites, the quality of information on hip resurfacing websites is variable. This study highlights methods by which to assess the quality of health information on the internet and advocates that patients should look for a statement of an "independent credibility check" when searching for information on hip resurfacing
Evolution of the Kondo resonance feature and its relationship to spin-orbit coupling across the quantum critical point in Ce2Rh{1-x}CoxSi3
We investigate the evolution of the electronic structure of Ce2Rh{1-x}CoxSi3
as a function of x employing high resolution photoemission spectroscopy. Co
substitution at the Rh sites in antiferromagnetic Ce2RhSi3 leads to a
transition from an antiferromagnetic system to a Kondo system, Ce2CoSi3 via the
Quantum Critical Point (QCP). High resolution photoemission spectra reveal
distinct signature of the Kondo resonance feature (KRF) and its spin orbit
split component (SOC) in the whole composition range indicating finite Kondo
temperature scale at the quantum critical point. We observe that the intensity
ratio of the Kondo resonance feature and its spin orbit split component,
KRF/SOC gradually increases with the decrease in temperature in the strong
hybridization limit. The scenario gets reversed if the Kondo temperature
becomes lower than the magnetic ordering temperature. While finite Kondo
temperature within the magnetically ordered phase indicates applicability of
the spin density wave picture at the approach to QCP, the dominant temperature
dependence of the spin-orbit coupled feature suggests importance of spin-orbit
interactions in this regime.Comment: 6 figure
HOMOGENEOUS MULTI-INTERFACE MOBILE NODE SUPPORT IN NS2
NS2 is a widely used, open source tool for network simulation. A Mobile Node (MN) in NS2 by default provides only a single Wi-Fi interface. It makes difficult for users to simulate the scenario where a mobile node is connected to multiple networks through different interfaces at the same time. Some projects have been done to implement multiple Wi-Fi interfaces but according to our view they have some limitations. This paper presents the implementation of mobile nodes in NS2 with multiple Wi-Fi interfaces and multiple WiMAX interfaces trying to overcome those limitations
Bilateral reversed palmaris longus muscle with trifid insertion, a rare variation
Normally the palmaris longus muscle originates from the medial epicondyle of the humerus from common flexor origin. In the middle of the forearm, the muscle belly forms a tendon which is inserted into the flexor retinaculum and the palmar aponeurosis. In our study after dissection of both forearms of a 45-year-old male cadaver we found a reversed palmaris longus muscle. This means that the palmaris longus muscle was tendinous in its proximal part and muscular in its distal part. The fleshy belly of muscle was passing over flexor retinaculum, was ensheathed by separate fascia. The muscle belly was spreading on both the sides of each palm for insertion which was trifid, that is centrally into palmar aponeurosis, laterally continuous with the fascia covering the thenar muscles and medially with Abductor digit minimi. It was having tendinous interconnection with the muscle mass of both the sides. Bilateral reversed palmaris longus muscle mentioned in the literature, was a surgical finding in a patient who suffered from edema and pain in the wrist. The overuse of the reversed palmaris longus muscle can lead to the muscle’s local hypertrophy. As per the literature a reversed palmaris longus muscle may cause a compartment syndrome with pain and edema in the wrist area, the carpal tunnel syndrome and Guyon’s syndrome. The variation is also useful to the hand surgeon, as the palmaris longus muscle is an anatomical landmark for operations in this area
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