617 research outputs found
A study on the proportion of hearing impairment among percussionists in Thrissur district of Kerala
Background: Hearing loss is a cause of global concern. Percussionists are exposed to greater levels of continuous or intermittent noise than others. Little is known about the relationship between percussion activity and hearing impairment. The early detection of the same and subsequent management makes a significant reduction in the burden of health care services. The objective was to study the proportion of hearing impairment in percussionists in the district of Thrissur using an IOS based mobile application.Methods: A cross sectional study was done on percussionists from Thrissur district who has experience of more than five years and has no congenital or traumatic hearing loss. A predesigned semi structured questionnaire was given and hearing tests were done using a mobile application U hear in a sound proof setting to understand the current state of hearing ability amoung the percussionists.Results: A total of 39 subjects were involved in our study of which all were males. Mean age of our study population was 30.44+12.04. most of them were diagnosed with at least mild degree of hearing loss of one of the ear or both the ears. 15.4% of them had mild degree of hearing loss, 64.1% had moderate degree of hearing loss and 20.5% had severe hearing loss.Conclusions: The study shows percussionists are more exposed to sounds of various frequencies for longer duration, they are more prone to hearing loss. The study brought out that age is directly proportional to hearing loss, music induced hearing loss progress at a rate proportion to the work experience.
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The Chandrayaan-2 Large Area Soft X-ray Spectrometer (CLASS)
The CLASS experiment on Chandrayaan-2, the second Indian lunar mission, aims tomap the abundance of the major rock forming elements on the lunar surface using the technique of X-ray fluorescence during solar flare events. CLASS is a continuation of the successful C1XS [1] XRF experiment on Chandrayaan-1. CLASS is designed to provide lunar mapping of elemental abundances with a nominal spatial resolution of 25 km (FWHM) from a 200 km polar, circular orbit of Chandrayaan-2
Analytic results for Gaussian wave packets in four model systems: II. Autocorrelation functions
The autocorrelation function, A(t), measures the overlap (in Hilbert space)
of a time-dependent quantum mechanical wave function, psi(x,t), with its
initial value, psi(x,0). It finds extensive use in the theoretical analysis and
experimental measurement of such phenomena as quantum wave packet revivals. We
evaluate explicit expressions for the autocorrelation function for
time-dependent Gaussian solutions of the Schrodinger equation corresponding to
the cases of a free particle, a particle undergoing uniform acceleration, a
particle in a harmonic oscillator potential, and a system corresponding to an
unstable equilibrium (the so-called `inverted' oscillator.) We emphasize the
importance of momentum-space methods where such calculations are often more
straightforwardly realized, as well as stressing their role in providing
complementary information to results obtained using position-space
wavefunctions.Comment: 18 pages, RevTeX, to appear in Found. Phys. Lett, Vol. 17, Dec. 200
Does Quantum Mechanics Clash with the Equivalence Principle - and Does it Matter?
With an eye on developing a quantum theory of gravity, many physicists have
recently searched for quantum challenges to the equivalence principle of
general relativity. However, as historians and philosophers of science are well
aware, the principle of equivalence is not so clear. When clarified, we think
quantum tests of the equivalence principle won't yield much. The problem is
that the clash/not-clash is either already evident or guaranteed not to exist.
Nonetheless, this work does help teach us what it means for a theory to be
geometric.Comment: 12 page
“Chapter 13: Sea Level Change” in Climate Change 2013: The Physical Science Basis: Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change
This chapter considers changes in global mean sea level, regional sea level, sea level extremes, and waves. Confidence in projections of global mean sea level rise has increased since the Fourth Assessment Report (AR4) because of the improved physical understanding of the components of sea level, the improved agreement of process-based models with observations, and the inclusion of ice-sheet dynamical changes
Observational constraints on spatial anisotropy of G from orbital motions
A phenomenological anisotropic variation \Delta G/G of the Newtonian
gravitational coupling parameter G, if real, would affect the orbital dynamics
of a two-body gravitationally bound system in a specific way. We analytically
work out the long-term effects that such a putative modification of the usual
Newtonian inverse-square law would induce on the trajectory of a test particle
orbiting a central mass. Without making any a-priori simplifying assumptions
concerning the orbital configuration of the test particle, it turns out that
its osculating semi-major axis a, eccentricity e, pericenter \varpi and mean
anomaly M undergo long-term temporal variations, while the inclination I and
the node \Omega are left unaffected. Moreover, the radial and the transverse
components of the position and the velocity vectors r and v of the test
particle experience non-vanishing changes per orbit, contrary to the
out-of-plane ones. Then, we compute our theoretical predictions for some of the
major bodies of the solar system by orienting the gradient of G(r) towards the
Galactic Center and keeping it fixed over the characteristic timescales
involved. By comparing our calculation to the latest observational
determinations for the same bodies, we infer \Delta G/G <= 10^-17 over about 1
au. Finally, we consider also the Supermassive Black Hole hosted by the
Galactic Center in Sgr A^* and the main sequence star S2 orbiting it in about
16 yr, obtaining just \Delta G/G <= 10^-2 over 1 kau.Comment: LaTex2e, 18 pages, no figures, 4 tables. Accepted by Classical and
Quantum Gravity (CQG). Typo fixed. Reference update
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of
continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a
fully coherent search, based on matched filtering, which uses the position and rotational parameters
obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto-
noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch
between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have
been developed, allowing a fully coherent search for gravitational waves from known pulsars over a
fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of
11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial
outliers, further studies show no significant evidence for the presence of a gravitational wave signal.
Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of
the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for
the first time. For an additional 3 targets, the median upper limit across the search bands is below the
spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried
out so far
A century of sea level measurements at Newlyn, SW England
The Newlyn Tidal Observatory is the most important sea level station in the UK. It commenced operations in 1915 as part of the Second Geodetic Levelling of England and Wales, and the mean sea level determined from the tide gauge during the first six years (May 1915-April 1921) defined Ordnance Datum Newlyn (ODN) which became the national height datum for the whole of Great Britain. The 100 years of sea level data now available have contributed significantly to many studies in oceanography, geology and climate change. This paper marks the centenary of this important station by reviewing the sea level (and, more recently, detailed land level) measurements and Newlyn’s contributions to UK cartography, geodesy and sea-level science in general. Recommendations are made on how sea and land level measurements at Newlyn might be
enhanced in the future
Computational Modelling of Tissue-Engineered Cartilage Constructs
Cartilage is a fundamental tissue to ensure proper motion between bones and damping of mechanical loads. This tissue often suffers damage and has limited healing capacity due to its avascularity. In order to replace surgery and replacement of joints by metal implants, tissue engineered cartilage is seen as an attractive alternative. These tissues are obtained by seeding chondrocytes or mesenchymal stem cells in scaffolds and are given certain stimuli to improve establishment of mechanical properties similar to the native cartilage. However, tissues with ideal mechanical properties were not obtained yet. Computational models of tissue engineered cartilage growth and remodelling are invaluable to interpret and predict the effects of experimental designs. The current model contribution in the field will be presented in this chapter, with a focus on the response to mechanical stimulation, and the development of fully coupled modelling approaches incorporating simultaneously solute transport and uptake, cell growth, production of extracellular matrix and remodelling of mechanical properties.publishe
Differential Virulence Gene Expression of Group A Streptococcus Serotype M3 in Response to Co-Culture with Moraxella catarrhalis
Streptococcus pyogenes (group A Streptococcus, GAS) and Moraxella catarrhalis are important colonizers and (opportunistic) pathogens of the human respiratory tract. However, current knowledge regarding colonization and pathogenic potential of these two pathogens is based on work involving single bacterial species, even though the interplay between respiratory bacterial species is increasingly important in niche occupation and the development of disease. Therefore, to further define and understand polymicrobial species interactions, we investigated whether gene expression (and hence virulence potential) of GAS would be affected upon co-culture with M. catarrhalis. For co-culture experiments, GAS and M. catarrhalis were cultured in Todd-Hewitt broth supplemented with 0.2% yeast extract (THY) at 37°C with 5% CO2aeration. Each strain was grown in triplicate so that triplicate experiments could be performed. Bacterial RNA was isolated, cDNA synthesized, and microarray transcriptome expression analysis performed. We observed significantly increased (≥4-fold) expression for genes playing a role in GAS virulence such as hyaluronan synthase (hasA), streptococcal mitogenic exotoxin Z (smeZ) and IgG endopeptidase (ideS). In contrast, significantly decreased (≥4-fold) expression was observed in genes involved in energy metabolism and in 12 conserved GAS two-component regulatory systems. This study provides the first evidence that M. catarrhalis increases GAS virulence gene expression during co-culture, and again shows the importance of polymicrobial infections in directing bacterial virulence
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