Pulsed Ultrasound Does Not Affect Recovery From Delayed Onset Muscle Soreness

Aim: To investigate the effects of pulsed Ultrasound (US) in recovery from Delayed Onset Muscle Soreness (DOMS). Methods: Twelve healthy male athletes (mean age 23.83±1.697 year) performed an eccentric exercise protocol of non-dominant elbow flexors to induce muscle soreness on 2 occasions separated by 3 weeks. Subjects in experimental group received pulsed US (1 MHz, intensity 0.8 W/cm2, mark space ratio 1:10), whereas control group received sham US after 24 h, 48 h and 72 h. Perception of muscle soreness, active ROM and muscle strength were the parameters measured at 0 h, 24 h, 48 h and 72 h with the help of VAS, manual goniometer and JONEX muscles master instrument respectively. Results: Post hoc t test analysis revealed significant differences (p <0.05) between 0 h and 72 h in the parameter of ROM (t = 6.18) and muscle power (t = 2.54) as well as between 24 h and 48 h in the parameter of muscle soreness (t = 3.13) in control group. Similar differences were also observed in the experimental group. No significant inter-group differences at α level of 0.05 was observed in any parameter at any level. Conclusion: The pattern of recovery from DOMS was not influenced by the application of pulsed Ultrasound at the parameters discussed here

RVB gauge theory and the Topological degeneracy in the Honeycomb Kitaev model

We relate the Z$_2$ gauge theory formalism of the Kitaev model to the SU(2) gauge theory of the resonating valence bond (RVB) physics. Further, we reformulate a known Jordan-Wigner transformation of Kitaev model on a torus in a general way that shows that it can be thought of as a Z$_2$ gauge fixing procedure. The conserved quantities simplify in terms of the gauge invariant Jordan-Wigner fermions, enabling us to construct exact eigen states and calculate physical quantities. We calculate the fermionic spectrum for flux free sector for different gauge field configurations and show that the ground state is four-fold degenerate on a torus in thermodynamic limit. Further on a torus we construct four mutually anti-commuting operators which enable us to prove that all eigenstates of this model are four fold degenerate in thermodynamic limit.Comment: 12 pages, 3 figures. Added affiliation and a new section, 'Acknowledgements'.Typos correcte

Radio recombination lines from the largest bound atoms in space

In this paper, we report the detection of a series of radio recombination lines (RRLs) in absorption near 26 MHz arising from the largest bound carbon atoms detected in space. These atoms, which are more than a million times larger than the ground state atoms are undergoing delta transitions (n~1009, Delta n=4) in the cool tenuous medium located in the Perseus arm in front of the supernova remnant, Cassiopeia A. Theoretical estimates had shown that atoms which recombined in tenuous media are stable up to quantum levels n~1500. Our data indicates that we have detected radiation from atoms in states very close to this theoretical limit. We also report high signal-to-noise detections of alpha, beta and gamma transitions in carbon atoms arising in the same clouds. In these data, we find that the increase in line widths with quantum number (proportional to n^5) due to pressure and radiation broadening of lines is much gentler than expected from existing models which assume a power law background radiation field. This discrepancy had also been noted earlier. The model line widths had been overestimated since the turnover in radiation field of Cassiopeia A at low frequencies had been ignored. In this paper, we show that, once the spectral turnover is included in the modeling, the slower increase in line width with quantum number is naturally explained.Comment: 5 pages, 4 figures, accepted for publication in MNRA

Magnetic phenomena at and near nu =1/2 and 1/4: theory, experiment and interpretation

I show that the hamiltonian theory of Composite Fermions (CF) is capable of yielding a unified description in fair agreement with recent experiments on polarization P and relaxation rate 1/T_1 in quantum Hall states at filling nu = p/(2ps+1), at and near nu = 1/2 and 1/4, at zero and nonzero temperatures. I show how rotational invariance and two dimensionality can make the underlying interacting theory behave like a free one in a limited context.Comment: Latex 4 pages, 2 figure

Galaxy size trends as a consequence of cosmology

We show that recently documented trends in galaxy sizes with mass and redshift can be understood in terms of the influence of underlying cosmic evolution; a holistic view which is complimentary to interpretations involving the accumulation of discreet evolutionary processes acting on individual objects. Using standard cosmology theory, supported with results from the Millennium simulations, we derive expected size trends for collapsed cosmic structures, emphasising the important distinction between these trends and the assembly paths of individual regions. We then argue that the observed variation in the stellar mass content of these structures can be understood to first order in terms of natural limitations of cooling and feedback. But whilst these relative masses vary by orders of magnitude, galaxy and host radii have been found to correlate linearly. We explain how these two aspects will lead to galaxy sizes that closely follow observed trends and their evolution, comparing directly with the COSMOS and SDSS surveys. Thus we conclude that the observed minimum radius for galaxies, the evolving trend in size as a function of mass for intermediate systems, and the observed increase in the sizes of massive galaxies, may all be considered an emergent consequence of the cosmic expansion.Comment: 14 pages, 13 figures. Accepted by MNRA

An Experimental Study On Load Carrying Capacity Of A Magnetic Bearing

The use of bearing is essential to all types of machines they provide the function of supporting heavier component in a desired position. These bearings have contact with the rotating part and causes surface wear which can be controlled by lubrication. The standards of performance for rotating equipment can be raised by providing robust, cost effective and easy to implement lsquoMagnetic bearingsrsquo. A radial magnetic bearing, consisting of two permanent magnets, is an attractive choice because of its zero wear, negligible friction, and low cost, but it suffers from low load capacity, low radial stiffness, lack of damping and high axial instability. To enhance the radial load and radial stiffness and reduce the axial thrust, a theoretical and experimental study of various radial configurations, including hydrodynamic lubrication to improve dynamic performance of the magnetic bearing is made

On the faint end of the high redshift AGN luminosity function

Using the results of recent optical surveys we conclude that the {\it non}-detection of quasars down to faint magnitudes implies a significant flattening of the high redshift (z~6) optical active galactic nuclei (AGN) luminosity function for M_{1450}>-24.7. We find that all the data are consistent with a faint-end slope for the optical AGN luminosity function of \beta=-2.2 and \beta=-2.8, at the 90% and 99% confidence level respectively, flatter than the bright-end slope of \beta'~ -3.2. We also show that X-ray deep surveys have probed even fainter magnitudes than the optical ones yielding more significant constraints on the shallow faint-end slope of the optical luminosity function. The inclusion of Type II AGN candidates, detected in the Chandra deep fields, hints towards an higher normalization for the total AGN luminosity function, if these sources lie at 5<z <6.5. We then discuss simple theoretical models of AGN formation and evolution in the context of cold dark matter cosmology. The comparison with the total AGN luminosity function favors a redshift-dependent relation between black hole and dark matter halo masses of the type M_BH~M_ halo^\alpha, with 1.3< \alpha< 1.7, compatible with independent studies from statistical analysis and rotation curve measurements. Finally we compute the quasar contribution to reionization to be <9% at z~6, up to ~30% when integrated within 5.5< z<6.5, significantly smaller than that from galaxies.Comment: 19 pages, 5 figures, revised version for Ap

INVESTIGATION OF MACHINING PARAMETERS IN CNC TURNING USING RESPONSE SURFACE METHODOLOGY (RSM)

CNC turning is one among the metal cutting process in which quality of the finished product depends mainly upon the machining parameters such as feed, speed, depth of cut, type of coolant used, types of inserts used etc. Similarly the work piece material plays an important role in the metal cutting process. This study involves in identifying the optimized parameters in CNC turning of Aluminium and Stainless Steel. To identify and measure the formation of burrs samples are examined under scanning electron microscope (SEM).The optimization techniques used in this study are Response surface methodology, and Genetic algorithm. These optimization techniques are very helpful in identifying the optimized control factors with high level of accuracy. Brass and Copper (Non Ferrous) materials are taken for this investigation

OPTIMIZATION OF MACHINING PARAMETERS FOR ECM USING GREY RELATIONAL ANALAYSIS

The use of Electrochemical Machining (ECM) as one of the best machining techniques for machining and electrically conducting tough and difficult to machine materials with appropriate machining parameters. In recent years, the utilization of titanium and its alloys, especially grade 2 materials in many different engineering fields has undergone a tremendous increase. The ECM process has a potential in the machining of grade 2. This work describes the development of the second order, non-linear mathematical model without interaction terms for establishing the relationship between machining parameters, such as electrolyte concentration, current, applied voltage and feed rate, with the dominant machining process criteria, namely the material removal rate (MRR) and surface roughness (SR). In this paper, an attempt has been made to machine the grade 2 material (LM6 Al/B2C) using the ECM process. The effects of various process/product parameters like applied voltage, feed rate, electrolyte concentration and percentage of reinforcement on the Material Removal Rate (MRR), surface roughness (SR) were observed. Multiple Regression models are developed based on Grey relational analysis using the relevant experimental data, which are obtained during an ECM operation on grade 2. Validity and creativeness of the developed mathematical models have also been tested through analysis of variance. Graphs, describing the direct effects of process variables on the responses, were plotted. The Optimal combination of these predominant machining process parameters is obtained from these mathematical models considering MRR and SR simultaneously for higher material removal rate and lower surface roughness value. The confirmation results reveal that, there is considerable improvement in Material Removal Rate, Grey relational grade are improved by 08.33 %, 41.17 % and 81.77 % respectively. It is observed that the machining performance can be effectively improved with respect to initial parametric setting. A statistical technique, fractional factorial experiments and analysis of variance (ANOVA), has been employed to investigate the influence of cutting parameters

Determination of gestational age: correlation between foetal biometry and transverse cerebellar diameter in women with uncomplicated pregnancy

Background: Transverse Cerebellar Diameter (TCD) serves as a reliable predictor of gestational age in foetus and is a standard against which aberrations in other foetal parameters can be compared, especially when the GA cannot be determined by the date of last menstrual period or early pregnancy scan, TCD is one foetal parameter that has remained consistently superior in predicting gestational age in both singleton and twin gestation. Aim of the study was to assess and evaluate the effectiveness of transverse cerebellar diameter by using ultrasonography for determining the gestational age of the foetus.Methods: A cross-sectional study was done in 100 uncomplicated pregnant patients between the 15th week of gestation to term referred from routine antenatal clinic in outpatient and in-patient department of Obstetrics and Gynecology department of Vinayaka Mission Krupananda Variyar medical college and hospital, Salem during study period April 2015-March 2016. TCD is obtained in the axial plane in the cerebellar view i.e. with a slight rotation of the transducer approximately 30° from the conventional thalamic plane where the biparietal diameter is measured using the cavum septi pellucidi, third ventricle and thalami as landmarks.Results: The correlation of transcerebellar diameter (TCD) with that of BPD (bi-parietal diameter) had shown a perfect positive correlation (r = 0.978) and a similar type of correlation was also seen with HC (head circumference) (r = 0.979), AC (abdominal circumference) (r = 0.966), FL (femur length) (r = 0.976) and USG GA (ultrasonogram gestational age) (r = 0.983).Conclusions: In the normally developing foetus, the TCD increases in a linear fashion with advancing gestational age. The data of this study suggest foetal TCD on ultrasound is a reliable predictive biometric parameter of gestational age