Non-rotating and rotating neutron stars in the extended field theoretical model

We study the properties of non-rotating and rotating neutron stars for a new set of equations of state (EOSs) with different high density behaviour obtained using the extended field theoretical model. The high density behaviour for these EOSs are varied by varying the $\omega-$meson self-coupling and hyperon-meson couplings in such a way that the quality of fit to the bulk nuclear observables, nuclear matter incompressibility coefficient and hyperon-nucleon potential depths remain practically unaffected. We find that the largest value for maximum mass for the non-rotating neutron star is $2.1M_\odot$. The radius for the neutron star with canonical mass is $12.8 - 14.1$ km provided only those EOSs are considered for which maximum mass is larger than $1.6M_\odot$ as it is the lower bound on the maximum mass measured so far. Our results for the very recently discovered fastest rotating neutron star indicate that this star is supra massive with mass $1.7 - 2.7M_\odot$ and circumferential equatorial radius $12 - 19$ km.Comment: 28 pages, 12 figures. Phys. Rev. C (in press

Correlations in the properties of static and rapidly rotating compact stars

Correlations in the properties of the static compact stars (CSs) and the ones rotating with the highest observed frequency of 1122Hz are studied using a large set of equations of state (EOSs). These EOSs span various approaches and their chemical composition vary from the nucleons to hyperons and quarks in $\beta$-equilibrium. It is found that the properties of static CS, like, the maximum gravitational mass $M_{\rm max}^{\rm stat}$ and radius $R_{1.4}^{\rm stat}$ corresponding to t he canonical mass and supramassive or non-supramassive nature of the CS rotating at 1122 Hz are strongly correlated. In particular, only those EOSs yield the CS rotating at 1122Hz to be non-supramassive for which \left (\frac{M_{\rm max}^{\rm stat}}{M_\odot}\right )^{1/2} \left (\frac{10{\rm km}}{R_{1.4}^{\rm stat}})^{3/2} is greater than unity. Suitable parametric form which can be used to split the $M_{\rm max}^{\rm stat}$ $-$ $R_{1.4}^{\rm stat}$ plane into the regions of different supramassive nature of the CS rotating at 1122Hz is presented. Currently measured maximum gravitational mass 1.76$M_\odot$ of PSR J0437-4715 suggests that the CS rotating at 1122Hz can be non-supramassive provided $R_{1.4}^{\rm stat} \leqslant 12.4$ km.Comment: 13 pages, 4 figures, Appearing in Phys. Rev.

The Dielectric Response of La0.5Ca0.5-xSrxMnO3 (0.1 <= x <= 0.4) Manganites with Different Magnetic Ground States

The dielectric behavior of half doped manganites La0.5Ca0.5-xSrxMnO3 (0.1 \leq \times \leq 0.4) with varying magnetic ground states has been studied. The real part of relative permittivity as a function of temperature {\epsilon}^'(T), exhibits a maximum around the ferromagnetic (TC) and charge ordering transition (TCO) temperatures accompanied with high dielectric losses. The activation energies obtained for x = 0.1 and 0.3 samples below TCO are the same ~ 0.12eV, whereas the relaxation time constant varies in the range 2.8 \times 10-9 s - 6.03 \times 10-11 s. In contrast to samples having x \leq 0.3, for x = 0.4 doping the dielectric permittivity exhibits a strong temperature dependence in the vicinity of magnetic phase transitions. This behavior may be correlated with the presence of competing magnetic interactions (magnetic polarons) close to the magnetic transitions.Comment: 14 pages, 5 figures, To appear in Journal of Applied Physic

Exploring the extended density-dependent Skyrme effective forces for normal and isospin-rich nuclei to neutron stars

We parameterize the recently proposed generalized Skyrme effective force (GSEF) containing extended density dependence. The parameters of the GSEF are determined by the fit to several properties of the normal and isospin-rich nuclei. We also include in our fit a realistic equation of state for the pure neutron matter up to high densities so that the resulting Skyrme parameters can be suitably used to model the neutron star with the "canonical" mass ($\sim 1.4 M_\odot$). For the appropriate comparison we generate a parameter set for the standard Skyrme effective force (SSEF) using exactly the same set of the data as employed to determine the parameters of the GSEF. We find that the GSEF yields larger values for the neutron skin thickness which are closer to the recent predictions based on the isospin diffusion data. The Skyrme parameters so obtained are employed to compute the strength function for the isoscalar giant monopole, dipole and quadrupole resonances. It is found that in the case of GSEF, due to the the larger value of the nucleon effective mass the values of centroid energies for the isoscalar giant resonances are in better agreement with the corresponding experimental data in comparison to those obtained using the SSEF. We also present results for some of the key properties associated with the neutron star of "canonical" mass and for the one with the maximum mass.Comment: 45pages, 16 figure

Consequences of antepartum hemorrhage and its maternal and perinatal outcome

Background: Antepartum haemorrhage, a life-threatening event, is defined as bleeding per vaginum occurring after the fetus has reached the period of viability, considered to be 20 weeks in developed countries and 28 weeks in countries with low resource settings. We evaluated the consequences of antepartum haemorrhage, their maternal and perinatal outcome so as to outline the proper management of patient in order to improve both maternal and perinatal morbidity and mortality.Methods: This one-year prospective study totaled 133 cases of APH fulfilling the inclusion criteria were studied. Data was recorded on the MS excel sheet for further analysis and processing.Results: Total 6693 deliveries were conducted out of which 133 presented as APH and incidence of APH was found out to be 1.98%. Placenta previa was most common. APH was commonly associated with multigravida and most cases were in age group of 26-30 years. Most of the PP and abruption cases were admitted at 34-37 weeks and 31-33 weeks respectively. High risk factors included previous LSCS and D and C, hypertension, multiple pregnancies and malpresentations. Most of the patients underwent preterm LSCS. Most fetal complications were due to prematurity. 58.6% patients were transfused blood. Overall perinatal mortality was 20.1% and maternal mortality was zero.Conclusions: Early diagnoses, timely referrals and transfusion facilities along with trained team of doctors with well-equipped ICU facility goes a long way in avoiding APH related maternak and fetal complications

STUDY ON AGE RELATED MACULAR DEGENERATION (DRY TYPE) IN CONTEXT TO PITTA VIDAGDHA DRISHTI AND ITS AYURVEDIC MANAGEMENT

Age Related Macular Degeneration (ARMD) is the leading cause of the vision loss and blindness in people above 50 years of age. ARMD is characterised by central vision loss, distorted or blurred vision, decreased visual acuity, Central or para-central blind spot (scotoma). An almost similar clinical condition to ARMD is seen in Pitta Vidagdha Dristi. Dry ARMD is more prevalent (90%) and slower in progress than Wet ARMD. The Ayurvedic management of Pitta Vidagdha Drishti is similar to Pittaja Abhishyanda. With this background a specific line of treatment for the Pitta Vidagdha Drisht in Sushruta Samhita is adopted. In this study, total 22 patients, 12 in group A (Triphala Ghrita, Saptamrita Lauha, Rasayana Churna and Shatavari etc.) &amp; 10 in Group B (Control) were registered. The duration of therapy was of 3 months in both the groups. Group A showed better results on ARMD when compared with that of Group B especially on perception of flashes of light (72.23%) &amp; dim light adaptation problem (45.23%). So ARMD (Dry type) can be better managed by Ayurvedic treatment group than the Modern multivitamin group

Unusual Tumors Causing Extrahepatic Portal Venous Obstruction

Extrahepatic portal vein obstruction has been reported to be associated with tumors of liver, bile ducts and pancreas. We report two cases, one with gastric leiomyosarcoma and another with Non Hodgkin’s lymphoma, complicated by portal vein block and presenting with gastric variceal bleeding. Portal vein block in both cases was due to direct vascular infiltration. Development of portal hypertension posed difficulties in management

Novel speech duration modifier for packet based communication system

In this paper, we propose a real-time method for duration modification of speech for packet based communication system. While there is rich literature available on duration modification, it fails to clearly address the issues in real-time implementation of the same. Most of the duration modification methods rely on accurate estimation of pitch marks, which is not feasible in a real-time scenario. The proposed method modifies the duration of Linear Prediction residual of individual frames without using any look-ahead delay and knowledge of pitch marks. In this method, multiples of pitch period is repeated or removed from a frame depending on a scheduling algorithm. The subjective quality of the proposed method was found to be better than waveform similarity overlap and add (WSOLA) technique as well as Linear Prediction Pitch Synchronous Overlap and Add (LP-PSOLA) technique

On the role of different Skyrme forces and surface corrections in exotic cluster-decay

We present cluster decay studies of $^{56}$Ni$^*$ formed in heavy-ion collisions using different Skyrme forces. Our study reveals that different Skyrme forces do not alter the transfer structure of fractional yields significantly. The cluster decay half-lives of different clusters lies within \pm 10% for PCM and \pm 15% for UFM.Comment: 13 pages,6 figures and 1 table; in press Pramana Journal of Physics (2010