Temporal Decomposition Studies of GRB Lightcurves

Gamma-ray bursts (GRB) are extremely energetic events and produce highly diverse light curves. Light curves are believed to be resulting from internal shocks reflecting the activities of the GRB central engine. Hence their temporal studies can potentially lead to the understanding of the GRB central engine and its evolution. The light curve variability time scale is an interesting parameter which most models attribute to a physical origin e.g., central engine activity, clumpy circumburst medium, or relativistic turbulence. We develop a statistical method to estimate the GRB minimum variability time scale (MVT) for long and short GRBs detected by GBM. We find that the MVT of short bursts is distinctly shorter than that for long GRBs supprting the possibility of a more compact central engine of the former. We find that MVT estimated by this method is consistent with the shortest rise time of the fitted pulses. Hence we use the fitted pulse rise times to study the evolution of burst variability time scale. Variability time is in turn related to the minimum bulk Lorentz factor. Using this we relate the GRB spectral evolution to the evolution of the variability time scale. %Gamma-ray burst (GRB) light curves are believed to result from internal shocks reflecting the activities of the GRB central engine. %Hence their temporal deconvolution studies can potentially lead to the understanding of the evolution of the minimum variability %time scales which in turn is related to the minimum bulk Lorentz factor. We relate the GRB spectral evolution to the evolution of the %minimum variability time scale.Comment: 5 pages 6 figures. Presented at GRB2012 at Marbella, Spai

Ovarian dysgerminoma: a case report

An ovarian dysgerminoma is a rare, malignant tumour occurring in young women, accounting for 1% to 2% of all primary ovarian neoplasms. A 22 years old female presented with 6 months of amenorrhea and lump in the abdomen. Her physical examination was remarkable with 36 weeks sized huge abdominal mass. Subsequent computed tomography revealed 22×23×32.4 cm mixed density lesion in pelvi-abdominal region and multiple paraaortic and mesenteric lymph node with gross pleural effusion. On further evaluation raised beta-hcG and LDH were noted and hence dysgerminoma was suspected. Total abdominal hysterectomy with right salpingo-ophorectomy with resection of tumour mass with partial omentectomy and lymphadenectomy was performed. Histopathology reports were suggestive of dysgerminoma.

Successful pregnancy after previous uterine rupture

Uterine rupture is a rare and catastrophic event with high fetal and maternal morbidity rate. It is most commonly seen in scarred uterus. Here we present a case of 30 years old female, gravida 3 para 2 living 0 with previous spontaneous uterine rupture at 28-30 weeks with still birth 3 years ago. She underwent emergency laparotomy with repair. She conceived spontaneously, admitted at 20 weeks of gestational age and close antenatal surveillance was done throughout the pregnancy. Corticosteroids was administered. At 36 weeks elective caesarean was planned, delivering via breech presentation to a live male baby of 2.5 kg, Apgar score of 8/10,9/10 at 1 and 5 minutes

Post-partum labial adhesion-a case report

A 22 years old primipara presented after 1.5 years of uncomplicated normal vaginal delivery with complaints of difficulty during intercourse and inability to conceive. Examination revealed labial adhesion connecting left and right labia minora with only 5 mm pinhole opening at the posterior end. Surgical division under anaesthesia resulted in successful complete recovery

Magnetocaloric effect and nature of magnetic transition in nanoscale Pr0.5Ca0.5MnO3

Systematic measurements pertinent to the magnetocaloric effect and nature of magnetic transition around the transition temperature are performed in the 10 nm Pr0.5Ca0.5MnO3 nanoparticles (PCMO10) . Maxwell relation is employed to estimate the change in magnetic entropy. At Curie temperature TC, 83.5 K, the change in magnetic entropy discloses a typical variation with a value 0.57 J/kg K, and is found to be magnetic field dependent. From the area under the curve Delta S vs T, the refrigeration capacity is calculated at TC, 83.5 K and it is found to be 7.01 J/kg. Arrott plots infer that due to the competition between the ferromagnetic and anti ferromagnetic interactions, the magnetic phase transition in PCMO10 is broadly spread over both in temperature as well as in magnetic field coordinates. Upon tuning the particle size, size distribution, morphology, and relative fraction of magnetic phases, it may be possible to enhance the magnetocalorific effect further in PCMO10.Comment: Accepted (Journal of Applied Physics) (In press

Utjecaj brzine doze pulsnoga zračenja na nastanak mikronukleusa u limfocitima periferne ljudske krvi

The micronucleus assay in human peripheral blood lymphocytes is a sensitive indicator of radiation damage and could serve as a biological dosimeter in evaluating suspected overexposure to ionising radiation. Micronucleus (MN) frequency as a measure of chromosomal damage has also extensively been employed to quantify the effects of radiation dose rate on biological systems. Here we studied the effects of 8 MeV pulsed electron beam emitted by Microtron electron accelerator on MN induction at dose rates between 35 Gy min-1 and 352.5 Gy min-1. These dose rates were achieved by varying the pulse repetition rate (PRR). Fricke dosimeter was employed to measure the absorbed dose at different PRR and to ensure uniform dose distribution of the electron beam. To study the dose rate effect, blood samples were irradiated to an absorbed dose of (4.7±0.2) Gy at different rates and cytogenetic damage was quantifi ed using the micronucleus assay. The obtained MN frequency showed no dose rate dependence within the studied dose rate range. Our earlier dose effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic. Therefore, in the event of an accident, dose estimation can be made using linear-quadratic dose response parameters, without adding dose rate as a correction factor.Mikronukleus-test pokazao se osjetljivim pokazateljem oštećenja u limfocitima periferne ljudske krvi te se primjenjuje kao biološki dozimetar posumnja li se na prekomjerno izlaganje ionizirajućem zračenju. Mikronukleusi kao mjera oštećenja kromosoma često se rabe za procjenu učinaka zračenja u biološkim sustavima. Ovdje je istraženo djelovanje pulsnoga elektronskoga snopa od 8 MeV, dobivenog s pomoću elektronskoga akceleratora marke Microtron, na nastanak mikronukleusa u rasponu brzina doza od 35 Gy min-1 do 352.5 Gy min-1. Brzine doza mijenjale su se mijenjajući brzinu ponavljanja pulsa (tzv. pulse repetition rate, krat. PRR). Za mjerenje apsorbirane doze pri različitim PRR-ovima rabio se Frickeov dozimetar. Dozimetrijska su mjerenja također poslužila za ujednačavanje doze elektronskoga snopa. Za istraživanje utjecaja brzine doze, uzorci krvi ozračeni tako da apsorbiraju dozu od (4.7±0.2) Gy pri različitim brzinama doze, a zatim se s pomoću mikronukleus-testa utvrdilo citogenetsko oštećenje. Pokus s pulsnim snopovima energije 8 MeV upućuje na neovisnost broja mikronukleusa o brzinama doze u rasponu ispitanome u ovom istraživanju. Naše ranije istraživanje utjecaja doze pulsnoga elektronskoga zračenja energije 8 MeV upozorilo je na linearni do kvadratni odgovor izmjerenih parametara. Stoga se akcidentalna doza može procijeniti s pomoću linearnih do kvadratnih parametara odgovora na dozu, bez potrebe za korekcijom s pomoću brzine doze

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

We report on isothermal pulsed (20 ms) field magnetization, temperature dependent AC - susceptibility, and the static low magnetic field measurements carried out on 10 nm sized Pr0.5Ca0.5MnO3 nanoparticles (PCMO10). The saturation field for the magnetization of PCMO10 (~ 250 kOe) is found to be reduced in comparison with that of bulk PCMO (~300 kOe). With increasing temperature, the critical magnetic field required to 'melt' the residual charge-ordered phase decays exponentially while the field transition range broadens, which is indicative of a Martensite-like transition. The AC - susceptibility data indicate the presence of a frequency-dependent freezing temperature, satisfying the conventional Vogel-Fulcher and power laws, pointing to the existence of a spin-glass-like disordered magnetic phase. The present results lead to a better understanding of manganite physics and might prove helpful for practical applications

A rare case of uterine myxoid leiomyosarcoma

Myxoid leiomyosarcoma is an uncommon tumour and in most cases, it is recognised only after the surgery. A 65 years old female patient got admitted at our hospital with history of rapidly growing abdominal mass with pain in abdomen since last 3 months. During abdominal examination 32 weeks huge mass was noted and on prevaginal examination mass couldn’t be separated from uterus. LDH was elevated, USG suggestive of vascular tumour of with neoplastic etiology of ovarain origin. CECT was done and findings suggestive of uterine adenocarcinoma with peritoneal carcinomatosis. Exploratory laparotomy with total abdominal hysterectomy with bilateral salphingoopherectomy with omentectomy with debulking surgery was performed. HPR reports suggestive of myxoid leiomyosarcoma with mitotic index of 10 with tumour cell necrosis suggestive of poor prognosis. Post-operative period patient had developed sudden myocardial infarction and shifted to ICU where she died due to ventricular fibrillation.