Evolution of Primordial Black Hole Mass Spectrum in Brans-Dicke Theory

We investigate the evolution of primordial black hole mass spectrum by including both accretion of radiation and Hawking evaporation within Brans-Dicke cosmology in radiation, matter and vacuum-dominated eras. We also consider the effect of evaporation of primordial black holes on the expansion dynamics of the universe. The analytic solutions describing the energy density of the black holes in equilibrium with radiation are presented. We demonstrate that these solutions act as attractors for the system ensuring stability for both linear and nonlinear situations. We show, however, that inclusion of accretion of radiation delays the onset of this equilibrium in all radiation, matter and vacuum-dominated eras.Comment: 18 pages, one figur

Black holes and a scalar field in an expanding universe

We consider a model of an inhomogeneous universe including a massless scalar field, where the inhomogeneity is assumed to consist of many black holes. This model can be constructed by following Lindquist and Wheeler, which has already been investigated without including scalar field to show that an averaged scale factor coincides with that of the Friedmann model. In this work we construct the inhomogeneous universe with an massless scalar field, where we assume that the averaged scale factor and scalar field are given by those of the Friedmann model including a scalar field. All of our calculations are carried out in the framework of Brans-Dicke gravity. In constructing the model of an inhomogeneous universe, we define the mass of a black hole in the Brans-Dicke expanding universe which is equivalent to ADM mass if the mass evolves adiabatically, and obtain an equation relating our mass to the averaged scalar field and scale factor. As the results we find that the mass has an adiabatic time dependence in a sufficiently late stage of the expansion of the universe, and that the time dependence is qualitatively diffenrent according to the sign of the curvature of the universe: the mass increases decelerating in the closed universe case, is constant in the flat case and decreases decelerating in the open case. It is also noted that the mass in the Einstein frame depends on time. Our results that the mass has a time dependence should be retained even in the general scalar-tensor gravitiy with a scalar field potential. Furthermore, we discuss the relation of our results to the uniqueness theorem of black hole spacetime and gravitational memory effect.Comment: 16 pages, 3 tables, 5 figure

Comment on "Probabilistic Quantum Memories"

This is a comment on two wrong Phys. Rev. Letters papers by C.A. Trugenberger. Trugenberger claimed that quantum registers could be used as exponentially large "associative" memories. We show that his scheme is no better than one where the quantum register is replaced with a classical one of equal size. We also point out that the Holevo bound and more recent bounds on "quantum random access codes" pretty much rule out powerful memories (for classical information) based on quantum states.Comment: REVTeX4, 1 page, published versio

Maternal and perinatal outcome in women with threatened abortion in first trimester

Background: Threatened abortion in first trimester is a risk factor for complications in the latter half of pregnancy. The present study was undertaken to identify the pregnancy outcome in women with threatened abortion in the first trimester of pregnancy in a tertiary hospital.Methods: A retrospective-prospective observational study was done on 100 pregnant women with a history of threatened abortion in the first trimester. Maternal outcome in the form of pregnancy loss, APH/PPH, Preeclampsia/eclampsia, PROM/PPROM, term delivery and retained placenta were studies. Perinatal outcome in the form of preterm delivery, Low Birth Weight, IUGR and IUFD were studied. Analysis of the data was done using SPSS version 17.Results: Threatened abortion in first trimester was found to be associated with increased risks of LBW, preterm births, PPROM, and PIH. Out of 100 patients, preterm births and LBW babies were found in 21% and 13% of patients respectively. 15% of the cases developed PIH, out of which gestational hypertension and pre-eclampsia were 8% and 6% respectively.Conclusions: Pregnant women with first trimester threatened abortion are at increased risk for spontaneous loss and adverse pregnancy outcomes. Knowledge of these risks may help the obstetricians to manage these cases vigorously in the antepartum period and do timely interventions as needed for a healthy mother and baby

The effectiveness of b-lynch sutures in management of atonic postpartum haemorrhage during caesarean section

Background: Surgical methods of controlling uterine bleeding by inserting compression sutures have been developed to reduce the incidence of emergency hysterectomy and to preserve fertility in patients with atonic postpartum haemorrhage (PPH).  The aim of the study was to determine the efficacy of B-Lynch suture in management of atonic PPH and to determine whether timely application of B-Lynch suture in uncontrolled atonic PPH obviates the need for hysterectomy and thus help in pursuing subsequent fertility.Methods: A prospective observational study of 30 patients who underwent B-Lynch suturing for atonic PPH during lower segment cesarian section (LSCS), refractory to medical line of management was conducted. The amount of blood loss, need for blood transfusion and hysterectomy were noted. The patients were followed-up for 6 months for any late postoperative complications and for any infertility issues.Results: The procedure was successful in 100% of the cases following failure of medical line of management. None of them required hysterectomy or uterine devascularisation. All patients had uneventful puerperium. No evidence of ischemic necrosis or pyometra on assessment of patients on 6 month follow up.Conclusions: This procedure proves to be a valuable addition for surgical treatment of atonic PPH and great advantage in young patients with restoration of future fertility with the added advantage of lesser time of application, lesser blood loss, lesser blood transfusion, lesser skill required. Thus, B-Lynch suturing can be adopted as a mid-step before resorting to uterine devascularisation or hysterectomy when medical line of management fails