Quantum Monte Carlo calculations of electroweak transition matrix elements in A = 6,7 nuclei

Green's function Monte Carlo calculations of magnetic dipole, electric quadrupole, Fermi, and Gamow-Teller transition matrix elements are reported for A=6,7 nuclei. The matrix elements are extrapolated from mixed estimates that bracket the relevant electroweak operator between variational Monte Carlo and GFMC propagated wave functions. Because they are off-diagonal terms, two mixed estimates are required for each transition, with a VMC initial (final) state paired with a GFMC final (initial) state. The realistic Argonne v18 two-nucleon and Illinois-2 three-nucleon interactions are used to generate the nuclear states. In most cases we find good agreement with experimental data.Comment: v2: minor corrections to text and figure

The no-core shell model with general radial bases

Calculations in the ab initio no-core shell model (NCSM) have conventionally been carried out using the harmonic-oscillator many-body basis. However, the rapid falloff (Gaussian asymptotics) of the oscillator functions at large radius makes them poorly suited for the description of the asymptotic properties of the nuclear wavefunction. We establish the foundations for carrying out no-core configuration interaction (NCCI) calculations using a basis built from general radial functions and discuss some of the considerations which enter into using such a basis. In particular, we consider the Coulomb-Sturmian basis, which provides a complete set of functions with a realistic (exponential) radial falloff.Comment: 7 pages, 3 figures; presented at Horizons on Innovative Theories, Experiments, and Supercomputing in Nuclear Physics 2012, New Orleans, Louisiana, June 4-7, 2012; submitted to J. Phys. Conf. Se

Semileptonic Decays of Heavy Lambda Baryons in a Quark Model

The semileptonic decays of Lambda_c and Lambda_b are treated in the framework of a constituent quark model. Both nonrelativistic and semirelativistic Hamiltonians are used to obtain the baryon wave functions from a fit to the spectra, and the wave functions are expanded in both the harmonic oscillator and Sturmian bases. The latter basis leads to form factors in which the kinematic dependence on q^2 is in the form of multipoles, and the resulting form factors fall faster as a function of q^2 in the available kinematic ranges. As a result, decay rates obtained in the two models using the Sturmian basis are significantly smaller than those obtained using the harmonic oscillator basis. In the case of the Lambda_c, decay rates calculated using the Sturmian basis are closer to the experimentally reported rates. However, we find a semileptonic branching fraction for the Lambda_c to decay to excited Lambda* states of 11% to 19%, in contradiction with what is assumed in available experimental analyses. Our prediction for the Lambda_b semileptonic decays is that decays to the ground state Lambda_c provide a little less than 70% of the total semileptonic decay rate. For the decays Lambda_b to Lambda_c, the analytic form factors we obtain satisfy the relations expected from heavy-quark effective theory at the non-recoil point, at leading and next-to-leading orders in the heavy-quark expansion. In addition, some features of the heavy-quark limit are shown to naturally persist as the mass of the heavy quark in the daughter baryon is decreased.Comment: 51 pages, 8 figures, submitted to Physical Review

The Role of Δ(1232)\Delta(1232) in Two-pion Exchange Three-nucleon Potential

In this paper we have studied the two-pion exchange three-nucleon potential $(2\pi E-3NP)$ using an approximate $SU(2) \times SU(2)$ chiral symmetry of the strong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagangian are supplemented with contributions from the well-known $\sigma$-term and the $\Delta(1232)$ exchange. It is the role of the $\Delta$-resonance in $2\pi E-3NP$, which we have investigated in detail in the framework of the Lagrangian field theory. The $\Delta$-contribution is quite appreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds $|Z| \leq 1/2$. We find that the $\Delta$-contribution to the important parameters of the $2\pi E-3NP$ depends on the choice of a value for Z, although the correction to the binding energy of triton is not expected to be very sensitive to the variation of Z within its bounds.Comment: 14 pages, LaTe

Heavy Baryons in a Quark Model

A quark model is applied to the spectrum of baryons containing heavy quarks. The model gives masses for the known heavy baryons that are in agreement with experiment, but for the doubly-charmed baryon Cascade_{cc}, the model prediction is too heavy. Mixing between the Cascade_Q and Cascade_Q^\prime states is examined and is found to be small for the lowest lying states. In contrast with this, mixing between the Cascade_{bc} and Cascade_{bc}^\prime states is found to be large, and the implication of this mixing for properties of these states is briefly discussed. We also examine heavy-quark spin-symmetry multiplets, and find that many states in the model can be placed in such multiplets. We compare our predictions with those of a number of other authors.Comment: Version published in International Journal of Modern Physics

Clinico-histopathological correlation of abdominal hysterectomy

 Background: Hysterectomy is the most common gynaecological procedure performed. Abdominal hysterectomy remains the most common approach though recently there has been preference towards laparoscopic hysterectomy. It is still considered as the treatment of choice for benign lesion such as leiomyoma, adenomyosis, extensive pelvic infection or adhesions, dysfunctional uterine bleeding and obstetric complications. Objectives were to correlate the indications of abdominal hysterectomy to histopathological findings thus, determining histologically confirmed preoperative clinical diagnosis.Methods: This study was conducted at the department of obstetrics and gynaecology, Bangabandhu Sheikh Mujib medical university, Dhaka from August 2010 to January 2011. This is a descriptive analysis of the patients who had undergone abdominal hysterectomy during the study period.Results: One hundred patients undergoing abdominal hysterectomy were studied. Data were recorded on structured proforma, including demographic characteristics, clinical features and indications of the procedure. In. our study, it was observed that the most common clinical diagnosis was leiomyoma of uterus 52 (52%). Other clinical diagnosis was DUB in 30 cases (30%), adenomyosis in 7 cases (7%), endometriosis in 6 cases (6%). Pelvic inflammatory disease in 3 cases (3%), endometrial polyp (2%). Abdominal hysterectomy was the single approach done in these cases. Clinical, radiological as well as histopathology report correlated uterine leiomyoma very well and it was about 94.23%, while DUB was a disease of exclusion. In 53 cases combined pathology was found.Conclusions: Hysterectomy is currently the most widely performed major operation in gynaecology and histopathology is mandatory for ensuring diagnosis and management. With the improvement in the different organ preserving options, hysterectomy in benign disease should only be opted when all the other conservative options failure.

Frequency and pattern of gynecological problems of adolescent girls attending outpatient department, department of obstetrics and gynecology, Bangabandhu Sheik Mujib Medical University, Bangladesh

Background: Adolescent is a stage of development tangent, like a bridge of childhood and adulthood. It is the healthiest age group of our society which is almost 20% of our total population. World health organization (WHO) defines adolescents are in the 10-19 year in age group. One of the major physiological changes that take place in adolescent girls is the onset of menarche, which is often associated with problems of irregular menstruation, excessive bleeding and dysmenorrhea.Methods: This cross-sectional observational study was carried out in 668 female adolescent aged 10-19 years irrespective of their marital status visiting the OPD of obstetrics and gynecology department of BSMMU. All data was analyzed using SPSS program version 22.0.Results: Results were expressed in frequencies or percentages. Of the 668 adolescent girls, 418 (62.6%) had different type of menstrual disorder. Of these 418 cases about 127 (30.38%) of them were a case of puberty menorrhagia, 109 (26.07%) cases were oligomenorrhoea and 91 (21.77%) were amenorrhea. Other presentations were pre-vaginal discharge, vulval itching, lower abdominal pain, dysuria, feeling lump in lower abdomen, mastalgia, feeling lump in the breast, discharge from breast, acne, hirsutism.Conclusions: This study shows more than half of adolescent girls are having menstrual disorder. Adolescent gynecology needs increased awareness and greater attention to improve the quality of their life. Setting up a separate adolescent clinic is necessary for efficient management of adolescent problem

Recent models for adaptive personality differences: a review

In this paper we review recent models that provide adaptive explanations for animal personalities: individual differences in behaviour (or suites of correlated behaviours) that are consistent over time or contexts. We start by briefly discussing patterns of variation in behaviour that have been documented in natural populations. In the main part of the paper we discuss models for personality differences that (i) explain animal personalities as adaptive behavioural responses to differences in state, (ii) investigate how feedbacks between state and behaviour can stabilize initial differences among individuals and (iii) provide adaptive explanations for animal personalities that are not based on state differences. Throughout, we focus on two basic questions. First, what is the basic conceptual idea underlying the model? Second, what are the key assumptions and predictions of the model? We conclude by discussing empirical features of personalities that have not yet been addressed by formal modelling. While this paper is primarily intended to guide empiricists through current adaptive theory, thereby stimulating empirical tests of these models, we hope it also inspires theoreticians to address aspects of personalities that have received little attention up to now