Determination of oscillator strength of confined excitons in a semiconductor microcavity

We have achieved a significant experimental Rabi-splitting (3.4 meV) for confined polaritons in a planar semiconductor $\lambda$ microcavity for only a single quantum well (SQW) of GaAs (10 nm) placed at the antinode. The Rabi-splitting phenomena are discussed in detail based on the semiclassical theory, where two coupled harmonic oscillators (excitons and photons) are used to describe the system. In this way, we can obtain the dispersion curve of polaritons, the minimum value for the cavity reflectance and the oscillator strength to reach the strong coupling regime. This approach describes an ensemble of excitons confined in a SQW and includes a dissipation component. The results present a weak coupling regime, where an enhanced spontaneous emission takes place, and a strong coupling regime, where Rabi-splitting in the dispersion curve can be observed. The theoretical results are confronted with experimental data for the reflectance behavior in resonant and off-resonant conditions and present a great accuracy. This allows us to determine the oscillator strength of the confined excitons in the SQW with great precision.Comment: 11 pages, 7 figure

Nonequilibrium dynamics of the three-dimensional Edwards-Anderson spin-glass model with Gaussian couplings: Strong heterogeneities and the backbone picture

We numerically study the three-dimensional Edwards-Anderson model with Gaussian couplings, focusing on the heterogeneities arising in its nonequilibrium dynamics. Results are analyzed in terms of the backbone picture, which links strong dynamical heterogeneities to spatial heterogeneities emerging from the correlation of local rigidity of the bond network. Different two-times quantities as the flipping time distribution and the correlation and response functions, are evaluated over the full system and over high- and low-rigidity regions. We find that the nonequilibrium dynamics of the model is highly correlated to spatial heterogeneities. Also, we observe a similar physical behavior to that previously found in the Edwards-Anderson model with a bimodal (discrete) bond distribution. Namely, the backbone behaves as the main structure that supports the spin-glass phase, within which a sort of domain-growth process develops, while the complement remains in a paramagnetic phase, even below the critical temperature

Lattice Gauge Fixing for Parameter Dependent Covariant Gauges

We propose a non-perturbative procedure to fix generic covariant gauges on the lattice. Varying the gauge parameter, this gauge fixing provides a concrete method to check numerically the gauge dependence of correlators measured on the lattice. The new algorithm turns out to converge with a good efficiency. As a preliminary physical result, we find a sensitive dependence of the gluon propagator on the gauge parameter.Comment: 10 pages (LaTeX2e), 5 eps figure

Backbone structure of the Edwards-Anderson spin-glass model

We study the ground-state spatial heterogeneities of the Edwards-Anderson spin-glass model with both bimodal and Gaussian bond distributions. We characterize these heterogeneities by using a general definition of bond rigidity, which allows us to classify the bonds of the system into two sets, the backbone and its complement, with very different properties. This generalizes to continuous distributions of bonds the well known definition of a backbone for discrete bond distributions. By extensive numerical simulations we find that the topological structure of the backbone for a given lattice dimensionality is very similar for both discrete and continuous bond distributions. We then analyze how these heterogeneities influence the equilibrium properties at finite temperature and we discuss the possibility that a suitable backbone picture can be relevant to describe spin-glass phenomena.Comment: 12 pages, 10 figure

Influence of the Ground-State Topology on the Domain-Wall Energy in the Edwards-Anderson +/- J Spin Glass Model

We study the phase stability of the Edwards-Anderson spin-glass model by analyzing the domain-wall energy. For the bimodal distribution of bonds, a topological analysis of the ground state allows us to separate the system into two regions: the backbone and its environment. We find that the distributions of domain-wall energies are very different in these two regions for the three dimensional (3D) case. Although the backbone turns out to have a very high phase stability, the combined effect of these excitations and correlations produces the low global stability displayed by the system as a whole. On the other hand, in two dimensions (2D) we find that the surface of the excitations avoids the backbone. Our results confirm that a narrow connection exists between the phase stability of the system and the internal structure of the ground-state. In addition, for both 3D and 2D we are able to obtain the fractal dimension of the domain wall by direct means.Comment: 4 pages, 3 figures. Accepted for publication in Rapid Communications of Phys. Rev.

Assessment of indications of caesarean section among high risk women by Robson criteria: a prospective study

Background: Caesarean section (CS) is a surgical intervention for safe delivery other than natural vaginal route. World Health Organization (WHO) has recommended ten group classification systems of Robson criteria which we have used to analyse CS at our center. The objective of the study to analyse the lower section caesarian section (LSCS) data under Robson criteria for implementation in regular practice in tertiary care center and to understand the need of it for future practice.Methods: A prospective analysis done for deliveries in Obstetric Department of Shalby Multispecialty Hospital of central India by Robson ten group classification criteria. The study was carried out for the period of two year from April 2016 to April 2018 including antenatal women attending labour room with high risks or referred cases from other centers.Results: The study reflected overall 196 live birth of high risk cases which were having other co morbidities like pre-eclampsia, eclampsia, hypothyroidism, diabetes, acute viral hepatitis. The data compared with Robsons guidelines and reflected that the centre is dealing with high risk primigravida (47.51%, 35-42% Robson criteria) cases with high CS rate (16.8%, group 5). There was multiple pregnancy, group 8, (2.32 %, >1.5-2% Robson Criteria) and preterm births as in group 10, 18.02 % (5% in Robson Criteria), exclusively high.Conclusions: The Robson criteria help to classify the population handled by the canter to develop the strategies for betterment of services. It has limitation in view of qualitative assessment of the data for comorbidities and severity of the disease

Comorbid depressive disorders in ADHD. the role of ADHD severity, subtypes and familial psychiatric disorders

ObjectiveaaTo evaluate the presence of Major Depressive Disorder (MDD) and Dysthymic Disorder (DD) in a sample of Italian children with Attention Deficit Hyperactivity Disorder (ADHD) and to explore specific features of comorbid depressive disorders in ADHD. MethodsaaThree hundred and sixty-six consecutive, drug-naïve Caucasian Italian outpatients with ADHD were recruited and comorbid disorders were evaluated using DSM-IV-TR criteria. To evaluate ADHD severity, parents of all children filled out the ADHD Rating Scale. Thirty-seven children with comorbid MDD or DD were compared with 118 children with comorbid conduct disorder and 122 without comorbidity for age, sex, IQ level, family psychiatric history, and ADHD subtypes and severity. Resultsaa42 of the ADHD children displayed comorbid depressive disorders: 16 exhibited MDD, 21 DD, and 5 both MDD and DD. The frequency of hyperactive-impulsive subtypes was significantly lower in ADHD children with depressive disorders, than in those without any comorbidity. ADHD children with depressive disorders showed a higher number of familial psychiatric disorders and higher score in the Inattentive scale of the ADHD Rating Scale, than children without any comorbidity. No differences were found for age, sex and IQ level between the three groups. Conclusions: Consistent with previous studies in other countries, depressive disorders affect a significant proportion of ADHD children in Italy. Patient assessment and subsequent treatment should take into consideration the possible presence of this comorbidity, which could specifically increase the severity of ADHD attention problems

Penerapan Model Pembelajaran Inkuiri Terbimbing Untuk Meningkatkan Hasil Belajar Biologi Siswa Kelas VII SMP Negeri 3 Sinaboi Tahun Pelajaran 2015/2016

This research is a research which is aimed to improve students biology studying achievement by implementing guided inqury learning srtategy in class VII SMP N 3 Sinaboi in Academic Year 2015/2016. This research was conducted in April-Mei 2016. The subject of this research was student of class VII of SMP N 3 Sinaboi. The number of students was 36 students (18 boys and 18 girls). The Parameter was students studying achievement consisted of comprehension ability, students passing individually, studens activities and teachers activities. The average of students comprehension ability in cycle 1 was 75.81% (moderate) increased became 81.42% (good). The students passing studying in cycle 1 was 63.88% (pass) increased in cycle 2 became 83.33% (pass). Average of studens activities in cycle 1 was 78.12% (moderate) increased in cycle 2 became 91.66% (very good). Average of teachers activities in cycle 1 was 88.45% (good) increased in cycle 2 became 92.30% (good). From the result of this research it can be concluded that the implementation of guided inquiry can improve students biology studying achievements in class VII SMP N 3 Sinaboi in Academic Year 2015/2016