Transmission through a n interacting quantum dot in the Coulomb blockade regime

The influence of electron-electron (e-e) interactions on the transmission through a quantum dot is investigated numerically for the Coulomb blockade regime. For vanishing magnetic fields, the conductance peak height statistics is found to be independent of the interactions strength. It is identical to the statistics predicted by constant interaction single electron random matrix theory and agrees well with recent experiments. However, in contrast to these random matrix theories, our calculations reproduces the reduced sensitivity to magnetic flux observed in many experiments. The relevant physics is traced to the short range Coulomb correlations providing thus a unified explanation for the transmission statistics as well as for the large conductance peak spacing fluctuations observed in other experiments.Comment: Final version as publishe

A study of histopathological spectrum of central nervous system lesions at a tertiary health care center of South Gujarat, India

Background: Central nervous system lesions can have varied aetiology like infectious, inflammatory and neoplastic. Establishing an accurate aetiology is essential for timely diagnosis and neurosurgical intervention. The annual incidence of tumours of CNS ranges from 10 to 17 per 100,000 people for intracranial tumours and 1 to 2 per 100,000 people for intraspinal tumours; the majority of these are primary tumours, and only one fourth to one half are metastastic. The present study attempts to provide preliminary data on morphological patterns of intracranial lesions and to study clinicopathological spectrum.Methods: The present study was carried out at a tertiary care center from January 2015 to September 2017. A total of 65 cases of CNS lesions were analyzed. In case of CNS tumours reporting were done according to WHO criteria for classification and grading.Results: Out of 65 cases studied, 51 cases (78.46%) were of neoplastic lesions and 14 cases (21.54%) of non-neoplastic lesions. Among 14 cases of non-neoplastic lesions 2 cases were of reactive/cystic lesions, 4 cases  were of infective lesions, and 8 cases were of congenital lesions. In the present study, out of 51 neoplastic cases most common cases were of astrocytoma.Conclusions: The exact histopathological diagnosis of Central Nervous system lesions is essential to predict the prognosis and treatment. Management strategies and prognosis of tumours depends on the correlation of factors like the types, grades of tumours, its location, size and stage of development

Jyotismati Taila and Ashtamangal Ghrita Nasya in the management of Mental Retardation - A Comparative Study

Mental retardation is still elusive to researchers due to multidimensionality of psychological, medical, educational and social aspects, which alters mental functions and capability. Mental sub capability divided in 4 categories, Mild, Moderate, Severe and Profound. Chief aim of management of mental retardation is to make child more capable of performing common activities of everyday life by positive improvement in mental sub-capability. Mental retardation required multidimensional management approach. Present study focused on medicinal intervention, particularly analysis of comparative effectiveness of selected drug formulations (Astamangalghrita and Jyotismatitaila) from classical text of Ayurveda. Study design with the aims to compare the effectiveness of Jyotismatitaila and Astamangal Ghrita Nasya on Mental retardation. Assessment were based on Mental Status Score and IQ score taken before starting of treatment and after completion of treatment in both group. Obtained data was analyzed statistically. In this study, from result we conclude that both drugs are effective to improve Mental Status parameter and in IQ, but higher percentage and significance wise Jyotismati Taila had better result than Astamangal Ghrita Nasya

Absence of bimodal peak spacing distribution in the Coulomb blockade regime

Using exact diagonalization numerical methods, as well as analytical arguments, we show that for the typical electron densities in chaotic and disordered dots the peak spacing distribution is not bimodal, but rather Gaussian. This is in agreement with the experimental observations. We attribute this behavior to the tendency of an even number of electrons to gain on-site interaction energy by removing the spin degeneracy. Thus, the dot is predicted to show a non trivial electron number dependent spin polarization. Experimental test of this hypothesis based on the spin polarization measurements are proposed.Comment: 13 pages, 3 figures, accepted for publication in PRL - a few small change

Signatures of spin pairing in a quantum dot in the Coulomb blockade regime

Coulomb blockade resonances are measured in a GaAs quantum dot in which both shape deformations and interactions are small. The parametric evolution of the Coulomb blockade peaks shows a pronounced pair correlation in both position and amplitude, which is interpreted as spin pairing. As a consequence, the nearest-neighbor distribution of peak spacings can be well approximated by a smeared bimodal Wigner surmise, provided that interactions which go beyond the constant interaction model are taken into account.Comment: 5 pages, 3 figure

Perfect Lattice Actions for Staggered Fermions

We construct a perfect lattice action for staggered fermions by blocking from the continuum. The locality, spectrum and pressure of such perfect staggered fermions are discussed. We also derive a consistent fixed point action for free gauge fields and discuss its locality as well as the resulting static quark-antiquark potential. This provides a basis for the construction of (classically) perfect lattice actions for QCD using staggered fermions.Comment: 30 pages, LaTex, 10 figure

FORMULATION AND EVALUATAION OF COLON TARGETED MATRIX TABLET OF NAPROXEN

Objectives: The objective of the present study is to formulate the Colon targeted delivery containing Naproxen for chronopharmaceutical drug delivery system (ChrDDS) for treatment of rheumatoid arthritis, which are influenced by circadian rhythm. Chronopharmaceutical drug delivery system is capable of delivering drug when and where drug required most. Naproxen would remain in the GIT Fluid, intestinal fluid and it will liberate only in colonic fluid and gives better absorption. Methods: The matrix core tablets of Naproxen were prepared by direct compression method by using Crosspovidone as superdisintegrant. From those optimesd batch core tablet is further going for coating. Coating was carried out by using natural gums like Xanthan gum, Guar gum, Chitosan and Pectin alone and in combination. Results: From the experimental work Crosspovidone shows good drug release. Coating done by combination of Xanthan Gum and Chitosan shows better drug release (98.24%) in sustained release manner than other natural gums like Guar gum and pectin. Conclusion: From the results obtained, it was concluded that the programmable Chronopharmaceutical drug release has been achieved from Crosspovidone containing core tablet compressed coated by combination of Xanthan gum and Chitosan over a 10 hrs period, consistent with the demands of chronotherapeutic drug delivery for rheumatoid arthritis

Density Modulations and Addition Spectra of Interacting Electrons in Disordered Quantum Dots

We analyse the ground state of spinless fermions on a lattice in a weakly disordered potential, interacting via a nearest neighbour interaction, by applying the self-consistent Hartree-Fock approximation. We find that charge density modulations emerge progressively when r_s >1, even away from half-filling, with only short-range density correlations. Classical geometry dependent "magic numbers" can show up in the addition spectrum which are remarkably robust against quantum fluctuations and disorder averaging.Comment: 4 pages, 3 eps figure