Recent direct measurement of the Top quark mass and quasi-infrared fixed point

We note that the recent direct measurement of the top quark mass at $173.3 \pm 5.6 (stat) \pm 6.2 (syst)$ by D0 collaboration severely constrains the theoretically attractive infra-red fixed point scenario of the top quark Yukawa coupling in supersymmetric GUTs. For one-step unified models the above mentioned measurement bounds the arbitrary but experimentally determinable parameter $\tan \beta$ to the range $1.3 \le \tan \beta \le 2.1$. Further crunch on the top quark mass may determine $\tan \beta$ even more accurately within the fixed point scenario. On the other hand an experimental value of $\tan \beta > 2.1$ will rule out the fixed point scenario bounding $h^2_t(M_X)/4 \pi$ to 0.022 from above.Comment: 7 pages, Latex with epsf style, 1 figure, captions.st

DEVELOPMENT AND IN VIVO EVALUATION OF GASTRORETENTIVE FLOATING TABLETS OF ANTIPSYCHOTIC DRUG RISPERIDONE

Objective: The objective of this research work was to formulate and evaluate the floating drug delivery system containing Risperidone, to improve oral bioavailability by increasing gastric residence time.Methods: Total fifteen formulations of Risperidone floating tablets were prepared by direct compression method using different grades of HPMC polymers, Gelucire, Polyox and NaHCO3. In vivo radiographic studies were performed in human volunteers by incorporating barium sulphate.Results: The prepared tablets were characterized and found to exhibit satisfactory physicochemical characteristics. All the prepared batches showed good in vitro buoyancy with low floating lag time. It was observed that the tablets remained buoyant for more than 12h. Optimized formulation (F15) consisting of HPMC K100M, WSR 301, Gelucire 50/13 and NaHCO3, followed diffusion controlled zero-order kinetics and non-fickian transport of the drug. FTIR and DSC studies revealed the absence of any chemical interaction between drug and polymers used. The in vivo radiographic studies revealed that the tablets remained in the stomach for 6h in fasting human volunteers. In vivo bioavailability studies performed in healthy human volunteers and Tmax, Cmax, AUC was calculated and confirmed significant improvement in bioavailability when compared with marketed formulation Respidon 2.Conclusion: The data obtained thus suggests that floating delivery system of Risperidone can be successfully designed to give controlled drug delivery and improved oral bioavailability

Low Energy Neutrino Physics after SNO and KamLAND

In the recent years important discoveries in the field of low energy neutrino physics (E$_\nu$ in the $\approx$ MeV range) have been achieved. Results of the solar neutrino experiment SNO show clearly flavor transitions from $\nu_e$ to $\nu_{\mu,\tau}$. In addition, the long standing solar neutrino problem is basically solved. With KamLAND, an experiment measuring neutrinos emitted from nuclear reactors at large distances, evidence for neutrino oscillations has been found. The values for the oscillation parameters, amplitude and phase, have been restricted. In this paper the potential of future projects in low energy neutrino physics is discussed. This encompasses future solar and reactor experiments as well as the direct search for neutrino masses. Finally the potential of a large liquid scintillator detector in an underground laboratory for supernova neutrino detection, solar neutrino detection, and the search for proton decay $p \to K^+ \nu$ is discussed.Comment: Invited brief review, World Scientific Publishing Compan

Nutritional evaluation of varying protein: energy ratios in feeds for Indian white shrimp Penaeus (Fenneropenaeus) indicus

Six experiments of six weeks duration were conducted in controlled conditions in the Indian white shrimp Fenneropenaeus indicus early juveniles (~0.040 mg initial weight). A common ingredient mixture (CIM) consisting of albumin (chicken egg), fish meal, shrimp meal, clam meal and deoiled ground nut oil cake was formulated and incorporated in all feeds at varying levels to obtain the requisite protein: energy combinations. Eight feeds tested in each experiment were formulated by incorporating CIM, cellulose (filler), tapioca flour (starch, binder), oil, mineral mixture, vitamin mixture and other additives viz., cholesterol and lecithin. The six protein levels fixed were 250 g kg-1 to 500 g kg-1 with 50 g kg-1 increments for each experiment. The gross energy (GE) levels in the eight dietary treatments for each level of protein varied from 290 kcal 100g-1 to 430 kcal 100g-1 and the digestible energy levels varied from198 – 300 kcal 100g-1. Growth, relative growth rate (RGR), absolute growth rate (AGR), food conversion efficiency (FCE), food conversion ratio (FCR), survival and initial and final body composition were monitored and analysed. One-way analysis of variance (ANOVA) followed by comparison of means was done to examine statistically significant differences between treatments and second degree polynomial regression of the from y = a + bx + cx2 was fitted with the data for RGR on P/E ratio (mg protein kcal-1), RGR on GE and RGR on DE to derive the optimum RGR, GE, DE and P/E. The results showed that growth of shrimp was highest with 450 g kg-1 protein and 363 kcal 100g- 1 GE, 276 kcal 100g-1 DE with a P/E of 124. Theoretical optima derived confirmed this observation with optimal values of 360 kcal 100g-1 GE, 275 kcal 100g-1 DE and a P/E ratio of 125. However, similar response in growth with feeds containing 350 - 450 g kg-1 protein indicating GE requirement of 362 – 371 kcal 100g-1 and DE requirement of 262 – 276 kcal100g-1 suggested a protein sufficiency of 350 g kg-1 with a P/E ratio of 98- 103 without major variations in the whole body composition

Eliminating the d=5 proton decay operators from SUSY GUTs

A general analysis is made of the question whether the d=5 proton decay operators coming from exchange of colored Higgsinos can be completely eliminated in a natural way in supersymmetric grand unified models. It is shown that they can indeed be in SO(10) while at the same time naturally solving the doublet-triplet splitting problem, having only two light Higgs doublets, and using no more than a single adjoint Higgs field. Accomplishing all of this requires that the vacuum expectation value of the adjoint Higgs field be proportional to the generator I_{3R} rather than to B-L, as is usually assumed. It is shown that such models can give realistic quark and lepton masses. We also point out a new mechanism for solving the \mu problem in the context of SO(10) SUSY GUTs.Comment: 24 pages in LaTeX, with 3 figure

Constraining Proton Lifetime in SO(10) with Stabilized Doublet-Triplet Splitting

We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos--Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The \mu term of order TeV is found to be naturally induced. A Z_2-assisted anomalous U(1)_A gauge symmetry plays a crucial role in achieving these results. The threshold corrections to alpha_3(M_Z), somewhat surprisingly, are found to be controlled by only a few effective parameters. This leads to a very predictive scenario for proton decay. As a novel feature, we find an interesting correlation between the d=6 (p\to e^+\pi^0) and d=5 (p\to \nu-bar K+) decay amplitudes which allows us to derive a constrained upper limit on the inverse rate of the e^+\pi^0 mode. Our results show that both modes should be observed with an improvement in the current sensitivity by about a factor of five to ten.Comment: 21 pages LaTeX, 2 figures, Few explanatory sentences and three new references added, minor typos corrected