4,120 research outputs found
Low Energy Neutrino Physics after SNO and KamLAND
In the recent years important discoveries in the field of low energy neutrino
physics (E in the MeV range) have been achieved. Results of the
solar neutrino experiment SNO show clearly flavor transitions from to
. 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 is discussed.Comment: Invited brief review, World Scientific Publishing Compan
Search for C P violation in the D + → π + π 0 decay at Belle
We search for CP violation in the charged charm meson decay D+→π+π0, based on a data sample corresponding to an integrated luminosity of 921 fb−1 collected by the Belle experiment at the KEKB e+e− asymmetric-energy collider. The measured CP-violating asymmetry is [+2.31±1.24(stat)±0.23(syst)]%, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results
Influence of gas flow rate on liquid distribution in trickle-beds using perforated plates as liquid distributors
Two wire mesh tomography devices and a liquid collector were used to study
the influence of the gas flow rate on liquid distribution when fluids
distribution on top of the reactor is ensured by a perforated plate. In
opposition to most of the studies realized by other authors, conditions in
which the gas has a negative impact in liquid distribution were evidenced.
Indeed, the obtained results show that the influence of gas flow rate depends
on the quality of the initial distribution, as the gas forces the liquid to
"respect" the distribution imposed at the top of the reactor. Finally, a
comparison between the two measuring techniques shows the limitations of the
liquid collector and the improper conclusions to which its use could lead
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
In Vitro Antioxidant Activity of Bark Extracts of Rhizophora mucronata
The present study was conducted to evaluate the antioxidant activity of medicinal plant Rhizophora mucronata (R. mucronata). Shade dried stem bark of R. mucronata was powdered and extracted with 95% ethanol and water by cold extraction method. The total phenolic and flavonoid contents of water and ethanol extract of air dried stem bark was estimated by using spectrometric method. Antioxidant activity of R. mucronata was determined by using different methods namely DPPH radical scavenging assay, ferric reducing assay, nitric oxide radical scavenging assay, superoxide radical scavenging assay and ABTS radical scavenging assay, and its IC50 values were found to be 110.85, 193.47, 109.06, 88.69 and 12.56 ìg/ml for aqueous extract and 59.63, 242.71, 103.21, 84.95 and 4.21 ìg/ml respectively. The extracts exhibited marked dose dependent in vitro antioxidant activity. Secondary metabolite isolation and characterization and in vivo evaluation of aqueous and ethanolic extracts were under progress
New vector-scalar contributions to neutrinoless double beta decay and constraints on R-parity violation
We show that in minimal supersymmetric standard model (MSSM) with R-parity
breaking as well as in the left-right symmetric model, there are new observable
contributions to neutrinoless double beta decay arising from hitherto
overlooked diagrams involving the exchange of one W boson and one scalar boson.
In particular, in the case of MSSM, the present experimental bounds on
neutrinoless double beta decay lifetime improves the limits on certain R-parity
violating couplings by about two orders of magnitude. It is shown that similar
diagrams also lead to enhanced rates for conversion in
nuclei, which are in the range accessible to ongoing experiments.Comment: Latex file; 9 pages; 3 figures available on reques
An institutional evaluation of radiotherapy with concurrent and adjuvant temozolomide exclusively in grade III gliomas
Background: Gliomas are the most common tumors that develop from glial cells in the brain. As per WHO classification, grade III (high-grade) gliomas are usually treated by surgery followed by radiotherapy. Concurrent and adjuvant chemotherapy with temozolomide (TMZ) is showing new hope in the management.Methods: Prospective study was conducted in 20 WHO grade III glioma patients at GSL medical college and general hospital for a period of 2 years (August 2019 to July 2021) to evaluate the role of concurrent and adjuvant TMZ with radiation in the treatment of grade III gliomas. The primary objectives of the study were to determine toxicity and response rates in our set of patients. The secondary objectives were to determine progression-free survival and overall survival.Results: Majority were males (80%) in the age group of 30 to 49 (75%). 40% of gliomas were in the temporal lobe. Headache was the most presenting symptom (60%) followed by seizures (35%).70 to 80 Karnofsky performance status/ KPS score was seen in 70% of cases. None of the patients in the study had grade 3 or 4 toxicities. 40% had a complete response according to MacDonald’s criteria. At a median follow-up of 10 months, 25% of patients had disease progression and 1yr overall survival was 95%.Conclusions: TMZ combined with radiation was well tolerated in our set of patients with grade III gliomas without any significant toxicity
RP-HPLC (STABILITY-INDICATING) BASED ASSAY METHOD FOR THE SIMULTANEOUS ESTIMATION OF DORAVIRINE, TENOFOVIR DISOPROXIL FUMARATE AND LAMIVUDINE
Objective: In this study, a RP-HPLC (stability-indicating) based assay method for the estimation of doravirine (DRV), tenofovir disoproxil fumarate (TFF) and lamivudine (LMV) simultaneously in the tablets was described.
Methods: The simultaneous analysis of DRV, TFF and LMV was done with HPLC system (Agilent 1100 series) and Luna Phenomenex C18 (250 mm × 4.6 mm × 5 μ) column with isocratic mobile phase (35% volume ratio of methanol and 65% volume ratio of 20 mmol ammonium formate, pH 5). Validation of assay method was done on sensitivity, linearity, accuracy, selectivity, precision, robustness and specificity.
Results: The calibration curves were linear through the range of 25-200 µg/ml for DRV and 75-600 µg/ml for TFF and LMV. The percent relative standard deviation for intraday variation/precision, interday variation/precision, intermediate precision/ruggedness and robustness were lower than 2%. The recovery of LMV (99.09-99.76%), TFF (99.10-99.41%) and DRV (98.65-99.28%) confirmed the good accuracy. The stability of LMV, TFF and DRV in 0.1N NaOH, 3% peroxide, 0.1 N HCl, UV light and dry heat of 60 °C was determined.
Conclusion: The results have allowed the method to be implemented in the tablets to quantify DRV, TFF, and LMV
Effect of Liquefaction Induced Lateral Spreading on Seismic Performance of Pile Foundations
Seismically active areas are vulnerable to liquefaction, and the influence of liquefaction on pile foundations is very severe. Study of pile-supported buildings in liquefiable soils requires consideration of soil-pile interaction and evaluation of the interaction resulting from movement of soil surrounding the pile. This paper presents the results of three-dimensional finite difference analyses conducted to understand the effect of liquefiable soils on the seismic performance of piles and pile groups embedded in stratified soil deposits using the numerical tool FLAC3D. A comparative study has been conducted on the performance of pile foundations on level ground and sloping ground. The soil model consists of a non-liquefiable, slightly cemented sand layer at the top and bottom and a liquefiable Nevada sand layer in between. This stratified ground is subjected to 1940 El Centro, 2001 Bhuj (India) earthquake ground motions, and harmonic motion of 0.3g acceleration. Parametric studies have been carried out by changing the ground slope from 0° to 10° to understand the effects of sloping ground on pile group response. The results indicate that the maximum bending moments occur at boundaries between liquefiable and non-liquefiable layers, and that the bending moment increases with an increase in slope angle. The presence of a pile cap prevents horizontal ground displacements at ground level. Further, it is also observed that the displacements of pile groups under sloping ground are in excess of those on level ground due to lateral spreading. Doi: 10.28991/CEJ-SP2021-07-05 Full Text: PD
Lepton Flavor Violation and the Origin of the Seesaw Mechanism
The right--handed neutrino mass matrix that is central to the understanding
of small neutrino masses via the seesaw mechanism can arise either (i) from
renormalizable operators or (ii) from nonrenormalizable or super-renormalizable
operators, depending on the symmetries and the Higgs content of the theory
beyond the Standard Model. In this paper, we study lepton flavor violating
(LFV) effects in the first class of seesaw models wherein the \nu_R Majorana
masses arise from renormalizable Yukawa couplings involving a B-L = 2 Higgs
field. We present detailed predictions for \tau -> \mu + \gamma and \mu -> e +
\gamma branching ratios in these models taking the current neutrino oscillation
data into account. Focusing on minimal supergravity models, we find that for a
large range of MSSM parameters suggested by the relic abundance of neutralino
dark matter and that is consistent with Higgs boson mass and other constraints,
these radiative decays are in the range accessible to planned experiments. We
compare these predictions with lepton flavor violation in the second class of
models arising entirely from the Dirac Yukawa couplings. We study the
dependence of the ratio r \equiv B(\mu -> e+\gamma)/B(\tau ->\mu +\gamma) on
the MSSM parameters and show that measurement of r can provide crucial insight
into the origin of the seesaw mechanism.Comment: 20 pages, Revtex, 7 figure
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