1,388 research outputs found
Effects of Decays of Tau Neutrinos Near A Supernova
We revisit the constraints implied by SN 1987 A observations on the decay
rate of a multi-MeV decaying into the visible channel , if its lifetime is more than 10 {\it sec.}. We
discuss its implication for the minimal left-right symmetric model with see-saw
mechanism for neutrino masses. We also speculate on the possible formation of a
``giant Capacitor" in intergalactic space due to the decay of "neutronization"
's and spin allignment possibility in the supernova.Comment: 29 Pages, Tex file, UMDHEP 94-4
Kerr-Schild type initial data for black holes with angular momenta
Generalizing previous work we propose how to superpose spinning black holes
in a Kerr-Schild initial slice. This superposition satisfies several physically
meaningful limits, including the close and the far ones. Further we consider
the close limit of two black holes with opposite angular momenta and explicitly
solve the constraint equations in this case. Evolving the resulting initial
data with a linear code, we compute the radiated energy as a function of the
masses and the angular momenta of the black holes.Comment: 13 pages, 3 figures. Revised version. To appear in Classical and
Quantum Gravit
Long gamma-ray bursts without visible supernovae: a case study of redshift estimators and alleged novel objects
It has been argued that the observational limits on a supernova (SN)
associated with GRB060614 convincingly exclude a SN akin to SN1998bw as its
originator, and provide evidence for a new class of long-duration GRBs. We
discuss this issue in the contexts of indirect 'redshift estimators' and of the
fireball and cannonball models of GRBs. The latter explains the unusual
properties of GRB060614: at its debated but favoured low redshift (0.125) they
are predicted, as opposed to exceptional, if the associated core-collapse SN is
of a recently discovered, very faint type. We take the occasion to discuss the
'association' between GRBs and SNe.Comment: 19 pages, 2 figures. To be published in Ap
Effect of Pre-harvest Application of Calcium Chloride and Gibberellic Acid on Shelf-Life and Post-Harvest Quality of Apricot (Prunus armeniaca L.) Cv. Harcot
Pre-harvest application of calcium chloride (0.5, 1.0, and 1.5 %) and gibberellic acid(10, 20 and 30 ppm) at 80% blooming, fruit-set and at 15 days before harvest were carried out on 5-year old trees of apricot cv. Harcot. All the treatments significantly reduced physiological loss in fruit weight, fruit diameter and spoilage percentage during storage. However, CaCl2 @ 1.5% was found to be most effective in minimizing weight loss in fruits during storage compared to Control. Fruits quality (TSS, titrable acidity, TSS/TA, ascorbic acid, total sugar, etc.) was also found to be better (even at 8 days of storage at ambient condition with this treatment) compared to Control. Hence, it can be concluded that pre-harvest foliar application in apricot cv. Harcot with CaCl2 @ 1.5% at three stages, i.e., 80% blooming, at fruit-set and 15 days before harvest, enhances shelf-life of the fruit from 3-5 days storage to 8 days storage, and can maintain good fruit quality under ambient storage-condition for up to 8 days
Gene action studies in early maturing maize (Zea mays L.) inbred lines
The present investigation was aimed to investigate the gene action in early maturing maize (Zea mays L.) inbred lines. The experimental material comprised of 30 crosses generated by crossing six maize inbred lines in a diallel mating design during Kharif 2013. These 30 crosses along with standard checks viz., SMH-2 and VMH-45 were evaluated in randomized block design in three replications during Kharif 2014 and Kharif 2015. Significant variation was observed for all studied traits during both the seasons. Both additive (D) and dominance (H1 and H2) components of genetic variance were found significant under the study. Preponderance of non-additive gene action was observed for all traits under study. Average degree of dominance was in over dominance range for all characters. The gene distribution was asymmetrical for all traits. The value of KD / KR indicated presence of excess of dominant genes for all traits except 100-grain weight and ear girth. Heritability of most of the traits was low to medium
Economic loss assessment on juvenile fish catch due to forced non-selectivity in a selective fishing gear, gillnet along Mumbai coast, India
A study on quantity and value of juvenile fish landings was carried out in the gillnet fishery of three selected landing centers along Mumbai coast viz., Versova, Cuff Parade and Mahim in India using Out board motors (OBM), Inboard motors (IBM) and non-motorised gillnetters respectively. The data on the quantity and value of landed juveniles were collected and analysed to reach a consensus on the gross economic loss on account of juvenile fishing. A bio-economic model was used to estimate economic loss due to juvenile fishing of 18 commercially important species of finfish and shellfish. A huge economic loss was recorded due to fishing of juveniles of 18 species by three different gillnet sectors. The analysis indicated that IBM gillnetters at Cuff Parade incurred maximum loss of Rs. 62.26 crores with major contribution from juveniles of seerfish followed by non-motorised gillnetter (Rs.29.98 crores) at Mahim and 25.33 crores in OBM gillnetters at Versova
Sources of UHECRs in view of the TUS and JEM-EUSO experiments
The origin of ultra-high-energy cosmic rays (UHECRs) is one of the most
intriguing problems of modern cosmic ray physics. We briefly review the main
astrophysical models of their origin and the forthcoming orbital experiments
TUS and JEM-EUSO, and discuss how the new data can help one solve the
long-standing puzzle.Comment: 4 pages; prepared for ECRS-2012 (http://ecrs2012.sinp.msu.ru/); v2: a
reference adde
How many sigmas is the solar neutrino effect?
The minimal standard electroweak model can be tested by allowing all the
solar neutrino fluxes, with undistorted energy spectra, to be free parameters
in fitting the measured solar neutrino event rates, subject only to the
condition that the total observed luminosity of the sun is produced by nuclear
fusion. The rates of the five experiments prior to SNO (chlorine, Kamiokande,
SAGE, GALLEX, Super-Kamiokande) cannot be fit by an arbitrary choice of
undistorted neutrino fluxes at the level of 2.5 sigma (formally 99% C.L.).
Considering just SNO and Super-Kamiokande, the discrepancy is at the 3.3 sigma
level(10^{-3} C.L.). If all six experiments are fit simultaneously, the formal
discrepancy increases to 4 sigma (7*10^{-5} C.L.). If the relative scaling in
temperature of the nuclear reactions that produce 7Be and 8B neutrinos is taken
into account, the formal discrepancy is at the 7.4 sigma level.Comment: 1 figure; related information at http://www.sns.ias.edu/~jn
The luminosity constraint on solar neutrino fluxes
A specific linear combination of the total solar neutrino fluxes must equal
the measured solar photon luminosity if nuclear fusion reactions among light
elements are responsible for solar energy generation. This luminosity
constraint, previously used in a limited form in testing the no neutrino
oscillation hypothesis, is derived in a generality that includes all of the
relevant solar neutrino fluxes and which is suitable for analyzing the results
of many different solar neutrino experiments. With or without allowing for
neutrino oscillations, the generalized luminosity constraint can be used in
future analyses of solar neutrino data. Accurate numerical values for the
linear coefficients are provided.Comment: related material at http://www.sns.ias.edu/~jn
Nuclear Reaction Rates in a Plasma
The problem of determining the effects of the surrounding plasma on nuclear
reaction rates in stars is formulated ab initio, using the techniques of
quantum statistical mechanics. We derive a result that expresses the complete
effects of Coulomb barrier penetration and of the influence of the surrounding
plasma in terms of matrix elements of well defined operators. We find that
possible "dynamical screening" effects that have been discussed in the
literature are absent. The form of our results suggests that an approach that
relies on numerical calculations of the correlation functions in a classical
Coulomb gas, followed by construction of an effective two body potential and a
quantum barrier penetration calculation, will miss physics that is as important
as the physics that it includes.Comment: 66 pages, revtex, Errors Fixed, Explanation Adde
- …