Seed fertility in tetraploid grapes and their crosses with diploids

The fruit and seed set as well as the occurrence of empty seeds in diploids, tetraploids and their crosses in five varieties of grapes were studied. Ovule lengths at certain intervals after anthesis in the diploid and tetraploid of one variety have been presented to indicate development of ovules. Late abortions of ovules resulting in empty seededness in tetraploids were found to be related to the shortening of period II of berry growth, earlier and greater accumulation of TSS, the earlier onset of period III and the higher rate of growth of the ovary. The consequent lack of adjustment between the pace of growth of endosperm and the ovary probably led to somatoplasitc sterility

Search for dilepton signatures from minimal low-energy supergravity in pp̅ collisions at √s=1.8 TeV

We report on a search for supersymmetry using the D∅ detector. The 1994-1996 data sample of √s=1.8 TeV pp̅ collisions was analyzed for events containing two leptons (e or μ), two or more jets, and missing transverse energy. Assuming the minimal supergravity model, with A0=0 and μ<0, various thresholds were employed to optimize the search. No events were found beyond expectation from the background. We set a lower limit at the 95% C.L. of 255 GeV/c2 for equal mass squarks and gluinos for tanβ=2, and present exclusion contours in the (m0,m½) plane for tanβ=2-6

Prospects for Oyster Culture in Kerala Backwaters

The oysters are highly esteemed sea foods in Japan, U.S.A. and Europe. It is stated that as early as the first century B.C., the Romans practised simple method of oyster culture by collecting oyster seed and growing them for food. In the world aquaculture production of 1,53,22,703 t in 1990, the molluscs accounted for 29,65.265 t forming 19.35%

Measurement of the high-mass drell-yan cross section and limits on quark-electron compositeness scales

We present a measurement of the Drell-Yan cross section at high dielectron invariant mass using 120pb-1 of data collected in pp̅ collisions at √s=1.8TeV by the D0 Collaboration during 1992-1996. No deviation from standard model expectations is observed. We use the data to set limits on the quark-electron compositeness scale. The 95% confidence level lower limits on the compositeness scale vary between 3.3 and 6.1 TeV depending on the assumed form of the effective contact interaction

Measurement of the W boson mass

We present a measurement of the W boson mass using data collected by the D0 experiment at the Fermilab Tevatron during 1994-1995. We identify W bosons by their decays to eν final states. We extract the W mass MW by fitting the transverse mass and transverse electron momentum spectra from a sample of 28323 W→eν decay candidates. We use a sample of 3563 dielectron events, mostly due to Z→ee decays, to constrain our model of the detector response. From the transverse mass fit we measure MW=80.44±0.10(stat)±0.07(syst) GeV. Combining this with our previously published result from data taken in 1992-1993, we obtain MW=80.43±0.11GeV

Experimental search for chargino and neutralino production in supersymmetry models with a light gravitino

We search for inclusive high ET diphoton events with large missing transverse energy in pp̅ collisions at √s=1.8 TeV. Such events are expected from pair production of charginos and neutralinos within the framework of the minimal supersymmetric standard model with a light gravitino. No excess of events is observed. In that model, and assuming gaugino mass unification at the GUT scale, we obtain a 95% C.L. exclusion region in the supersymmetry parameter space and lower mass bounds of 150 GeV/c2 for the lightest chargino and 77 GeV/c2 for the lightest neutralino

Saltwater pearl fisheries and pearl culture in India: An update

Recently. C. Ricbard Fassler (1991 a, 1991 b, 1992) gave an overview of pearl culture in the world and discussed both "opportunities and obstacles" for the development of pearl culture. While Japan still bolds the monopoly, China is fast catching up and several countries are producing pearls on commercial lines, mostly with Japanese collaboration, the notable being Australia, Frencb Polynesia, Indonesia, New Caledonia and Cook Islands, Fassler (1991 a) stated that thougb the Indians bave developed their own pearl industry, there is little publisbed information

Search for first-generation scalar and vector leptoquarks

We describe a search for the pair production of first-generation scalar and vector leptoquarks in the eejj and eνjj channels by the DØ Collaboration. The data are from the 1992–1996 pp̅ run at √s=1.8 TeV at the Fermilab Tevatron collider. We find no evidence for leptoquark production; in addition, no kinematically interesting events are observed using relaxed selection criteria. The results from the eejj and eνjj channels are combined with those from a previous DØ analysis of the ννjj channel to obtain 95% confidence level (C.L.) upper limits on the leptoquark pair-production cross section as a function of mass and of β, the branching fraction to a charged lepton. These limits are compared to next-to-leading-order theory to set 95% C.L. lower limits on the mass of a first-generation scalar leptoquark of 225, 204, and 79 GeV/c2 for β=1, 1/2, and 0, respectively. For vector leptoquarks with gauge (Yang-Mills) couplings, 95% C.L. lower limits of 345, 337, and 206 GeV/c2 are set on the mass for β=1, 1/2, and 0, respectively. Mass limits for vector leptoquarks are also set for anomalous vector couplings

Experimental culture of the Indian oyster, Crassostrea madrasensis (Preston) at Ashtamudi lake, Kerala

The edible oyster, Crassostrea Madrasensis, (P reston) occurs attached to hard substrates in the intertidal and subtidal regions of the coastal areas. Oyster meat is a highly esteemed seafood and aquaculture of oysters is widely prevalent and well established in many temperate countri