436 research outputs found

    Vizhinjam Marine Aquarium Haven for Marine Ornamentals

    Get PDF
    There has been a huge growth of public aquaria since the opening of the first public aquarium display in the Fish House at the London Zoo in t 826, and particularly in the past 20 years (Hall and Douglas 2003)

    Breeding and larval rearing of three species of damselfishes (family: Pomacentridae)

    Get PDF
    The annual world ornamental fish trade is to the tune of around 4.5 billion dollars (1995) with a growth rate of about 8%. Nearly 50% of the revenue from the trade is contributed by marine ornamental fishes. With the spread of scientific knowledge on marine aquarium management and development of an array of aquarium gadgets, there is an Increased demand for tropical marine aquarium fishes in recent years and this opens up the possibility of developing a lucrative marine ornamental fish trade the worldover

    Length-weight, length-length relationships and condition factor of obtuse barracuda Sphyraena obtusata Cuvier, 1829 (Pisces: Perciformes) from Vizhinjam coast, Kerala, India

    Get PDF
    Eleven morphometric variables including weight were recorded for 429 specimens of obtuse barracuda Sphyraena obtusata Cuvier, 1829 collected over a period of two years from January 2017 to December 2018, from Vizhinjam fish landing centre, Thiruvananthapuram, Kerala. Length-weight relationship and length-length relationship of the species were estimated using linear regression analysis. Different length measurements were converted to ratios with standard length as morphometric ratios and the growth rate was assessed gender wise. Length-weight relationship for male and female population were estimated as Wm= 13.326 × L3.2409 and Wf = 11.952 × L2.9821, respectively. Linear relationships for other morphometric variables and morphometric ratios with standard length were established for the species. Principal component analysis was performed and total length, snout length and snout to pre-nostril length were identified as key morphometric variables discriminating gender. The relative condition factor was estimated as 1.04+0.13 for total population and the role of morphometric ratios in sex differentiation was examined

    Search for electron antineutrino interactions with the Borexino Counting Test Facility at Gran Sasso

    Full text link
    Electron antineutrino interactions above the inverse beta decay energy of protons (E_\bar{\nu}_e>1.8) where looked for with the Borexino Counting Test Facility (CTF). One candidate event survived after rejection of background, which included muon-induced neutrons and random coincidences. An upper limit on the solar νˉe\bar{\nu}_{e} flux, assumed having the 8^8B solar neutrino energy spectrum, of 1.1×105\times10^{5} cm2^{-2}~s1^{-1} (90% C.L.) was set with a 7.8 ton ×\times year exposure. This upper limit corresponds to a solar neutrino transition probability, νeνˉe\nu_{e} \to \bar{\nu}_{e}, of 0.02 (90% C.L.). Predictions for antineutrino detection with Borexino, including geoneutrinos, are discussed on the basis of background measurements performed with the CTF.Comment: 10 pages, 9 figures, 5 table

    Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun

    Full text link
    The Sun is fueled by a series of nuclear reactions that produce the energy that makes it shine. The primary reaction is the fusion of two protons into a deuteron, a positron and a neutrino. These neutrinos constitute the vast majority of neutrinos reaching Earth, providing us with key information about what goes on at the core of our star. Several experiments have now confirmed the observation of neutrino oscillations by detecting neutrinos from secondary nuclear processes in the Sun; this is the first direct spectral measurement of the neutrinos from the keystone proton-proton fusion. This observation is a crucial step towards the completion of the spectroscopy of pp-chain neutrinos, as well as further validation of the LMA-MSW model of neutrino oscillations.Comment: Proceedings from NOW (Neutrino Oscillation Workshop) 201

    Final results of Borexino Phase-I on low energy solar neutrino spectroscopy

    Full text link
    Borexino has been running since May 2007 at the LNGS with the primary goal of detecting solar neutrinos. The detector, a large, unsegmented liquid scintillator calorimeter characterized by unprecedented low levels of intrinsic radioactivity, is optimized for the study of the lower energy part of the spectrum. During the Phase-I (2007-2010) Borexino first detected and then precisely measured the flux of the 7Be solar neutrinos, ruled out any significant day-night asymmetry of their interaction rate, made the first direct observation of the pep neutrinos, and set the tightest upper limit on the flux of CNO neutrinos. In this paper we discuss the signal signature and provide a comprehensive description of the backgrounds, quantify their event rates, describe the methods for their identification, selection or subtraction, and describe data analysis. Key features are an extensive in situ calibration program using radioactive sources, the detailed modeling of the detector response, the ability to define an innermost fiducial volume with extremely low background via software cuts, and the excellent pulse-shape discrimination capability of the scintillator that allows particle identification. We report a measurement of the annual modulation of the 7 Be neutrino interaction rate. The period, the amplitude, and the phase of the observed modulation are consistent with the solar origin of these events, and the absence of their annual modulation is rejected with higher than 99% C.L. The physics implications of phase-I results in the context of the neutrino oscillation physics and solar models are presented

    Recent Borexino results and prospects for the near future

    Full text link
    The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material.Comment: 8 pages, 11 figures. To be published as proceedings of Rencontres de Moriond EW 201

    Measurement of CNGS muon neutrino speed with Borexino

    Get PDF
    We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between a =17 GeV muon neutrino and a particle moving at the speed of light in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with zero.Comment: 6 pages, 5 figure
    corecore