1,658 research outputs found

    Modelling the kinetics of elements release from a zeolitic-rich tuff

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    The present investigation aims at modeling the kinetics of elements (Fe, Mg, K, Ca, Na, Al, and Si) release from zeolitic-rich Phlegraean Yellow Tuff weathered by tannic acid solutions at different concentration. Three equations were tested—power function, the Weber–Morris model, and the Elovich equation. Power function was revealed to be an excellent empirical equation well fitted to the experimental data. Its numerical parameters were suitable predictive tools, highlighting both the intensity and modality of weathering processes. By paralleling the dissolution rates, it was possible to allow rock-sources from which elements were released during three distinct weathering stages—(i) the first stage was dominated by biotite and amorphous weathering, (ii) the second stage also started with the breakdown of zeolite framework; and (iii) in the third stage, the whole of weathering/release process approached a steady state. Finally, these outcomes may be used to forecast the pedogenic/nutritional potential of zeolitic-rich tuffs as pedotechnical matrices in restoration design

    Signal-to-Noise Eigenmode Analysis of the Two-Year COBE Maps

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    To test a theory of cosmic microwave background fluctuations, it is natural to expand an anisotropy map in an uncorrelated basis of linear combinations of pixel amplitudes --- statistically-independent for both the noise and the signal. These S/NS/N-eigenmodes are indispensible for rapid Bayesian analyses of anisotropy experiments, applied here to the recently-released two-year COBE {\it dmr} maps and the {\it firs} map. A 2-parameter model with an overall band-power and a spectral tilt νΔT\nu_{\Delta T} describes well inflation-based theories. The band-powers for {\it all} the {\it dmr} 53,90,3153,90,31 aa+bb GHz and {\it firs} 170 GHz maps agree, {(1.1±0.1)×105}1/2\{(1.1\pm 0.1)\times 10^{-5}\}^{1/2}, and are largely independent of tilt and degree of (sharp) S/NS/N-filtering. Further, after optimal S/NS/N-filtering, the {\it dmr} maps reveal the same tilt-independent large scale features and correlation function. The unfiltered {\it dmr} 5353 aa+bb index νΔT+1\nu_{\Delta T}+1 is 1.4±0.41.4\pm 0.4; increasing the S/NS/N-filtering gives a broad region at (1.0--1.2)±\pm0.5, a jump to (1.4--1.6)±\pm0.5, then a drop to 0.8, the higher values clearly seen to be driven by S/NS/N-power spectrum data points that do not fit single-tilt models. These indices are nicely compatible with inflation values (\sim0.8--1.2), but not overwhelmingly so.Comment: submitted to Phys.Rev.Letters, 4 pages, uuencoded compressed PostScript; also bdmr2.ps.Z, via anonymous ftp to ftp.cita.utoronto.ca, cd to /pub/dick/yukawa; CITA-94-2

    Marine Fisheries Policy Brief-1 സമുദ്ര മത്സ്യമേഖലാ നയ പരിപ്രേക്‌ഷ്യം - 1 കേരളം (Marine Fisheries Policy Brief-1 Kerala Malayalam version)

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    Marine Fisheries Policy Brief-1 സമുദ്ര മത്സ്യമേഖലാ നയ പരിപ്രേക്‌ഷ്യം - 1 കേരളം (Marine Fisheries Policy Brief-1 Kerala Malayalam version

    Marine Fisheries Policy Brief-1 Kerala

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    Kerala which has a coastline of 590 km ranks first in marine fish production of India, contributing nearly 25% (5.81 lakh tonnes on average) to the total annual production. The export of marine products from the State earns valuable foreign exchange besides affording innumerable job opportunities in the industry. The population depending on fisheries has steadily increased over the years and stood at 6,02,234 in 2005 (Anon., 2005). Kerala has been in the forefront of absorbing innovative and new technologies in fishing practices, which have led the marine fisheries sector to take a complex structure. The 1980s was an important period in the development of marine fisheries in Kerala. In the first half of the period the motorized sector grew rapidly and became the most important sector yielding the maximum catch in 1988. By that time, ringseine became very popular in exploiting the pelagic resources and replaced the boatseines to a very great extent. Huge size of the new net (450 to 1000 m long) and large number of crew (30 to 50) needed for its operation necessitated larger boats with high capacity outboard engines (3 outboard engines of 40 hp each). This facilitated extension of fishing grounds for the motorized sector. The fishing grounds covered by the mechanised sector also extended by increasing the boat size and fishing effort and efficiency through multi-day fishing during the late 90s

    Synthesis, structures and reduction chemistry of monophthalocyanine scandium hydroxides

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    The preparation and structural characterization of a pair of scanditun(III) phthalocyanine hydroxide complexes were achieved by reaction of PcScCl with alkali metal alkoxides, likely via hydrolysis of soluble PcSc-alkoxide intermediates. A Sc2Li2 (mu(3)-OH)(4) cubane supported by two distorted Pc rings of the form (PcSc)(2)(mu(3)-OH)(4)Li-2 (THF)(DME) was isolated from the reaction of PcScCl with (LiOPr)-Pr-i, while a simpler alkali-metal-free [Pc2Sc2(mu(2)-OH)(2)(THE)] was obtained from addition of (NaOBu)-Bu-i; both structures are reminiscent of bent metallocenes, with dihedral angles between the two Pc rings of 50.8 and 37.7 degrees respectively. A soluble PcScOH material can also be obtained directly via hydrolysis of insoluble PcScCl in approximately 95:5 THF:water. Reduction of the Pc ring of PcScCl using KC8 is reversible and generates Pc3- and Pc4--containing materials that were characterized via UV-vis spectroscopy and, where appropriate EPR and H-1 NMR spectroscopy; analogous reductions of the PcScOH-based species were irreversible. Exposure of the air-sensitive, reduced PcScCl-based species to ambient atmosphere generated PcScOH materials analogous to the direct hydrolysis route

    Economic valuation of net social benefit of seasonal fishing ban in selected maritime states of India

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    Seasonal fishing ban (SFB) is followed along the Indian coast for the past 15 to 25 years for sustaining marine fishery resources. However, the effect of the SFB on fishery resources and societies has not yet been established. In this paper, an attempt has been made to evaluate the net social benefit of the SFB which will help to throw light on the impact of SFB and guide to substantiate or recommend alternate/improved management measures to sustain marine fisheries. In the present study, the economic valuation of SFB was carried out in five selected maritime states of the country. It was found that the incremental biomass ranged from 5 to 9%. The net social benefit was also positive in all the states, which ranged from `1,097 lakhs in Andhra Pradesh to `2,796 lakhs in Tamil Nadu. Based on performance of SFB in terms of net societal benefits, the states were ranked in the order, Tamil Nadu, Kerala, Gujarat, Karnataka followed by Andhra Pradesh. Results of the study recommends continuation of SFB, however, it should not be considered as a stand-alone practice and should be considered only as part of a bundle of management measures for sustaining marine fisheries in India

    The bane of juvenile fish catches

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    Juvenile fishes are defined as immature fishes that have not yet had the opportunity to replenish the fish population by spawning. The length at which 50% of the fishes of any particular species mature varies among species and is called its Length at First Maturity (Lm). When juveniles are caught in large numbers there is an economic loss as fishermen get very low prices for the small sized young fish as compared to the larger adults

    Python I, II, and III CMB Anisotropy Measurement Constraints on Open and Flat-Lambda CDM Cosmogonies

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    We use Python I, II, and III cosmic microwave background anisotropy data to constrain cosmogonies. We account for the Python beamwidth and calibration uncertainties. We consider open and spatially-flat-Lambda cold dark matter cosmogonies, with nonrelativistic-mass density parameter Omega_0 in the range 0.1--1, baryonic-mass density parameter Omega_B in the range (0.005--0.029) h^{-2}, and age of the universe t_0 in the range (10--20) Gyr. Marginalizing over all parameters but Omega_0, the combined Python data favors an open (spatially-flat-Lambda) model with Omega_0 simeq 0.2 (0.1). At the 2 sigma confidence level model normalizations deduced from the combined Python data are mostly consistent with those drawn from the DMR, UCSB South Pole 1994, ARGO, MAX 4 and 5, White Dish, and SuZIE data sets.Comment: 20 pages, 7 figures, accepted by Ap

    किशोर मछली पकड़ का अभिशाप (The bane of juvenile fish catches)

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    Juvenile fishes are defined as immature fishes that have not yet had the opportunity to replenish the fish population by spawning. The length at which 50% of the fishes of any particular species mature varies among species and is called its Length at First Maturity (Lm). When juveniles are caught in large numbers there is an economic loss as fishermen get very low prices for the small sized young fish as compared to the larger adults
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