694 research outputs found

    Science and technology in agricultural development - a key to the future

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    Genetic studies on mote index, pollen sterility and earliness in interspecific cotton hybrids

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    Hybrids between four divergent varieties of Gossypium hirsutum and eight of G. barbadense were evaluated for three components of commercial importance, mote index, pollen sterility and earliness in their F1 generation. It was found that the former two components were predominantly under the control of additive gene action. The studies brought out the possibilities of selecting for fertile and early-maturing hybrids with the incidence of motes. American Nectariless, K 3400 SB 289 E, SB 1095-6 were found to be desirable parents and the crosses of the former two as female with the letter two as male parents were found to possess all the desirable character

    Studies on Cobalt(III) Metallosurfactants. Kinetics and Mechanism of Reduction of Cobalt(III) by Iron(II) in Aqueous Acid Medium

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    The kinetics and mechanism of reduction of the surfactant complex ions, cis-chloro/bromo(dodecylamine)(triethylenetetramine)cobalt(III) by iron(II) in aqueous solution were studied at 303, 308 and 313 K by spectrophotometry under pseudo-first-order conditions using an excess of the reductant. The second-order rate constant increases with cobalt(III) concentration and the presence of aggregation of the complex itself alters the reaction rate. The reductions are acid-independent in the range [H+] = 0.05-0.25mol dm−3. Variation of ionic strength (μ) influences the reaction rate. Activation and thermodynamic parameters have been computed. It is suggested that the reaction of Fe2+(aq) with the cobalt(III) complex proceeds by an inner-sphere mechanism. The critical micelle concentration (CMC) values of these surfactant metal complexes in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308 and 313 K) served for the evaluation of the temperature-dependent CMC and the standard Gibbs energy of micellization (ΔGm0

    Heterotic potential of single crosses in groundnut (Arachis hypogaea L.)

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    Two sets of diallel crosses involving diverse parents were evaluated for heterosis and combing ability for 15 characters measured at seedling, flowering, and harvest phases. The utility of Spanish x Spanish, Valencia x Valencia, Virginia Bunch x Virginia Bunch and Virginia Runner x Virginia Runner crosses along with the infra-specific ones in breeding programs is emphasized. A high range of heterosis was shown by a few crosses. Parents of the diallels were classified as High (H) or Low (L) on the basis of their gca over the 15 characters spanning the entire growth phase of the plant. It was suggested that the heterotic potential of H x L crosses could be successfully exploited to create a broader genetic base

    Benefit-based consumer segmentation and performance evaluation of clustering approaches: An evidence of data-driven decision-making

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    This study evaluates the performance of different data clustering approaches for searching the profitable consumer segments in the UK hospitality industry. The paper focuses on three aspects of datasets including the ordinal nature of data, high dimensionality and outliers. Data collected from 513 sample points are analysed in this paper using four clustering approaches: Hierarchical clustering, K-Medoids, fuzzy clustering, and Self-Organising Maps (SOM). The findings suggest that Fuzzy and SOM based clustering techniques are comparatively more efficient than traditional approaches in revealing the hidden structure in the data set. The segments derived from SOM has more capability to provide interesting insights for data-driven decision making in practice. This study makes a significant contribution to literature by comparing different clustering approaches and addressing misconceptions of using these for market segmentation to support data-driven decision making in business practices

    {Improved Bounds on Fourier Entropy and Min-entropy}

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    Given a Boolean function f:{1,1}n{1,1}f:\{-1,1\}^n\to \{-1,1\}, the Fourier distribution assigns probability f^(S)2\widehat{f}(S)^2 to S[n]S\subseteq [n]. The Fourier Entropy-Influence (FEI) conjecture of Friedgut and Kalai asks if there exist a universal constant C>0 such that H(f^2)CInf(f)H(\hat{f}^2)\leq C Inf(f), where H(f^2)H(\hat{f}^2) is the Shannon entropy of the Fourier distribution of ff and Inf(f)Inf(f) is the total influence of ff. 1) We consider the weaker Fourier Min-entropy-Influence (FMEI) conjecture. This asks if H(f^2)CInf(f)H_{\infty}(\hat{f}^2)\leq C Inf(f), where H(f^2)H_{\infty}(\hat{f}^2) is the min-entropy of the Fourier distribution. We show H(f^2)2Cmin(f)H_{\infty}(\hat{f}^2)\leq 2C_{\min}^\oplus(f), where Cmin(f)C_{\min}^\oplus(f) is the minimum parity certificate complexity of ff. We also show that for every ϵ0\epsilon\geq 0, we have H(f^2)2log(f^1,ϵ/(1ϵ))H_{\infty}(\hat{f}^2)\leq 2\log (\|\hat{f}\|_{1,\epsilon}/(1-\epsilon)), where f^1,ϵ\|\hat{f}\|_{1,\epsilon} is the approximate spectral norm of ff. As a corollary, we verify the FMEI conjecture for the class of read-kk DNFDNFs (for constant kk). 2) We show that H(f^2)2aUC(f)H(\hat{f}^2)\leq 2 aUC^\oplus(f), where aUC(f)aUC^\oplus(f) is the average unambiguous parity certificate complexity of ff. This improves upon Chakraborty et al. An important consequence of the FEI conjecture is the long-standing Mansour's conjecture. We show that a weaker version of FEI already implies Mansour's conjecture: is H(f^2)Cmin{C0(f),C1(f)}H(\hat{f}^2)\leq C \min\{C^0(f),C^1(f)\}?, where C0(f),C1(f)C^0(f), C^1(f) are the 0- and 1-certificate complexities of ff, respectively. 3) We study what FEI implies about the structure of polynomials that 1/3-approximate a Boolean function. We pose a conjecture (which is implied by FEI): no "flat" degree-dd polynomial of sparsity 2ω(d)2^{\omega(d)} can 1/3-approximate a Boolean function. We prove this conjecture unconditionally for a particular class of polynomials

    A retrospective interventional study for evaluation of efficacy and safety of sildenafil citrate in improving intrauterine growth restriction and oligohydramnios using ultrasound Doppler velocimetry

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    Background: Intrauterine growth restriction (IUGR) is one of the major reasons for neonatal morbidity and mortality. Oligohydramnios is a common finding in IUGR. In majority of these cases diminished utero-placental blood flow is observed. However, in spite of this understanding and identification of high-risk patients, the management options are limited. Sildenafil citrate, a phosphodiesterase type-5 inhibitor improves utero-placental perfusion.Methods: We present a retrospective interventional study involving 50 adult pregnant women diagnosed with early-onset IUGR (n=38) and oligohydramnios (n=12). Vaginal sildenafil citrate 25 mg t.i.d. was started from the day of diagnosis till delivery. Primary efficacy endpoints included changes in Doppler parameters i.e., amniotic fluid index (AFI), uterine artery (UA)- pulsatility index (PI), resistance index (RI) and systolic diastolic ratio (S/D ratio). Secondary endpoints included live birth, birth weight, Apgar score at birth, neonatal survival to hospital discharge and adverse maternal side effects.Results: There was a statistically significant improvement in UA-PI, RI and S/D ratios (p<0.0001) in all cases. In oligohydramnios cases, treatment showed a statistical significant increase in AFI score (2.86±1.33 cm). The mean birth weight on delivery was 2200 gm with good Apgar scores. No major adverse effects were reported by women using sildenafil citrate vaginally.Conclusions: Sildenafil citrate, by increasing utero-placental perfusion, improves uterine artery Doppler patterns, AFI, fetal weight and overall better neonatal survival rates by reducing neonatal morbidity and mortality. Sildenafil citrate may hold a promising treatment strategy for management of IUGR and oligohydramnios

    Ecology of biofouling on Crassostrea madrasensis (Preston) (Mollusca:Bivalvia) in a tropical backwater

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    Ecology of biofouling on the edible estuarine oyster Crassostrea madrasensis (Preston) has been investigated in the Ashtamudi Backwater of the southwest coast of India. Fouling was highly conspicuous throughout the year and dominant groups included barnacles, serpulids, bryozoans and modiolids. Intensity of fouling varied from 73 to 179 % on living oyster valves and 65 to 172 % on dead valves with respective annual averages of 118 and 127%. Substrate selection and settlement of the different groups were mostly opportunistic. Barnacles were the most dominant, living and dead ones collectively contributing to about 26 % of fouling on living valves and 32 % on dead valves. Serpulid fouling was 22 % both on living and dead oyster valves, bryozoans 15 and 12%, modiolids 11 and 12% and the miscellaneous groups formed 27 and 20 % respectively. Availability of free settling space and fouling in relation to substrate size were also investigated. Total fouling was very intense on oysters of 25-35 cm2 size group. Impact of biofouling on oysters and certain earlier studies on the topic are discussed
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