861 research outputs found

    Increasing Maize Tolerance to Drought and Flood with Seed Coating Treatments

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    The lack of irrigation in regions prone to drought, and flooding due to high rainfall or lack of drainage affects seed viability and the subsequent germination and crop establishment. Seed treatment in the form of coatings shows promise as an effective method to preserve the viability of corn (Zea mays) seeds in drought and flood conditions. Chemical formulations may help improve the seed corn vigor under these stressed conditions. This study examined the efficacy of β-aminobutyric acid [BABA] and N-isopropylacrylamide [NIPA] in inducing drought resistance, as well as the ability of lanolin and linseed oil to provide flood tolerance for seed corn. Germination rates and linear shoot growth measurements were used as indications of seed vigor. Uniform coatings of the treatments were applied to untreated seed corn, and treated seed performance was compared to an uncoated control batch of seeds. Water imbibition, moisture, and temperature were manipulated to replicate drought, flood, and optimal growth conditions. The preliminary results of these experiments indicate that these coatings did not significantly increase the viability during short-terms of stressed conditions. At suboptimal temperatures, uncoated control seeds displayed significantly higher seed vigor and growth rates. Manipulation of coating thickness and/or testing at more intense stress levels may be necessary for coating treatments to exhibit positive effects on corn seed resistance to drought and flood

    Association of Intronic Single Nucleotide Polymorphism (SNP) of CALM 1 gene with Osteoarthritis of the Knee in Indian Population: A Case-control Study

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    Osteoarthritis knee is one of the most prevalent disorders in the Indian subcontinent. The wide prevalence and varying features makes it a disease of disguise. Multiple etiological factors have been described. The most recent is genetic contribution in the causation of the disease. This case control study was conducted in the Department of Orthopaedic Surgery, CSM Medical University, Lucknow in collaboration with IIT, Kanpur. 120 cases and 120 controls were enrolled. Clinico-radiological features were noted and symptomatic clinical scoring was done. Genetic polymorphism in relation to intronic region of CALM 1 gene was studied by DNA extraction, Polymerase chain reaction (PCR) and Restriction fragment length polymorphism (RFLP) method. Statistical analysis was done using Stata software. There was no significant difference between age, sex and BMI among cases and controls (p value > .05). ESR (p value =0.0000), fasting blood sugar (p value= 0.0004) and serum uric acid (p value=0.0001) were significantly different among cases and controls. SNP was found in significantly higher number in cases than controls (p value = .0022). Heterozygosity was found only in 5 cases. Logistic regression has also proved significant association of occurrence of Single Nucleotide Polymorphism (SNP) with disease. CALM-1 gene intronic SNP (rs3213718) is present in Indian population. Occurrence of this SNP is significantly affecting the disease

    Discovery of Two New Faint Cataclysmic Variables

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    We report on the discovery of two new faint cataclysmic variables. The objects were selected as candidates from two different imaging surveys aimed at the discovery of such faint systems. One survey used color and variability while the other used color and Hα_\alpha emission as selection criteria. We present our spectra of the two new variables and discuss their properties. A discussion of the implication of these discoveries on the space density of faint cataclysmic variables is presented.Comment: 4 pages, 4 figures. Accepted to A&A letter

    Polarised radio pulsations from a new T dwarf binary

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    Brown dwarfs display Jupiter-like auroral phenomena such as magnetospheric Hα\alpha emission and coherent radio emission. Coherent radio emission is a probe of magnetospheric acceleration mechanisms and provides a direct measurement of the magnetic field strength at the emitter's location, both of which are difficult to access by other means. Observations of the coldest brown dwarfs (spectral types T and Y) are particularly interesting as their magnetospheric phenomena may be very similar to those in gas-giant exoplanets. Here we present 144 MHz radio and infrared adaptive optics observations of the brown dwarf WISEP J101905.63+652954.2 made using the LOFAR and Keck telescopes respectively. The radio data shows pulsed highly circularly polarised emission which yields a rotation rate of 0.32±0.030.32\pm0.03 hr1^{-1}. The infrared imaging reveals the source to be a binary with a projected separation of 423.0±1.6423.0\pm1.6 mas between components of spectral type T5.5±0.55\pm0.5 and T7.0±0.50\pm0.5. With a simple "toy model" we show that the radio emission can in principle be powered by the interaction between the two dwarfs with a mass-loss rates of at least 2525 times the Jovian value. WISEP J101905.63+652954.2 is interesting because it is the first pulsed methane dwarf detected in a low radio-frequency search. Unlike previous gigahertz-frequency searches that were only sensitive to objects with kiloGauss fields, our low-frequency search is sensitive to surface magnetic fields of 50\approx 50 Gauss and above which might reveal the coldest radio-loud objects down to planetary mass-scales.Comment: Accepted for publication in A&

    The Hawaii Infrared Parallax Program. VI. The Fundamental Properties of 1000+ Ultracool Dwarfs and Planetary-mass Objects Using Optical to Mid-IR SEDs and Comparison to BT-Settl and ATMO 2020 Model Atmospheres

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    We derive the bolometric luminosities (LbolL_{\mathrm{bol}}) of 865 field-age and 189 young ultracool dwarfs (spectral types M6-T9, including 40 new discoveries presented here) by directly integrating flux-calibrated optical to mid-IR spectral energy distributions (SEDs). The SEDs consist of low-resolution (RR\sim 150) near-IR (0.8-2.5 μ\mum) spectra (including new spectra for 97 objects), optical photometry from the Pan-STARRS1 survey, and mid-IR photometry from the CatWISE2020 survey and Spitzer/IRAC. Our LbolL_{\mathrm{bol}} calculations benefit from recent advances in parallaxes from Gaia, Spitzer, and UKIRT, as well as new parallaxes for 19 objects from CFHT and Pan-STARRS1 presented here. Coupling our LbolL_{\mathrm{bol}} measurements with a new uniform age analysis for all objects, we estimate substellar masses, radii, surface gravities, and effective temperatures (TeffT_{\mathrm{eff}}) using evolutionary models. We construct empirical relationships for LbolL_{\mathrm{bol}} and TeffT_{\mathrm{eff}} as functions of spectral type and absolute magnitude, determine bolometric corrections in optical and infrared bandpasses, and study the correlation between evolutionary model-derived surface gravities and near-IR gravity classes. Our sample enables a detailed characterization of BT-Settl and ATMO 2020 atmospheric model systematics as a function of spectral type and position in the near-IR color-magnitude diagram. We find the greatest discrepancies between atmospheric and evolutionary model-derived TeffT_{\mathrm{eff}} (up to 800 K) and radii (up to 2.0 RJupR_{\mathrm{Jup}}) at the M/L transition boundary. With 1054 objects, this work constitutes the largest sample to date of ultracool dwarfs with determinations of their fundamental parameters.Comment: Resubmitted to The Astrophysical Journal (ApJ) after a positive referee report. 51 pages, 29 figures, 7 tables. Data presented in this work: https://doi.org/10.5281/zenodo.8315643. Scripts associated with methods: https://github.com/cosmicoder/HIPPVI-Cod

    A technical evaluation of improved animal drawn implements under on-farm conditions

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    Animals are a major source of agriculture power in India and animal drawn implements have evolved to a high degree of simplicity and perfection over a long period of time..

    A Preliminary Observational Search for Circumbinary Disks Around Cataclysmic Variables

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    Circumbinary (CB) disks have been proposed as a mechanism to extract orbital angular momentum from cataclysmic variables (CVs) during their evolution. As proposed by Taam & Spruit, these disks extend outwards to several a.u. and should be detected observationally via their infrared flux or by absorption lines in the ultraviolet spectra of the CV. We have made use of archival HST/STIS spectra as well as our own near-IR imaging to search for observational evidence of such CB disks in seven CVs. Based on the null result, we place an upper limit on the column density of the disk of N_H~10^17 cm^-2.Comment: accepted for publication in the Astronomical Journal (July 2004

    Suppressed Decays of D_s^+ Mesons to Two Pseudoscalar Mesons

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    Using data collected near the Ds*+ Ds- peak production energy Ecm = 4170 MeV by the CLEO-c detector, we study the decays of Ds+ mesons to two pseudoscalar mesons. We report on searches for the singly-Cabibbo-suppressed Ds+ decay modes K+ eta, K+ eta', pi+ K0S, K+ pi0, and the isospin-forbidden decay mode Ds+ to pi+ pi0. We normalize with respect to the Cabibbo-favored Ds+ modes pi+ eta, pi+ eta', and K+ K0S, and obtain ratios of branching fractions: Ds+ to K+ eta / Ds+ to pi+ eta = (8.9 +- 1.5 +- 0.4)%, Ds+ to K+ eta' / Ds+ to pi+ eta' = (4.2 +- 1.3 +- 0.3)%, Ds+ to pi+ K0S / Ds+ to K+ K0S = (8.2 +- 0.9 +- 0.2)%, Ds+ to K+ pi0 / Ds+ to K+ K0S = (5.0 +- 1.2 +- 0.6)%, and Ds+ to pi+ pi0 / Ds+ to K+ K0S < 4.1% at 90% CL, where the uncertainties are statistical and systematic, respectively.Comment: 9 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR

    Measurement of the eta-Meson Mass using psi(2S) --> eta J/psi

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    We measure the mass of the eta meson using psi(2S) --> eta J/psi events acquired with the CLEO-c detector operating at the CESR e+e- collider. Using the four decay modes eta --> gamma gamma, 3pi0, pi+pi-pi0, and pi+pi-gamma, we find M(eta)=547.785 +- 0.017 +- 0.057 MeV, in which the first uncertainty is statistical and the second systematic. This result has an uncertainty comparable to the two most precise previous measurements and is consistent with that of NA48, but is inconsistent at the level of 6.5sigma with the much smaller mass obtained by GEM.Comment: 10 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR
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