322 research outputs found

    Influence of different transplanting date and weed management practices on yield and quality of basmati rice (Pusa Basmati-1509)

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    A field experiment was conducted during kharif 2014 at students’ farm of Chaudhary Charan Singh Haryana Agricultural University, college of agriculture, Kaul (Kaithal). The experiment consisted of four transplanting dates (June 15, July 5, July 25 and August 15) in main plots and six weed control treatments in sub plots treatments consisted of pre-emergence application of pretilachlor, oxadiargyl alone and sequential application of pre and post emergence herbicides viz., pretilachlor fb bispyribac, oxadiargyl fb bispyribac, weed free check and unweeded check. Based on research investigation it was observed that early transplanting dates (June 15 and July 5) produced taller plant, higher tillers/m2 and crop dry matter accumulation at all growth stages. Early transplanting produced significantly higher number of effective tillers/m2 (263) along with higher number of filled grain/ panicle (85) than delayed planting (July 25 and August 15). The 1000-grain weight was not affected by time of transplanting. The highest grain yield (4363 kg/ha) was recorded under June 15 transplanting which was statistically at par to the grain yield (4058 kg/ha) obtained under July 5 transplanting. Among the weed management practices tried, weed free check resulted in the highest values of plant height (104.2 cm), tillers/m2 (305), crop dry matter accumulation (964 g/ m2), effective tillers/m2 (271), grains length (8.5 cm), filled grains/panicle (86.3) as well as grain (4516 kg/ha) and straw yield (5506 kg/ha) which were however, comparable to pre-emergence application of oxadiargyl followed by bispyribac-sodium applied at 25 DAT and pretilachlor followed by bispribac-sodium at 25DAT

    Jet propagation and the asymmetries of CSS radio sources

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    As Compact Steep Spectrum radio sources have been shown to be more asymmetrical than larger sources of similar powers, there is a high probability that they interact with an asymmetric medium in the central regions of the host elliptical galaxy. We consider a simple analytical model of the propagation of radio jets through a reasonable asymmetric environment and show that they can yield the range of arm-length and luminosity asymmetries that have been observed. We then generalize this to allow for the effects of orientation, and quantify the substantial enhancements of the asymmetries that can be produced in this fashion. We present two-dimensional and three-dimensional simulations of jets propagating through multi-phase media and note that the results from the simulations are also broadly consistent with the observations.Comment: 11 pages, 6 figures, 1 table, accepted for publication in A&

    Electronic Transport and Fermi Surface Topology of Zintl phase Dirac Semimetal SrZn2Ge2

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    We report a comprehensive study on the electronic transport properties of SrZn2_2Ge2_2 single crystals. The in-plane electrical resistivity of the compound exhibits linear temperature dependence for 80 K < T < 300 K, and T^2 dependence below 40 K, consistent with the Fermi liquid behavior. Both the transverse and longitudinal magnetoresistance exhibit a crossover at critical field B* from weak-field quadratic-like to high-field unsaturated linear field dependence at low temperatures (T \leq 50 K). Possible sources of linear magnetoresistance are discussed based on the Fermi surface topology, classical and quantum transport models. The Hall resistivity data establish SrZn2_2Ge2_2 as a multiband system with contributions from both the electrons and holes. The Hall coefficient is observed to decrease with increasing temperature and magnetic field, changing its sign from positive to negative. The negative Hall coefficient observed at low temperatures in high fields and at high temperatures over the entire field range suggests that the highly mobile electron charge carriers dominate the electronic transport. Our first-principles calculations show that nontrivial topological surface states exist in SrZn2_2Ge2_2 within the bulk gap along the {\Gamma}-M path. Notably, these surface states extend from the valence to conduction band with their number varying based on the Sr and Ge termination plane. The Fermi surface of the compound exhibits a distinct tetragonal petal-like structure, with one open and several closed surfaces. Overall, these findings offer crucial insights into the mechanisms underlying the electronic transport of the compound.Comment: 12 pages, 9 figure

    Multivariate analysis of pearl millet data to delineate genetic variation

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    Loss of biodiversity not only disturbs the process of plant development aimed at genetic amelioration but also disrupts the fundamental services that ecosystems provided to humanity. Assessment of variability is a multidimensional problem. The multivariate statistics can help in a comparative assessment of genetic variability. A set of 66 lines of pearl millet was analyzed for cluster and principal component analysis (PCA). PCA identified six principal components which explained 77.7 per cent of total variability among the 66 genotypes. The PC1 characters –main ear weight, dry fodder weight, total ear weight, grain yield, growth rate and plant height, the major characters of plant biomass and the basis for grain yield contributed maximum 35.94 per cent variability among the lines. The remaining PCs accounted for progressively lesser and lesser amount of variability. The lowest contribution 5.27 per cent was recorded by PC 6, the characters grain starch, starch recovery and ear girth. Only grain starch contributed positively to all the six components. The genotypes 50 (77/371), 3 (IPC-115), 41 (204/2 MP), 12 (IPC-1462), 37 (TCH-37-1), 22 (TCH-10-1), 61 (1307), 14 (862-P2), 20 (TCH-3-2), 40 (204-2-3) were found to be better performers and diverse on the basis of principal factor scores with regard to grain yield and yield contributing characters. Hierarchical cluster analysis grouped 66 genotypes into six clusters, cluster 1 included maximum number of 21 genotypes and clusters 3 and 6 had the lowest number of 6 genotypes. The results on hierarchical cluster analysis almost mimicked the PCA. The grouping pattern of genotypes obtained by cluster analysis and PCA plots was almost similar. A wide range of diversity for most of the traits observed would enable to pick lines with suitable traits to be used in a breeding programme. Genetic diversity was not essentially associated with geographic diversity

    Correction for a measurement artifact of the Multi-Angle Absorption Photometer (MAAP) at high black carbon mass concentration levels

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    The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon (BC) measurements. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments characterized by high black carbon concentrations. The artifact occurs after a filter spot change – as BC mass is accumulated on a fresh filter spot, the attenuation of the light (raw signal) is weaker than anticipated. This causes a sudden decrease, followed by a gradual increase in measured BC concentration. The artifact is present in the data when the BC concentration exceeds ~3 μg m&lt;sup&gt;−3&lt;/sup&gt; at the typical MAAP flow rate of 16.7 L min&lt;sup&gt;−1&lt;/sup&gt; or 1 m&lt;sup&gt;3&lt;/sup&gt; h&lt;sup&gt;−1&lt;/sup&gt;. The artifact is caused by erroneous dark counts in the photodetector measuring the transmitted light, in combination with an instrument internal averaging procedure of the photodetector raw signals. It was found that, in addition to the erroneous temporal response of the data, concentrations higher than 9 μg m&lt;sup&gt;−3&lt;/sup&gt; (at the flow rate of 16.7 L min&lt;sup&gt;−1&lt;/sup&gt;) are underestimated by the MAAP. The underestimation increases with increasing BC accumulation rate. At a flow rate of 16.7 L min&lt;sup&gt;−1&lt;/sup&gt; and concentration of about 24 μg m&lt;sup&gt;−3&lt;/sup&gt; (BC accumulation rate ~0.4 μg min&lt;sup&gt;−1&lt;/sup&gt;), the underestimation is about 30%. There are two ways of overcoming the MAAP artifact. One method is by logging the raw signal of the 165° photomultiplier measuring the reflected light from the filter spot. As this signal is not affected by the artifact, it can be converted to approximately correct absorption and BC values. However, as the typical print formats of the MAAP do not give the reflected signal as an output, a semi-empirical correction method was developed based on laboratory experiments to correct for the results in the post-processing phase. The correction function was applied to three MAAP datasets from Gual Pahari (India), Beijing (China), and Welgegund (South Africa). In Beijing, the results could also be compared against a photoacoustic spectrometer (PAS). The correction improved the quality of all three MAAP datasets substantially, even though the individual instruments operated at different flow rates and in different environments

    Trends in the recovery of phosphorus in bioavailable forms from wastewater

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    Addressing food security issues arising from phosphorus (P) scarcity is described as one of the greatest global challenges of the 21st Century. Dependence on inorganic phosphate fertilisers derived from limited geological sources of P creates an urgent need to recover P from wastes and treated waters, in safe forms that are also effective agriculturally – the established process of P removal by chemical precipitation using Fe or Al salts, is effective for P removal but leads to residues with limited bioavailability and contamination concerns. One of the greatest opportunities for P recovery is at wastewater treatment plants (WWTPs) where the crystallisation of struvite and Ca-P from enhanced biological P removal (EBPR) sludge is well developed and already shown to be economically and operationally feasible in some WWTPs. However, recovery through this approach can be limited to &lt;25% efficiency unless chemical extraction is applied. Thermochemical treatment of sludge ash produces detoxified residues that are currently utilised by the fertiliser industry; wet chemical extraction can be economically feasible in recovering P and other by-products. The bioavailability of recovered P depends on soil pH as well as the P-rich material in question. Struvite is a superior recovered P product in terms of plant availability, while use of Ca-P and thermochemically treated sewage sludge ash is limited to acidic soils. These technologies, in addition to others less developed, will be commercially pushed forward by revised fertiliser legislation and foreseeable legislative limits for WWTPs to achieve discharges of &lt;1 mg P/L

    FOREST CANOPY DENSITY ASSESSMENT USING HIGH RESOLUTION LISS-4 DATA IN YAMUNANAGAR DISTRICT, HARYANA

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    Forest plays an important role not only in providing ecological services but also economic goods to human beings. However, with increase in population there is a wide gap between demand and supply of these goods and services. This has lead to reduction in forest cover which needs to be taken care on regular time interval. To manage the existing forest area and also to increase the forest cover Forest Canopy Density (FCD) methodology is the main factor which was given by International Tropical timber Organization (ITTO). High resolution remote sensing LISS-4 data gives us chance to assess the quality of forest in terms of FCD as Rikimaru et al (1999) stated that FCD is one important parameter to assess forest cover quality. High resolution LISS-4 data analysis for FCD was never attempted before. Authors here attempted to assess the FCD utilizing methodology adopted by Rikimaru (1999), Huang (2001), Azizia (2008). The adopted methodology is one of the most efficient and cost effective way to derive the FCD. For this study Resourcesat-2 LISS-4 post monsoon data of year 2017 for Yamunanagar district was used to assess FCD within notified forest boundary. Notified forest boundaries at cadastral level prepared previously by Haryana Space Applications Centre (HARSAC) was used. The degree of forest canopy density is expressed in percentages: i.e. &lt;&thinsp;10% FCD (scrub land), 10–20% (Open Forest-I), 20–40% (Open Forest-II), 40–60% (Moderate Dense), 60–80% (Medium Dense) and &gt;&thinsp;80% (Highly Dense). Forest Canopy Density was based on three indices i.e. Advanced Vegetation Index (AVI), Bare Soil Index (BSI) and Canopy Shadow Index (CSI). Accuracy assessment was done based on ground data and comparison with Coterminous Google Earth imagery and it was found that the devised methodology has achieved overall accuracy of 93% with kappa coefficient of 0.9153. The result shows that maximum forest area in Yamunanagar district is in medium dense FCD category which is approximately 23948.08 acres. This study tells us that 24.2% of the total forest area is under scrub land and open forest which should be focussed for activities in working plan to increase the forest cover. This paper highlights the utility of high resolution satellite data for monitoring and management of forest and improvement in its quality. This attempt provided large scale (1&thinsp;:&thinsp;10,000) maps to the forest managers to better equip them in planning for afforestation, reforestation and rehabilitation of water logged areas, environment management and their future aspect
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