1,967 research outputs found

    Effects of the second crop on maize yield and yield components in organic agriculture

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    The second crop use in organic agriculture is a known method of maintaining the soil tilth, soil protection against environmental deterioration, soil nutrients conservation and even the weed control. The nitrogen conservation from previous leguminose crop is even more important, especially in the organic agriculture where use of N-fertilizers is the strictly forbiden, and second crops can be used as a catch crops for nutrients in rotation prior to the crops with the high N requirement. The choice of the proper second crop has, however, been insufficiently investigated, especially for agri-environmental conditions of the Panonian agricultural area in Croatia. The second crop experiment was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The aim of the experiment was to investigate the effects of different second crops and their combinations on maize (Zea mais L.) yield and yield components in organic agriculture after soybean (Glycine max L.) in crop rotation. The experimental design was set up as a CRBD in four repetitions, with soybean as a previous crop in crop rotation. The six second crop treatments were: O – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of the WW and FP; and RP – mixture of RY and FP. The WW treatment had the highest second crop dry mass, whereas FP had the lowest dry mass. The highest plant density was recorded for FP, and it was higher than the RP plant density, which also had the lowest plant height. The achieved maize yields were the highest for RY, but they were not significanlty different from the O, RP, and WW treatments. However, the yield achieved by RY treatment was significantly higher than the yields recorded for WP and FP treatments. The absolute mass and hectolitre mass did not show any statistical differences among treatments

    Control of multiatom entanglement in a cavity

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    We propose a general formalism for analytical description of multiatomic ensembles interacting with a single mode quantized cavity field under the assumption that most atoms remain un-excited on average. By combining the obtained formalism with the nilpotent technique for the description of multipartite entanglement we are able to overview in a unified fashion different probabilistic control scenarios of entanglement among atoms or examine atomic ensembles. We then apply the proposed control schemes to the creation of multiatom states useful for quantum information.Comment: 11 pages, 1 figure. Finalized versio

    The economic sustainability of second crops implementation in organic maize production

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    Although organic crop production has numerous advantages, concerns about economic sustainability, both environmental and financial, make farmers reluctant to convert their conventional production into the organic production. Certain agricultural methods, such as second crop use, can alleviate some problems regarding soil tilth, erosion prevention, nutrients availability and weed control, thus contributing toward more sustainable crop production. Also, the added value crop growth, such as maize (Zea mais L.) hybrid's parental line production, with lower yields but higher prices, can contribute to sustainability of organic production. In order to test the hypothesis that the use of second crops can contribute toward the sustainability of organically grown maize after soybean (Glycine max L.) as a previous crop in the crop rotation, the experimental site was established in Valpovo, Croatia, in the eutric brown soil type, during the years 2005 and 2006. The experimental design was set up as a CRBD in four repetitions, with six second crop treatments: CT – Control, without second crop; WW – winter wheat (Triticum aestivum L.) second crop; RY – rye (Secale cereale L.) second crop; FP – fodder pea (Pisum arvense L.) second crop; WP – mixture of WW and FP; and RP – mixture of RY and FP. In order to assess the soil surface protection and evaluate the weed suppression, the second crop coverage had been recorded. Regarding the economic sustainability, the second crop use depending costs were analysed in relation to the extra produced maize yield. The RY treatment had the highest profitability, followed by WW, RP and O. The WP and FP revealed lower relative profitability than O, thus presenting the evidence of sustainability risk of these treatments

    Determination of mechanical properties of historical paper based on NIR spectroscopy and chemometrics - a new instrument

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    Due to sampling restrictions in the analysis of cultural heritage materials, non-destructive approaches are intensively sought for. While NIR spectrometry has rarely been used for this purpose due to the complexity of the spectra, chemometric methods can be used to extract the necessary information. For the purpose of determination of mechanical properties of historical paper, partial least squares approach was used and it is shown that tensile strength, and tensile strength after folding, can be estimated based on NIR spectra. As the mechanical properties of paper-based objects define their accessibility, a new dispersive portable instrument was built, which will enable us to rapidly survey the condition of library and archival collections

    A Middle Jurassic Radiolarite-Clastic Succession from the Medvednica Mt. (NW Croatia

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    On the NW part of Medvednica Mt. radiolarites with carbonate olistoliths, shales and siltites, matrix-supported conglomerates and basic volcanic rocks were investigated. This facies association is informally named the Poljanica unit. Major element geochemical data indicate deposition of radiolarites in the vicinity of the middle oceanic ridge, while sedimentological data indicate deposition in an area closer to the continent. Shales and siltites, as well as matrix-supported conglomerates, were deposited in short periods characterised by increased input of terrigenous material. Matrix-supported polymict conglomerates are composed of silicified shales, lithic graywackes, cherts and metabasalts, and were deposited by debris flow mechanisms as a consequence of synsedimentary tectonic activity. Carbonate olistoliths are composed of biomicrosparite, and jointly with deformed radiolarian cherts compose an olistostrome. Basic volcanic rocks represent high-Ti tholeiitic basalts formed in the MORB realm. Micropalaeontological investigation of radiolarite samples proved the Middle Jurassic (latest Bajocian - early Bathonian to late Bathonian - early Callovian) age of the Poljanica unit. Additionally, a new radiolarian species Theocapsomma medvednicensis n.sp. has been described. Conodont analyses from carbonate olistoliths in radiolarites proved their Triassic age. The investigated radiolarite-clastic succession is the result of subduction processes. Further continuation of this process caused incorporation of these deposits into the accretionary prism, where they were brought in direct contact with Triassic volcanic rocks and radiolarites (in the form of a tectonic mélange). Based on the lithological similarities with the Middle Jurassic turbidite-olistostrome successions in the Western Carpathians and Northern Calcareous Alps, the study area is considered to be part of the Meliata-Hallstatt Ocean

    Amperometric separation-free immunosensor for real-time environmental monitoring

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    Immunoanalytical techniques have found widespread use due to the characteristics of specificity and wide applicability for many analytes, from large polymer antigens, to simple haptens, and even single atoms. Electrochemical sensors offer benefits of technical simplicity, speed and convenience via direct transduction to electronic equipment. Together, these two systems offer the possibility of a convenient, ubiquitous assay technique with high selectivity. However, they are still not widely used, mainly due to the complexity of the associated immunoassay methodologies. A separation-free immunoanalytical technique is described here, which has allowed for the analysis of atrazine in real time and in both quasi-equilibrium and stirred batch configurations. It illustrated that determinations as low as 0.13 muM (28 ppb) could be made using equilibrium incubation with an analytical range of 0.1-10 muM. Measurements could be made between 1 and 10 mM within several minutes using a real-time, stirred batch method. This system offers the potential for fast, simple, cost-effective biosensors for the analysis of many substances of environmental, biomedical and pharmaceutical concern. (C) 2001 Elsevier Science B.V. All rights reserved

    All Stable Characteristic Classes of Homological Vector Fields

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    An odd vector field QQ on a supermanifold MM is called homological, if Q2=0Q^2=0. The operator of Lie derivative LQL_Q makes the algebra of smooth tensor fields on MM into a differential tensor algebra. In this paper, we give a complete classification of certain invariants of homological vector fields called characteristic classes. These take values in the cohomology of the operator LQL_Q and are represented by QQ-invariant tensors made up of the homological vector field and a symmetric connection on MM by means of tensor operations.Comment: 17 pages, references and comments adde

    Blocking Zika virus vertical transmission.

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    The outbreak of the Zika virus (ZIKV) has been associated with increased incidence of congenital malformations. Although recent efforts have focused on vaccine development, treatments for infected individuals are needed urgently. Sofosbuvir (SOF), an FDA-approved nucleotide analog inhibitor of the Hepatitis C (HCV) RNA-dependent RNA polymerase (RdRp) was recently shown to be protective against ZIKV both in vitro and in vivo. Here, we show that SOF protected human neural progenitor cells (NPC) and 3D neurospheres from ZIKV infection-mediated cell death and importantly restored the antiviral immune response in NPCs. In vivo, SOF treatment post-infection (p.i.) decreased viral burden in an immunodeficient mouse model. Finally, we show for the first time that acute SOF treatment of pregnant dams p.i. was well-tolerated and prevented vertical transmission of the virus to the fetus. Taken together, our data confirmed SOF-mediated sparing of human neural cell types from ZIKV-mediated cell death in vitro and reduced viral burden in vivo in animal models of chronic infection and vertical transmission, strengthening the growing body of evidence for SOF anti-ZIKV activity

    Heats of Immersion of Uranium Oxides in Water. II. Annealing Experiments

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    Heats of immersibn of original and annealed uranium oxide samples in water were measured. Whereas the unannealed samples gave values in accordance with the already reported results, the values of annealed samples were lower. The structures were determined by the X-ray technique, and the wetting behaviour is cHscusseil on the basis of the present knowledge of uranium oxides

    Heat of Immersion of Uranium Dioxide in Water

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    Heats of immersion of U02 powders in water were d etermined by calorimetric m easurements. The integral heat of immersion at 25°C was found to be 490 erg/ cm2 with a n uncertainty± 70/o for stoichiometric U02. The value is linearly increasing with increasing non-stoichiometry of the powders up to 790 erg/cm!± 7° / o for U30 8• The result is not influenc ed by different p a rticle size distribution, obtained by some different me thods of synthesis of U02 powders
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