7,217 research outputs found

    Lattice quark masses: a non-perturbative measurement

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    We discuss the renormalization of different definitions of quark masses in the Wilson and the tree-level improved SW-Clover fermionic action. For the improved case we give the correct relationship between the quark mass and the hopping parameter. Using perturbative and non-perturbative renormalization constants, we extract quark masses in the \MSbar scheme from Lattice QCD in the quenched approximation at β=6.0\beta=6.0, β=6.2\beta=6.2 and β=6.4\beta=6.4 for both actions. We find: \bar{m}^{\MSbar}(2 GeV)=5.7 \pm 0.1 \pm 0.8 MeV, m_s^{\MSbar}(2GeV)= 130 \pm 2 \pm 18 MeV and m_c^{\MSbar}(2 GeV) = 1662\pm 30\pm 230 MeV.Comment: 21 pages, 4 figures, typos corrected, no result change

    Quark masses and the chiral condensate with a non-perturbative renormalization procedure

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    We determine the quark masses and the chiral condensate in the MSbar scheme at NNLO from Lattice QCD in the quenched approximation at beta=6.0, beta=6.2 and beta=6.4 using both the Wilson and the tree-level improved SW-Clover fermion action. We extract these quantities using the Vector and the Axial Ward Identities and non-perturbative values of the renormalization constants. We compare the results obtained with the two methods and we study the O(a) dependence of the quark masses for both actions.Comment: LATTICE98(spectrum), 3 pages, 1 figure, Edinburgh 98/1

    Non-perturbative Renormalization of the Complete Basis of Four-fermion Operators and B-parameters

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    We present results on the B-parameters BKB_K, B73/2B^{3/2}_7 and B83/2B^{3/2}_8, at β=6.0\beta=6.0, with the tree-level Clover action. The renormalization of the complete basis of dimension-six four-fermion operators has been performed non-perturbatively. Our results for BKB_K and B73/2B^{3/2}_7 are in reasonable agreement with those obtained with the (unimproved) Wilson action. This is not the case for B83/2B^{3/2}_8. We also discuss some subtleties arising from a recently proposed modified definition of the B-parameters.Comment: Talk presented at Lattice '97, Edinburgh (UK), July 1997. LaTeX 3 pages, uses espcrc

    Delta M_K and epsilon_K in SUSY at the Next-to-Leading order

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    We perform a Next-to-Leading order analysis of Delta S=2 processes beyond the Standard Model. Combining the recently computed NLO anomalous dimensions and the B parameters of the most general Delta S=2 effective Hamiltonian, we give an analytic formula for Delta M_K and epsilon_K in terms of the Wilson coefficients at the high energy scale. This expression can be used for any extension of the Standard Model with new heavy particles. Using this result, we consider gluino-mediated contributions to Delta S=2 transitions in general SUSY models and provide an improved analysis of the constraints on off-diagonal mass terms between the first two generations of down-type squarks. Finally, we improve the constraints on R-violating couplings from Delta M_K and epsilon_K.Comment: 20 pages, 1 figure, uses JHEP.cls; the magic numbers in eq. (2.7), previously given in the basis (13) of hep-ph/9711402, are now given in the basis (2.3) of this work. All numerical results are unchange

    Energy Demand in Sugarcane Residue Collection and Transportation

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    Sugarcane production system is in transition, mainly due to its harvesting process. Harvest through burning has been gradually replaced by mechanized processes, providing another by-product to be explored: sugarcane trash. In Brazil, through of the sugarcane trash, São Paulo state itself produces around 210.4 million BOE – barrel of oil equivalent (1,251,952 TJ ), which could supply consumers through cogeneration or for further second generation ethanol. For the sugarcane trash to be collected, mechanized processes are required, such as windrowing, gathering, and transporting. In agricultural production systems, embodied energy is affected by the mechanization level. In order to assess environmental performance by the energy point-of-view, analysis of energy flows provides subsidies for the decision makers. Thus, this study aimed to determine the material and energy flows for sugarcane trash collection and to identify its critical steps. The sugarcane variety grown was RB855113, spaced between rows 1.4 m, in the second cut, and yield of 108 Mg ha-1. The following mechanized operations were evaluated: windrowing, gathering, and transport, using material and energy flow as supporting tools. Regarding the energy balance, sugarcane trash collection system is feasible. Among evaluated operations, gathering is the one that presented higher energy demand. Fuel in harvesting is the main factor that affects energy demand for having sugarcane trash available.   Keywords: material flow, mechanized harvest, bioenergy, biofue

    Spectrophotometric determination of the deltamethrin

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    In the province of Corrientes is found highest production of indoor plants from all Argentina, specially in the northeast of this province. This is because the low frequency orthelack of frosts, allowing a lower cost in the production, since heating is not needed. In this type of cultive is commonly used thedeltamethrin, as the result of this, the validation of a simple method comparable with the gas chromatography for the determination of this Pesticide on both, irrigation and consumption water, was studied. In this work, a spectrophotometric method is proposed for the determination of deltamethrin inirrigation water from the area of flower crops located in the Department of Concepción in the province of Corrientes. Deltamethrin solutions in a range from 0,025 to 1 mg/L on irrigation water were prepared. The absorbance spectrum was scanned between 200 and 400 nm. The maximum absorbance was found at 220 nm. A calibration curve in the range from 0.025 to 1 mg/L, responded to A = (0.3246± 0.0224) C + (0.0096 ± 0.0068) with R2 = 0.998. The % RSD was 0.961 indicating good repeatability for the analytical procedure. The accuracy in the recovery experience was 99.0 - 109.6%. The statistical comparison using the t-test and the F-test indicates that there are no significant differences between GC and spectrophotometric methods, with a confidence level of 95%. The specificity and intermediate accuracy tests were satisfactory.Fil: Gimenez, L. I.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Michellod, A. M. M.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Jorge, M. J.. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Pila, Andrea Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; ArgentinaFil: Bordón, Alexander Germán. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Profeta, Mariela Inés. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Romero, Jorge Marcelo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; ArgentinaFil: Jorge, Nelly Lidia. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Departamento de Química; Argentin

    Energy Embodiment in Brazilian Agriculture: An Overview of 23 Crops

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    The amount of energy required to produce a commodity or to supply a service varies from one production system to another and consequently giving rise to differing levels of environmental efficiency. Moreover, since energy prices have been continuously increasing over time, this energy amount may be a factor that has economic worth. Biomass production has a variety of end-products such as food, energy, and fiber; thus, taking into account the similarity in end-product of different crops (e.g.: sunflower, peanuts, or soybean for oil) it is possible to evaluate which crops require less energy per functional unit, such as starch, oil, and protein. This information can be used in decision-making about policies for food safety or bioenergy. In this study, 23 crops were evaluated allowing for a comparison in terms of energy embodied per functional unit. Crops were grouped as follows: starch, oil, horticultural, perennial and fiber, to provide for a deeper analysis of alternatives for the groups, and subsidize further studies comparing conventional and alternative production systems such as organic or genetically modified organisms, in terms of energy. The best energy balance observed was whole sugarcane (juice, bagasse and straw) with a surplus of 268 GJ ha−1 yr−1; palm shows the highest energy return on investment with a ratio of approximately 30:1. For carbohydrates and protein production, cassava and soybean, respectively, emerged as the crops offering the greatest energy savings in the production of these functional foods

    Intellectual property & technology transfer practices of public Brazilian science and technology institutes: multiple case studies.

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    The "Technological Innovation Act", promulgated in Brazil in 2004, represents the main legal framework implemented to promote technological innovation and to delineate a favorable scenario for scientific development in Brazil. It regulates specially the relationship between Scientific and Technological Institutions (STI) - such as universities and public research institutes - and private companies in Brazil. Among other things, the law determines that each STI should compose a Technological Innovation Center (NIT, as its acronym in Portuguese) to act as an interface of the STI and its markets. These centers are equivalent to what is internationally called Technology Transfer Office and have as main responsibility to transfer the knowledge and inventions generated at Public Research Institutes (PRI) to private sector.This paper describes and provides some reflections upon the experience of three NIT, located in the State of São Paulo (Brazil): Innovation Agency of University of Campinas (Inova/ Unicamp); Innovation Agency of Federal University of São Carlos (UFSCar) and Embrapa Informatics of Agriculture. The analysis was focused on the following issues: history, legal structure and organizational model, mission and activities, relationships and results.RWIO 2014

    Precision scans of the pixel cell response of double sided 3D pixel detectors to pion and x-ray beams

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    hree-dimensional (3D) silicon sensors offer potential advantages over standard planar sensors for radiation hardness in future high energy physics experiments and reduced charge-sharing for X-ray applications, but may introduce inefficiencies due to the columnar electrodes. These inefficiencies are probed by studying variations in response across a unit pixel cell in a 55μm pitch double-sided 3D pixel sensor bump bonded to TimePix and Medipix2 readout ASICs. Two complementary characterisation techniques are discussed: the first uses a custom built telescope and a 120GeV pion beam from the Super Proton Synchrotron (SPS) at CERN; the second employs a novel technique to illuminate the sensor with a micro-focused synchrotron X-ray beam at the Diamond Light Source, UK. For a pion beam incident perpendicular to the sensor plane an overall pixel efficiency of 93.0±0.5% is measured. After a 10o rotation of the device the effect of the columnar region becomes negligible and the overall efficiency rises to 99.8±0.5%. The double-sided 3D sensor shows significantly reduced charge sharing to neighbouring pixels compared to the planar device. The charge sharing results obtained from the X-ray beam study of the 3D sensor are shown to agree with a simple simulation in which charge diffusion is neglected. The devices tested are found to be compatible with having a region in which no charge is collected centred on the electrode columns and of radius 7.6±0.6μm. Charge collection above and below the columnar electrodes in the double-sided 3D sensor is observed

    The Mass of the Convective Zone in FGK Main Sequence Stars and the Effect of Accreted Planetary Material on Apparent Metallicity Determinations

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    The mass of the outer convective zone in FGK main sequence stars decreases dramatically with stellar mass. Therefore, any contamination of a star's atmosphere by accreted planetary material should affect hotter stars much more than cool stars. If recent suggestions that high metal abundances in stars with planets are caused by planetesimal accretion are correct, then metallicity enhancements in earlier-type stars with planets should be very pronounced. No such trend is seen, however.Comment: Submitted ApJ Letters March 26th; accepted April 30th. 12 pages, 2 figure
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