UV/IR Mixing for Noncommutative Complex Scalar Field Theory, II (Interaction with Gauge Fields)

We consider noncommutative analogs of scalar electrodynamics and N=2 D=4 SUSY Yang-Mills theory. We show that one-loop renormalizability of noncommutative scalar electrodynamics requires the scalar potential to be an anticommutator squared. This form of the scalar potential differs from the one expected from the point of view of noncommutative gauge theories with extended SUSY containing a square of commutator. We show that fermion contributions restore the commutator in the scalar potential. This provides one-loop renormalizability of noncommutative N=2 SUSY gauge theory. We demonstrate a presence of non-integrable IR singularities in noncommutative scalar electrodynamics for general coupling constants. We find that for a special ratio of coupling constants these IR singularities vanish. Also we show that IR poles are absent in noncommutative N=2 SUSY gauge theory.Comment: 9 pages, 16 EPS figure

Exploring nitrogen limitation for historical and modern soybean genotypes

The United States (USA) and Argentina (ARG) account for over 50% of the global soybean [Glycine max (L.) Merr.] production. Soybean N demand is partially met (50–60%) by the biological nitrogen fixation (BNF) process; however, an unanswered scientific knowledge gap exists on the ability of the BNF process to fulfill soybean N demand at varying yield levels. The overall objective of this study is to explore the potential N limitation using different N strategies for historical and modern soybean genotypes. Four field experiments were conducted during 2016 and 2017 growing seasons in Kansas (USA) and Santa Fe (ARG). Twenty-one historical and modern soybean genotypes released from the 1980s to 2010s were tested under three N treatments: (i) control, without N application (Zero-N); (ii) 56 kg N ha–1 applied at R3-R4 growth stages (Late-N); and (iii) 670 kg ha–1 equally split at planting, R1, and R3–R4 growth stages (Full-N). Historical soybean yield gains, from the 1980s to 2010s, were 29% in the USA and 21% in ARG. Following the yield trend, seed N content increased for modern genotypes in parallel to the reduction on seed protein concentration. Regarding N treatments, Full-N produced 12% yield increase in the USA and 4% in ARG. Yield improvement was mainly related to increases in aboveground biomass, seed number (genotype effect), and to a lesser extent, to seed weight (N effect). This study suggests a potential N limitation for soybean, although there are still questions about the way in which N must be provided to the plant.EEA OliverosFil: Ortez, O.A. Kansas State University. Department of Agronomy; Estados UnidosFil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros. Departamento de Agronomía; ArgentinaFil: Enrico, Juan Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros. Departamento de Agronomía; ArgentinaFil: Prasad, P.V.V. Kansas State University. Department of Agronomy; Estados Unidos. USDA-ARS. Center for Grain and Animal Health Research; Estados UnidosFil: Armstrong, P. USDA-ARS. Center for Grain and Animal Health Research; Estados UnidosFil: Ciampitti, Ignacio A. Kansas State University. Department of Agronomy; Estados Unido

Soja de alto rendimiento: ganancia genética y limitación por nitrógeno

La mejora genética del rendimiento de soja desde la década de 1980 hasta la del 2010 representó 30% promediando en sitios ubicados en los Estados Unidos y Argentina. Para todas las pocas de liberación, la fertilización ad-libitum con N generó hasta un 20% de aumento en rendimientos en EE.UU., y un 5% en Argentina. Los resultados sugieren que soja de alta producción estaría limitada por N para expresar altos rendimientos y contenidos de proteínas, aunque quedan incógnitas acerca de la forma en que este N deba ser provisto. Cabe aclarar que el objetivo del ensayo no es recomendar aplicaciones de fertilizante nitrogenado en soja, pero entender mejor si el N es un factor limitante en el cultivo.EEA OliverosFil: Ortez, O.A. Kansas State University. Department of Agronomy; Estados UnidosFil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros; ArgentinaFil: Enrico, Juan Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros; ArgentinaFil: Ciampitti, Ignacio A. Kansas State University. Department of Agronomy; Estados Unido

B-Pol: Detecting Primordial Gravitational Waves Generated During Inflation

B-Pol is a medium-class space mission aimed at detecting the primordial gravitational waves generated during inflation through high accuracy measurements of the Cosmic Microwave Background (CMB) polarization. We discuss the scientific background, feasibility of the experiment, and implementation developed in response to the ESA Cosmic Vision 2015-2025 Call for Proposals.Comment: Experimental Astronomy - The original publication is available at http://www.springerlink.co

Livestock keepers’ attitudes: Keystone of effective community-based breeding programs

Livestock keepers in southwestern Burkina Faso hold the local Lobi taurine breed, local Zebu cattle, and their crosses. Some communities in the region have begun to implement community-based cattle breeding programs (CBBPs), which involve animal tagging and recording and, potentially, also bull sharing. Based on the hypothesis that the participation of livestock keepers in CBBPs depends on their attitudes towards these programs, we used questionnaires to survey the attitudes of 125 farmers towards cattle breeding strategies and tools. Results were analyzed using principal component analysis. Farmers showed a highly positive attitude towards maintaining the features of their preferred cattle breed, but their attitudes varied substantially towards crossbreeding for breed improvement. Farmers generally agreed that performance was more important than animal appearance, and most of them were willing to cooperate with breeders’ associations but were skeptical about sharing their bulls with other farmers. The majority was reluctant to record performance data, which may be due to a capacity deficit and their confidence in being able to select the best animals based purely on phenotype. Our analysis suggests that breeders’ associations, as a key component of CBBPs, should lay down clear rules and obligations for their members from the outset. Timely consideration of farmers’ attitudes towards different breeding tools may improve their uptake and guarantee the sustainability of CBBPs

Temperature dependence of the breakdown of the quantum Hall effect studied by induced currents

Copyright © 2004 The American Physical SocietyWe have developed a model of the high-current breakdown of the integer quantum Hall effect, as measured in contactless experiments using a highly-sensitive torsion balance magnetometer. The model predicts that, for empirically “low-mobility” samples (μ<75 m2 V−1 s−1), the critical current for breakdown should decrease with, and have a linear dependence on, temperature. This prediction is verified experimentally with the addition of a low-temperature saturation of the critical current at a temperature that depends on both sample number density and filling factor. It is shown that this saturation is consistent with quasielastic inter-Landau-level scattering when the maximum electric field in the sample reaches a large enough value. In addition we show how this model can be extended to give qualitative agreement with experiments on high-mobility samples

Optical Properties and Structure of Most Stable Subnanometer (ZnAs2)n Clusters

ZnAs2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence spectra of ZnAs2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands which demonstrate the blue shift from the line of free exciton in bulk crystal. We performed the calculations aimed to find the most stable clusters in the size region up to size of the zeolite Na-X supercage. The most stable clusters are (ZnAs2)6 and (ZnAs2)8 with binding energies of 7.181 eV and 8.012 eV per (ZnAs2)1 formula unit respectively. Therefore, we attributed two bands observed in absorption and PL spectra to these stable clusters. The measured Raman spectrum of ZnAs2 clusters in zeolite was explained to be originated from (ZnAs2)6 and (ZnAs2)8 clusters as well. The PL spectrum of ZnAs2 clusters produced by laser ablation consists of a single band which has been attributed to emission of (ZnAs2)8 cluster.Comment: Article accepted for publication in Physica B: Physics of Condensed Matte