2,517 research outputs found

    Spectral analysis of Markarian 421 and Markarian 501 with HAWC

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    The Hight Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory monitors the gamma-ray sky in the energy range from 100 GeV to 100 TeV and has detected two very high energy (VHE) blazars: Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501) in 1.5 years of observations. In this work, we present the spectral analysis above 1 TeV of both sources using a maximum likelihood method and an artificial neural network as an energy estimator. The main objectives are to constrain the spectral curvature of Mrk 421 and Mrk 501 at \sim5 TeV using the EBL models from Gilmore et al. (2012) and Franceschini et al. (2008).Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

    Predicting global geographical distribution of "Lolium rigidum" under climate change

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    “Lolium rigidum Gaud.” (vallico) es una de las malezas más extendidas y perjudiciales en los cultivos de cereales de invierno. Un modelo bioclimático para esta especie fue desarrollado utilizando CLIMEX. El modelo fue validado con los registros de esta especie en Estados Unidos y Oceanía y utilizado para predecir la distribución potencial global de “L. rigidum” bajo el clima actual y dos escenarios de cambio climático. Las proyección en virtud de las condiciones climáticas actuales indican que “L. rigidum” no ocupa todo el área disponible para su expansión. Considerando los escenarios climáticos futuros, el área potencial de expansión aumentará 3,79% y 5,06% bajo los escenarios moderado y extremo, respectivamente. La proyección del modelo mostró un avance gradual de “L. rigidum” en Norteamérica, Europa, Sudamérica y Asia, mientras que en África y Oceanía se prevé una regresión. Estos resultados proporcionan Los conocimientos necesarios para identificar y poner de relieve las posibles zonas de riesgo de invasión.“Lolium rigidum” Gaud. (rigid ryegrass) is one of the most extended and harmful weeds in winter cereal crops. A bioclimatic model for this species was developed using CLIMEX. The model was validated with records from North America and Oceania and used to assess the global potential distribution of “L. rigidum” under the current climate and under two climate change scenarios. The projection under current climate conditions indicated that “L. rigidum” does not occupy the full extent of the climatically suitable area available to it. Under future climate scenarios, the infested potential area will increase 3.79% in the low-emission CO2 scenario and 5.06% under the most extreme scenario. The model projection showed a gradual advance of rigid ryegrass in North America, Europe, South America and Asia, whilst in Africa and Oceania it indicated regression. These results provide the necessary knowledge for identifying and highlighting the potential invasion risk areas

    QTL Mapping in Tropical Maize: III. Genomic Regions for Resistance to Diatraea spp. and Associated Traits in Two RIL Populations

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    The southwestern corn borer (SWCB, Diatraea grandiosella Dyar) and sugarcane borer (SCB, Diatraea saccharalis Fabricius) are two related insect species that cause serious damage in maize production in subtropical and tropical regions of Central and Latin America. We analyzed quantitative trait loci (QTL) involved in resistance to the first generation of both borer species in two recombinant inbred line (RIL) populations from crosses CML131 (susceptible) × CML67 (resistant) and Ki3 (susceptible) × CML139 (resistant). Resistance was evaluated as leaf feeding damage (LFD) in replicated field trials across several environments under artificial infestation. Leaf protein concentration and leaf toughness were evaluated in one environment as putative components of resistance. The method of composite interval mapping was employed for QTL detection with RFLP linkage maps derived for each population of RIL. Estimates of the genotypic and genotype × environment interaction variances for SWCB LFD and SCB LFD were highly significant in both populations. Heritabilities ranged from 0.50 to 0.75. In Population CML131 × CML67, nine and eight mostly identical QTL were found for SWCB LFD and SCB LFD, respectively, explaining about 52% of the phenotypic variance () for each trait. In Population Ki3 × CML139, five QTL for SWCB LFD were detected, explaining 35.5% of . Several of these QTL were found in regions containing QTL for leaf protein concentration or leaf toughness. A low number of QTL in common between the two RIL populations and between RIL and corresponding populations of F2:3 indicated that the detection of QTL depended highly on the germplasm and population type. Consequently, chances of successful application of marker-based selection (MBS) for corn borer resistance are reduced when QTL are not identified in the germplasm in which the final selection will be carried out

    QTL Mapping in Tropical Maize: I. Genomic Regions Affecting Leaf Feeding Resistance to Sugarcane Borer and Other Traits

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    Sugarcane borer (SCB), Diatraea saccharalis Fabricius, is a serious pest in tropical maize production areas in the Americas. Little is known about the genetic resistance of maize genotypes to this pest. In this study, we mapped and characterized quantitative trait loci (QTL) affecting resistance to the leaf feeding generation of SCB (1SCB), grain yield under both protection (GYP) and infestation (GYI) with SCB larvae, and plant height (PITT). A total of 171 F2 genotypes derived from cross CML131 (susceptible) × CML67 (resistant) 93 RFLP marker loci were used in QTL analyses. F3 lines were evaluated for the above traits and grain yield reduction (GYR) in field experiments with two replications at two or three tropical environments. Resistance was assessed by rating leaf feeding damage after artificial infestation with SCB larvae. The method of composite interval mapping with selected markers as cofactors was used for detection and characterization of QTL. Resistance to 1SCB was significantly affected by 10 putative QTL on Chromosomes 1, 2, 5, 7, 8, 9, and 10. These showed predominantly additive gene action and explained 65.0% of the phenotypic variance and 93.5% of the genetic variance in a simultaneous fit. Six QTL for GYP, five QTL for GYI with primarily dominant genetic effects, and four QTL for PHT with primarily additive genetic effects were identified, explaining in total about one third of the phenotypic variance for the respective trait. No more than one putative QTL was found to be common between different characters. QTL × environment interaction was found to be significant for 1SCB ratings only. Based on these data, prospects for improving 1SCB resistance by marker-assisted breeding are promising

    QTL Mapping in Tropical Maize: II. Comparison of Genomic Regions for Resistance to Diatraea spp.

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    Southwestern corn borer (SWCB), Diatraea grandiosella (Dyar), and the sugar cane borer (SCB), Diatraea saccharalis (Fabricius), are serious insect pests in maize (Zea mays L.) production areas of Central America and the southern USA. We mapped and characterized quantitative trait loci (QTL) affecting resistance to the leaf feeding generation of SWCB(1 SWCB), compared these QTL with those for resistance to the leaf feeding generation of SCB (1SCB) identified in the same mapping population, and assessed the consistency of QTL for 1SWCB across two populations. One hundred seventy-one F2 genotypes from cross CML131 (susceptible) × CML67 (resistant) and 100 RFLP marker loci were used for the QTL analyses. 1SWCB and 1SCB resistance were assessed in F2:3 lines by leaf damage ratings (LDR) after artificial infestation in field experiments with two replications at one subtropical environment in 2 yr. The method of composite interval mapping (CIM) was used for QTL detection. Estimates of genotypic (σ2g) and genotype × year interaction variance (σ2g) were highly significant for 1SWCB LDR and 1SCB LDR. Phenotypic and genotypic correlations between both traits were 0.62 and 1.02, respectively. for 1SWCB LDR, six QTL were detected explaining 53.3% of σ̂2g, with two QTL displaying significant QTL × year interactions. Ten QTL were detected for 1SCB LDR, accounting for 98.2% of σ̂2g. The QTL showed predominantly additive or partially dominant gene action. Seven out of 10 QTL were pleiotropic to both Diatraea spp. Three genomic regions, on Chromosomes 5 and 9, were consistent with a second mapping population derived from cross Ki3 (susceptible) × CML139 (resistant), for which seven QTL for 1SWCB LDR were found. Marker-assisted ‘gene stacking’ is recommended for transferring pleiotropic QTL into susceptible germplasm and for pyramiding QTL from different sources of insect resistance

    New GTC spectroscopic data and a statistical study to better constrain the redshift of the BL Lac RGB J2243 + 203

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    We present new spectroscopic data of the BL Lac RGB 2243 + 203, and its surroundings, obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted in the Gran Telescopio Canarias (GTC). The spectra of neither the BL Lac nor its host galaxy show any spectral feature, thus hindering direct determination of its redshift. The spectroscopic redshift distribution of objects in the MOS field of view shows four galaxies with redshift between 0.5258 and 0.5288. We make use of a statistical analysis to test the possibility that the targeted BL Lac may be a member of that group. By using the spectroscopic redshifts obtained with our GTC observations, we found that this probability is between 86 and 93 per cent.Fil: Rosa González, D. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Muriel, Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mayya, Y. D.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Aretxaga, I.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Becerra González, J.. Instituto de Astrofisica de Canarias; EspañaFil: Carramiñana, Alberto. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Méndez-Abreu, J.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Vega, O. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Terlevich, E-. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Coutiño de León, S.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Furniss, A.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Longinotti, A. L.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Terlevich, R. J.. Instituto Nacional de Astrofísica, Optica y Electrónica; MéxicoFil: Pichel, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Rovero, Adrian Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Donzelli, Carlos Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

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    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review
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