23 research outputs found

    Crop residue grazing and tillage systems effects on soil physical properties and corn (Zea Mays L.) performance

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    Crop-livestock systems under no till (NT) could negatively affect soil physical properties and crop performance, due to the additive effects of reduced soil cover and cattle trampling due to livestock grazing, and the absence of tillage. We evaluated the effects of four grazing strategies and of a shallow tillage (ST) on soil physical properties and corn (Zea mays L.) performance for a mollisol after 15 years under crop-livestock systems under NT in Argentina. Grazing strategies evaluated were: closure (C), one grazing (OG), high stocking rate (HR) and farmer's management (FM), and the tillage systems were: NT and ST. Bulk density (BD), penetration resistance (PR), hydraulic conductivity (ks), plant population, surface root distribution, aboveground dry matter accumulation, aboveground total N (TN) accumulation and corn yield were evaluated. High stocking rate and FM increased RP. On the other hand, ST decreased PR and BD and increased ks. Corn yield was higher under ST than under NT, and under HR than under the other grazing strategies. Total N accumulation was higher under HR than under the rest of grazing strategies. Rational grazing management and use of tillage systems on resilient soils could have prevented soil physical properties be affected beyond critical thresholds.Facultad de Ciencias Agrarias y Forestale

    UHMWPE/HDPE in-reactor blends, prepared by in situ polymerization: synthetic aspects and characterization

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    This work covers the synthesis and characterization of in-reactor Ultra-High Molecular Weight Polyethylene/ High Density Polyethylene, UHMWPE/HDPE, blends by in situ polymerization in a single reactor, through dual catalyst immobilization. These blends are synthesized combining two different catalysts (one for each targeted molar mass) co-immobilized in mesoporous Santa Barbara Amorphous, SBA-15, particles. First, the ethylene polymerization behavior is investigated, under different polymerization conditions. Then, studies on the thermal, mechanical and rheological characteristics of the produced in-reactor blends are presented and their performance is compared and discussed in a comprehensive way. Moreover, the effect of different filler contents on the properties exhibited by the resulting materials is investigated. Results have shown that these in-reactor UHMWPE/HDPE blends exhibit a complex thermal, mechanical and rheological behavior, which depends mainly on the proportion between the two polymer components and on the amount of SBA-15.info:eu-repo/semantics/publishedVersio

    Crop residue grazing and tillage systems effects on soil physical properties and corn (Zea Mays L.) performance

    Get PDF
    Crop-livestock systems under no till (NT) could negatively affect soil physical properties and crop performance, due to the additive effects of reduced soil cover and cattle trampling due to livestock grazing, and the absence of tillage. We evaluated the effects of four grazing strategies and of a shallow tillage (ST) on soil physical properties and corn (Zea mays L.) performance for a mollisol after 15 years under crop-livestock systems under NT in Argentina. Grazing strategies evaluated were: closure (C), one grazing (OG), high stocking rate (HR) and farmer's management (FM), and the tillage systems were: NT and ST. Bulk density (BD), penetration resistance (PR), hydraulic conductivity (ks), plant population, surface root distribution, aboveground dry matter accumulation, aboveground total N (TN) accumulation and corn yield were evaluated. High stocking rate and FM increased RP. On the other hand, ST decreased PR and BD and increased ks. Corn yield was higher under ST than under NT, and under HR than under the other grazing strategies. Total N accumulation was higher under HR than under the rest of grazing strategies. Rational grazing management and use of tillage systems on resilient soils could have prevented soil physical properties be affected beyond critical thresholds.Facultad de Ciencias Agrarias y Forestale

    Crop residue grazing and tillage systems effects on soil physical properties and corn (Zea Mays L.) performance

    Get PDF
    Crop-livestock systems under no till (NT) could negatively affect soil physical properties and crop performance, due to the additive effects of reduced soil cover and cattle trampling due to livestock grazing, and the absence of tillage. We evaluated the effects of four grazing strategies and of a shallow tillage (ST) on soil physical properties and corn (Zea mays L.) performance for a mollisol after 15 years under crop-livestock systems under NT in Argentina. Grazing strategies evaluated were: closure (C), one grazing (OG), high stocking rate (HR) and farmer's management (FM), and the tillage systems were: NT and ST. Bulk density (BD), penetration resistance (PR), hydraulic conductivity (ks), plant population, surface root distribution, aboveground dry matter accumulation, aboveground total N (TN) accumulation and corn yield were evaluated. High stocking rate and FM increased RP. On the other hand, ST decreased PR and BD and increased ks. Corn yield was higher under ST than under NT, and under HR than under the other grazing strategies. Total N accumulation was higher under HR than under the rest of grazing strategies. Rational grazing management and use of tillage systems on resilient soils could have prevented soil physical properties be affected beyond critical thresholds.Facultad de Ciencias Agrarias y Forestale

    Phenotypical, Clinical, and Molecular Aspects of Adults and Children With Homozygous Familial Hypercholesterolemia in Iberoamerica

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    Fil: Alves, Ana Catarina. Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisboa; Portugal.Fil: Alonso, Rodrigo. Center for Advanced Metabolic Medicine and Nutrition, Santiago; Chile.Fil: Diaz-Diaz, José Luís. Hospital Universitario A Coruña. Department of Internal Medicine; España.Fil: Medeiros, Ana Margarida. Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisboa; Portugal.Fil: Jannes, Cinthia E. University of São Paulo. Medical School. Hospital São Paulo. Heart Institute (InCor); Brasil.Fil: Merchan, Alonso. Fundación Clinica SHAIO, Cardiología, Bogotá; Colombia.Fil: Vasques-Cardenas, Norma A. Universidad Autónoma de Guadalajara. Facultad de Medicina Zapopan; México.Fil: Cuevas, Ada. Center for Advanced Metabolic Medicine and Nutrition, Santiago; Chile.Fil: Chacra, Ana Paula. University of São Paulo. Medical School. Hospital São Paulo. Heart Institute (InCor); Brasil.Fil: Krieger, Jose E. University of São Paulo. Medical School. Hospital São Paulo. Heart Institute (InCor); Brasil.Fil: Arroyo, Raquel. Fundación Hipercolesterolemia Familiar, Madrid; España.Fil: Arrieta, Francisco. Hospital Ramón y Cajal. Departamento de Endocrinología, Madrid; España.Fil: Schreier, Laura. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica, Laboratorio de Lípidos y Aterosclerosis; Argentina.Fil: Corral, Pablo. Universidad FASTA. Facultad de Medicina. Cátedra Farmacología e Investigación, Mar del Plata; Argentina.Fil: Bañares, Virginia. ANLIS Dr.C.G.Malbrán. Centro Nacional de Genética Médica. Departamento de Genética Experimental; Argentina.Fil: Araujo, Maria B. Hospital Garrahan. Servicio de Nutrición; Argentina.Fil: Bustos, Paula. Universidad de Concepción. Facultad de Farmacia; Chile.Fil: Asenjo, Sylvia. Universidad de Concepción. Facultad de Medicina; Chile.Fil: Stoll, Mario. Programa GENYCO, Laboratorio de Genética Molecular. Comisión Honoraria de Salud Cardiovascular, Montevideo; Uruguay.Fil: Dell'Oca, Nicolás. Programa GENYCO, Laboratorio de Genética Molecular. Comisión Honoraria de Salud Cardiovascular, Montevideo; Uruguay.Fil: Reyes, Maria. Fundación Cardiovascular de Colombia. Cardiología; Bogotá.Fil: Ressia, Andrés. Fundación Cardiovascular de Colombia. Cardiología; Bogotá.Fil: Campo, Rafael. Instituto Mexicano del Seguro Social. Centro de Investigación Biomédica del Occidente, Guadalajara; México.Fil: Magaña-Torres, Maria T. Instituto Nacional de Ciencias Médicas y Nutrición. Unidad de Investigación de Enfermedades Metabólicas; México.Fil: Metha, Roopa. Instituto Nacional de Ciencias Médicas y Nutrición. Unidad de Investigación de Enfermedades Metabólicas; México.Fil: Aguilar-Salinas, Carlos A. Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Departamento de Endocrinología y Metabolismo. Secretaría de la Defensa Nacional. Unidad de Especialidades Médicas. Servicio de Endocrinología; México.Fil: Ceballos-Macias, José J. Pontificia Universidad Javerina. Facultad de Medicina. Departamento de Medicina Interna, Bogotá; Colombia.Fil: Ruiz Morales, Álvaro J. Pontificia Universidad Javerina. Facultad de Medicina. Departamento de Medicina Interna, Bogotá; Colombia.Fil: Mata, Pedro. Fundación Hipercolesterolemia Familiar, Madrid; España.Fil: Bourbon, Mafalda. Instituto Nacional de Saúde Doutor Ricardo Jorge, Lisboa; Portugal.Fil: Santos, Raul D. University of São Paulo. Medical School. Hospital São Paulo. Heart Institute (InCor); Brasil.OBJECTIVE: Characterize homozygous familial hypercholesterolemia (HoFH) individuals from Iberoamerica. APPROACH AND RESULTS: In a cross-sectional retrospective evaluation 134 individuals with a HoFH phenotype, 71 adults (age 39.3±15.8 years, 38.0% males), and 63 children (age 8.8±4.0 years, 50.8% males) were studied. Genetic characterization was available in 129 (96%). The majority (91%) were true homozygotes (true HoFH, n=79, 43.0% children, 46.8% males) or compound heterozygotes (compound heterozygous familial hypercholesterolemia, n=39, 51.3% children, 46.2% males) with putative pathogenic variants in the LDLR. True HoFH due to LDLR variants had higher total (P=0.015) and LDL (low-density lipoprotein)-cholesterol (P=0.008) compared with compound heterozygous familial hypercholesterolemia. Children with true HoFH (n=34) tended to be diagnosed earlier (P=0.051) and had a greater frequency of xanthomas (P=0.016) than those with compound heterozygous familial hypercholesterolemia (n=20). Previous major cardiovascular events were present in 25 (48%) of 52 children (missing information in 2 cases), and in 43 (67%) of 64 adults with LDLR variants. Children who are true HoFH had higher frequency of major cardiovascular events (P=0.02), coronary heart (P=0.013), and aortic/supra-aortic valve diseases (P=0.022) than compound heterozygous familial hypercholesterolemia. In adults, no differences were observed in major cardiovascular events according to type of LDLR variant. From 118 subjects with LDLR variants, 76 (64%) had 2 likely pathogenic or pathogenic variants. In 89 subjects with 2 LDLR variants, those with at least one null allele were younger (P=0.003) and had a greater frequency of major cardiovascular events (P=0.038) occurring at an earlier age (P=0.001). CONCLUSIONS: There was a high frequency of cardiovascular disease even in children. Phenotype and cardiovascular complications were heterogeneous and associated with the type of molecular defect

    Software variability composition and abstraction in robot control systems

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    Control systems for autonomous robots are concurrent, distributed, embedded, real-time and data intensive software systems. A real-world robot control system is composed of tens of software components. For each component providing robotic functionality, tens of different implementations may be available. The difficult challenge in robotic system engineering consists in selecting a coherent set of components, which provide the functionality required by the application requirements, taking into account their mutual dependencies. This challenge is exacerbated by the fact that robotics system integrators and application developers are usually not specifically trained in software engineering. Current approaches to variability management in complex software systems consists in explicitly modeling variation points and variants in software architectures in terms of Feature Models. The main contribution of this paper is the definition of a set of models and modeling tools that allow the hierarchical composition of Feature Models, which use specialized vocabularies for robotic experts with different skills and expertise

    On the Dichotomy of Debugging Behavior Among Programmers

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    Debugging is an inevitable activity in most software projects, often difficult and more time-consuming than expected, giving it the nickname the “dirty little secret of computer science.” Surprisingly, we have little knowledge on how software engineers debug software problems in the real world, whether they use dedicated debugging tools, and how knowledgeable they are about debugging. This study aims to shed light on these aspects by following a mixed-methods research approach. We conduct an online survey capturing how 176 developers reflect on debugging. We augment this subjective survey data with objective observations on how 458 developers use the debugger included in their integrated development environments (IDEs) by instrumenting the popular ECLIPSE and INTELLIJ IDEs with the purpose-built plugin WATCHDOG 2.0. To clarify the insights and discrepancies observed in the previous steps, we followed up by conducting interviews with debugging experts and regular debugging users. Our results indicate that IDE-provided debuggers are not used as often as expected, because “printf debugging” remains a feasible choice for many programmers. Furthermore, both knowledge and use of advanced debugging features are low. Our results call for strengthening hands-on debugging experience in computer science curricula and have already refined the implementation of modern IDE debuggers.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Software Engineerin
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