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

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

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

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

Software variability composition and abstraction in robot control systems

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

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

Molecular aspects of Homozygous Familial Hypercholesterolemia in Iberoamerican Countries

Homozygous Familial Hypercholesterolemia (HoFH) is a rare disorder, affecting 1 in 300,000 to 1,000,000 people in the general population. The Iberoamerican FH (IBAFH) network was constituted in 2013 with the main objectives to promote awareness and education on FH, and to improve and promote early diagnosis and treatment of the disorder in the network countries. In 2018, there are 8 countries (Argentina, Brazil, Chile, Colombia, Mexico, Portugal, Spain and Uruguay) belonging to the network representing 75% of region’s population. It is estimated that there are 600 to 1,800 HoFH in the Ibero-America, most of them not diagnosed and/or not treated adequately. The Iberoamerican community has an estimated population of 640 million inhabitants. The objective of this work is to describe molecular characteristics of HoFH diagnosis in Argentina, Brazil, Chile, Colombia, Mexico, Portugal, Spain, and Uruguay.N/

Viscoelasticity of Graphite Oxide-Based Suspensions in PDMS

International audienceThe visco elastic behavior of graphite oxide-loaded PDMS suspensions showed, at low frequencies, a dominant elastic behavior with the appearance of a secondary plateau above 1.5 wt %. Within the investigated concentrations, such behavior was not observed for the graphite and functionalized graphite oxide/PDMS suspensions. This low percolation threshold of GO sheets was attributed to a macroscale aggregation. Furthermore, the critical strain (transition between the linear and nonlinear regime) was observed to slightly s. depend on the particle concentration (gamma(c) proportional to phi(-1 +/- 0.2)) Consequently, the exponent x (x = 0.4), related to the filler volume fraction and the aggregate structure, is lower than 1. This result means that a fractal structure cannot be associated with the aggregation of GO sheets. Actually, GO sheets aggregate into agglomerates that span through the gap between the plates of the rheometer. Agglomeration of GO sheets without any fractal structure explains this particular behavior. Furthermore, recovery tests consisting of subsequent strain sweep tests proved that the initial equilibrium network can be totally and rapidly restored. This particular behavior originates from the low viscosity of the PDMS suspension allowing Brownian motion of graphene oxide sheets to occur within only a few seconds