X-ray Emission from an Asymmetric Blast Wave and a Massive White Dwarf in the Gamma-ray Emitting Nova V407 Cyg

Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equilibrium and non-equilibrium ionization plasmas at the time of peak X-ray brightness, indicating a strong asymmetry in the density of the emitting region. Comparing a simple model to the data, we find that the X-ray evolution is broadly consistent with nova ejecta driving a forward shock into the dense wind of the Mira companion. We detect a highly absorbed soft X-ray component in the spectrum during the first 50 days of the outburst that is consistent with supersoft emission from the nuclear burning white dwarf. The high temperature and short turn off time of this emission component, in addition to the observed breaks in the optical and UV lightcurves, indicate that the white dwarf in the binary is extremely massive. Finally, we explore the connections between the X-ray and GeV gamma-ray evolution, and propose that the gamma ray turn-off is due to the stalling of the forward shock as the ejecta reach the red giant surface.Comment: Accepted for publication in ApJ. 17 pages, 9 figure

Na encruzilhada dos saberes e práticas: inserções antropológicas sobre estranhamento e alteridade no interior da Agroecologia.

O objetivo do artigo é apresentar elementos antropológicos que podem contribuir com o processo, já em curso, de edificação da agroecologia como campo de intersecção entre diferentes conhecimentos e práticas. O foco de atenção é a relação entre os agentes de saberes e práticas acadêmicas e os agentes de saberes e práticas locais e etnicamente determinadas. Para tanto, (1) buscamos discutir a incursão teórica da agroecologia sobre a diversidade cultural e suas decorrências práticas; (2) empreendemos uma destilação sobre as principais situações de estranhamento entre técnicos/cientistas e famílias agricultoras; e (3) apresentamos elementos conceituais da antropologia – “cultura”, “alteridade” e “simetria” – que podem contribuir tanto para superação dessas situações de estranhamento, quanto para relações de mútuo aprendizado entre os diferentes sujeitos imersos em contextos agroecológicos

L’eredità del Tenchini come punto di partenza per la ricostruzione della storia di un criminale del XIX secolo

Late in the 19th century, physician Lorenzo Tenchini undertook a study of criminal subjects and psy-chiatric patients. One of these was B.A., a 22-year-old soldier who committed suicide after attempting to kill his lover, a prostitute named G.I. The starting points of this study were the analysis of the subject's biography – data which resulted from the autopsy – and several observations on his brain and skull in accordance with the phrenological doctrine of that time. The goal of this work was to shed new light on an Italian criminal of the late 19th century and on Tenchini's work, combining the material collected by the doctor himself with sources of the period and modern medical knowledge.Alla fine del XIX secolo, il Dottor Lorenzo Tenchini intraprese uno studio su soggetti criminali e pazienti psichiatrici. Uno dei soggetti analizzati era B.A., un soldato di 22 anni che morì dopo aver tentato di uccidere la sua amante, una prostituta di nome G.I. I punti di partenza di questo studio sono stati l'analisi della biografia del soggetto, i dati emersi dall'autopsia e diverse osservazioni riguardanti il suo cervello e il cranio compiute secondo la dottrina frenologica dell'epoca. L'obiettivo di questo studio era di gettare nuova luce su un criminale italiano di fine '800 e sull'opera del Dottor Tenchini, unendo il materiale raccolto dal medico, con fonti dell'epoca e le moderne conoscenze mediche

Possible innovative technical measures for risk prevention during the use of mobile machines with remote guide/control

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Laboratorios Virtuales “LVs” como herramienta de enseñanza aprendizaje de la química a partir del modelo de Resolución de Problemas

El presente estudio se realizó con estudiantes de la Universidad Santo Tomás de Aquino (USTA), de las carreras de Ingeniería Civil, Ambiental y Mecánica, en el espacio académico de Química General y Química Orgánica; quienes en su gran mayoría son apáticos a la química, consideran que los temas son difíciles de entender y no encuentran utilidad a lo que aprenden. Con el fin de mejorar las actitudes de los estudiantes, se elaboraron y aplicaron instrumentos basados en la resolución de problemas, abordando temáticas como gases, titulaciones, aldehídos y cetonas, de manera contextualizada a su entorno y carrera profesional, articulando los laboratorios virtuales (LVs) y los laboratorios tradicionales. Como resultados, y con ayuda de una prueba tipo Likert, medida en criterios como el agrado, motivación, utilidad y grado de conocimiento; se evidenció una mejora en la actitud de los estudiantes, y se mostraron las ventajas y desventajas de trabajar con los LVs

REFLEXIONES SOBRE LA ENSEÑANZA DEL CONCEPTO DE CINÉTICA QUÍMICA EN EDUCACIÓN MEDIA A PARTIR DEL MODELO DE RESOLUCIÓN DE PROBLEMAS1

En este trabajo se muestran algunas de las reflexiones que han tenido lugar en el seminario de Pedagogía y Didáctica III de la Licenciatura en Química en la Universidad Pedagógica Nacional, sobre la importancia que tiene el modelo de resolución de problemas en la enseñanza de las ciencias y particularmente de la química. Se presentan algunas implicaciones pedagógicas y didácticas que tiene el modelo en la enseñanza del concepto de cinética química en educación media, considerando como estrategia metodológica la identificación de ideas previas de los estudiantes y el planteamiento de situaciones problema que difieren de los ejercicios de lápiz y papel. Lo anterior con el fin de generar, desarrollar y fortalecer en los estudiantes cambios conceptuales, actitudinales, metodológicos en torno a la temática

Available Technologies and Commercial Devices to Harvest Energy by Human Trampling in Smart Flooring Systems: a Review

Technological innovation has increased the global demand for electrical power and energy. Accordingly, energy harvesting has become a research area of primary interest for the scientific community and companies because it constitutes a sustainable way to collect energy from various sources. In particular, kinetic energy generated from human walking or vehicle movements on smart energy floors represents a promising research topic. This paper aims to analyze the state-of-art of smart energy harvesting floors to determine the best solution to feed a lighting system and charging columns. In particular, the fundamentals of the main harvesting mechanisms applicable in this field (i.e., piezoelectric, electromagnetic, triboelectric, and relative hybrids) are discussed. Moreover, an overview of scientific works related to energy harvesting floors is presented, focusing on the architectures of the developed tiles, the transduction mechanism, and the output performances. Finally, a survey of the commercial energy harvesting floors proposed by companies and startups is reported. From the carried-out analysis, we concluded that the piezoelectric transduction mechanism represents the optimal solution for designing smart energy floors, given their compactness, high efficiency, and absence of moving parts

Plan4all: European Network of Best Practices for Interoperability of Spatial Planning Information

Methodologies usually adopted in urban and regional planning do not assume an approach based on Spatial Data Infrastructures principles, which could ensure a better use of geospatial data and support interoperability of planning choices providing an active participation of stakeholders involved in planning processes. An innovative approach of e-government based on a better organization and management of geospatial data, could contribute, through a deeper territorial knowledge and a more appropriate use of decision support tools, to more effectively pursue planning goals. Spatial planning and related information have a strategic importance not only at local and national level but also at international scale where a "continuum" of settlements characterizes the crossing of various countries. Planning activity is also strictly related to aspects such as management of natural resources, prevention of natural disasters, transports which in many cases have international cross-border interests. Consequently, today there is an absolute need of harmonized planning data a strong demand of planning core data sets in order to provide an easy and wide understandability of this information. The objective of the Plan4all project is to build a network of local, regional and national stakeholders, companies in the ICT sector, organizations involved in planning and economic development, universities and international agencies in order to find a consensus concerning the harmonization of spatial planning data based on existing best practices in Europe and according to the European Directive INSPIRE. The project takes into account lessons learned from previous experiences, such as Armonia, Humboldt, eSDINet+, Euradin, whose partners are also present in the Plan4all consortium. The project will involve also the experience of OGC working group members concerning the definition of standards technologies. Plan4all aims to contribute to the harmonization of planning data. Based on best practi- - ces analysis, the project is producing a series of technical documents for metadata profiles design and implementation, data models and harmonization procedures. Particular attention will be paid to issues related to the protection of intellectual property rights, as well as security aspects

In silico characterization of nanoparticles

Nanoparticles (NPs) make for intriguing heterogeneous catalysts due to their large active surface area and excellent and often size-dependent catalytic properties that emerge from a multitude of chemically different surface reaction sites. NP catalysts are, in principle, also highly tunable: even small changes to the NP size or surface facet composition, doping with heteroatoms, or changes of the supporting material can significantly alter their physicochemical properties. Because synthesis of size- and shape-controlled NP catalysts is challenging, the ability to computationally predict the most favorable NP structures for a catalytic reaction of interest is an in-demand skill that can help accelerate and streamline the material optimization process. Fundamentally, simulations of NP model systems present unique challenges to computational scientists. Not only must considerable methodological hurdles be overcome in performing calculations with hundreds to thousands of atoms while retaining appropriate accuracy to be able to probe the desired properties. Also, the data generated by simulations of NPs are typically more complex than data from simulations of, for example, single crystal surface models, and therefore often require different data analysis strategies. To this end, the present work aims to review analytical methods and data analysis strategies that have proven useful in extracting thermodynamic trends from NP simulations

Simulations of the Oxidation and Degradation of Platinum Electrocatalysts

Improved understanding of the fundamental processes leading to degradation of platinum nanoparticle electrocatalysts is essential to the continued advancement of their catalytic activity and stability. To this end, the oxidation of platinum nanoparticles is simulated using a ReaxFF reactive force field within a grand‐canonical Monte Carlo scheme. 2–4 nm cuboctahedral particles serve as model systems, for which electrochemical potential‐dependent phase diagrams are constructed from the thermodynamically most stable oxide structures, including solvation and thermochemical contributions. Calculations in this study suggest that surface oxide structures should become thermodynamically stable at voltages around 0.80–0.85 V versus standard hydrogen electrode, which corresponds to typical fuel cell operating conditions. The potential presence of a surface oxide during catalysis is usually not accounted for in theoretical studies of Pt electrocatalysts. Beyond 1.1 V, fragmentation of the catalyst particles into [Pt$_{6}$O$_{8}$]$^{4-}$ clusters is observed. Density functional theory calculations confirm that [Pt$_{6}$O$_{8}$]$^{4-}$ is indeed stable and hydrophilic. These results suggest that the formation of [Pt$_{6}$O$_{8}$]$^{4-}$ may play an important role in platinum catalyst degradation as well as the electromotoric transport of Pt$^{2+/4+Zahl}$ ions in fuel cells