HESS J1632-478: an energetic relic

HESS J1632-478 is an extended and still unidentified TeV source in the galactic plane. In order to identify the source of the very high energy emission and to constrain its spectral energy distribution, we used a deep observation of the field obtained with XMM-Newton together with data from Molonglo, Spitzer and Fermi to detect counterparts at other wavelengths. The flux density emitted by HESS J1632-478 peaks at very high energies and is more than 20 times weaker at all other wavelengths probed. The source spectrum features two large prominent bumps with the synchrotron emission peaking in the ultraviolet and the external inverse Compton emission peaking in the TeV. HESS J1632-478 is an energetic pulsar wind nebula with an age of the order of 10^4 years. Its bolometric (mostly GeV-TeV) luminosity reaches 10% of the current pulsar spin down power. The synchrotron nebula has a size of 1 pc and contains an unresolved point-like X-ray source, probably the pulsar with its wind termination shock.Comment: A&A accepted, 9 pages, 5 figures, 4 table

Evaluating quality in online asynchronous interactions between students and discussion facilitators

Online discussion forums have become an essential part of university courses, whether the course is conducted online, or face to face, or in mixed or blended mode. Discussion forums are considered to engage students better with the course content and encourage them to share and gain knowledge from each other. However, online engagement does not always happen automatically between students. Hence grading of discussion forum participation has been recommended to ensure quality student participation. Currently, a major focus has been put onto the better use of discussion forums, but the way in which the quality of participation can be evaluated has yet to be adequately investigated. Furthermore, evaluation of the instructor participation in a discussion forum and its impact on students and their contributions is lacking. In this paper, we report on our research into online discussion forum quality through analysis of discussion forum activities, along with student focus group meetings and instructor interviews. We have devised a set of criteria for evaluating discussion forum activities. Our results show that students depend highly on the instructor's feedback and the participation of the students can only be evaluated with reference to the moderation of the instructors

I reinterventi nell’iperparatiroidismo

reinterventi in chirurgia paratiroidea rappresentano una sfida impegnativa per il chirurgo che deve valutare attentamente i dati operatori e istologici del primo intervento, usare una diagnostica accurata preoperatoria con ecografia e scintigrafia con sestamibi e avere ben presente l’anatomia e l’embriologia delle ghiandole paratiroidee. Elementi fondamentali per ottenere un successo chirurgico sono l’uso del dosaggio intraoperatorio del paratormone e una grande esperienza del chirurgo. Seguendo tali principi si arriva a ottenere una remissione del quadro iperparatiroideo nell’85-90% per l’HPT I e nel 70% per l’HPT II e III. Gli Autori presentano la loro casistica di 75 reinterventi dopo HPT I e di 85 reinterventi dopo HPT II e III, su una casistica totale di 2072 interventi di paratiroidectomia eseguiti fra gennaio 1975 e ottobre 2009

Analysis of Petri Net Models through Stochastic Differential Equations

It is well known, mainly because of the work of Kurtz, that density dependent Markov chains can be approximated by sets of ordinary differential equations (ODEs) when their indexing parameter grows very large. This approximation cannot capture the stochastic nature of the process and, consequently, it can provide an erroneous view of the behavior of the Markov chain if the indexing parameter is not sufficiently high. Important phenomena that cannot be revealed include non-negligible variance and bi-modal population distributions. A less-known approximation proposed by Kurtz applies stochastic differential equations (SDEs) and provides information about the stochastic nature of the process. In this paper we apply and extend this diffusion approximation to study stochastic Petri nets. We identify a class of nets whose underlying stochastic process is a density dependent Markov chain whose indexing parameter is a multiplicative constant which identifies the population level expressed by the initial marking and we provide means to automatically construct the associated set of SDEs. Since the diffusion approximation of Kurtz considers the process only up to the time when it first exits an open interval, we extend the approximation by a machinery that mimics the behavior of the Markov chain at the boundary and allows thus to apply the approach to a wider set of problems. The resulting process is of the jump-diffusion type. We illustrate by examples that the jump-diffusion approximation which extends to bounded domains can be much more informative than that based on ODEs as it can provide accurate quantity distributions even when they are multi-modal and even for relatively small population levels. Moreover, we show that the method is faster than simulating the original Markov chain

IGR J11014-6103: a newly discovered pulsar wind nebula?

Context: IGRJ11014-6103 is one of the still unidentified hard X-ray INTEGRAL sources, reported for the first time in the 4th IBIS/ISGRI catalog. Aims: We investigated the nature of IGR J11014-6103 by carrying out a multiwavelength analysis of the available archival observations performed in the direction of the source. Methods: We present first the results of the timing and spectral analysis of all the X-ray observations of IGR J11014-6103 carried out with ROSAT, ASCA, Einstein, Swift, and XMM-Newton, and then use them to search for possible counterparts to the source in the optical, infra-red, radio and gamma-ray domain. Results: Our analysis revealed that IGR J11014-6103 is comprised of three different X-ray emitting regions: a point-like source, an extended object and a cometary-like "tail" (~4 arcmin). A possible radio counterpart positionally coincident with the source was also identified. Conclusions: Based on these results, we suggest that the emission from IGR J11014-6103 is generated by a pulsar wind nebula produced by a high-velocity pulsar. IGR J11014-6103 might be the first of these systems detected with INTEGRAL IBIS/ISGRI.Comment: A&A accepted, 8 pages, 8 figures, 2 table

China and the art of (technological) war

China se encamina a convertirse en una potencia tecnológica a mediados del siglo XXI. Este proceso se funda sobre cuatro pilares: sostenido incremento del presupuesto asignado al desarrollo científico-tecnológico, su directa vinculación con estrategias de innovación a fin de aumentar la productividad y sostener competitividad exportadora, creación e internacionalización de firmas tecnológicas, y expectativas gubernamentales por cerrar las brechasde conocimiento aún existentes que separan a China de competidores asiáticos y occidentales. A lo largo de cuatro décadas, las reformas pro mercado confirman esta senda de transformación y generación de capacidades en sectores tecnológicos de punta. La competencia estratégica con Estados Unidos acelera esta carrera y confirma objetivos sobre posicionamiento de firmas tecnológicas chinas como líderes en inteligencia artificial (IA), telecomunicaciones y redes 5G.China is on the wayto become a technological power in the mid-21st Century. This process is based on four pillars: sustained increase in science and technology development budget allocations, its direct link to innovation strategies to increase productivity and up-keep exploration competitiveness, high-tech firm creation and internationalization, and national goals aimed at closing the gap between domestic S&T capacities and those of the more advanced developed Asian and Western economies. Over four decades, pro-market reforms have confirmed this path, towards transformation and capacity building in cutting edge technological sectors. Strategic tensions with the United States speed up this race and confirm China's national goals for its companies to take the lead in artificial intelligence (AI), telecommunications and 5G networks.Instituto de Relaciones Internacionale

Resilience of small-scale societies: a view from drylands.

To gain insights on long-term social-ecological resilience, we examined adaptive responses of small-scale societies to dryland-related hazards in different regions and chronological periods, spanning from the mid-Holocene to the present. Based on evidence from Africa (Sahara and Sahel), Asia (south margin of the Thar desert), and Europe (South Spain), we discuss key traits and coping practices of small-scale societies that are potentially relevant for building resilience. The selected case studies illustrate four main coping mechanisms: mobility and migration, storage, commoning, and collective action driven by religious beliefs. Ultimately, the study of resilience in the context of drylands emphasizes the importance of adaptive traits and practices that are distinctive of small-scale societies: a strong social-ecological coupling, a solid body of traditional ecological knowledge, and a high degree of internal cohesion and self-organization.SP2016http://www.ecologyandsociety.org/vol21/iss2/art53