3,361 research outputs found
Armed Conflict Exposure, Human Capital Investments and Child Labor: Evidence from Colombia
Using a unique combination of household and violence data sets and a duration analysis methodology, this paper estimates the effect that exposure to armed conflict has on school drop-out decisions of Colombian children between the ages of six and seventeen. After taking into account the possible endogeneity of municipal conflict related events through the use of instrumental variables, we find that armed conflict reduces the average years of schooling in 8.78% for all Colombian children. This estimate increases to 17.03% for children between sixteen and seventeen years old. We provide evidence that such effect may be induced mainly through higher mortality risks, and to lesser extent due to negative economic shocks and lower school quality; all of which induce a trade-off between schooling and child labor.Armed con.ict, School drop-out, Duration Analysis, Colombia
Plan de adaptación aplicado para proyectos de desarrollo de software: caso de estudio
El estudio se inicia destacando la importancia del uso de estándares de calidad, respeto por el medio ambiente y la seguridad en el ambiente laboral. Luego se describen las metodologías empleadas por la empresa bajo estudio a partir de la descripción de sus herramientas de gestión, integración y adaptación, siendo esta última el objetivo de este trabajo. Al hacer comparaciones entre lo recomendado por los estándares y lo que hace la empresa bajo estudio, se hace evidente que para gerenciar proyectos de software deben seguirse los lineamientos de forma que estos se adapten a los requerimientos y objetivos del proyecto y no lo contrario
Decentralized trust in the inter-domain routing infrastructure
Inter-domain routing security is of critical importance to the Internet since it prevents unwanted traffic redirections. The current system is based on a Public Key Infrastructure (PKI), a centralized repository of digital certificates. However, the inherent centralization of such design creates tensions between its participants and hinders its deployment. In addition, some technical drawbacks of PKIs delay widespread adoption. In this paper we present IPchain, a blockchain to store the allocations and delegations of IP addresses. IPchain leverages blockchains' properties to decentralize trust among its participants, with the final goal of providing flexible trust models that adapt better to the ever-changing geopolitical landscape. Moreover, we argue that Proof of Stake is a suitable consensus algorithm for IPchain due to the unique incentive structure of this use-case, and that blockchains offer relevant technical advantages when compared to existing systems, such as simplified management. In order to show its feasibility and suitability, we have implemented and evaluated IPchain's performance and scalability storing around 350k IP prefixes in a 2.5 GB chain.Peer ReviewedPostprint (published version
Algunos aspectos de la actividad eléctrica en el tejido cardiaco utilizando elementos finitos
En el siglo pasado fueron muchos los avances que se dieron en las ciencias biológicas, en particular, en la fisiología humana con la utilización de los modelos matemáticos para acercarnos a la comprensión de su fenomenología fisiológica, en especial con las ecuaciones diferenciales tanto las ordinarias como las parciales. Sólo por mencionar algunos de los principales investigadores en este campo tenemos a Hodkin y Huxley en (1952), [25, 26, 27, 29]; FitzHugh-Nagumo (1961), Hirota, Satsamo (1987), quienes han colaborado con una serie de modelos matemáticos de gran aplicabilidad en la fisiología humana, mostrando el acercamiento con otras disciplinas de las ciencias exactas para la interpretación y esclarecimiento del fenómeno afrontado. Los avances en la computación hacen posible simulaciones en tiempo real de los fenómenos y esclarecer los procesos óptimos que utiliza la fisiología para completar sus procesos funcionales [19].iv, 80 p.Contenido parcial: Fisiología del corazón -- La dinámica de las células excitables -- El modelo Hodgkin-Huxley -- La actividad eléctrica del tejido cardiaco -- El método de los elementos finitos
Mining and quality assessment of mashup model patterns with the crowd: A feasibility study
Pattern mining, that is, the automated discovery of patterns from data, is a mathematically complex and computationally demanding problem that is generally not manageable by humans. In this article, we focus on small datasets and study whether it is possible to mine patterns with the help of the crowd by means of a set of controlled experiments on a common crowdsourcing platform. We specifically concentrate on mining model patterns from a dataset of real mashup models taken from Yahoo! Pipes and cover the entire pattern mining process, including pattern identification and quality assessment. The results of our experiments show that a sensible design of crowdsourcing tasks indeed may enable the crowd to identify patterns from small datasets (40 models). The results, however, also show that the design of tasks for the assessment of the quality of patterns to decide which patterns to retain for further processing and use is much harder (our experiments fail to elicit assessments from the crowd that are similar to those by an expert). The problem is relevant in general to model-driven development (e.g., UML, business processes, scientific workflows), in that reusable model patterns encode valuable modeling and domain knowledge, such as best practices, organizational conventions, or technical choices, that modelers can benefit from when designing their own models
Antibiotic prophylaxis habits in dental implant surgery among dentists in Spain. A cross-sectional survey
The use of antibiotics to prevent dental implant failures and postoperative infections remains a controversial issue. The objectives of this study were to assess the current antibiotic prescribing patterns and antibiotic prescribing frequency of dentists in Biscay (Spain) in conjunction with routine dental implant surgery among healthy patients and to determine whether any consensus has been reached by such practitioners and last published evidence was being followed. Observational cross-sectional study: electronic survey. This study was reported according to the STROBE guidelines. This anonymous questionnaire contained open-ended and close-ended questions. An email was sent 26 October 2017 to all the registered members of the Biscay dentists? College (n=989). The collected data were analyzed using STATA® 14 software, and 95% confidence intervals (CI) were used to assess the frequency of prescription for each antibiotic regimen. The survey was responded to by a total of 233 participants (response rate=23.56%). Overall, 210 participants finished the survey completely, and 23 surveys were answered partially. The questionnaire was responded to by 122 females (58.1%) and 88 males (41.9%). Of the participants, 88% (n=207) always routinely prescribed prophylactic antibiotics in conjunction with dental implant surgery (95% CI: 84.79-92.88%). Approximately 9% (n=22) prescribed antibiotics sometimes (95% CI: 5.68-13.19%), and only 4 dentists (1.72%) never prescribed antibiotics (95% CI: 0.04-3.38%). Overall, 179 of 233 respondents prescribed both pre- and postoperative antibiotics (78.85%, 95% CI: 72.96-83.97%), 13 prescribed antibiotics only preoperatively (5.73%, 95% CI: 3.08-9.59%), and 35 prescribed antibiotics exclusively after routine dental implant surgery (15.42%, 95% CI: 10.98-20.78%). Most of the dentists working in Biscay routinely prescribe prophylactic antibiotics in conjunction with dental implant surgery among healthy patients. A large range of prophylactic regimens are prescribed and the most recently published evidence is not being followed
Global state, local decisions: Decentralized NFV for ISPs via enhanced SDN
The network functions virtualization paradigm is rapidly gaining interest among Internet service providers. However, the transition to this paradigm on ISP networks comes with a unique set of challenges: legacy equipment already in place, heterogeneous traffic from multiple clients, and very large scalability requirements. In this article we thoroughly analyze such challenges and discuss NFV design guidelines that address them efficiently. Particularly, we show that a decentralization of NFV control while maintaining global state improves scalability, offers better per-flow decisions and simplifies the implementation of virtual network functions. Building on top of such principles, we propose a partially decentralized NFV architecture enabled via an enhanced software-defined networking infrastructure. We also perform a qualitative analysis of the architecture to identify advantages and challenges. Finally, we determine the bottleneck component, based on the qualitative analysis, which we implement and benchmark in order to assess the feasibility of the architecture.Peer ReviewedPostprint (author's final draft
One swallow does not make a summer : episodes and persistence in high growth
This paper analyzes firms' episodes (spells) of high growth (HG) using a sample of Spanish manufacturing firms observed over two decades. The use of duration models allows us to investigate the following: (i) the probability of experiencing HG episodes, (ii) persistence in HG, and (iii) the determinants of the transitions in and out of the HG state and whether their impact varies over the business cycle. We find that about half of the firms experience at least one HG episode, but they seldom experience more than one. Moreover, high-growth status is rarely repeated due to high first-year selection. Yet, in subsequent years beyond the first one, the hazard rate from HG status falls substantially. These results suggest an "episodic" nature of HG and further allow us to identify two groups of firms characterized by the following: (i) (relatively) long HG spells and short no high-growth (NHG) spells and (ii) short HG spells and long NHG spells. In addition, some firm and market (demand) characteristics increase the probability of becoming an HG firm and enhancing HG persistence. Finally, during the downturn, the role of younger age and smaller size in explaining HG decreases
Valorisation of history and landscape for promoting the memory of WWI
10 p.In recent years many activities were conducted to commemorate the 100th Anniversary of the FirstWorld War (WWI) outbreak. Among these, the valorisation of history and landscape (VAST) project(http://vast.fbk.eu) was part of the initiatives promoted by the Autonomous Province of Trento (Italy)as a tribute to WWI events in the region. The project was primarily aimed to document and promote,through 3D digitization approaches, ICT technologies and communication material, the memory of sites,theatre of the world conflict. The Trento’s area was under the Austro-Hungarian Empire until the end ofWWI and on the border with the Italian Kingdom. The area represented a crucial and bloody war frontbetween the Austrian and Italian territories. It was thus constellated of military fortresses, trenches andtunnels, most of them now ruined and at risk to slowly disappear. 3D surveying and modelling techniqueswere exploited to produce 3D digital models of structures and objects, along with virtual tours, dissem-ination material and a WebGIS of the area. All the products are now used for restoration, valorisation,educational and communication purposesS
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