868 research outputs found

    Un análisis experimental de dos anuncios políticos, racional y emocional

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    En su afán por conquistar el poder, los candidatos a posiciones políticas han estado procurando la preferencia de los electores mediante técnicas de venta que se originaron en las empresas comerciales, como propaganda, eventos de relaciones públicas, patrocinios, etc. Esto significa las más de las veces estar presente en los medios masivos, intentar presentarse bajo su mejor cara, y minimizar u ocultar las propias desventajas. La manipulación interesada de los ciudadanos con fines electorales la considero como una inquietud disciplinaria de la Ciencias Sociales, en particular de la Ciencia Política. Este trabajo pretende contribuir al conocimiento de la relación entre dos tipos de mensaje y el sentido del voto por parte del ciudadano. La diferencia entre ambos mensajes estudiados consiste en que se disecan en racional y emocional para efectos de comprensión, pero se comportan orgánicamente en la toma de decisiones, tendiendo a predominar una de las dos causas. Para fines de este estudio, se trató de producir estímulos tan diferentes como fuera posible, cargados de notas emocionales o racionales. Se reconoce empero que en el comportamiento humano ninguno ocurre en forma pura, sino que ambos se combinan cuando tomamos decisiones

    Resolution of Linear Algebra for the Discrete Logarithm Problem Using GPU and Multi-core Architectures

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    In cryptanalysis, solving the discrete logarithm problem (DLP) is key to assessing the security of many public-key cryptosystems. The index-calculus methods, that attack the DLP in multiplicative subgroups of finite fields, require solving large sparse systems of linear equations modulo large primes. This article deals with how we can run this computation on GPU- and multi-core-based clusters, featuring InfiniBand networking. More specifically, we present the sparse linear algebra algorithms that are proposed in the literature, in particular the block Wiedemann algorithm. We discuss the parallelization of the central matrix--vector product operation from both algorithmic and practical points of view, and illustrate how our approach has contributed to the recent record-sized DLP computation in GF(28092^{809}).Comment: Euro-Par 2014 Parallel Processing, Aug 2014, Porto, Portugal. \<http://europar2014.dcc.fc.up.pt/\&gt

    Estratégia competitiva de uma multinacional estrangeira na avicultura de postura no Brasil.

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    Este estudo aborda a questão das estratégias envolvidas no processo de importação de gaiolas para aves de postura, direcionadas ao centro de distribuição de uma multinacional estrangeira localizada em Araraquara, São Paulo. Identifica as razões que levam uma empresa multinacional a aumentar seus investimentos no Brasil, onde está implantando um centro de distribuição (CD). Para estudar as estratégias envolvidas no processo, realizou-se pesquisa exploratória sobre o atual processo logístico da empresa, buscando identificar tais estratégias e as vantagens do novo processo. O trabalho apoia-se nas cinco forças competitivas de Porter, na análise SWOT, nas estratégias genéricas adotadas para obtenção de retorno sobre os investimentos e ainda, fundamenta-se em temas como, importação, logística, armazenagem e centro de distribuição. A pesquisa demonstra que a implantação do CD envolve a estratégia de inserção do produto no mercado nacional, especificamente em São Paulo, onde está o maior mercado de aves de postura do País. Para obter vantagem competitiva, a multinacional adota ainda a estratégia genérica da diferenciação, com foco em tecnologia e qualidade do produto. Apesar dos altos custos da construção e manutenção do CD representarem uma barreira de entrada no mercado, o investimento não representa risco financeiro, já que aumentará a demanda pelo produto, resultando maior retorno sobre o capital investido

    Consequences of the ion beam irradiation on the chemical durability of thorium phosphate diphosphate – kinetics study

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    RADIOCHIn the field of the long-term specific immobilization of actinides, thorium phosphate diphosphate (β-TPD), as potential candidate, must respond to several criteria. Among them, the material must present a good resistance to irradiation and keep its initial good properties such as resistance to aqueous alteration. In order to check this later point, sintered samples of β-TUPD solid solutions were pre-irradiated with ion beams with various conditions (fluence, stopping power) then submitted to leaching tests in different media (pH, temperature, complexing reagents, flow rate, ...). The normalized dissolution rates depend significantly on the amorphous fraction (increase by a factor of 10–100 between unirradiated and fully amorphized materials). On the contrary, the pre-irradiation of the samples does not affect the kinetic parameters of the dissolution such as the partial order relative to the proton concentration (n = 0.37 ± 0.01 and n = 0.34 ± 0.01 for unirradiated and fully amorphized samples, respectively) and the activation energy of the reaction of dissolution (Eapp = 49 ± 4 kJ mol−1 and Eapp = 42 ± 4 kJ mol−1 for unirradiated and partly amorphized samples (fA < 1), respectively)

    Methylene Diphenyl Diisocyanate

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    The report provides the comprehensive risk assessment of the substance Methylenediphenyl diisocyanate (MDI). It has been prepared by Belgium in the frame of Council Regulation (EEC) No. 793/93 on the evaluation and control of the risks of existing substances, following the principles for assessment of the risks to humans and the environment, laid down in Commission Regulation (EC) No. 1488/94. Part I - Environment This part of the evaluation considers the emissions and the resulting exposure to the environment in all life cycle steps. Following the exposure assessment, the environmental risk characterisation for each protection goal in the aquatic, terrestrial and atmospheric compartment has been determined. The environmental risk assessment concludes that there is no concern. Part II ¿ Human Health This part of the evaluation considers the emissions and the resulting exposure to human populations in all life cycle steps. The scenarios for occupational exposure, consumer exposure and humans exposed via the environment have been examined and the possible risks have been identified. The human health risk assessment concludes that there is concern for workers and consumers with regard to irritation of skin, eye and respiratory tract, skin sensitisation and lung effects induced by repeated inhalation exposure. There is a need for further information and for testing (on hold) on the toxicity for fertility for workers and consumers. For humans exposed via the environment and for human health (physico-chemical properties) there is no concern. The conclusions of this report will lead to risk reduction measures to be proposed by the Commission¿s committee on risk reduction strategies set up in support of Council Regulation (EEC) N. 793/93.JRC.DDG.I.2-Chemical assessment and testin

    A kilobit hidden SNFS discrete logarithm computation

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    We perform a special number field sieve discrete logarithm computation in a 1024-bit prime field. To our knowledge, this is the first kilobit-sized discrete logarithm computation ever reported for prime fields. This computation took a little over two months of calendar time on an academic cluster using the open-source CADO-NFS software. Our chosen prime pp looks random, and p1p--1 has a 160-bit prime factor, in line with recommended parameters for the Digital Signature Algorithm. However, our p has been trapdoored in such a way that the special number field sieve can be used to compute discrete logarithms in F_p\mathbb{F}\_p^* , yet detecting that p has this trapdoor seems out of reach. Twenty-five years ago, there was considerable controversy around the possibility of back-doored parameters for DSA. Our computations show that trapdoored primes are entirely feasible with current computing technology. We also describe special number field sieve discrete log computations carried out for multiple weak primes found in use in the wild. As can be expected from a trapdoor mechanism which we say is hard to detect, our research did not reveal any trapdoored prime in wide use. The only way for a user to defend against a hypothetical trapdoor of this kind is to require verifiably random primes

    Two-Center Integrals for r_{ij}^{n} Polynomial Correlated Wave Functions

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    All integrals needed to evaluate the correlated wave functions with polynomial terms of inter-electronic distance are included. For this form of the wave function, the integrals needed can be expressed as a product of integrals involving at most four electrons

    Protocolized Brain Oxygen Optimization in Subarachnoid Hemorrhage.

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    Brain tissue hypoxia (P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; &lt; 20 mmHg) is common after subarachnoid hemorrhage (SAH) and associated with poor outcome. Recent data suggest that brain oxygen optimization is feasible and reduces the time spent with P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; &lt; 20 mmHg from 45 to 16% in patients with severe traumatic brain injury. Here, we intended to quantify the brain tissue hypoxia burden despite implementation of a protocolized treatment approach in poor-grade SAH patients and to identify the simultaneous occurrence of pathologic values potentially amenable to treatment. We present a bi-centric observational cohort study including 100 poor-grade SAH patients admitted to two tertiary care centers who underwent multimodal brain monitoring and were managed with a P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; -targeted protocolized approach. P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; optimization (≥ 20 mmHg) included a stepwise neuro-intensive care approach, aiming to prevent low cerebral perfusion pressure (CPP), and blood hemoglobin, and to keep normocapnia, normoxemia, and normothermia. Based on routine blood gas analysis, hemoglobin, PaCO &lt;sub&gt;2,&lt;/sub&gt; and PaO &lt;sub&gt;2&lt;/sub&gt; data were matched to 2-h averaged data of continuous CPP, P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; , core temperature, and to hourly cerebral microdialysis (CMD) samples over the first 11 days. Patients had a Glasgow Coma Scale of 3 (IQR 3-4) and were 58 years old (IQR 48-66). Overall incidence of brain tissue hypoxia was 25%, which was not different between both sites despite differences in the treatment approach. During brain tissue hypoxia, episodes of CPP &lt; 70 mmHg (27%), PaCO &lt;sub&gt;2&lt;/sub&gt; &lt; 35 mmHg (19%), PaO &lt;sub&gt;2&lt;/sub&gt; &lt; 80 mmHg (14%), Hb &lt; 9 g/dL (11%), metabolic crisis (CMD-lactate/pyruvate ratio &gt; 40, and CMD-glucose &lt; 0.7 mmol/L; 7%), and temperature &gt; 38.3 °C (4%) were common. Our results demonstrate that brain tissue hypoxia remains common despite implementation of a P &lt;sub&gt;bt&lt;/sub&gt; O &lt;sub&gt;2&lt;/sub&gt; -targeted therapy in poor-grade SAH patients, suggesting room for further optimization
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