368 research outputs found

    ¿HAY INCONMENSURABILIDAD TECNOLÓGICA?

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    Mediante la noción matemática de inconmensurabilidad, Kuhn indicó la falta de un lenguaje común que hiciese posible la traducción de los términos que se emplean de ordinario en las teorías científicas. Sin embargo, Kuhn no extendió el alcance de la relación de inconmensurabilidad al dominio de la tecnología, aunque recurrió a él para ilustrar este fenómeno semántico. Pese a lo controversial que pueda resultar, en este trabajo mostraré que la historia de la tecnología proporciona la evidencia necesaria a favor de la tesis de que hay inconmensurabilidad tecnológica. Para ello, examinaré dicha tesis y explicaré cómo operaría en el dominio de la tecnología. También analizaré dos casos históricos a su favor. El primero proviene de la sustitución de la teoría del contacto de la pila voltaica por la teoría química de la batería. El segundo caso se da a partir deltránsito de la teoría material del calor a la termodinámica. &nbsp

    Review of dynamic line rating systems for wind power integration

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    When a wind power system is connected to a network point there is a limit of power generation based on the characteristics of the network and the loads connected to it. Traditionally, transmission line limits are estimated conservatively assuming unfavourable weather conditions (high ambient temperature, full sun and low wind speed). However, the transmission capacity of an overhead line increases when wind speed is high, due to the cooling caused by wind in the distribution lines. Dynamic line rating (DLR) systems allow monitoring real weather conditions and calculating the real capacity of lines. Thus, when planning wind power integration, if dynamic line limits are considered instead of the conservative and static limits, estimated capacity increases. This article reviews all technologies developed for real-time monitoring during the last thirty years, as well as some case studies around the world, and brings out the benefits and technical limitations of employing dynamic line rating on overhead lines. Further, the use of these DLR systems in wind integration is reviewed.This work is financially supported by the Ministerio de Economía y Competitividad under the project DPI2013-44502-R and the Eusko Jaurlaritza under the project SAI12/103

    Improved parental dietary quality is associated with children’s dietary intake through the home environment

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    Background Improving access to supermarkets has been shown to improve some dietary outcomes, yet there is little evidence for such effects on children. Relatedly, there is a dearth of research assessing the impact of a structural change (i.e. supermarket in a former food desert) on the home environment and its relationship with children’s diet. Objective Assess the relative impact of the home environment on children’s diet after the introduction of a new supermarket in a food desert. Methods Among a randomly selected cohort of households living in a food desert, parental diet was assessed before and after the opening of a full-service supermarket. The home environment and children’s intake of fruits and vegetables was measured at one point – after the store’s opening. Structural equation models were used to estimate the pathways between changes in parental dietary quality at follow-up and children’s dietary intake through the home environment. ResultsParental dietary improvement after the supermarket opened was associated with having a better home environment (β = 0.45, p = 0.001) and with healthier children’s dietary intake (β = 0.46, p Conclusions Policy solutions designed to improve diet among low-resource communities should take into account the importance of the home environment

    Establishing a governance threshold in small-scale fisheries to achieve sustainability

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    The lack of effective governance is a major concern in small-scale fisheries. The implementation of governance that encompasses the three pillars of sustainability (social, economic, and ecological) is still a worldwide challenge. We examined nine stalked barnacle fisheries (Pollicipes pollicipes) across Southwest Europe to better understand the relationship between governance elements and sustainability. Our results show that nested spatial scales of management, the access structure, co- management, and fisher’s participation in monitoring and surveillance promote sustainability. However, it is not the mere presence of these elements but their level of implementation that drives sustainability. Efforts should be placed in the accomplishment of a minimum combination of local scales of management, access rights through individual quotas, instructive-consultative co- management and functional participation. Surpassing this threshold in future governance structures will start to adequately promote social, economic and ecologically sustainability in small-scale fisheries

    Fucoidan from Fucus Vesiculosus: Evaluation of the impact of the Sulphate content on Nanoparticle production and Cell toxicity

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    The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200–300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT−116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675–100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications.info:eu-repo/semantics/publishedVersio

    The Use Of Reverse Transcription-pcr For The Diagnosis Of X-linked Chronic Granulomatous Disease.

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    Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by a defective oxidative burst of phagocytes and subsequent impairment of their microbicidal activity. Mutations in one of the NADPH-oxidase components affect gene expression or function of this system, leading to the phenotype of CGD. Defects in gp91-phox lead to X-linked CGD, responsible for approximately 70% of CGD cases. Investigation of the highly heterogeneous genotype of CGD patients includes mutation analysis, Northern blot or Western blot assays according to the particular case. The aim of the present study was to use reverse transcription (RT)-PCR for the analysis of molecular defects responsible for X-linked CGD in eight Brazilian patients and to assess its potential for broader application to molecular screening in CGD. Total RNA was prepared from Epstein B virus-transformed B-lymphocytes and reverse transcribed using random hexamers. The resulting cDNA was PCR-amplified by specific and overlapping pairs of primers designed to amplify three regions of the gp91-phox gene: exons 1-5, 3-9, and 7-13. This strategy detected defective gp91-phox expression in seven patients. The RT-PCR results matched clinical history, biochemical data (nitroblue tetrazolium or superoxide release assay) and available mutation analysis in four cases. In three additional cases, RT-PCR results matched clinical history and biochemical data. In another case, RT-PCR was normal despite a clinical history compatible with CGD and defective respiratory burst. We conclude that this new application of RT-PCR analysis--a simple, economical and rapid method--was appropriate for screening molecular defects in 7 of 8 X-linked CGD patients.37625-3

    Granulomas en el prepucio de un equino causados por Micronema.

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    Se describe por primera vez en Colombia, un caso, no fatal, de parasitismo por Micronema sp, en un equino macho, causando una postitis granulamatosa. Se observaron numerosas larvas y nemátodos adultos, igualmente huevos hembrionados en cortes de tejidos coloreados con hematoxilina y eosina. Preparaciones de macerado de tejido granulomatoso, hicieron posible la observación detalladas del parásito para su identificación.Equinos-Caballo - caballo

    Primer registro del género Spicaticribra Johansen, Kociolek y Lowe en un embalse colombiano y revisión de los taxones infragenéricos presentes en América del Sur

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    The genus Spicaticribra Johansen, Kociolek, and Lowe is reported for the first time in Colombia, in surface sediment samples collected at Embalse La Fe. Materials were examined with light and scanning electron microscopies and their main morphologic and morphometric characters were compared to those of the remaining species of the genus. Based on these results we assigned them to Spicaticribra kingstonii and propose S. kodaikanaliana Kartrick and Kocioleck as a synonym. We conclude that the genus is represented in South America by only two species, S. patagonica Maidana restricted to the south region of the continent and S. kingstonii distributed across a broad latitudinal range.El género Spicaticribra Johansen, Kociolek y Lowe fue hallado por primera vez en Colombia, en muestras de sedimento superficial, recolectadas en el Embalse La Fe. En este trabajo el material recolectado se estudió bajo microscopios óptico y electrónico de barrido y se compararon los principales caracteres morfológicos y morfométricos con los de las otras especies del género. A partir de estos resultados fue posible establecer que los mismos corresponden a Spicaticribra kingstonii y se propone como sinónimo de esta especie a S. kodaikanaliana Kartrick y Kocioleck. Concluimos que en América del Sur, el género está representado por sólo dos especies, S. patagonica Maidana restringida al sur de continente y S. kingstonii distribuida en un amplio rango latitudinal.Facultad de Ciencias Naturales y Muse

    Chaotic Genetic Patchiness in the Highly Valued Atlantic Stalked Barnacle Pollicipes pollicipes from the Iberian Peninsula: Implications for Fisheries Management. Frontiers in Marine Science

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    The stalked barnacle Pollicipes pollicipes inhabits rocky shores from the Atlantic coasts of Brittany (France) to Senegal. Because of the culinary traditions of southern Europe, stalked barnacles represent an important target species for local fisheries on the Iberian Peninsula. To manage this fishery sustainably, it is therefore important to assess the dynamics of local populations over the Iberian coast, and how they are interconnected at a wider scale using finely tuned genetic markers. In this work, a new enriched library of GT microsatellites for P. pollicipes was prepared and sequenced using Ion TorrentTM Next Gen-Sequencing Technology. 1,423 adults and juveniles were sampled in 15 localities of three geographic regions: southern Portugal, Galicia and Asturias (both in northern Spain). Twenty polymorphic loci arranged in five multiplex PCRs were then tested and validated as new molecular tools to address the spatial and temporal genetic patterns of P. pollicipes. Our results revealed high genetic diversity among adults. However, juveniles were genetically more structured than their adult counterparts, which alternatively displayed much more connectivity among the three studied regions. The lack of spatial genetic heterogeneity in adults may be due to the overlapping of several generations of settlers coming from different geographic origins, which mainly depends on the orientation of residual currents along the coast during reproduction. The genetic differentiation of juveniles may indeed be congruent with Iberian Peninsula hydrodynamics, which can produce chaotic genetic patchiness (CGP) at small temporal scales due to sweepstake reproductive success, collective dispersal and/or self-recruitment. Remarkably, most of the genetic heterogeneity of juveniles found in this work was located in Galicia, which could represent an admixture between distinct metapopulations or an old refuge for the most northern populations. To conclude, high genetic variation in P. pollicipes can lead to the false impression of population panmixia at the Iberian scale by masking more restricted and current-driven larval exchanges between regions. This possibility should be taken into consideration for further specific management and conservation plans for the species over the Iberian Peninsula

    Lattice Distortions Around a Tl+ Impurity in NaI:Tl+ and CsI:Tl+ Scintillators. An Ab Initio Study Involving Large Active Clusters

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    Ab initio Perturbed Ion cluster-in-the-lattice calculations of the impurity centers NaI:Tl+ and CsI:Tl+ are pressented. We study several active clusters of increasing complexity and show that the lattice relaxation around the Tl+ impurity implies the concerted movement of several shells of neighbors. The results also reveal the importance of considering a set of ions that can respond to the geometrical displacements of the inner shells by adapting selfconsistently their wave functions. Comparison with other calculations involving comparatively small active clusters serves to assert the significance of our conclusions. Contact with experiment is made by calculating absorption energies. These are in excellent agreement with the experimental data for the most realistic active clusters considered.Comment: 7 pages plus 6 postscript figures, LaTeX. Submmited to Phys, Rev.
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