88 research outputs found

    Tracking the variable North Atlantic sink for atmospheric CO2

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    3 páginas, 1 tabla, 3 figuras.-- Watson, Andrew J. ... et al.The oceans are a major sink for atmospheric carbon dioxide (CO2). Historically, observations have been too sparse to allow accurate tracking of changes in rates of CO2 uptake over ocean basins, so little is known about how these vary. Here, we show observations indicating substantial variability in the CO2 uptake by the North Atlantic on time scales of a few years. Further, we use measurements from a coordinated network of instrumented commercial ships to define the annual flux into the North Atlantic, for the year 2005, to a precision of about 10%. This approach offers the prospect of accurately monitoring the changing ocean CO2 sink for those ocean basins that are well covered by shipping routes.Peer reviewe

    The tourism potential of border regions: endogenous resources and destination image evaluation

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    Tourism has an enormous potential while instrument of regional development. However, the opportunities are not the same for each territory and it is easy to understand that, considering the resources available, not every region has the choice to base its development strategy in the touristic industry. Taking this in consideration, the mission of classifying, evaluating and compare, from a consistent and realistic point of view, several groups of tourist resources became a necessary task and a precondition to define the touristic vocation of a region. This approach allows selecting the best alternative to tourism development. The paper attempts to catalogue and evaluate the tourist resources of Spanish Baixo Miño and Portuguese Alto Minho, as well as to analyze the complementary elements and the external factors related with the image of the destination. We believe that the before mention methodology might be a valuable instrument to identify the strengths and weaknesses of the selected territory in what refers to its touristic development.Fundação para a Ciência e a Tecnologia (FCT

    Tourism in rural areas: a comparative analysis of Galicia and North of Portugal

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    This paper unveils the results stemming from two parallel researches, whose scope of analysis was tourism in rural areas (TRA) structures, as established in both northeast regions of the Iberia Peninsula which shape the Euro-region Galicia-North of Portugal. Firstly, a descriptive analysis of the regulations and the TRA supply for both territories is presented, and an evaluation of the strategies which have been followed by the private entrepreneurs and the public administration of each of them, as far as the utilisation of resources is concerned, is done. The symmetries and asymmetries of the touristic structures of those regions are also underlined. In the second part of this study, the above mentioned strategies will be discussed at length seeking to pinpoint how they configure and shape very similar touristic models based upon the use of natural and historical resources, which somehow display common features. Finally, it is sought to materialise a brief conclusion

    GPS and GLONASS Static and Kinematic PPP results

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    Precise point positioning (PPP) involves observations from a single global navigation satellite system (GNSS) receiver and benefits of satellite orbit and clock products obtained from the global infrastructure of permanent stations. PPP avoids the expense and logistic difficulties of deploying a network of GNSS receivers around survey areas in isolated places, such as the arctic or less populated areas. Potential accuracies are at the centimeter level for static applications and at the subdecimeter level for kinematic applications. Static and kinematic PPP based on the processing of global positioning system (GPS) observations is limited by the number of visible satellites, which is often insufficient for urban or mountain applications, or it can be partially obstructed or present multipath effects. Even if a number of GPS satellites are available, the accuracy and reliability can still be affected by poor satellite geometry. One possible way of increasing satellite signal availability and positioning reliability is to integrate GPS and GLONASS observations. This case study deals with the possibilities of combining GPS and GLONASS dual-frequency measurements on the static and kinematic PPP solution to reduce the convergence time and improve the accuracy of the solution. The results show that the addition of the GLONASS constellation does not always improve the convergence of static PPP; the kinematic results (car and walk trajectories) present better accuracy from the GPS1GLONASS solution rather than the GPS-only solution. The MagicGNSS software was used in processing of all observationsThis research is supported by Spanish Science and Innovation Directorate Project No. AYA2010-18706. The authors greatly appreciate the efforts of the IGS, Analysis and Data Centers, and tracking station managers for generating high-quality data and products and for making them available to the GNSS community in a timely and reliable way. The authors would like to thank Alvaro Mozo and Ricardo Piriz from GMV Aerospace for the free use of the online software MagicGNSS and their valuable comments on how MagicGNSS works. The three anonymous reviewers are kindly acknowledged for their contribution to the improvement of the paper with their valuable comments and suggestions.Anquela Julián, AB.; Martín Furones, ÁE.; Berné Valero, JL.; Padin Devesa, J. (2013). GPS and GLONASS Static and Kinematic PPP results. Journal of Surveying Engineering. 139(1):47-58. https://doi.org/10.1061/(ASCE)SU.1943-5428.0000091S4758139

    Neo-Suprahepatic cava: A case report of a modified technique for domino liver transplantation

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    Domino liver transplantation, introduced in 1997, originally consisted of a graft from a patient with familial amyloidotic polyneuropathy used as a donor for a compatible recipient, thus increasing the pool of hepatic grafts for liver transplantation. The aim of this report was to present a modification on the technique for outflow reconstruction in domino liver transplantation first proposed by Liu et al and Cescon et al. In this description we proposed a new technique that differs from the one mentioned above by performing a neo-suprahepatic cava, constructed using only an iliac vein graft, facilitating the anastomosis as if it was a regular cadaveric liver transplant.Fil: Padín, J. M.. Fundación Favaloro; ArgentinaFil: Pfaffen, G.. Fundación Favaloro; ArgentinaFil: Pérez Fernández, I.. Fundación Favaloro; ArgentinaFil: Sandi, M.. Fundación Favaloro; ArgentinaFil: Ramisch, D.. Fundación Favaloro; ArgentinaFil: Barros Schelotto, P.. Fundación Favaloro; ArgentinaFil: Gondolesi, Gabriel Eduardo. Fundación Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Diseño automático de operadores morfológicos aplicado a la segmentación de angiografías retinales

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    El diseño automático de operadores morfológicos, mediante aprendizaje computacional, surge ante las múltiples dificultades que se tienen en el diseño heurístico, el cual requiere de cierta experiencia y conocimiento técnico del usuario. En el presente trabajo se aplican los Operadores Morfológicos de Ventana, o también llamados W-operadores, diseñados mediante aprendizaje computacional, para la eliminación del ruido en imágenes de angiografías retinales, previamente segmentadas utilizando Morfología Matemática Difusa. Los resultados obtenidos mostraron una reducción del nivel de ruido, lo cual mejora la calidad de la segmentación y facilita al especialista la interpretación de la información contenida en dichas imágenes.Sociedad Argentina de Informática e Investigación Operativ

    On Standard Reductions to Relative Gravity Measurements. A Case Study Through the Establishment of the New Local Gravity Net in the Province of Valencia (Spain)

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    This is an author's accepted manuscript of an article published in: “Survey Review"; Volume 43, Issue 319, 2011; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1179/003962610X12747001420825Standard reductions to gravity readings due to Earth tides, ocean loading and attraction, polar motion, instrumental height and air pressure variations and loading of atmospheric masses are studied in this paper from a practical point of view, that is, taking into account their numerical values and their influence on gravimetric readings and relative gravimetric observations. The study was carried out using the observations and definition of a new local gravimetric net. This new local gravimetric net has been established in the province of Valencia (Eastern Spain) to meet the increasing requirements of geophysics, geology, geodesy and geodynamics. The net comprises 21 sites, which are an average of 45 km apart and was measured using Lacoste & Romberg D203 and G301 gravimeters. Gravity values were determined using one fixed station in relation to an absolute one and 202 relative gravimetric observables. Reductions are applied for Earth tides (with real accurate amplitude and phase-difference for the principal tidal waves analysed from 301 digitally recorded days of gravity readings) where oceanic attraction and loading has been considered. In addition, reductions for polar motion, vertical gradient to instrument height and air pressure and loading of atmospheric masses have been applied. The net was established using least square adjustment where the weights of each relative gravimetric observable were determined by iterative estimation in accordance with the Huber robust estimation procedure. Obtained standard deviations of the final gravity values have an average value of 18x10-8 ms-2 (18 µGal), minimum value of 10x10-8 ms-2 and maximum value of 26x10-8 ms-2 . The statistical analysis of the results concludes with a precision and reliability determination. Discussion of the numerical values obtained in the standard gravimetric reductions shows the importance of each one in the final solution, bearing in mind that the relative gravimetric observables have been obtained using Lacoste & Romberg instruments and the geographical location of the net. The main conclusion is that only Earth tides reduction (with approximate amplitude and phase-difference numbers for the principal tidal waves) have to be taken into accountMartín Furones, ÁE.; Anquela Julián, AB.; Padin Devesa, J.; Berné Valero, JL. (2011). On Standard Reductions to Relative Gravity Measurements. A Case Study Through the Establishment of the New Local Gravity Net in the Province of Valencia (Spain). Survey Review. 43(319):16-29. doi:10.1179/003962610X12747001420825S162943319Boedecker, G., & Richter, B. (1981). The new gravity base net 1976 of the Federal Republic of Germany (DSGN 76). Bulletin Géodésique, 55(3), 250-266. doi:10.1007/bf02530865Cartwright, D. E., & Tayler, R. J. (2007). New Computations of the Tide-generating Potential. Geophysical Journal of the Royal Astronomical Society, 23(1), 45-73. doi:10.1111/j.1365-246x.1971.tb01803.xCharles, K. and Hipkin, R.G. 1994. British precise gravity net 1993. Joint symposium of the International Gravity Comission and the International Geoid Comission, Symposium 113: 39–45, Graz, Austria. Ed. Springer-Verlag.Farrell, W. E. (1972). Deformation of the Earth by surface loads. Reviews of Geophysics, 10(3), 761. doi:10.1029/rg010i003p00761Jentzsch, G. (s. f.). Earth tides and ocean tidal loading. Lecture Notes in Earth Sciences, 145-171. doi:10.1007/bfb0011461Torge, W. 1989. Gravimetry. Ed. Walter de Gruyter, Berlin-New York. 465 pages.Wahr, J. M. (1985). Deformation induced by polar motion. Journal of Geophysical Research, 90(B11), 9363. doi:10.1029/jb090ib11p09363Wenzel, G. 1998. Format and structure for the exchange of high precision tidal data, http://www.ife.uni-hannover.de/∼Wenzel/format/format.html, acceded on February 1999

    Carbon nanotubes gathered onto silica particles lose their biomimetic properties with the cytoskeleton becoming biocompatible

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    Carbon nanotubes (CNTs) are likely to transform the therapeutic and diagnostic fields in biomedicine during the coming years. However, the fragmented vision of their side effects and toxicity in humans has proscribed their use as nanomedicines. Most studies agree that biocompatibility depends on the state of aggregation/dispersion of CNTs under physiological conditions, but conclusions are confusing so far. This study designs an experimental setup to investigate the cytotoxic effect of individualized multiwalled CNTs compared to that of identical nanotubes assembled on submicrometric structures. Our results demonstrate how CNT cytotoxicity is directly dependent on the nanotube dispersion at a given dosage. When CNTs are gathered onto silica templates, they do not interfere with cell proliferation or survival becoming highly compatible. These results support the hypothesis that CNT cytotoxicity is due to the biomimetics of these nanomaterials with the intracellular nanofilaments. These findings provide major clues for the development of innocuous CNT-containing nanodevices and nanomedicines.Acknowledgments: This work was supported by the Spanish MINECO Project (references PI13/01074, PI16/00496 and CTM2014–58481-R, IDIVAL INNVAL15/15), Xunta de Galicia (Centro Singular de Investigación de Galicia-Accreditation 2016–2019 and EM2014/035), European Regional Development Fund – ERDF and Fundación Tatiana Pérez de Guzmán El Bueno

    Murine muscle engineered from dermal precursors: an in vitro model for skeletal muscle generation, degeneration and fatty infiltration.

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    Skeletal muscle can be engineered by converting dermal precursors into muscle progenitors and differentiated myocytes. However, the efficiency of muscle development remains relatively low and it is currently unclear if this is due to poor characterization of the myogenic precursors, the protocols used for cell differentiation, or a combination of both. In this study, we characterized myogenic precursors present in murine dermospheres, and evaluated mature myotubes grown in a novel three-dimensional culture system. After 57 days of differentiation, we observed isolated, twitching myotubes followed by spontaneous contractions of the entire tissue-engineered muscle construct on an extracellular matrix (ECM). In vitro engineered myofibers expressed canonical muscle markers and exhibited a skeletal (not cardiac) muscle ultrastructure, with numerous striations and the presence of aligned, enlarged mitochondria, intertwined with sarcoplasmic reticula (SR). Engineered myofibers exhibited Na+- and Ca2+-dependent inward currents upon acetylcholine (ACh) stimulation and tetrodotoxin-sensitive spontaneous action potentials. Moreover, ACh, nicotine, and caffeine elicited cytosolic Ca2+ transients; fiber contractions coupled to these Ca2+ transients suggest that Ca2+ entry is activating calcium-induced calcium release from the SR. Blockade by d-tubocurarine of ACh-elicited inward currents and Ca2+ transients suggests nicotinic receptor involvement. Interestingly, after 1 month, engineered muscle constructs showed progressive degradation of the myofibers concomitant with fatty infiltration, paralleling the natural course of muscular degeneration. We conclude that mature myofibers may be differentiated on the ECM from myogenic precursor cells present in murine dermospheres, in an in vitro system that mimics some characteristics found in aging and muscular degeneration

    Air-sea CO2 fluxes in the Atlantic as measured during the FICARAM cruises

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    A total of fourteen hydrographic cruises spanning from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean, under the framework of the Spanish research project FICARAM. The performed underway measurements are processed and analysed to describe the meridional air-sea CO2 fluxes (F CO2) along the Atlantic Ocean. The data was organised into different biogeochemical oceanographic provinces, according mainly to the thermohaline characteristics. The obtained spatial and temporal distributions of F CO2 follow the generally expected patterns and annual trends. The Subtropical regions in both hemispheres alternated the CO2 source and sink nature from autumn to spring, respectively. On the other hand, Tropical waters and the Patagonian Sea clearly behaved as sinks of atmospheric CO2 like the waters of the Drake Passage during autumn. The obtained results during the cruises also revealed significant long-term trends, such as the warming of equatorial waters (0.11±0.03 Cyr−1) and the decrease of surface salinity (−0.16±0.01 yr−1) in tropical waters caused by the influence of the Amazon River plume. This reduction in surface salinity appears to have a direct influence over the CO2 storage rates, fostering the uptake capacity of atmospheric CO2 (−0.09±0.03 molm−2 yr−1). An analysis of the biogeochemical forcing on the CO2 fugacity (fCO2) variability performed from an empirical algorithm highlighted the major role of the Amazon River input in the tropical North Atlantic fluxes. In addition, it has provided a quantitative measure of the importance of the thermodynamic control of F CO2 at temperate latitudes
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