3,236 research outputs found

    Flujos de agua y energía en los últimos cuarenta y dos años de agricultura en Argentina

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    Tesis optar por el grado de Doctor en Ciencias Agrarias, de la Universidad Nacional de Mar del Plata, en 2014Una manera relevante de describir procesos ecológicos es a través del análisis de los flujos de agua y energía. Estos dos recursos son, probablemente, los insumos de mayor importancia para la agricultura en Argentina. La eficiencia en el uso del agua y la energía, particularmente la energía fósil, en las actividades productivas del país será seguramente uno de los principales aspectos a considerar en el futuro cercano, sobre todo por sus implicancias respectivas en las Huellas de Agua y de Carbono. La finalidad de la presente Tesis fue identificar y evaluar desde una perspectiva sistémica la dinámica de los flujos de agua y energía en la gran región agrícola argentina, durante los últimos 42 años, período para el cual se contó con información adecuada. Se caracterizaron los modelos agrícolas y ganaderos representativos a partir de ambas variables, y se identificaron diferencias entre las distintas eco-regiones y entre períodos de tiempo. Se evaluaron además los impactos del avance de la frontera agrícola y se interpretaron los patrones espaciales y temporales de estos flujos, utilizando un marco de análisis multiescalar. El área cubierta por este estudio fue de alrededor de 1,5 millones de km2, representando el 63% de la superficie continental del país. Los flujos de agua y energía fueron caracterizados a partir de seis indicadores agro-ecológicos: consumo de energía fósil, producción de energía, eficiencia de uso de la energía fósil, consumo de agua, eficiencia en el uso del agua y relación agua consumida-energía producida. Se encontraron patrones espaciales y temporales heterogéneos, pero con una tendencia al aumento en el consumo, en la producción y en la eficiencia del uso de ambos recursos: agua y energía. En general, la región pampeana contribuyó más a estos flujos en términos absolutos, pero en ecoregiones del NOA y NEA se observaron los mayores cambios relativos. Los resultados se utilizaron para construir modelos interpretativos, que explican la incidencia de otras variables sobre los flujos mencionados, y cómo varían estas relaciones a distintas escalas espaciales y temporales. Los flujos de agua y energía se relacionaron de manera heterogénea con el uso de la tierra y los niveles de producción de los principales commodities, tanto en el tiempo como en el espacio. La fortaleza del trabajo radica en que permitió mejorar los conocimientos sobre las implicancias energéticas e hidrológicas de la expansión e intensificación agropecuaria de secanoargentina.A relevant way to describe ecological processes is through the analysis of water and energy fluxes. These two resources are probably the most important for agriculture in Argentina. Water and energy (especially fossil energy) efficiencies will be surely one of the main aspects to consider in the near future in the country’s productive activities, considering their respective influence on Water and Carbon Footprints. This Thesis aimed at identifying and evaluating, from a systemic perspective, the dynamics of water and energy fluxes in main agricultural area of Argentina, during the last 42 years, which was the period with adequate information. Agriculture and cattle productive systems were characterized using water and energy variables, and differences were found among regions, and among periods of time. The environmental impact of the expansion of the agricultural frontier was also evaluated, and the spatial and temporal patterns of these fluxes were analyzed in a multi-scale framework. The study area was of about 1.5 million of square km, representing 63% of the country’s continental area. Water and energy fluxes were characterized by using six agro-ecological indicators: use of fossil energy, energy production, fossil energy use efficiency, water use, wateruse efficiency and water use to energy production ratio. Spatial and temporal patterns were complex and showed a trend to higher energy use, production and efficiency, and higher water use and water-use efficiency. In general, the pampas’ region contributed the most to these fluxes in absolute terms; but north-western and north-eastern regions showed the most evident changes in relative terms. Results were used to construct interpretative models to explain the incidence of other variables on the fluxes mentioned above, and how these relationships vary over time and space. The fluxes were also related in a heterogeneous way to land use and intensification levels of the main commodities, both in time and space. The strength of this study was it improved the knowledge about the hydrological and energetic issues of rain-fed agricultural expansion and intensification in Argentina.Estación Experimental Agropecuaria AnguilFil: Frank, Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentin

    Effectiveness of Direct Laser Interference Patterning and Peptide Immobilization on Endothelial Cell Migration for Cardio-Vascular Applications: An In Vitro Study

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    Endothelial coverage of an exposed cardiovascular stent surface leads to the occurrence of restenosis and late-stent thrombosis several months after implantation. To overcome this difficulty, modification of stent surfaces with topographical or biochemical features may be performed to increase endothelial cells’ (ECs) adhesion and/or migration. This work combines both strategies on cobalt-chromium (CoCr) alloy and studies the potential synergistic effect of linear patterned surfaces that are obtained by direct laser interference patterning (DLIP), coupled with the use of Arg-Gly-Asp (RGD) and Tyr-Ile-Gly-Ser-Arg (YIGSR) peptides. An extensive characterization of the modified surfaces was performed by using AFM, XPS, surface charge, electrochemical analysis and fluorescent methods. The biological response was studied in terms of EC adhesion, migration and proliferation assays. CoCr surfaces were successfully patterned with a periodicity of 10 µm and two different depths, D (≈79 and 762 nm). RGD and YIGSR were immobilized on the surfaces by CPTES silanization. Early EC adhesion was increased on the peptide-functionalized surfaces, especially for YIGSR compared to RGD. High-depth patterns generated 80% of ECs’ alignment within the topographical lines and enhanced EC migration. It is noteworthy that the combined use of the two strategies synergistically accelerated the ECs’ migration and proliferation, proving the potential of this strategy to enhance stent endothelialization

    Effectiveness of Direct Laser Interference Patterning and Peptide Immobilization on Endothelial Cell Migration for Cardio-Vascular Applications: An In Vitro Study

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    Endothelial coverage of an exposed cardiovascular stent surface leads to the occurrence of restenosis and late-stent thrombosis several months after implantation. To overcome this difficulty, modification of stent surfaces with topographical or biochemical features may be performed to increase endothelial cells’ (ECs) adhesion and/or migration. This work combines both strategies on cobalt-chromium (CoCr) alloy and studies the potential synergistic effect of linear patterned surfaces that are obtained by direct laser interference patterning (DLIP), coupled with the use of Arg-Gly-Asp (RGD) and Tyr-Ile-Gly-Ser-Arg (YIGSR) peptides. An extensive characterization of the modified surfaces was performed by using AFM, XPS, surface charge, electrochemical analysis and fluorescent methods. The biological response was studied in terms of EC adhesion, migration and proliferation assays. CoCr surfaces were successfully patterned with a periodicity of 10 µm and two different depths, D (≈79 and 762 nm). RGD and YIGSR were immobilized on the surfaces by CPTES silanization. Early EC adhesion was increased on the peptide-functionalized surfaces, especially for YIGSR compared to RGD. High-depth patterns generated 80% of ECs’ alignment within the topographical lines and enhanced EC migration. It is noteworthy that the combined use of the two strategies synergistically accelerated the ECs’ migration and proliferation, proving the potential of this strategy to enhance stent endothelialization

    Plasma and stool metabolomic biomarkers of non-alcoholic fatty liver disease in Argentina

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    Background: Non-invasive biomarkers are urgently needed to identify patients with non-alcoholic fatty liver disease (NAFLD) at risk of disease progression, particularly in high prevalence areas such as Latin America. In this regard, targeted metabolomics is a powerful technology for discovering new gut microbiome-derived metabolites. Thus, we aimed to identify potential metabolomic biomarkers related to NAFLD stage in Argentina, and to assess their relationship with clinical and host genetic factors. Methods: Adult healthy volunteers (HV) and biopsy-proven simple steatosis (SS) or non-alcoholic steatohepatitis (NASH) patients were recruited. Demographic, clinical and food frequency consumption data, as well as plasma and stool samples were collected. SNP rs738409 (PNPLA3 gene) was determined in all volunteers. HPLC and flow injection analysis with MS/MS in tandem was applied for metabolomic studies using the MxP Quant 500 Kit (Biocrates Life Sciences AG, Austria). Significantly different metabolites among groups were identified with MetaboAnalyst v4.0. Bivariate and multivariate analyses were used to identify variables that were independently related to NAFLD stage. Forward stepwise logistic regression models were constructed to design the best feature combination that could distinguish between study groups. Receiver Operating Characteristic (ROC) curves were used to evaluate models? accuracy.Results: 19 HV, 12 SS and 22 NASH patients were recruited. Diet was similar between groups. The concentration of 33 out of 424 detected metabolites (25 in plasma and 8 in stool) was significantly different among study groups. Levels of triglycerides (TG) were higher among NAFLD patients, whereas levels of phosphatidylcholines (PC) and lysoPC were higher among HV. The PNPLA3 risk genotype for NAFLD and NASH (GG) was related to higher plasma levels of eicosenoic acid FA(20:1) (p<0.001). Plasma metabolites showed a higher accuracy for diagnosis of NAFLD and NASH when compared to stool metabolites (Table 1). Body mass index (BMI) and plasma levels of PC aa C24:0, FA(20:1) and TG(16:1_34:1) showed high accuracy for diagnosis of NAFLD; whereas the best AUROC for discriminating NASH from SS was that of plasma levels of PC aa C24:0 and PC ae C40:1 (Table 1).Conclusions: Gut microbiome-derived metabolomic biomarkers were identified in plasma and stool, but plasma metabolites were better diagnostic biomarkers of NAFLD and NASH in Argentina. Further validation studies are needed.Fil: Mazzini, Flavia Noelia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Hospital Italiano. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional E Ingenieria Biomedica.; ArgentinaFil: Cook, Frank. Novartis Institutes For Biomedical Research; Estados UnidosFil: Gounarides, John. Novartis Institutes For Biomedical Research; Estados UnidosFil: Marciano, Sebastian. Hospital Italiano; ArgentinaFil: Haddad, Leila. Hospital Italiano; ArgentinaFil: Tamaroff, Ana Jesica. Hospital Italiano; ArgentinaFil: Casciato, Paola. Hospital Italiano; ArgentinaFil: Narvaez, Adriana Haydée. Hospital Italiano; ArgentinaFil: Mascardi, María Florencia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Hospital Italiano. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional E Ingenieria Biomedica.; ArgentinaFil: Anders, Margarita. Hospital Alemán; ArgentinaFil: Orozco, Federico. Hospital Alemán; ArgentinaFil: Quiroz, Nicolas. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Hospital Italiano. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional E Ingenieria Biomedica.; ArgentinaFil: Risk, Marcelo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Hospital Italiano. Instituto de Medicina Traslacional E Ingenieria Biomedica. - Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional E Ingenieria Biomedica.; ArgentinaFil: Gutt, Susana. Hospital Italiano; ArgentinaFil: Gadano, Adrián Carlos. Hospital Italiano; ArgentinaFil: Mendez Garcia, Celia. Hospital Italiano; ArgentinaFil: Marro, Martin. Novartis Institutes For Biomedical Research; Estados UnidosFil: Penas Steinhardt, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Trinks, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional e Ingeniería Biomédica - Hospital Italiano. Instituto de Medicina Traslacional e Ingeniería Biomédica.- Instituto Universitario Hospital Italiano de Buenos Aires. Instituto de Medicina Traslacional e Ingeniería Biomédica; ArgentinaThe Liver Meeting Digital ExperienceEstados UnidosAmerican Association for the Study of the Liver Diseas

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Roadmap on spatiotemporal light fields

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    Spatiotemporal sculpturing of light pulse with ultimately sophisticated structures represents the holy grail of the human everlasting pursue of ultrafast information transmission and processing as well as ultra-intense energy concentration and extraction. It also holds the key to unlock new extraordinary fundamental physical effects. Traditionally, spatiotemporal light pulses are always treated as spatiotemporally separable wave packet as solution of the Maxwell's equations. In the past decade, however, more generalized forms of spatiotemporally nonseparable solution started to emerge with growing importance for their striking physical effects. This roadmap intends to highlight the recent advances in the creation and control of increasingly complex spatiotemporally sculptured pulses, from spatiotemporally separable to complex nonseparable states, with diverse geometric and topological structures, presenting a bird's eye viewpoint on the zoology of spatiotemporal light fields and the outlook of future trends and open challenges.Comment: This is the version of the article before peer review or editing, as submitted by an author to Journal of Optics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i
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