784 research outputs found
Prospección gravimétrica en el sistema transversal catalán
A Bouguer gravity anomaly may of the Transversal Subpirinean System is presented and interpreted. The most prominent feanire of the map is the strong regional effect produced by the Earth's crust thickening. The polinomial surface fit technique is used to substract this regional trend. The qualitative interpretation o£ the residual anomaly map obtained reflects a structure with block faulted basement
Estudis i recerca sobre edició i hàbits lectors.
Tot i la greu crisi econòmica que afecta globalment l'economia i la societat catalana i, en particular, al sector editorial i les polítiques d'incentivació en aquesta àrea, les iniciatives, en molts casos, sorgides de l'àmbit acadèmic han permès mantenir viu el coneixement sobre l'edició i els hàbits lectors de la població catalana. En aquest sentit, durant els anys 2010 i 2011 és destacable el nombre d'estudis publicats, els grups de recerca que s'han constituït o la quantitat de seminaris i congressos que s'han organitzat entorn de l'edició i els hàbits lectors a Catalunya. En l'àmbit de l'Administració pública cal destacar l'aprovació, a final de 2011, del Pla nacional de lectura 2012-2016 amb l'objectiu de vertebrar els esforços dels diferents sectors i àmbits de la societat catalana orientant-los cap a l'augment dels hàbits lectors dels ciutadans i així incrementar l'accés al coneixement i el capital cultural i humà del país. Entre els objectius més concrets que es planteja el Pla destaca l'increment del percentatge de població lectora per apropar-lo a la mitjana europea, passant des de l'actual 62 % al 71 %
Prospección gravimétrica en el sistema transversal catalán
En el presente trabajo se plantea la elaboración e interpretación del mapa de anomalías de Bouguer del Sistema Transversal Catalán. La característica más destacada del mapa es el marcado dominio de la tendencia regional, producida por el aumento de grosor de la corteza terrestre hacia el NW.
La sustracción de este efecto regional se ha realizado utilizando el método de ajuste a superficies polinómicas por mínimos cuadrados. La interpretación cuantitativa del mapa de anomalías residuales obtenido refleja la estructura en bloques del basamento.A Bouguer gravity anomaly may of the Transversal Subpirinean System is presented and interpreted. The most prominent feanire of the map is the strong regional effect produced by the Earth's crust thickening.
The polinomial surface fit technique is used to substract this regional trend. The qualitative interpretation o£ the residual anomaly map obtained reflects a structure with block faulted basement
Testing the convergence hypothesis for OECD countries: A reappraisal
This paper reviews the results of a number of empirical studies of convergence among the OECD countries and discusses some limitations of these studies. Moreover, the paper tries to deal with these limitations by presenting a new and more appropriate methodology: quantile regressions. The results obtained with this specification support the view that, even among the OECD countries, there are different clusters. The parameter representing the convergence hypothesis, despite being negative in every case, is higher in value and more significant as we advance to higher quantiles. These outcomes reveal a faster convergence between the countries that belong to the upper quantiles. Moreover, 1960-1970 is highlighted as the period in which convergence was more intense
Multi-Annual Evaluation of Time Series of Sentinel-1 Interferometric Coherence as a Tool for Crop Monitoring
Interferometric coherence from SAR data is a tool used in a variety of Earth observation applications. In the context of crop monitoring, vegetation indices are commonly used to describe crop dynamics. The most frequently used vegetation indices based on radar data are constructed using the backscattered intensity at different polarimetric channels. As coherence is sensitive to the changes in the scene caused by vegetation and its evolution, it may potentially be used as an alternative tool in this context. The objective of this work is to evaluate the potential of using Sentinel-1 interferometric coherence for this purpose. The study area is an agricultural region in Sevilla, Spain, mainly covered by 18 different crops. Time series of different backscatter-based radar vegetation indices and the coherence amplitude for both VV and VH channels from Sentinel-1 were compared to the NDVI derived from Sentinel-2 imagery for a 5-year period, from 2017 to 2021. The correlations between the series were studied both during and outside the growing season of the crops. Additionally, the use of the ratio of the two coherences measured at both polarimetric channels was explored. The results show that the coherence is generally well correlated with the NDVI across all seasons. The ratio between coherences at each channel is a potential alternative to the separate channels when the analysis is not restricted to the growing season of the crop, as its year-long temporal evolution more closely resembles that of the NDVI. Coherence and backscatter can be used as complementary sources of information, as backscatter-based indices describe the evolution of certain crops better than coherence.This research work was supported by the the European Space Agency under Project SEOM-S14SCI-Land (SInCohMap), and by the Spanish Ministry of Science and Innovation (State Agency of Research, AEI) and the European Funds for Regional Development (Project PID2020-117303GB-C22)
Research on women in science and higher education: a bibliometric analysis
The main objective of this paper is to study the development and growth of scientific literature on women in science and higher education. A total of 1415 articles and reviews published between 1991 and 2012 were extracted from the Thomson Reuters Web of Science database. Standard bibliometric indicators and laws (e.g. Price's, Lotka's, and Bradford's laws) were applied to these data. In addition, the Gender Inequality Index (GII) was obtained for each country in order to rank them. The results suggest an upward trend not only in the number of papers but also in the number of authors per paper. However, this increase in the number of authors was not accompanied by greater international collaboration. The interest in gender differences in science extends too many authors (n = 3064), countries (n = 67), and research areas (n = 86). Data showed a high dispersion of the literature and a small set of core journals focused on the topic. Regarding the research areas, the area with the highest frequency of papers was Education and Educational Research. Finally, our results showed that countries with higher levels of inequality (higher GII values) tend to present higher relative values of scientific productivity in the field
Sentinel-1 interferometric coherence as a vegetation index for agriculture
In this study, the use of Sentinel-1 interferometric coherence data as a tool for crop monitoring has been explored. For this purpose, time series of images acquired by Sentinel-1 and 2 spanning 2017 have been analysed. The study site is an agricultural area in Sevilla, Spain, where 16 different crop species were cultivated during that year. The time series of 6-day repeat-pass coherence measured at each polarimetric channel (VV and VH), as well as their difference, have been compared to the NDVI and to the backscattering ratio (VH/VV) and other indices based on backscatter. The contribution of different decorrelation sources and the effect of the bias from the space-averaged sample coherence magnitude estimation have been evaluated. Likewise, the usage of 12 days as temporal baseline was tested. The study has been carried for three different orbits, characterised by different incidence angles and acquisition times. All results support using coherence as a measure for monitoring the crop growing season, as it shows good correlations with the NDVI (R2>0.7), and its temporal evolution fits well the main phenological stages of the crops. Although each crop shows its own evolution, the performance of coherence as a vegetation index is high for most of them. VV is generally more correlated with the NDVI than VH. For crop types characterised by low plant density, this difference decreases, with VH even showing higher correlation values in some cases. For a few crop types, such as rice, the backscattering ratio outperforms the coherence in following the growth stages of the plants. Since both coherence and backscattering are directly computed from the radar images, they could be used as complementary sources of information for this purpose. Notably, the measured coherence performs well without the need of compensating the thermal noise decorrelation or the bias due to the finite equivalent number of looks.This work was supported in part by the European Space Agency under Project SEOM-S14SCI-Land (SInCohMap), and in part by the Spanish Ministry of Science and Innovation (State Agency of Research, AEI) and the European Funds for Regional Development under Project PID2020-117303GB-C22
Microvesicles and exosomes: new players in metabolic and cardiovascular disease
The past decade has witnessed an exponential increase in the number of publications referring to extracellular vesicles (EVs). For many years considered to be extracellular debris, EVs are now seen as novel mediators of endocrine signalling via cell-to-cell communication. With the capability of transferring proteins and nucleic acids from one cell to another, they have become an attractive focus of research for different pathological settings and are now regarded as both mediators and biomarkers of disease including cardio-metabolic disease. They also offer therapeutic potential as signalling agents capable of targeting tissues or cells with specific peptides or miRNAs. In this review, we focus on the role that microvesicles (MVs) and exosomes, the two most studied classes of EV, have in diabetes, cardiovascular disease, endothelial dysfunction, coagulopathies, and polycystic ovary syndrome. We also provide an overview of current developments in MV/exosome isolation techniques from plasma and other fluids, comparing different available commercial and non-commercial methods. We describe different techniques for their optical/biochemical characterization and quantitation. We also review the signalling pathways that exosomes and MVs activate in target cells and provide some insight into their use as biomarkers or potential therapeutic agents. In summary, we give an updated focus on the role that these exciting novel nanoparticles offer for the endocrine community
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