5,382 research outputs found
Reinterpretar la cultura española: el Centro de Estudios Históricos
El Centro de Estudios Históricos fue fundado por la Junta para Ampliación de Estudios en 1910. El objetivo era crear un sistema científico moderno, pero además los investigadores del Centro aspiraban a reinterpretar la cultura española, esto es, poner las nuevas bases sobre las que erigir un cuerpo doctrinal que diese carta de naturaleza a una nueva forma de aprehender la historia y la cultura española y contribuyese a la creación de un nuevo nacionalismo
Política cultural exterior alemana en España durante la República de Weimar
El enorme desarrollo que la ciencia alemana vivió durante el ultimo tercio del siglo XIX y primeras décadas del siglo XX encuentra en la eficiencia de su aparato organizativo una de sus principales causas. El sistema Althoff y la Notgemeinschaft der Deutschen Wissenschaft fueron los resultados más brillantes de una política científica orientada a colocar a Alemania al frente del desarrollo cientifíco europeo.The emergence of a scientific policy in Germany at the end of the 19th century and at the beginning of the 20th century is due to the fact that efficiency of the German scientific burocracy system. The Althoff’s System and the Notgemeinschaft der Deutschen Wissenschaft were the most significant outcomes of one policy which strove for placing Germany on the top of the European scientific development
Genetic Evidence for p75NTR-Dependent Tetraploidy in Cortical Projection Neurons from Adult Mice
A subpopulation of chick retinal projection neurons becomes tetraploid during development, an event prevented by blocking antibodies against p75 neurotrophin receptor (p75(NTR)). We have used an optimized flow cytometric assay, based on the analysis of unfixed brain cell nuclei, to study whether p75(NTR)-dependent neuronal tetraploidization takes place in the cerebral cortex, giving rise to projection neurons as well. We show that 3% of neurons in both murine neocortex and chick telencephalic derivatives are tetraploid, and that in the mouse ~85% of these neurons express the immediate early genes Erg-1 and c-Fos, indicating that they are functionally active. Tetraploid cortical neurons (65-80%) express CTIP2, a transcription factor specific for subcortical projection neurons in the mouse neocortex. During the period in which these neurons are born, p75(NTR) is detected in differentiating neurons undergoing DNA replication. Accordingly, p75(NTR)-deficient mice contain a reduced proportion of both NeuN and CTIP2-positive neocortical tetraploid neurons, thus providing genetic evidence for the participation of p75(NTR) in the induction of neuronal tetraploidy in the mouse neocortex. In the striatum tetraploidy is mainly associated with long-range projection neurons as well since ~80% of tetraploid neurons in this structure express calbindin, a marker of neostriatal-matrix spiny neurons, known to establish long-range projections to the substantia nigra and globus pallidus. In contrast, only 20% of tetraploid cortical neurons express calbindin, which is mainly expressed in layers II-III, where CTIP2 is absent. We conclude that tetraploidy mainly affects long-range projection neurons, being facilitated by p75(NTR) in the neocortex.Peer Reviewe
Effect of agro-climatic conditions on near infrared spectra of extra virgin olive oils
Authentication of extra virgin olive oil requires fast and cost-effective analytical procedures, such as near infrared spectroscopy. Multivariate analysis and chemometrics have been successfully applied in several papers to gather qualitative and quantitative information of extra virgin olive oils from near infrared spectra. Moreover, there are many examples in the literature analysing the effect of agro-climatic conditions on food content, in general, and in olive oil components, in particular. But the majority of these studies considered a factor, a non-numerical variable, containing this meteorological information. The present work uses all the agro-climatic data with the aim of highlighting the linear relationships between them and the near infrared spectra. The study begins with a graphical motivation, continues with a bivariate analysis and, finally, applies redundancy analysis to extend and confirm the previous conclusions.Peer Reviewe
An Analysis of Global Research Trends on Greenhouse Technology: Towards a Sustainable Agriculture
Greenhouse farming is an agricultural management system that has demonstrated its efficiency in intensifying food production. These systems constitute a feasible alternative for ensuring food supply, which is one of the greatest challenges faced by humankind in the twenty-first century. Technology has been able to meet the challenges related to greenhouse farming in both contributing to overcoming its limitations, correcting adverse impacts and ensuring system sustainability. The objective of this article is to analyse the global research trends in greenhouse technology over the last two decades, in order to identify the main driving agents, the most outstanding research lines and possible gaps in the literature. Different methodologies have been used for the analysis; both quantitative and qualitative. The principal results show that there are different relevant lines of research related to different aspects of greenhouse farming: the use of water for irrigation, the design of the optimum structure of the greenhouse, conserving the soil in the best growing conditions, energy consumption of the system as a whole, climate control within the facility and pest control. The research is characterized by the being composed largely of ad hoc studies, which hinders the international collaboration between researchers and institutions. The research approach has shifted from being focused on increasing production and cost savings to aspects related to resource conservation and sustainability
Preparation and Characterization of New Liposomes. Bactericidal Activity of Cefepime Encapsulated into Cationic Liposomes
Cefepime is an antibiotic with a broad spectrum of antimicrobial activity. However, this antibiotic has several side effects and a high degradation rate. For this reason, the preparation and characterization of new liposomes that are able to encapsulate this antibiotic seem to be an important research line in the pharmaceutical industry. Anionic and cationic liposomes were prepared and characterized. All cationic structures contained the same cationic surfactant, N,N,N-triethyl-N-(12-naphthoxydodecyl)ammonium. Results showed a better encapsulation-efficiency percentage (EE%) of cefepime in liposomes with phosphatidylcholine and cholesterol than with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). The presence of cholesterol and the quantity of egg-yolk phospholipid in the liposome increased the encapsulation percentage. The bactericidal activity against Escherichia coli of cefepime loaded into liposomes with phosphatidylcholine was measured. The inhibitory zone in an agar plate for free cefepime was similar to that obtained for loaded cefepime. The growth-rate constant of E. coli culture was also measured in working conditions. The liposome without any antibiotic exerted no influence in such a rate constant. All obtained results suggest that PC:CH:12NBr liposomes are biocompatible nanocarriers of cefepime that can be used in bacterial infections against Escherichia coli with high inhibitory activity
Los mercados alternativos bursátiles: Una perspectiva regulatoria
The debate over the appropriate regulation of financial markets has become a burning issue, especially as regards alternative stock markets aimed at small and medium-sized enterprises (SMEs). This article reviews the international research that, on the one hand, analyses alternative markets from an economic-regulatory perspective, and that, on the other hand, studies the control mechanisms that have been identified as key factors to overcoming the limitations of a light regulation, such as corporate governance, nominated advisors, and auditors. The results show that tougher legislation is not a panacea for solving the problems and the limitations that are presented by the development of these alternative stock markets, and that satisfactory results can be provided through the balance and permanent adjustment of the agents involved, and of control mechanisms.El debate sobre la adecuada regulación de los mercados financieros, y en especial sobre los mercados alternativos bursátiles dirigidos a las pequeñas y medianas empresas (PYME), es un tema de candente actualidad. Este trabajo realiza una revisión de los trabajos de investigación internacionales que, por un lado, analizan los mercados alternativos desde una perspectiva económico-regulatoria y, por otro lado, analizan los mecanismos de control que se han identificado como claves para superar las limitaciones de una regulación light y que ayudan al correcto funcionamiento de estos mercados. Entre ellos destacan el gobierno de la empresa, los asesores registrados y los auditores. Los resultados muestran que una legislación más dura no es la panacea para solucionar los problemas y limitaciones que está presentando el desarrollo de estos mercados alternativos bursátiles y sugieren que el equilibrio y permanente ajuste de los agentes participantes y los mecanismos de control proporcionan resultados satisfactorio
La regulación de los mercados alternativos bursálites: ¿clave del éxito?
El debate sobre la adecuada regulación de los mercados financieros, y en especial sobre los mercados alternativos
bursátiles dirigidos a las pequeñas y medianas empresas (PYME) es un tema de candente actualidad. Este trabajo
realiza una revisión de los trabajos de investigación internacionales que, por un lado, analizan los mercados alternativos
desde una perspectiva económico-regulatoria, y por otro lado, analizan los mecanismos de control que se han
identificado como claves para superar las limitaciones de una regulación light y que ayudan al correcto funcionamiento
de estos mercados. Entre ellos destacan el gobierno de la empresa, los asesores registrados y los auditores. Los
resultados muestran que una legislación más dura no es la panacea para solucionar los problemas y limitaciones que
está presentando el desarrollo de estos mercados alternativos bursátiles y sugieren que el equilibrio y permanente ajuste
de los agentes participantes y los mecanismos de control proporcionan resultados satisfactorios
Nuevas aportaciones corológicas para la amenazada Isoetes durieui Bory (Isoetaceae, Pteridophyta) en la provincia de Huelva (Andalucía, España)
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