259 research outputs found
El papel de la administración pública en el fomento y planificación del ecoturismo en la montaña española
En esta comunicación se presentan los primeros resultados de un estudio específico sobre el papel de las administraciones públicas en el fomento y planificación del ecoturismo en los destinos de montaña españoles. Los resultados permiten verificar la hipótesis sobre el protagonismo estructural de la gestión pública del turismo en la montaña española y, a su vez, refuerzan las evidencias que avalan la aportación del ecoturismo a los procesos de renovación turística de las áreas de montaña españolas en la última década. En relación con la metodología, dos referencias de interés: el estudio se ha centrado en el análisis de las características e implementación de los instrumentos de fomento y planificación en los últimos quince años, principalmente, con el propósito de constatar el cambio implícito en el planteamiento inicial del estudio; y, por otra parte, el análisis contempla los distintos niveles de gestión pública (administración central y administración regional)
Extensible Hook System for Rendesvouz and Docking of a Cubesat Swarm
The use of cubesat swarms is being proposed for different missions where
cooperation between satellites is required. Commonly, the cube swarm requires
formation flight and even rendezvous and docking, which are very challenging
tasks since they required more energy and the use of advanced guidance,
navigation and control techniques. In this paper, we propose the use of an
extensible hook system to mitigate these drawbacks,i.e. it allows to save fuel
and reduce the system complexity by including techniques that have been
previously demonstrated on Earth. This system is based on a scissor boom
structure, which could reach up to five meters for a 4U dimension, including
three degrees of freedom to place the end effector at any pose within the
system workspace. We simulated the dynamic behaviour of a cubesat with the
proposed system, demonstrating the required power for a 16U cubesat equipped
with one extensible hook system is considered acceptable according to the
current state of the art actuators
Matemáticas de la Historia (o de cómo Clio, celosa de Urania, soñaba con ser de mayor una ciencia exacta)
La exactitud matemática siempre fascinó a los historiadores. Hasta ahora,
las dos opciones, representadas por los extremos del positivismo y el historicismo, consistían
en aplicar un método pseudo-matemático y determinista, o renunciar a las matemáticas,
resignándose a la incertidumbre. Pero en el último siglo las matemáticas han
experimentado una gran revolución gracias a descubrimientos como los teoremas de
Godel, la teoría del caos o la geometría fractal, que difuminan la división entre "ciencias"
y "humanidades". Este artículo explora las repercusiones de estos avances matemáticos
sobre la historia
Loss of wetlands and timberline due to urban sprawl in the basin of the Grijalva River, Mexico
La periurbanización se ha considerado como motor del cambio de uso del suelo y de la pérdida de ecosistemas y de biodiversidad. A partir de esta premisa, la investigación plantea el seguimiento, desde una doble perspectiva, histórica y predictiva, de los cambios en la superficie de los humedales y en la deforestación progresiva entorno a Villahermosa, la urbe más importante de la cuenca del río Grijalva, en el Estado de Tabasco (México). Se han utilizado diferentes métodos: el análisis bibliográfico para el periodo desde la fundación de la ciudad hasta el último tercio del siglo XX, la verificación de fotografías aéreas entre 1984 y 2008 y la modelización de escenarios futuros, entre 2020 y 2040. Desde el periodo colonial hasta mediados del siglo veinte, las inundaciones y la insalubridad dificultaron el crecimiento de la ciudad pese a la transformación de la red hídrica superficial en la cuenca, iniciada mediante la construcción de diques en el siglo XVII. Posteriormente, las elevadas tasas de pérdida de humedales y deforestación (-0.50 y -4.63 %) se incrementaron por la urbanización y el impacto de los programas de producción agropecuaria y petrolización. En los últimos 40 años, el desarrollo periurbano ocasionó la pérdida de 4.008 ha de vegetación arbórea y 289 ha de humedales, con una tendencia a desaparecer 1.449 y 356 ha adicionales respectivamente en el futuro 2040. Estos resultados resaltan la necesidad de rediseñar un programa metropolitano, transdisciplinario y sustentable que respete y actualice las reservas territoriales para regular la periurbanización.Peri-urbanization has been considered to be the driving force of change in land use and the loss of ecosystems and their biodiversity. In view of this premise, the research provides for the follow up, from a double perspective, historical and predictive, on changes in the area of the wetlands and progressive deforestation in Villahermosa, the most important city in the Grijalva River basin, in the State of Tabasco (Mexico). Different methods have been used: the bibliographic analysis for the period since the founding of the city until the last third of the twentieth century, the verification of aerial photographs between 1984 and 2008, and the modelling of future scenarios between 2020 and 2040. Since the Colonial period until the mid-nineteenth century, floods and unhealthy conditions limited the growth of the city despite the transformation of the surface water drainage to basin scale, which was started through the construction of levees in the seventeenth century. Subsequently, high rates of wetland loss and deforestation (-0.50 and -4.63%) increased due to the urbanization and the impact of agricultural production and petroleum programs. In the last 40 years, the fringe development has resulted in the loss of 4,008 ha of timberline vegetation and 289 ha of wetlands, with perhaps an additional 1,449 and 356 ha disappearing by 2040. These results highlight the need to redesign a metropolitan, transdisciplinary and sustainable program that respect and update the land reserves to regulate the urban sprawl
Analysis of Several Productive Development Policies in Uruguay
This paper reviews and assesses some of the Productive Development Policies currently being implemented in Uruguay. Three horizontal and three vertical policies are considered in light of the market and public failures they attempt to address and minimize. Horizontal policies comprise Innovation, Industrial Promotion and Directives for Industrial and Technological Development. Vertical policies include the analysis of Forestry Law, Meat Traceability and the Sustainable Production Project in the agricultural sector
Comparative repeatome analysis on Triatoma infestans Andean and Non-Andean lineages, main vector of Chagas disease
Triatoma infestans is the most important Chagas disease vector in South America. Two main evolutionary lineages, named Andean and non-Andean, have been recognized by geographical distribution, phenetic and genetic characteristics. One of the main differences is the genomic size, varying over 30% in their haploid DNA content. Here we realize a genome wide analysis to compare the repetitive genome fraction (repeatome) between both lineages in order to identify the main repetitive DNA changes occurred during T. infestans differentiation process. RepeatExplorer analysis using Illumina reads showed that both lineages exhibit the same amount of non-repeat sequences, and that satellite DNA is by far the major component of repetitive DNA and the main responsible for the genome size differentiation between both lineages. We characterize 42 satellite DNA families, which are virtually all present in both lineages but with different amount in each lineage. Furthermore, chromosomal location of satellite DNA by fluorescence in situ hybridization showed that genomic variations in T. infestans are mainly due to satellite DNA families located on the heterochromatic regions. The results also show that many satDNA families are located on the euchromatic regions of the chromosomes
Holocentric chromosome evolution in kissing bugs (Hemiptera: Reduviidae: Triatominae): diversification of repeated sequences
Background: The analysis of the chromosomal and genome evolution in organisms with holocentric chromosomes is restricted by the lack of primary constriction or centromere. An interesting group is the hemipteran subfamily Triatominae, vectors of Chagas disease, which affects around 6 to 7 million people worldwide. This group exhibits extensive variability in the number and chromosomal location of repeated sequences such as heterochromatin and ribosomal genes. This paper tries to reveal the significant differences of the repeated sequences among Triatoma species through the use of genomic DNA probes. Methods: We analysed the chromosomal distribution and evolution of repeated sequences in Triatoma species by genomic in situ hybridization (GISH) using genomic DNA probes from two North American Triatoma species. These genomic probes were hybridized both on their own chromosomes and on other Triatoma species from North and South America, with different amounts and chromosome location of C-heterochromatin. The results were compared with those previously described using South American Triatoma genomic probes. Results: We observed two chromosomal hybridization patterns: (i) very intense hybridization signals concentrated on specific chromosomal regions or particular chromosomes; and (ii) lower intensity hybridization signals dispersed along all chromosomes. Self-GISH on T. rubrofasciata and T. dimidiata chromosomes presented strong hybridization signals on all C-heterochromatin regions. However, when we perform genomic cross-hybridizations, only strong signals are detected on the Y chromosome, leaving the C-heterochromatic autosomal regions unmarked. Conclusions: We confirm that repeated DNA of the Y chromosome is shared among Triatoma species and probably represents an ancestral character of the Triatomini tribe. On the contrary, autosomal heterochromatic regions are constituted by species-specific DNA repeats, most probably satDNA families, suggesting that Triatoma speciation involved the amplification of diverse types of autosomal repeats. Molecular characterization of principal repetitive DNAs seems to be an appropriate approach to infer evolutionary relationships in triatomines
Turismo y crisis: el comportamiento del inmobiliario turístico en la montaña española durante la última década. Estudio de casos: la Val d’Aran y Sierra Nevada
En esta comunicación se analiza, como respuesta al enunciado del título, la evolución reciente del parque de viviendas que puede estar vinculado a una función turístico-residencial. Se pretende valorar, a partir de los resultados, el papel que desempeña esta función en el proceso de dinamización local y de renovación de la montaña española como escenario turístico y detectar, asimismo, otros posibles fundamentos de dicha renovación. Se analizan específicamente los datos de los censos de vivienda y las estadísticas de viviendas construidas en destinos significativos previamente seleccionados. El estudio se centra en los últimos quince años, y se realiza a escala municipal. La comarca y el municipio constituyen unidades espaciales operativas idóneas a efectos del tratamiento estadístico de la información obtenida
Secretion by Overexpression and Purification of the Water-Soluble Streptomyces K15 Dd-Transpeptidase/Penicillin-Binding Protein
Though synthesized with a cleavable signal peptide and devoid of membrane anchors, the 262-amino-acid-residue Streptomyces K15 DD-transpeptidase/penicillin-binding protein is membrane-bound. Overexpression in Streptomyces lividans resulted in the export of an appreciable amount of the synthesized protein (4 mg/litre of culture supernatant). The water-soluble enzyme was purified close to protein homogeneity with a yield of 75%. It requires the presence of 0.5 M-NaCl to remain soluble. It is indistinguishable from the detergent-extract wild-type enzyme with respect to molecular mass, thermostability, transpeptidase activity and penicillin-binding capacity
Calcium-calmodulin-dependent protein kinase mediates the intracellular signalling pathways of cardiac apoptosis in mice with impaired glucose tolerance
The impact of cardiac apoptosis in pre-diabetic stages of diabetic cardiomyopathy is unknown. We show that myocytes from fructose-rich diet (FRD) animals exhibit arrhythmias produced by exacerbated Ca2+/calmodulin-protein kinase (CaMKII) activity, ryanodine receptor 2 (RyR2) phosphorylation and sarcoplasmic reticulum (SR) Ca2+ leak. We tested the hypothesis that this mechanism also underlies cardiac apoptosis in pre-diabetes.We generated a pre-diabetic model in FRD mice. FRD mice showed an increase in oxidative stress, hypertrophy and systolic dysfunction. FRD myocytes exhibited enhanced SR Ca2+ spontaneous events in the absence of SR Ca2+ load alterations vs. control-diet (CD) myocytes. In HEK293 cells, hyperglycaemia significantly enhanced [3H]ryanodine binding and CaMKII phosphorylation of RyR2-S2814 residue vs. normoglycaemia. CaMKII inhibition prevented hyperglycaemia-induced alterations. FRD also evoked cardiac apoptosis inWT mice vs. CD-WT mice. Co-treatment with the reactive oxygen species scavenger Tempol prevented FRD-induced apoptosis inWT mice. In contrast, FRD enhanced oxidative stress but not apoptosis in FRD-SR-AIP mice, in which a CaMKII inhibitor is targeted to the SR. FRD produced mitochondrial membrane depolarization inWT mice but not in S2814A mice, in which the CaMKII phosphorylation site on RyR2 was ablated. Furthermore, FRD decreased mitochondrial area, mean Feret diameter and mean SR–mitochondrial distance vs. CD-WT hearts. This remodelling was prevented in AC3I mice, with cardiac-targeted CaMKII inhibition. CaMKII phosphorylation of RyR2, SR Ca2+ leak and mitochondrial membrane depolarization are critically involved in the apoptotic pathway of the pre-diabetic heart. The FRD-induced decrease in SR–mitochondrial distance is likely to additionally favour Ca2+ transit between the two organelles.Facultad de Ciencias MédicasFacultad de Ciencias VeterinariasCentro de Investigaciones Cardiovasculare
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