Influence of the Compaction Pressure and Sintering Temperature on the Mechanical Properties of Porous Titanium for Biomedical Applications

In the present work, the use of porous titanium is proposed as a solution to the difference in stiffness between the implant and bone tissue, avoiding the bone resorption. Conventional powder metallurgical technique is an industrially established route for fabrication of this type of material. The results are discussed in terms of the influence of compaction pressure and sintering temperature on the porosity (volumetric fraction, size, and morphology) and the quality of the sintering necks. A very good agreement between the predicted values obtained using a simple 2D finite element model, the experimental uniaxial compression behavior, and the analytical model proposed by Nielsen, has been found for both the Young’s modulus and the yield strength. The porous samples obtained by the loose sintering technique and using temperatures between 1000 °C −1100 °C (about 40% of total porosity) are recommended for achieving a suitable biomechanical behavior for cortical bone partial replacement.Ministry of Economy and Competitiveness of the State General Administration of Spain grant MAT2015-71284-

Evaluation of the Role of Functional Constraints on the Integrity of an Ultraconserved Region in the Genus Drosophila

Why gene order is conserved over long evolutionary timespans remains elusive. A common interpretation is that gene order conservation might reflect the existence of functional constraints that are important for organismal performance. Alteration of the integrity of genomic regions, and therefore of those constraints, would result in detrimental effects. This notion seems especially plausible in those genomes that can easily accommodate gene reshuffling via chromosomal inversions since genomic regions free of constraints are likely to have been disrupted in one or more lineages. Nevertheless, no empirical test has been performed to this notion. Here, we disrupt one of the largest conserved genomic regions of the Drosophila genome by chromosome engineering and examine the phenotypic consequences derived from such disruption. The targeted region exhibits multiple patterns of functional enrichment suggestive of the presence of constraints. The carriers of the disrupted collinear block show no defects in their viability, fertility, and parameters of general homeostasis, although their odorant perception is altered. This change in odorant perception does not correlate with modifications of the level of expression and sex bias of the genes within the genomic region disrupted. Our results indicate that even in highly rearranged genomes, like those of Diptera, unusually high levels of gene order conservation cannot be systematically attributed to functional constraints, which raises the possibility that other mechanisms can be in place and therefore the underpinnings of the maintenance of gene organization might be more diverse than previously thought

La comunicación en las sedes webs de las universidades a distancia españolas

Esta investigación analiza la comunicación de las universidades españolas a distancia en sus sedes webs. En los últimos años este tipo de universidades se han multiplicado por cuatro. Hoy en día, las sedes webs de las universidades españolas online se ha convertido en una herramienta primordial para comunicar y atraer a públicos potenciales. Es más, en este tipo de universidades la sede web es el medio por el que los alumnos conocen y establecen una relación con la universidad. El fin de este estudio es profundizar en la forma en que las universidades a distancia se comunican a través de sus sedes webs. Para ello, este trabajo ha utilizado el análisis de contenidos con el fin de estudiar las sedes webs de las universidades españolas a distancia.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Enfermedades y fisiopatías que afectan a la calidad del ajo en postcosecha

Las enfermedades y fisiopatías que afectan al ajo pueden llegar a ocasionar importantes pérdidas en postcosecha, de vital importancia cuando el producto se destina a la exportación a mercados que cada día son más exigentes. En 2008, distintos agricultores de varios municipios de Castilla y León detectaron bulbos de ajo que presentaban síntomas de podredumbre húmeda durante el almacenamiento. Posteriormente, en el año 2009, esta misma podredumbre se observó también en las provincias de Albacete y Cuenca y en muestras procedentes de Córdoba. Hasta la fecha se ha identificado a Fusarium proliferatum como el agente causal de la podredumbre del diente

Host-parasite relationships in root-knot disease of white mulberry

Severe infections of white mulberry feeder roots and heavy soil infestations by Meloidogyne arenaria race 2 were found in southern Spain. This is the first record of M. arenaria on white mulberry in Europe. Morphometric observations, analysis of the esterase electrophoretic pattern, and artificial inoculations of race differentials were used to characterize nematodes. Nematode-induced mature galls were spherical and usually contained one or more females, males, and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode population density (Pi) in a series from 0 to 1,024 eggs and juveniles/cm3 soil and growth of white mulberry seedlings was tested in the greenhouse. A Seinhorst model was fitted to plant height and top fresh weight. Tolerance limits of white mulberry to M. arenaria race 2 for plant height and top fresh weight were, respectively, 1.1 and 1.38 eggs and juveniles/cm3 soil. The minimum relative values for plant height and top fresh weight were 0 at Pi > 64 and Pi > 128 eggs and juveniles/cm3 soil, respectively. Maximum nematode reproduction rate was 435-fold at the lowest Pi. Additional keywords: histopathology, Morus alba, pathogenicity, threshold limitPeer reviewe

Improving randomness characterization through Bayesian model selection

Nowadays random number generation plays an essential role in technology with important applications in areas ranging from cryptography, which lies at the core of current communication protocols, to Monte Carlo methods, and other probabilistic algorithms. In this context, a crucial scientific endeavour is to develop effective methods that allow the characterization of random number generators. However, commonly employed methods either lack formality (e.g. the NIST test suite), or are inapplicable in principle (e.g. the characterization derived from the Algorithmic Theory of Information (ATI)). In this letter we present a novel method based on Bayesian model selection, which is both rigorous and effective, for characterizing randomness in a bit sequence. We derive analytic expressions for a model's likelihood which is then used to compute its posterior probability distribution. Our method proves to be more rigorous than NIST's suite and the Borel-Normality criterion and its implementation is straightforward. We have applied our method to an experimental device based on the process of spontaneous parametric downconversion, implemented in our laboratory, to confirm that it behaves as a genuine quantum random number generator (QRNG). As our approach relies on Bayesian inference, which entails model generalizability, our scheme transcends individual sequence analysis, leading to a characterization of the source of the random sequences itself.Comment: 25 page

Towards the Identification and Classification of Solar Granulation Structures Using Semantic Segmentation

Solar granulation is the visible signature of convective cells at the solar surface. The granulation cellular pattern observed in the continuum intensity images is characterised by diverse structures e.g., bright individual granules of hot rising gas or dark intergranular lanes. Recently, the access to new instrumentation capabilities has given us the possibility to obtain high-resolution images, which have revealed the overwhelming complexity of granulation (e.g., exploding granules and granular lanes). In that sense, any research focused on understanding solar small-scale phenomena on the solar surface is sustained on the effective identification and localization of the different resolved structures. In this work, we present the initial results of a proposed classification model of solar granulation structures based on neural semantic segmentation. We inspect the ability of the U-net architecture, a convolutional neural network initially proposed for biomedical image segmentation, to be applied to the dense segmentation of solar granulation. We use continuum intensity maps of the IMaX instrument onboard the Sunrise I balloon-borne solar observatory and their corresponding segmented maps as a training set. The training data have been labeled using the multiple-level technique (MLT) and also by hand. We performed several tests of the performance and precision of this approach in order to evaluate the versatility of the U-net architecture. We found an appealing potential of the U-net architecture to identify cellular patterns in solar granulation images reaching an average accuracy above 80% in the initial training experiments

Desenvolvimento e estrutura da escala dimensional do sentido de vida

En los últimos años ha aumentado considerablemente el interés por identificar factores específicos que pueden influir en nuestra salud, principalmente aspectos como el sentido de vida, la felicidad y la búsqueda de metas. Desde las aproximaciones humanistas y logoterapéuticas, el sentido de vida es, en términos generales, uno de los factores base para una vida sana. En Latinoamérica son muy pocas las pruebas que han sido desarrolladas o validadas para medir el sentido de vida. El propósito de esta investigación fue desarrollar la Escala Dimensional de Sentido del Vida, comprendido como coherencia existencial y propósito vital. El desarrollo de la escala se realizó mediante la construcción del instrumento para evaluar su estructura y sus características psicométricas. Participaron 820 personas, mujeres y varones, entre 20 y70 años de edad.Los resultados sugieren que la prueba presenta una alta consistencia interna y una estructura de dos dimensiones, una que evalúa la coherencia existencial, y la otra, el propósito vital de las personas.In recent years, the interest for identifying specific factors that may influence our health has greatly increased, especially issues like meaning of life, happiness and pursuit of goals. From the humanistic and logotherapeutic approaches, the meaning of life is, in general, a key factor for a healthy life. In Latin America, very few tests have been developed and validated to measure the meaning of life. The purpose of this research was to develop the Dimensional Scale of Sense of Life, understood as existential coherence and purpose in life. The development of the scale was performed by constructing the instrument to assess its structure and psychometric characteristics. 820 people, women and men, participated, aged 20 and 70 years. Results suggest that the test has high internal consistency and a two-dimensional structure, one that assesses the existential coherence, and the other, the life purpose of people.Nos últimos anos vem aumentado consideravelmente o interesse em identificar fatores específicos que podem influir em nossa saúde, principalmente aspectos como o sentido de vida, a felicidade e a procura de metas. Desde as aproximações humanistas e logoterapêuticas, o sentido de vida é, em termos gerais, um dos fatores base para uma vida saudável. Na América Latina são muito poucas as pesquisas realizadas ou validadas para medir o sentido de vida. O propósito desta pesquisa foi desenvolver a Escala Dimensional de Sentido de Vida, compreendido como coerência existencial e propósito vital. O desenvolvimento da escala foi realizado mediante a construção do instrumento para avaliar sua estrutura e suas características psicométricas. Participaram 820 pessoas, homens e mulheres, entre 20 e 70 anos de idade. Os resultados sugerem que o teste apresenta uma alta consistência interna e uma estrutura de duas dimensões, uma que avalia a coerência existencial, e a outra, o propósito vital das pessoas