2,250 research outputs found
Filtenna Integration Achieving Ideal Chebyshev Return Losses
This paper demonstrates that it is possible to find an ideal filter response (Chebyshew, Butterworth,..) considering the antenna as the last resonator of a filter under certain circumstances related with the antenna performance and the bandwidth of the filtenna device. If these circumstances are not accomplished, we can achieve excellent performance as well, by means of an iterative process the goal of which is defined by either a filter mask or a classical filter function itself. The methodology is based on the conventional coupling matrix technique for filter design and has been validated by fabricating a microstrip prototype using hairpin resonators and a rectangular patch antenna
High-precision analysis of binary stars with planets. I. Searching for condensation temperature trends in the HD 106515 system
We explore the probable chemical signature of planet formation in the
remarkable binary system HD 106515. The A star hosts a massive long-period
planet with 9 MJup detected by radial velocity. We also refine stellar and
planetary parameters by using non-solar-scaled opacities when modeling the
stars. Methods. We carried out a simultaneous determination of stellar
parameters and abundances, by applying for the first time non-solar-scaled
opacities in this binary system, in order to reach the highest possible
precision. Results. The stars A and B in the binary system HD 106515 do not
seem to be depleted in refractory elements, which is different when comparing
the Sun with solar-twins. Then, the terrestrial planet formation would have
been less efficient in the stars of this binary system. Together with HD
80606/7, this is the second binary system which does not seem to present a
(terrestrial) signature of planet formation, and hosting both systems an
eccentric giant planet. This is in agreement with numerical simulations, where
the early dynamical evolution of eccentric giant planets clear out most of the
possible terrestrial planets in the inner zone. We refined the stellar mass,
radius and age for both stars and found a notable difference of 78% in R
compared to previous works. We also refined the planet mass to mp sini = 9.08
+/- 0.20 MJup, which differs by 6% compared with literature. In addition, we
showed that the non-solar-scaled solution is not compatible with the classical
solar-scaled method, and some abundance differences are comparable to NLTE or
GCE effects specially when using the Sun as reference. Then, we encourage the
use of non-solar-scaled opacities in high-precision studies such as the
detection of Tc trends.[abridged]Comment: 9 pages, 10 figures, A&A accepted. arXiv admin note: text overlap
with arXiv:1507.0812
Improving the value of public RNA-seq expression data by phenotype prediction.
Publicly available genomic data are a valuable resource for studying normal human variation and disease, but these data are often not well labeled or annotated. The lack of phenotype information for public genomic data severely limits their utility for addressing targeted biological questions. We develop an in silico phenotyping approach for predicting critical missing annotation directly from genomic measurements using well-annotated genomic and phenotypic data produced by consortia like TCGA and GTEx as training data. We apply in silico phenotyping to a set of 70 000 RNA-seq samples we recently processed on a common pipeline as part of the recount2 project. We use gene expression data to build and evaluate predictors for both biological phenotypes (sex, tissue, sample source) and experimental conditions (sequencing strategy). We demonstrate how these predictions can be used to study cross-sample properties of public genomic data, select genomic projects with specific characteristics, and perform downstream analyses using predicted phenotypes. The methods to perform phenotype prediction are available in the phenopredict R package and the predictions for recount2 are available from the recount R package. With data and phenotype information available for 70,000 human samples, expression data is available for use on a scale that was not previously feasible
Nonlinear Performance of BAW Filters Including BST Capacitors
This paper evaluates the nonlinear effects occurring in a bulk acoustic wave (BAW) filter which includes barium strontium titanate (BST) capacitors to cancel the electrostatic capacitance of the BAW resonators. To do that we consider the nonlinear effects on the BAW resonators by use of a nonlinear Mason model. This model accounts for the distributed nonlinearities inherent in the materials forming the resonator. The whole filter is then implemented by properly connecting the resonators in a balanced configuration. Additional BST capacitors are included in the filter topology. The nonlinear behavior of the BST capacitors is also accounted in the overall nonlinear assessment. The whole circuit is then used to evaluate its nonlinear behavior. It is found that the nonlinear contribution arising from the ferroelectric nature of the BST capacitors makes it impractical to fulfill the linearity requirements of commercial filters
Expensive Brains: “Brainy” Rodents have Higher Metabolic Rate
Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur
Comportamiento de los déficit financieros: Causa de una ineficiente administración pública estatal y municipal
La Administración Pública se ha materializado como uno de los principales entes de estudio en las áreas de Gobierno por cumplir múltiples funciones en favor a la sociedad, sus recursos, sus políticas y su conformación de la misma, pero a lo largo del tiempo, de los cambios políticos y de las nuevas implantaciones económicas e inclusive mercantiles se ha visto considerablemente afectada. Así, variables como el aumento de la población, la amplia gama de partidos políticos con tendencias o ideologías muy distintas unos de otros, duración o estancia de los gobiernos en el poder, ámbitos políticos y manipulación de estancias u organismos exteriores a los de nuestro país (internacionales) han sido la principal causa del decline político-administrativo, empero destaquemos que principalmente se ha visto reflejado en el aspecto económico.
En las entidades federativas y municipios que conforman a México se han arrojado un sinfín de obstáculos y limitantes que evita tener un equilibrio o estabilidad financiera en favor al progreso comunitario y económico del país
L’avaluació de xarxes que promouen l’educació per al desenvolupament sostenible : el cas de la xarxa europea support
En aquest treball es planteja desenvolupar una estratègia d’ avaluació que promogui la millora del funcionament de la Xarxa Comenius SUPPORT, dintre d’ un paradigma soci-crític que té en compte els valors comuns de la ESD compartits pels participants, les seves visions de la “qualitat”, les activitats concretes, i els productes obtinguts. L’avaluació de la Xarxa Comenius SUPPORT inclou activitats que promouen la reflexió i el canvi conjuntament amb els participants com, (a) establir els “Criteris de Qualitat”, que seran el centre de l’ estratègia d’ avaluació, (b) dissenyar instruments de recollida de dades, (c) elaborar documents per compartir. D’aquesta forma, s’espera obtenir unes reflexions sobre els problemes del funcionament d’ aquest tipus de xarxes, y el desenvolupament d’estratègies per a promoure l’avaluació formativa en aquests contextos per a la EDS
Interactive effects of herbivory and substrate orientation on algal community dynamics on a coral reef
Herbivory is a significant driver of algal community dynamics on coral reefs. However, abiotic factors such as the complexity and orientation of the benthos often mediate the impact of herbivores on benthic communities. We experimentally evaluated the independent and interactive effects of substrate orientation and herbivorous fishes on algal community dynamics on a coral reef in the Florida Keys, USA. We created horizontal and vertical substrates, mimicking the trend in the reduction of vertical surfaces of coral reefs, to assess how algal communities developed either with herbivory (open areas) or without herbivory (herbivore exclosures). We found that substrate orientation was the dominant influence on macroalgal community composition. Herbivores had little impact on community development of vertical substrates as crustose algae dominated these substrates regardless of being in exclosures or open areas. In contrast, herbivores strongly impacted communities on horizontal substrates, with upright macroalgae (e.g., Dictyota spp., articulated coralline algae) dominating herbivore exclosures, while filamentous turf algae and sediment dominated open areas. Outside of exclosures, differences between vertical and horizontal substrates exposed to herbivores persisted despite similar intensity of herbivory. Our results suggest that the orientation of the reef benthos has an important impact on benthic communities. On vertical surfaces, abiotic factors may be more important for structuring algal communities while herbivory may be more important for controlling algal dynamics in flatter areas. Thus, the decline in structural complexity of Caribbean coral reefs and the flattening of reef substrates may fundamentally alter the impact that herbivores have on benthic community dynamics
Documentación y modelización de una hipótesis de reconstrucción del primer molino hidráulico romano de la península ibérica
[EN] The accurate graphic survey of an archaeological site is fundamental for its analysis and research. Furthermore, if this site is to be covered by a building and will not be accessible or visible, its documentation is essential, not only to continue with the research, but also to disseminate and enhance the discoveries. An example of this is the "Hoya de los Molinos" archaeological site in Caravaca de la Cruz (Region of Murcia, Spain). This is where the first mark of the wheel of a Roman vertical watermill in the Iberian Peninsula has been found. This fact is crucial because remains of Roman vertical-wheeled watermills have been found across the Mediterranean but not in the Iberian Peninsula. Moreover, the fact that this watermill still has all its structural elements makes this archaeological site in Caravaca de la Cruz very interesting. Due to these facts, it is essential to disseminate this discovery, so that it can be recognized and considered as archaeological and cultural heritage. To that end, the researchers have carried out a three-dimensional (3D) reconstruction of the most characteristic elements, such as the vertical wheel, the gears that allowed grinding the grain, and the building protecting them. A virtual recreation was carried out, based on the historical and building research, which is displayed in an explanatory video. Furthermore, two reproductions were created: one made to scale of the archaeological site with a 3D printer and another one of the hypothetical structure of the Roman watermill. To achieve this result, historians, archaeologists and engineers have collaborated, thus enabling not only its adequate dissemination, but also its accurate documentation, in an inclusive manner. Thanks to all the work that this paper describes, the Roman watermill found in Caravaca de la Cruz can be known, studied and assessed.[ES] La documentación gráfica y precisa de un yacimiento arqueológico es fundamental para su posterior estudio e investigación. Cuando el yacimiento quede en el subsuelo de un edificio y no sea accessible ni visitable, dicha documentación es imprescindible, no solo para la continuación de la investigación, sino también para poner en valor los hallazgos encontrados. Un ejemplo de ello es el yacimiento arqueológico de “Hoya de los Molinos” en Caravaca de la Cruz (Región de Murcia, España). En la Península Ibérica se ha encontrado la primera impronta de la rueda de un molino vertical hidráulico de época romana. Este hecho es fundamental por dos razones: la primera es que los molinos hidráulicos fueron utilizados por los romanos, no por los árabes como se creyó durante mucho tiempo (hecho que se ha rebatido gracias a los hallazgos arqueológicos); la segunda es que se encontraron restos de molinos hidráulicos en todo el Mediterrráneo, pero no en la Península ibérica. Además, en el yacimiento se hallaron todos los elementos estructurales del molino hidráulico vertical, lo que hace tan interesante este hallazgo. Por los condicionantes descritos es fundamental divulgar el hallazgo para que sea valorado y conocido. Para ello se realizó una reconstrucción tridimensional (3D) de los elementos más característicos, como son la rueda vertical, los engranajes que permitían la molienda de grano y el edificio que los protegía. A tal efecto, se desarrolló una hipotética recreación virtual y se animó en un video explicativo. También se hicieron dos impresiones 3D a escalas diferentes: una de toda la zona estudiada y otra en detalle del molino y sus engranajes. Para realizar todo lo aquí descrito se trabajó con un equipo multidisciplinar que permitió el estudio y reconstrucción adecuados. Historiadores, arqueólogas e ingenieros colaboraron para obtener este resultado haciendo posible, de una manera inclusiva, no solo su correcta divulgación, sino una precisa documentación. Gracias a todo el trabajo descrito en este artículo, el molino hidráulico hallado en Caravaca de la Cruz podrá ser conocido, investigado y valorado.We would like to thank Professor Dr. Robert Spain and the archaeologists in charge of the archaeological site,, María Belén Sánchez González and Juana María Marín
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