Capacity analysis of suburban rail networks

As is well known, capacity evaluation and the identification of bottlenecks on rail networks are complex issues depending upon several technical elements. This is even more perceptible in metropolitan areas where different services (freight, long distance, metro/regional, etc.) are operated using the same limited infrastructures; as a consequence, these facilities may represent bottlenecks of the rail system since they are often highly utilized and congested. This paper tries to explore the issue of capacity evaluation of complex rail networks, proposing synthetic indicators and analyses for feasibility studies or strategic planning. The presented methodology suggests taking into account the main differences in infrastructure characteristics (e.g. single or double lines, signalling systems, terminus or passing stations, etc.) and rail services (e.g. diverse rolling stock, various frequencies, average distances and number of stops, etc.) in order to propose a general approach applicable for capacity analysis of a network as a whole, hence evaluating the utilization rate and the congestion on both lines and stations. To better explore and validate the methodology, an application to a line of the Naples’ suburban network is presented. The results confirm the applicability and effectiveness of the proposed approach; the outcomes indicate the capacity utilization rate of the considered facilities, pointing out likely bottlenecks and possible actions to improve the system efficiency

Standard-like Models as Type IIB Flux Vacua

We construct new semi-realistic Type IIB flux vacua on $Z_2\times Z_2$ orientifolds with three- and four- Standard Model (SM) families and up to three units of quantized flux. The open-string sector is comprised of magnetized D-branes and is T-dual to supersymmetric intersecting D6-brane constructions. The SM sector contains magnetized D9-branes with negative D3-brane charge contribution. There are large classes of such models and we present explicit constructions for representative ones. In addition to models with one and two units of quantized flux, we also construct the first three- and four-family Standard-like models with supersymmetric fluxes, i.e. comprising three units of quantized flux. Supergravity fluxes are due to the self-dual NS-NS and R-R three-form field strength and they fix the toroidal complex structure moduli and the dilaton. The supersymmetry conditions for the D-brane sector fix in some models all three toroidal K\"ahler moduli. We also provide examples where toroidal K\" ahler moduli are fixed by strong gauge dynamics on the ``hidden sector'' D7-brane. Most of the models possess Higgs doublet pairs with Yukawa couplings that can generate masses for quarks and leptons. The models have (mainly right-) chiral exotics.Comment: 31 page

The silicon stable isotope distribution along the GEOVIDE section (GEOTRACES GA-01) of the North Atlantic Ocean

The stable isotope composition of dissolved silicon in seawater (δ30SiDSi) was examined at 10 stations along the GEOVIDE section (GEOTRACES GA-01), spanning the North Atlantic Ocean (40–60∘ N) and Labrador Sea. Variations in δ30SiDSi below 500 m were closely tied to the distribution of water masses. Higher δ30SiDSi values are associated with intermediate and deep water masses of northern Atlantic or Arctic Ocean origin, whilst lower δ30SiDSi values are associated with DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly, the lowest δ30SiDSi values were observed in the deep and abyssal eastern North Atlantic, where dense southern-sourced waters dominate. The extent to which the spreading of water masses influences the δ30SiDSi distribution is marked clearly by Labrador Sea Water (LSW), whose high δ30SiDSi signature is visible not only within its region of formation within the Labrador and Irminger seas, but also throughout the mid-depth western and eastern North Atlantic Ocean. Both δ30SiDSi and hydrographic parameters document the circulation of LSW into the eastern North Atlantic, where it overlies southern-sourced Lower Deep Water. The GEOVIDE δ30SiDSi distribution thus provides a clear view of the direct interaction between subpolar/polar water masses of northern and southern origin, and allow examination of the extent to which these far-field signals influence the local δ30SiDSi distribution

D-brane Inspired Fermion Mass Textures

In this paper, the issues of the quark mass hierarchies and the Cabbibo Kobayashi Maskawa mixing are analyzed in a class of intersecting D-brane configurations with Standard Model gauge symmetry. The relevant mass matrices are constructed taking into account the constraints imposed by extra abelian symmetries and anomaly cancelation conditions. Possible mass generating mechanisms including perturbative as well as non-perturbative effects are discussed and specific patterns of mass textures are found characterized by the hierarchies of the scales where the various sources contribute. It is argued that the Cholesky decomposition of the mass matrices is the most appropriate way to determine the properties of these fermion mass patterns, while the associated triangular mass matrix form provides a unified description of all phenomenologically equivalent symmetric and non-symmetric mass matrices. An elegant analytic formula is derived for the Cholesky triangular form of the mass matrices where the entries are given as simple functions of the mass eigenstates and the diagonalizing transformation entries. Finally, motivated by the possibility of vanishing zero Yukawa mass entries in several D-brane and F-theory constructions due to the geometry of the internal space, we analyse in detail all possible texture-zeroes mass matrices within the proposed new context. These new texture-zeroes are compared to those existing in the literature while D-brane inspired cases are worked out in detail.Comment: 58 pages, 7 figure

¿Can crossbred animals be used for genomic selection?

Ponencia publicada en ITEA, vol.104La producción en poblaciones “puras” suele tener una baja reproducibilidad en sus descendentes “cruzados”. La selección genómica podría utilizarse para evaluar poblaciones “puras” usando los datos de sus descendientes “cruzados”. Sin embargo, en las poblaciones cruzadas quizás el desequilibrio de ligamiento (LD) no esta restringido a marcadores estrechamente ligados al QTL y los efectos de los marcadores podrían ser específicos de cada población. Estos dos problemas podrían solucionarse utilizando un modelo con los alelos de los SNPs específicos para cada población. Para investigar esta idea usamos un modelo con los efectos de los genotipos de los SNPs (modelo 1) y otro modelo con los efectos de alelos de los SNPs específicos para cada población (modelo 2). Ambos modelos se utilizaron para predecir los valores genéticos de las poblaciones “puras” usando datos F1. Tres situaciones fueron simuladas, en las dos primeras se consideró que las dos poblaciones tenían un mismo origen con una diferencia de 50 y 550 generaciones, respectivamente. En la tercera situación se consideró que las dos poblaciones tenían orígenes distintos. En todos los casos las dos poblaciones generaron una población F1 con un tamaño de 1.000 individuos. Los valores fenotípicos de la F1 fueron simulados con una media de 12 QTL segregando y una heredabilidad de 0.3. En el análisis de la F1 y la población “pura” de validación se escogieron 500 marcadores en segregación. Para estimar el efecto de los SNPs se utilizó el método Bayesiano llamado Bayes-B. La precisión media de los valores genéticos obtenida varió entre 0.789 y 0.718. Sin embargo, se observó que conforme las poblaciones estuvieron más alejadas la precisión disminuyó y el modelo 2 dio valores ligeramente superiores que el modelo 1. Estos resultados sugerirían que los animales cruzados pueden ser utilizados para evaluar poblaciones “puras”. Además modelos con origen específico de población darían mejores resultados.Performance of purebred parents can be a poor predictor of performance of their crossbred descendants. However, in crossbred populations linkage disequilibrium may not be restricted to markers that are tightly linked to the QTL and the effects of SNPs may be breed specific. Both these problems can be addressed by using a model with breed-specific SNP effects. To investigate this idea, we used a model with effects of SNP genotypes (model 1) and a model with breed-specific effects of SNP alleles (model 2) to predict purebred breeding values using F1 data. Three scenarios were considered. In the first two, pure breeds were assumed to have a common origin either 50 or 550 generations ago. In the third scenario, the two breeds did not have a common origin. In all these scenarios, the two breeds were used to generate an F1 with 1,000 individuals. Trait phenotypic values controlled by 12 segregating QTL and with a heritability of 0.30 were simulated for the F1 individuals. Further, 500 segregating markers on a chromosome of 1 Morgan were chosen for analysis in the F1s and in the validation population of purebred. A Bayesian method (Bayes-B) was used to estimate the SNP effects. The accuracy of the predictions was between 0.789 and 0.718. However, the accuracy was lower when the populations were more separate and model 2 gave values slightly higher than model 1. These results suggest that crossbred data could be used to evaluate purebreds and breed specific models could give better results

Linking fish-based biological indicators with hydrological dynamics in a Mediterranean river: Relevance for environmental flow regimes

The relationship between flow dynamics and biological communities becomes especially relevant in Mediterranean rivers. Given their natural variability and growing anthropogenic pressures, their low sections are subjected to multiple impacts. The definition of ecohydrological relationships in Mediterranean rivers may constitute a useful management tool. Historically, fishes were the first group used to assess community-level ecological quality, and different indices and metrics have been proposed. However, up to date many of these indicators have showed to be insensitive to flow regime changes or hydrological alteration. There is therefore a need to deepen into the ecohydrological relationships between such indicators and flow regimes in Mediterranean (and other) rivers. This study presents an analysis of the relationship between interannual flow regimes in the lower section of the Ebro River, defined using a set of daily and hourly hydrological indices, and ecological quality based on fish community, assessed through indices designed to fulfill the Water Framework Directive (WFD) in Europe: the Indices of Biotic Integrity in Catalan rivers (IBICAT2010 and IBICAT2b) and the new European Fish Index (EFI+). In order to identify spatiotemporal patterns, hydrological indices were computed using time periods of different amplitude and ecological quality was obtained in different transects along the river section, even within the same water units or ‘water masses’ (subdivisions of surface waters to fulfill the WFD in Spain). Our results showed that IBICAT2010 was the most correlated with hydrological indices, followed by IBICAT2b and EFI+. The latter showed an almost null correlation with hydrological indices, which may be due to issues associated with the sampling technique, the definition of transects and because it does not uses stream typologies. Correlations among some hydrological and biological indices were observed, with temporal and spatial patterns. On one hand, daily hydrological indices showed relationship with ecological quality when they were computed using between 9 and 36 months of flow records (previous to the sampling date) whereas subdaily indices responded better to periods between 3 and 9 months of records. On the other hand, some sampling transects showed clearer relationships than others, even within the same water mass, which suggests an influence of hydromorphological variability on the obtained ecological quality scores.info:eu-repo/semantics/acceptedVersio

Instanton effects in N=1 brane models and the Kahler metric of twisted matter

We consider locally consistent systems of magnetized D9 branes on an orbifolded six-torus which support N=1 gauge theories. In such realizations, the matter multiplets arise from "twisted" strings connecting different stacks of branes. The introduction of Euclidean 5 branes (E5) wrapped on the six-dimensional compact space leads to instanton effects. For instance, if the system is engineered so as to yield SQCD, a single E5 brane may account for the ADS/TVY superpotential. We discuss the subtle interplay that exists between the annuli diagrams with an E5 boundary and the holomorphicity properties of the effective low-energy action of the N=1 theory. The consistency of this picture allows to obtain information on the Kahler metric of the chiral matter multiplets arising from twisted strings.Comment: 33 pages, 4 figures. V2: improved discussion, clarifyng comments and references added. Version to be published in JHE

Effect of inbreeding on the longevity of Landrace sows

Ponencia publicada en ITEA, vol.104La consanguinidad es un fenómeno biológico de especial relevancia en las especies domésticas, pudiéndose caracterizar tanto en términos de coeficiente de consanguinidad como fraccionando la contribución de cada individuo fundador en coeficientes de consanguinidad parcial (CP). A partir de los registros de longevidad de 4.226 cerdas de raza Landrace, este trabajo se ha centrado en la modelización de los CP bajo modelos Weibull de riesgos proporcionales y su posterior comparación mediante el DIC (deviance information criterion). Se asumieron tres distribuciones a priori distintas para los efectos de CP, resultando la normal asimétrica (DIC = 55.064,6) claramente preferible a la normal simétrica (DIC = 55.069,2) y a la distribución uniforme (DIC = 55.077,9). Se descartó, también, el modelo estándar con la consanguinidad global de cada individuo (DIC = 55.078,4). En el caso del modelo con DIC mínimo, la distribución posterior de los efectos de CP fue claramente asimétrica, con el 85,15% de las estimas afectando negativamente a la longevidad de las cerdas y el 14,85% restante con efecto neutro o incluso positivo. Señalar por último, que la heredabilidad para el carácter longevidad fue de 0,159.Inbreeding is a biological phenomenon of special relevance in domestic species, where the overall inbreeding coefficient can be partitioned in founder-specific partial inbreeding (PI) coefficients. Taking longevity data of 4,226 Landrace sows as starting point, this research proposed alternative parameterization for PI effects under Weibull proportional hazard models, and compared their performance through the deviance information criterion (DIC). Three different a priori distributions were assumed for PI effects, asymmetric normal (DIC = 55,064.6), symmetric normal (DIC = 55,069.2) and flat (DIC = 55,077.9). Additionally, the standard model accounting for the overall inbreeding coefficient was clearly discarded (DIC = 55,078.4). For the model with asymmetric Gaussian prior, the posterior distribution of PI effects was clearly skewed. An 85.15% of the estimates showed negative effect on sow longevity whereas the remaining 14.85% ones had null or even positive effect on sow survival. Estimated heritability was 0.159

Anomalous U(1), holomorphy, supersymmetry breaking and dilaton stabilization

We argue that in certain models with family symmetries the implementation of the alignment mechanism for the supression of the flavor changing neutral currents requires mass matrices with holomorphic zeros in the down quark sector. Holomorphic zeros typically open flat directions that potentially spoil the uniqueness of the supersymmetric vacuum. We then present an anomalous U(1) model without holomorphic zeros in the quark sector that can reproduce the fermion mass hierarchies, provided that $\tan{\beta}$ is of order one. To avoid undesired flavor changing neutral currents we propose a supersymmetry breaking mechanism and a dilaton stabilization scenario that result in degenerate squarks at $M\sim M_{GUT}$ and a calculable low energy spectrum. We present the numerical predictions of this model for the Higgs mass for different values of $M$ and $\tan{\beta}$.Comment: 14 pages, no figures; wording of the abstract is change