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

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

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

Nonminimal supersymmetric standard model with lepton number violation

We carry out a detailed analysis of the nonminimal supersymmetric standard model with lepton number violation. The model contains a unique trilinear lepton number violating term in the superpotential which can give rise to neutrino masses at the tree level. We search for the gauged discrete symmetries realized by cyclic groups which preserve the structure of the associated trilinear superpotential of this model, and which satisfy the constraints of the anomaly cancellation. The implications of this trilinear lepton number violating term in the superpotential and the associated soft supersymmetry breaking term on the phenomenology of the light neutrino masses and mixing is studied in detail. We evaluate the tree and loop level contributions to the neutrino mass matrix in this model. We search for possible suppression mechanism which could explain large hierarchies and maximal mixing angles.Comment: Latex file, 43 pages, 2 figure

Reply to "On scaling solutions with a dissipative fluid"

In this paper we show that the claims in [Class. Quantum Grav. 19 (2002) 3067, gr-qc/0203081] related to our analysis in [Phys. Rev. D 62, 063508 (2000), astro-ph/0005070] are wrong.Comment: 4 pages, uses RevTeX. v2: To appear in Class. Quantum Gra

Moduli in Exceptional SUSY Gauge Theories

The low energy structures of N=1 supersymmetric models with E_6, F_4 and E_7 gauge groups and fundamental irrep matter contents are studied herein. We identify sets of gauge invariant composites which label all flat directions in the confining/Higgs phases of these theories. The impossibility of mapping several of these primary operators rules out previously conjectured exceptional self duals reported in the literature.Comment: 20 pages, harvmac and tables macro

Dynamical supersymmetry breaking from unoriented D-brane instantons

We study the non-perturbative dynamics of an unoriented Z_5-quiver theory of GUT kind with gauge group U(5) and chiral matter. At strong coupling the non-perturbative dynamics is described in terms of set of baryon/meson variables satisfying a quantum deformed constraint. We compute the effective superpotential of the theory and show that it admits a line of supersymmetric vacua and a phase where supersymmetry is dynamically broken via gaugino condensation.Comment: 24 pages, 1 figur

Dynamical supersymmetry breaking in a superstring inspired model

We present a dilaton dominated scenario for supersymmetry breaking in a recently constructed realistic superstring inspired model with an anomalous U(1) symmetry. Supersymmetry is broken via gaugino condensation due to a confining SU(Nc) gauge group in the hidden sector. In particular, we find that by imposing on the model the phenomenological constraint of the absence of observed flavor changing neutral currents, there is a range of parameters related to the hidden sector and the Kahler potential for which we obtain a low energy spectrum consistent with present experimental bounds. As an illustrative example, we derive the low energy spectrum of a specific model. We find that the LSP is the lightest neutralino with a mass of 53 GeV and the lightest Higgs has a mass of 104 GeV.Comment: 13 page

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