4,985 research outputs found
Herramienta SIG para estimar la distancia de visibilidad disponible en carreteras. Análisis de la influencia de la separación de los puntos de cálculo
Se ha desarrollado una herramienta basada en ArcGIS e implementada en .NET para el cálculo, análisis y documentación de la Distancia de Visibilidad Disponible (DVD) en carretera a partir de la trayectoria del vehículo y un Modelo Digital del Terreno (MDT). Esta herramienta se integra en ArcGIS Desktop como una add-in, pudiendo añadirse a cualquier barra de herramientas como un botón. La herramienta propuesta permite determinar si los distintos puntos situados sobre la trayectoria que tiene que recorrer un vehículo son vistos desde la localización en la que se encuentra el vehículo. Para ello, se utiliza la función “GetLineOfSight” de la extensión “3D Analyst” de ArcMap. La herramienta desarrollada se ha utilizado para evaluar la influencia de la equidistancia entre los puntos de cálculo. Se ha determinado la DVD en una carretera de 14,5 km de longitud calculando para diferentes equidistancias (1, 2, 5, 10 y 20 m) y utilizando un MDT de 1 m de resolución.Al Ministerio de Economía y Competitividad por su financiación en el proyecto de investigación TRA2011-25479 (Convocatoria de 2011 de Proyectos de Investigación Fundamental no Orientada del Plan Nacional de I+D+i 2008-2011)
Economía sostenible: teoría y política
[Resumen] La compatibilidad entre crecimiento economico y sostenibilidad ambiental es un gran reto que deben afrontar a medio y largo plazo tanto la politica economica como los ciudadanos y las empresas. En los ultimos años estamos asistiendo en el ambito de los procesos de decisión públicos y privados a la aparicion de nuevos paradigmas en los que la sostenibilidad se ha convertido en una cuestion de justicia intergeneracional que introduce restricciones a dichos procesos de decision. Con el título de Economia sostenible. Teoria y politica, en este libro se analiza el impacto de esos nuevos paradigmas tanto en el ambito de la teoria como en el de la politica economica. Se entiende aqui por economia sostenible el analisis economico con restricciones de sostenibilidad ambiental, en contraposicion a definiciones de ese termino que impone la agenda politica actual, mas amplias pero menos operativas. Se trata asi de abordar cuestiones como la escala optima de la economia en relación con el ecosistema que la sustenta, las reglas de explotacion de recursos naturales, el diseño de impuestos ecologicos optimos o los indicadores que se deben utilizar para medir la sostenibilidad ambiental de un pais. Especial atencion merece en el texto el analisis de la politica economica con restricciones de sostenibilidad. Destacan, en este sentido, el estudio de los procesos de coordinacion entre las politicas fiscal, monetaria y ambiental, o el analisis del papel que desempeñan variables como los tipos de interes en los resultados de las politicas macroeconomicas cuando se pretende respetar el equilibrio ambiental
A methodology to measure sight-hidden dips'parameters.
Highway design standards specify several requirements on available sight distance. Usually, compliance with these standards is ensured during the design phase of a new road.
This is made through geometric calculations that take into account the terrain and the road. In this paper, a procedure for measuring distances in an existing road from georeferenced photographs is proposed. In addition, an estimation of the error committed when using this procedure is made. Distances measured using this procedure arecompared with the ones measured using a Global Navigation Satellite System (GNSS). Distances error is
within the error estimation and is low enough for using it in traffic safety studies. In addition, the procedure is applied to measure several parameters of a sight-hidden dip. This procedure does not need a terrain model to measure these parameters. This is an advantage compared with other existing procedures for estimating the parameters of sight-hidden dips
Fossil group origins V. The dependence of the luminosity function on the magnitude gap
In nature we observe galaxy aggregations that span a wide range of magnitude
gaps between the two first-ranked galaxies of a system (). There
are systems with gaps close to zero (e.g., the Coma cluster), and at the other
extreme of the distribution, the largest gaps are found among the so-called
fossil systems. Fossil and non-fossil systems could have different galaxy
populations that should be reflected in their luminosity functions. In this
work we study, for the first time, the dependence of the luminosity function
parameters on using data obtained by the fossil group origins
(FOGO) project. We constructed a hybrid luminosity function for 102 groups and
clusters at . We stacked all the individual luminosity functions,
dividing them into bins of , and studied their best-fit
Schechter parameters. We additionally computed a relative luminosity function,
expressed as a function of the central galaxy luminosity, which boosts our
capacity to detect differences, especially at the bright end. We find trends as
a function of at both the bright and faint ends of the
luminosity function. In particular, at the bright end, the larger the magnitude
gap, the fainter the characteristic magnitude . We also find
differences at the faint end. In this region, the larger the gap, the flatter
the faint-end slope . The differences found at the bright end support a
dissipationless, dynamical friction-driven merging model for the growth of the
central galaxy in group- and cluster-sized halos. The differences in the faint
end cannot be explained by this mechanism. Other processes, such as enhanced
tidal disruption due to early infall and/or prevalence of eccentric orbits, may
play a role. However, a larger sample of systems with is
needed to establish the differences at the faint end.Comment: 11 pages, 10 figures, accepted for publication in A&
Liver toxicity and risk of discontinuation in HIV/hepatitis C virus-coinfected patients receiving an etravirine-containing antiretroviral regimen: influence of liver fibrosis
Short communication[Abstract] Objectives. The aim of the study was to establish the risk of liver toxicity in HIV/hepatitis C virus (HCV)-coinfected patients receiving etravirine, according to the degree of liver fibrosis.
Methods. A prospective cohort study of 211 HIV-infected patients initiating an etravirine-containing regimen was carried out. HCV coinfection was defined as a positive HCV RNA test, and baseline liver fibrosis was assessed by transient elastography. Hepatotoxicity was defined as clinical symptoms, or an aspartate aminotransferase (AST) or alanine aminotransferase (ALT) value > 5-fold higher than the upper limit of normal if baseline values were normal, or 3.5-fold higher if values were altered at baseline.
Results. Overall, 145 patients (69%) were HCV coinfected, with a lower nadir (165 versus 220 cells/μL, respectively; p = 0.03) and baseline (374 versus 498 cells/μL, respectively; p = 0.04) CD4 count than monoinfected patients. Etravirine was mainly used with two nucleoside reverse transcriptase inhibitors (129; 61%) or with a boosted protease inhibitor (PI) (28%), with no significant differences according to HCV serostatus. Transient elastography in 117 patients (81%) showed a median (range) stiffness value of 8.25 (3.5–69) kPa, with fibrosis stage 1 in 43 patients (37%) and fibrosis stage 4 in 28 patients (24%). During an accumulated follow-up time of 449.3 patient-years (median 548 days), only one patient with advanced fibrosis (50.8 kPa) had grade 3–4 liver toxicity (0.7%). Transaminases changed slightly, with no significant differences compared with baseline fibrosis, and nine and six patients had grade 1 and 2 transaminase increases, respectively. Also, HCV coinfection was not associated with a higher risk of discontinuation (25% discontinued versus 21% of monoinfected patients; p = 0.39, log-rank test) or virological failure (8% versus 12%, respectively; p = 0.4).
Conclusions. Our data suggest that etravirine is a safe option for HIV/HCV-coinfected patients, including those with significant liver fibrosis
Fossil Groups Origins III. The relation between optical and X-ray luminosities
This study is part of the FOssil Groups Origin (FOGO) project which aims at
carrying out a systematic and multiwavelength study of a large sample of fossil
systems. Here we focus on the relation between the optical luminosity (Lopt)
and X-ray luminosity (Lx). Out of a sample of 28 candidate fossil systems, we
consider a sample of 12 systems whose fossil classification has been confirmed
by a companion study. They are compared with the complementary sample of 16
systems whose fossil nature is not confirmed and with a subsample of 102 galaxy
systems from the RASS-SDSS galaxy cluster survey. Fossil and normal systems
span the same redshift range 0<z<0.5 and have the same Lx distribution. For
each fossil system, the Lx in the 0.1-2.4 keV band is computed using data from
the ROSAT All Sky Survey. For each fossil and normal system we homogeneously
compute Lopt in the r-band within the characteristic cluster radius, using data
from the SDSS DR7. We sample the Lx-Lopt relation over two orders of magnitude
in Lx. Our analysis shows that fossil systems are not statistically
distinguishable from the normal systems both through the 2D KS test and the fit
of the Lx-Lopt relation. The optical luminosity of the galaxy system does
strongly correlate with the X-ray luminosity of the hot gas component,
independently of whether the system is fossil or not. We conclude that our
results are consistent with the classical "merging scenario" of the brightest
galaxy formed via merger/cannibalism of other group galaxies, with conservation
of the optical light. We find no evidence for a peculiar state of the hot
intracluster medium.Comment: A&A, 12 pages, 4 figures, 3 tables, typos corr. and paper re-numbe
Accuracy of periodontitis diagnosis obtained using multiple molecular biomarkers in oral fluids: A systematic review and meta‐analysis
Aim
To determine the accuracy of biomarker combinations in gingival crevicular fluid (GCF) and saliva through meta-analysis to diagnose periodontitis in systemically healthy subjects.
Methods
Studies on combining two or more biomarkers providing a binary classification table, sensitivity/specificity values or group sizes in subjects diagnosed with periodontitis were included. The search was performed in August 2022 through PUBMED, EMBASE, Cochrane, LILACS, SCOPUS and Web of Science. The methodological quality of the articles selected was evaluated using the QUADAS-2 checklist. Hierarchical summary receiver operating characteristic modelling was employed to perform the meta-analyses (CRD42020175021).
Results
Twenty-one combinations in GCF and 47 in saliva were evaluated. Meta-analyses were possible for six salivary combinations (median sensitivity/specificity values): IL-6 with MMP-8 (86.2%/80.5%); IL-1β with IL-6 (83.0%/83.7%); IL-1β with MMP-8 (82.7%/80.8%); MIP-1α with MMP-8 (71.0%/75.6%); IL-1β, IL-6 and MMP-8 (81.8%/84.3%); and IL-1β, IL-6, MIP-1α and MMP-8 (76.6%/79.7%).
Conclusions
Two-biomarker combinations in oral fluids show high diagnostic accuracy for periodontitis, which is not substantially improved by incorporating more biomarkers. In saliva, the dual combinations of IL-1β, IL-6 and MMP-8 have an excellent ability to detect periodontitis and a good capacity to detect non-periodontitis. Because of the limited number of biomarker combinations evaluated, further research is required to corroborate these observationsThis study was funded by the Instituto de Salud Carlos III (ISCIII) through the project PI21/00588 and co-funded by the European UnionS
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