6,004 research outputs found
Modeling changes in the tidal propagation and its implication for vessel navigation in Guadalquivir estuary ( Spain)
The Port of Seville is an inland harbour located in the Guadalquivir Estuary some 80 km
from the river mouth and is the unique Spanish inland port. Vessel traffic in the estuary is
a relevant economic activity and a suitable trade-off between vessel draught and safety to
prevent ship aground is required and to optimize the port operability. The Guadalquivir is
a mesotidal estuary with tidal range of 2-3 m, an important fraction of the minimum depth
of the navigation waterway (presently 6.5m). Upstream navigation is favoured around
high water as the tide progresses at 12 knots, which is comparable to the vessel speed,
thus allowing greater vessel draughts. Oceanwards navigation of heavy vessels, on the
contrary, is hampered by the tide because a low water is unavoidably met when heading
downstream.
A 3D, high resolution hydrodynamic model has been implemented in the whole estuary to
study the tidal propagation. The model is forced by the oceanic tide at the mouth and
freshwater discharges controlled by an upstream dam at the head. It has been satisfactorily
validated and predicts tidal oscillations with high accuracy (less than 4 cm in amplitude
and 20 min in phase everywhere in the estuary). Based on the model outputs of tidal
heights and currents and using present-day estuary bathymetry, a MATLAB application
has been developed for shipping planning (Vessel Traffic Decision Support System,
VTDSS). The application allows the final users to test different traffic scheduling
scenarios in order to assess the effects on navigational patterns and explore possible
management and policy scenarios under sea level rise and changes in tidal propagation. A
description of the model and an overview of the VTDSS are presented here; the
effectiveness as a decision support tool is demonstrated via the simulated navigation time
of several vessels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
Autoridad Portuaria de Sevill
Quantum localized states in photonic flat-band lattices
The localization of light in flat-band lattices has been recently proposed
and experimentally demonstrated in several configurations, assuming a classical
description of light. Here, we study the problem of light localization in the
quantum regime. We focus on quasi one-dimensional and two-dimensional lattices
which exhibit a perfect flat-band inside their linear spectrum. Localized
quantum states are constructed as eigenstates of the interaction Hamiltonian
with a vanishing eigenvalue and a well defined total photon number. These are
superpositions of Fock states with probability amplitudes given by positive as
well as negative square roots of multinomial coefficients. The classical
picture can be recovered by considering poissonian superpositions of localized
quantum states with different total photon number. We also study the
separability properties of flat band quantum states and apply them to the
transmission of information via multi-core fibers, where these states allow for
the total passive suppression of photon crosstalk and exhibit robustness
against photon losses. At the end, we propose a novel on-chip setup for the
experimental preparation of localized quantum states of light for any number of
photons.Comment: 12 pages, 5 figure
Plan de Comunicación de la Empresa expresArte
El presente Trabajo de Fin de Grado se adscribe a la modalidad profesional de los TFG del Grado en Periodismo que consiste en el desarrollo de un proyecto profesional en cualquier ámbito de la comunicación, ya sea un proyecto periodístico de prensa, radio, televisión o internet o uno relacionado con la comunicación organizacional. En este TFG se ha optado por elaboración de un Plan de Comunicación para la empresa expresArte.Departamento de Historia Moderna, Contemporánea y de América, Periodismo y Comunicación Audiovisual y PublicidadGrado en Periodism
Anti-angiogenic therapy based on the binding receptors
This paper deals with a nonlinear system of partial differential equations modeling the effect of an anti-angiogenic therapy based on an agent that binds specific receptors of the endothelial cells. We study the time-dependent problem as well as the stationary problem associated to it.Ministerio de Ciencia e Innovació
Hydrodynamic changes in Guadalquivir estuary (Spain) due to a hypothetical tidal marsh restoration project
Tidal marsh restoration will be an important management issue in Guadalquivir Estuary in the
near future. The Guadalquivir Estuary has been anthropologically modified several times, the river
is bounded by embankments to protect rice and cotton plantations from tidal inundation, the
meanders have been transformed into straight sections, about 80 % of the original marsh surface
has been lost and approximately one-fourth of the total surface of the estuary is now part of two
protected areas, one of them is a UNESCO, MAB Biosphere Reserve.
A hypothetical restoration of tidal marshes will benefits different species and functions based on
location, elevation, adjacent habitats, degree of hydrodynamic connectivity and would reduce the
present high levels of turbidity. The restoration projects should be accompanied by studies for a
better understanding of the environmental changes expected.
A Large-scale construction of tidal marsh will change tidal dynamics, modify the tidal inundation
regime and the freshwater flow over the surrounding areas. A hydrodynamic model has been
developed to study changes in the tidal propagation and the flow regime due to a hypothetical
marsh restoration.
The model has been calibrated and the output has been validated with in situ water elevation and
good agreement between modelled and real measurements have been obtained. A sensitivity test
changing the size, locations from the estuary mouth and depth has been carried out to highlights
impacts over the tidal propagation, flow regime, salinity intrusion and the tidal inundation regime.
Our preliminary results show that the tidal elevation and the current speed will be considerably
affected in the estuary. The model open the possibility to study interactions among the tidal marsh
restoration project, Seville port operations, fisheries and agricultural activities. The numerical
model will be a powerful tool in restoration projects in a complex socio-ecological system.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
Autoridad Portuaria de Sevill
Ciclos integrales de biomasa y desarrollo local. Experiencias aplicadas
Históricamente, la gestión de la biomasa ha constituido una fuente básica de energía y ha contribuido a generar empleo y actividad económica. La difusión los combustibles fósiles y la ampliación de la red eléctrica restringieron el uso de la biomasa (fundamentalmente leña). En otros contextos territoriales este uso se mantuvo y se vio acompañado de importantes innovaciones tecnológicas.Las problemáticas asociadas al consumo de combustibles fósiles han propiciado en la última década un auge de las energías renovables y entre ellas la biomasa. La creación de ciclos integrales de producción y aprovechamiento de biomasa a partir de materiales residuales puede generar interesantes dinámicas favorecedoras del desarrollo local. El artículo, aparte de presentar el estado de la cuestión en la materia, analiza varias de estas experiencias y las ventajas e inconvenientes que suponen
An angiogenesis model with nonlinear chemotactic response and flux at the tumor boundary
In this paper we consider a parabolic problem as well as its stationary counterpart of a model arising in angiogenesis. The problem includes a chemotaxis type term and a nonlinear boundary condition at the tumor boundary. We show that the parabolic problem admits a unique positive global in time solution. Moreover, by bifurcation methods, we show the existence of coexistence states and also we study the local stability of the semi-trivial states.Ministerio de Educación y Cienci
Use of GNSS and a refined GGM (XGM2019e) for determining normal heights in the Imbituba Brazilian Vertical Datum and in the International Height Reference System
This paper aimed to evaluate the use of Global Navigation Satellite System (GNSS) ellipsoidal heights in conjunction with height anomalies provided by Global Geopotential Model (GGM) XGM2019e, refined by Residual Terrain Modelling (RTM) technique, to obtain normal heights in Brazil, referred to the Imbituba Brazilian Vertical Datum (IBVD) and the International Height Reference System (IHRS). For this purpose, a local modelling approach has been analyzed in contrast to the national modeling one on the reference geopotential value. For this, a methodology based on geopotential space was adapted. In the local modeling, two study subregions were defined using the spatial clustering analysis of IBVD and GGM/RTM height anomalies differences outliers. The parameters have been estimated using three different configurations. In the parameters validation step, Root Mean Square Errors (RMSE) of the discrepancies between transformed and Brazilian official normal heights were calculated. In both subregions more accurate results have been obtained with the local modeling. In the SP1 subregion the accuracy increased tenfold (0.97m to 0.10m) and SP2 improved from 0.39m to 0.17m. For the linkage to the future realization of IHRS, the accuracy analysis was not possible. However, discrepancies between calculated normal heights and Brazilian official normal heights have been analyzed
Implementación de simuladores quirúrgicos en el programa de residencia de oftalmología del Hospital Militar Central Universidad Nueva Granada: una herramienta valiosa en el proceso de enseñanza aprendizaje
Los programas de especialización en Oftalmología en Colombia, presentan falencias importantes en su estructura y organización. Uno de los campos a mejorar es la posibilidad de entrenamiento práctico en el área de cirugía ocular, materia en que la implementación de simuladores quirúrgicos como parte del currículum, se hace necesaria para suplir de alguna manera este déficit inquietante tanto para los docentes como para los residentes en formación (médicos en entrenamiento de especialidad) . El uso de de este avance tecnológico ofrece al residente la oportunidad de tener una practica análoga a la que realizara en su interacción con la realidad, y es un método de enseñanza y aprendizaje efectivo en el fin de lograr el desarrollo de las habilidades necesarias para este saber hacer. Esta investigación se plantea sobre la base de la bibliografía disponible a nivel mundial
- …