3,993 research outputs found
Stochastic multi-scale models of competition within heterogeneous cellular populations: simulation methods and mean-field analysis
We propose a modelling framework to analyse the stochastic behaviour of
heterogeneous, multi-scale cellular populations. We illustrate our methodology
with a particular example in which we study a population with an
oxygen-regulated proliferation rate. Our formulation is based on an
age-dependent stochastic process. Cells within the population are characterised
by their age. The age-dependent (oxygen-regulated) birth rate is given by a
stochastic model of oxygen-dependent cell cycle progression. We then formulate
an age-dependent birth-and-death process, which dictates the time evolution of
the cell population. The population is under a feedback loop which controls its
steady state size: cells consume oxygen which in turns fuels cell
proliferation. We show that our stochastic model of cell cycle progression
allows for heterogeneity within the cell population induced by stochastic
effects. Such heterogeneous behaviour is reflected in variations in the
proliferation rate. Within this set-up, we have established three main results.
First, we have shown that the age to the G1/S transition, which essentially
determines the birth rate, exhibits a remarkably simple scaling behaviour. This
allows for a huge simplification of our numerical methodology. A further result
is the observation that heterogeneous populations undergo an internal process
of quasi-neutral competition. Finally, we investigated the effects of
cell-cycle-phase dependent therapies (such as radiation therapy) on
heterogeneous populations. In particular, we have studied the case in which the
population contains a quiescent sub-population. Our mean-field analysis and
numerical simulations confirm that, if the survival fraction of the therapy is
too high, rescue of the quiescent population occurs. This gives rise to
emergence of resistance to therapy since the rescued population is less
sensitive to therapy
A new methodology for quantifying bubble flow rates in deep water using splitbeam echosounders : examples from the Arctic offshore NW-Svalbard (vol 13, pg 267, 2015)
La Gran Guerra 1914-1918: La primera guerra de las imágenes. Ángel Quintana y Jordi Pons (eds.). Girona: Fundació Museu del Cinema-Col·lecció Tomàs Mallol / Universitat de Girona / Ajuntament de Girona, 2016, 254 páginas
A essência ética do direito à informação
Trata de uma reflexão sobre o direito constitucional à informação, observado na sua fundamentalidade material, e os postulados que, emanados da ética, constituem os pontos de referência necessários para pautar a notícia
Harmonization of Transport Data Sources According to INSPIRE Data Specification on Transport Networks
There are numerous sources of data referred to transport from different suppliers, the main one being the Public Administration.
According to the objective of each project, datasets are collected and formatted in a particular way. Each public organization only
covers the area that corresponds to it (municipal, provincial, regional, national), and this results in the network being covered in a
complementary manner, but with no interoperable datasets formats. Conduct studies and projects whose area of study exceeds
more than one scope involve making a first phase of harmonization of data with high costs. These costs could be reduced by
using standard formats and interoperable data sets and services. The European Union has stimulated the process of
standardization and interoperability through INSPIRE Directive (2007/2/EC), which will be fully implemented in 2019 in the
Member States. In this paper a harmonized data model of existing datasets provided by the traffic detectors in urban areas of
Seville and Malaga is proposed, because they are used in many traffic projects and studies. The main objective is subsequent
adaptation to the proposal by the INSPIRE directive specification, taking into account compatibility with the standard format
DATEX II. This process can help to accelerate the transition to the standardized format to which the European Union is directing
transport networks, and data sets associated with them.
© 2016 The Authors. Elsevier B.V. All rights reserved.Ministerio de Economía y Competitividad TRA2012-3693
Recommendations on seismic actions on bridges
The paper describes the main features of a technical Recommendation first draft on Seismic Actions on Bridges, promoted by the Spanish Ministry of Public Works (MOPT). Although much more research is needed to clarify the seismic behaviour of the vast class of problems present in port structures the current state of the art allows at least a classificaton of subjects and the establishment of minimum requirements to guide the design. Also the use of more refined methods for specially dangerous situations needs some general guidelines that contribute to mantein the design under reasonable safety margins. The Recommendations of the Spanish MOPT are a first try in those directions
Telecommunications Network Planning and Maintenance
Telecommunications network operators are on a constant challenge to provide new services which require ubiquitous broadband access. In an attempt to do so, they are faced with many problems such as the network coverage or providing the guaranteed Quality of Service (QoS). Network planning is a multi-objective optimization problem which involves clustering the area of interest by minimizing a cost function which includes relevant parameters, such as installation cost, distance between user and base station, supported traffic, quality of received signal, etc. On the other hand, service assurance deals with the disorders that occur in hardware or software of the managed network. This paper presents a large number of multicriteria techniques that have been developed to deal with different kinds of problems regarding network planning and service assurance. The state of the art presented will help the reader to develop a broader understanding of the problems in the domain
Don Gerónimo Martinez de Alarcón, Canónigo de la Santa Iglesia de Cordova ... en nombre de las Santas Iglesias Metropolitanas y Catedrales, y de dicho Estado Eclesiástico de estas Coronas de Castilla y León, dize: que muchas veces se han presentado à los Señores Reyes, ... los graves inconvenientes, que se siguen de que los libros Sagrados de el rezo, y servicio de el culto divino, estén reduzidos à Estanco: de modo, que su impression y venta, aya de correr por mano de el Convento de San LorenÇo el Real de el Escorial ...Sea, Señor, ... franqueando à todos la impression, y venta libre de los libros de el rezo ...
Precede al tít.: "Señor"Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010En la h. consta el año 166
Potential contribution of distant sources to airborne Betula pollen levels in Northeastern Iberian Peninsula
We acknowledge the financial support of the European Commission for ENV4-CT98-0755; the Spanish Government for CGL2004-21166-E, CGL2005-07543/CLI, CGL2009-11205, CGL2012-39523-C02-01/CLI, CGL2012-39523-C02-02, CGL2016-75996-R, CTM2017-89565-C2-1, CTM2017-89565-C2-2, and CSD 2007-00067; the Catalan Government for 2005SGR00519, 2009SGR1102, and 2017SGR1692; Diputacio de Tarragona; Servei Meteorologic de Catalunya; Sociedad Espanola de Alergologia e Inmunologia Clinica (SEAIC); Laboratorios LETI PHARMA; Societat Catalana d'Allergia i Immunologia Clinica (SCAIC); J Uriach y Compania; S.A. This research contributes to the Maria de Maeztu Programme for Units of Excellence of the Spanish Ministry of Science and Innovation (CEX2019-000940-M). The authors gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for their HYSPLIT transport and dispersion model and the synoptic charts used in this publication.Betula (birch) pollen is one of the most important causes of respiratory allergy in Northern and Central Europe. While
birch trees are abundant in Central, Northern, and Eastern Europe, they are scarce in the Mediterranean territories, especially
in the Iberian Peninsula (IP), where they grow only in the northern regions and as ornamental trees in urban
areas. However, the airborne birch pollen patterns in Catalonia (Northeastern IP) show abrupt high concentrations in
areas with usually low local influence. The intensity of the derived health problems can be increased by outbreaks due
to long-range pollen transport. The present work evaluates the different potential contributions to Catalonia from the
main source regions: Pyrenees, Cantabria, and the forests of France and Central Europe. To this end, we computed the
Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectories of air masses associated with the
main Betula pollen peaks occurring simultaneously over different Catalan monitoring stations, and we studied their
provenance over a 15-year period. The Vielha aerobiological station on the northern slopes of the Central Pyrenees
was used to identify the dates of the pollen season in the Pyrenean region. In order to better understand the role of
the Pyrenees, which is the nearest of the four birch forested regions, we classified the pollen peaks in the other Catalan
stations into three groups based on the relationship between the peak and the pollen season in the Pyrenees. Our analysis
of back-trajectory residence time, combined with the associated pollen concentration, reveals that two principal
routes other than the Pyrenean forest sustain the northerly fluxes that enter Catalonia and carry significant concentrations
of Betula pollen. This study has also allowed quantifying the differentiated contributions of the potential source regions. In addition, theWeather Research Forecast (WRF) mesoscale model has been used to study three specific episodes.
Both models, HYSPLIT and WRF, complement each other and have allowed for better understanding of the
main mechanisms governing the entry of birch pollen to the region.European Commission
European Commission Joint Research Centre ENV4-CT98-0755Spanish GovernmentEuropean Commission CGL2004-21166-E
CGL2005-07543/CLI
CGL2009-11205
CGL2012-39523-C02-01/CLI
CGL2012-39523-C02-02
CGL2016-75996-R
CTM2017-89565-C2-1
CTM2017-89565-C2-2
CSD 2007-00067Diputacio de TarragonaSociedad Espanola de Alergologia e Inmunologia Clinica (SEAIC)Laboratorios LETI PHARMASocietat Catalana d'Allergia i Immunologia Clinica (SCAIC)J Uriach y CompaniaMaria de Maeztu Programme for Units of Excellence of the Spanish Ministry of Science and Innovation CEX2019-000940-MCatalan Government 2005SGR00519
2009SGR1102
2017SGR169
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