4,243 research outputs found
Heavy rainfall events and mass movements in the Funchal area (Madeira, Portugal): spatial analysis and susceptibility assessment
The article presents new information on the spatial distribution of intense rainfall and a new map of susceptibility to the formation of mass movements in the mountainous streams of the municipality of Funchal, the capital of the Autonomous Region of Madeira, an archipelago of Portugal. The methodology that was adopted is based on the spatial analysis of weighted overlap of variables, with influence in the occurrence of hydro-geomorphological processes that are at the origin of catastrophic events, marked by the mobilization of solid material towards and along the fluvial channels. Intense precipitations are effectively the main triggering factor of mass movements, which is why their statistical characteristics and local contrasts are analyzed, to integrate this layer of information into the new susceptibility assessment model of mass movements produced in this article. This type of spatialized information is of strategic importance to support the planning of urban expansion, which requires a land use management practice in accordance with the existing risk in the Madeira Island.info:eu-repo/semantics/publishedVersio
Wind Risk Assessment in Urban Environments: The Case of Falling Trees During Windstorm Events in Lisbon
Trees bring many benefits to the urban environment. However, they may also cause hazards to human population, being the major causes of injuries and infrastructural damage during strong wind events. In the city of Lisbon, strong winds rather frequently result in tree falls, depending on the season and meteorological conditions. This paper presents a methodology to analyse tree damage due to strong wind events in urban environments. Each occurrence has been recorded by the Lisbon Fire Brigade and Rescue Services (Regimento de Sapadores Bombeiros de Lisboa - RSBL). Information provided by RSBL relating to the period of 1990-2005 was considered along with hourly wind speed and direction, species, fitossanitary conditions and urban parameters. To ensure that the fallen trees were caused by strong winds, only days with three or more occurrences of fallen trees were selected. It was found that in summer, northerly winds are responsible for 11% of tree falls, with winds from other directions (west, southwest and south) responsible for 5%. From autumn to spring, perturbed weather conditions originating from the west, southwest and south are responsible for 84% of fallen trees. The majority of tree falls occurred when wind speed surpassed 7 m/s in the six hours prior to their fall. Some recommendations to the Civil Protection Agency and the Fire Department are presented to improve the mission of collecting information. This research is a contribution to the assessment of wind risk in Lisbon
Wind risk assessment in urban environments: the case of falling trees during windstorm events in Lisbon
Trees bring many benefits to the urban environment. However, they may also cause hazards to human
population, being the major causes of injuries and infrastructural damage during strong wind events. In the
city of Lisbon, strong winds rather frequently result in tree falls, depending on the season and meteorological
conditions. This paper presents a methodology to analyse tree damage due to strong wind events in urban
environments. Each occurrence has been recorded by the Lisbon Fire Brigade and Rescue Services (Regimento de
Sapadores Bombeiros de Lisboa - RSBL). Information provided by RSBL relating to the period of 1990-2005 was
considered along with hourly wind speed and direction, species, fitossanitary conditions and urban parameters.
To ensure that the fallen trees were caused by strong winds, only days with three or more occurrences of fallen
trees were selected. It was found that in summer, northerly winds are responsible for 11% of tree falls, with
winds from other directions (west, southwest and south) responsible for 5%. From autumn to spring, perturbed
weather conditions originating from the west, southwest and south are responsible for 84% of fallen trees.
The majority of tree falls occurred when wind speed surpassed 7 m/s in the six hours prior to their fall. Some
recommendations to the Civil Protection Agency and the Fire Department are presented to improve the mission
of collecting information. This research is a contribution to the assessment of wind risk in Lisbon
Galaxy Cosmological Mass Function
We study the galaxy cosmological mass function (GCMF) in a semi-empirical
relativistic approach using observational data provided by galaxy redshift
surveys. Starting from the theory of Ribeiro & Stoeger (2003,
arXiv:astro-ph/0304094) between the mass-to-light ratio, the selection function
obtained from the luminosity function (LF) data and the luminosity density, the
average luminosity and the average galactic mass are
computed in terms of the redshift. is also alternatively
estimated by a method that uses the galaxy stellar mass function (GSMF).
Comparison of these two forms of deriving the average galactic mass allows us
to infer a possible bias introduced by the selection criteria of the survey. We
used the FORS Deep Field galaxy survey sample of 5558 galaxies in the redshift
range and its LF Schechter parameters in the B-band, as well as
this sample's stellar mass-to-light ratio and its GSMF data. Assuming
as the local value of
the average galactic mass, the LF approach results in and .
However, using the GSMF results produces . We chose the latter result as it is less biased. We then obtained
the theoretical quantities of interest, such as the differential number counts,
to calculate the GCMF, which can be fitted by a Schechter function. The derived
GCMF follows theoretical predictions in which the less massive objects form
first, being followed later by more massive ones. In the range
the GCMF has a strong variation that can be interpreted as a higher rate of
galaxy mergers or as a strong evolution in the star formation history of these
galaxies.Comment: In memory of William R. Stoeger (1943-2014). LaTeX, 8 pages, 7
figures. Minor changes to match version sent to publisher. To appear in
"Astronomy and Astrophysics
A Kolmogorov-Smirnov test for the molecular clock on Bayesian ensembles of phylogenies
Divergence date estimates are central to understand evolutionary processes
and depend, in the case of molecular phylogenies, on tests of molecular clocks.
Here we propose two non-parametric tests of strict and relaxed molecular clocks
built upon a framework that uses the empirical cumulative distribution (ECD) of
branch lengths obtained from an ensemble of Bayesian trees and well known
non-parametric (one-sample and two-sample) Kolmogorov-Smirnov (KS)
goodness-of-fit test. In the strict clock case, the method consists in using
the one-sample Kolmogorov-Smirnov (KS) test to directly test if the phylogeny
is clock-like, in other words, if it follows a Poisson law. The ECD is computed
from the discretized branch lengths and the parameter of the expected
Poisson distribution is calculated as the average branch length over the
ensemble of trees. To compensate for the auto-correlation in the ensemble of
trees and pseudo-replication we take advantage of thinning and effective sample
size, two features provided by Bayesian inference MCMC samplers. Finally, it is
observed that tree topologies with very long or very short branches lead to
Poisson mixtures and in this case we propose the use of the two-sample KS test
with samples from two continuous branch length distributions, one obtained from
an ensemble of clock-constrained trees and the other from an ensemble of
unconstrained trees. Moreover, in this second form the test can also be applied
to test for relaxed clock models. The use of a statistically equivalent
ensemble of phylogenies to obtain the branch lengths ECD, instead of one
consensus tree, yields considerable reduction of the effects of small sample
size and provides again of power.Comment: 14 pages, 9 figures, 8 tables. Minor revision, additin of a new
example and new title. Software:
https://github.com/FernandoMarcon/PKS_Test.gi
Context costs and comparative advantages in the telecommunications sector in Portugal and China
This Work Project aims to discuss the Context Costs and Comparative Advantages of the
Telecommunications sector both in Portugal and China. The work was built mostly on primary research
by interviews with relevant people (business persons, University Professors and Agencies directors), and
by economic data publicly available. A list of context costs and comparative advantages was drawn for
each country and possible resolutions suggestions were made in the end. The context costs depend
heavily on the economic situation of the countries and it should be taken into account when assessing
the degree of magnitude of each cost of context. The competitive advantages of each country were
drawn in comparison with one another. Some key results stand out: firstly, Portugal’s costs of context
depend mainly on governmental decisions, uncertainties and instability and China’s cost of context
depend primarily on cultural norms, mainly the Guanxi; second, the telecommunications sector shares
most of its context costs and advantages with other sectors; third, China as an economic power could
use the telecommunications sector as a way to further develop and boost its economy
Modelo de desenvolvimento, agrotóxicos e saúde: um panorama da realidade agrícola brasileira e propostas para uma agenda de pesquisa inovadora.
O modelo agrário hegemônico no Brasil está baseado em monocultivos para exportação que são intensivos em tecnologias mecanizadas e no uso de agrotóxicos. O país tornou-se o principal consumidor mundial de agrotóxicos e é avaliado como o mercado que mais crescerá num futuro próximo. Este trabalho teve como propósito fazer uma avaliação geral da relação entre o modelo agrário brasileiro e os impactos à saúde e ao ambiente decorrentes do uso de agrotóxicos e propor uma agenda de pesquisa para subsidiar o enfrentamento dos problemas apontados que integre os setores comprometidos com a defesa da saúde, do meio ambiente e da segurança e soberania alimentar. Constatou-se e discutiu-se a necessidade de: dar maior visibilidade aos efeitos e aos custos socioambientais e de saúde do modelo predominante; utilizar instrumentos econômicos para incentivar o uso de tecnologias mais limpas e modelos de produção mais saudáveis, compatíveis com a agricultura familiar, e para desestimular os modelos que oferecem mais riscos à saúde e ao ambiente; desenvolver e implementar políticas públicas baseadas em referenciais da economia ecológica e da agroecologia, com a participação de movimentos sociais, das instituições reguladoras e de grupos de pesquisa
PROPOSTA DE INFORMATIZAÇÃO DA GESTÃO, PRESERVAÇÃO E ACESSO A DOCUMENTOS ARQUIVÍSTICOS DE UMA INSTITUIÇÃO DE ENSINO SUPERIOR
Este artigo apresenta o projeto desenvolvido para informatizar a gestão, a preservação e o acesso em longo prazo aos documentos arquivísticos de uma Instituição Pública de Ensino Superior. Esse projeto justifica-se pela necessidade da instituição contemplar em seus processos a constante evolução tecnológica que perpassa por todas as ações humanas, em especial na produção e acumulação documental resultante do registro da execução de suas diversas funções e atividades. Constantemente surgem novos suportes documentais, equipamentos e soluções tecnológicas que devem ser absorvidos pelas instituições para assegurar a produção, a preservação em longo prazo e o acesso aos seus documentos. Como resultado esperado pretende-se ampliar um programa de gestão de documentos arquivísticos, contínuo e institucional, que garanta a confiabilidade, integridade e autenticidade em longo prazo dos documentos arquivísticos da Instituição, em qualquer suporte, incluindo os documentos natos digitais. Assim, contribuindo com a transparência e modernização dos atos administrativos da instituição com sustentabilidade e inovação
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