15,076 research outputs found
Sustainable forest management of miombo woodlands in Niassa National Reserve, northern Mozambique: a multidisciplinary approach of fire resistance analysis.
Poster presented at XIII World Forestry Congress. Buenos Aires (Argentina). 18 - 23 Oct 2009
Bioclimatic modelling in the holocene and in future warming scenarios in Arbutus unedo L.
Growing forests wildfires in Portugal are an increasing concern since forests in the Mediterranean region are vulnerable to recent global warming. Long-term negative effects are expected on the vegetation with the coming increasing drought. The strawberry tree (Arbutus unedo L.) displays potential to be a successfully business-like cultured in several regions of Portugal and southern Europe, as it is well adapted to climate and soils. In Portugal, this species has been used by local populations particularly for spirit production and for fruit consumption, although it has different possible commercial uses, from processed and fresh fruit production to ornamental, pharmaceutical and chemical applications. In addition, due to its pioneer status, it is valuable for land recovery and desertification avoidance, besides being fire resistant. The available strawberry tree’s data is presence-only. For modelling purposes, a set of placements within the landscape of interest (Portugal) was applied. The species, observed in 318 plots, together with a vector of environmental covariates (7 bioclimatic attributes, slope and altitude) and a defined background were used for modeling purposes. Maxent 3.4.1 was the used software, where the estimated quantity is the probability of the presence of the species, conditioned on the environment. Maxent uses the environmental covariate data from the occurrence records and the background sample, to estimate the ratio between the conditional density of the covariates at the presence sites and the marginal (i.e., unconditional) density of covariates across the study area and so, estimating the relative suitability of one place vs. another. Three different climate scenarios (control run; 2050 and 2070) were tested for two emission scenarios (RCP 4.5 and RCP 8.5, WorldClim), besides the past, 6,000 BP (Mid-Holocene). The reduction of habitat suitable for this species is very significant in the southern regions, even for the best warming scenario (RCP 4.5) in 2050. Central and Northern mountain regions are predicted refuge for this species. Forest policies and management should consider the impact of climate change on the usable areas for forestry, seeing a case-study species particularly adapted to the Mediterranean regions and wildfires, such as strawberry tree. The distribution of the species in the Middle Holocene agrees with previous genetic and fossils studies in the region, which supported two putative refuges for the species since the Last Glacial Maximum and a cryptic refugia in the East-Central mountain region.info:eu-repo/semantics/publishedVersio
Sustainable management of miombo woodlands in the Northern part of Mozambique (Niassa National Reserve - NNR).
Poster presented at Commiting Science to Global Development. Lisbon (Portugal). 29-30 Sep 2009
INJECTABLE HYBRID SYSTEM FOR STRONTIUM LOCAL DELIVERY TO PROMOTE BONE REGENERATION
In bone tissue regeneration strategies, injectable bone substitutes are very attractive since they can
be applied with minimally invasive surgical procedures and can perfectly fill irregular defects created
in cases of trauma, infection or tumor resection. These materials must combine adequate mechanical
properties with the ability to induce new bone formation. Incorporating strontium (Sr) in bone
substitute biomaterials may be a strategy to achieve high Sr concentrations, not in a systemic but in
a local environment, taking advantage of the osteoanabolic and anti-osteoclastic activity of Sr, for
the enhancement of new bone formation. In this context, the aim of the present work was to
evaluate the response of a Sr-hybrid injectable system for bone regeneration, designed by our
group, consisting of hydroxyapatite microspheres doped with Sr and an alginate vehicle crosslinked in
situ with Sr, in an in vivo scenario. Two different animal models were used, rat (Wistar) and sheep
(Merino Branco) critical sized bone defect. Non Sr-doped similar materials (Ca-hybrid) or empty
defects were used as control. Sr-hybrid system led to an increased bone formation in both center
and periphery of a rat critical sized defect compared to a non Sr–doped similar system, where new
bone formation was restricted to the periphery. Moreover newly formed bone was identified as early
as one week after its implantation in a sheep model. After eight weeks, the bone surrounded the
microspheres, both in the periphery and in the center of the defect. Most importantly, the hybrid
system provided a scaffold for cell migration and tissue ingrowth and offered structural support, as
observed in both models. The effective improvement of local bone formation suggests that this might
be a promising approach for bone regeneration, especially in osteoporotic conditions
Lowering the voting age to 16: Young people making a case for political education in fostering voting competencies
The intention of this article is to contribute to the debate about whether the voting age should be lowered
to the age of 16, by examining quantitative and qualitative data collected in a local participation project
with young people in Portugal: questionnaires (N = 961), interviews (N = 3), and focus group discussions
(N = 15). Considering the coexistence of both willingness and reluctance to get engaged in formal politics
– as youngsters often feel ill-equipped politically – it is argued that adequate political education needs to be
provided by schools to enable young people to be confident and knowledgeable voters. We propose that
governments recognise the importance of this area in the school curriculum, in order to enable the young
people’s acquisition of knowledge and skills that can sustain their growth as competent voters. This is crucial
in legitimising democratic representative systems.info:eu-repo/semantics/publishedVersio
Limit theorem for a time-dependent coined quantum walk on the line
We study time-dependent discrete-time quantum walks on the one-dimensional
lattice. We compute the limit distribution of a two-period quantum walk defined
by two orthogonal matrices. For the symmetric case, the distribution is
determined by one of two matrices. Moreover, limit theorems for two special
cases are presented
Chemical abundances for the transiting planet host stars OGLE-TR-10, 56, 111, 113, 132 and TrES-1. Abundances in different galactic populations
We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution
spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111,
113, 132 and TrES-1. The spectra are now used to derive and discuss the
chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni,
Cu and Zn. Abundances were derived in LTE, using 1-D plane-parallel Kurucz
model atmospheres. For S, Zn and Cu we used a spectral synthesis procedure,
while for the remaining cases the abundances were derived from measurements of
line-equivalent widths. The resulting abundances are compared with those found
for stars in the solar neighborhood. Distances and galactic coordinates are
estimated for the stars. We conclude that besides being particularly
metal-rich, with small possible exceptions OGLE-TR-10, 56, 111, 113, 132 and
TrES-1 are chemically undistinguishable from the field (thin disk) stars
regarding their [X/Fe] abundances. This is particularly relevant for the most
distant of the targets, located at up to ~2 Kpc from the Sun. We also did not
find any correlation between the abundances and the condensation temperature of
the elements, an evidence that strong accretion of planetary-like material,
tentatively connected to planetary migration, did not occur.Comment: Accepted for publication in Astronomy & Astrophysics (June 2006
Aprendizaje – servicio en la Universidad Católica Portuguesa Viseu – experiencia piloto
Some of the concepts of Service Learning (SL) are common to the teaching of health-related areas. However, there are many other requisites for a project to be SL such as the developing of student’s commitment to contribute to society and the importance of reflection on the learning experience. In this presentation the application of the SL methodology to Health in the Centro Regional de Viseu of the Universidade Católica Portuguesa, where students from the Integrated Master of Dental Medicine as well as the Bachelors in Management get together to help a senior nursing home to improve the oral health of the residents and the financial management of the home. The project is only half completed so far and there are still goals to accomplish. However, students’ portfolios already show that the 51 students involved in treating about 200 elderly residents are happy to participate in the project. These students are working closely with the Home managers and employees to improve oral health and prevent oral diseases. This pilot intervention is part of a larger project which aims at implementing SL in the Universidade Católica Portuguesa as well as to identify good practices in SL in Portugal.Algunos de los conceptos de la Aprendizaje-Servicio (ApS) son comunes con la enseñanza de muchas de las áreas de la salud. Sin embargo, hay muchos otros requisitos que están presentes en ApS como la toma de conciencia de ser un actor en la resolución de problemas sociales y la reflexión sobre las experiencias de ApS. En esa contribución se presenta la aplicación de la metodologÃa ApS en el Centro Regional de Viseu de la Universidade Católica Portuguesa, onde alumnos del Máster en OdontologÃa e del Master en Gestión se juntarán para ayudar un Residência de Mayores a mejorar la Salud Oral de sus mayores e la gestión financiera la residencia de mayores. El proyecto está en la mitad, pero la satisfacción de los alumnos ya es evidente por el análisis reflexivo que hicieran en sus porfolios. Están involucrados 51 alumnos en ese proyecto, trabajando con la dirección y los auxiliares de esa institución que tiene casi 200 mayores en régimen de internamiento. Esa experiencia piloto es parte de un proyecto más largo que tiene como objetivo implementar la ApS en toda la Universidade Católica Portuguesa y crear un ejemplo de buenas prácticas en ApS en Portugal.info:eu-repo/semantics/publishedVersio
Ballistic heat transport of quantum spin excitations as seen in SrCuO2
Fundamental conservation laws predict ballistic, i.e., dissipationless
transport behaviour in one-dimensional quantum magnets. Experimental evidence,
however, for such anomalous transport has been lacking ever since. Here we
provide experimental evidence for ballistic heat transport in a S=1/2
Heisenberg chain. In particular, we investigate high purity samples of the
chain cuprate SrCuO2 and observe a huge magnetic heat conductivity
. An extremely large spinon mean free path of more than a
micrometer demonstrates that is only limited by extrinsic
scattering processes which is a clear signature of ballistic transport in the
underlying spin model
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