77 research outputs found
Species traits, patch turnover and successional dynamics: when does intermediate disturbance favour metapopulation occupancy?
Research articleBackground: In fragmented landscapes, natural and anthropogenic disturbances coupled with successional processes
result in the destruction and creation of habitat patches. Disturbances are expected to reduce metapopulation
occupancy for species associated with stable habitats, but they may benefit species adapted to transitory habitats by
maintaining a dynamic mosaic of successional stages. However, while early-successional species may be favoured by
very frequent disturbances resetting successional dynamics, metapopulation occupancy may be highest at intermediate
disturbance levels for species with mid-successional habitat preferences, though this may be conditional on
species traits and patch network characteristics. Here we test this ‘intermediate disturbance hypothesis’ applied to
metapopulations (MIDH), using stochastic patch occupancy simulation modelling to assess when does intermediate
disturbance favour metapopulation occupancy. We focused on 54 virtual species varying in their habitat preferences,
dispersal abilities and local extinction and colonization rates. Long-term metapopulation dynamics was estimated in
landscapes with different habitat amounts and patch turnover rates (i.e. disturbance frequency).
Results: Equilibrium metapopulation occupancy by late-successional species strongly declined with increasing
disturbance frequency, while occupancy by early-successional species increased with disturbance frequency at low
disturbance levels and tended to level-off thereafter. Occupancy by mid-successional species tended to increase
along with disturbance frequency at low disturbance levels and declining thereafter. Irrespective of habitat preferences,
occupancy increased with the amount of habitat, and with species dispersal ability and colonisation efficiency.
Conclusions: Our study suggests that MIDH is verified only for species associated with mid-successional habitats.
These species may be particularly sensitive to land use changes causing either increases or decreases in disturbance
frequency. This may be the case, for instance, of species associated with traditional agricultural and pastoral mosaic
landscapes, where many species disappear either through intensification or abandonment processes that change
disturbance frequencyinfo:eu-repo/semantics/publishedVersio
Roadmap for Mine Action Robotic Technology Development
This paper presents some of the AMI-02 project preliminary work. The project is being developed by Integrators for Robotic Systems (IntRoSys) with funding from the Portuguese National Defence Ministry. The strong bond between Portugal and some African countries (i.e., former Portuguese colonies) is the main drive for the application of this project
An R package for simulating metapopulation dynamics and range expansion under environmental change
The metapopulation paradigm is central in ecology and conservation biology to understand the dynamics of spatially-structured populations in fragmented landscapes. Metapopulations are often studied using simulation modelling, and there is an increasing demand of user-friendly software tools to simulate
metapopulation responses to environmental change. Here we describe the MetaLandSim R package, mwhich integrates ideas from metapopulation and graph theories to simulate the dynamics of real and virtual metapopulations. The package offers tools to (i) estimate metapopulation parameters from
empirical data, (ii) to predict variation in patch occupancy over time in static and dynamic landscapes, either real or virtual, and (iii) to quantify the patterns and speed of metapopulation expansion into empty landscapes. MetaLandSim thus provides detailed information on metapopulation processes, which can be easily combined with land use and climate change scenarios to predict metapopulation dynamics and range expansion for a variety of taxa and ecological systems
Translation and validation of two questionnaires assessing fear of flying for Portuguese language
The aim of this study was to translate the FAS and FAM into Portuguese language and to assess its internal consistency, convergent and divergent validities, in a sample of Portuguese speaking population. Both scales were validated in 960 individuals, 890 from the general population and 70 flying phobics. The psychometric methods used were exploratory factor analysis with varimax rotation for factor structure, Cronbach’s α coefficient for internal consistency, Pearson’s correlations for divergent and convergent validities, and finally Mann-Whitney test also for divergent validity. Results confirmed FAS-PT as a 3 factor model and FAM-PT as a 2 factor model, like the original versions. Cronbach’s α coefficient showed excellent values for FAS-PT (.99) and FAM-PT (.97). Convergent validity showed a strong correlation in both scales, with r values between .75 and .87. In opposite, divergent validity presented a poor correlation in both scales, with r values between .28 and .38. The validity and reliability of these scales were established, enabling their use within Portuguese language speakers, for investigation and clinical settings. Nevertheless, this study should be replicated in other samples and other forms of validity should be explored.
Integrated Omics analysis of pig muscle metabolism under the effects of dietary Chlorella vulgaris and exogenous enzymes
Monogastric feeding is dependent on costly conventional feedstuffs. Microalgae such as Chlorella
vulgaris are a sustainable alternative; however, its recalcitrant cell wall hinders monogastric digestion.
Carbohydrate Active Enzyme (CAZyme) supplementation is a possible solution. The objective of this
work was to evaluate the effect of 5% dietary C. vulgaris (CV) and enzymatic supplementation (CV + R—
Rovabio® Excel AP; CV + M—four CAZyme mix) on muscle transcriptome and proteome of finishing
pigs, in an integrated approach. Control pigs increased the abundance of contractile apparatus (MYH1,
MYH2, MYH4) and energy metabolism (CKMT1, NDUFS3) proteins, demonstrating increased nutrient
availability. They had increased expression of SCD, characteristic of increased glucose availability,
via the activation of SREBP-1c and ChREBP. CV and CV + R pigs upregulated proteolytic and apoptotic
genes (BAX, DDA1), whilst increasing the abundance of glucose (UQCRFS1) and fatty acid catabolism
(ACADS) proteins. CV + R pigs upregulated ACOT8 and SIRT3 genes as a response to reduced nutrient
availability, maintaining energy homeostasis. The cell wall specific CAZyme mix, CV + M, was able
to comparatively reduce Omics alterations in the muscle, thereby reducing endogenous nutrient
catabolism compared to the CV + R and CVinfo:eu-repo/semantics/publishedVersio
Combining distribution modelling and non-invasive genetics to improve range shift forecasting
Forecasting species range shifts under climate change is critical to adapt conservation strategies to future environmental conditions. Ecological niche models (ENMs) are often used to achieve this goal, but their accuracy is limited when species niches are inadequately sampled. This problem may be tackled by combining ENM with field validation to fine-tune current species distribution, though the traditional methods are often time-consuming and the species ID inaccurate. Here we combine ENM with novel field validation methods based on non-invasive genetic sampling to forecast range shifts in the globally near-threatened Cabrera vole (Microtus cabrerae). Using occurrence records mapped at 10 km × 10 km resolution, we built the first ENM (ENM1) to estimate the current species distribution. We then selected 40 grid squares with no previous data along the predicted range margins, and surveyed suitable habitats through presence-sign searches. Faecal samples visually assigned to the species were collected for genetic identification based on the mitochondrial cytochrome-b gene, which resulted in 19 new grid squares with confirmed presence records. The second model (ENM2) was built by adding the new data, and species distribution maps predicted by each model under current and future climate change scenarios were compared. Both models had high predictive ability, with strong influence of temperature and precipitation. Although current distribution ranges predicted by each model were quite similar, the range shifts predicted under climate change differed greatly when using additional field data. In particular, ENM1 overlooked areas identified as important by ENM2 for species conservation in the future. Overall, results suggest that combining ENM with non-invasive genetics may provide a cost-effective approach in studies regarding species conservation under environmental change
DOENÇA DE DARIER COMEDÓNICA
Darier disease is an autosomal dominant dermatosis caused by the mutation of the ATP2A2 gene. There are rarer clinical variants showing atypical skin lesions like the hypertrophic, vesicobollous, hypopigmented, and comedonal subtypes. We present the case of a 28-years-old healthy man with more than hundred pruritic open comedone-like hyperkeratotic dark papules of the upper and lower back. Histological examination showed dilated follicular infundibulum, containing keratotic material, suprabasal acantholysis and dyskeratotic cells compatible with comedonal Darier disease. There are less than 10 published cases of this clinical and histological subtype.A doença de Darier é uma dermatose autossómica dominante causada por uma mutação do gene ATP2A2. Existem várias variantes clínicas menos frequentes nomeadamente as formas de doença de Darier hipertrófica, vesiculobolhosa, hipopigmentada e a variante comedónica. Apresentamos o caso de um homem saudável de 28 anos de idade, com mais de cem pápulas hiperqueratosicas pruriginosas, simulando comedões abertos, localizadas ao dorso e flancos. O exame histológico mostrou o infundibulo folicular dilatado, contendo rolhões queratina, acantólise suprabasal e células disceratósicas sendo compatível com a doença Darier do tipo comedónica. Existem menos de 10 casos publicados desta variante clínica e histológica
Open source technologies involved in constructing a web-based football information system
The current information systems and match analysis software associated to professional football output a huge amount of statistics. Many football professionals are particularly interested in real time information about
the tactical plan occurring during the match, and the relations between that
information and what was prepared in the training sessions. It is fundamental to
have on the bench, and on-the-fly, the most relevant information each time they have to take a decision. In this paper, we present a set of open source technologies involved in building a multi-platform web based integrated football information system, supported in three main modules: user interfaces,
databases, and the tactical plan detection and classification. We show that the selected technologies are suitable for those modules, allowing field occurrences to trigger meaningful information
Expression of genes controlling fat deposition in two genetically diverse beef cattle breeds fed high or low silage diets
Articles in International JournalsBackground: Both genetic background and finishing system can alter fat deposition, thus indicating their influence
on adipogenic and lipogenic factors. However, the molecular mechanisms underlying fat deposition and fatty acid
composition in beef cattle are not fully understood. This study aimed to assess the effect of breed and dietary
silage level on the expression patterns of key genes controlling lipid metabolism in subcutaneous adipose tissue
(SAT) and longissimus lumborum (LL) muscle of cattle. To that purpose, forty bulls from two genetically diverse
Portuguese bovine breeds with distinct maturity rates, Alentejana and Barrosã, were selected and fed either low
(30% maize silage/70% concentrate) or high silage (70% maize silage/30% concentrate) diets.
Results: The results suggested that enhanced deposition of fatty acids in the SAT from Barrosã bulls, when
compared to Alentejana, could be due to higher expression levels of lipogenesis (SCD and LPL) and β-oxidation
(CRAT) related genes. Our results also indicated that SREBF1 expression in the SAT is increased by feeding the low
silage diet. Together, these results point out to a higher lipid turnover in the SAT of Barrosã bulls when compared
to Alentejana. In turn, lipid deposition in the LL muscle is related to the expression of adipogenic (PPARG and
FABP4) and lipogenic (ACACA and SCD) genes. The positive correlation between ACACA expression levels and total
lipids, as well trans fatty acids, points to ACACA as a major player in intramuscular deposition in ruminants.
Moreover, results reinforce the role of FABP4 in intramuscular fat development and the SAT as the major site for
lipid metabolism in ruminants.
Conclusions: Overall, the results showed that SAT and LL muscle fatty acid composition are mostly dependent on
the genetic background. In addition, dietary silage level impacted on muscle lipid metabolism to a greater extent
than on that of SAT, as evaluated by gene expression levels of adipogenic and lipogenic factors. Moreover, the
response to diet composition evaluated through mRNA levels and fatty acid composition showed interesting
differences between Alentejana and Barrosã bulls. These findings provide evidence that the genetic background
should be taken into account while devising diet-based strategies to manipulate fatty acid composition of beef
cattle tissues
Inferring past refugia and range dynamics through the integration of fossil, niche modelling and genomic data
Aim: Reconstructing species' glacial refugial history and demographic changes over
time has greatly relied on comparing inferences from multiple methods while not sufficiently
acknowledging their limitations. Here, we aim to integrate as fully as possible
complementary methods in ecology, genomics and palaeobiology to improve the reconstruction
of species biogeographical history.
Location: South-western
Europe.
Taxon: Cabrera vole (Microtus cabrerae).
Methods: We compiled and mapped the raw fossil data of the Cabrera vole for the
Last Glacial Maximum (LGM) and Mid-Holocene
(MH). Alongside, we projected the
calibrated ecological niche model (ENM) of the species' current distribution for the
LGM, the Younger Dryas and the MH. Complementarily, we used previously obtained
Genotyping-by-
Sequencing
data to evaluate the demographic history and range expansion
patterns of all four Evolutionarily Significant Units of the species, in an integrative
framework. Results: ENM-inferred
refugial areas and genomic modelling consistently supported
northern Iberian glacial refugia for the Cabrera vole. This contrasted with the higher
fossil abundance of the species in southern and eastern Iberia and southern France
from the LGM to the MH. Our results suggest that populations in areas with high fossil
abundance went extinct, and were later replaced by northern Iberian populations
such that they did not contribute significantly to the current gene pool.
Main conclusions: Our integrative approach indicates how the range of the Cabrera
vole fluctuated in response to environmental change during and following the LGM.
Despite methodological limitations, the ENM and genomic approaches produced generally
congruent results. Instead, the fossil record may misrepresent the ancestral distribution
of this species and should be considered cautiously for ancestral distribution
reconstruction, considering that it also reflects the fossilization conditions. Overall,
our study supports the idea that integrative approaches are essential to provide an
accurate and well-supported
picture of historical refugial areas and range dynamicsinfo:eu-repo/semantics/publishedVersio
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