182 research outputs found
Plant communities as a tool in temporary ponds conservation in SW Portugal
Temporary ponds are seasonal wetlands
annually subjected to extreme and unstable ecological conditions, neither truly aquatic nor truly terrestrial. This habitat and its flora have been poorly studied and documented because of the ephemeral character of the flora, the changeable annual weather that has a great effect on the small, herbaceous taxa and the declining abundance of temporary ponds. The objectives of this study are:
(a)to define plant community diversity in terms of floristic composition of ephemeral wetlands in SW Portugal,
(b) to identify temporary pond types according to their vegetation composition and
(c) to identify those ponds that configure the European community priority habitat (3170* – Mediterranean temporary ponds).
Vegetation sampling was conducted in 29 ponds, identifying 168 species grouped among 15 plant communities. Soil texture, pH, organic C and N
content were measured, but only N and percent of clay appear to be related with the distribution of each community type. The results showed that ephemeral wetlands could be classified into four type: vernal pools, marshlands, deep ponds and disturbed wetlands. Vernal pools correspond to the Mediterranean temporary ponds (3170*), protected as priority hab-
itat under the EU Habitats Directive. Submersed Isoetes species (Isoetes setaceum and Isoetes velatum) represents, together with Eryngium corniculatum, the indicator species for vernal pools. We
identify also indicator plant communities of this priority habitat, namely I. setaceum and E. corniculatum–Baldellia ranunculoides plant communities. In
this region, the conservation of temporary ponds has so far been compatible with traditional agricultural activities, but today these ponds are endangered by the intensification of agriculture and the loss of traditional land use practices and by the development of tourism
Carrageenan-based hydrogels as potential systems for the delivery of PDGF in bone tissue regeneration strategies
[Excerpt] One of the major drawbacks found in most bone tissue engineering (TE) approaches developed so far consists in the lack of strategies to promote vascularization. Some studies have addressed different
issues that may enhance vascularization in TE constructs, most of them involving the use of growth factors that are involved in the restitution of the vascularity in a damaged zone. The use of sustained delivery systems might also play an important role in the reestablishment of angiogenesis. [...]info:eu-repo/semantics/publishedVersio
EGFR/erB-1, HER2/erB-2, CK7, LP34, Ki67 and P53 expression in preneoplastic lesions of bronchial epithelium: an immunohistochemical and genetic study
A prognostic interpretation of preneoplastic lesions would have impact in bronchial carcinoma early diagnosis and through the study of Erb-B family receptors as they have an important role in lung carcinogenesis. The existence of drugs as tyrosine kinase inhibitors stressed the importance of studying gene alterations for selected chemoprevention schemes and characterization of carcinogenesis. Bronchial preneoplastic lesions were characterized by immunohistochemistry using the antibodies LP34 (high weigh molecular cytokeratin), CK7, chromogranin A, Ki67, p53, C-erbB-2 and EGFR. HER2 and EGFR gene copy number was also evaluated by fluorescent in situ hybridization in those lesions. The expected results defined the origin cell for basal cell hyperplasia and squamous metaplasia as adaptative lesions and dysplasia. By known experiences and published data, beyond the stem cell, the spectral evolution of bronchial preneoplastic lesions was demonstrated by characterizing basal cells (LP34) and their neoplastic potentiality. Dysplasias showed a higher expression of EGFR, Ki67 and p53 with a stepwise increase with the gravity of the respective grading. C-erbB-2 immunohistochemical overexpression was a rare event in preneoplastic lesions. Polysomy was the main mechanism for EGFR and HER2/neu higher gene copy number and together with increased proliferation index (Ki67) will account to preview bronchial carcinogenesis.info:eu-repo/semantics/publishedVersio
Floristic patterns in Isoeto-Nanojuncetea communities on the Iberian Peninsula
Oral PresentationN/
Microscopic black hole detection in UHECR: the double bang signature
According to recent conjectures on the existence of large extra dimensions in
our universe, black holes may be produced during the interaction of Ultra High
Energy Cosmic Rays with the atmosphere. However, and so far, the proposed
signatures are based on statistical effects, not allowing identification on an
event by event basis, and may lead to large uncertainties. In this note, events
with a double bang topology, where the production and instantaneous decay of a
microscopic black hole (first bang) is followed, at a measurable distance, by
the decay of an energetic tau lepton (second bang) are proposed as an almost
background free signature. The characteristics of these events and the
capability of large cosmic ray experiments to detect them are discussed.Comment: revised version, 5 figure
A Critical Analysis of Our Experience As Participants in an External Quality Assessment Scheme for Blood Coagulation
info:eu-repo/semantics/publishedVersio
Uso de ferramentas de automação e gerência de dados de tempo e clima para subsidiar estudos agrometeorológicos na Embrapa Amazônia Oriental.
- …