3,237 research outputs found
Superficial sedimentary stocks and sources of carbon and nitrogen in coastal vegetated assemblages along a flow gradient
Coastal vegetated ecosystems are major organic carbon (OC) and total nitrogen (TN) sinks, but the mechanisms that regulate their spatial variability need to be better understood. Here we assessed how superficial sedimentary OC and TN within intertidal vegetated assemblages (saltmarsh and seagrass) vary along a flow gradient, which is a major driver of sediment grain size, and thus of organic matter (OM) content. A significant relationship between flow current velocity and OC and TN stocks in the seagrass was found, but not in the saltmarsh. OC and TN stocks of the saltmarsh were larger than the seagrass, even though that habitat experiences shorter hydroperiods. Mixing models revealed that OM sources also varied along the flow gradient within the seagrass, but not in the saltmarsh, showing increasing contributions of microphytobenthos (17-32%) and decreasing contributions of POM (45-35%). As well, OM sources varied vertically as microphytobenthos contribution was highest at the higher intertidal saltmarsh (48%), but not POM (39%). Macroalgae, seagrass and saltmarsh showed low contributions. Local trade-offs between flow current velocities, hydroperiod and structural complexity of vegetation must be considered, at both horizontal and vertical (elevation) spatial dimensions, for better estimates of blue carbon and nitrogen in coastal ecosystems.Foundation of Science and Technology of Portugal (FCT)
PTDC/MAR-EST/3223/2014
UID/Multi/04326/2013
FCT UID/MAR/00350/2018
SFRH/BPD/119344/2016info:eu-repo/semantics/publishedVersio
Improving peripheral venous catheterization-related outcomes in oncology patients: an action research study in Portugal
info:eu-repo/semantics/publishedVersio
Difficulties inadaptationand academic performance in higher education: ananalysis in terms of vocational preferences and level of education
[Resumo] Assiste-se a urna maior sensibilidade por parte dos investigadores e autoridades académicas com as dificuldades de adaptaçao e de realizaçao dos estudantes do Ensino Superior. Tais dificuldades sao particularmente sentidas junto dos alunos do 10 ano. Um projecto de investigaçao neste dominio decorre na Universidade do Minho. Neste artigo apresentam- se alguns dados descritivos das dificuldades académicas de urna amostra portuguesa de estudantes do Ensino Superior (n=370), tomando-se quer o facto dos estudantes poderem ou nao estarem a frequentar o curso e estabelecimento de ensino correspondente a sua 1ª escolha vocacional, quer o ano escolar em que os estudantes se encontram. Os resultados sugerem que as dificuldades académicas nas áreas avaliadas nao se diferenciam de acordo com as opçoes vocacionais dos estudantes, muito embora algumas diferenzas sao encontradas quando comparamos os alunos dos anos iniciais e terminais do curso superior que frequentam
Precipitation Maxima and upwelling trends at the NAO Southern Pole during the last millenium
European Geosciences Union General Assembly 2009 (EGU 2009), Vienna, Austria, April 19-24,
200
Crustal growth and deformational processes in the northern
The aim of this article is to present a compilation of available information on
the Évora Massif based on structural mapping, whole-rock geochemistry, recognition
of metamorphic mineral assemblages, and geothermobarometry. In our view, transcurrent
movements responsible for strong orogen-parallel stretching were dominant
and had a major role in the geodynamic evolution of this part of Ossa-Morena zone
(southwest Iberian Massif). Cadomian and Variscan orogenic events separated by a
period of intense rifting were the cause for the composite distribution of zones with
contrasting metamorphic paths, the structural complexity, the variety of lithological
associations, and the sequence of deformation events and magmatism. The proposed
geodynamic reconstruction for this segment of the northern Gondwana continental
margin includes three main stages in chronological order: (1) Neoproterozoic accretion
and continental magmatic arc developing, dismantling, and reworking, followed by late-“orogenic” magmatism; (2) Lower Paleozoic crustal thinning, block tilting,
and mantle upwelling, induced by generalized rifting, leading to the formation of
marine basins with carbonate platform sediments and thick accumulations of volcaniclastic
and terrigenous sediments, contemporaneous with normal and enriched
mid-oceanic ridge basalt–type magmatism; and (3) Upper Paleozoic transpressional
orogenesis resulting from obliquity of convergence and the geometry of the involved
blocks. The third stage includes the tectonic inversion of Lower Paleozoic basins,
crustal thickening, the exhumation of high- to medium-pressure rocks and partial
exhumation of high-grade metamorphic lithologies (controlled by local transtension
and major detachments), the formation of synorogenic basins fi lled with volcanicsedimentary
sequences, and fi nally, the emplacement of late Variscan granodiorites
and granites
Diversity, chemical constituents and biological activities of endophytic fungi isolated from Schinus terebinthifolius raddi
Schinus terebinthifolius Raddi is a medicinal plant widely used for the treatment of
various diseases. The secondary metabolites responsible for the pharmacological properties can
be produced directly by the plant or by endophytic fungi. The objective of this study was to
evaluate the diversity of endophytic fungi of di erent parts of S. terebinthifolius and to identify
chemical compounds produced by endophytes and their antioxidant and antibacterial activities.
For this, fruits, stem bark and roots were dried, ground and placed in fungal growth medium.
The selected endophytes were grown and subjected to extraction with ethyl acetate. DPPH, FRAP,
-carotene bleaching and antimicrobial assays were performed. The phylogenetic tree was elaborated,
encompassing 15 di erent species. The fungal extracts showed hydroxybenzoic acids and 1-dodecanol
as predominant compounds. All fungal extracts exhibited antioxidant activity. The fungal extracts
exhibited bactericidal and bacteriostatic activities against Gram-positive and Gram-negative bacterial
ATCC strains and against methicillin-resistant nosocomial bacteria. Among the 10 endophytic
fungi evaluated, the extract of the fungus Ochrocladosporium elatum showed higher phenolic content
and exhibited higher antioxidant and antibacterial activities in all tests. Together, the results increase
the known diversity of S. terebinthifolius endophytic fungi, secondary metabolites produced and their
antioxidant and antibacterial activities.Thisworkwas supported by grants fromFoundation to Support to Fundação deApoio aoDesenvolvimento do Ensino, Ciência e Tecnologia do Estado deMato Grosso do Sul (FUNDECT), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).info:eu-repo/semantics/publishedVersio
Sobre a reta de Euler.
Neste trabalho iremos provar que baricentro, ortocentro e circuncentro sempre est?o alinhado. Este resultado foi descoberto por Euler e ficou conhecido por Reta de Euler
Ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment
Pharmaceuticals are biologically active and persistent substances which have been recognized as a continuing
threat to environmental stability. Chronic ecotoxicity data as well as information on the current
distribution levels in different environmental compartments continue to be sparse and are focused on
those therapeutic classes that are more frequently prescribed and consumed. Nevertheless, they indicate
the negative impact that these chemical contaminants may have on living organisms, ecosystems and
ultimately, public health. This article reviews the different contamination sources as well as fate and both
acute and chronic effects on non-target organisms. An extensive review of existing data in the form of
tables, encompassing many therapeutic classes is presented
Contribution of hospital effluents to the load of pharmaceuticals in urban wastewaters: Identification of ecologically relevant pharmaceuticals
The impact of effluent wastewaters from four different hospitals: a university (1456 beds), a general (350 beds), a pediatric (110 beds) and a maternity hospital (96 beds), which are conveyed to the same wastewater treatment plant (WWTP), was evaluated in the receiving urban wastewaters. The occurrence of 78 pharmaceuticals belonging to several therapeutic classes was assessed in hospital effluents and WWTP wastewaters (influent and effluent) as well as the contribution of each hospital in WWTP influent in terms of pharmaceutical load. Results indicate that pharmaceuticals are widespread pollutants in both hospital and urban wastewaters. The contribution of hospitals to the input of pharmaceuticals in urban wastewaters widely varies, according to their dimension. The estimated total mass loadings were 306 g d− 1 for the university hospital, 155 g d− 1 for the general one, 14 g d− 1 for the pediatric hospital and 1.5 g d− 1 for the maternity hospital, showing that the biggest hospitals have a greater contribution to the total mass load of pharmaceuticals. Furthermore, analysis of individual contributions of each therapeutic group showed that NSAIDs, analgesics and antibiotics are among the groups with the highest inputs.
Removal efficiency can go from over 90% for pharmaceuticals like acetaminophen and ibuprofen to not removal for β-blockers and salbutamol. Total mass load of pharmaceuticals into receiving surface waters was estimated between 5 and 14 g/d/1000 inhabitants.
Finally, the environmental risk posed by pharmaceuticals detected in hospital and WWTP effluents was assessed by means of hazard quotients toward different trophic levels (algae, daphnids and fish). Several pharmaceuticals present in the different matrices were identified as potentially hazardous to aquatic organisms, showing that especial attention should be paid to antibiotics such as ciprofloxacin, ofloxacin, sulfamethoxazole, azithromycin and clarithromycin, since their hazard quotients in WWTP effluent revealed that they could pose an ecotoxicological risk to algae
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