847 resultados para Ecosystem functioning
Resumo:
Studies of soil-water dynamics using toposequences are essential to improve the understanding of soil-water-vegetation relationships. This study assessed the hydro-physical and morphological characteristics of soils of Atlantic Rainforest in the Parque Estadual de Carlos Botelho, state of São Paulo, Brazil. The study area of 10.24 ha (320 x 320 m) was covered by dense tropical rainforest (Atlantic Rainforest). Based on soil maps and topographic maps of the area, a representative transect of the soil in this plot was chosen and five soil trenches were opened to determine morphological properties. To evaluate the soil hydro-physical functioning, soil particle size distribution, bulk density (r), particle density (r s), soil water retention curves (SWRC), field saturated hydraulic conductivity (Ks), macroporosity (macro), and microporosity (micro) and total porosity (TP) were determined. Undisturbed samples were collected for micromorphometric image analysis, to determine pore size, shape, and connectivity. The soils in the study area were predominantly Inceptisols, and secondly Entisols and Epiaquic Haplustult. In the soil hydro-physical characterization of the selected transect, a change was observed in Ks between the surface and subsurface layers, from high/intermediate to intermediate/low permeability. This variation in soil-water dynamics was also observed in the SWRC, with higher water retention in the subsurface horizons. The soil hydro-physical behavior was influenced by the morphogenetic characteristics of the soils.
Resumo:
Background: Assertive community treatment (ACT) was reported to be an effective treatment to improve global functioning of ultra-high risk (UHR) adolescents. However, the infl uence of stressful life event (SLE) was not extensively studied which represent our objective. Method: The SLE (encompassing adoption, migration, family member's deceased, sexual or physical abuse, etc.) of 20 UHR adolescents, treated with an ACT model, were rated. 10 adolescents having 0 to 1 SLE (mainly parents' divorce; low SLE group) were compared 10 adolescents with 2 to 5 SLE (high SLE group). The adolescents were assessed at baseline and after treatment with the Health of Nation Outcome Scale for Children and Adolescents (HoNOSCA). The HoNOSCA allowed rating different diffi culties such as behavior, symptoms, disorders and social. Results: First, results on the whole sample indicated signifi cant improvement after ACT (compared to baseline) on the total (P = .04), symptoms (P = .025) and social (P = .009) scores of the HoNOSCA. Second, the improvement on the HoNOSCA's score of the high SLE group were signifi cantly higher for the total (P = .016), symptoms (P = .019) and behavior (P = .033) scores compared to the low SLE group. Discussion/Conclusion: Globally, ACT seems to be an appropriate treatment to enhance global functioning and more specifi cally the social and symptoms diffi culties of UHR adolescents. Additionally, UHR adolescents with a high numbers of SLE were observed to have a better benefi t of the ACT on global, symptoms and behavioral diffi culties.
Resumo:
Major coastal storms, associated with strong winds, high waves and intensified currents, and occasionally with heavy rains and flash floods, are mostly known because of the serious damage they can cause along the shoreline and the threats they pose to navigation. However, there is a profound lack of knowledge on the deep-sea impacts of severe coastal storms. Concurrent measurements of key parameters along the coast and in the deep-sea are extremely rare. Here we present a unique data set showing how one of the most extreme coastal storms of the last decades lashing the Western Mediterranean Sea rapidly impacted the deep-sea ecosystem. The storm peaked the 26th of December 2008 leading to the remobilization of a shallow-water reservoir of marine organic carbon associated with fine particles and resulting in its redistribution across the deep basin. The storm also initiated the movement of large amounts of coarse shelf sediment, which abraded and buried benthic communities. Our findings demonstrate, first, that severe coastal storms are highly efficient in transporting organic carbon from shallow water to deep water, thus contributing to its sequestration and, second, that natural, intermittent atmospheric drivers sensitive to global climate change have the potential to tremendously impact the largest and least known ecosystem on Earth, the deep-sea ecosystem.
Resumo:
OBJECTIVE: Pituitary incidentalomas (PIs) constitute an increasingly clinical problem. While the therapeutic management is well defined for symptomatic non-functioning PIs (NFPIs), a controversy still exists for asymptomatic macro-NFPIs between surgery and a "wait and see" approach. The aim of this study is to compare surgical results between symptomatic and asymptomatic macro-NFPIs. METHODS: We conducted a retrospective study on 76 patients with newly diagnosed symptomatic and asymptomatic macro-NFPIs operated on between 2001 and 2010. We compared age, tumor size and surgical results between these two patient groups. RESULTS: After the initial evaluation, 48 patients were found to be symptomatic. Gross total removal (GTR) rate was significantly higher in asymptomatic (82%) than in symptomatic patients (58%; p=0.03). Gross total removal was strongly associated with Knosp's classification (p=0.01). Postoperative endocrinological impairment was significantly associated with the existence of preoperative symptoms (p=0.03). It was 10 times less frequent in the asymptomatic group. In symptomatic patients, postoperative visual and endocrinological impairment were present in 49% and 78% versus 0% and 14% in asymptomatic patients respectively. CONCLUSIONS: The endocrinological and visual outcome was better in those patients who underwent surgery for asymptomatic tumors. The extent of tumor resection was also significantly greater in smaller tumors. It would therefore be appropriate to offer surgery to patients with asymptomatic macro-NFPIs.
Resumo:
Arbuscular mycorrhizal symbioses occur between fungi and the majority of plant species. They are important for plant nutrition, plant growth, protection from pathogens, plant diversity, nutrient cycling, and ecosystem processes. A key goal in research is to understand the molecular basis of the establishment, regulation, and functioning of the symbiosis. However, lack of knowledge on the genetics of the fungal side of this association has hindered progress. Here, we show how several key, recently discovered processes concerning the genetics of arbuscular mycorrhizal fungi could be essential for ultimately understanding the molecular genetics of this important symbiosis with plants.
Resumo:
The main environmental variables determining the community structure and the functioning of Mediterranean shallow lentic ecosystems are described. These ecosystems are characterized by the unpredictability of their water inputs and the high variability in their water level and physical and chemical composition. Variations in flooding, salinity, and water turnover are determinant in species composition and nutrient dynamics. Taxon-based and size-based approaches to the study of the community structure of aquatic organisms that colonise these ecosystems are also compared. The conventional taxonomic approach, based on the determination of species composition, has been used for the identification of patterns in species richness, distribution and temporal dynamics, and for ecological requirements of species and their potential use as ecological indicators. This taxonbased approach has been compared with a size-based approach, where individuals are classified by their size. Size-based approach gives complementary information about community structure and dynamics, especially when communities are dominated by a single species. The use of size diversity combined with species diversity is suggested for a more complete understanding of community structuring in this type of ecosystem. Detailed examples of two Mediterranean shallow lentic ecosystems, the salt marshes of the Empordà wetlands and the Espolla temporary karstic pond, which differ in hydrology and water origin, are used to discuss the suitability of these different approaches
Resumo:
BACKGROUND: Previous cross-sectional studies report that cognitive impairment is associated with poor psychosocial functioning in euthymic bipolar patients. There is a lack of long-term studies to determine the course of cognitive impairment and its impact on functional outcome. Method A total of 54 subjects were assessed at baseline and 6 years later; 28 had DSM-IV TR bipolar I or II disorder (recruited, at baseline, from a Lithium Clinic Program) and 26 were healthy matched controls. They were all assessed with a cognitive battery tapping into the main cognitive domains (executive function, attention, processing speed, verbal memory and visual memory) twice over a 6-year follow-up period. All patients were euthymic (Hamilton Rating Scale for Depression score lower than 8 and Young mania rating scale score lower than 6) for at least 3 months before both evaluations. At the end of follow-up, psychosocial functioning was also evaluated by means of the Functioning Assessment Short Test. RESULTS: Repeated-measures multivariate analysis of covariance showed that there were main effects of group in the executive domain, in the inhibition domain, in the processing speed domain, and in the verbal memory domain (p<0.04). Among the clinical factors, only longer illness duration was significantly related to slow processing (p=0.01), whereas strong relationships were observed between impoverished cognition along time and poorer psychosocial functioning (p<0.05). CONCLUSIONS: Executive functioning, inhibition, processing speed and verbal memory were impaired in euthymic bipolar out-patients. Although cognitive deficits remained stable on average throughout the follow-up, they had enduring negative effects on psychosocial adaptation of patients.