1,902 research outputs found
Treatment of Vascular Dementia: The Route of Prevention
Vascular dementia (VaD), rather than being considered as a univocal nosological entity, should be regarded as a heterogeneous clinical entity which differs in clinical-pathological phenotype as well as in pathophysiological mechanisms, but shares cerebrovascular disease (CVD), resulting from vascular or circulatory pathology, as the cause of dementia. The aim of this review is to discuss VaD treatment focusing particularly on more prevalent ischemic forms. Due to the fact that there are presently no treatments capable of obtaining considerable results once VaD is clinically established, specific emphasis will be given to the therapeutic strategies aimed at the prevention of CVD risk factors. The therapeutic strategies aimed at slowing the progression of the disease will also be discussed
Beamlike models for the analyses of curved, twisted and tapered horizontal-axis wind turbine (HAWT) blades undergoing large displacements
Abstract. Continuous ongoing efforts to better predict the mechanical behaviour of complex beamlike structures, such as wind turbine blades, are motivated by the need to improve their performance and reduce the costs. However, new design approaches and the increasing flexibility of such structures make their aeroelastic modelling ever more challenging. For the structural part of this modelling, the best compromise between computational efficiency and accuracy can be obtained via schematizations based on suitable beamlike elements. This paper addresses the modelling of the mechanical behaviour of beamlike structures which are curved, twisted and tapered in their unstressed state and undergo large displacements, in- and out-of-plane cross-sectional warping, and small strains. A suitable model for the problem at hand is proposed. Analytical and numerical results obtained by its application are presented and compared with results from 3D FEM analyses
A shared database of underground utility lines for 3D mapping and GIS applications
For the purpose of facility management it is very important to have detailed and up-to-date databases of underground utility lines,
but such data are not always available with adequate accuracy. Hence, the need of collecting and organizing suitable information on
underground services is a fundamental issue when dealing with urban data. Besides, by analyzing the process of designing and laying
new underground infrastructures it is possible to implement an efficient and cost-effective approach to integrate and update existing
maps by exploiting the surveying required for the installation of new facilities. It is also important to underline that collecting all the
data in a unique integrated database (and GIS) gives the possibility to share (at least at a local level) the cartographic and thematic
information for an optimal management of underground networks. In this paper, a database (DB) model for archiving the
underground lines data is presented. The structure of the DB has been designed by following the standard methodology for the
modelling of a relational DB, going through successive phases and originating the external, conceptual and logical model. Finally,
preliminary tests have been carried on for parts of the DB to verify quality parameters
T cell expansion from umbilical cord blood without thymic stroma cells after stimulation with SCF, IL-7, AND IL-2
We analyzed in vitro expansion and differentiation of T progenitor cells from umbilical cord blood in the absence of thymic epithelium. The expansion setup is performed in the presence of SCF, IL-7 , and IL -2 with autologous serum .Using CBMCs as initial source , we compared the growth kinetics of several cell populations in either whole CBMC orĂ CD34+ -enriched-, as well as in CD3CD4CD8-depleted expansion assays by FACS analysis. After 11 days of culture, cell increase values were about 7 fold for CD3+, 6 fold for CD3+CD4+, 7 fold for CD3+CD8+, 4fold for CD3+CD56, 6fold for CD56+, and 0.2 fold for CD34+. We characterized the developmental state of these cell populations by RT ĂąâŹâPCR analysis of the lymphoid differentiation markers RAG-1 and pre T-Alpha. In all samples , transcripts of both markers could be detected from day 0 though day 11, however , in case of pre ĂąâŹâ T-Alpha,Ă nested PCRĂ was always required , indicating lower expression . These findings; therefore, demonstrate that T-cell differentiation events (as opposed to mere expansion) do occur in stroma cell free expansion assays
Modeling soil water dynamics considering measurement uncertainty
In shallow water table controlled environments, surface water management impacts groundwater table levels and soil water dynamics. The study goal was to simulate soil water dynamics in response to canal stage raises considering uncertainty in measured soil water content. WAVE (Water and Agrochemicals in the soil, crop and Vadose Environment) was applied to simulate unsaturated flow above a shallow aquifer. Global sensitivity analysis was performed to identify model input factors with greatest influence on predicted soil water content. Nash-Sutcliffe increased and Root Mean Square Error reduced when uncertainties in measured data were considered in goodness-of-fit calculations using measurement probability distributions and probable asymmetric error boundaries; implying that appropriate model performance evaluation should be done using uncertainty ranges instead of single values. Although uncertainty in the experimental measured data limited evaluation of the absolute predictions by the model, WAVE was found a useful exploratory tool for estimating temporal variation in soil water content. Visual analysis of soil water content time series under proposed changes in canal stage management indicated that sites with land surface elevation of less than 2.0 m NGVD29 were predicted to periodically experience saturated conditions in the root zone and shortening of the growing season if canal stage is raised more than 9 cm and maintained at this level. The models developed could be combined with high resolution digital elevation models in future studies to identify areas with the greatest risk of experiencing saturated root zone. The study also highlighted the need to incorporate measurement uncertainty when evaluating performance of unsaturated flow models
Sensitivity analysis and parameter estimation for an approximate analytical model of canal-aquifer interaction applied in the C-111 basin
The goal of this study was to better characterize parameters influencing the exchange of surface water in
south Floridaâs C-111 canal and Biscayne aquifer using the analytical model STWT1. A three-step model evaluation
framework was implemented as follows: (1) qualitative parameter ranking by comparing two Morris method sampling
strategies, (2) quantitative variance-based sensitivity analysis using Sobolâs method, and (3) estimation of parameter
posterior probability distributions and statistics using the Generalized Likelihood Uncertainty Estimator (GLUE)
methodology. Results indicated that the original Morris random sampling method underestimated total parameter effects
compared to the improved global Morris sampling strategy. However, parameter rankings from the two sampling methods
were similar. For the STWT1 model, only four out of the six parameters analyzed were important for predicting water
table response to canal stage and recharge fluctuations. Morris ranking in order of decreasing importance resulted in
specific yield (ASY), aquifer saturated thickness (AB), horizontal hydraulic conductivity (AKX), canal leakance (XAA),
vertical hydraulic conductivity (AKZ), and half-width of canal (XZERO). Sobolâs sensitivity indices for the four most
critical parameters revealed that summation of first-order parameter effects was 1.0, indicating that STWT1 behaved as
an additive model or negligible parameter interactions. We estimated parameter values of 0.07 to 0.14 for ASY, 11,000 to
14,300 m d-1 for AKX, 13.4 to 18.3 m for AB, and 99.8 to 279 m for XAA. The estimated values were within the range of
values estimated using more complex methods at nearby sites. The Nash-Sutcliffe coefficient of efficiency and root mean
square error for estimated parameters ranged from 0.66 to 0.95 and from 4 to 7 cm, respectively. This study demonstrates
a simple and inexpensive way to characterize hydrogeological parameters controlling groundwater-surface interactions in
any region with aquifers that are highly permeable without using standard pumping tests or canal drawdown experiments.
Hydrogeological parameters estimated using this approach could be used as starting values in large-scale numerical
simulations
Dynamic factor analysis of surface water management impacts on soil and bedrock water contents in Southern Florida Lowlands
As part of the C111 spreader canal project, structural and operational modifications involving incremental raises in canal stage are planned along one of the major canals (i.e., C111) separating Everglades National Park and agricultural production areas to the east of the park. This study used Dynamic Factor Analysis (DFA) as an alternative tool to physically based models to explore the relationship between different hydrologic variables and the effect of proposed changes in surface water management on soil and bedrock water contents in south Florida. To achieve the goal, objectives were to: (1) use DFA to identify the most important factors affecting temporal variation in soil and bedrock water contents, (2) develop a simplified DFA based regression model for predicting soil and bedrock water contents as a function of canal stage and (3) assess the effect of the proposed incremental raises in canal stage on soil and bedrock water contents. DFA revealed that 5 common trends were the minimum required to describe unexplained variation in the 11 time series studied. Introducing canal stage, water table evaporation and net recharge resulted in lower Akaike information criterion (AIC) and higher Nash-Sutcliffe (C[subscript eff]) values. Results indicated that canal stage significantly (t > 2) drives temporal variation in soil and bedrock water contents, which was represented as scaled frequency while net surface recharge was significant in 7 out of the 11 time series analyzed. The effect of water table evaporation was not significant at all sites. Results also indicated that the most important factor influencing temporal variation in soil and bedrock water contents in terms of regression coefficient magnitude was canal stage. Based on DFA results, a simple regression model was developed to predict soil and bedrock water contents at various elevations as a function of canal stage and net recharge. The performance of the simple model ranged from good (C[subscript eff] ranging from 0.56 to 0.74) to poor (C[subscript eff] ranging from 0.10 to 0.15), performance was better at sites with smaller depths to water table (< 1 m) highlighting the effect of micro-topography on soil and bedrock water content dynamics. Assessment of the effect of 6, 9 and 12 cm increases in canal stage using the simple regression model indicated that changes in temporal variation in soil and bedrock water contents were negligible (average<1.0% average change) at 500 to 2000 m from C111 (or low elevations) which may be attributed to the near saturation conditions already occurring at these sites. This study used DFA to explore the relationship between soil and bedrock water dynamics and surface water stage in shallow water table environments. This approach can be applied to any system in which detailed physical modeling would be limited by inadequate information on parameters or processes governing the physical system
Lâambiente marino costiero: aspetti e tutela. Progetto formativo di Alternanza Scuola Lavoro 2016â2019 Liceo Scienze Applicate
Il percorso formativo consente di acquisire nozioni teoriche e pratiche sulle moderne tecniche (strumentali e metodologiche) di investigazione del âdatumâ geologico finalizzate allo studio multidisciplinare dellâambiente marinoâcostiero, con particolare riguardo alle ricerche sperimentali che lâIstituto IAMC ha condotto e conduce nel Golfo di Napoli.
Vengono trattate anche tematiche di gestione del sistema sicurezza e qualità con particolare riguardo alle attività lavorative di ricerca (acquisizione, elaborazione e restituzione del dato),nonché indicazioni di procedure gestionali di progetto finalizzate al corretto utilizzo della risorsa umana e strumentale
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