28 research outputs found
Density waves and star formation in grand design spirals
HII regions in the arms of spiral galaxies are indicators of recent
star-forming processes. They may have been caused by the passage of the density
wave or simply created by other means near the arms. The study of these regions
may give us clues to clarifying the controversy over the existence of a
triggering scenario, as proposed in the density wave theory. Using H
direct imaging, we characterize the HII regions from a sample of three grand
design galaxies: NGC5457, NGC628 and NGC6946. Broad band images in R and I were
used to determine the position of the arms. The HII regions found to be
associated with arms were selected for the study. The age and the star
formation rate of these HII regions was obtained using measures on the
H line. The distance between the current position of the selected HII
regions and the position they would have if they had been created in the centre
of the arm is calculated. A parameter, T, which measures whether a region was
created in the arm or in the disc, is defined. With the help of the T parameter
we determine that the majority of regions were formed some time after the
passage of the density wave, with the regions located `behind the arm' (in the
direction of the rotation of the galaxy) the zone they should have occupied had
they been formed in the centre of the arm. The presence of the large number of
regions created after the passage of the arm may be explained by the effect of
the density wave, which helps to create the star-forming regions after its
passage. There is clear evidence of triggering for NGC5457 and a co-rotation
radius is proposed. A more modest triggering seems to exist for NGC628 and non
significant evidence of triggering are found for NGC6946.Comment: 10 pages, 20 figures, accepted for publication in A&
Automatic annotation of bioinformatics workflows with biomedical ontologies
Legacy scientific workflows, and the services within them, often present
scarce and unstructured (i.e. textual) descriptions. This makes it difficult to
find, share and reuse them, thus dramatically reducing their value to the
community. This paper presents an approach to annotating workflows and their
subcomponents with ontology terms, in an attempt to describe these artifacts in
a structured way. Despite a dearth of even textual descriptions, we
automatically annotated 530 myExperiment bioinformatics-related workflows,
including more than 2600 workflow-associated services, with relevant
ontological terms. Quantitative evaluation of the Information Content of these
terms suggests that, in cases where annotation was possible at all, the
annotation quality was comparable to manually curated bioinformatics resources.Comment: 6th International Symposium on Leveraging Applications (ISoLA 2014
conference), 15 pages, 4 figure
Digestibilidad y contenido de factores antinutricionales en el helecho macho (Pteridium aquilinum) y plantas acompañantes en el Chaco hĂșmedo boliviano
Evaluation of iron status in European adolescents through biochemical iron indicators: the HELENA Study
BACKGROUND/OBJECTIVES: To assess the iron status among European adolescents through selected biochemical parameters in a cross-sectional study performed in 10 European cities. SUBJECTS/METHODS: Iron status was defined utilising biochemical indicators. Iron depletion was defined as low serum ferritin (SF8.5 mg/l) plus iron depletion. Iron deficiency anaemia (IDA) was defined as ID with haemoglobin (Hb) below the WHO cutoff for age and sex: 12.0 g/dl for girls and for boys aged 12.5-14.99 years and 13.0 g/dl for boys aged â„15 years. Enzyme linked immunosorbent assay was used as analytical method for SF, sTfR and C-reactive protein (CRP). Subjects with indication of inflammation (CRP >5 mg/l) were excluded from the analyses. A total of 940 adolescents aged 12.5-17.49 years (438 boys and 502 girls) were involved. RESULTS: The percentage of iron depletion was 17.6%, significantly higher in girls (21.0%) compared with boys (13.8%). The overall percentage of ID and IDA was 4.7 and 1.3%, respectively, with no significant differences between boys and girls. A correlation was observed between log (SF) and Hb (r = 0.36, P < 0.01), and between log (sTfR) and mean corpuscular haemoglobin (r = -0.30, P < 0.01). Iron body stores were estimated on the basis of log (sTfR/SF). A higher percentage of negative values of body iron was recorded in girls (16.5%) with respect to boys (8.3%), and body iron values tended to increase with age in boys, whereas the values remained stable in girls. CONCLUSIONS: To ensure adequate iron stores, specific attention should be given to girls at European level to ensure that their dietary intake of iron is adequate.status: publishe
Meningite bacteriana neonatal: estudo prospectivo da evolução a longo prazo de 55 crianças
A simulation of soil water content based on remote sensing in a semi-arid Mediterranean agricultural landscape
This paper shows the application of a water balance based on remote sensing that integrated a Landsat 5 series from 2009 in an area of 1,300 km2 in the Duero Basin (Spain). The objective was to simulate the daily soil water content (SWC), actual evapotranspiration, deep percolation and irrigation rates. The accuracy of the application is tested in a semi-arid Mediterranean agricultural landscape with crops over natural conditions. The results of the simulated SWC were compared against 19 in situ stations of the Soil Moisture Measurement Stations Network (REMEDHUS), in order to check the feasibility and accuracy of the application. The theoretical basis of the application was the FAO56 calculation assisted by remotely sensed imagery. The basal crop coefficient (Kcb), as well as other parameters of the calculation came from the remote reflectance of the images. This approach was implemented in the computerized tool HIDROMORE+, which integrates various spatial databases. The comparison of simulated and observed values (at different depths and different land uses) showed a good global agreement for the area (R2=0.92, RMSE=0.031 m3 m-3, and bias=-0.027 m3 m-3). The land uses better described were rainfed cereals (R2=0.86, RMSE=0.030 m3 m-3, and bias=-0.025 m3 m-3) and vineyards (R2=0.86, RMSE=0.016 m3 m-3, and bias=-0.013 m3 m-3). In general, an underestimation of the soil water content is noticed, more pronounced into the root zone than at surface layer. The final aim was to convert the application into a hydrological tool available for agricultural water management
Assessing the capability of the SWAT model to simulate snow, snow melt and streamflow dynamics over an alpine watershed
Analysis of bone demineralization due to the use of exoprosthesis by comparing Youngâs Modulus of the femur in unilateral transfemoral amputees
3596230993
Thin-walled composite aircraft structures commonly used on fuselage and wing skins are prone to in-service impacts that could compromise the structural integrity and could be hard and expensive to detect by traditional methods. The development of a Structural Health Monitoring (SHM) System able to detect and characterize this kind of impacts can reduce the cost for maintenance and inspection and furthermore the results obtained from this system could be used to improve the analysis and design of the structure. However, one of the main challenges of a SHM system is the detection and location of impacts as well as the characterization of the resulting damages. A SHM system based on the detection of the elastic waves generated by an impact has been developed by Airbus Defence and Space In order to increase the knowledge of the structural response under impact, a set of Numerical Simulations using Explicit Finite Element analysis codes have been performed: These simulations cover different typical aircraft structures and they have been validated against physical tests; however the correlation between simulations and tests present some complexity due to its sensibility to a great number of undetermined factors, the difficulties of wave characterization and the determination of wave times of arrival to a specific location. Due to that complexity, a surrogate modelling optimization process, developed with our partner Mathlas, has been introduced in order to improve the correlation between test and analysis. The target of this study is to develop a robust simulation methodology which could support the development of a reliable Structural Health Monitoring System for real aircraft structures reducing the number of physical tests and improving the methodologies for FEM-Test correlation. The paper presents details of the different FE Models and test specimens, results from simulation and tests and highlights the advantages and challenges of this simulation and correlation methodology
Prepotent response inhibition and reaction times in children with attention deficit/hyperactivity disorder from a Caribbean community
Abstract Impairment in inhibitory control has been postulated
as an underlying hallmark of attention deficit/hyperactivity
disorder (ADHD), which can be utilized as a
quantitative trait for genetic studies. Here, we evaluate
whether inhibitory control, measured by simple automatized
prepotent response (PR) inhibition variables, is a
robust discriminant function for the diagnosis of ADHD in
children and can be used as an endophenotype for future
genetic studies. One hundred fifty-two school children
(30.9% female, 67.8% with ADHD) were recruited. The
ADHD checklist was used as the screening tool, whilst the
DSM-IV Mini International Neuropsychiatry Interview,
neurologic interview and neurologic examination, and the
WISC III FSIQ test were administered as the gold standard
procedure to assert ADHD diagnosis. A Go/No-Go task
using a naturalistic and automatized visual signal was
administered. A linear multifactor model (MANOVA) was
fitted to compare groups including ADHD status, age, and
gender as multiple independent factors. Linear discriminant
analysis and the receiver operating characteristic curve
were used to assess the predictive performance of PR
inhibition variables for ADHD diagnosis. We found that
four variables of prepotent response reaction time- and
prepotent response inhibition established statistically significant
differences between children with and without
ADHD. Furthermore, these variables generated a strong
discriminant function with a total classification capability
of 73, 84% specificity, 68% sensitivity, and 90% positive
predictive value for ADHD diagnosis, which support
reaction times as a candidate endophenotype that could
potentially be used in future ADHD genetic research