1,462 research outputs found
Relativistic correlation correction to the binding energies of the ground configuration of Beryllium-like, Neon-like, Magnesium-like and Argon-like ions
Total electronic correlation correction to the binding energies of the
isoelectronic series of Beryllium, Neon, Magnesium and Argon, are calculated in
the framework of relativistic multiconfiguration Dirac-Fock method. Convergence
of the correlation energies is studied as the active set of orbitals is
increased. The Breit interaction is treated fully self-consistently. The final
results can be used in the accurately determination of atomic masses from
highly charged ions data obtained in Penning-trap experiments.Comment: version soumise 3/08/200
Pre-school science education in Portugal: teacher education and innovative practices
Assuming science education in the early years as the stepping stone for the development of scientific and technological literacy, a teacher training program was developed with six kindergarten teachers in Portugal. Its aim was to promote the (re)construction of their subject content and pedagogical knowledge leading to innovative practices, based on the characterization of their profile, shortcomings and practices.
Learning through practice was considered the most effective means to promote change in kindergarten teachersâ curricular approaches to science, hence the development of practical activities focusing on childrenâs understanding and requiring their scientific knowledge and enquiry processes.
These include a teacherâs guide (presenting its objectives, concepts and teaching, learning and assessment strategies), a theoretical framework (presenting the concepts, known misconceptions and research references) and also the necessary didactic resources.
The paper details the results of the developed teacher training program as well of the validation process of the designed teaching strategies
Interannual sub-aerial beach variability along a sector of the TrĂłia- Sines embayed coast
The comprehension of sub-aerial beach variability of sandy beaches is essential to describe and predict his behaviour after
extreme events (e.g. storms). Around the world coastline beach monitoring plans are established in order to characterize the
main morphodynamic changes at different spatial and temporal scales. Within this scope, four field surveys (19th to 28th May
2009; 30th October to 10th November 2009, 21th to 30th May 2010 and 14l to 21 April 2011), using a new coastal survey
system named INSHORE system(Differential Global Positioning System) [1], were conducted along the TrĂłia-Sines
embayed beach (INSHORE project -PTDC/AMB/73169/2006).
The interannual variability of the sub-aerial beach topography along the TrĂłia-Sines embayed coast for the first three field
surveys were analysed considering the DEM (Digital Elevation Model) analysis regarding the: alongshore coastline
configuration; subaerial beach width; beach profile configuration and volumetric changes.
The results points to the definition of eight main coastline sectors very similar to the results previously described by [2].
Although a general north-south increasing beach width trend can be observed, [3] one of these main sectors, Sector 6,
presents a significant variation of the beach width and beach profile configuration. This sector was selected to describe the
morphodynamic pattern responsible for the sediment accommodation (beach width, and profile configuration) during the
studied period.
The subtraction between the three DEMs points to the importance of the beach width variation that describes the landward
or seaward subaerial beach displacement. Although this might affect the beach width, this variable should not be taken as
the unique one to describe the shoreline change. In fact, this parameter does not describe the beach variability regarding
the profile configuration (e.g. berm width and sediment accommodation). According to our results the volumetric changes
are strictly related to the beach width variation but the profile configuration has a particular role in the final budget analysis.
The proxies that were used (+2m, +3.4m and +4,3m MSL elevation contours) and the relation between the beach width and
subaerial beach volume, has given high correlation values. These results proved that not only the MHW (mean high water)
used by others authors [4] can be defined as a proxy to describe the shoreline evolution, but also other morphodynamic
meaningful contour elevations can give reliable results
Effects of sportswear design on thermal comfort
ISBN 978-2-7466-2858-8Several technical developments in the sportswear clothing industry resulted in the use of functional textiles for highly-specialized performances in all kind of sports.
This paper reports on an experimental investigation on the effects of garment design in thermo-physiological body comfort, measured in terms of clothing insulation for a specific outdoor sport - rowing.
The thermal manikins have been used to measure clothing insulation and to evaluate the thermal comfort. Thermal manikins provide a good estimate of the total dry heat loss from the body and the distribution of heat flow over the body surface. In a standard environment, these measurements can be used to describe the thermal characteristics of clothing.
Testing of sportswear clothing made of different fibers and garment designs, namely by varying knitting structures, show the possibilities of influencing thermal comfort, especially thermal insulation.
The evaluation and understanding of the thermal effects of garment design and fabric materials is important for the development and optimization of functional garments.
Therefore, the final aim of this paper is to study and validate the thermal comfort behaviour of active sportswear for rowing using single and multiple knitted zones in the garment design and considering also differences in material composition through thermal manikin measurements
Content in metallic ions of wines from the Madeira and Azores archipelagos
This study determines for the first time Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb contents in wines from the archipelagos of Madeira and Azores (Portugal). The greater part of the mean content for the different parameters fell within the ranges described in the literature, except for sodium whose higher content may be due to the effect of marine spray. ANOVA was used to establish the metals with significant differences in mean content between the wines from both archipelagos, between table and liquor wines of Madeira, and between wines of Pico and Terceira Islands from the Azores archipelago. Principal component analysis shows differences in the wines according to the wine-making process and/or the equipment employed. Stepwise linear discriminant analysis achieves a good classification and validation of wines according to the archipelago of origin, and the island in the case of Azores wines
Integration and embedding of vital signs sensors and other devices into textiles
The development of ubiquitous vital sign monitoring has become a very up-to-date research theme for many academics and industrial companies in the last years. With new materials and integration techniques, it is possible to implement vital sign monitoring in an economic manner, directly into textile products. This unobtrusive presence of sensors is especially important for the monitoring of children or elderly people. This paper focuses on two aspects of sensor integration: Integration of off-the-shelf electronic components, and the use of the textile material itself as sensor, or in general as an electrically active element presenting some exploratory work in the integration of electronic devices into textiles. The main objective was to reproduce and improve on previous work presented by other authors, and foster possibilities of developing garments for vital sign monitoring with immediate industrial and economic feasibility. The use of standard production techniques to produce textile-based sensors, easily integrated into garments and with mass-market potential, is one of the important motivations for this work
High spatio-temporal resolution in functional MRI with 3D echo planar imaging using cylindrical excitation and a CAIPIRINHA undersampling pattern
Purpose
The combination of 3D echo planar imaging (3DâEPI) with a 2DâCAIPIRINHA undersampling scheme provides high flexibility in the optimization for spatial or temporal resolution. This flexibility can be increased further with the addition of a cylindrical excitation pulse, which exclusively excites the brain regions of interest. Here, 3DâEPI was combined with a 2D radiofrequency pulse to reduce the brain area from which signal is generated, and hence, allowing either reduction of the field of view or reduction of parallel imaging noise amplification.
Methods
3DâEPI with cylindrical excitation and 4âĂâ3âfold undersampling in a 2DâCAIPIRINHA sampling scheme was used to generate functional MRI (fMRI) data with either 2âmm or 0.9âmm inâplane resolution and 1.1âs temporal resolution over a 5âcm diameter cylinder placed over both temporal lobes for an auditory fMRI experiment.
Results
Significant increases in image signalâtoânoise ratio (SNR) and temporal SNR (tSNR) were found for both 2âmm isotropic data and the highâresolution protocol when using the cylindrical excitation pulse. Both protocols yielded highly significant blood oxygenation levelâdependent responses for the presentation of natural sounds.
Conclusion
The higher tSNR of the cylindrical excitation 3DâEPI data makes this sequence an ideal choice for high spatiotemporal resolution fMRI acquisitions. Magn Reson Med 79:2589â2596, 2018. © 2017 International Society for Magnetic Resonance in Medicine
Educational needs in people with ankylosing spondylitis and psoriatic arthritis: A cross-sectional study
Objective: To assess the educational needs of people with Ankylosing Spondylitis (AS) and Psoriatic Arthritis (PsA), test differences across patient subgroups and identify factors independently associated with their educational needs.Methods: This was a cross-sectional analytic study. Patients with AS and PsA completed the Portuguese version of the Educational Needs Assessment Tool (PortENAT). Data were Rasch-transformed before descriptive and inferential analyses were undertaken. Univariable and multivariable analyses were used to determine differences between patient subgroups and factors independently associated with their educational needs.Results: The study included 121 patients with AS and 132 with PsA. The level of educational needs varied by diagnostic group, but higher needs for both subgroups were reported regarding the âDisease processâ, âFeelingsâ and âManaging painâ domains. Overall, patients with AS had a higher level of educational needs than those with PsA. In both disease groups, female gender was independently associated with higher educational needs. In the PsA group, a shorter disease duration was independently associated with higher educational needs in the following domains: âManaging painâ, âMovementâ and âFeelingsâ.Conclusion: Educational needs vary by diagnostic group, gender and disease duration. These differences merit consideration in the design of patient education interventions
Single-shot frequency offset measurement with HASTE using the selective parity approach
Measurements of frequency offset are commonly required in MRI. The standard method measures the signal phase as a function of evolution time. Here we use a single shot turbo-spin-echo acquisition method to measure frequency offset at a single evolution time. After excitation the transverse magnetisation evolves during the evolution time, and is then repeatedly refocused. The phase is conjugated between alternate echoes. Using partial parallel acquisition techniques we obtain separate odd- and even- echo images. An iterative procedure ensures self-consistency between them. The difference in phase between the two images yields frequency offset maps. The technique was implemented at 3 Tesla and tested on a healthy human volunteer for a range of evolution times between 6 and 42Â ms. A standard method using a similar readout train and multiple evolution times was used as a gold-standard measure. In a statistical comparison with the gold standard no evidence for bias or offset was found. There was no systematic variation in precision or accuracy as a function of evolution time. We conclude that the presented approach represents a viable method for the rapid generation of frequency offset maps with a high image quality and minimal distortion.</p
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