1,175 research outputs found
Standardized experimental estimation of the maximum unnoticeable environmental displacement during eye blinks for redirect walking in virtual reality
Redirect walking is a technique that aims to manipulate the walking trajectories in immersive virtual reality settings by inducing unnoticeable displacements of the virtual environment. Taking into advantage the change blindness phenomenon, visual occlusion during eye blinks has been recently proposed to perform those displacements. This study determined the maximum unnoticeable displacement that can be performed in practical scenario, which proved to be near 0.8° of occlusion and disocclusion in both horizontal and vertical axes
Generation of a toponimics geodatabase for Andalusia in the andalusian institute of cartography (Southern Spain)
Generating a place-name database is a difficult task. This communication describes the process used to generate a database for toponimics in Andalusia. The source has been an ARC/INFO GIS cartographic data model with 2,745 cartographic sheets at a 1:10,000 scale. We transformed this information into a place-names database with a few macros and a large number of non-automated processes. Furthermore, the Geographic Information Systems helped us to revise errors and in the final design of the geodatabase. The result is a geodatabase with more than 190,000 geo-referenced entries. These entries are going to be the core of the Andalusian Geographic Nomenclature – the next new ICA project
Re-Naturing Cities: evaluating the effects on future air quality in the city of Porto
The effect of different “green” measures, such as the increase of urban green areas, the application of green roofs and the increase of surfaces albedo on urban air quality were evaluated with the WRF-CHIMERE modelling system. In order to account for the heterogeneity of urban areas, a single layer urban canopy model was coupled to the WRF model. The case study consists of a heat wave occurring in the Porto (Portugal) urban area in a future climate scenario, considering the Representative Concentration Pathway RCP8.5. The influence of the selected measures on PM10, NO2 and O3 concentrations was quantified and compared with a control run (without measures) simulation scenario. The results revealed that all the measures are able to mitigate the effects of heat waves by reducing the air temperature between −0.5 °C and −1 °C (maximum differences for the mean of the episode). Positive and negative effects were found in terms of air quality. The implementation of green roofs and the increase of surfaces albedo promoted an overall increase of PM10 (between +0.6% and +1.5%) and NO2 (between +0.8% and 3.5%) concentrations, which are closely related to a decrease of vertical mixing in the urban boundary layer. The increase of green urban areas promoted an overall decrease (on average) of both PM10 and NO2, by around −1% and −3%, respectively. The O3 levels increased with the increase of urban green areas, mostly located over the Porto urban area. Slight differences were promoted by the implementation of green roofs. For the increase of surfaces albedo, both increases and decreases of O3 concentrations were observed. The obtained results contribute to the knowledge of the chemical composition of the urban atmosphere and can be of great importance for stakeholders and decision-makers to deal with climate change impacts.publishe
Fatigue behaviour of laser repairing welded joints
This paper presents a fatigue study in Nd-YAG laser surface repairing welded joints in specimens of two base materials used in mould production. The tests were carried out in a servo-hydraulic machine in tension, under constant amplitude loading, with two stress ratios R = 0 and R = 0.4. Welded specimens were prepared with U notches and filled with laser welding deposits. The fatigue results are presented in the form of S-N curves obtained in welded and non-welded conditions. Complementary measurements of hardness and residual stresses profiles were carried out along the surface of laser welded specimens to understand the observed fatigue behaviour. The melted material was the weaker region, with lower values of hardness and higher tensile residual stresses, presenting also a high number of defects that are potential failure sites. The presence of such defects can explain the relatively poor fatigue strength of the laser repairing joints in comparison to base materials.http://www.sciencedirect.com/science/article/B6V2X-4N2M6PH-1/1/945a7f442fb922704c73d665abcb0b0
Mould steels repaired by laser welding
Laser-deposit welding, by using Nd-YAG, is a mould repairing process, which has the advantages relatively to the traditional methods of achieving a less change of the metal composition around the repaired zone and permitting a very accurate deposition of a small volume of the filler material in the area chosen at the work-piece surface. This paper presents a fatigue study in specimens of two base materials used in mould production (AISI H13 and P20). Filler material as well as welding parameters were analysed in order to obtain better fatigue strength. The tests were carried out under constant amplitude loading, with two stress ratios R = 0 and R = 0.4. Welded specimens were prepared with V notches and filled with laser welding deposits. The fatigue results are presented in the form of S-N curves obtained in welded and non-welded conditions. Complementary measurements of hardness profiles and SEM analysis were carried out to understanding the fatigue behaviour and failure sites. The laser-deposit material was the weaker region in both steels, due to a high level of tensile residual stresses and also to some planar defects that are potential failure sites. Fatigue crack initiation is therefore reduced and the fatigue propagation life is enhanced. A significant mean stress effect in the base material was also observed in both mould steels.http://www.sciencedirect.com/science/article/B6V2X-4S03RKY-3/1/b8b7da232b765381e7d08d9f3d7f897
Método para la detección, identificación y cuantificación de Peronospora arborescens por PCR cuantitativa en tiempo real
Método para la detección, identificación y cuantificación
de Peronospora arborescens por PCR cuantitativa en
tiempo real.
El método para la cuantificación de Peronospora arborescens
por PCR cuantitativa (qPCR) en una muestra biológica,
comprende extraer el ADN contenido en dicha muestra
biológica y amplificarlo mediante qPCR. De aplicación
en la cuantificación de P. arborescens.Peer reviewedConsejo Superior de Investigaciones Científicas (España), ALCALIBER SA, Universidad de CórdobaA1 Solicitud de patentes con informe sobre el estado de la técnic
Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants
Two haplotypes of Xylella fastidiosa subsp. pauca (Xfp) that correlated with their host of origin were identified in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the gyrB sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of Xfp according to the host source. The protocol proved to be robust for the prediction of the Xfp host source in blind tests using DNA from cultures of the bacterium, infected plants, and insect vectors allowed to feed on Xfp-infected citrus plants. AMOVA and STRUCTURE analyses of microsatellite data separated most Xfp populations on the basis of their host source, indicating that they were genetically distinct. The combined use of the SNaPshot protocol and three previously developed multilocus SSR markers showed that two haplotypes and distinct isolates of Xfp infect citrus and coffee in Brazil and that multiple, genetically different isolates can be present in a single orchard or infect a single tree. This combined approach will be very useful in studies of the epidemiology of Xfp-induced diseases, host specificity of bacterial genotypes, the occurrence of Xfp host jumping, vector feeding habits, etc., in economically important cultivated plants or weed host reservoirs of Xfp in Brazil and elsewhere [Int Microbiol 2015; 18(1):13-24]Keywords: Citrus variegated chlorosis · coffee leaf scorch · vector transmission· xylem-limited bacteria · haplotype characterization · host-plant associatio
Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants
Two haplotypes of
Xylella fastidiosa
subsp.
pauca
(Xfp) that correlated with their host of origin were identified
in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the
gyrB
sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of
Xfp
according
to the host source. The protocol proved to be robust for the prediction of the
Xfp
host source in blind tests using DNA from
cultures of the bacterium, infected plants, and insect vectors allowed to feed on
Xfp-
infected citrus plants. AMOVA and
STRUCTURE analyses of microsatellite data separated most
Xfp
populations on the basis of their host source, indicating that
they were genetically distinct. The combined use of the SNaPshot protocol and three previously developed multilocus SSR
markers showed that two haplotypes and distinct isolates of
Xfp
infect citrus and coffee in Brazil and that multiple, genetically
different isolates can be present in a single orchard or infect a single tree. This combined approach will be very useful in studies
of the epidemiology of
Xfp-
induced diseases, host specificity of bacterial genotypes, the occurrence of
Xfp
host jumping, vector
feeding habits, etc., in economically important cultivated plants or weed host reservoirs of
Xfp
in Brazil and elsewhere
[Int Microbiol 2015; 18(1):13-24].We acknowledge financial support from the EU grant ICA4-CT-2001-10005 and an ‘Intramural Project’ to B. B. Landa from the Spanish National Research Council (CSIC), as well as CNPq for a scholarship to J. R. S. Lopes in Brazil.Peer reviewe
The molar extinction coefficient of bacteriochlorophyll e and the pigment stoichiometry in Chlorobium phaeobacteroides
We have determined the molar extinction coefficient of bacteriochlorophyll (BChl) e, the main light-harvesting pigment from brown-coloured photosynthetic sulfur bacteria. The extinction coefficient was determined using pure[Pr,E]BChl eF isolated by reversed-phase HPLC from crude pigment extracts of Chlorobium (Chl.) phaeobacteroides strain CL1401. The extinction coefficients at the Soret and Qy bands were determined in four organic solvents. The extinction coefficient of BChl e differs from those of other related Chlorobium chlorophylls (BChl
c and BChl d) but is similar to that of chlorophyll b. The determined extinction coefficient was used to calculate the stoichiometric BChl e to BChl a and BChl e to carotenoids ratios in whole cells and isolated chlorosomes from Chl. phaeobacteroides strain CL1401 using the spectrum-reconstruction method (SRCM) described by Naqvi et al. (1997) (Spectrochim Acta A Mol Biomol Spectrosc 53: 2229–2234). In isolated chlorosomes, BChl a content was ca. 1% of the total BChl content and the stoichiometric ratio of BChl e to carotenoids was 6. In whole cells,however, BChl a content was 3–4%, owing to the presence of BChl a-containing elements, i.e. FMO protein and reaction centre. An average of 5 BChl e molecules per carotenoid was determined in whole cells.EU(Contract No FMRX–CT96–0081). Ministerio de Educación y Ciencia (Ref. BIO96–1229–002–01)Peer reviewe
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