560 research outputs found
Global visualization and quantification of compressible vortex loops
The physics of compressible vortex loops generated due to the rolling up of the shear layer upon the diffraction of a shock wave from a shock tube is far from being understood, especially when shock-vortex interactions are involved. This is mainly due to the lack of global quantitative data available which characterizes the flow. The present study involves the usage of the PIV technique to characterize the velocity and vorticity of compressible vortex loops formed at incident shock Mach numbers ofM=1.54 and1.66. Another perk of the PIV technique over purely qualitative methods, which has been demonstrated in the current study, is that at the same time the results also provide a clear image of the various flow features. Techniques such as schlieren and shadowgraph rely on density gradients present in the flow and fail to capture regions of the flow influenced by the primary flow structure which would have relatively lower pressure and density. Various vortex loops, namely, square, elliptic and circular, were generated using different shape adaptors fitted to the end of the shock tube. The formation of a coaxial vortex loop with opposite circulation along with the generation of a third stronger vortex loop ahead of the primary with same circulation direction are of the interesting findings of the current study
Concentration of fecal coliforms in marine waters using satellite images in the vicinity of Pucusana. Bay, Peru.
Water quality monitoring in coastal areas is challenging due to cost and time constraints. Identifying and selecting sampling sites accurately and effectively is crucial for efficient monitoring. The need for efficient monitoring of marine waters has led to exploring the use of remote sensing as one helpful alternative. Remote sensing is practical in several applications based on pattern recognition and information processing of large terrestrial and aquatic surface areas. Collected information is processed with various image processing techniques to identify objects such as microorganisms. Fecal coliforms are microorganisms that are indicators of sanitary quality and are present in human and animal wastes discharged into water bodies reaching coastal regions. The present study estimated the presence of fecal coliforms as an indicator of contamination in coastal marine waters. Satellite data from two sensors, Landsat 7 ETM+ and Landsat 8 OLI, were used to evaluate the reflectance of fecal coliforms in marine waters. Then, statistical analysis and four regression models were tested to establish a functional correlation between the spectral bands and historical in situ fecal coliform measurement. In this research, satellite imagery in the vicinity of Pucusana Bay helped estimate the concentration of fecal coliforms in marine waters. As a result, a significant relationship was found between the shortwave infrared band splitting (SWIR 2) with the blue band and fecal coliforms presence. The relationship was used to estimate coliform concentration from the reflectance of the aquatic surface in Pucusana Bay. Finally, spatial distribution maps of fecal coliform concentrations were generated to compare the increase of these microorganisms over different years in the area. The methodology and results can be calibrated to other water body locations where fecal coliform is a concern
Evolution of endogenous retroviruses in the Suidae: evidence for different viral subpopulations in African and Eurasian host species
Influencia de la autoeficacia hacia la actividad física sobre el envejecimiento activo
La Organización Mundial de la Salud (2002) reconoce la práctica de la actividad física como un determinante del envejecimiento activo exitoso, y declara que los adultos mayores físicamente activos presentan una mayor salud funcional y menor riesgo de limitaciones funcionales moderadas o graves. Sin embargo, las estrategias para cambiar los estilos de vida sedentarios por estilos de vida activos son menos evidentes. El presente trabajo evaluó la autoeficacia hacia la actividad física y analizó su relación con los niveles de actividad física y condición física, así como con la independencia funcional y calidad de vida en un grupo de adultos mayores del estado de Yucatán, México. La muestra fue de 55 participantes con deambulación conservada y sin deteriroro cognitivo, a los cuales se les aplicó una batería de cinco pruebas. Como resultado de los análisis, la autoeficacia demostró estar relacionada con los niveles de actividad física y condición física, los cuales predijeron la independencia funcional y calidad de vida. En este sentido, la mejora en la autoeficacia se convierte en una herramienta valiosa y necesaria si se desea fomentar la motivación y la autoconfianza hacia la práctica de actividad física, así como un elemento fundamental para el envejecimiento activo
Fundamental and high-order anapoles in all-dielectric metamaterials via Fano-Feshbach modes competition
One of the most fascinating possibilities enabled by metamaterials is the strong reduction of the electromagnetic scattering from nanostructures. In dielectric nanoparticles, the formation of a minimal scattering state at specific wavelengths is associated with the excitation of photonic anapoles, which represent a peculiar type of radiationless state and whose existence has been demonstrated experimentally. In this work, we investigate the formation of anapole states in generic dielectric structures by applying a Fano–Feshbach projection scheme, a general technique widely used in the study of quantum mechanical open systems. By expressing the total scattering from the structure in terms of an orthogonal set of internal and external modes, defined in the interior and in the exterior of the dielectric structure, respectively, we show how anapole states are the result of a complex interaction among the resonances of the system and the surrounding environment. We apply our approach to a circular resonator, where we observe the formation of higher-order anapole states, which are originated by the superposition of several internal resonances of the system
Lidar and Deep Learning Reveal Forest Structural Controls on Snowpack
Forest structure has a strong relationship with abiotic components of the environment. For example, canopy morphology controls snow depth through interception and modifies incoming thermal radiation. In turn, snow water availability affects forest growth, carbon sequestration, and nutrient cycling. We investigated how structural diversity and topography affect snow depth patterns across scales. The study site, Grand Mesa, Colorado, is representative of many areas worldwide where declining snowpack and its consequences for forest ecosystems are increasingly an environmental concern. On the basis of a convolution neural network model (R2 of 0.64; root mean squared error of 0.13 m), we found that forest structural and topographic metrics from airborne light detection and ranging (lidar) at fine scales significantly influence snow depth during the accumulation season. Moreover, complex vertically arranged foliage intercepts more snow and results in shallower snow depths below the canopy. Assessing forest structural controls on snow distribution and depth will aid efforts to improve understanding of the ecological and hydrological impacts of changing snow patterns
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Effectiveness and safety of mechanical thrombectomy for acute ischaemic stroke in Latin American countries: A systematic review
YesTo describe the use, effectiveness, and safety outcomes of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) in Latin American countries.
Studies reporting MT outcomes for AIS in Latin America were identified in CINAHL, MEDLINE, Web of Science, SciELO, EMBASE, and LILACS databases. Synthesis was conducted according to effectiveness (recanalization rates) and safety measures (mortality and functional independence at 90 days).
Seventeen studies were included, mainly from public and university hospitals. MT utilization varied from 2.6% to 50.1%, while successful recanalization ranged from 63% to 95%. Functional independence 90 days after stroke (a modified Rankin scale score of 0 to 2) was achieved in less than 40% across most studies. Mortality rates were below 30%; studies with posterior circulation strokes reported higher mortality rates. The randomized trial reported better health outcomes for functional independence among patients in the MT group (OR 2.28; 95% CI, 1.41 - 3.69), favoring MT over standard care.
The included studies had great methodological heterogeneity due to differences in study design, the MT time window, and stroke location. The only randomized trial showed improved functional independence and lower mortality rates with MT than with standard care. The rest of the studies reported similar findings to available literature. Efforts to improve stroke care are reflected in improved patient outcomes in the region. Future studies should consider standard time window criteria and reduce the risk of bias by including representative samples and comparison groups
PhosphoregDB: The tissue and sub-cellular distribution of mammalian protein kinases and phosphatases
BACKGROUND: Protein kinases and protein phosphatases are the fundamental components of phosphorylation dependent protein regulatory systems. We have created a database for the protein kinase-like and phosphatase-like loci of mouse that integrates protein sequence, interaction, classification and pathway information with the results of a systematic screen of their sub-cellular localization and tissue specific expression data mined from the GNF tissue atlas of mouse. RESULTS: The database lets users query where a specific kinase or phosphatase is expressed at both the tissue and sub-cellular levels. Similarly the interface allows the user to query by tissue, pathway or sub-cellular localization, to reveal which components are co-expressed or co-localized. A review of their expression reveals 30% of these components are detected in all tissues tested while 70% show some level of tissue restriction. Hierarchical clustering of the expression data reveals that expression of these genes can be used to separate the samples into tissues of related lineage, including 3 larger clusters of nervous tissue, developing embryo and cells of the immune system. By overlaying the expression, sub-cellular localization and classification data we examine correlations between class, specificity and tissue restriction and show that tyrosine kinases are more generally expressed in fewer tissues than serine/threonine kinases. CONCLUSION: Together these data demonstrate that cell type specific systems exist to regulate protein phosphorylation and that for accurate modelling and for determination of enzyme substrate relationships the co-location of components needs to be considered
Global distribution and diversity of ovine-associated Staphylococcus aureus
Staphylococcus aureus is an important pathogen of many species, including sheep, and impacts on both human and animal health, animal welfare, and farm productivity. Here we present the widest global diversity study of ovine-associated S. aureus to date. We analysed 97 S. aureus isolates from sheep and sheep products from the UK, Turkey, France, Norway, Australia, Canada and the USA using multilocus sequence typing (MLST) and spa typing. These were compared with 196 sheep isolates from Europe (n = 153), Africa (n = 28), South America (n = 14) and Australia (n = 1); 172 bovine, 68 caprine and 433 human S. aureus profiles. Overall there were 59 STs and 87 spa types in the 293 ovine isolates; in the 97 new ovine isolates there were 22 STs and 37 spa types, including three novel MLST alleles, four novel STs and eight novel spa types. Three main CCs (CC133, CC522 and CC700) were detected in sheep and these contained 61% of all isolates. Four spa types (t002, t1534, t2678 and t3576) contained 31% of all isolates and were associated with CC5, CC522, CC133 and CC522 respectively. spa types were consistent with MLST CCs, only one spa type (t1403) was present in multiple CCs. The three main ovine CCs have different but overlapping patterns of geographical dissemination that appear to match the location and timing of sheep domestication and selection for meat and wool production. CC133, CC522 and CC700 remained ovine-associated following the inclusion of additional host species. Ovine isolates clustered separately from human and bovine isolates and those from sheep cheeses, but closely with caprine isolates. As with cattle isolates, patterns of clonal diversification of sheep isolates differ from humans, indicative of their relatively recent host-jump
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