139 research outputs found
Transmission properties of a single metallic slit: From the subwavelength regime to the geometrical-optics limit
In this work we explore the transmission properties of a single slit in a
metallic screen. We analyze the dependence of these properties on both slit
width and angle of incident radiation. We study in detail the crossover between
the subwavelength regime and the geometrical-optics limit. In the subwavelength
regime, resonant transmission linked to the excitation of waveguide resonances
is analyzed. Linewidth of these resonances and their associated electric field
intensities are controlled by just the width of the slit. More complex
transmission spectra appear when the wavelength of light is comparable to the
slit width. Rapid oscillations associated to the emergence of different
propagating modes inside the slit are the main features appearing in this
regime.Comment: Accepted for publication in Phys. Rev.
Validation of a CFD model by using 3D sonic anemometers to analyse the air velocity generated by an air-assisted sprayer equipped with two axial fans
A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values
Effect of an educational intervention in primary care physicians on the compliance of indicators of good clinical practice in the treatment of type 2 diabetes mellitus [OBTEDIGA project]
[Abstract] Aim. To evaluate the effect of an educational intervention among primary care physicians on several indicators of good clinical practice in diabetes care.
Methods. Two groups of physicians were randomly assigned to the intervention or control group (IG and CG). Every physician randomly selected two samples of patients from all type 2 diabetic patients aged 40 years and above and diagnosed more than a year ago. Baseline and final information were collected cross-sectionally 12 months apart, in two independent samples of 30 patients per physician. The educational intervention comprised: distribution of educational materials and physicians' specific bench-marking information, an on-line course and three on-site educational workshops on diabetes. External observers collected information directly from the physicians and from the medical records of the patients on personal and family history of disease and on the evolution and treatment of their disease. Baseline information was collected retrospectively in the control group.
Results. Intervention group comprised 53 physicians who included a total of 3018 patients in the baseline and final evaluations. CG comprised 50 physicians who included 2868 patients in the same evaluations. Measurement of micro-albuminuria in the last 12 months (OR = 1.6, 95% CI: 1.1–2.4) and foot examination in the last year (OR = 2.0, 95% CI: 1.1–3.6) were the indicators for which greater improvement was found in the IG. No other indicator considered showed statistically significant improvement between groups.
Conclusions. The identification of indicators with very low level of compliance and the implementation of a simple intervention in physicians to correct them is effective in improving the quality of care of diabetic patients
Tracing the retina to analyze the integrity and phagocytic capacity of the retinal pigment epithelium
We have developed a new technique to study the integrity, morphology and functionality of the retinal neurons and the retinal pigment epithelium (RPE). Young and old control albino (Sprague-Dawley) and pigmented (Piebald Virol Glaxo) rats, and dystrophic albino (P23H-1) and pigmented (Royal College of Surgeons) rats received a single intravitreal injection of 3% Fluorogold (FG) and their retinas were analyzed from 5 minutes to 30 days later. Retinas were imaged in vivo with SD-OCT and ex vivo in flat-mounts and in cross-sections. Fifteen minutes and 24 hours after intravitreal administration of FG retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer reached the RPE 15 minutes after FG administration, and this labeling remained up to 30 days. Tracing for 15 minutes or 24 hours did not cause oxidative stress. Intraretinal tracing delineated the pathological retinal remodelling occurring in the dystrophic strains. The RPE of the P23H-1 strain was highly altered in aged animals, while the RPE of the RCS strain, which is unable to phagocytose, did not accumulate the tracer even at young ages when the retinal neural circuit is still preserved. In both dystrophic strains, the RPE cells were pleomorphic and polymegathic
Light-Harvesting Properties of a Subphthalocyanine Solar Absorber Coupled to an Optical Cavity
Optical forces on cylinders near subwavelength slits illuminated by a photonic nanojet
We discuss optical forces exerted on particles, either dielectric or
metallic, near a subwavelength slit illuminated by a photonic nanojet. We
compare those cases in which the Mie resonances are or are not excited. The
configurations on study are 2D, hence those particles are infinite cylinders
and, in order to obtain extraordinary transmission, the illuminating beam is
p-polarized. We show the different effects of these particle resonances on the
optical forces: while whispering gallery modes under those illumination
conditions weaken the force strength, this latter is enhanced by localized
plasmon excitation. Also, illuminating the slit with a nanojet enhances the
optical forces on the particle at the exit of the aperture by a factor between
3 and 10 compared with illumination of the slit with a Gausian beam. In
addition, the pulling force that such a small resonant metallic particle
suffers on direct illumination by a nanojet, can change by the presence of the
slit, so that it may become repulsive at certain lateral positions of the
particle
Molecular-orbital theory for the stopping power of atoms in the low velocity regime:the case of helium in alkali metals
A free-parameter linear-combination-of-atomic-orbitals approach is presented
for analyzing the stopping power of slow ions moving in a metal. The method is
applied to the case of He moving in alkali metals. Mean stopping powers for He
present a good agreement with local-density-approximation calculations. Our
results show important variations in the stopping power of channeled atoms with
respect to their mean values.Comment: LATEX, 3 PostScript Figures attached. Total size 0.54
Dynamics of the population of Common quail males in the island of Majorca and comparison with the northeast peninsular populations
[eng] The population dynamics of the common quail males in Majorca were studied through censuses and captures during two reproductive cycles (2017 and 2018). Results were compared with those obtained in a monitoring program of 13 years (2005-2017) that had taken place in two sites in the northeast of the Iberian Peninsula (Figuerola del Camp in Tarragona, and Alp in Girona). The aim of the study was to investigate the migratory status of the Majorca population and its possible connectivity with other adjacent populations. Being a game species, the knowledge of the phenology and population dynamics throughout the reproductive cycle allow suitable management and conservation. The temporal pattern of abundance of the quail found in Majorca was different from that of the continental populations. A very early phenology of breeding individuals, similar to that found in latitudes of the south of the Iberian Peninsula, suggests the possible winter stay of a fraction of the population in this island. On the other hand, a very delayed phenology in the presence of breeder yearlings suggests an isolation of the Majorca population in relation to the one that breeds in the continent. The lack of synchronization between the abundance pattern of the breeding stock and the cereal cycle, raises more detailed studies on the possible effects this may cause in the population.[cat] Es va estudiar la dinàmica poblacional dels mascles de guàtlera a Mallorca a través de censos i captures durant dos cicles reproductors (2017 i 2018). Els resultats es van comparar amb els obtinguts en un seguiment de 13 anys (2005-2017) que havia tingut lloc en dos localitats del nord-est de la península Ibèrica (Figuerola del Camp a Tarragona, i Alp a Girona). L'objectiu del treball va ser indagar l'estatus migratori de la població mallorquina i la seva possible connectivitat amb altres poblacions adjacents. En tractar-se d'una espècie cinegètica, el coneixement de la fenologia i dinàmica poblacional al llarg del cicle reproductor permeten una adequada gestió i conservació. El patró temporal d'abundància de la guàtlera trobat a Mallorca va ser diferent al de les poblacions continentals. Una fenologia molt primerenca d'individus reproductors, similar a la trobada en latituds del sud de la península Ibèrica, suggereix la possible permanència hivernal d'una fracció de la població en aquesta illa. Per altra banda, una fenologia molt endarrerida en la presència de joves reproductors nascuts dins l'any suggereix un aïllament de la població mallorquina en relació a la que cria al continent. La manca de sincronització entre el patró d'abundància dels efectius reproductors i el cicle del cereal, planteja la realització d'estudis més detallats sobre els possibles efectes que això pugui provocar en la població
Correction to: A Phase II Study Evaluating Combined Neoadjuvant Cetuximab and Chemotherapy Followed by Chemoradiotherapy and Concomitant Cetuximab in Locoregional Oesophageal Cancer Patients
Errors were subsequently identified in the article and the following corrections should be note
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