Nanophotonic boost of intermolecular energy transfer

We propose a scheme for efficient long-range energy transfer between two distant light emitters separated by more than one wavelength of light, i.e. much beyond the classical Forster radius. A hybrid nanoantenna-waveguide system mediates the transmission of energy, showing enhancements up to 10^8 as compared to vacuum. Our model shows how energy transfer in nanostructured media can be boosted, beyond the simple donor Purcell enhancement, and in particular for large donor-acceptor separations. The scheme we propose connects realistic emitters and could lead to practical on-chip implementations.Comment: 9 pages, 4 figure

Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

Densidad y dimensiones de la fibra de Gmelina arborea en árboles de rápido crecimiento en Costa Rica: relación con el rango de de crecimiento

The objective of this research was to determine growth rate effects measured in tree diameter on wood density parameters (mean, minimum, maximum and intra-ring variation) and in fiber dimensions (wall thickness, fiber width, lumen diameter and fiber length) of trees from fast growth plantations. Thirty mature trees were sampled from thirty different fast-growth plantations with a wide growth rate in Costa Rica. A disc was cut from each tree at DBH. The wood density parameters and fiber dimensions were determined in each growth ring. Some wood density parameters and fiber dimensions were related with growth rate. The minimum and mean density, cell wall thickness, fiber width and lumen diameter decreased with increase in growth rate. Intra-ring wood density variation increased with growth rate but the weak correlation was established. Maximum wood density was not found correlation with growth rate. A pronounced decrease was presented in minimum and mean density from 0 to 20 mm/year and after to 45 mm/year. A pronounced decrease and increase with increase in growth rate were presented in the fiber length and intra-ring wood density, respectively. Lumen diameter and fiber width presented few variations, until 40 mm/year; however, they showed decrease after this growth rate value.La Gmelina arborea es utilizada en plantaciones debido a que las practicas silviculturales producen altas tasas de crecimiento del árbol. El presente trabajo tiene el objetivo de establecer los efectos de la tasa de crecimiento en los parámetros de densidad de la madera (media, máxima, mínima y la variación intra-anillo) y las dimensiones de la fibra (largo, ancho, diámetro del lumen y espesor de pared) en árboles de plantaciones de rápido crecimiento. Fueron seleccionadas treinta árboles de treinta 30 plantaciones diferentes próximas al turno de rotación con una amplia tasa de crecimiento. Un disco a la altura del pecho fue cortado en cada uno de los árboles. Los parámetros de densidad y dimensiones de las fibras fueron determinadas en cada anillo de crecimiento. Algunos de los parámetros de la densidad y las dimensiones de la fibra fueron correlacionados con la tasa de crecimiento. La densidad mínima y el promedio, espesor de pared celular y diámetro del lumen diminuyen con el incremento de la tasa de crecimiento. La variación intra-anillo incremento, pero una débil correlación fue encontrada. La densidad máxima no presentó correlación. Una gran disminución de la densidad mínima y la densidad media fue encontrada cuando la tasa de crecimiento se encuentra entre 0 y 20 mm/año o superior a 45 mm/año. Un pronunciado decrecimiento e incremento con el incremento de la tasa de crecimiento fue encontrado en la longitud de la fibra y la variación intra-anillo, respectivamente. El diámetro del lumen y ancho de la fibra presentaron pocas variaciones cuando la tasa de crecimiento es menor a 40 mm/año, sin embargo, estos mostraron un decrecimiento luego del mencionado valor

study of 10,574 cases from five Portuguese hospitals

WOS: 000363056900005publishersversionpublishe

Glucose-evoked Na+,K+-ATPase modulation in pancreatic ß-cells from normal and impaired glucose tolerance: role of AMPK

Na+,K+-ATPase is regulated by glucose in pancreatic ß-cells, a process that is altered in glucose impaired tolerance. Although AMP dependent protein kinase (AMPK), a metabolic sensor, is believed to be central in the signal transduction cascade underlying the Na+,K+-ATPase regulation in pancreatic β-cells, its role remains unknown. The aim of this work was to clarify the role of AMPK in glucoseevoked inhibition of Na+,K+-ATPase and to evaluate whether AMPK is differently regulated in pancreatic β-cells from subjects with normal and impaired glucose tolerance. Pancreatic β-cells or islets from normal (control) or glucose-intolerant Wistar rats (GIR) were isolated and cultured. After a pre-incubation (30min) with 2.1mM glucose (G2), batches were challenged for 20min with 2.1 or 8.4mM glucose (G8) in the presence or absence of AMPK agonist (AICAR, 1mM) and antagonist (Compound C (CC), 10μM). Na+,K+-ATPase activity was assessed by quantification of Pi, in the absence and in presence of 1mM ouabain. Phosphorylation levels of α1 subunit of Na+,K+-ATPase- (Ser-23) and αAMPK-(Thr-172) was evaluated by Western blot (WB). In G2 Na+,K+-ATPase activity from normal and GIR β-cell was similar (0.184±0.030 and 0.186±0.020 μmolPi/min/mgProt, respectively). Challenging the β-cells with G8 evoked a lower inhibition of Na+,K+- ATPase activity in GIR (40%) compared to controls (62%). In control β-cell, AICAR abolished glucoseinduced Na+,K+-ATPase inhibition (0,166±0.011 μmolPi/min/mg) whereas CC had no effect. In the contrast, CC significantly potentiated glucose-evoked inhibition of Na+,K+-ATPase in GIR β-cells, reaching values similar to the controls (66%), For both GIR and control islets, G8 induced a 50% decrease of AMPK phosphorylation level compared to G2. CC mimicked the effect of G8, but was less efficient in GIR. Concomitantly, α1-Na+,K+-ATPase-(Ser-23) phosphorylation level was increased upon G8 or CC stimulation, compared to G2 or AICAR. These results suggest that AMPK plays a key role in the signaling mechanism underlying glucoseinduced modulation of the pump, a process dependent on phosphorylation cascades, and that the defect in GIR must be upstream of AMPK. Glucose-induced inhibition of Na+,K+-ATPase may result from AMPK inhibition by the fuel metabolism and subsequent activation of PKC, known to phosphorylate α1-Na+,K+-ATPase-(Ser-23). This mechanism is impaired in GIR, thus potentially contributing to the impaired glucose-induced insulin secretion in IGT. Occurring prior to overt type 2 diabetes, this might be a feature in the disease development

Ocean data manager: practical software for oceanographic sensors

Peer Reviewe

(Re)construção de Percursos Formativos ao Longo da Vida: O caso dos Cursos de Educação e Formação de Adultos (EFA)

Os Cursos de Educação e Formação de Adultos (adiante designados Cursos EFA), assumeme como uma das respostas formativas e de qualificação disponíveis no sistema de educação e dequalificação em Portugal. Desde a sua criação, até à data, ocorreram alterações várias, sob oponto de vista legal, metodológico e pedagógico. Procurou-se efectuar uma breve descrição daoferta EFA, apontando-se duas dimensões: (i) a sua génese e evolução; (ii) as especificidades doeu modelo de formação/ estrutura curricular, relacionando essas dimensões com a importância doprincípio de Aprendizagem ao Longo da Vida (ALV). Como palavras-chave destaque paraeducação e formação de adultos e aprendizagem ao longo da vida