388 research outputs found
Infrared Phase-Change Meta-Devices with In-Situ Switching
This is the author accepted manuscript. The final version is available from the European Phase Change and Ovonics Symposium via the link in this recordWe describe a possible device design approach and an experimental test platform suitable for the
realization and characterization of phase-change based meta-devices incorporating in-situ
switching and operating at infrared wavelengths. Measurements on such a prototype device
working at 1.55 µm are presented.US Naval Research LaboratoriesEngineering and Physical Sciences Research Council (EPSRC
Análisis del plano sagital en las escoliosis idiopáticas tratadas con instrumentación Cotrel-Dubousset
Se analiza la evolución del plano sagital en 50 enfermos con escoliosis idiopática
intervenidos mediante artrodesis posterior con instrumentación de Cotrel-Dubousset con un seguimiento
medio de 72 meses. Se recogieron los valores evolutivos de cifosis torácica medida entre
T5 y T12 y de lordosis lumbar medida entre Ll y L5. Las curvas escolióticas fueron clasificadas
según King et al. Los resultados obtenidos mostraron que no existía una variación global significativa
de la cifosis torácica tras la cirugía. Sólo en aquellos enfermos que previamente existía
una hipocifosis torácica existía una mejoría estadísticamente significativa de la misma con la intervención.
Se evidenció una clara tendencia al incremento de la cifosis torácica con el tiempo.
La lordosis lumbar se mantuvo, en la mayoría de los casos, dentro de límites fisiológicos. La instrumentación
de Cotrel-Dubousset ofrece ventajas evidentes respecto a instrumentaciones previas
en lo que respecta a la obtención de una curva más fisiológica en el plano sagital. Permite
corregir la hipocifosis torácica severa y mantener la lordosis lumbar dentro de límites normales,
incluso en instrumentaciones por debajo de L3.Sagittal plane analysis of 50 patients with idiopathic scoliosis treated with Cotrel-
Dubousset instrumentation was performed. Mean follow-up was 72 months. The values of thoracic
kyphosis from T5 to T12 and lumbar lordosis from L1 to L5 were retrospectively reviewed.
Scoliotic curves were classified according to King et al. The results showed that there was not any
significant change in thoracic kyphosis after surgery. Only those patients with preoperative thoracic
hypokyphosis achieved a significant realignment. There was an obvious increase of thoracic
kyphosis with time. Lumbar lordosis was maintained within normal limits in the mayority of patients.
Cotrel-Dubousset instrumentation achieves better sagittal alignment than previous systems.
It corrects thoracic hypokyphosis and preserves lumbar lordosis, even when the instrumentation
is carried out lower than L3
Avulsión de la tuberosidad anterior de la tibia asociada a rotura del tendón cuadricipital
Se presenta 1 caso de fractura-avulsión de la tuberosidad anterior de la tibia asociada
a rotura del tendón cuadricipital en un varón de 16 años. Tras el tratamiento quirúrgico de
la fractura tuberositaria, y a pesar de haber pasado inicialmcnte inadvertida la lesión tendinosa,
el resultado final a los 9 meses ha sido satisfactorio.A case of avulsion-fracture of the anterior tibial tubercle associated with rupture
of the cuadricipital tendon in a 16-ycars-old boy is presented. After surgical treatment, in spite of
having overlooked initially the tendinous lesion, the functional result at 9 months follow-up has
been satisfactory
The weighted independent domination problem: ILP model and algorithmic approaches
This work deals with the so-called weighted independent domination problem, which is an N P -hard combinatorial optimization problem in graphs. In contrast to previous theoretical work from the liter- ature, this paper considers the problem from an algorithmic perspective. The first contribution consists in the development of an integer linear programming model and a heuristic that makes use of this model. Sec- ond, two greedy heuristics are proposed. Finally, the last contribution is a population-based iterated greedy algorithm that takes profit from the better one of the two developed greedy heuristics. The results of the compared algorithmic approaches show that small problem instances based on random graphs are best solved by an efficient integer linear programming solver such as CPLEX. Larger problem instances are best tackled by the population-based iterated greedy algorithm. The experimental evaluation considers random graphs of different sizes, densities, and ways of generating the node and edge weights
The Weighted Independent Domination Problem: ILP Model and Algorithmic Approaches
This work deals with the so-called weighted independent domination problem, which is an -hard combinatorial optimization problem in graphs. In contrast to previous work, this paper considers the problem from a non-theoretical perspective. The first contribution consists in the development of three integer linear programming models. Second, two greedy heuristics are proposed. Finally, the last contribution is a population-based iterated greedy metaheuristic which is applied in two different ways: (1) the metaheuristic is applied directly to each problem instance, and (2) the metaheuristic is applied at each iteration of a higher-level framework---known as construct, merge, solve \& adapt---to sub-instances of the tackled problem instances. The results of the considered algorithmic approaches show that integer linear programming approaches can only compete with the developed metaheuristics in the context of graphs with up to 100 nodes. When larger graphs are concerned, the application of the populated-based iterated greedy algorithm within the higher-level framework works generally best. The experimental evaluation considers graphs of different types, sizes, densities, and ways of generating the node and edge weights
Nutrient and herbivore alterations cause uncoupled changes in producer diversity, biomass and ecosystem function, but not in overall multifunctionality
Altered nutrient cycles and consumer populations are among the top anthropogenic influences on ecosystems. However, studies on the simultaneous impacts of human-driven environmental alterations on ecosystem functions, and the overall change in system multifunctionality are scarce. We used estuarine tidal flats to study the effects of changes in herbivore density and nutrient availability on benthic microalgae (diversity, abundance and biomass) and ecosystem functions (N2-fixation, denitrification, extracellular polymeric substances -EPS- as a proxy for sediment cohesiveness, sediment water content as a proxy of water retention capacity and sediment organic matter). We found consistent strong impacts of modified herbivory and weak effects of increased nutrient availability on the abundance, biomass and diversity of benthic microalgae. However, the effects on specific ecosystem functions were disparate. Some functions were independently affected by nutrient addition (N2-fixation), modified herbivory (sediment organic matter and water content), or their interaction (denitrification), while others were not affected (EPS). Overall system multifunction remained invariant despite changes in specific functions. This study reveals that anthropogenic pressures can induce decoupled effects between community structure and specific ecosystem functions. Our results highlight the need to address several ecosystem functions simultaneously for better ecosystem characterization and management.Instituto de Limnología "Dr. Raul A. Ringuelet
Evaluating the surface circulation in the Ebro delta (northeastern Spain) with quality-controlled high-frequency radar measurements
The Ebro River delta is a relevant marine protected area in the western
Mediterranean. In order to promote the conservation of its ecosystem and
support operational decision making in this sensitive area, a three-site
standard-range (13.5 MHz) CODAR SeaSonde high-frequency (HF) radar was
deployed in December 2013. The main goal of this work is to explore basic
features of the sea surface circulation in the Ebro deltaic region as derived
from reliable HF radar surface current measurements. For this aim, a combined
quality control methodology was applied: firstly, 1-year long (2014)
real-time web monitoring of nonvelocity-based diagnostic parameters was
conducted to infer both radar site status and HF radar system performance.
The signal-to-noise ratio at the monopole exhibited a consistent monthly
evolution, although some abrupt decreases (below 10 dB), occasionally
detected in June for one of the radar sites, impacted negatively on the
spatiotemporal coverage of total current vectors. It seemed to be sporadic
episodes since radar site overall performance was found to be robust during
2014. Secondly, a validation of HF radar data with independent in situ
observations from a moored current meter was attempted for May–October 2014.
The accuracy assessment of radial and total vectors revealed a consistently
high agreement. The directional accuracy of the HF radar was rated at better
than 8°. The correlation coefficient and root mean square error
(RMSE) values emerged in the ranges [0.58–0.83] and
[4.02–18.31] cm s−1, respectively. The analysis of the monthly
averaged current maps for 2014 showed that the HF radar properly represented
basic oceanographic features previously reported, namely, the predominant
southwestward flow, the coastal clockwise eddy confined south of the Ebro
delta mouth, or the Ebro River impulsive-type freshwater discharge. The EOF
analysis related the flow response to local wind forcing and confirmed that
the surface current field evolved in space and time according to three
significantly dominant modes of variability
Plasmonically-enhanced all-optical integrated phase-change memory
This is the final version. Available on open access from the Optical Society of America via the DOI in this record.Integrated phase-change photonic memory devices offer a novel route to non-volatile storage and computing that can be carried out entirely in the optical domain, obviating the necessity for time and energy consuming opto-electrical conversions. Such memory devices generally consist of integrated waveguide structures onto which are fabricated small phase-change memory cells. Switching these cells between their amorphous and crystalline states modifies significantly the optical transmission through the waveguide, so providing memory, and computing, functionality. To carry out such switching, optical pulses are sent down the waveguide, coupling to the phase-change cell, heating it up, and so switching it between states. While great strides have been made in the development of integrated phase-change photonic devices in recent years, there is always a pressing need for faster switching times, lower energy consumption and a smaller device footprint. In this work, therefore, we propose the use of plasmonic enhancement of the light-matter interaction between the propagating waveguide mode and the phase-change cell as a means to faster, smaller and more energy-efficient devices. In particular, we propose a form of plasmonic dimer nanoantenna of significantly sub-micron size that, in simulations, offers significant improvements in switching speeds and energies. Write/erase speeds in the range 2 to 20 ns and write/erase energies in the range 2 to 15 pJ were predicted, representing improvements of one to two orders of magnitude when compared to conventional device architectures.Engineering and Physical Sciences Research Council (EPSRC
Resistance to Bleomycin-Induced Lung Fibrosis in MMP-8 Deficient Mice Is Mediated by Interleukin-10
BACKGROUND: Matrix metalloproteinases (MMPs) may have pro and antifibrotic roles within the lungs, due to its ability to modulate collagen turnover and immune mediators. MMP-8 is a collagenase that also cleaves a number of cytokines and chemokines. METHODOLOGY AND PRINCIPAL FINDINGS: To evaluate its relevance in lung fibrosis, wildtype and Mmp8(-/-) mice were treated with either intratracheal bleomycin or saline, and lungs were harvested at different time points. Fibrosis, collagen, collagenases, gelatinases, TGFβ and IL-10 were measured in lung tissue. Mmp8(-/-) mice developed less fibrosis than their wildtype counterparts. This was related to an increase in lung inflammatory cells, MMP-9 and IL-10 levels in these mutant animals. In vitro experiments showed that MMP-8 cleaves murine and human IL-10, and tissue from knockout animals showed decreased IL-10 processing. Additionally, lung fibroblasts from these mice were cultured in the presence of bleomycin and collagen, IL-10 and STAT3 activation (downstream signal in response to IL-10) measured by western blotting. In cell cultures, bleomycin increased collagen synthesis only in wildtype mice. Fibroblasts from knockout mice did not show increased collagen synthesis, but increased levels of unprocessed IL-10 and STAT3 phosphorylation. Blockade of IL-10 reverted this phenotype, increasing collagen in cultures. CONCLUSIONS: According to these results, we conclude that the absence of MMP-8 has an antifibrotic effect by increasing IL-10 and propose that this metalloprotease could be a relevant modulator of IL-10 metabolism in vivo
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