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Non-specific chronic low back pain is one of common causes of disability and a recurrent medical complaint with high costs. From rehabilitative medicine, physiotherapy programs and general postural recommendations are offered. Although this treatment is aimed to reduce disability, severity of pain and anxiety-depressive symptoms, many patients report partial improvements and recurrence of pain. Therefore, a new approach to treat this pathology with a broaden focus on psychososocial issues that might modulate pain and its evolution is required.
Aims and hypothesis
To assess the effectiveness of two complementary interventions to physiotherapy, such as relaxation techniques (specifically, sophrology) and cognitive behavioral intervention. It is hypothesized that intervention groups will significantly improve their adherence to physiotherapy and will gain control over their pain. Ultimately, this will foster better quality of life.
Longitudinal design with pre-post intervention measures and follow-up appointments (at 6 and 12 months) carried out in a sample of 66 participants. The sample will be divided into three groups: control (physiotherapy), intervention group 1 (physiotherapy & sophrology) and intervention group 2 (physiotherapy & cognitive behavioral intervention). In all groups biomedical aspects regarding type, evolution and characterization of pain as well as several psychosocial factors will be assessed.
Preliminary results are expected by December 2013.
If hypotheses are confirmed, we will be able to provide empirical evidences to justify a multidisciplinary care model for chronic low back pain, which will favor a significant cost reduction in terms of health care and human suffering.
The Mockingbird Gap Clovis site is a surface archaeological site located along Chupadera Draw in central New Mexico. Coring of the draw during archaeological investigation of the Clovis assemblage on the adjacent uplands revealed evidence for a regionally rare continuous, stratified depositional record beginning immediately before the Younger Dryas chronozone (YDC). Thirty sediment samples from the draw adjacent to the archaeological site were analyzed for microinvertebrates (ostracodes and mollusks) and gyrogonites (calcareous algae) to reconstruct its environmental history. Wet-dry cycles marked the presence/absence of microfossils. Based upon microfossils, this investigation highlights environmental change marked by the evolution from wetter/cooler to warmer/drier conditions at the Mockingbird Gap site and its response to climate change and groundwater fluctuations during and after the YDC. Four biofacies are recognized: the pre-Ciénega setting is sterile. Holarctic species near the base of core 08-1 indicate cooling conditions prior to 13,000 cal yr BP during the early Ciénega phase. Warmer, more saline conditions characterize the late-Ciénega biofacies between 11,000 and 10,000 cal yr BP. Presence of gypsum during formation of the post-Ciénega phase and the most salinity tolerant species after 10,000 cal yr BP is consistent with the aridification typifying the early Holocene.
The aim of our study was to identify the influence of such psychological factors as emotional intelligence and perceived competence on caregiver burden in those who care for patients with advanced cancer.
A total of 50 informal caregivers completed self-report assessments of resilience, perceived competence, emotional regulation, positive aspects of care, emotional distress, and burden. We conducted a quantitative study with a cross-sectional design. Descriptive statistics were obtained. Associations between the different variables were assessed using nonparametric and multiple regression analyses.
Participants were mainly female (88%) and had an average of 20 months of caregiving. Their mean age was 47 years (range = 20–79). More than half of scored high on resilience, positive aspects of caring, and emotional distress, moderately on perceived competence, and low on burden. Most caregivers used cognitive restructuring and social support as coping strategies. Inverse negative correlations were observed among emotional distress, emotional state, and burden with perceived competence and positive aspects of caring (p < 0.05). Significant differences were obtained for emotional distress, cognitive restructuring, and resiliency. Multiple regression analyses demonstrated that perceived competence, resiliency, and positive aspects of caring were the main predictors of burden.
Significance of Results:
Resilience, perceived competence, emotional regulation, and positive aspects of care constitute protective factors against caregiver burden. Taken together, these aspects should be promoted by the healthcare staff in order to facilitate caregiver adaptation and well-being.
The magnetic flux emergence can help understand the physical mechanism responsible for solar atmospheric phenomena. Emerging magnetic flux is frequently related to eruptive events, because when emerging they can reconnected with the ambient field and release magnetic energy. We will use a physic-based model to reconstruct the evolution of the solar emission based on the configuration of the photospheric magnetic field. The structure of the coronal magnetic field is estimated by employing force-free extrapolation NLFFF based on vector magnetic field products (SHARPS) observed by HMI instrument aboard SDO spacecraft from Sept. 29 (2013) to Oct. 07 (2013). The coronal plasma temperature and density are described and the emission is estimated using the CHIANTI atomic database 8.0. The performance of the our model is compared to the integrated emission from the AIA instrument aboard SDO spacecraft in the specific wavelengths 171Å and 304Å.
The density and temperature profiles in the solar corona are complex to describe, the observational diagnostics is not easy. Here we present a physics-based model to reconstruct the evolution of the electron density and temperature in the solar corona based on the configuration of the magnetic field imprinted on the solar surface. The structure of the coronal magnetic field is estimated from Potential Field Source Surface (PFSS) based on magnetic field from both observational synoptic charts and a magnetic flux transport model. We use an emission model based on the ionization equilibrium and coronal abundances from CHIANTI atomic database 8.0. The preliminary results are discussed in details.
Some key physical processes that impact the evolution of Earth's atmosphere on time-scale from days to millennia, such as the EUV emissions, are determined by the solar magnetic field. However, observations of the solar spectral irradiance are restricted to the last few solar cycles and are subject to large uncertainties. We present a physics-based model to reconstruct short-term solar spectral irradiance (SSI) variability. The coronal magnetic field is estimated to employ the Potential Field Source Surface extrapolation (PFSS) based on observational synoptic charts and magnetic flux transport model. The emission is estimated to employ the CHIANTI atomic database 8.0. The performance of the model is compared to the emission observed by TIMED/SORCE.
Process-induced defects in electroplated Au interconnect metallization on GaAs devices were detected during the course of reliability testing. Abnormally high lognormal sigma values (σ > 0.7) indicated the existence of a bi-modal failure mechanism. A distinct early lifetime failure mode was observed along with the intrinsic electromigration metallization wear-out failure mode. Physical characterization of the electroplated Au film revealed as-deposited nanoscale voids. Elimination of these voids through process improvement as well as suggested mechanisms for the early failures are discussed.
In this work, we have reported the interface characterization of rf sputtered ZnO/HfO2 in thin film transistor structure by dc current-voltage and admittance spectroscopy. The interface state density (Dit) of 1013 eV−1cm−2 was extracted from the Gp/ω vs ω plot was comparable to value obtained from the subthreshold behavior. The grain boundary trap density (NGB) of 9.12×1012 cm−2 was estimated using Levinson’s model. The interface state density distribution below the conduction band edge shows a decreasing trend with energy below the conduction band edge. We also studied the impact of introducing MgO interfacial layer between ZnO and HfO2 interface as an approach towards decreasing the interface state density.
Strontium titanate (SrTiO3) is a wide-band-gap semiconductor with a variety of novel properties. In this work, bulk single crystal SrTiO3 samples were heated to 1200°C, resulting in the creation of point defects. These thermally treated samples showed large persistent photoconductivity (PPC) at room temperature. Illumination with sub-gap light (>2.9 eV) caused an increase in free-electron concentration by over two orders of magnitude. After the light is turned off, the conductivity persists at room temperature, with essentially zero decay over several days. The results of electron paramagnetic resonance (EPR) measurements suggest that a point defect is responsible for PPC because the photo-induced response of one of the EPR signals is similar to that seen for the PPC. Due to a large barrier for recapture, the photo-excited electron remains in the conduction band, where it contributes to the conductivity.
In this paper, we discuss the characteristics of the InGaP/GaAs heterojunction phototransistors (HPTs) before and after the electrical stress at room temperature and assess the effectiveness of the emitter-ledge passivation. Although an electrical stress given to the phototransistors by keeping a collector current density of 37 A/cm2 for 1 hour at room temperature was too small to affect the room-temperature common-emitter current gain and photocurrent of both HPTs with and without the emitter-ledge passivation, they showed a significant decrease at 420 K due to the room-temperature electrical stress. Nevertheless, the room-temperature common-emitter current gain and photocurrent of the HPT with the emitter-ledge passivation were still higher than those of the HPT without the emitter-ledge passivation. The effectiveness of the emitter-ledge passivation against the electrical stress was more significant than that on the current gain in the dark. In addition to the electrical stress experiment, for a potential application of the InGaP/GaAs HPTs in space, we will irradiate the HPTs with 1-MeV electrons at the Japan Atomic Energy Agency. Both current gain and photocurrent decreased significantly after the electron irradiation. In contrast to the electrical stress, the damage due to the high-energy electron irradiation is a bulk-related phenomenon, and the emitter-ledge passivation does not seem to suppress the degradation.
The influence of threading dislocations (TDs) on the dry thermal oxidation of c-plane gallium nitride (GaN) is investigated for oxidation temperatures above 800°C. The transformation of GaN to gallium oxide (Ga2O3) is preferably found at TDs and grain boundaries, showing enhanced vertical oxidation, compared to defect free surface sites. Therefore, the increase in surface roughness commonly obtained upon oxidation is explained by an inhomogeneous chemical reactivity associated with those crystal defects. Additionally, annealing in an N2 atmosphere showed that also decomposition is favored at such chemically reactive spots. Comparison between decomposition and oxidation suggests that at temperatures above 950°C, the Ga2O3 formation is supported by the decomposition of GaN and subsequent oxidation of the metallic gallium.
Cu (In, Ga) Se2 (CIGS) thin-film solar cells are optimal solar cells for spacecraft, since they have high efficiency, lightweight, flexible and high radiation tolerance. The CIGS solar module without a coverglass to prevent degradation in space has been demonstrated with a small satellite and its electrical performance indicates no degradation as predicted from ground tests. However, the cells need to prevent the damages from other effects in space. The paper introduces some space environment tests and how to improve performance in CIGS cells for spacecraft.
Reliability and degradation processes in broad-area InGaAs-AlGaAs strained quantum well (QW) lasers are under intensive investigation because these lasers are the key components for fiber lasers and amplifiers that have found both industrial and military applications in recent years. Unlike single-mode lasers that were developed for high reliability telecom applications, broad-area lasers were mainly targeted for applications that require less stringent reliability of the lasers until recently. Especially, the lack of field reliability data is a concern for satellite communication systems where high reliability is required of lasers for long-term duration. For our present study, we addressed this concern by performing long-term life-tests of broad-area InGaAs-AlGaAs strained QW lasers and also by studying mechanisms that are responsible for catastrophic degradation of the lasers.
Cadmium Zinc Telluride (CZT) semiconductor crystal properties have been studied extensively with a focus on correlations to their radiation detector performance. The need for defect-free CZT crystal is imperative for optimal detector performance. Extended defects like Tellurium (Te) inclusions, twins, sub-grain boundaries, and dislocations are common defects found in CZT crystals; they alter the electrical properties and, therefore, the crystal's response to high energy radiation. In this research we studied the extended defects in CZT crystals from two separate ingots grown using the low-pressure Bridgman technique. We fabricated several detectors cut from wafers of two separate ingots by dicing, lapping, polishing, etching and applying gold metal contacts on the main surfaces of the crystals. Using infrared (IR) transmission microscope we analyzed the defects observed in the CZT detectors, showing three dimensional scans and plot size distributions of Te inclusions, twins and sub-grain boundaries observed in particular regions of the CZT detectors. We characterized electrical properties of the detectors by measuring bulk resistivity and detector response to gamma radiation. We observed that CZT detectors with more extended defects showed poor opto-electrical properties compared to detectors with fewer defects.
CZT is a semiconductor material that promises to be a good candidate for uncooled gamma radiation detectors. However, to date, we are yet to overcome the technological difficulties in production of large size, defect-free CZT crystals. The most common problem is accumulation of Tellurium precipitates as microscopic inclusions. These inclusions influence the charge collection through charge trapping and electric field distortion. We employed high energy transmission X-ray diffraction techniques to study the quality of the CdZnTe crystals grown by Bridgman Technique. Crystallinity and defects within two different growth set-ups, i.e. with and without choked seeding, were compared by imaging the crystal orientation topography with white beam X-ray diffraction topography (WBXDT). The X-ray diffraction topography results show high correlation with large-area infrared transmission images of the crystals. Grain boundaries that are highly decorated with Te inclusions are observed. Characteristic Te inclusion arrangements as a result of growth conditions are discussed. We also measured the electronic properties of the detectors fabricated from ingots grown using two Bridgman processes, and observed a reduction in electrical resistivity of choked-seeding-grown CdZnTe crystals. Our results show that although choked seeding technique holds a promise in the realization of high quality mono-crystalline CdZnTe, current growth parameters must be improved to obtain defect-free crystals. These results are helpful to attain optimal seeding process for Bridgman-growth of large single crystals of CdZnTe.
Yield shear stress dependence on dislocation density and crystal orientation was studied in bulk GaN crystals by nanoindentation examination. The yield shear stress decreased with increasing dislocation density which is estimated by dark spot density in cathodoluminescence, and it decreased with decreasing nanoindentation strain-rate. It reached and coincided at 11.5 GPa for both quasi-static deformed c-plane (0001) and m-plane (10-10) GaN. Taking into account theoretical Peierls–Nabarro stress and yield stress for each slip system, these phenomena were concluded to be an evidence of heterogeneous mechanism associated plastic deformation in GaN crystal. Transmission electron microscopy and molecular dynamics simulation also supported the mechanism with obtained r-plane (-1012) slip line right after plastic deformation, so called pop-in event. The agreement of the experimentally obtained atomic shuffle energy with the calculated twin boundary energy suggested that the nucleation of the local metastable twin boundary along the r-plane concentrated the indentation stress, leading to an r-plane slip. This nanoindentation examination is useful for the characterization of crystalline quality because the wafer mapping of the yield shear stress coincided the photoluminescence mapping which shows increase of emission efficiency due to reduction of non-radiative recombination process by dislocation.
CZT is a semiconductor material that promises to be a good candidate for uncooled gamma radiation detectors. However, to date, technological difficulties in production of large size defect-free CZT crystals are yet to be overcome. The most common problem is accumulation of tellurium precipitates as microscopic inclusions. These inclusions influence the charge collection through charge trapping and electric field distortion. The common work-around solutions are to fabricate pixelated detectors by either grouping together many small volume CZT crystals to act as individual detectors, or to deposit a pixelated grid of electrical contacts on a larger, but defective, crystal, and selectively collect charge. These solutions are satisfactory in an R&D environment, but are unsuitable for mass production and commercial development. Our modeling effort is aimed at quantifying the various contributions of tellurium inclusions in CZT crystals to the charge generation, transport, and collection, as a function of inclusions size, position, and concentration. We model the energy deposition of gamma photons in the sensitive volume of the detector using LANL’s MCNP code. The electron-hole pairs produced at the energy deposition sites are then transported through the defective crystal and collected as integral charge at the electrical contact sites using CERN’s Garfield software package. The size and position distribution of tellurium inclusions is modeled by sampling experimentally measured distributions of such inclusions on a variety of commercially-grown CZT crystals using IR microscopy and image processing software packages.
CuxO thin films have been deposited on a quartz substrate by reactive radio frequency (rf) magnetron sputtering at different target powers Pt (140-190 W) while keeping other growth process parameters fixed. Room-temperature photoluminescence (PL) measurements indicate considerable improvement of crystallinity for the films deposited at Pt>170 W, with most pronounced excitonic features being observed in the film grown using Pt=190 W. These results corroborate well with the surface morphology of the films, which was found more flat, smooth and homogeneous for Pt >170 W films in comparison with those deposited at lower powers.
The stability of green phosphorescent OLEDs with different structures was evaluated through constant-current stressing. Through the modifications of the ITO anode by different plasma treatments and the hole transport layer (HTL) by incorporating inorganic dopants, we proved that energy level misalignment at the ITO/HTL interface leads to localized joule heating, accelerating defect generation and luminescence decay. Pulsed current stressing was then employed to suppress the joule-heating effect so as to differentiate the thermal and nonthermal factors governing the device degradation. For OLEDs with a large energy barrier at the ITO/HTL interface, the effective lifetime was markedly increased under pulsed operation, whereas in OLEDs with an appropriate interfacial energy level alignment, pulsed stressing with 10% duty cycle only improved the effective half life by ∼15% as compared to continuous-wave stressing, indicating a minor role played by joule heating.