Type-II InAsxSb1-x/InAs quantum dots for midinfrared applications: Effect of morphology and composition on electronic and optical properties

InSb-based self-assembled quantum dots are very promising for the midinfrared (3-5μm) optical range. We have analyzed the effect of geometry and composition on the electronic structure and optical spectra of InAsx Sb1-x /InAs dots. The calculated transition energies agree well with the available experimental data. The results show that the geometry of the dot can be estimated from the optical spectra if the composition is known, and vice versa. © 2009 The American Physical Society

Clinical comparative effectiveness research through the lens of healthcare decisionmakers

Background: Healthcare expenditures in the United States exceed the healthcare expenditures of other countries, yet relatively unfavorable health outcomes persist. Despite the emergence of numerous evidence-based interventions, wide variations in clinical care have caused disparities in quality of care and cost. Comparative effectiveness and cost effectiveness research may better guide healthcare decisionmakers in determining which interventions work best, for which populations, under which conditions, and at what cost. Methods: This article reviews national health policies that promote comparative effectiveness research (CER), healthcare decisionmaker roles in CER, methodological approaches to CER, and future implications of CER. Results: This article provides a brief summary of CER health policy up to the Patient Protection and Affordable Care Act and its establishment of the Patient-Centered Outcomes Research Institute (PCORI). Through PCORI, participatory methods for engaging healthcare decisionmakers in the entire CER process have gained momentum as a strategy for improving the relevance of research and expediting the translation of research into practice. Well-designed, methodologically rigorous observational studies and randomized trials conducted in real-world settings have the potential to improve the quality, generalizability, and transferability of study findings. Conclusion: Learning health systems and practice-based research networks provide the infrastructure for advancing CER methods, generating local solutions to high-quality cost-effective care, and transitioning research into implementation and dissemination science—all of which will ultimately guide health policy on clinical care, payment for care, and population health

The Galactic disk mass-budget : II. Brown dwarf mass-function and density

In this paper, we extend the calculations conducted previously in the stellar regime to determine the brown dwarf IMF in the Galactic disk. We perform Monte Carlo calculations taking into account the brown dwarf formation rate, spatial distribution and binary fraction. Comparison with existing surveys seems to exclude a power-law MF as steep as the one determined in the stellar regime below 1 \msol and tends to favor a more flatish behaviour. Comparison with methane-dwarf detections tends to favor an eventually decreasing form like the lognormal or the more general exponential distributions determined in the previous paper. We calculate predicting brown dwarf counts in near-infrared color diagrams and brown dwarf discovery functions. These calculations yield the presently most accurate determination of the brown dwarf census in the Galactic disk. The brown dwarf number density is comparable to the stellar one, $n_{BD}\simeq n_\star\simeq 0.1$ pc$^{-3}$. The corresponding brown dwarf mass density, however, represents only about 10% of the stellar contribution, i.e. \rho_{BD}\simle 5.0\times 10^{-3} \mvol. Adding up the local stellar density determined previously yields the density of star-like objects, stars and brown dwarfs, in the solar neighborhood \rho_\odot \approx 5.0\times 10^{-2} \mvol.Comment: 39 pages, Latex file, uses aasms4.sty, to be published in ApJ, corrected version with correct figure

Important factors to consider when treating children with chronic fatigue sndrome/myalgic encephalomyelitis (CFS/ME):perspectives of health professionals from specialist services

Background Paediatric Chronic Fatigue Syndrome (CFS)/Myalgic Encephalomyelitis (ME) is relatively common and disabling. Improving treatment requires the development of Patient Reported Outcome Measures (PROMs) that enable clinicians and researchers to collect patient-centred evidence on outcomes. Health professionals are well placed to provide clinical insight into the condition, its treatment and possible outcomes. This study aimed to understand the perspectives of specialist paediatric CFS/ME health professionals and identify outcomes that are clinically important. Methods Focus groups and interviews were held with 15 health professionals involved in the care of children with CFS/ME from the four largest specialist paediatric CFS/ME services in the NHS in England. A range of clinical disciplines were included and experience in paediatric CFS/ME ranged from 2 months to 25 years. Ten participants (67%) were female. Focus groups and interviews were recorded, transcribed verbatim and data were analysed using thematic analysis. Results All health professionals identified the impact of CFS/ME across multiple aspects of health. Health professionals described four areas used to assess the severity of the illness and outcome in children: 1) symptoms; 2) physical function; 3) participation (school, activities and social life); and 4) emotional wellbeing. They also described the complexity of the condition, contextual factors and considerations for treatment to help children to cope with the condition. Conclusions Clinically important outcomes in paediatric CFS/ME involve a range of aspects of health. Health professionals consider increases in physical function yet maintaining school functioning and participation more widely as important outcomes from treatment. The results are similar to those described by children in a recent study and will be combined to develop a new child-specific PROM that has strong clinical utility and patient relevanc

Continuous intraoperative nerve monitoring in thyroidectomy using automatic periodic stimulation in 256 at-risk nerves

INTRODUCTION: Automatic periodic stimulation of the vagal nerve during thyroidectomy provides real-time feedback of recurrent laryngeal nerve function intraoperatively. To assess the validity of this device, the ability of monitoring to predict recurrent laryngeal nerve palsy was determined and the incidence of recurrent laryngeal nerve palsy recorded. MATERIALS AND METHODS: All thyroidectomies using APS® (Automatic Periodic Stimulation, Medtronic) nerve monitoring were reviewed over a 27-month period. Changes in signal amplitude and latency during thyroidectomy were recorded from saved data. Postoperative fibreoptic laryngoscopy determined the incidence of vocal cord immobility and recovery of nerve function was assessed from follow-up letters. RESULTS: A total of 256 at-risk nerves were examined (132 hemi- and 62 total thyroidectomies) in cases involving benign and malignant disease. Permanent recurrent laryngeal nerve palsy occurred in six (2.3%) lobectomies and transient recurrent laryngeal nerve palsy occurred in two lobectomies (< 1%). Sensitivity for detecting postoperative vocal cord immobility was 100% and specificity 85% if the end amplitude was 50% below baseline. The positive predictive value when amplitude was 50% below baseline was 18%. The negative predictive value when amplitude was 50% above or equal to baseline was 100%. Intraoperatively, the amplitude was 50% below baseline more frequently in the vocal cord immobility group (t-test, P < 0.015). No vagal nerve complications occurred. CONCLUSION: Whilst the incidence of recurrent laryngeal nerve palsy is comparable to rates in the literature, the incidence of transient palsy is lower than published averages. APS is able to reliably predict recurrent laryngeal nerve palsy based on end amplitude

Southeast Atlantic Ocean aerosol direct radiative effects over clouds: comparison of observations and simulations

Absorbing aerosols exert a warming or a cooling effect on the Earth’s system, depending on the circumstances. The direct radiative effect (DRE) of absorbing aerosols is negative (cooling) at the top-of-the-atmosphere (TOA) over a dark surface like the ocean, as the aerosols increase the planetary albedo, but it is positive (warming) over bright backgrounds like clouds. Furthermore, radiation absorption by aerosols heat the atmosphere locally, and, through rapid adjustments of the atmospheric column and cloud dynamics, the net effect can be amplified considerably. We developed a technique to study the absorption of radiation of smoke over low lying clouds using satellite spectrometry. The TOA DRE of smoke over clouds is large and positive over the southeast Atlantic Ocean off the west coast of Africa, which can be explained by the large decrease of reflected radiation by a polluted cloud, especially in the UV. However, general circulation models (GCMs) fail to reproduce these strong positive DRE, and in general GCMs disagree on the magnitude and even sign of the aerosol DRE in the southeast Atlantic region. Our satellite-derived DRE measurements show clear seasonal and inter-annual variations, consistent with other satellite measurements, which are not reproduced by GCMs. A comparison with model results showed discrepancies with the Ångström exponent of the smoke aerosols, which is larger than assumed in simulations, and a sensitivity to emission scenarios. However, this was not enough to explain the discrepancies, and we suspect that the modeling of cloud distributions and microphysics will have the necessary larger impact on DRE that will explain the differences between observations and modeling

Southern Ocean albedo, inter-hemispheric energy transports and the double ITCZ: global impacts of biases in a coupled model

A causal link has been invoked between inter-hemispheric albedo, cross-equatorial energy transport and the double-IntertropicalConvergence Zone (ITCZ) bias in climate models. Southern Ocean cloud biases are a major determinant of inter-hemispheric albedo biases in many models, including HadGEM2-ES, a fully coupled model with a dynamical ocean. In this study, targeted albedo corrections are applied to explore the dynamical response to artificially reducing these biases. The Southern Hemisphere jet increases in strength in response to the increased tropical-extratropical temperature gradient, with increased energy transport into the mid-latitudes in the atmosphere, but no improvement is observed in the double-ITCZ bias or atmospheric cross-equatorial energy transport. The majority of the adjustment in energy transport in the tropics is achieved in the ocean, with the response further limited to the Pacific Ocean. As a result, the frequently argued teleconnection between the Southern Ocean and tropical precipitation biases is muted. Further experiments in which tropical longwave biases are also reduced do not yield improvement in the representation of the tropical atmosphere. These results suggest that the dramatic improvements in tropical precipitation that have been shown in previous studies may be a function of the lack of dynamical ocean and/or the simplified hemispheric albedo bias corrections applied in that work. It further suggests that efforts to correct the double ITCZ problem in coupled models that focus on large-scale energetic controls will prove fruitless without improvements in the representation of atmospheric processes.MKH, MC and JMH were supported by the Natural Environment Research Council/Department for International Development via the Future Climates for Africa (FCFA) funded project ’Improving Model Processes for African Climate’ (IMPALA, NE/M017265/1). JMH and AJ were supported by the Joint UK DECC/Defra Met Office Hadley Centre Climate Programme (GA01101)

Resection and resolution of bone marrow lesions associated with an improvement of pain after total knee replacement: a novel case study using a 3-Tesla metal artefact reduction MRI sequence

We present our case report using a novel metal artefact reduction magnetic resonance imaging (MRI) sequence to observe resolution of subchondral bone marrow lesions (BMLs), which are strongly associated with pain, in a patient after total knee replacement surgery. Large BMLs were seen preoperatively on the 3-Tesla MRI scans in a patient with severe end stage OA awaiting total knee replacement surgery. Twelve months after surgery, using a novel metal artefact reduction MRI sequence, we were able to visualize the bone-prosthesis interface and found complete resection and resolution of these BMLs. This is the first reported study in the UK to use this metal artefact reduction MRI sequence at 3-Tesla showing that resection and resolution of BMLs in this patient were associated with an improvement of pain and function after total knee replacement surgery. In this case it was associated with a clinically significant improvement of pain and function after surgery. Failure to eradicate these lesions may be a cause of persistent postoperative pain that is seen in up to 20% of patients following TKR surgery

Black carbon physical and optical properties across northern India during pre-monsoon and monsoon seasons

Black carbon (BC) is known to have major impacts on both climate and human health and is therefore of global importance, particularly in regions close to large populations that have strong sources. The size-resolved mixing state of BC-containing particles was characterised using a single-particle soot photometer (SP2). The study focusses on the Indo-Gangetic Plain (IGP) during the pre-monsoon and monsoon seasons. Data presented are from the UK Facility for Airborne Atmospheric Measurements BAe-146 research aircraft that performed flights during the pre-monsoon (11 and 12 June) and monsoon (30 June to 11 July) seasons of 2016. Over the IGP, BC mass concentrations were greater (1.95 µg m−3) compared to north-west India (1.50 µg m−3) and north-east India (0.70 µg m−3) during the pre-monsoon season. Across northern India, two distinct BC modes were recorded; a mode of small BC particles (core diameter <0.16 µm and coating thickness <50 nm) and a mode of moderately coated BC (core diameter <0.22 µm and coating thickness of 50–200 nm). The IGP and north-east India locations exhibited moderately coated black carbon particles with enhanced coating thicknesses, core sizes, mass absorption cross sections, and scattering enhancement values compared to much lower values present in the north-west. The coating thickness and mass absorption cross section increased with altitude (13 %) compared to those in the boundary layer. As the monsoon arrived across the region, mass concentration of BC decreased over the central IGP and north-east locations (38 % and 28 % respectively), whereas for the north-west location BC properties remained relatively consistent. Post-monsoon onset, the coating thickness, core size, mass absorption cross section, and scattering enhancement values were all greatest over the central IGP much like the pre-monsoon season but were considerably reduced over both north-east and north-west India. Increases in mass absorption cross section through the atmospheric column were still present during the monsoon for the north-west and central IGP locations, but less so over the north-east due to lack of long-range transport aerosol aloft. Across the Indo-Gangetic Plain and north-east India during the pre-monsoon and monsoon seasons, solid-fuel (wood burning) emissions form the greatest proportion of BC with moderately coated particles. However, as the monsoon develops in the north-east there was a switch to small uncoated BC particles indicative of traffic emissions, but the solid-fuel emissions remained in the IGP into the monsoon. For both seasons in the north-west, traffic emissions form the greatest proportion of BC particles. Our findings will prove important for greater understanding of the BC physical and optical properties, with important consequences for the atmospheric radiative forcing of BC-containing particles. The findings will also help constrain the regional aerosol models for a variety of applications such as space-based remote sensing, chemistry transport modelling, air quality, and BC source and emission inventories