525 research outputs found

    Self-aligned charge read-out for InAs nanowire quantum dots

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    A highly sensitive charge detector is realized for a quantum dot in an InAs nanowire. We have developed a self-aligned etching process to fabricate in a single step a quantum point contact in a two-dimensional electron gas and a quantum dot in an InAs nanowire. The quantum dot is strongly coupled to the underlying point contact which is used as a charge detector. The addition of one electron to the quantum dot leads to a change of the conductance of the charge detector by typically 20%. The charge sensitivity of the detector is used to measure Coulomb diamonds as well as charging events outside the dot. Charge stability diagrams measured by transport through the quantum dot and charge detection merge perfectly.Comment: 11 pages, 3 figure

    Relational Operant Skills Training Increases Standardized Matrices Scores in Adolescents: A Stratified Active-Controlled Trial

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    In recent years, small-scale studies have suggested that we may be able to substantially strengthen children's general cognitive abilities and intelligence quotient (IQ) scores using a relational operant skills training program (SMART). Only one of these studies to date has included an active Control Condition, and that study reported the smallest mean IQ rise. The present study is a larger stratified active-controlled trial to independently test the utility of SMART training for raising Non-verbal IQ (NVIQ) and processing speed. We measured personality traits, NVIQs, and processing speeds of a cohort of school pupils (aged 12–15). Participants were allocated to either a SMART intervention group or a Scratch computer coding control group, for a period of 3 months. We reassessed pupils’ NVIQs and processing speeds after the 3-month intervention. We observed a significant mean increase in the SMART training group’s (final nexp = 43) NVIQs of 5.98 points, while there was a nonsignificant increase of 1.85 points in the Scratch active-control group (final ncont = 27). We also observed an increase in processing speed across both conditions (final nexp = 70; ncont = 55) over Time. Our results suggest that relational skills training may be useful for improving performance on matrices tasks, and perhaps in future, accelerating children’s progression toward developmental milestones

    Risk Factors for COVID-19 Infection among Healthcare Workers in North-East Nigeria

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    Healthcare workers (HCWs) face an unprecedented higher risk of COVID-19 infection due to their work and exposure. In this study, we aim to examine the associated risk factors for COVID-19 infection among HCWs in North-East Nigeria. We used data collected retrospectively among a cohort of clinical and non-clinical HCWs in six healthcare facilities in Adamawa State, Nigeria. We estimated the marginal probability of COVID-19 infection among HWCs using alternating logistic regression via the generalized estimating equations (GEE) approach. Among the 318 HCWs, 178 (55.97%) were males, mean (±SD) age was 36.81 (±8.98), 237 (74.76%) were clinical, and 80 (25.24) were non-clinical staff. The overall prevalence of COVID-19 was 16.67% among HCWs. After adjusting for other variables in the model, our results showed that clinical staff had a 5-fold higher risk of COVID-19 infection than non-clinical staff (aOR = 5.07, 95% CI: 1.32–19.52). Moreover, significant exposure risk factors for COVID-19 infection for HCWs increase with age, time spent attending to patients, caring for COVID-19 patients, and having worked with COVID-19 samples, while the risk decreases with the use of an N95 mask. Our findings suggested that the burden of COVID-19 infection is higher for clinical staff than non-clinical staff, and increasing age contributed to the increased risk

    Adaptability and psychological flexibility: Overlapping constructs?

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    Adaptability is purported to be a key mental resource and refers to an individual's cognitive, behavioral, and emotional regulation (or adjustment) in situations of change, novelty, and uncertainty. Psychological flexibility refers to a person's capacity to allow experience and acceptance of negative thoughts and feelings with mindful awareness guided by a commitment to goal-driven action according to their self-chosen values. It is important to disentangle these cognate constructs—adaptability and psychological flexibility—so that the unique variance attributable to each can be estimated, and interventions and resources can be directed with greater precision. The current study explored the potential overlap between adaptability and psychological flexibility by conducting an online cross-sectional survey (n = 205), with measures of adaptability, psychological flexibility, wellbeing, and psychological distress. A confirmatory factor analysis suggested considerable overlap, but sufficient discrimination between the two constructs. Structural equation modelling showed that adaptability was related to psychological wellbeing, but not related to psychological distress after accounting for the effects of psychological flexibility

    Who is more likely to feel ostracized? A latent class analysis of personality traits

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    Perceived ostracism (e.g., feeling ignored or excluded) is a painful and distressing experience. However, little empirical research has investigated the types (profiles) of people more likely to perceive ostracism. The present study (N = 395) used latent class analysis to (a) identify potential classes based on the big five personality traits (i.e., openness, agreeableness, negative emotionality, extroversion, and conscientiousness) and (b) examine whether such classes could reliably differentiate levels of self-reported perceived ostracism. We extracted three classes: (a) Moderate Traits (MT), (b) the Quiet Over-Reacting Procrastinators (QORP), and (c) the Active and Adaptable Thinkers (AAT). Those in the QORP class reported the highest levels of perceived ostracism, whereas those in the AAT class reported the lowest levels of perceived ostracism compared to the MT class. This study provides new insight into the profiles of individuals who may be more likely to perceive ostracism. However, further research is needed to explore the association between personality and ostracism (e.g., as ostracism may lead to changes in personality), so that potential risk markers to trigger early psychological interventions of such ostracized individuals can be identified

    Multi-confocal fluorescence correlation spectroscopy in living cells using a complementary metal oxide semiconductor-single photon avalanche diode array

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    International audienceLiving cells are heterogeneous and rapidly changing biological samples. It is thus desirable to measure molecular concentration and dynamics in many locations at the same time. In this note, we present a multi-confocal setup capable of performing simultaneous fluorescence correlation spectroscopy measurements, by focusing the spots with a spatial light modulator and acquiring data with a monolithic 32 × 32 single-photon avalanche photodiode array. A post-processing method is proposed to correct cross-talk effects between neighboring spots. We demonstrate the applicability of our system by simultaneously measuring the diffusion of free enhanced Green Fluorescent Protein (eGFP) molecules at nine different points in living cells

    Monte Carlo radiative transfer for the nebular phase of Type Ia supernovae

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    We extend the range of validity of the ARTIS 3D radiative transfer code up to hundreds of days after explosion, when Type Ia supernovae (SNe Ia) are in their nebular phase. To achieve this, we add a non-local thermodynamic equilibrium population and ionization solver, a new multifrequency radiation field model, and a new atomic data set with forbidden transitions. We treat collisions with non-thermal leptons resulting from nuclear decays to account for their contribution to excitation, ionization, and heating. We validate our method with a variety of tests including comparing our synthetic nebular spectra for the well-known one-dimensional W7 model with the results of other studies. As an illustrative application of the code, we present synthetic nebular spectra for the detonation of a sub-Chandrasekhar white dwarf (WD) in which the possible effects of gravitational settling of 22Ne prior to explosion have been explored. Specifically, we compare synthetic nebular spectra for a 1.06 M☉ WD model obtained when 5.5 Gyr of very efficient settling is assumed to a similar model without settling. We find that this degree of 22Ne settling has only a modest effect on the resulting nebular spectra due to increased 58Ni abundance. Due to the high ionization in sub-Chandrasekhar models, the nebular [Ni II] emission remains negligible, while the [Ni III] line strengths are increased and the overall ionization balance is slightly lowered in the model with 22Ne settling. In common with previous studies of sub-Chandrasekhar models at nebular epochs, these models overproduce [Fe III] emission relative to [Fe II] in comparison to observations of normal SNe Ia

    The Chemistry Mechanism in the Community Earth System Model Version 2 (CESM2)

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    The Community Earth System Model version 2 (CESM2) includes a detailed representation of chemistry throughout the atmosphere in the Community Atmosphere Model with chemistry and Whole Atmosphere Community Climate Model configurations. These model configurations use the Model for Ozone and Related chemical Tracers (MOZART) family of chemical mechanisms, covering the troposphere, stratosphere, mesosphere, and lower thermosphere. The new MOZART tropospheric chemistry scheme (T1) has a number of updates over the previous version (MOZART‐4) in CESM, including improvements to the oxidation of isoprene and terpenes, organic nitrate speciation, and aromatic speciation and oxidation and thus improved representation of ozone and secondary organic aerosol precursors. An evaluation of the present‐day simulations of CESM2 being provided for Climate Model Intercomparison Project round 6 (CMIP6) is presented. These simulations, using the anthropogenic and biomass burning emissions from the inventories specified for CMIP6, as well as online calculation of emissions of biogenic compounds, lightning NO, dust, and sea salt, indicate an underestimate of anthropogenic emissions of a variety of compounds, including carbon monoxide and hydrocarbons. The simulation of surface ozone in the southeast United States is improved over previous model versions, largely due to the improved representation of reactive nitrogen and organic nitrate compounds resulting in a lower ozone production rate than in CESM1 but still overestimates observations in summer. The simulation of tropospheric ozone agrees well with ozonesonde observations in many parts of the globe. The comparison of NOx and PAN to aircraft observations indicates the model simulates the nitrogen budget well

    The treatment of diffuse cutaneous systemic sclerosis with autologous hemopoietic stem cells transplantation (HSCT): our experience on 2 cases

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    Objectives: Autologous hematopoietic stem cell transplantation (HSCT) is a treatment option which may be considered for severe diffuse cutaneous systemic sclerosis (dcSSc) patients not responding to cyclophophamide (CY). We present two cases of dcSSc not responding to CY >10 g who were successfully treated with HSCT. Patients and methods: Two dcSSc patients were unresponsive to monthly i.v. pulse of CYC (0.75 g m2). Both patients had significant reduction of DLCO and mild-moderate pulmonary hypertension and HSCT was considered due to the rapid progression of the disease. Following informed consent and ethics committee approval, HSCT was performed. Mobilisation was performed with CY 4g/m2 and recombinant human granulocyte colony stimulating factor (rHu GCSF) followed by a successful apheresis (CD34+ cells, >7X106). Conditioning regimens were: CY 100mg/kg body weight plus thiotepa 10 mg/ kg in the first patient and CY 200 mg/kg in the second. Both graft products were CD34 selected. No arrythmias occurred during the procedure and no other severe side effects were observed during hospitalisation. Results: Follow up: Patients underwent a monthly follow up with physical examination, pulmonary function tests and echocardiography every 3 months. Chest CT has been performed 6 months post transplantation. The following was observed: skin score (from 40 to 10 for the first patient and from 38 to 12 for the second one), LVEF and pulmonary function remained stable, PAP decreased from 45 mmHg to 35 mmHg and from 40 to 32 mmHg. No late complications or cardiac toxicity was observed. Conclusion: These two dcSSc cases demonstrate that HSCT may be successfully performed without serious side effects in cases in whom despite a cumulative CY dose was ineffective. This suggests an “immunological threshold” effect which may be exploited in other severe, therapy refractory autoimmune cases
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