254 research outputs found

    Effect of wetting layers on the strain and electronic structure of InAs self-assembled quantum dots

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    The effect of wetting layers on the strain and electronic structure of InAs self-assembled quantum dots grown on GaAs is investigated with an atomistic valence-force-field model and an empirical tight-binding model. By comparing a dot with and without a wetting layer, we find that the inclusion of the wetting layer weakens the strain inside the dot by only 1% relative change, while it reduces the energy gap between a confined electron and hole level by as much as 10%. The small change in the strain distribution indicates that strain relaxes only little through the thin wetting layer. The large reduction of the energy gap is attributed to the increase of the confining-potential width rather than the change of the potential height. First-order perturbation calculations or, alternatively, the addition of an InAs disk below the quantum dot confirm this conclusion. The effect of the wetting layer on the wave function is qualitatively different for the weakly confined electron state and the strongly confined hole state. The electron wave function shifts from the buffer to the wetting layer, while the hole shifts from the dot to the wetting layer.Comment: 14 pages, 3 figures, and 3 table

    Cross-Lingual Knowledge Transfer for Clinical Phenotyping

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    Clinical phenotyping enables the automatic extraction of clinical conditions from patient records, which can be beneficial to doctors and clinics worldwide. However, current state-of-the-art models are mostly applicable to clinical notes written in English. We therefore investigate cross-lingual knowledge transfer strategies to execute this task for clinics that do not use the English language and have a small amount of in-domain data available. We evaluate these strategies for a Greek and a Spanish clinic leveraging clinical notes from different clinical domains such as cardiology, oncology and the ICU. Our results reveal two strategies that outperform the state-of-the-art: Translation-based methods in combination with domain-specific encoders and cross-lingual encoders plus adapters. We find that these strategies perform especially well for classifying rare phenotypes and we advise on which method to prefer in which situation. Our results show that using multilingual data overall improves clinical phenotyping models and can compensate for data sparseness.Comment: LREC 2022 submmision: January 202

    Probes to the Inferior Planets - a New Dawn for NEO and IEO Detection Technology Demonstration from Heliocentric Orbits Interior to the Earth’s?

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    With the launch of MESSENGER and Venus Express, a new wave of exploration of the inner solar system has begun. Noting the growing number of probes to the inner solar system, it is proposed to connect the expertise of the respective spacecraft teams and the NEO and IEO survey community to best utilize the extended cruise phases and to provide additional data return in support of pure science as well as planetary defence. Several missions to Venus and Mercury are planned to follow in this decade. Increased interest in the inferior planets is accompanied by several missions designed to study the Sun and the interplanetary medium (IPM) from a position near or in Earth orbit, such as the STEREO probes and SDO. These augment established solar observation capabilities at the Sun-Earth L1 Lagrangian point such as the SOHO spacecraft. Thus, three distinct classes of spacecraft operate or observe interior to Earth's orbit. All these spacecraft carry powerful multispectral cameras optimized for their respective primary targets. MESSENGER is scheduled to end its six-year interplanetary cruise in March 2011 to enter Mercury orbit, but a similarly extended cruise with several gravity-assists awaits the European Mercury mission BepiColombo. Unfortunately, the automatic abort of the orbit insertion manoeuvre has also left Akatsuki (a.k.a. Venus Climate Orbiter (VCO), Planet-C) stranded in heliocentric orbit. After an unintended fly-by, the probe will catch up with Venus in approximately six years. Meanwhile, it stays mostly interior to Venus in a planet-leading orbit. In addition to the study of comets and their interaction with the IPM, observations of small bodies akin to those carried out by outer solar system probes are occasionally attempted with the equipment available. The study of structures in the interplanetary dust (IPD) cloud has been a science objective during the cruise phase of the Japanese Venus probe Akatsuki from Earth to Venus. IPD observations in the astronomical H-band (1.65 µm) are supported by its IR2 camera down to 1.5 µW/m2sr in single 2 minute exposures. In the same setting, point sources of 13 mag can be detected. Obviously, a number of large asteroids exceed this threshold. The Earthguard-1 study, completed in 2003 by the DLR Institute of Planetary Research and Kayser-Threde under ESA contract, proposed a dedicated steerable Ø20...35 cm telescope and CCD camera payload on a probe to the inner solar system, to detect Near-Earth and Inner-Earth Objects (NEOs, IEOs) in favourable opposition geometry. A ride-share on a Mercury orbiter and a dedicated low-thrust propulsion spacecraft to a heliocentric 0.5 AU orbit were studied. A similar-sized telescope is presently being developed for the AsteroidFinder satellite of DLR. Therefore, the technical feasibility of a number of asteroid observation scenarios involving spacecraft and targets interior to Earth’s orbit is assessed based on the latest available spacecraft information and asteroid population models. A rough estimate of the required effort in terms of ground-based spacecraft operations and on-board resources is given for selected representative scenarios

    Carbapenem-non-susceptible Enterobacteriaceae in Europe : conclusions from a meeting of national experts

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    The emergence and global spread of carbapenemase-producing Enterobacteriaceae is of great concern to health services worldwide. These bacteria are often resistant to all beta-lactam antibiotics and frequently co-resistant to most other antibiotics, leaving very few treatment options. The epidemiology is compounded by the diversity of carbapenem-hydrolysing enzymes and the ability of their genes to spread between different bacterial species. Difficulties are also encountered by laboratories when trying to detect carbapenemase production during routine diagnostic procedures due to an often heterogeneous expression of resistance. Some of the resistance genes are associated with successful clonal lineages which have a selective advantage in those hospitals where antimicrobial use is high and opportunities for transmission exist; others are more often associated with transmissible plasmids. A genetically distinct strain of Klebsiella pneumoniae sequence type (ST) 258 harbouring the K. Pneumoniae carbapenemases (KPC) has been causing epidemics of national and international proportions. It follows the pathways of patient referrals, causing hospital outbreaks along the way. Simultaneously, diverse strains harbouring New Delhi metallo-beta-lactamase (NDM-1) are repeatedly being imported into Europe, commonly via patients with prior medical exposure in the Indian subcontinent. Since the nature and scale of carbapenem-non-susceptible Entrobacteriaceae as a threat to hospital patients in Europe remains unclear, a consultation of experts from 31 countries set out to identify the gaps in diagnostic and response capacity, to index the magnitude of carbapenem-non-susceptibility across Europe using a novel five-level staging system, and to provide elements of a strategy to combat this public health issue in a concerted manner.peer-reviewe

    Intravenous Immunoglobulin Treatment in a Child with Resistant Atopic Dermatitis

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    In a subgroup of patients suffering from atopic dermatitis (AD), treatment is quite difficult even after taking oral immunosuppressants. High-dose intravenous immunoglobulin (IVIG) treatment has been reported to be beneficial for them in a few uncontrolled trials. Herein we report a case of intractable AD in a 5-year-old girl who had significant clinical improvement after receiving 3 cycles of IVIG treatment (2 g/kg) without notable side effects. Since the first infusion of IVIG, the patient's skin lesions improved steadily and the improvement persisted until the 8-month follow-up. The eczema area and severity index score decreased remarkably, while immunologic parameters did not correlate with clinical improvement. This case suggests that IVIG therapy can be quite effective and safe for children with resistant AD

    Substance Abuse-Related Self-Stigma in Women with Substance Use Disorder and Comorbid Posttraumatic Stress Disorder

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    Background: Self-stigma is a result of internalizing negative stereotypes by the affected person. Research on self-stigma in substance use disorders (SUD) is still scarce, especially regarding the role of childhood trauma and subsequent posttraumatic disorders. Objectives: The present study investigated the progressive model of self-stigma in women with SUD and posttraumatic stress disorder (PTSD), and the predictive value of PTSD severity and childhood trauma experiences on self-stigma. Method: In a cross-sectional study with 343 women with SUD and PTSD, we used the Self-Stigma in Alcohol Dependency Scale, the Childhood Trauma Questionnaire (CTQ), the PTSD Symptom Scale Interview (PSS-I), and to control for SUD severity and depression, the Addiction Severity Index Lite and the Beck Depression Inventory-II. Hierarchical regression analyses were conducted for each stage of self-stigma (aware-agree-apply-harm). Results: The interrelated successive stages of self-stigma were largely confirmed. In the regression models, no significant effects of the PSS-I- and the CTQ-scores were observed at any stage of self-stigma. Agreeing with negative stereotypes was solely predicted by younger age, applying these stereotypes to oneself was higher in women with younger age, higher depression and SUD severity, and suffering from the application (harm) was only predicted by depression. Conclusions: The progressive model of self-stigma could be confirmed in women with SUD and PTSD, but PTSD severity and childhood trauma did not directly affect this process. Self-stigma appears to be related to depression in a stronger way than PTSD is related to women with SUD and PTSD

    Transmission of Staphylococcus aureus between health-care workers, the environment, and patients in an intensive care unit: a longitudinal cohort study based on whole-genome sequencing

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    Background: Health-care workers have been implicated in nosocomial outbreaks of Staphylococcus aureus, but the dearth of evidence from non-outbreak situations means that routine health-care worker screening and S aureus eradication are controversial. We aimed to determine how often S aureus is transmitted from health-care workers or the environment to patients in an intensive care unit (ICU) and a high-dependency unit (HDU) where standard infection control measures were in place. Methods: In this longitudinal cohort study, we systematically sampled health-care workers, the environment, and patients over 14 months at the ICU and HDU of the Royal Sussex County Hospital, Brighton, England. Nasal swabs were taken from health-care workers every 4 weeks, bed spaces were sampled monthly, and screening swabs were obtained from patients at admission to the ICU or HDU, weekly thereafter, and at discharge. Isolates were cultured and their whole genome sequenced, and we used the threshold of 40 single-nucleotide variants (SNVs) or fewer to define subtypes and infer recent transmission. Findings: Between Oct 31, 2011, and Dec 23, 2012, we sampled 198 health-care workers, 40 environmental locations, and 1854 patients; 1819 isolates were sequenced. Median nasal carriage rate of S aureus in health-care workers at 4-weekly timepoints was 36·9% (IQR 35·7–37·3), and 115 (58%) health-care workers had S aureus detected at least once during the study. S aureus was identified in 8–50% of environmental samples. 605 genetically distinct subtypes were identified (median SNV difference 273, IQR 162–399) at a rate of 38 (IQR 34–42) per 4-weekly cycle. Only 25 instances of transmission to patients (seven from health-care workers, two from the environment, and 16 from other patients) were detected. Interpretation: In the presence of standard infection control measures, health-care workers were infrequently sources of transmission to patients. S aureus epidemiology in the ICU and HDU is characterised by continuous ingress of distinct subtypes rather than transmission of genetically related strains. Funding: UK Medical Research Council, Wellcome Trust, Biotechnology and Biological Sciences Research Council, UK National Institute for Health Research, and Public Health England

    ASIME 2018 White Paper. In-Space Utilisation of Asteroids: Asteroid Composition -- Answers to Questions from the Asteroid Miners

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    In keeping with the Luxembourg government's initiative to support the future use of space resources, ASIME 2018 was held in Belval, Luxembourg on April 16-17, 2018. The goal of ASIME 2018: Asteroid Intersections with Mine Engineering, was to focus on asteroid composition for advancing the asteroid in-space resource utilisation domain. What do we know about asteroid composition from remote-sensing observations? What are the potential caveats in the interpretation of Earth-based spectral observations? What are the next steps to improve our knowledge on asteroid composition by means of ground-based and space-based observations and asteroid rendez-vous and sample return missions? How can asteroid mining companies use this knowledge? ASIME 2018 was a two-day workshop of almost 70 scientists and engineers in the context of the engineering needs of space missions with in-space asteroid utilisation. The 21 Questions from the asteroid mining companies were sorted into the four asteroid science themes: 1) Potential Targets, 2) Asteroid-Meteorite Links, 3) In-Situ Measurements and 4) Laboratory Measurements. The Answers to those Questions were provided by the scientists with their conference presentations and collected by A. Graps or edited directly into an open-access collaborative Google document or inserted by A. Graps using additional reference materials. During the ASIME 2018, first day and second day Wrap-Ups, the answers to the questions were discussed further. New readers to the asteroid mining topic may find the Conversation boxes and the Mission Design discussions especially interesting.Comment: Outcome from the ASIME 2018: Asteroid Intersections with Mine Engineering, Luxembourg. April 16-17, 2018. 65 Pages. arXiv admin note: substantial text overlap with arXiv:1612.0070

    MEDBERT.de: A Comprehensive German BERT Model for the Medical Domain

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    This paper presents medBERTde, a pre-trained German BERT model specifically designed for the German medical domain. The model has been trained on a large corpus of 4.7 Million German medical documents and has been shown to achieve new state-of-the-art performance on eight different medical benchmarks covering a wide range of disciplines and medical document types. In addition to evaluating the overall performance of the model, this paper also conducts a more in-depth analysis of its capabilities. We investigate the impact of data deduplication on the model's performance, as well as the potential benefits of using more efficient tokenization methods. Our results indicate that domain-specific models such as medBERTde are particularly useful for longer texts, and that deduplication of training data does not necessarily lead to improved performance. Furthermore, we found that efficient tokenization plays only a minor role in improving model performance, and attribute most of the improved performance to the large amount of training data. To encourage further research, the pre-trained model weights and new benchmarks based on radiological data are made publicly available for use by the scientific community.Comment: Keno K. Bressem and Jens-Michalis Papaioannou and Paul Grundmann contributed equall
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