1,691 research outputs found

    Cerebellar Degeneration as Presenting Symptom of Recurrent Endometrial Stromal Sarcoma with Sex-Cord Elements

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    We report a 66-year-old woman with slowly progressive ataxia due to cerebellar atrophy. Imaging studies revealed multiple lesions in both the lungs and dorsal subpleural space. A biopsy identified the lesions as metastases of a low-grade endometrial stromal sarcoma containing sex-cord elements. The histological appearance was identical to a uterine tumor the patient was treated for with hysterectomy 16 years before. The metastases were removed surgically, and after 3 months ataxia had regressed. We conclude that the presenting cerebellar degeneration in this patient resulted from the metastatic recurrence of the endometrial tumor

    How cognitive heuristics can explain social interactions in spatial movement

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    The movement of pedestrian crowds is a paradigmatic example of collective motion. The precise nature of individual-level behaviours underlying crowd movements has been subject to a lively debate. Here, we propose that pedestrians follow simple heuristics rooted in cognitive psychology, such as ‘stop if another step would lead to a collision’ or ‘follow the person in front’. In other words, our paradigm explicitly models individual-level behaviour as a series of discrete decisions. We show that our cognitive heuristics produce realistic emergent crowd phenomena, such as lane formation and queuing behaviour. Based on our results, we suggest that pedestrians follow different cognitive heuristics that are selected depending on the context. This differs from the widely used approach of capturing changes in behaviour via model parameters and leads to testable hypotheses on changes in crowd behaviour for different motivation levels. For example, we expect that rushed individuals more often evade to the side and thus display distinct emergent queue formations in front of a bottleneck. Our heuristics can be ranked according to the cognitive effort that is required to follow them. Therefore, our model establishes a direct link between behavioural responses and cognitive effort and thus facilitates a novel perspective on collective behaviour

    Boosting the efficiency of transient photoluminescence microscopy using cylindrical lenses

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    Transient Photoluminescence Microscopy (TPLM) allows for the direct visualization of carrier transport in semiconductor materials with sub nanosecond and few nanometer resolution. The technique is based on measuring changes in the spatial distribution of a diffraction limited population of carriers using spatiotemporal detection of the radiative decay of the carriers. The spatial resolution of TPLM is therefore primarily determined by the signal-to-noise-ratio (SNR). Here we present a method using cylindrical lenses to boost the signal acquisition in TPLM experiments. The resulting asymmetric magnification of the photoluminescence emission of the diffraction limited spot can increase the collection efficiency by more than a factor of 10, significantly reducing acquisition times and further boosting spatial resolution.Comment: 12 pages, 5 figures, and supporting informatio

    Boosting the efficiency of transient photoluminescence microscopy using cylindrical lenses

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    Transient Photoluminescence Microscopy (TPLM) allows for the direct visualization of carrier transport in semiconductor materials with sub nanosecond and few nanometer resolution. The technique is based on measuring changes in the spatial distribution of a diffraction limited population of carriers using spatiotemporal detection of the radiative decay of the carriers. The spatial resolution of TPLM is therefore primarily determined by the signal-to-noise-ratio (SNR). Here we present a method using cylindrical lenses to boost the signal acquisition in TPLM experiments. The resulting asymmetric magnification of the photoluminescence emission of the diffraction limited spot can increase the collection efficiency by more than a factor of 10, significantly reducing acquisition times and further boosting spatial resolutionWe acknowledge the support from the “(MAD2D-CM)-UAM” project funded by Comunidad de Madrid, by the Recovery, Transformation and Resilience Plan, and by NextGenerationEU from the European Union, as well as from the Spanish Ministry of Science and Innovation under grant agreement TED2021-131018B-C21 and through the Ramón y Cajal program (F.P. RYC-2017-23253

    The Superposition Principle: A Conceptual Perspective on Pedestrian Stream Simulations

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    Models using a superposition of scalar fields for navigation are prevalent in microscopic pedestrian stream simulations. However, classifications, differences, and similarities of models are not clear at the conceptual level of navigation mechanisms. In this paper, we describe the superposition of scalar fields as an approach to microscopic crowd modelling and corresponding motion schemes. We use this background discussion to focus on the similarities and differences of models, and find that many models make use of similar mechanisms for the navigation of virtual agents. In some cases, the differences between models can be reduced to differences between discretisation schemes. The interpretation of scalar fields varies across models, but most of the time this variation does not have a large impact on simulation outcomes. The conceptual analysis of different models of pedestrian dynamics allows for a better understanding of their capabilities and limitations and may lead to better model development and validation

    Utilization of Wellness Practices For Burnout and Stress During COVID-19 Among an Interdisciplinary Cohort of Emergency Healthcare Workers

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    Introduction: The Coronavirus Disease (COVID-19) introduced additional stress to the baseline occupational stressors of emergency care workers. The objectives of this study were to evaluate perceived stress and burnout and the utilization and perceived benefit of wellness practices among emergency healthcare workers (EHCWs), including: emergency physicians, advanced practice providers (APPs), nurses, and departmental administrative staff during the COVID-19 pandemic. Methods: A cross-sectional 28-item electronic survey of EHCWs at three hospitals in a major United States city was used to measure participants’ utilization and perceived benefit of wellness practices, burnout (2-item measure), overall stress (perceived stress scale), and stress related to COVID-19. Results: The sample consisted of 260 respondents (response rate 44.6%, 583 eligible). Over one-half (56.5%) reported burnout from their job and a majority (58.5%) reported moderate to high stress. Wellness activities including regular exercise and engaging in hobbies were associated with lower reports of burnout. Higher stress levels were reported by participants who had tested positive for COVID-19. Nurses reported the highest rates of burnout overall (80.6%). Females reported higher rates of burnout than males across the cohort (64.5 vs 41.9%, p = 0.001), and female APPs reported significantly higher burnout than did male APPs (69.2 vs 38.5%, p = 0.048). Participants reported donated personal protective equipment (PPE) and meals on shift were extremely helpful. Conclusion: The COVID-19 pandemic was a significant contributor to the stress of EHCWs. Regular engagement in wellness activities was associated with lower rates of burnout. The benefit of engagement in wellness practices, both individual practices and organizational interventions are paramount to mitigate stress and burnout in EHCWs

    Exciton diffusion in two-dimensional metal-halide perovskites

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    Two-dimensional layered perovskites are attracting increasing attention as more robust analogues to the conventional three-dimensional metal-halide perovskites for both light harvesting and light emitting applications. However, the impact of the reduced dimensionality on the optoelectronic properties remains unclear, particularly regarding the spatial dynamics of the excitonic excited state within the two-dimensional plane. Here, we present direct measurements of exciton transport in single-crystalline layered perovskites. Using transient photoluminescence microscopy, we show that excitons undergo an initial fast diffusion through the crystalline plane, followed by a slower subdiffusive regime as excitons get trapped. Interestingly, the early intrinsic diffusivity depends sensitively on the choice of organic spacer. A clear correlation between lattice stiffness and diffusivity is found, suggesting exciton–phonon interactions to be dominant in the spatial dynamics of the excitons in perovskites, consistent with the formation of exciton–polarons. Our findings provide a clear design strategy to optimize exciton transport in these systemsThis work has been supported by the Spanish Ministry of Economy and Competitiveness through The “María de Maeztu” Program for Units of Excellence in R&D (MDM-2014-0377). M.S. acknowledges the financial support of a fellowship from “la Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/IN17/11620040. M.S. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 713673. F.P. acknowledges support from the Spanish Ministry for Science, Innovation, and Universities through the state program (PGC2018-097236-A-I00) and through the Ramón y Cajal program (RYC-2017-23253), as well as the Comunidad de Madrid Talent Program for Experienced Researchers (2016-T1/IND-1209). N.A., M.M. and R. D.B. acknowledges support from the Spanish Ministry of Economy, Industry and Competitiveness through Grant FIS2017-86007-C3-1-P (AEI/FEDER, EU). E.P. acknowledges support from the Spanish Ministry of Economy, Industry and Competitiveness through Grant FIS2016-80434-P (AEI/FEDER, EU), the Ramón y Cajal program (RYC-2011- 09345) and the Comunidad de Madrid through Grant S2018/ NMT-4511 (NMAT2D-CM). S.P. acknowledges financial support by the VILLUM FONDEN via the Centre of Excellence for Dirac Materials (Grant No. 11744

    Clinical effectiveness of hymenoptera venom immunotherapy

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    Treatment failure during venom immunotherapy (VIT) may be associated with a variety of risk factors. Our aim was to evaluate the association of baseline serum tryptase concentration (BTC) and of other parameters with the frequency of VIT failure during the maintenance phase. In this observational prospective multicenter study, we followed 357 patients with established honey bee or vespid venom allergy after the maintenance dose of VIT had been reached. In all patients, VIT effectiveness was either verified by sting challenge (n = 154) or patient self-reporting of the outcome of a field sting (n = 203). Data were collected on BTC, age, gender, preventive use of anti-allergic drugs (oral antihistamines and/or corticosteroids) right after a field sting, venom dose, antihypertensive medication, type of venom, side effects during VIT, severity of index sting reaction preceding VIT, and duration of VIT. Relative rates were calculated with generalized additive models. 22 patients (6.2%) developed generalized symptoms during sting challenge or after a field sting. A strong association between the frequency of VIT failure and BTC could be excluded. Due to wide confidence bands, however, weaker effects (odds ratios <3) of BTC were still possible, and were also suggested by a selective analysis of patients who had a sting challenge. The most important factor associated with VIT failure was a honey bee venom allergy. Preventive use of anti-allergic drugs may be associated with a higher protection rate. It is unlikely that an elevated BTC has a strong negative effect on the rate of treatment failures. The magnitude of the latter, however, may depend on the method of effectiveness assessment. Failure rate is higher in patients suffering from bee venom allergy

    Hubungan Empati Petani Dan Keterampilan Sebagai Fasilitator Di Pusat Pelatihan Pertanian Dan Pedesaan Swadaya Jawa Barat

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    Tujuan penelitian adalah menganalisis hubungan empati petani dan keterampilan sebagai fasilitator pembelajaran bagi para petani di Pusat Pelatihan Pertanian Swadaya (P4S). Jenis penelitian adalah survei dengan melibatkan 140 orang petani fasilitator P4S di 17 kabupaten, Provinsi Jawa Barat sebagai responden. Sebanyak 86,43% responden memiliki empati dalam kategori sedang dan 13,57% berada dalam kategori tinggi. Sebanyak 54,29% responden memiliki keterampilan memfasilitasi berada dalam kategori tinggi dan 45,71% dalam kategori sedang. Analisis korelasional menunjukkan bahwa terdapat hubungan positif yang signifikan antara empati dan keterampilan memfasilitasi (p&lt;0,05) dengan derajat hubungan yang lemah (r=0,02)
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