1,513 research outputs found

    Trends in unsolicited dermatologic opinions: A national survey

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    In dermatology, a particularly common ethical dilemma can arise when the skin lesions of bystanders are inadvertently viewed in public settings. Dermatology is a unique field, where a person’s organ of interest is readily visible to others. When lesions are suspicious for skin disease, unsolicited medical opinions may or may not be given depending on several factors. This study examined the actions and attitudes of dermatologists with different levels of experience through the use of case scenarios with various settings and skin lesions. © 2017, Dermatology Online Journal. All rights reserved

    Exploring alternative purchasing strategies: just-in-time or just enough?

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    What are the prevalent purchasing strategies used by manufacturing firms to purchase components that are critical to the quality of their most important products? This research reports the findings from data on purchasing strategies collected from 248 companies. The data indicate that although firms seem to be moving away from a transaction-based purchasing strategy towards partnership relations necessary for successful just-in-time strategies, firms are likely to embrace one of four hybrid purchasing strategies that on a spectrum would fall somewhere between the two pure strategies. These identified strategies offer purchasing managers viable alternatives to moving directly into a just-in-time environment

    Network-timing-dependent plasticity

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    Bursts of activity in networks of neurons are thought to convey salient information and drive synaptic plasticity. Here we report that network bursts also exert a profound effect on Spike-Timing-Dependent Plasticity (STDP). In acute slices of juvenile rat somatosensory cortex we paired a network burst, which alone induced long-term depression (LTD), with STDP-induced long-term potentiation (LTP) and LTD. We observed that STDP-induced LTP was either unaffected, blocked or flipped into LTD by the network burst, and that STDP-induced LTD was either saturated or flipped into LTP, depending on the relative timing of the network burst with respect to spike coincidences of the STDP event. We hypothesized that network bursts flip STDP-induced LTP to LTD by depleting resources needed for LTP and therefore developed a resource-dependent STDP learning rule. In a model neural network under the influence of the proposed resource-dependent STDP rule, we found that excitatory synaptic coupling was homeostatically regulated to produce power law distributed burst amplitudes reflecting self-organized criticality, a state that ensures optimal information coding

    Unveiling Coordinated Groups Behind White Helmets Disinformation

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    Propaganda, disinformation, manipulation, and polarization are the modern illnesses of a society increasingly dependent on social media as a source of news. In this paper, we explore the disinformation campaign, sponsored by Russia and allies, against the Syria Civil Defense (a.k.a. the White Helmets). We unveil coordinated groups using automatic retweets and content duplication to promote narratives and/or accounts. The results also reveal distinct promoting strategies, ranging from the small groups sharing the exact same text repeatedly, to complex "news website factories" where dozens of accounts synchronously spread the same news from multiple sites.Comment: To be presented at WWW 2020 Workshop on Computational Methods in Online Misbehavior and forthcoming in the Companion Proceedings of the Web Conference 202

    Potential missed opportunities for diagnosis of cryptococcosis and the association with mortality: A cohort study

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    BACKGROUND: Cryptococcosis is one of the most common life-threatening opportunistic mycoses worldwide. Insidious presentation and slow onset of symptoms make it difficult to recognize, complicating the diagnostic process. Delays in diagnosis may lead to increased mortality. We aim to determine the frequency of missed opportunities for diagnosis of cryptococcosis and its effects on mortality. METHODS: To estimate the proportion of individuals with a potentially missed diagnosis for cryptococcosis in hospitalized patients, we conducted a retrospective cohort study using the Healthcare Cost and Utilization Project State Inpatient Databases from 2005 to 2015 from eight states. All hospitalized adult patients diagnosed with cryptococcal infection or cryptococcal meningitis were included. Potentially missed diagnoses were defined as admissions coded for a procedure or diagnosis suggestive of cryptococcosis in the 90-days prior to the initial cryptococcosis admission. Generalized estimating equations models were used to evaluate the association between underlying comorbidities and potential missed diagnosis of cryptococcosis and 90-day all-cause in-hospital mortality. FINDINGS: Of 5,354 patients with cryptococcosis, 2,445 (45·7%) were people living with HIV (PLWH). Among PLWH, 493/2,445 (20·2%) had a potentially missed diagnosis, of which 83/493 (16·8%) died while hospitalized compared with 265/1,952 (13·6%) of those without a potentially missed diagnosis (relative risk [RR] 1·04, 95% CI 0·99-1·09). Among HIV-negative patients, 977/2,909 (33·6%) had a potentially missed diagnosis, of which 236/977 (24·2%) died while hospitalized compared with 298/1,932 (15·4%) of those not missed (RR 1·12, 95% CI 1·07-1·16). INTERPRETATION: Missed opportunities to diagnose cryptococcosis are common despite highly efficacious diagnostic tests and are associated with increased risk of 90-day mortality in HIV-negative patients. A high index of clinical suspicion is paramount to promptly diagnose, treat, and improve cryptococcosis-related mortality. FUNDING: National Center for Advancing Translational Sciences, Washington University Institute of Clinical and Translational Sciences, and the Agency for Healthcare Research and Quality

    Computational reconstitution of spine calcium transients from individual proteins

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    We have built a stochastic model in the program MCell that simulates Ca^(2+) transients in spines from the principal molecular components believed to control Ca^(2+) entry and exit. Proteins, with their kinetic models, are located within two segments of dendrites containing 88 intact spines, centered in a fully reconstructed 6 Ă— 6 Ă— 5 ÎĽm^3 cube of hippocampal neuropil. Protein components include AMPA- and NMDA-type glutamate receptors, L- and R-type voltage-dependent Ca^(2+) channels, Na^+/Ca^(2+) exchangers, plasma membrane Ca^(2+) ATPases, smooth endoplasmic reticulum Ca^(2+) ATPases, immobile Ca2+ buffers, and calbindin. Kinetic models for each protein were taken from published studies of the isolated proteins in vitro. For simulation of electrical stimuli, the time course of voltage changes in the dendritic spine was generated with the desired stimulus in the program NEURON. Voltage-dependent parameters were then continuously re-adjusted during simulations in MCell to reproduce the effects of the stimulus. Nine parameters of the model were optimized within realistic experimental limits by a process that compared results of simulations to published data. We find that simulations in the optimized model reproduce the timing and amplitude of Ca^(2+) transients measured experimentally in intact neurons. Thus, we demonstrate that the characteristics of individual isolated proteins determined in vitro can accurately reproduce the dynamics of experimentally measured Ca^(2+) transients in spines. The model will provide a test bed for exploring the roles of additional proteins that regulate Ca^(2+) influx into spines and for studying the behavior of protein targets in the spine that are regulated by Ca^(2+) influx

    Driving performance in older adults: Current measures, findings, and implications for roadway safety

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    BACKGROUND AND OBJECTIVES: Over 10,000 people a day turn 65 in the United States. For many older adults, driving represents an essential component of independence and is one of the most important factors in overall mobility. Recent survey studies in older adults suggest that up to 60% of older adult drivers with mild cognitive impairment, and up to 30% with dementia, continue to drive. The purpose of this review is to provide a comprehensive and detailed resource on the topics of cognition and driving for clinicians, researchers, and policymakers working on efforts related to older adult drivers. RESEARCH DESIGN AND METHODS: Publications on PubMed and Medline and discussions with experts working in geriatrics, technology, driving policy, psychology, and diverse aspects of driving performance were utilized to inform the current review. RESULTS: Research indicates that there is a complex and inverse correlation between multiple cognitive measures, driving performance, and risky driving behaviors. The fragmented nature of available peer-reviewed literature, and a reliance on correlative data, do not currently allow for the identification of the temporal and reciprocal nature of the interplay between cognition and driving endpoints. DISCUSSION AND IMPLICATIONS: There are currently no widely accepted definitions, conceptual models, or uniform set of analyses for conducting geriatric research that is focused on driving. Establishing conventions for conducting research that harmonizes the fields of geriatrics, cognition, and driving research is critical for the development of the evidence base that will inform clinical practice and road safety policy

    Multi-Parameter Entanglement in Femtosecond Parametric Down-Conversion

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    A theory of spontaneous parametric down-conversion, which gives rise to a quantum state that is entangled in multiple parameters, such as three-dimensional wavevector and polarization, allows us to understand the unusual characteristics of fourth-order quantum interference in many experiments, including ultrafast type-II parametric down-conversion, the specific example illustrated in this paper. The comprehensive approach provided here permits the engineering of quantum states suitable for quantum information schemes and new quantum technologies.Comment: to appear in Physical Review
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