2,142 research outputs found

    Two-stream instability in quasi-one-dimensional Bose-Einstein condensates

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    We apply a kinetic model to predict the existence of an instability mechanism in elongated Bose-Einstein condensates. Our kinetic description, based on the Wigner formalism, is employed to highlight the existence of unstable Bogoliubov waves that may be excited in the counterpropagation configuration. We identify a dimensionless parameter, the Mach number at T=0, that tunes different regimes of stability. We also estimate the magnitude of the main parameters at which two-stream instability is expected to be observed under typical experimental conditions

    Pulmonary Embolism Associated to HIV Infection

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    A presença de anticorpos antifosfolípidos é frequente em doentes com infecção VIH principalmente em fases avançadas da doença. Apesar da elevada prevalência de anticorpos antifosfolípidos, a sua associação a fenómenos trombóticos é rara, estando apenas descritos alguns casos. Os autores apresentam um caso clínico cuja manifestação inaugural de uma infecção VIH foi um tromboembolismo pulmonar associado á presença de anticoagulante lúpico

    Diffusion behavior of water confined in deformed carbon nanotubes

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    We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7) nanotubes associated with a change from a high to low mobility regimes. The water which in the undeformed (9,9) nanotubes is frozen, becomes liquid for the distortion above a certain threshold. These water diffusion enhancement (suppresion) is related to a reduction (increase) in the number of hydrogen bonds. This suggests that the shape of the nanotube is a particularly important ingredient when considering the dynamical and structural properties of confined water.Comment: 16 pages, 9 figure

    Development and validation of a pragmatic natural language processing approach to identifying falls in older adults in the emergency department

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    BACKGROUND: Falls among older adults are both a common reason for presentation to the emergency department, and a major source of morbidity and mortality. It is critical to identify fall patients quickly and reliably during, and immediately after, emergency department encounters in order to deliver appropriate care and referrals. Unfortunately, falls are difficult to identify without manual chart review, a time intensive process infeasible for many applications including surveillance and quality reporting. Here we describe a pragmatic NLP approach to automating fall identification. METHODS: In this single center retrospective review, 500 emergency department provider notes from older adult patients (age 65 and older) were randomly selected for analysis. A simple, rules-based NLP algorithm for fall identification was developed and evaluated on a development set of 1084 notes, then compared with identification by consensus of trained abstractors blinded to NLP results. RESULTS: The NLP pipeline demonstrated a recall (sensitivity) of 95.8%, specificity of 97.4%, precision of 92.0%, and F1 score of 0.939 for identifying fall events within emergency physician visit notes, as compared to gold standard manual abstraction by human coders. CONCLUSIONS: Our pragmatic NLP algorithm was able to identify falls in ED notes with excellent precision and recall, comparable to that of more labor-intensive manual abstraction. This finding offers promise not just for improving research methods, but as a potential for identifying patients for targeted interventions, quality measure development and epidemiologic surveillance

    Evaluation of Microencapsulation of The UFV-AREG1 Bacteriophage in Alginate-Ca Microcapsules using Microfluidic Devices

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    The indiscriminate use of antibiotics and the emergence of resistant microorganisms have become a major challenge for the food industry. The purpose of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium alginate matrix using microfluidic devices and to study the viability and efficiency of retention. The microcapsules were added to gel of propylene glycol for use as an antimicrobial in the food industry. The technique showed the number of the phage encapsulation, yielding drops with an average 100-250 μ\mum of diameter, 82.1 ±\pm 2% retention efficiency and stability in the gel matrix for 21 days. The gel added to the microencapsulated phage showed efficiency (not detectable on the surface) in reducing bacterial contamination on the surface at a similar level to antimicrobial chemicals (alcohol 70%). Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca and apply the microcapsules in gels for use as sanitizers in the food industry.Comment: 8 pages, 5 figure
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