399 research outputs found

    Ozone generation in a wire-to-cylinder corona discharge ozonizer fed with mixtures of O2 and N2

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    The generation of ozone in a coaxial wire-cylinder corona discharge reactor has been experimentally investigated using variable proportions (5% to 90%) of oxygen in nitrogen. The experiments have been carried out under negative polarity and using different gas flow rates (50 cm3/min to 200 cm3/min). The obtained results show that the corona current exhibits a certain dependence with the percentage of oxygen in the gas mixture, which may influence the rate of ozone production. Moreover, the evaluation of the ozone yield has revealed a non-linear dependence of this magnitude with the concentration of oxygen. The maximum ozone yield was obtained when the percentage of oxygen in the gas mixture was about 70%

    ASPEBI: A MATLAB Tool for Motion Analysis of Non-Specific Low Back Pain Patients

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    Low back pain is one of the most common health issues worldwide, and non-specific low back pain (NLBP), whose causes are unknown, represents 85% of these cases. Hamstring Extension in Bipedal Position (PEBI) is a clinical sign designed to discriminate the cause of the pain of NLBP as of muscular origin due to the stiffness of the hamstring. Currently, PEBI lacks quantitative assessment, which is required to be utilized in primary care. To support the process of getting such information, in this work, we present ASPEBI, a customized MATLAB® app developed to provide researchers and clinicians with a tool for the visualization of the kinematic and spatiotemporal gait parameters of patients examined with PEBI. This objective information is processed from data collected with the Xsens MTw Awinda system, which can be analyzed by the final users. Lastly, this tool is user-friendly with a modular design that allows integration of other physiological technologies to conduct multimodal analysis, and it could be utilized to explore issues related to older populations or populations with neurodegenerative diseases, among others

    Ozone production by corona discharge using a hollow needle-plate electrode system

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    Ozone generation using a hollow needle-to-plate corona reactor has been investigated using both positive and negative polarities and various flow rates. Oxygen could be introduced in the reactor either through the needle electrode or through a port on the lateral wall. This configuration al-lowed studying the effect of the flow direction on ozone production

    Ecosystem services show variable responses to future climate conditions in the Colombian páramos

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    Background: The páramos, the high-elevation ecosystems of the northern Andes, are well-known for their high species richness and provide a variety of ecosystem services to local subsistence-based communities and regional urbanizations. Climate change is expected to negatively affect the provision of these services, but the level of this impact is still unclear. Here we assess future climate change impact on the ecosystem services provided by the critically important páramos of the department of Boyacá in Colombia, of which over 25% of its territory is páramo. Methods: We first performed an extensive literature review to identify useful species of Boyacá, and selected 103 key plant species that, based on their uses, support the provision of ecosystem services in the páramos. We collated occurrence information for each key species and using a Mahalanobis distance approach we applied climate niche modelling for current and future conditions. Results: We show an overall tendency of reduction in area for all ecosystem services under future climate conditions (mostly a loss of 10% but reaching up to a loss of 40%), but we observe also increases, and responses differ in intensity loss. Services such as Food for animals, Material and Medicinal, show a high range of changes that includes both positive and negative outcomes, while for Food for humans the responses are mostly substantially negative. Responses are less extreme than those projected for individual species but are often complex because a given ecosystem service is provided by several species. As the level of functional or ecological redundancy between species is not yet known, there is an urgency to expand our knowledge on páramos ecosystem services for more species. Our results are crucial for decision-makers, social and conservation organizations to support sustainable strategies to monitor and mitigate the potential consequences of climate change for human livelihoods in mountainous settings.publishedVersio

    Association between emergency department length of stay and adverse perioperative outcomes in emergency surgery: A cohort study in two Colombian University hospitals

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    Background: In low- and middle-income countries emergency surgery represents a higher proportion of the total number of surgeries and is associated with greater morbidity/mortality. Study aims were to determine if emergency department length of stay (ED-LOS) was associated with adverse perioperative outcomes and if such association varied across patient's risk categories. Methods: A retrospective cohort study was conducted of adult patients who underwent orthopedic or abdominal emergency surgery at two Colombian University hospitals. The population comprised a mix of a representative sample of eligible cases, with unselected patients (2/3), enriched with a high-risk subset (1/3). ED-LOS was defined as the interval between emergency department arrival and surgery start time. Our primary outcome was an adverse perioperative outcome during hospitalization, which was a composite of in-hospital mortality or severe complications such as major cardiovascular adverse events, infection, renal failure and bleeding. Results: Among 1487 patients analyzed, there were 519 adverse perioperative outcomes including 150 deaths. In the unselected sample (n = 998) 17.9% of patients presented an adverse perioperative outcome with a mortality of 4.9%. The median ED-LOS was 24.6 (IQR 12.5-53.2) hours. ED-LOS was associated with age, comorbidities and known risk factors for 30-day mortality. Patients developing an adverse perioperative outcome started surgery 27.1 h later than their counterparts. Prolonged ED-LOS increased the risk of an adverse perioperative outcome in patients without risk factors (covariate-adjusted OR = 2.52), while having 1-2 or 3+ risk factors was negatively associated (OR = 0.87 and 0.72, respectively, p less than 0.001 for the interaction). Conclusion: Prolonged ED-LOS is associated with increased adverse perioperative outcome for patients without risk factors for mortality, but seems protective and medically justified for more complex cases. © 2019 The Author(s)

    Frecuencia elevada del alelo ε4 del gen de apolipoproteína E en una muestra de pacientes con síndrome Down

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    La enfermedad de Alzheimer es la entidad más frecuente enpacientes con síndrome Down (SD) y a su vez uno de losfactores de riesgo para el desarrollo de esta entidad es lapresencia del alelo ε4 de apolipoproteína E. En el presenteestudio se evaluó el genotipo de apolipoproteína E en ungrupo de pacientes de ambos sexos con síndrome Down.Los resultados muestran que hay una frecuencia aumentadapara el alelo ε4 en esta población cuando se hizo la comparacióncon los valores previamente encontrados para unamuestra de la población del Departamento de Risaralda queno presentaban SD la cual se tomó como control
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