160 research outputs found
MiniAnDE: a reduced AnDE ensemble to deal with microarray data
This article focuses on the supervised classification of datasets with a
large number of variables and a small number of instances. This is the case,
for example, for microarray data sets commonly used in bioinformatics. Complex
classifiers that require estimating statistics over many variables are not
suitable for this type of data. Probabilistic classifiers with low-order
probability tables, e.g. NB and AODE, are good alternatives for dealing with
this type of data. AODE usually improves NB in accuracy, but suffers from high
spatial complexity since models, each with variables, are included in
the AODE ensemble. In this paper, we propose MiniAnDE, an algorithm that
includes only a small number of heterogeneous base classifiers in the ensemble,
i.e., each model only includes a different subset of the predictive
variables. Experimental evaluation shows that using MiniAnDE classifiers on
microarray data is feasible and outperforms NB and other ensembles such as
bagging and random forest
DISPAR: A tool to model bottom trawl fishing gears
Marine Technology Workshop (Martech05), 17-18 November 2005, Vilanova i la Geltrú, Barcelona.-- 1 pageBottom trawl fishing is a relevant extractive economic activity. However, the limitation of resources and the impact on the environment demand for a more rational exploitation in order to render the activity sustainable and productive in a near future. To this purpose it is important to understand and to analyze the behaviour of fishinggears. DISPAR is a collaboration project betweenthe UPC-CTVG and the CSIC aimed to movetowards this direction. [...]Peer Reviewe
Method for Isolation of Myxozoan proliferative stages from fish at high yield and purity: An essential prerequisite for in vitro, in vivo and genomics-based research developments.
Myxozoans are a diverse group of microscopic cnidarian parasites and some representatives are associated with important diseases in fish, in both marine and freshwater aquaculture systems. Research on myxozoans has been largely hampered by the inability to isolate myxozoan parasites from their host tissues. In this study, we developed and optimized a method to isolate the myxozoan proliferative stages of different size and cellularity from fish blood, using DEAE-cellulose ion exchange chromatography. We optimized several parameters and obtained 99–100% parasite purity, as well as high survival and infectivity. Using polyclonal pan-carp blood cell-specific antibodies, we further developed a rapid cytometric assay for quantification of the proliferative stages, not only in highly concentrated DEAE-C isolates but also in dilute conditions in full blood. Early developmental stages of myxozoans are key to parasite proliferation, establishment, and pathology in their hosts. The isolation of these stages not only opens new possibilities for in vivo and in vitro studies, but also for obtaining purified DNA and protein extracts for downstream analyses. Hence, we provide a long-desired tool that will advance the functional research into the mechanisms of host exploitation and immune stimulation/evasion in this group, which could contribute greatly to the development of therapeutic strategies against myxozoans
Methylene blue? Therapeutic alternative in the management of septic shock refractory to norepinephrine
Introduction: Methylene blue is receiving special interest in perioperative and intensive care of patients with distributive shock due to its ability to block the action of nitric oxide and to antagonize deep vasodilation.
Objective: The objective is to illustrate the use of the methylene blue, summarizing the perioperative management of a case with secondary vasoplegic syndrome due to a norepinephrine refractory septic shock and the response to methylene blue, reviewing the latest evidence of this therapeutic alternative. In practice:We describe the case of a 60-year-old man, paraplegic, with septic shock due to a long evolution decubitus pressure ulcer. After two hours of surgery, the patient remained with hemodynamic deterioration despite high doses of vasopressin (3 IU/hour) and norepinephrine (2 µg/kg /min), therefore methylene blue was administered with two intravenous bolus doses of 50 mg without adverse effects. After half an hour hemodynamic improvement was evidenced, allowing to decrease norepinephrine infusion and normalizing blood pressure. Finally, debridement of necrotic tissue, amputation and disarticulation of left coxofemoral joint was performed with subsequent transfer to the ICU and discharge to the spinal cord injury ward twenty eight days later.
Conclusions: As it has been demonstrated in our patient, methylene blue is a therapeutic alternative to manage patients with persistent hypotension despite the use of various vasopressors during the management of vasoplegic syndrome secondary to septic shock
Tiempos y rendimientos del método de resinación mediante pica tradicional ascendente
Se analizan los tiempos y rendimientos de los trabajos de resinación con el sistema de pica tradicional ascendent
Experimental study of subwavelength grating bimodal waveguides as ultrasensitive interferometric sensors
[EN] Over the recent years, subwavelength grating (SWG) structures have increasingly attracted attention in the area of evanescent-field photonic sensors. In this Letter, for the first time
to the best of our knowledge, we demonstrate experimentally
the real-time refractive index (RI) sensing using the SWG
bimodal interferometric structures. Two different configurations are considered to compare the effect of the nonlinear
phase shift, obtained between the two first transverse electromagnetic propagating modes, in the measured bulk sensitivity. Very high experimental values up to 2270 nm/RIU are
reached, which perfectly match the numerical simulations
and significantly enhance other existing SWG and spectralbased sensors. By measuring the spectral shift, the obtained
experimental sensitivity does not depend on the sensor
length. As a result, a highly sensitive and compact singlechannel interferometer is experimentally validated for refractive index sensing, thus opening new paths in the field of
optical integrated sensors.European Commission (PHC-634013 PHOCNOSIS project); Spanish Government (TEC2015-63838-C3-1-R-OPTONANOSENS project); Universitat Politecnica de Valencia (grant PAID 01-18).Torrijos-Morán, L.; Griol Barres, A.; García-Rupérez, J. (2019). Experimental study of subwavelength grating bimodal waveguides as ultrasensitive interferometric sensors. Optics Letters. 44(19):4702-4705. https://doi.org/10.1364/OL.44.004702S470247054419Cheben, P., Xu, D.-X., Janz, S., & Densmore, A. (2006). Subwavelength waveguide grating for mode conversion and light coupling in integrated optics. Optics Express, 14(11), 4695. doi:10.1364/oe.14.004695Schmid, J. H., Cheben, P., Janz, S., Lapointe, J., Post, E., & Xu, D.-X. (2007). Gradient-index antireflective subwavelength structures for planar waveguide facets. Optics Letters, 32(13), 1794. doi:10.1364/ol.32.001794Bock, P. J., Cheben, P., Schmid, J. H., Lapointe, J., Delâge, A., Janz, S., … Hall, T. J. (2010). Subwavelength grating periodic structures in silicon-on-insulator: a new type of microphotonic waveguide. Optics Express, 18(19), 20251. doi:10.1364/oe.18.020251Halir, R., Bock, P. J., Cheben, P., Ortega‐Moñux, A., Alonso‐Ramos, C., Schmid, J. H., … Janz, S. (2014). Waveguide sub‐wavelength structures: a review of principles and applications. Laser & Photonics Reviews, 9(1), 25-49. doi:10.1002/lpor.201400083Cheben, P., Halir, R., Schmid, J. H., Atwater, H. A., & Smith, D. R. (2018). Subwavelength integrated photonics. Nature, 560(7720), 565-572. doi:10.1038/s41586-018-0421-7Gonzalo Wangüemert-Pérez, J., Cheben, P., Ortega-Moñux, A., Alonso-Ramos, C., Pérez-Galacho, D., Halir, R., … Schmid, J. H. (2014). Evanescent field waveguide sensing with subwavelength grating structures in silicon-on-insulator. Optics Letters, 39(15), 4442. doi:10.1364/ol.39.004442Donzella, V., Sherwali, A., Flueckiger, J., Grist, S. M., Fard, S. T., & Chrostowski, L. (2015). Design and fabrication of SOI micro-ring resonators based on sub-wavelength grating waveguides. Optics Express, 23(4), 4791. doi:10.1364/oe.23.004791Flueckiger, J., Schmidt, S., Donzella, V., Sherwali, A., Ratner, D. M., Chrostowski, L., & Cheung, K. C. (2016). Sub-wavelength grating for enhanced ring resonator biosensor. Optics Express, 24(14), 15672. doi:10.1364/oe.24.015672Yan, H., Huang, L., Xu, X., Chakravarty, S., Tang, N., Tian, H., & Chen, R. T. (2016). Unique surface sensing property and enhanced sensitivity in microring resonator biosensors based on subwavelength grating waveguides. Optics Express, 24(26), 29724. doi:10.1364/oe.24.029724Huang, L., Yan, H., Xu, X., Chakravarty, S., Tang, N., Tian, H., & Chen, R. T. (2017). Improving the detection limit for on-chip photonic sensors based on subwavelength grating racetrack resonators. Optics Express, 25(9), 10527. doi:10.1364/oe.25.010527Benedikovic, D., Berciano, M., Alonso-Ramos, C., Le Roux, X., Cassan, E., Marris-Morini, D., & Vivien, L. (2017). Dispersion control of silicon nanophotonic waveguides using sub-wavelength grating metamaterials in near- and mid-IR wavelengths. Optics Express, 25(16), 19468. doi:10.1364/oe.25.019468Halir, R., Cheben, P., Luque‐González, J. M., Sarmiento‐Merenguel, J. D., Schmid, J. H., Wangüemert‐Pérez, G., … Molina‐Fernández, Í. (2016). Ultra‐broadband nanophotonic beamsplitter using an anisotropic sub‐wavelength metamaterial. Laser & Photonics Reviews, 10(6), 1039-1046. doi:10.1002/lpor.201600213Luque-González, J. M., Herrero-Bermello, A., Ortega-Moñux, A., Molina-Fernández, Í., Velasco, A. V., Cheben, P., … Halir, R. (2018). Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides. Optics Letters, 43(19), 4691. doi:10.1364/ol.43.004691Jahani, S., Kim, S., Atkinson, J., Wirth, J. C., Kalhor, F., Noman, A. A., … Jacob, Z. (2018). Controlling evanescent waves using silicon photonic all-dielectric metamaterials for dense integration. Nature Communications, 9(1). doi:10.1038/s41467-018-04276-8Torrijos-Morán, L., & García-Rupérez, J. (2019). Single-channel bimodal interferometric sensor using subwavelength structures. Optics Express, 27(6), 8168. doi:10.1364/oe.27.008168Levy, R., & Ruschin, S. (2009). Design of a Single-Channel Modal Interferometer Waveguide Sensor. IEEE Sensors Journal, 9(2), 146-1. doi:10.1109/jsen.2008.2011075Zinoviev, K. E., Gonzalez-Guerrero, A. B., Dominguez, C., & Lechuga, L. M. (2011). Integrated Bimodal Waveguide Interferometric Biosensor for Label-Free Analysis. Journal of Lightwave Technology, 29(13), 1926-1930. doi:10.1109/jlt.2011.2150734Kozma, P., Kehl, F., Ehrentreich-Förster, E., Stamm, C., & Bier, F. F. (2014). Integrated planar optical waveguide interferometer biosensors: A comparative review. Biosensors and Bioelectronics, 58, 287-307. doi:10.1016/j.bios.2014.02.049Levy, R., & Ruschin, S. (2008). Critical sensitivity in hetero-modal interferometric sensor using spectral interrogation. Optics Express, 16(25), 20516. doi:10.1364/oe.16.020516García-Rupérez, J., Toccafondo, V., Bañuls, M. J., Castelló, J. G., Griol, A., Peransi-Llopis, S., & Maquieira, Á. (2010). Label-free antibody detection using band edge fringes in SOI planar photonic crystal waveguides in the slow-light regime. Optics Express, 18(23), 24276. doi:10.1364/oe.18.024276Zhang, W., Serna, S., Le Roux, X., Vivien, L., & Cassan, E. (2016). Highly sensitive refractive index sensing by fast detuning the critical coupling condition of slot waveguide ring resonators. Optics Letters, 41(3), 532. doi:10.1364/ol.41.000532Di Falco, A., O’Faolain, L., & Krauss, T. F. (2009). Chemical sensing in slotted photonic crystal heterostructure cavities. Applied Physics Letters, 94(6), 063503. doi:10.1063/1.3079671Molina-Fernández, Í., Leuermann, J., Ortega-Moñux, A., Wangüemert-Pérez, J. G., & Halir, R. (2019). Fundamental limit of detection of photonic biosensors with coherent phase read-out. Optics Express, 27(9), 12616. doi:10.1364/oe.27.01261
Relaciones ε–NTU para intercambiadores de placas con múltiples pasos y número reducido de placas
Los intercambiadores de placas presentan varias ventajas: alta compacidad, bajo ensuciamiento, altos
coeficientes de transferencia de calor y alta flexibilidad. Dentro de esta última ventaja, destaca su
capacidad para poder adaptar flujos con grandes diferencias de capacidades caloríficas y/o pérdidas de
carga admisibles mediante configuraciones donde uno de los fluidos (el de mayor caudal o calor
específico y/o menor pérdida de carga) debe realizar múltiples pasos en el intercambiador para
acomodar la pérdida de carga admisible o para aumentar el coeficiente global de transferencia de
calor.
Cuando uno de los fluidos realiza varios pasos, el intercambiador se puede analizar como una serie de
intercambiadores de flujo en contracorriente y de flujo paralelo alternos. Desde este punto de vista,
Kandilkar y Shah [1,2] obtuvieron relaciones entre la eficiencia térmica P1=ΔT1/(Tce-Tfe) y
NTU1=UA/C1 y la relación de capacidades caloríficas R1=C1/C2. Este método presenta un
inconveniente de cara al cálculo de un intercambiador con herramientas informáticas, ya que existen
diferentes expresiones en función del número de pasos del intercambiador. Además, para un número
reducido de placas, la solución propuesta se presenta en forma de tablas y no de ecuaciones
algebraicas.
En este trabajo se obtiene la expresión algebraica de un intercambiador de placas en configuración 1
paso – N pasos mediante el método ε-NTU, dónde el parámetro NTU se define con la capacidad
calorífica mínima, lo que lo hace más adecuado para los cálculos. Además se presenta una corrección
de la solución analítica, en función del número de placas, para un número de placas reducido en
diferentes configuraciones
Contribución de las fibras a la resistencia al corte en elementos de hormigón armado en flexión
La incorporación de fibras al hormigón mejora el comportamiento al corte permitiendo reemplazar parcial o totalmente el refuerzo transversal; en ocasiones el modo de falla puede variar de corte (frágil) a flexión (dúctil). Ante la escasa información acerca del comportamiento al corte de vigas de hormigón armado reforzadas con fibras afectadas por procesos de degradación, se inició un estudio incluyendo vigas dañadas por reacción álcalis-sílice y probetas sanas. Este trabajo presenta los primeros resultados sobre hormigones sin dañar que muestran la contribución de las fibras. Se fabricaron vigas con barras de acero convencionales como refuerzo principal de flexión, incorporando macrofibras de acero o poliméricas; y como referencia elementos similares sin fibras. Las vigas fueron cargadas hasta la falla por corte, registrando la respuesta carga-deformación y el patrón de fisuración. Vigas semejantes con agregados reactivos y contenidos elevados de álcalis para propiciar el daño, constituyen la segunda parte del proyecto
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