La función derivada a partir de una visualización de la linealidad local

Las nociones de derivada en un punto y de función derivada entrañan tradicionalmente una dificultad especial para los alumnos. La forma clásica de introducir el concepto de derivada, con la noción de límite en el centro de sus acepciones puntual y funcional, conlleva un alto nivel de complejidad, lo que pudiera explicar el origen de la dificultad mencionada. En este trabajo se presenta el diseño, la implementación y la valoración de una secuencia de actividades didácticas asistidas por computadora, que promueve la construcción de significado en torno a la función derivada, con alumnos del primer curso de Cálculo de la División de Ingeniería de la Universidad de Sonora, buscando constituir una primera introducción al tratamiento posterior a través de límites, desde la noción de linealidad local

An experimental study of fog and cloud computing in CEP-based Real-Time IoT applications

Internet of Things (IoT) has posed new requirements to the underlying processing architecture, specially for real-time applications, such as event-detection services. Complex Event Processing (CEP) engines provide a powerful tool to implement these services. Fog computing has raised as a solution to support IoT real-time applications, in contrast to the Cloud-based approach. This work is aimed at analysing a CEP-based Fog architecture for real-time IoT applications that uses a publish-subscribe protocol. A testbed has been developed with low-cost and local resources to verify the suitability of CEP-engines to low-cost computing resources. To assess performance we have analysed the effectiveness and cost of the proposal in terms of latency and resource usage, respectively. Results show that the fog computing architecture reduces event-detection latencies up to 35%, while the available computing resources are being used more efficiently, when compared to a Cloud deployment. Performance evaluation also identifies the communication between the CEP-engine and the final users as the most time consuming component of latency. Moreover, the latency analysis concludes that the time required by CEP-engine is related to the compute resources, but is nonlinear dependent of the number of things connected

The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245

We present subarcsecond resolution infrared (IR) imaging and mid-IR spectroscopic observations of the Seyfert 1.9 galaxy NGC 2992, obtained with the Gemini North Telescope and the Gran Telescopio CANARIAS (GTC). The N-band image reveals faint extended emission out to ~3 kpc, and the PAH features detected in the GTC/CanariCam 7.5-13 micron spectrum indicate that the bulk of this extended emission is dust heated by star formation. We also report arcsecond resolution MIR and far-IR imaging of the interacting system Arp 245, taken with the Spitzer Space Telescope and the Herschel Space Observatory. Using these data, we obtain nuclear fluxes using different methods and find that we can only recover the nuclear fluxes obtained from the subarcsecond data at 20-25 micron, where the AGN emission dominates. We fitted the nuclear IR spectral energy distribution of NGC 2992, including the GTC/CanariCam nuclear spectrum (~50 pc), with clumpy torus models. We then used the best-fitting torus model to decompose the Spitzer/IRS 5-30 spectrum (~630 pc) in AGN and starburst components, using different starburst templates. We find that, whereas at shorter mid-IR wavelengths the starburst component dominates (64% at 6 micron), the AGN component reaches 90% at 20 micron. We finally obtained dust masses, temperatures and star formation rates for the different components of the Arp 245 system and find similar values for NGC 2992 and NGC 2993. These measurements are within those reported for other interacting systems in the first stages of the interaction.Comment: 20 pages, 12 figures, accepted by MNRA

Determinación de aflatoxinas en maíz y productos derivados por cromatografía líquida de alta resolución

A study is pressented about the extraction and analysis of aflatoxins in contaminated corn and corn products. The extraction is carried out in a single step grounding the sample, packing it in a glass column and pouring choloform through it. On this way high recoveries are obtained. The quantitation is made by reserve phase H.P.L.C. using fluorescence detection of derivatives of the aflatoxins.Se presenta un estudio sobre la extracción de aflatoxinas de maíz y productos derivados contaminados, así como su análisis por cromatografía líquida de alta resolución. La extracción se lleva a cabo en un sólo paso moliendo la muestra, empacándola en una columna y percolando cloroformo a través de ella. En esta forma se logran unos porcentajes de recuperación mucho más altos que por los métodos tradicionales. El análisis se efectuó por cromatografía líquida en fase inversa. y detección por fluorescencia. con formación pre-via de derivados de las aflatoxinas

Los gasterópodos terrestres del Cuaternario Superior de Gran Canaria (Islas Canarias)- Land gastropods of the Upper Quaternary in Gran Canaria (Canary Islands)

Hemos estudiado la estratigrafía, cronología y paleontología de ocho depósitos sedimentarios (siete paleodunas y un derrubio de ladera) del Pleistoceno Superior de la isla de Gran Canaria (Islas Canarias). Las paleodunas se caracterizan por una alternancia de dunas y paleosuelos, que varía entre un ciclo en la Playa de Jinámar, y once en el Lazareto (Gando). La cronología de estos depósitos, obtenida por racemización de aminoácidos sobre ejemplares del género Theba y calibrada con 14C, muestra una edad entre 44,4 Ka a 22,2 Ka. La aminoestratigrafía ha permitido asignar estos depósitos a cuatro aminozonas (AM2 a AM5) de las registradas por Ortiz et al. (2006). Las asociaciones fósiles de gasterópodos terrestres están representadas por 20 especies pertenecientes a 8 familias, con un grado de endemismo del 95%. Los cambios faunísticos detectados, con respecto a la actualidad, se refieren a la extinción del 25 % de las especies del Pleistoceno Superior, y a la disminución de la extensión geográfica de algunas especies como Theba arinagae y T. aff. grasseti. - A stratigraphic, chronological and paleontological study of eight sedimentary deposits (seven palaeodunes and a colluvial slide) in the Upper Pleistocene of Gran Canaria (Canary Islands) has been undertaken. The palaeodunes are characterized by dune-palaeosoil alternation, from an only cycle in Playa de Jinámar to eleven in Lazareto (Gando). The chronology of these deposits, obtained by amino acid racemisation and 14C datations in Theba genus samples, displays an age between 44,4 Ka and 22,2 Ka. The aminostratigraphy study appoints to these sediments belong to four amino zones (AM2 to AM5) reported by Ortiz et al. (2006). The land snail fossil assemblages are represented by 20 species belonging to eight families, with an endemic degree around 95%. The detected fossil fauna changes with regard to present fauna reveal an Upper Pleistocene species extinction at about 25% and geographic extension decreasing of some species as Theba arinagae and T. aff. grasset

Seasonal dynamics of natural Ostreococcus viral infection at the single cell level using VirusFISH

Ostreococcus is a cosmopolitan marine genus of phytoplankton found in mesotrophic and oligotrophic waters, and the smallest free-living eukaryotes known to date, with a cell diameter close to 1 μm. Ostreococcus has been extensively studied as a model system to investigate viral–host dynamics in culture, yet the impact of viruses in naturally occurring populations is largely unknown. Here, we used Virus Fluorescence in situ Hybridization (VirusFISH) to visualize and quantify viral-host dynamics in natural populations of Ostreococcus during a seasonal cycle in the central Cantabrian Sea (Southern Bay of Biscay). Ostreococcus were predominantly found during summer and autumn at surface and 50 m depth, in coastal, mid-shelf and shelf waters, representing up to 21% of the picoeukaryotic communities. Viral infection was only detected in surface waters, and its impact was variable but highest from May to July and November to December, when up to half of the population was infected. Metatranscriptomic data available from the mid-shelf station unveiled that the Ostreococcus population was dominated by the species O. lucimarinus. This work represents a proof of concept that the VirusFISH technique can be used to quantify the impact of viruses on targeted populations of key microbes from complex natural communities.Preprint5,84

Development of a Novel Prediction Model for Red Blood Cell Transfusion Risk in Cardiac Surgery

Background: Cardiac surgery is a complex and invasive procedure that often requires blood transfusions to replace the blood lost during surgery. Blood products are a scarce and expensive resource. Therefore, it is essential to develop a standardized approach to determine the need for blood transfusions in cardiac surgery. The main objective of our study is to develop a simple prediction model for determining the risk of red blood cell transfusion in cardiac surgery. Methods: Retrospective cohorts of adult patients who underwent cardiac surgery between 2017 and 2019 were studied to identify hypothetical predictors of blood transfusion. Finally, a multivariable logistic regression model was developed to predict the risk of transfusion in cardiac surgery using the AUC and the Hosmer–Lemeshow goodness-of-fit test. Results: We included 1234 patients who underwent cardiac surgery. Of the entire cohort, 875 patients underwent a cardiac procedure 69.4% [CI 95% (66.8%; 72.0%)]; 119 patients 9.6% [CI 95% (8.1%; 11.4%)] underwent a combined procedure, and 258 patients 20.9% [CI 95% (18.7; 23.2)] underwent other cardiac procedures. The median perioperative hemoglobin was 13.0 mg/dL IQR (11.7; 14.2). The factors associated with the risk of transfusion were age > 60 years OR 1.37 CI 95% (1.02; 1.83); sex female OR 1.67 CI 95% (1.24; 2.24); BMI > 30 OR 1.46 (1.10; 1.93); perioperative hemoglobin < 14 OR 2.11 to 51.41 and combined surgery OR 3.97 CI 95% (2.19; 7.17). The final model shows an AUC of 80.9% for the transfusion risk prediction [IC 95% (78.5–83.3%)]; p < 0.001]. Conclusions: We have developed a model with good discriminatory ability, which is more parsimonious and efficient than other models

Evaluación de la huella de carbono en el barrio de la viña Lorca por rehabilitación de daños en edificios tras el sismo de 2011.

Evaluación de la huella de carbono en el barrio de la viña Lorca por rehabilitación de daños en edificios tras el sismo de 2011

Probing the Nuclear and Circumnuclear Activity of NGC1365 in the Infrared

We present new far-infrared (70-500micron) Herschel PACS and SPIRE imaging observations as well as new mid-IR Gemini/T-ReCS imaging (8.7 and 18.3micron) and spectroscopy of the inner Lindblad resonance (ILR) region (R<2.5kpc) of the spiral galaxy NGC1365. We complemented these observations with archival Spitzer imaging and spectral mapping observations. The ILR region of NGC1365 contains a Seyfert 1.5 nucleus and a ring of star formation with an approximate diameter of 2kpc. The strong star formation activity in the ring is resolved by the Herschel/PACS imaging data, as well as by the Spitzer 24micron continuum emission, [NeII]12.81micron line emission, and 6.2 and 11.3micron PAH emission. The AGN is the brightest source in the central regions up to lambda~24micron, but it becomes increasingly fainter in the far-infrared when compared to the emission originating in the infrared clusters (or groups of them) located in the ring. We modeled the AGN unresolved infrared emission with the CLUMPY torus models and estimated that the AGN contributes only to a small fraction (~5%) of the infrared emission produced in the inner ~5kpc. We fitted the non-AGN 24-500micron spectral energy distribution of the ILR region and found that the dust temperatures and mass are similar to those of other nuclear and circumnuclear starburst regions. Finally we showed that within the ILR region of NGC1365 most of the on-going star formation activity is taking place in dusty regions as probed by the 24micron emission.Comment: Accepted for publication in MNRA