195 research outputs found
Regresión Logística y Técnicas de Aprendizaje. Aplicaciones.
En este TFG se exponen principalmente dos temas: la Regresión Logística y el Análisis de Conglomerados o Clustering. La regresión logística es explicada teóricamente en el primer capítulo y se ilustra más adelante en el tercer capítulo mediante un ejemplo con un conjunto de datos reales del COVID en Aragón. En el segundo capítulo se introducen las técnicas de aprendizaje supervisado y no supervisado, centrándonos, dentro de estas últimas, en la técnica del análisis de conglomerados. Se explican dos de los algoritmos más importantes dentro del clustering: K-medias y Clustering Jerárquico Aglomerativo. En el tercer capítulo se ilustra la teoría de los dos primeros a través de un conjunto de datos reales del COVID en Aragón proporcionado por las administraciones. <br /
Estudio de las causas de varamiento y muerte de dos cetáceos en las Islas Canarias
Las Islas Canarias albergan una gran variedad de especies de cetáceos, encontrándose 28 registradas. Además, es un lugar donde frecuentemente se producen varamientos de estos animales, tanto activos como pasivos, por diferentes causas. En este trabajo se van a exponer los casos clínicos de dos delfines moteados del Atlántico (Stenella frontalis) varados en las costas canarias a los que se practicó la necropsia, se realizó su posterior análisis histopatológico en el laboratorio y se llegó a determinar las causas de su muerte. En el primer caso se observó una grave obstrucción estomacal debido a un acúmulo de bolsas de plástico y en el segundo se detectó un tumor primario en el neuroectodermo.The Canary Islands shelter a great variety of different species of cetaceans, there being 28 species registered. Also, it is a place where cetacean strandings, both active and passive, take place frequently , by different causes. In this work we are going to expose two clinical cases about stranded cetaceans on the Canary coasts. The necropsy and histopathological analysis at the laboratory determined the causes of death of both animals. In the first case, an important stomach obstruction due to many carrier bags was observed and in the second case a primary tumor in the neuroectoderm was detected
Gamma Irradiation of Magnetoresistive Sensors for Planetary Exploration
A limited number of Anisotropic Magnetoresistive (AMR) commercial-off-the-shelf (COTS) magnetic sensors of the HMC series by Honeywell, with and without integrated front-end electronics, were irradiated with gamma rays up to a total irradiation dose of 200 krad (Si), following the ESCC Basic Specification No. 22900. Due to the magnetic cleanliness required for these tests a special set-up was designed and successfully employed. Several parameters of the sensors were monitored during testing and the results are reported in this paper. The authors conclude that AMR sensors without front-end electronics seem to be robust against radiation doses of up to 200 krad (Si) with a dose rate of 5 krad (Si)/hour and up to a resolution of tens of nT, but sensors with an integrated front-end seem to be more vulnerable to radiation
Estudio de problemas de gestación en <i>chamaeleo calyptratus</i>
Para poder identificar, evaluar y valorar los problemas que aparecen en la reproducción en cautividad de camaleones debemos incluir todos los factores que influyen en el acto reproductivo, analizando las características anatómicas y fisiológicas del aparato reproductor, factores ambientales, factores biológicos y alimentación, y tener en cuenta la gran biodiversidad y especificidad que dentro de la familia Chamaleonidae existe. El diagnóstico se basa principalmente en una anamnesis completa, examen físico exhaustivo, añadiendo pruebas complementarias, principalmente de diagnóstico por imagen, para poder valorar las causas predisponentes y determinantes de fallos en la reproducción. Teniendo en cuenta estos datos y otros sobre el tema se han estudiado y presentado dos casos clínicos de problemas de gestación en dos hembras de Chamaeleo calyptratus, uno de retención preovulatoria (en fase de folículo) y otro de retención postovulatoria (en fase de huevo).In order to identify, evaluate and assess different problems that can appear in chameleons’ reproduction in captivity, we must consider all the factors that are involved in the reproductive act, analyzing reproductive system’s anatomical and physiological characteristics, environmental factors, biological factors and feeding, bearing in mind the great biodiversity and specificity inside the Chamaleonidae family.The diagnosis is mainly based on complete anamnesis, thorough physical exam and complementary tests as diagnostic imaging, to be able to identify any underlying and determinant factors of reproductive failures. Knowing this information, two clinical cases about gestation problems on two Chamaeleo calyptratus females have been, one consisting of preovulatory hold (folicle phase) and the other, postovulatory egg hold (egg phase)
Utilización de derivados de quinazolinas para enfermedades neurodegenerativas
Peer reviewedConsejo Superior de Investigaciones CientíficasT3 Traducción de patente europe
Long photoperiods sustain high pH in Arctic kelp forests
Concern on the impacts of ocean acidification on calcifiers, such as bivalves, sea urchins, and foraminifers, has led to efforts to understand the controls on pH in their habitats, which include kelp forests and seagrass meadows. The metabolism of these habitats can lead to diel fluctuation in pH with increases during the day and declines at night, suggesting no net effect on pH at time scales longer than daily. We examined the capacity of subarctic and Arctic kelps to up-regulate pH in situ and experimentally tested the role of photoperiod in determining the capacity of Arctic macrophytes to up-regulate pH. Field observations at photoperiods of 15 and 24 hours in Greenland combined with experimental manipulations of photoperiod show that photoperiods longer than 21 hours, characteristic of Arctic summers, are conducive to sustained up-regulation of pH by kelp photosynthesis. We report a gradual increase in pH of 0.15 units and a parallel decline in pCO2 of 100 parts per million over a 10-day period in an Arctic kelp forest over midsummer, with ample scope for continued pH increase during the months of continuous daylight. Experimental increase in CO2 concentration further stimulated the capacity of macrophytes to deplete CO2 and increase pH. We conclude that long photoperiods in Arctic summers support sustained up-regulation of pH in kelp forests, with potential benefits for calcifiers, and propose that this mechanism may increase with the projected expansion of Arctic vegetation in response to warming and loss of sea ice.The study was funded by the Danish Environmental Protection Agency within the Danish Cooperation for Environment in the Arctic. It is also a contribution to the Greenland Ecosystem Monitoring program (www.G-E-M.dk) and the Arctic Science Partnership (www.asp-net.org). M.S.-M. was supported by a Fundación “La Caixa” fellowship (Spain). We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe
Episodic Arctic CO2 Limitation in the West Svalbard Shelf
The European Sector of the Arctic Ocean is characterized by low CO2 concentrations in seawater during spring and summer, largely due to strong biological uptake driven by extensive plankton blooms in spring. The spring plankton bloom is eventually terminated by nutrient depletion and grazing. However, low CO2 concentrations in seawater and low atmospheric resupply of CO2 can cause episodes during which the phytoplankton growth is limited by CO2. Here, we show that gross primary production (GPP) of Arctic plankton communities increases from 32 to 72% on average with CO2 additions in spring. Enhanced GPP with CO2 additions occur during episodes of high productivity, low CO2 concentration and in the presence of dissolved inorganic nutrients. However, during summer the addition of CO2 supresses planktonic Arctic GPP. Events of CO2 limitation in spring may contribute to the termination of the Arctic spring plankton blooms. The stimulation of GPP by CO2 during the spring bloom provides a biotic feedback loop that might influence the global role played by the Arctic Ocean as a CO2 sink in the future
Continuous daylight in the high-Arctic summer supports high plankton respiration rates compared to those supported in the dark
Plankton respiration rate is a major component of global CO2 production and is forecasted to increase rapidly in the Arctic with warming. Yet, existing assessments in the Arctic evaluated plankton respiration in the dark. Evidence that plankton respiration may be stimulated in the light is particularly relevant for the high Arctic where plankton communities experience continuous daylight in spring and summer. Here we demonstrate that plankton community respiration evaluated under the continuous daylight conditions present in situ, tends to be higher than that evaluated in the dark. The ratio between community respiration measured in the light (Rlight) and in the dark (Rdark) increased as the 2/3 power of Rlight so that the Rlight:Rdark ratio increased from an average value of 1.37 at the median Rlight measured here (3.62 µmol O2 L-1 d-1) to an average value of 17.56 at the highest Rlight measured here (15.8 µmol O2 L-1 d-1). The role of respiratory processes as a source of CO2 in the Arctic has, therefore, been underestimated and is far more important than previously believed, particularly in the late spring, with 24 h photoperiods, when community respiration rates are highest
Cerebrospinal fluid and plasma small extracellular vesicles and mirnas as biomarkers for prion diseases
Diagnosis of transmissible spongiform encephalopathies (TSEs), or prion diseases, is based on the detection of proteinase K (PK)-resistant PrPSc in post-mortem tissues as indication of infection and disease. Since PrPSc detection is not considered a reliable method for in vivo diagnosis in most TSEs, it is of crucial importance to identify an alternative source of biomarkers to provide useful alternatives for current diagnostic methodology. Ovine scrapie is the prototype of TSEs and has been known for a long time. Using this natural model of TSE, we investigated the presence of PrPSc in exosomes derived from plasma and cerebrospinal fluid (CSF) by protein misfolding cyclic amplification (PMCA) and the levels of candidate microRNAs (miRNAs) by quantitative PCR (qPCR). Significant scrapie-associated increase was found for miR-21-5p in plasma-derived but not in CSF-derived exosomes. However, miR-342-3p, miR-146a-5p, miR-128-3p and miR-21-5p displayed higher levels in total CSF from scrapie-infected sheep. The analysis of overexpressed miRNAs in this biofluid, together with plasma exosomal miR-21-5p, could help in scrapie diagnosis once the presence of the disease is suspected. In addition, we found the presence of PrPSc in most CSF-derived exosomes from clinically affected sheep, which may facilitate in vivo diagnosis of prion diseases, at least during the clinical stage
Benzylamine and Thenylamine Derived Drugs Induce Apoptosis and Reduce Proliferation, Migration and Metastasis Formation in Melanoma Cells
Melanomas are heterogeneous and aggressive tumors, and one of the worse in prognosis. Melanoma subtypes follow distinct pathways until terminal oncogenic transformation. Here, we have evaluated a series of molecules that exhibit potent cytotoxic effects over the murine and human melanoma cell lines B16F10 and MalMe-3M, respectively, both ex vivo and in animals carrying these melanoma cells. Ex vivo mechanistic studies on molecular targets involved in melanoma growth, migration and viability were evaluated in cultured cells treated with these drugs which exhibited potent proapoptotic and cytotoxic effects and reduced cell migration. These drugs altered the Wnt/β-catenin pathway, which is important for the oncogenic phenotype of melanoma cells. In in vivo experiments, male C57BL/6 or nude mice were injected with melanoma cells that rapidly expanded in these animals and, in some cases were able to form metastasis in lungs. Treatment with anti-tumor drugs derived from benzylamine and 2-thiophenemethylamine (F10503LO1 and related compounds) significantly attenuated tumor growth, impaired cell migration, and reduced the metastatic activity. Several protocols of administration were applied, all of them leading to significant reduction in the tumor size and enhanced animal survival. Tumor cells carrying a luciferase transgene allowed a time-dependent study on the progression of the tumor. Molecular analysis of the pathways modified by F10503LO1 and related compounds defined the main relevant targets for tumor regression: the activation of pro-apoptotic and anti-proliferative routes. These data might provide the proof-of-principle and rationale for its further clinical evaluation
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