786 research outputs found

    Introducing fractal dimension algorithms to calculate the Hurst exponent of financial time series

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    In this paper, three new algorithms are introduced in order to explore long memory in financial time series. They are based on a new concept of fractal dimension of a curve. A mathematical support is provided for each algorithm and its accuracy is tested for different length time series by Monte Carlo simulations. In particular, in the case of short length series, the introduced algorithms perform much better than the classical methods. Finally, an empirical application for some stock market indexes as well as some individual stocks is presented

    Iridium-Promoted B-B Bond Activation: Preparation and X-ray Diffraction Analysis of a mer-Tris(boryl) Complex

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    The tris(boryl) complex Ir(Bcat)3{¿3-P,O,P-[xant(PiPr2)2]} has been prepared. Its X-ray diffraction analysis structure reveals that the boryl groups are disposed in a mer rearrangement despite of the very strong trans influence of the boryl ligands. An energy decomposition analysis method coupled to natural orbitals for chemical valence suggests that the p-backdonation from the metal to the pz atomic orbital of the boron atom decreases about 43% in the Ir-B bonds disposed mutually trans with regard to the other one

    Some histopathological and clinical correlations in oral squamous cell carcinoma

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    Oral squamous cell carcinoma (SCC) is an important health problem that causes high mortality and morbidity. Correlations between some clinical and histopathological parameters were studied in 37 oral SCC. Some interesting aspects in oral SCC arising from precancerous lesions were found such as smaller size and a lower TNM stage at the moment of diagnosis. Histological and clinical differences were also found between tumors invading deep tissues by little groups of dissociated malignant cells and those invading by big masses of malignant cells. The possible significance of the intensity of peritumoral eosinophilic infiltrate was also studied.Le carcinome squameux de la cavité orale constitue un problème important de santé, qui est responsable d’une mortalité et d’une morbidité élevées. Nous avons étudié 37 carcinomes squameux de la cavité orale à travers un suivi clinique et une étude des corrélations entre les variables cliniques et histopathologiques. Nous avons relevé différents aspects intéressants en ce qui concerne les carcinomes squameux de la cavité orale qui procédaient de lésions précancéreuses comme leur petite dimention et le bas stade TNM au moment du diagnostic. Nous avons également trouvé des différences cliniques et histopathologiques entre les tumeurs qui envahissent les tissus adjecents en petits groupes et ceux qui le font en grandes masses de cellules malignes. Finalement, nous avons étudié la signification possible de l’intensité de l’infiltrat à eosinophiles peritumoral

    Resistance of Leishmania (Viannia) Panamensis to Meglumine Antimoniate or Miltefosine Modulates Neutrophil Effector Functions.

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    Leishmania (Viannia) panamensis (L. (V.) p.) is the main causative agent of cutaneous leishmaniasis in Colombia and is usually treated with either meglumine antimoniate (MA) or miltefosine (MIL). In recent years, there has been increasing evidence of the emergence of drug-resistance against these compounds. Neutrophils are known to play an important role in immunity against Leishmania. These cells are rapidly recruited upon infection and are also present in chronic lesions. However, their involvement in the outcome of infection with drug-resistant Leishmania has not been examined. In this study, human and murine neutrophils were infected in vitro with MA or MIL drug-resistant L. (V.) p. lines derived from a parental L. (V.) p. drug-susceptible strain. Neutrophil effector functions were assessed analyzing the production of reactive oxygen species (ROS), the formation of neutrophil extracellular trap (NET) and the expression of cell surface activation markers. Parasite killing by neutrophils was assessed using L. (V.) p. transfected with a luciferase reporter. We show here that MA and MIL-resistant L. (V.) p. lines elicited significantly increased NET formation and MA-resistant L. (V.) p. induced significantly increased ROS production in both murine and human neutrophils, compared to infections with the parental MIL and MA susceptible strain. Furthermore, neutrophils exposed to drug-resistant lines showed increased activation, as revealed by decreased expression of CD62L and increased expression of CD66b in human neutrophils yet presented higher survival within neutrophils than the drug-susceptible strain. These results provide evidence that parasite drug-susceptibility may influences neutrophil activation and function as well as parasite survival within neutrophils. Further investigaton of the inter-relationship of drug susceptibility and neutrophil effector function should contribute to better understanding of the factors involved in susceptibility to anti-Leishmania drugs

    BIOMASA E ÍNDICE DE ÁREA FOLIAR DE ROSMARINUS OFFICINALIS L. EN MATORRAL SEMIARIDO (CUENCA DE MULA, MURCIA)

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    Several parameters (above ground biomass and Leaf Area Index) of Rosmarinus officinalis L., one of the most representative species of the Mediterranean matorral, has been studied in the El Ardal Experimental Field, under the MEDALUS (Mediterranean Desertification and Land Use) project, from the European Community. Allometric relationships between above-ground biomass and biovolume, which have been used to estimate average biomass in the matorral. Leaf Area Index has been calculated using leaf weight/leaf area and leaf weight/total weight relationships. Results show values (836.2 g.m-2 of biomass) far from the general range raported in othe semi-arid Mediterranean scrublands, what might be partially explained by the existence of hydric compensation mechanisms.Se han estudiado diversos parámetros (biomasa e índice de área foliar) de Rosmarinus officinalis L., una de las especies más representativas del matorral mediterráneo, en el Campo Experimental de El Ardal (Cuenca de Mula, Murcia) dentro del marco del Proyecto MEDALUS (Mediterranean Desertification and Land Use), de la Comunidad Europea. Se han establecido relaciones alométricas entre la biomasa y el biovolumen que, posteriormente, han sido utilizadas en la estimación de la biomasa media del matorral. Se ha calculado el índice foliar a partir de las relaciones peso/área foliar y peso foliar/peso total. Los resultados (836.2 g.m-2 de biomasa) muestran valores alejados del rango general aportado para otros matorrales semiáridos, hecho que podría estar parcialmente explicado por la existencia de diversos mecanismos de compensación hídrica

    Quality of education and university workspaces

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    La sociedad actual avanza a pasos agigantados, circunstancia que exige de nuestro modelo educativo un cambio paralelo a dichos avances. La educación es uno de los motores de cambio y como tal debe dar respuesta a las exigencias que se le planteen. Es mucha la bibliografía que podemos encontrar acerca de la calidad educativa, pero muy poca de ésta se centra en la evaluación de la calidad de los espacios educativos como tales. Desde este estudio se pretende analizar los puntos de vista y exigencias de los estudiantes de la Facultad de Ciencias de la Educación de la Universidad de Granada respecto a dichos espacios educativos.Today's society is moving forward at a rapid pace, a fact that requires that our educational model change in parallel with such developments. Education is one of the drivers of change and as such must respond to the demands made on it. There is ample literature about the quality of education, but very little of it focuses on assessing the quality of educational spaces as such. The aim of this study is to examine the views and needs of students at the Faculty of Education at the University of Granada with respect to such educational spaces.Departamento de Psicología Socia

    A framework for modelling the biomechanical behaviour of the human liver during breathing in real time using machine learning

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    Progress in biomechanical modelling of human soft tissue is the basis for the development of new clinical applications capable of improving the diagnosis and treatment of some diseases (e.g. cancer), as well as the surgical planning and guidance of some interventions. The finite element method (FEM) is one of the most popular techniques used to predict the deformation of the human soft tissue due to its high accuracy. However, FEM has an associated high computational cost, which makes it difficult its integration in real-time computer-aided surgery systems. An alternative for simulating the mechanical behaviour of human organs in real time comes from the use of machine learning (ML) techniques, which are much faster than FEM. This paper assesses the feasibility of ML methods for modelling the biomechanical behaviour of the human liver during the breathing process, which is crucial for guiding surgeons during interventions where it is critical to track this deformation (e.g. some specific kind of biopsies) or for the accurate application of radiotherapy dose to liver tumours. For this purpose, different ML regression models were investigated, including three tree-based methods (decision trees, random forests and extremely randomised trees) and other two simpler regression techniques (dummy model and linear regression). In order to build and validate the ML models, a labelled data set was constructed from modelling the deformation of eight ex-vivo human livers using FEM. The best prediction performance was obtained using extremely randomised trees, with a mean error of 0.07 mm and all the samples with an error under 1 mm. The achieved results lay the foundation for the future development of some real-time software capable of simulating the human liver deformation during the breathing process during clinical interventions.This work has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) through research projects TIN2014-52033-R and DPI2013-40859-R, both also supported by European FEDER funds. The authors acknowledge the kind collaboration of the personnel from the hospital involved in the research.Lorente, D.; Martínez-Martínez, F.; Rupérez Moreno, MJ.; Lago, MA.; Martínez-Sober, M.; Escandell-Montero, P.; Martínez-Martínez, JM.... (2017). A framework for modelling the biomechanical behaviour of the human liver during breathing in real time using machine learning. Expert Systems with Applications. 71:342-357. doi:10.1016/j.eswa.2016.11.037S3423577

    ACORDE a Cosmic Ray Detector for ALICE

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    ACORDE is one of the ALICE detectors, presently under construction at CERN. It consists of an array of plastic scintillator counters placed on the three upper faces of the ALICE magnet. It will act as a cosmic ray trigger, and, together with other ALICE sub-detectors, will provide precise information on cosmic rays with primary energies around 1015÷101710^{15} \div 10^{-17} eV. Here we describe the design review of ACORDE along with the present status and integration into ALICE.Comment: 2 pages, 2 figures. Conference Proceeding of the X Pisa Meeting on Advanced Detectors, to be published in a special issue of Nuclear Instruments and Method

    Relationship Between Glucocerebrosidase Activity and Clinical Response to Enzyme Replacement Therapy in Patients With Gaucher Disease Type I

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    The quantification of enzyme activity in the patient treated with enzyme replacement therapy (ERT) has been suggested as a tool for dosage individualization, so we conducted a study to evaluate the relationship between glucocerebrosidase activity and clinical response in patients with Gaucher disease type I (GD1) to ERT. The study included patients diagnosed with GD1, who were being treated with ERT, and healthy individuals. Markers based on glucocerebrosidase activity measurement in patients’ leucocytes were studied: enzyme activity at 15 min. post-infusion (Act75) reflects the amount of enzyme that is distributed in the body post-ERT infusion, and accumulated glucocerebrosidase activity during ERT infusion (Act75-0) indicates the total drug exposure during infusion. The clinical response was evaluated based on criteria established by Pastores et al. and Gaucher Severity Score Index. Statistical analysis included ROC analysis and area under the curve test. Act75 and Act75-0 were found to be moderate predictive markers of an optimal clinical response (area under the ROC of Act75 was 0.733 and Act75-0 was 0.817). Act75-0 showed statistical significance in its discriminative capacity (p < 0.05) for obtaining an optimal response to ERT. The cut-off point was 58% (RR = 1.800; 95% CI: 1.003–3.229; p < 0.05). Moreover, Act75 showed a significant and inverse correlation with the Gaucher Severity Score Index, and Act75 and Act75-0 presented a significant correlation with residual enzyme activity at diagnosis. Markers based on glucocerebrosidase activity have a good correlation with clinical response to ERT. Therefore, it could provide supporting clinical data for dose management in GD1 patients
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