2,465 research outputs found

    A Comparative Study on the Use of Classification Algorithms in Financial Forecasting

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    Financial forecasting is a vital area in computational finance, where several studies have taken place over the years. One way of viewing financial forecasting is as a classification problem, where the goal is to find a model that represents the predictive relationships between predictor attribute values and class attribute values. In this paper we present a comparative study between two bio-inspired classification algorithms, a genetic programming algorithm especially designed for financial forecasting, and an ant colony optimization one, which is designed for classification problems. In addition, we compare the above algorithms with two other state-of-the-art classification algorithms, namely C4.5 and RIPPER. Results show that the ant colony optimization classification algorithm is very successful, significantly outperforming all other algorithms in the given classification problems, which provides insights for improving the design of specific financial forecasting algorithms

    Density and reproductive characteristics of female brown bears in the Cantabrian Mountains, NW Spain

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    Here we present annual nearest-neighbour distances (as a proxy of density) between females with cubs-of-the-year (hereafter FCOY) and reproductive characteristics of brown bears Ursus arctos in the Cantabrian Mountains (NW Spain), from 1989 to 2017. FCOY nearest-neighbour distances and reproduction parameters of 19 focal females followed over several consecutive years (from 2004 to 2017) were obtained from bears inhabiting the western sector of the Cantabrian Mountains, where most of the bear population resides. In contrast, general reproductive characteristics were studied in the whole Cantabrian Mountains (western and eastern sectors together) on a sample of 362 litter sizes and 695 cubs. Mean nearest-neighbour distance between FCOY was 2559 ± 1222 m (range = 1305–4757 m). Mean litter size was significantly larger in the west (1.8 ± 0.2 cubs) than in the east (1.3 ± 0.6 cubs). Mean litter size for the whole of the Cantabrian Mountains was 1.6 ± 0.3 cubs. Litter sizes of one, two and three cubs represented 33.4, 56.1 and 10.5% of observed family groups, respectively. Interannual variations in litter size were not significant for both the western and the eastern areas. Mean cub mortality was 0.2 ± 0.5 cubs and did not vary among years. Cub mortality per litter size was 3.9% for one cub, 69.2% for two cubs and 26.9% for three cubs. Mean reproductive rate of the 19 focal females was 1.5 ± 0.6 cubs (n = 58 litters). Litter size of focal FCOY did not differ from the litter size obtained from systematic observations in the whole Cantabrian Mountains. During this period, cub mortality occurred in 24.1% of the 58 litters. Females usually bred every second year (average litter interval = 2.2 years). The estimated reproductive rate for the bear population was 0.7 young born/year/reproductive adult female

    Research on nonlinear and quantum optics at the photonics and quantum information group of the University of Valladolid

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    We outline the main research lines in Nonlinear and Quantum Optics of the Group of Photonics and Quantum Information at the University of Valladolid. These works focus on Optical Solitons, Quantum Information using Photonic Technologies and the development of new materials for Nonlinar Optics. The investigations on optical solitons cover both temporal solitons in dispersion managed fiber links and nonparaxial spatial solitons as described by the Nonlinear Helmholtz Equation. Within the Quantum Information research lines of the group, the studies address new photonic schemes for quantum computation and the multiplexing of quantum data. The investigations of the group are, to a large extent, based on intensive and parallel computations. Some associated numerical techniques for the development of the activities described are briefly sketched

    Relationship between the dynamics of telomere loss in peripheral blood leukocytes from osteoarthritis patients and mitochondrial DNA haplogroup

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    [Abstract] Objective: To evaluate the evolution of telomere length from peripheral blood leukocytes (PBLs) in subjects from the Osteoarthritis Initiative (OAI) cohort in relation to the incidence of osteoarthritis (OA), and to explore its possible interactive influence with the mitochondrial DNA (mtDNA) haplogroup. Methods: Dynamics of telomere sequence loss were quantified in PBLs from initially healthy individuals (without symptoms or radiological signs), 78 carrying the mtDNA cluster HV, and 47 with cluster JT, from the OAI, during a 72-month follow-up period. The incidence of knee OA during this period (n = 39) was radiographically established when Kellgren-Lawrence (KL) score increased from < 2 at recruitment, to ≥ 2 at the end of 72 months of follow-up. Multivariate analysis using binary logistic regression was performed to assess PBL telomere loss and mtDNA haplogroups as associated risk factors of incidence of knee OA. Results: Carriers of cluster HV showed knee OA incidence twice that of the JT carriers (n = 30 vs 9). The rate of PBL telomere loss was higher in cluster HV carriers and in individuals with incident knee OA. Multivariate analysis showed that the dynamics of PBL telomere shortening can be a consistent risk marker of knee OA incidence. Subjects with nonincident knee OA showed a slower telomere loss than those with incident knee OA; the difference was more significant in carriers of cluster JT than in HV. Conclusion: An increased rate of telomere loss in PBLs may reflect a systemic accelerated senescence phenotype that could be potentiated by the mitochondrial function, increasing the susceptibility of developing knee OA.Instituto de Salud Carlos III; PI17/01987Instituto de Salud Carlos III; PI16/02124Xunta de Galicia; IN607A 2017/1

    Hemolytic activity and siderophore production in different aeromonas species isolated from fish

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    P. 5612-5614The hemolytic activity and siderophore production of several strains of motile aeromonads were determined. The hemolytic activity of Aeromonas caviae and Aeromonas eucrenophila was enhanced after trypsinization of the samples. The enhancement of hemolysis was observed in strains that carried an aerolysin-like gene, detected by a PCR procedure. Siderophore production was demonstrated in all but one strain of Aeromonas jandaei. No apparent relationship was observed between the presence of plasmid DNA and hemolysis or siderophore production.S

    Expansion of CD8+CD57+ T Cells in an Immunocompetent Patient with Acute Toxoplasmosis

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    CD57+ T cells increase in several viral infections like cytomegalovirus, herpesvirus, parvovirus, HIV and hepatitis C virus and are associated with several clinical conditions related to immune dysfunction and ageing. We report for the first time an expansion of CD8+ CD57+ T cells in a young patient with an acute infection with Toxoplasma gondii. Our report supports the concept that CD8+ CD57+ T cells could be important in the control of chronic phase of intracellular microorganisms and that the high numbers of these cells may reflect the continuing survey of the immune system, searching for parasite proliferation in the tissues

    Uso de acidólisis por fosfolipasa A1 inmovilizada para la producción de fosfatidilcolina estructurada con elevado contenido de ácido linoleico conjugado

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    Structured phosphatidylcholine (SPC) was successfully produced via immobilized phospholipase A1 (PLA1) – catalyzed acidolysis of phosphatidylcholine (PC) with conjugated linoleic acid (CLA). The effects of enzyme loading (2, 5, 10, 15 and 20%, with respect to the weight of substrates), temperature (20, 30, 40, 50 and 60 °C) and the molar ratio of substrates (1:2, 1:4, 1:6, 1:8 and 1:10, PC/CLA) were evaluated to maximize the incorporation of CLA into PC. The maximum incorporation of CLA achieved was ca. 90% for 24 h of reaction at 50 °C and 200 rpm, using a 1:4 substrate molar ratio and an enzyme loading of 15%.Fosfatidilcolina estructurada (SPC) fue producida por acidólisis de fosfatidilcolina (PC) y ácido linoleico conjugado (CLA) usando fosfolipasa A1 (PLA1) inmovilizada. Los efectos de carga de enzima (2, 5, 10, 15 y 20%, respecto al peso de los sustratos), temperatura (20, 30, 40, 50 y 60 °C) y la relación molar de sustratos (1:2, 1:4, 1:6, 1:8 y 1:10, PC/CLA) fueron evaluados para alcanzar la más elevada incorporación de CLA en PC. La máxima incorporación de CLA obtenida fue de 90% a 50 °C y 200 rpm, para una relación molar 1:4 con una carga de enzima de 15% después de 24 h

    Cirugía abierta frente a cirugía artroscópica en el tratamiento de la inestabilidad anterior de hombro

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    Se analizan los resultados de una técnica convencional, técnica de Bankart, para el tratamiento de la luxación recidivante anterior de hombro frente a una intervención artroscópica descrita por Rose. Se seleccionan quince pacientes para cada grupo de estudio con un seguimiento postoperatorio medio en torno a los dos años. Los pacientes de cirugía artroscópica se han seleccionado en base a criterios de exclusión preoperatorios e intraoperatorios que requieren la exploración de la estabilidad bajo anestesia y el examen artroscó- pico inicial. En el grupo de cirugía abierta no existe ningún caso de recidiva de la lesión, sólo un paciente no recuperó su nivel de actividad prelesional pero el 73 % de los pacientes presentan restricciones leves de la rotación externa a 90 ° de abducción. En el caso de la cirugía artroscópica un paciente sufrió un nuevo episodio de luxación, dos pacientes no recuperaron su nivel previo de actividad y el 86% presentaban una movilidad completa. Los resultados animan a los autores a continuar desarrollando las técnicas de estabilización artroscópica.We review the results of a conventional technique, Bankart repair, for the treatment of recurrent anterior shoulder instabüity versus an arthroscopic technique developed by Rose. Fifteen patients have been selected for each study group with an average postoperative follow-up around two years. Gandidates for arthroscopic surgery have been selected based on preoperative and intraoperative exclusion criteria. Intraoperative criteria required evaluation of stability under anesthesia and diagnostic arthroscopy. In the open surgery group no redislocations happened. Only one patient did not recover bis previous activity level but 73% had slight restriction to external rotation at 90 ° abduction. In the arthroscopic surgery patients, one of them suffered a redislocation, two cases did not recover their previous activity level but 8 6% kept full shoulder motion. The results encourage the authors to continue the developing trend of arthroscopic stabilization techniques
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