4,514 research outputs found

    Algorithm for heart rate extraction in a novel wearable acoustic sensor.

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    Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds - S1 and S2 - that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring

    Measuring home advantage in Spanish Football (1928-2011)

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    Pollard (1986) estableció el procedimiento para analizar la ventaja de jugar en casa, efecto que en términos anglosajones se denomina “home advantage” (HA). La HA ha sido estudiada en multitud de deportes, tanto individuales como de equipo, determinando su existencia y sus posibles causas. Este artículo analiza la HA de la primera división de fútbol español a lo largo de su historia (desde 1928 hasta el 2011). La muestra es de 80 temporadas y 22.015 partidos jugados en las competiciones de liga de máxima categoría española. La HA es de 70,8±0,14 en las máximas categorías del fútbol español en la época en la que el valor de la victoria era de dos puntos (1928-1995) y de 56,7±0,14 cuando se otorgan tres puntos por la victoria (1995-2011Pollard (1986) established the procedure for analyzing the home advantage (HA). The HA has been studied in many different sports, both individual and team sports, determining its existence and its possible causes. This article analyzes the HA of the first division of Spanish football across the history (from 1928 until 2011). The sample is of 80 seasons and 22015 games of the highest level in Spain. The HA (mean±sd) is of 70.8±0.14 in the highest category in Spanish football during the period when a victory was worth two points (1928-1995) and 56.7±0.14 when three points were awarded for a victory (1995-2011

    On high-speed turning of a third-generation gamma titanium aluminide

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    Gamma titanium aluminides are heat-resistant intermetallic alloys predestined to be employed in components suffering from high mechanical stresses and thermal loads. These materials are regarded as difficult to cut, so this makes process adaptation essential in order to obtain high-quality and defect-free surfaces suitable for aerospace and automotive parts. In this paper, an innovative approach for longitudinal external high-speed turning of a third-generation Ti-45Al-8Nb- 0.2C-0.2B gamma titanium aluminide is presented. The experimental campaign has been executed with different process parameters, tool geometries and lubrication conditions. The results are discussed in terms of surface roughness/integrity, chip morphology, cutting forces and tool wear. Experimental evidence showed that, due to the high cutting speed, the high temperatures reached in the shear zone improve chip formation, so a crack-free surface can be obtained. Furthermore, the use of a cryogenic lubrication system has been identified in order to reduce the huge tool wear, which represents the main drawback when machining gamma titanium aluminides under the chosen process condition

    The collisional depolarization of OH(A 2Σ+) and NO(A 2Σ+) with Kr

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    Quantum beat spectroscopy has been used to measure rate coefficients at 300 K for collisional depolarization for NO(A 2Σ+) and OH(A 2Σ+) with krypton. Elastic depolarization rate coefficients have also been determined for OH(A) + Kr, and shown to make a much more significant contribution to the total depolarization rate than for NO(A) + Kr. While the experimental data for NO(A) + Kr are in excellent agreement with single surface quasiclassical trajectory (QCT) calculations carried out on the upper 2A ′ potential energy surface, the equivalent QCT and quantum mechanical calculations cannot account for the experimental results for OH(A) + Kr collisions, particularly at low N. This disagreement is due to the presence of competing electronic quenching at low N, which requires a multi-surface, non-adiabatic treatment. Somewhat improved agreement with experiment is obtained by means of trajectory surface hopping calculations that include non-adiabatic coupling between the ground 1A ′ and excited 2A ′ states of OH(X/A) + Kr, although the theoretical depolarization cross sections still significantly overestimate those obtained experimentally

    Efecto de la edad relativa en el atletismo español

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    La influencia del trimestre de nacimiento sobre el rendimiento de los atletas ha sido ampliamente estudiada, pero siempre en relación a un periodo temporal. La novedad de este trabajo es estudiar el efecto de la edad relativa en relación a los resultados deportivos. Para ello se analizó el efecto de la edad relativa (EER), denominado RAE en inglés, en los atletas españoles (3.313) que han conseguido las mejores marcas de todos los tiempos atletas desde 1940 hasta la actualidad. Se ha identificado la fecha de nacimiento de los atletas y se ha extraído el mes y el trimestre de nacimiento. La prueba de Chi-cuadrado (χ2) se ha utilizado para elaborar los resultados, que muestran que este efecto es consistente tanto en el atletismo masculino como en el femenino. En el atletismo masculino existe en todas las categorías de edad, mientras que en el atletismo femenino el efecto es mucho más débil, apareciendo sólo en la categoría absoluta y en la juvenil. En cuanto a los sectores de competición los resultados no muestran un patrón de comportamiento claro

    Identification and validation of oncologic miRNA biomarkers for Luminal A-like breast cancer

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    Introduction: Breast cancer is a common disease with distinct tumor subtypes phenotypically characterized by ER and HER2/neu receptor status. MiRNAs play regulatory roles in tumor initiation and progression, and altered miRNA expression has been demonstrated in a variety of cancer states presenting the potential for exploitation as cancer biomarkers. Blood provides an excellent medium for biomarker discovery. This study investigated systemic miRNAs differentially expressed in Luminal A-like (ER+PR+HER2/neu-) breast cancer and their effectiveness as oncologic biomarkers in the clinical setting. Methods: Blood samples were prospectively collected from patients with Luminal A-like breast cancer (n=54) and controls (n=56). RNA was extracted, reverse transcribed and subjected to microarray analysis (n=10 Luminal A-like; n=10 Control). Differentially expressed miRNAs were identified by artificial neural network (ANN) data-mining algorithms. Expression of specific miRNAs was validated by RQ-PCR (n=44 Luminal A; n=46 Control) and potential relationships between circulating miRNA levels and clinicopathological features of breast cancer were investigated. Results: Microarray analysis identified 76 differentially expressed miRNAs. ANN revealed 10 miRNAs for further analysis ( miR-19b, miR-29a, miR-93, miR-181a, miR-182, miR-223, miR-301a, miR-423-5p, miR-486-5 and miR-652 ). The biomarker potential of 4 miRNAs ( miR-29a, miR-181a , miR-223 and miR-652 ) was confirmed by RQ-PCR, with significantly reduced expression in blood of women with Luminal A-like breast tumors compared to healthy controls (p=0.001, 0.004, 0.009 and 0.004 respectively). Binary logistic regression confirmed that combination of 3 of these miRNAs ( miR-29a, miR-181a and miR-652 ) could reliably differentiate between cancers and controls with an AUC of 0.80. Conclusion: This study provides insight into the underlying molecular portrait of Luminal A-like breast cancer subtype. From an initial 76 miRNAs, 4 were validated with altered expression in the blood of women with Luminal A-like breast cancer. The expression profiles of these 3 miRNAs, in combination with mammography, has potential to facilitate accurate subtype- specific breast tumor detection

    Observation of Dirac plasmons in a topological insulator

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    Plasmons are the quantized collective oscillations of electrons in metals and doped semiconductors. The plasmons of ordinary, massive electrons are since a long time basic ingredients of research in plasmonics and in optical metamaterials. Plasmons of massless Dirac electrons were instead recently observed in a purely two-dimensional electron system (2DEG)like graphene, and their properties are promising for new tunable plasmonic metamaterials in the terahertz and the mid-infrared frequency range. Dirac quasi-particles are known to exist also in the two-dimensional electron gas which forms at the surface of topological insulators due to a strong spin-orbit interaction. Therefore,one may look for their collective excitations by using infrared spectroscopy. Here we first report evidence of plasmonic excitations in a topological insulator (Bi2Se3), that was engineered in thin micro-ribbon arrays of different width W and period 2W to select suitable values of the plasmon wavevector k. Their lineshape was found to be extremely robust vs. temperature between 6 and 300 K, as one may expect for the excitations of topological carriers. Moreover, by changing W and measuring in the terahertz range the plasmonic frequency vP vs. k we could show, without using any fitting parameter, that the dispersion curve is in quantitative agreement with that predicted for Dirac plasmons.Comment: 11 pages, 3 figures, published in Nature Nanotechnology (2013

    Discovering the constrained NMSSM with tau leptons at the LHC

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    The constrained Next-to-Minimal Supersymmetric Standard Model (cNMSSM) with mSugra-like boundary conditions at the GUT scale implies a singlino-like LSP with a mass just a few GeV below a stau NLSP. Hence, most of the squark/gluino decay cascades contain two tau leptons. The gluino mass >~ 1.2 TeV is somewhat larger than the squark masses of >~ 1 TeV. We simulate signal and background events for such a scenario at the LHC, and propose cuts on the transverse momenta of two jets, the missing transverse energy and the transverse momentum of a hadronically decaying tau lepton. This dedicated analysis allows to improve on the results of generic supersymmetry searches for a large part of the parameter space of the cNMSSM. The distribution of the effective mass and the signal rate provide sensitivity to distinguish the cNMSSM from the constrained Minimal Supersymmetric Standard Model in the stau-coannihilation region.Comment: 18 pages, 3 Figure
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