464 research outputs found

    Ética e Investigación Científica en la Sociedad Globalizada

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    http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0370-41062009000400001&nrm=is

    The logistic map and the birth of period-3 cycle

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    The goal of this paper is to present a proof that for the logistic map the period-3 begins at . The third-iterate map is the key for understanding the birth of the period-3 cycle. Any point in a period-3 cycle repeats every three iterates by definition. Such points satisfy the condition ,and they are therefore fixed points of the third-iterate map. This fact and the so called tangent bifurcation for the logistic map, as well as the fixed points definition, are used for finding the value. The algebraic treatment utilizes some properties of symmetric polynomials in three variables. For the purposes of this paper, the bifurcation diagram for the logistic map is also presented, as well as a program in Mathematica for its construction

    Product complexity assessment for a Proactive-DFA implementation (Simplicity + Simplicity = Complexity)

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    This thesis presents product complexity as a criterion for the optimisation of product design in the light of an Assembly-Oriented Design and Design for Assembly implementation. It takes a holistic approach to the evaluation of the product architecture by presenting a set of indicators that help examine the product structure at two different levels: Assembly and Component complexity. Assembly complexity assessment is further sub-divided into Structural and Sequence complexity. The latter is a well-known and thoroughly studied area in assembly sequence evaluation, whereas the former gives a novel and original approach to drawing attention to those areas in the product configuration that will consume more resources (i.e. time and tooling required). Component complexity, on the other hand, is sub-divided into manufacturing and process handling/manipulation complexity. The first area has been addressed by the manufacturing analysis section of most Design for Assembly and Manufacturing methodologies, but it has been traditionally addressed as a manual and chart-based evaluation. This is a rigid approach that leaves little room for expansion and has no connection with the product structure. The metrics presented in this work embody a new approach that takes into account the component-to-component interactions and allows the analysis of component shape by extracting its geometry characteristics and comparing them with particular traits of the manufacturing processes available to the designer. Additionally, the metrics presented in this work can be used to make an assessment of the product complexity at a particular point (static complexity) in the development cycle. They can also be registered over a period of time to provide an estimate of the possible consequences of the decisions made during a part of the development cycle (dynamic complexity). By using the methods developed, designers could reduce production costs and increase the reliability of their products.Ph

    Moving magnetic features around a pore

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    A. J. Kaithakkal et. al.©2017 The American Astronomical Society. All rights reserved.Spectropolarimetric observations from Sunrise/IMaX, obtained in 2013 June, are used for a statistical analysis to determine the physical properties of moving magnetic features (MMFs) observed near a pore. MMFs of the same and opposite polarity, with respect to the pore, are found to stream from its border at an average speed of 1.3 km s−1 and 1.2 km s−1, respectively, with mainly same-polarity MMFs found further away from the pore. MMFs of both polarities are found to harbor rather weak, inclined magnetic fields. Opposite-polarity MMFs are blueshifted, whereas same-polarity MMFs do not show any preference for up- or downflows. Most of the MMFs are found to be of sub-arcsecond size and carry a mean flux of ~1.2 × 1017 Mx.The German contribution to Sunrise and its reflight was funded by the Max Planck Foundation, the Strategic Innovations Fund of the President of the Max Planck Society (MPG), DLR, and private donations by supporting members of the Max Planck Society, which is gratefully acknowledged. The Spanish contribution was funded by the Ministerio de Economía y Competitividad under Projects ESP2013-47349-C6 and ESP2014-56169-C6, partially using European FEDER funds. The HAO contribution was partly funded through NASA grant number NNX13AE95G. This work was partly supported by the BK21 plus program through the National Research Foundation (NRF) funded by the Ministry of Education of Korea.Peer reviewe

    The history of a quiet-Sun magnetic element revealed by IMaX/SUNRISE

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    Isolated flux tubes are considered to be fundamental magnetic building blocks of the solar photosphere. Their formation is usually attributed to the concentration of magnetic field to kG strengths by the convective collapse mechanism. However, the small size of the magnetic elements in quiet-Sun areas has prevented this scenario from being studied in fully resolved structures. Here we report on the formation and subsequent evolution of one such photospheric magnetic flux tube, observed in the quiet Sun with unprecedented spatial resolution (0\farcs 15 - 0\farcs 18) and high temporal cadence (33 s). The observations were acquired by the Imaging Magnetograph Experiment (IMaX) aboard the \textsc{Sunrise} balloon-borne solar observatory. The equipartition field strength magnetic element is the result of the merging of several same polarity magnetic flux patches, including a footpoint of a previously emerged loop. The magnetic structure is then further intensified to kG field strengths by convective collapse. The fine structure found within the flux concentration reveals that the scenario is more complex than can be described by a thin flux tube model with bright points and downflow plumes being established near the edges of the kG magnetic feature. We also observe a daisy-like alignment of surrounding granules and a long-lived inflow towards the magnetic feature. After a subsequent weakening process, the field is again intensified to kG strengths. The area of the magnetic feature is seen to change in anti-phase with the field strength, while the brightness of the bright points and the speed of the downflows varies in phase. We also find a relation between the brightness of the bright point and the presence of upflows within it.Comment: 13 pages. Accepted in ApJ. Animation 1 can be viewed and downloaded from: http://spg.iaa.es/downloads.as

    Arteriolopatía calcificante urémica, reporte de un caso tratado con tiosulfato de sodio

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    We describe a case of calcific uremic arteriolopathyinitially associated with skin lesions within the context of a patient with chronic kidney disease on automated peritoneal dialysis therapy. Among the most relevant findings, the patient hadhyperphosphatemia, normocalcemia and severe hyperparathyroidism without nodular hyperplasia. Clinical improvement with multimodal management of enhancement in dialysis therapy and intravenous sodium thiosulfate is highlighted. Calciphylaxis is a disorder that has a high morbidity and mortality, secondary to sepsis. It occurs more frequently in patients with chronic renal failure who are on hemodialysis. It is characterized by systemic medial calcification of the arterioles, triggering ischemia and subcutaneous necrosis of skin and soft tissues. Histopathological evaluation helps to confirm the diagnosis.Describimos un caso de arteriolopatía calcificante urémica asociada,  inicialmente, a lesiones cutáneas,en unpaciente con insuficiencia renal crónica, en terapia de diálisis peritoneal automatizada, como hallazgos másrelevantes presentaba hiperfosfatemia, normocalcemia e hiperparatiroidismo severo sin hiperplasia nodular.Se destaca la mejoría clínica con manejo multimodal de intensificación en la terapia dialítica y tiosulfato desodio intravenoso.La calcifilaxis es un trastorno que debuta con alta morbilidad ymortalidad, secundaria a sepsis, ocurre con mayor frecuencia en pacientes con insuficiencia renal crónica que se encuentran en hemodiálisis. Se caracteriza por calcificación sistémica en la media de las arteriolas, desencadenándose isquemia y necrosis subcutánea de piel y tejidos blandos. La evaluación histopatológica ayuda a confirmar el diagnóstico

    The second flight of the Sunrise Balloon-borne Solar Observatory: overview of instrument updates, the flight, the data, and first results

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    S. K. Solanki et. al.©2017 The American Astronomical Society. All rights reserved.The Sunrise balloon-borne solar observatory, consisting of a 1 m aperture telescope that provides a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in 2013 June. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg ii k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000 Å after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR 11768 observed relatively close to disk center is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500 G, and while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.The German contribution to Sunrise and its reflight was funded by the Max Planck Foundation, the Strategic Innovations Fund of the President of the Max Planck Society (MPG), DLR, and private donations by supporting members of the Max Planck Society, which is gratefully acknowledged. The Spanish contribution was funded by the Ministerio de Economía y Competitividad under Projects ESP2013-47349-C6 and ESP2014-56169-C6, partially using European FEDER funds. The National Center for Atmospheric Research is sponsored by the National Science Foundation. The HAO contribution was partly funded through NASA grant number NNX13AE95G. This work was partly supported by the BK21 plus program through the National Research Foundation (NRF) funded by the Ministry of Education of Korea. L.G. acknowledges research funding from the State of Lower Saxony, Germany. SDO is a mission of NASA's Living With a Star (LWS) program. The SDO/HMI data were provided by the Joint Science Operation Center (JSOC). The National Solar Observatory (NSO) is operated by the Association of Universities for Research in Astronomy (AURA) Inc. under a cooperative agreement with the National Science Foundation.Peer reviewe

    Mean Platelet Volume in Neonatal Sepsis: Meta-Analysis of Observational Studies

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    "first_pagesettingsOrder Article Reprints Open AccessSystematic Review Mean Platelet Volume in Neonatal Sepsis: Meta-Analysis of Observational Studies by Carlos J. Toro-Huamanchumo 1ORCID,Cielo Cabanillas-Ramirez 2,3ORCID,Carlos Quispe-Vicuña 3,4ORCID,Jose A. Caballero-Alvarado 5ORCID,Darwin A. León-Figueroa 3,6ORCID,Nicolás Cruces-Tirado 7 andJoshuan J. Barboza 3,8,*ORCID 1 Escuela de Medicina, Universidad Cesar Vallejo, Trujillo 13007, Peru 2 Escuela de Medicina, Universidad Peruana de Ciencias Aplicadas, Lima 15023, Peru 3 Unidad de Revisiones Sistemáticas y Meta-Análisis, Tau-Relaped Group, Trujillo 13007, Peru 4 Sociedad Científica San Fernando, Universidad Nacional Mayor de San Marcos, Lima 15081, Peru 5 Facultad de Medicina, Universidad Privada Antenor Orrego, Trujillo 13007, Peru 6 Facultad de Medicina Humana, Universidad de San Martín de Porres, Chiclayo 14000, Peru 7 Facultad de Ciencias de la Salud, Universidad Señor de Sipán, Chiclayo 14006, Peru 8 Vicerrectorado de Investigación, Universidad Norbert Wiener, Lima 15046, Peru * Author to whom correspondence should be addressed. Children 2022, 9(12), 1821; https://doi.org/10.3390/children9121821 Received: 5 October 2022 / Revised: 21 November 2022 / Accepted: 22 November 2022 / Published: 25 November 2022 (This article belongs to the Section Pediatric Infectious Diseases) Download Browse Figures Review Reports Versions Notes Abstract Introduction: Early onset neonatal sepsis (EONS), particularly in preterm sepsis, is a potentially fatal issue. Evaluation of mean platelet volume (MPV) as an EONS predictor was the goal. Methods: Four databases were used to conduct a systematic evaluation of cohort and case–control studies. Up till the end of October 2022, 137 articles were found utilizing the search method. Following the review, 12 studies were included. Leukocytes, MPV, platelets, gender, birth weight, gestational age, mortality, and C-reactive protein (CRP) were all taken into account while analyzing the prediction of EONS. Inverse-variance methodology and the random-effects model were used. Using GRADE, the evidence’s quality was evaluated. Results: Neonatal patients with sepsis had significantly higher MPV levels than do neonates without sepsis (MD 1.26; 95% CI 0.89–1.63; p < 0.001). An increased MPV during the first 24 h postpartum was associated with high CRP values and high risk of neonatal mortality. In the investigations, the MPV cutoff for sepsis patients was 9.95 (SD 0.843). Overall certainty of the evidence was very low. Conclusions: The increased MPV during the first 24 h postpartum may be predictive of EONS and mortality. Future studies are warranted.

    "Eficacia de los programas de tratamiento para ciberadicción en niños y adolescentes: revisión sistemática y meta-análisis "

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    "El objetivo de este estudio fue evaluar la eficacia de los programas de tratamiento para la ciberadicción en niños y adolescentes. Material y Métodos: Se realizó la búsqueda en cinco bases de datos. Se seleccionaron ensayos controlados aleatorizados (ECA) o estudios de cohorte que evaluaron la eficacia de programas de tratamiento para la ciberadicción en niños y adolescentes. El desenlace primario fue la disminución de las horas en uso del internet. Para el meta-análisis, se utilizó el modelo de efectos aleatorios con método de varianza inversa. Resultados: Se identificaron siete artículos que fueron incluidos en la revisión sistemática (3 Ensayos controlados aleatorizados y 4 cohortes retrospectivas), con un total de 2396 participantes. La edad media fue de 14 años (SD 1.96). La duración del tratamiento entre todos los estudios publicados varió entre 4 días hasta los 3 meses. Se encontró que los tratamientos para la ciberadicción reducen las horas de conexión a internet en 1.18 horas por semana, comparado con cualquier tratamiento de control (MD 1.18; 95%CI -2.1825 a -0.1754; p= 0.02). Conclusiones: Los tratamientos para la ciberadicción, independientemente del tipo de intervención reducen las horas de conexión a internet
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