512 research outputs found

    Aplicación de redes neuronales artificiales a la previsión de series temporales no estacionarias o no invertibles

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    En los últimos tiempos se ha comprobado un aumento del interés en la aplicación de las Redes Neuronales Artificiales a la previsión de series temporales, intentando explotar las indudables ventajas de estas herramientas. En este artículo se calculan previsiones de series no estacionarias o no invertibles, que presentan dificultades cuando se intentan pronosticar utilizando la metodología ARIMA de Box-Jenkins. Las ventajas de la aplicación de redes neuronales se aprecian con más claridad, cuando se trata de pronosticar sistemas multivariantes no estacionarios

    Listen Carefully : A Rhetorical Analysis of Speeches Delivered by President George W. Bush

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    The current war in Iraq has been defined as both a war on terror as well as a war to free the people of Iraq. It is a fight against a member of the axis of evil and likewise an attempt to bring democracy to the Middle East. Prior to the start of the war, other countries were warned that they were either with us or against us while American citizens were told that a preemptive strike in Iraq was necessary to stop a country harboring weapons of mass destruction. These phrases were used to both frighten Americans as well as embolden them, to rationalize as well as dignify the cause for war, and as a strategy to define Americans as righteous as well as scare them into protection of their fellow citizens. This thesis will raise questions concerning language and how it produces notions of good and evil as well as how the language used to justify war shapes and molds reality itself. Specifically, this paper will examine four texts. Each is a speech made by President George W. Bush in the months preceding his decision to go to war in Iraq. The initial analysis will be of President George W. Bush’s September 20, 2001 speech in Washington D.C. An examination of Bush\u27s November 10, 2001 speech to the United Nations General Assembly in New York, New York will ensue and will be followed by an interrogation of his 2002 State of the Union Address which was given on January 29, 2002. Finally, Bush\u27s speech to the graduates at West Point Military Academy on June 1, 2002 will be explored. The rhetorical construction of these speeches and how each speech builds on the previous one will be explored. While they were delivered over a period of ten months and appear in different contexts, viewed together, it is obvious that each speech anticipates the next. Ultimately, this paper will demonstrate how the rhetorical maneuvering which is employed in the speeches of George W. Bush is used to both justify the war in Iraq as well as prove that going to war in Iraq was a foregone conclusion by the Bush administration prior to 2001, but which the events of 9/11 only helped to more clearly define

    CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE : IV. LACK OF CLASS DIFFERENTIATION IN THYMIC ANTIGEN-REACTIVE CELLS

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    Thymocytes and marrow cells of unprimed donor mice were mixed in vitro and transplanted into X-irradiated syngeneic mice. 18 hr later, sheep erythrocytes were injected to induce immune responses. Splenic plaque-forming cells (PFC) secreting IgM (direct PFC) or IgG (indirect PFC) hemolytic antibody were enumerated at the time of peak responses. By transplanting graded and limiting numbers of thymocytes with 4 x 107 marrow cells, inocula were found which contained one or a few thymic antigen-reactive cells (ARC) reaching the recipient spleens, interacting with marrow cells, and inducing PFC formation. The frequency values of ARC inferred from direct and indirect plaque assays were very similar, 1 in ∼107 thymocytes. Furthermore, statistical analysis indicated that the formation of direct PFC was not independent of the formation of indirect PFC. This was interpreted to mean that ARC were not specialized themselves and did not determine the molecular class of antibody to be secreted after interaction with marrow cells. Spleens of thymus-marrow grafted mice containing one or two ARC and non-limiting numbers of marrow precursors of PFC (P-PFC), had direct and indirect PFC clustered in several focal areas. Assuming that each focal area represented the progeny of one P-PFC that had interacted with ARC, these results confirmed the statistical evidence for lack of class differentiation in thymic ARC, and also indicated that each ARC or its progeny cells interacted with more than one P-PFC of either class

    CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE : V. CLASS DIFFERENTIATION IN MARROW PRECURSORS OF PLAQUE-FORMING CELLS

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    Marrow cells and thymocytes of unprimed donor mice were mixed in vitro and transplanted into X-irradiated syngeneic hosts. 18 hr later sheep erythrocytes were injected to induce immune responses. Splenic plaque-forming cells (PFC) secreting IgM (direct PFC) or IgG (indirect PFC) hemolytic antibody were enumerated at the time of peak responses. By transplanting graded and limiting numbers of marrow cells with 5 x 107 thymocytes, inocula were found that contained few precursors of PFC (P-PFC) reaching the recipient spleens, interacting with thymocytes, and generating PFC. However, the frequency of responses in relation to the number of grafted marrow cells did not follow Poisson statistics, presumably because the interaction of marrow cells with thymocytes was more complex than a single or a one-to-one cell event. The frequency of direct PFC responses was greater than that of indirect PFC responses in 13 of 15 groups of mice tested. This was interpreted as evidence for the existence of two classes of P-PFC, each of which was restricted to generate either direct or indirect PFC. The precursors of direct PFC were ∼ 15 times more frequent than those of indirect PFC. Since thymic antigen-reactive cells were not differentiated for antibody class, it follows that antigen-sensitive units reactive to sheep erythrocytes owe their class restriction to specialized marrow cells. Specialization of P-PFC may have arisen within marrow cell lines by differentiation, or may have been conferred upon P-PFC by interaction with other cells, including those of the irradiated host

    CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE

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    Investigation into Geomagnetic storms and ionospheric scintillation

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    Understanding how space weather phenomenon affects daily life has been a main focus of space weather studies. In particular, identifying the relationship between solar activities, ionospheric irregularities and consequently ionospheric scintillation has inspired numerous research efforts. Geomagnetic storms fueled by solar activities cause ionospheric irregularities. Ionospheric scintillation occurs when radio signals travel through these irregularities and experience rapid fluctuations in radio signal phase and amplitude. Such fluctuations have great consequences in radio wave based technology such as the Global Position system(GPS) as it causes a loss of lock. Therefore, through the implantation of two GPS Receivers, continuous data was obtained on phase and amplitude of radio signals from the Global Navigation Satellite Systems(GNSS). This data was then thoroughly analyzed to identify scintillation signatures. On January 31st, 2019, scintillation signatures that correlated to a G1 minor geomagnetic storm were observed. In this paper, the method of analysis is adapted from the aforementioned case study to identify past geomagnetic events that possibly correlated with observed scintillation. Through this study, it is hoped that a correlation between geomagnetic storms and ionospheric scintillation in the mid-latitude region will be highlighted

    Usability of the REHOME Solution for the Telerehabilitation in Neurological Diseases: Preliminary Results on Motor and Cognitive Platforms

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    The progressive aging of the population and the consequent growth of individuals with neurological diseases and related chronic disabilities, will lead to a general increase in the costs and resources needed to ensure treatment and care services. In this scenario, telemedicine and e-health solutions, including remote monitoring and rehabilitation, are attracting increasing interest as tools to ensure the sustainability of the healthcare system or, at least, to support the burden for health care facilities. Technological advances in recent decades have fostered the development of dedicated and innovative Information and Communication Technology (ICT) based solutions, with the aim of complementing traditional care and treatment services through telemedicine applications that support new patient and disease management strategies. This is the background for the REHOME project, whose technological solution, presented in this paper, integrates innovative methodologies and devices for remote monitoring and rehabilitation of cognitive, motor, and sleep disorders associated with neurological diseases. One of the primary goals of the project is to meet the needs of patients and clinicians, by ensuring continuity of treatment from healthcare facilities to the patient’s home. To this end, it is important to ensure the usability of the solution by elderly and pathological individuals. Preliminary results of usability and user experience questionnaires on 70 subjects recruited in three experimental trials are presented here
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