197,572 research outputs found
N. G. Politis. Μελέται, etc., Παροιμίαι · Τόμος Γ.
No full textM. A. N. G. Politis. Μελέται, etc., Παροιμίαι · Τόμος Γ.. In: Revue des Études Grecques, tome 15, fascicule 67,1902. p. 478
Modelamiento de los parámetros ambientales de la distribución de Goya-Malabrigo mediante Maxent
No full textEn este capítulo se explora la aplicación del programa MaxEnt, usando como input los sitios asignados a la entidad arqueológica Goya-Malabrigo, con dos objetivos principales: a) precisar objetivamente los parámetros ambientales asociados a la distribución geográfica (el climatic envelope niche, Post 2013) de esta entidad arqueológica y b) estimar el área mas apta para la distribución de esta entidad en base a dichos parámetros ambientales. Tambien se aborda con el pregrama MaxEnt la distribución de los sitios guaraníes del NEA con el objetivo de compararla con el área apta de ocupación de Goya-Malabrigo.Fil: Politis, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; ArgentinaFil: Domic, Alejandra I.. State University of Pennsylvania; Estados UnidosFil: Bonomo, Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Capriles, José M,. State University of Pennsylvania; Estados Unido
Comentarios sobre el artículo “Más sobre el túmulo de Campana” de G. Politis y M. Bonomo
No full textEl licenciado Luis Abel Orquera actuó como evaluador del artículo de Politis y Bonomo, “Más sobre el Túmulo de Campana”, que se publica en este volumen. A continuación de su revisión hizo referencia a su intervención personal en los hechos del pasado que están siendo discutidos en dicho artículo. Los editores de Relaciones hemos considerado importante publicar ese testimonio como apéndice por considerar que contiene referencias de relevancia para la historia de la arqueología.Sociedad Argentina de Antropologí
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Towards a Theoretical Foundation of the Model-free Bootstrap for Regression and Time Series
No full textThe model-free bootstrap (MFB), first introduced in Politis [2013] followed by the monograph of Politis [2015], and further investigated in a series of papers (cf. Pan and Politis [2016b], Chen and Politis [2019], Das and Politis [2020], etc), is a recent advent in the bootstrap literature. The principle of MFB is to (invertibly) transform the original data to a space of i.i.d. variables, wherein the standard i.i.d. bootstrap is performed for the variables, and then the inverse transform is used to obtain bootstrap samples in the original data space. Because of the wide selection of applicable transforms, the MFB framework can be easily extended for complex data scenarios – such as regression and time series. The term "model-free" relates to the fact that thetransformations are estimated without model assumptions, i.e., nonparametrically.The main purpose of this dissertation is to build a theoretical foundation for the MFB under different setups. Specifically, in Chapter 1, we analyze the MFB under model-free regres- sion setup, and compare it with other methods of interest focusing on conditional coverage of prediction intervals. The concept of pertinent prediction intervals is extended to this setup, and we propose the notion of conjecture testing for predictive inference. In Chapter 2, we establish bootstrap validity of various statistics for a general class of univariate time series under very basic dependence assumptions, using the recently developed m ́approximation technique. In Chapter 3, the MFB algorithm of chapter 2 is further extended to handle multivariate time series, wherein we specifically focus on the generation of prediction regions. We also link the MFB under multivariate context with the well-known copula models. Finally in Chapter 4, we propose a new MFB algorithm for quantile autoregressive processes based on the MFB framework for general Markov process by Pan and Politis [2016b], using an augmented quantile regression estimator
Woodrow Wilson. — L’État. Éléments d’histoire et de pratique politique, trad. franç., (Préface de M. Léon Duguit, professeur à la Faculté de droit de Bordeaux). — Giard et Brière, Paris, 1902
No full textPolitis Nicolas. Woodrow Wilson. — L’État. Éléments d’histoire et de pratique politique, trad. franç., (Préface de M. Léon Duguit, professeur à la Faculté de droit de Bordeaux). — Giard et Brière, Paris, 1902. In: Revue internationale de l'enseignement, tome 51, Janvier-Juin 1906. pp. 474-475
Recent imaging advances in neurology
No full textOver the recent years, the application of neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) has considerably advanced the understanding of complex neurological disorders. PET is a powerful molecular imaging tool, which investigates the distribution and binding of radiochemicals attached to biologically relevant molecules; as such, this technique is able to give information on biochemistry and metabolism of the brain in health and disease. MRI uses high intensity magnetic fields and radiofrequency pulses to provide structural and functional information on tissues and organs in intact or diseased individuals, including the evaluation of white matter integrity, grey matter thickness and brain perfusion. The aim of this article is to review the most recent advances in neuroimaging research in common neurological disorders such as movement disorders, dementia, epilepsy, traumatic brain injury and multiple sclerosis, and to evaluate their contribution in the diagnosis and management of patients
Molecular imaging of levodopa-induced dyskinesias
No full textLevodopa-induced dyskinesias (LIDs) occur in the majority of patients with Parkinson's disease (PD) following years of levodopa treatment. The pathophysiology underlying LIDs in PD is poorly understood, and current treatments generate only minor benefits for the patients. Studies with positron emission tomography (PET) molecular imaging have demonstrated that in advanced PD patients, levodopa administration induces sharp increases in striatal dopamine levels, which correlate with LIDs severity. Fluctuations in striatal dopamine levels could be the result of the attenuated buffering ability in the dopaminergically denervated striatum. Lines of evidence from PET studies indicate that serotonergic terminals could also be responsible for the development of LIDs in PD by aberrantly processing exogenous levodopa and by releasing dopamine in a dysregulated manner from the serotonergic terminals. Additionally, other downstream mechanisms involving glutamatergic, cannabinoid, opioid, cholinergic, adenosinergic, and noradrenergic systems may contribute in the development of LIDs. In this article, we review the findings from preclinical, clinical, and molecular imaging studies, which have contributed to our understanding the pathophysiology of LIDs in PD
Design of experiments (DoE) in pharmaceutical development
No full textAt the beginning of the 20(th) century, Sir Ronald Fisher introduced the concept of applying statistical analysis during the planning stages of research rather than at the end of experimentation. When statistical thinking is applied from the design phase, it enables to build quality into the product, by adopting Deming's profound knowledge approach, comprising system thinking, variation understanding, theory of knowledge and psychology. The pharmaceutical industry was late in adopting these paradigms, compared to other sectors. It heavily focused on blockbuster drugs, while formulation development was mainly performed by One Factor At a Time (OFAT) studies, rather than implementing Quality by Design (QbD) and modern engineering-based manufacturing methodologies. Amongst various mathemarical modeling approaches, Design of Experiments (DoE) is extensively used for the implementation of QbD in both research and industrial settings. In QbD, product and process understanding is the key enabler of assuring quality in the final product. Knowledge is achieved by establishing models correlating the inputs with the outputs of the process. The mathematical relationships of the Critical Process Parameters (CPPs) and Material Attributes (CMAs) with the Critical Quality Attributes (CQAs) define the design space. Consequently, process understanding is well assured and rationally leads to a final product meeting the Quality Target Product Profile (QTPP). This review illustrates the principles of quality theory through the work of major contributors, the evolution of the QbD approach and the statistical toolset for its implementation. As such, DoE is presented in detail since it represents the first choice for rational pharmaceutical development
Ghawr as-Safi Survey and Excavations 2006-2007
No full textKonstantinos D. Politis, Margaret O'Hea, Georgios A. Papaioanno
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