4,543 research outputs found
Estimation and forecasting in SUINAR(1) model
This work considers a generalization of the INAR(1) model to the panel data first order Seemingly Unrelated INteger AutoRegressive Poisson model, SUINAR(1). It presents Bayesian and classical methodologies to estimate the parameters of Poisson SUINAR(1) model and to forecast future observations of the process. In particular, prediction intervals for forecasts - classical approach - and HPD prediction intervals - Bayesian approach - are derived. A simulation study is provided to give additional insight into the finite sample behaviour of the parameter estimates and forecasts
Replicated INAR(1) processes
Replicated time series are a particular type of repeated measures, which consist of time-sequences of measurements taken from several subjects (experimental units). We consider independent replications of count time series that are modelled by first-order integer-valued autoregressive processes, INAR(1). In this work, we propose several estimation methods using the classical and the Bayesian approaches and both in time and frequency domains. Furthermore, we study the asymptotic properties of the estimators. The methods are illustrated and their performance is compared in a simulation study. Finally, the methods are applied to a set of observations concerning sunspot data.PRODEP II
Forecasting in INAR(1) model
In this work we consider the problem of forecasting integer-valued time series, modelled by the INAR(1) process introduced by McKenzie (1985) and Al-Osh and Alzaid (1987). The theoretical properties and practical applications of INAR and related processes have been discussed extensively in the literature but there is still some discussion on the problem of producing coherent, i.e. integer-valued, predictions. Here Bayesian methodology is used to obtain point predictions as well as confidence intervals for future values of the process. The predictions thus obtained are compared with their classic counterparts. The proposed approaches are illustrated with a simulation study and a real example
Anisotropy and nonlinearity in superlattices
This paper uses analytical expressions for the nonlinear optical absorption of superlattices by treating them as anisotropic media. The controllable system shows that the nonlinearities increase with anisotropy suggesting that strongly anisotropic materials such as those used for solar cells may also be useful for nonlinear optical applications
Hodgkin's Disease in HIV Patients: Two Clinical Case Reports
Os autores apresentam dois casos de febre prolongada em doente com infecção VIH. O seu estudo conduziu ao diagnóstico de Doença de Hodgkin
A VULNERABILIDADE: SUAS (RE)CONFIGURAÇÕES, PARADOXOS E CONTORNOS NA EXPERIÊNCIA LATINO- AMERICANA
The present text uses Lautier106's work as a term, in order to articulate it with contemporary social theories, considering that in the last two decades Latin America would experience a tension between two discourses, worldviews and ways of making society. : on the one hand a rational discourse driven by longings. On the other hand, speeches that speak of what is required, in which the most used words are: law and citizenship.O presente texto utiliza como termo, para a articulação com as vertentes das teori- as sociais contemporâneas, o trabalho de Lautier106, ao ponderar que a América Latina viveria nas últimas duas décadas uma tensão entre dois discursos, visões de mundo e formas de fazer sociedade: por um lado um discurso racional e impulsionado por ansei- os. Por outro lado, discursos que falam daquilo que se exige, em que as palavras mais utilizadas são: direito e cidadania
The use of histological analysis for the detection of somatic embryos in sugarcane
The aim of this study was to establish an in vitro system for the induction, maturation and regeneration of somatic embryo in sugarcane from buds of cultivar RB 867515. Embryogenic calluses were obtained on semi-solid MS medium supplemented with 4.42 mg L-1 2,4-D. After four weeks of culture of explants on the callus induction medium, globular structures were obtained. At the end of 20 days in maturation medium, somatic embryos were observed. Histological analysis showed somatic embryos with caulinarand root apex, protodermal tissue, and the vascular system, which apparently has no connection with the vascular tissue explant that gave rise to it confirming the presence of the somatic embryo. The embryos were transferred to regeneration medium containing 1 mg L-1 GA3 and BAP, and after 1 to 2 weeks of culture, green points were observed, indicating the beginning of the formation of shoots. Key words: Saccharum spp, bud culture, 2.4-D, morphogenetic pathway, embryogenesis, plant regeneration
ANÁLISE DO CRIME DE PORTE DE DROGAS PARA CONSUMO PRÓPRIO E DE SUA POSSÍVEL DESCRIMINALIZAÇÃO
The theme of this article is the analysis of drug possession crime and its possible decriminalization. The following problem was investigated: Having as premise the conjuncture of legal and social perspectives, is it possible to decriminalize the drugs possession conduct for own use in the current brazilian scenario? The following hypothesis was considered: It is believed in the possibility of decriminalization of drugs possession conduct for own consumption in the current brazilian scenario. The general objective is to analyze the possibility of decriminalization of drugs possession conduct for own use. The specific objectives are: to study the historical construction of drug use regulation in national legislation; evaluate the typification of drug possession conduct for own consumption, especially regarding sanctioned conduct and comminuted penalties; examine the possible decriminalization of the conduct in study. This work discusses the possibility of decriminalization of drugs possession conduct for own use that has intensified in recent years. The issue is in analysis in various social, academic and legal circles and requires attention at a time when there is a transition and confrontation of thoughts. This is a theoretical qualitative research lasting six months.O tema deste artigo é análise do crime de porte de drogas para consumo próprio e de sua possível descriminalização. Investigou-se o seguinte problema: Tendo como premissa a conjuntura de perspectivas jurídicas e sociais, é possível a descriminalização da conduta de porte de drogas para consumo próprio no atual cenário brasileiro? Cogitou-se a seguinte hipótese: Acredita-se na possibilidade da descriminalização da conduta de porte de drogas para consumo próprio no atual cenário brasileiro. O objetivo geral é analisar a possibilidade de descriminalização da conduta de posse de drogas para consumo próprio. Os objetivos específicos são: estudar a construção histórica da regulamentação do uso de drogas na legislação nacional; avaliar a tipificação da conduta de porte de drogas para consumo próprio, especialmente no que concerne as condutas sancionadas e penas cominadas; examinar a possível descriminalização da conduta em estudo. Neste trabalho debate-se a possibilidade de descriminalização da conduta de porte de drogas para consumo próprio ter intensificado nos últimos anos. A questão encontra-se em análise nos mais diversos meios sociais, acadêmicos e jurídicos e requer atenção em um momento em que se verifica uma transição e confronto de pensamentos. Trata-se de uma pesquisa qualitativa teórica com duração de seis meses
Active Electric Imaging: Body-Object Interplay and Object's “Electric Texture”
This article deals with the role of fish's body and object's geometry on determining the image spatial shape in pulse Gymnotiforms. This problem was explored by measuring local electric fields along a line on the skin in the presence and absence of objects. We depicted object's electric images at different regions of the electrosensory mosaic, paying particular attention to the perioral region where a fovea has been described. When sensory surface curvature increases relative to the object's curvature, the image details depending on object's shape are blurred and finally disappear. The remaining effect of the object on the stimulus profile depends on the strength of its global polarization. This depends on the length of the object's axis aligned with the field, in turn depending on fish body geometry. Thus, fish's body and self-generated electric field geometries are embodied in this “global effect” of the object. The presence of edges or local changes in impedance at the nearest surface of closely located objects adds peaks to the image profiles (“local effect” or “object's electric texture”). It is concluded that two cues for object recognition may be used by active electroreceptive animals: global effects (informing on object's dimension along the field lines, conductance, and position) and local effects (informing on object's surface). Since the field has fish's centered coordinates, and electrosensory fovea is used for exploration of surfaces, fish fine movements are essential to perform electric perception. We conclude that fish may explore adjacent objects combining active movements and electrogenesis to represent them using electrosensory information
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