The effect of the linear term on the wavelet estimator of primordial non-Gaussianity

In this work we present constraints on different shapes of primordial non-Gaussianity using the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year data and the spherical Mexican hat wavelet fnl estimator including the linear term correction. In particular we focus on the local, equilateral and orthogonal shapes. We first analyse the main statistical properties of the wavelet estimator and show the conditions to reach optimality. We include the linear term correction in our estimators and compare the estimates with the values already published using only the cubic term. The estimators are tested with realistic WMAP simulations with anisotropic noise and the WMAP KQ75 sky cut. The inclusion of the linear term correction shows a negligible improvement (< 1 per cent) in the error-bar for any of the shapes considered. The results of this analysis show that, in the particular case of the wavelet estimator, the optimality for WMAP anisotropy levels is basically achieved with the mean subtraction and in practical terms there is no need of including a linear term once the mean has been subtracted. Our best estimates are now: local fnl = 39.0 +/ 21.4, equilateral fnl = -62.8 +/- 154.0 and orthogonal fnl = -159.8 +/- 115.1 (all cases 68 per cent CL). We have also computed the expected linear term correction for simulated Planck maps with anisotropic noise at 143 GHz following the Planck Sky Model and including a mask. The improvement achieved in this case for the local fnl error-bar is also negligible (0.4 per cent).Comment: 8 pages, 5 figures, 4 tables. Minor revision, one figure added, accepted for publication in MNRA

The halloween effect in european equity mutual funds

Bouman and Jacobsen (2002) documented the existence of a calendar anomaly in stock market returns, which they call the Halloween effect, based on the fact that the returns during the months of May to October tend to be lower than returns during the months of November to April. Following closely the methodology used by Bouman and Jacobsen (2002), we investigate the presence of the Halloween effect in the European Equity Mutual Funds from 1997 to 2013. We conclude that: i) the Halloween Effect is statistically and economically significant; ii) this effect has disappeared after the Bouman and Jacobsen publication; iii) this anomaly might be due to the negative average returns during the months of May to October, rather than a higher performance during the period from November to April; and iv) an investment strategy based on this anomaly clearly beats the classical buy and hold strategy

AVALIAÇÃO DE MÉTODOS DE ESTIMAÇÃO DE ALTURA E DE ESTRATIFICAÇÃO VERTICAL EM UMA FLORESTA ESTACIONAL SEMIDECIDUAL

CURTO, Rafaella De Angeli. Avaliação de métodos de estimação de altura e de estratificação vertical em uma Floresta Estacional Semidecidual. 2011. Dissertação (Mestrado em Ciências Florestais) - Universidade Federal do Espírito Santo, Alegre-ES. Orientador: Prof. Dr. Gilson Fernandes da Silva. Coorientador: Prof. Dr. José Eduardo Macedo Pezzopane. Este estudo teve como objetivo avaliar métodos de estimação de altura total de árvores e métodos de estratificação vertical em uma floresta nativa. O presente estudo foi realizado em um fragmento de 52 ha de Floresta Estacional Semidecidual, conhecido como Floresta do Rosal, localizado no município de GuaçuíES. Para tanto, empregou-se o método de amostragem de área fixa, 2sendo distribuído um total de 16 parcelas de 600 m de forma sistemática no campo, totalizando uma área amostrada de 0,96 ha. Foi realizada uma análise descritiva dos dados de altura total de árvores e para avaliar a precisão na obtenção dessa variável foram propostos cinco métodos de estimação: Hipsômetro Vertex; Clinômetro digital; estimação com auxílio de uma régua de 15 metros; e estimações visuais com e sem treinamento; em três classes de altura: Classe 1 (15,00-17,99 m); Classe 2 (18,00-20,99 m) e; Classe 3 (>21,00 m), totalizando 15 tratamentos. Para comparar os tratamentos, foram mensurados 211 indivíduos, 124 em terreno plano e 87 em terreno inclinado, sendo a altura total desses, obtida por meio de escalada. Os dados de altura total foram comparados pelo teste t, a 5% de probabilidade, sendo realizadas também análises gráficas de resíduos e estatísticas complementares. Foram avaliados também a velocidade de execução dos métodos, além dos fatores:número de operadores, custo, robustez, facilidade de observação e compacidade. Para a avaliação da estratificação vertical, foram utilizados quatro diferentes métodos, sendo eles: Método 1 - Souza (1990); Método 2 - Souza et al. (2003); Método 3 - IUFRO; e Método 4 - Calegário et al. (1994). Além disso, foram avaliadas a composição florística, diversidade, estrutura horizontal e diamétrica da floresta em estudo. Com relação aos métodos de estimação de altura, o método de estimativa sem treinamento apresentou o pior desempenho quanto à precisão, para as duas condições de terreno avaliadas e o melhor desempenho foi para a estimativa com treinamento, sendo que a declividade afetou a estimativa da altura. Houve tendência em subestimar a altura com o aumento das classes, já o método de estimativa sem treinamento subestimou em todas as classes. Houve diferença quanto ao tempo médio para a estimação da altura entre os métodos e quanto ao efeito da classe, ressalvando algumas exceções. Foram amostrados 1596 indivíduos com DAP maior ou igual a 5 cm, totalizando 246 espécies. As famílias mais representativas em número de espécies foram: Fabaceae, Lauraceae, Myrtaceae e Rubiaceae. O índice de diversidade de Shannon-Weaver (H encontrado na amostragem alcança um valor expressivo. As espécies mais importantes da comunidade, tomando-se como base o IVI%, são: Mabea fistulifera, Siparuna guianensis, Pseudopiptadenia contorta, Apuleia leiocarpa e Myrcia fallax. A estrutura diamétrica do fragmento florestal estudado apresenta ertido, comum às florestas inequiâneas. Dentre os métodos de estratificação vertical, o método 1 não permitiu análise detalhada sobre o comportamento das espécies no estrato II, por apresentar tendências fortes em concentrar um maior número de indivíduos no referido estrato, já o método 2, permitiu um maior detalhamento dos estratos. O método 3, minimizou o problema encontrado no método 1, porém a mudança da altura dominante da amostragem pode mudar toda a discussão, demosntrando fragilidade no método. O método 4 não trouxe bons resultados para a estratificação da floresta em estudo, pois dividiu a floresta em apenas dois estratos de altura. Palavras-chave: floresta estacional semidecidual, estimação de altura, estratificação vertical

Wilkinson Microwave Anisotropy Probe 7-yr constraints on fNL with a fast wavelet estimator

A new method to constrain the local non-linear coupling parameter fNL based on a fast wavelet decomposition is presented. Using a multiresolution wavelet adapted to the HEALPix pixelization, we have developed a method that is 10^2 times faster than previous estimators based on isotropic wavelets and 10^3 faster than the KSW bispectrum estimator, at the resolution of the Wilkinson Microwave Anisotropy Probe (WMAP) data. The method has been applied to the WMAP 7-yr V+W combined map, imposing constraints on fNL of -69 < fNL < 65 at the 95 per cent CL. This result has been obtained after correcting for the contribution of the residual point sources which has been estimated to be fNL = 7 +/- 6. In addition, a Gaussianity analysis of the data has been carried out using the third order moments of the wavelet coefficients, finding consistency with Gaussianity. Although the constrainsts imposed on fNL are less stringent than those found with optimal estimators, we believe that a very fast method, as the one proposed in this work, can be very useful, especially bearing in mind the large amount of data that will be provided by future experiments, such as the Planck satellite. Moreover, the localisation of wavelets allows one to carry out analyses on different regions of the sky. As an application, we have separately analysed the two hemispheres defined by the dipolar modulation proposed by Hoftuft et al. (2009). We do not find any significant asymmetry regarding the estimated value of fNL in those hemispheres.Comment: 8 pages, 5 figures. Submitted and Accepted for publication in MNRA

Crescimento em diâmetro de Araucaria angustifolia em plantio não manejado.

Resumo

Making materials for packaging circularity

Circular packaging materials are becoming increasingly relevant to ensure sustainable and environmentally friendly solutions for citizens and future generations. This work aims to present a glimpse of the current state of research by analysing fifty relevant case studies of packaging materials on the market or under development (for food, disposables, cosmetics, luxury, electronics, healthcare, etc.). The conducted analysis and clustering activity pointed out prominent development trends for incoming years. The study is supported by three multidisciplinary laboratory experiences of the Making Materials1 research team of Politecnico di Milano, in which end-of-life packaging can be considered no longer a waste to dispose of but a new resource for subsequent production. The collaboration between all the stakeholders in the process is crucial to make this closed cycle work and be efficient

A Frequency Comb calibrated Solar Atlas

The solar spectrum is a primary reference for the study of physical processes in stars and their variation during activity cycles. In Nov 2010 an experiment with a prototype of a Laser Frequency Comb (LFC) calibration system was performed with the HARPS spectrograph of the 3.6m ESO telescope at La Silla during which high signal-to-noise spectra of the Moon were obtained. We exploit those Echelle spectra to study the optical integrated solar spectrum . The DAOSPEC program is used to measure solar line positions through gaussian fitting in an automatic way. We first apply the LFC solar spectrum to characterize the CCDs of the HARPS spectrograph. The comparison of the LFC and Th-Ar calibrated spectra reveals S-type distortions on each order along the whole spectral range with an amplitude of +/-40 m/s. This confirms the pattern found by Wilken et al. (2010) on a single order and extends the detection of the distortions to the whole analyzed region revealing that the precise shape varies with wavelength. A new data reduction is implemented to deal with CCD pixel inequalities to obtain a wavelength corrected solar spectrum. By using this spectrum we provide a new LFC calibrated solar atlas with 400 line positions in the range of 476-530, and 175 lines in the 534-585 nm range. The new LFC atlas improves the accuracy of individual lines by a significant factor reaching a mean value of about 10 m/s. The LFC--based solar line wavelengths are essentially free of major instrumental effects and provide a reference for absolute solar line positions. We suggest that future LFC observations could be used to trace small radial velocity changes of the whole solar photospheric spectrum in connection with the solar cycle and for direct comparison with the predicted line positions of 3D radiative hydrodynamical models of the solar photosphere.Comment: Accept on the 15th of October 2013. 9 pages, 10 figures. ON-lINE data A&A 201

Improved constraints on primordial non-Gaussianity for the Wilkinson Microwave Anisotropy Probe 5-yr data

We present new constraints on the non-linear coupling parameter fnl with the Wilkinson Microwave Anisotropy Probe (WMAP) data. We use an updated method based on the spherical Mexican hat wavelet (SMHW) which provides improved constraints on the fnl parameter. This paper is a continuation of a previous work by Curto et al. where several third order statistics based on the SMHW were considered. In this paper, we use all the possible third order statistics computed from the wavelet coefficient maps evaluated at 12 angular scales. The scales are logarithmically distributed from 6.9 arcmin to 500 arcmin. Our analysis indicates that fnl is constrained to -18 < fnl < +80 at 95% confidence level (CL) for the combined V+W WMAP map. This value has been corrected by the presence of undetected point sources, which adds a positive contribution of Delta_fnl = 6 +- 5. Our result excludes at ~99% CL the best-fitting value fnl=87 reported by Yadav & Wandelt. We have also constrained fnl for the Q, V and W frequency bands separately, finding compatibility with zero at 95 % CL for the Q and V bands but not for the W band. We have performed some further tests to understand the cause of this deviation which indicate that systematics associated to the W radiometers could be responsible for this result. Finally we have performed a Galactic North-South analysis for fnl. We have not found any asymmetry, i.e. the best-fitting fnl for the northern pixels is compatible with the best-fitting fnl for the southern pixels.Comment: 6 pages, 4 figures, 4 tables. Accepted for publication in Ap