Silvia Lopes - Academia.edu (original) (raw)
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Skolkovo Institute of Science and Technology
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Papers by Silvia Lopes
Communications in Statistics - Simulation and Computation, 2014
Bayesian inference for fractionally integrated exponential generalized autoregressive conditional... more Bayesian inference for fractionally integrated exponential generalized autoregressive conditional heteroskedastic (FIEGARCH) models using Markov Chain Monte Carlo (MCMC) methods is described. A simulation study is presented to access the performance of the procedure, under the presence of long-memory in the volatility. Samples from FIEGARCH processes are obtained upon considering the generalized error distribution (GED) for the innovation process. Different values for the tail-thickness parameter ν are considered covering both scenarios, innovation processes with lighter (ν < 2) and heavier (ν > 2) tails than the Gaussian distribution (ν = 2). A sensitivity analysis is performed by considering different prior density functions and by integrating (or not) the knowledge on the true parameter values to select the hyperparameter values.
European Journal of Organic Chemistry, 2012
A series of rosamine fluorophores was obtained by reaction of the appropriate benzaldehyde and 3-... more A series of rosamine fluorophores was obtained by reaction of the appropriate benzaldehyde and 3-(diethylamino)phenol followed by an oxidation step. Both conventional heating and microwave irradiation methods were utilized, and higher yields in a remarkably shorter period of time (10 min) were achieved by using the microwave irradiation protocol under closed vessel conditions (80°C). The nitro-substituted rosamine was further converted into the corresponding amino derivative through Pd/C-catalysed hydrogenation. The synthetic protocol used for rosamines was also successfully employed to synthesise naphthyl analogues by using 1-and 2naphthaldehyde. In the latter case, a novel hydroxy analogue was also obtained as a minor product. The photophysical be-[a] REQUIMTE,
Dyes and Pigments, 2012
... Carla Queirós 1 , Ana MG Silva 2 , Corresponding Author Contact Information , E-mail The Corr... more ... Carla Queirós 1 , Ana MG Silva 2 , Corresponding Author Contact Information , E-mail The Corresponding Author , Sílvia C. Lopes 2 , Galya Ivanova 2 , Paula Gameiro 2 , Maria Rangel 1 , Corresponding Author Contact Information , E-mail The Corresponding Author. ...
FEMS Microbiology Ecology, 2012
Stoch. Dyn, 2002
In this work we analyze the convergence in distribution sense of the periodogram function (to the... more In this work we analyze the convergence in distribution sense of the periodogram function (to the spectral density function) based on a time series of a stationary process X t = (ϕ • T t )(X 0 ) obtained from the iterations of a continuous transformation T invariant for an ergodic probability µ and a continuous function ϕ taking values in R. We only assume a certain rate of convergence to zero for the autocovariance coefficient of the stochastic process, that is, we assume there exist C > 0 and ) 2 is the h-autocovariance of the process. Our result applies to the case of exponential decay of correlation (or covariance), as it happens for a continuous expanding transformation T on the circle and a Holder potential ϕ. It can also be applied to the case when the transformation T has a fixed point with derivative equal to one.
Health information and libraries journal, 2012
This is the fourth in a series of articles exploring international trends in health science libra... more This is the fourth in a series of articles exploring international trends in health science librarianship in four Southern European countries in the first decade of the 21st century. The invited authors are from Greece, Italy, Spain and Portugal. Future issues will track trends in Latin America and Central Europe.
Communications in Statistics - Simulation and Computation, 2014
Bayesian inference for fractionally integrated exponential generalized autoregressive conditional... more Bayesian inference for fractionally integrated exponential generalized autoregressive conditional heteroskedastic (FIEGARCH) models using Markov Chain Monte Carlo (MCMC) methods is described. A simulation study is presented to access the performance of the procedure, under the presence of long-memory in the volatility. Samples from FIEGARCH processes are obtained upon considering the generalized error distribution (GED) for the innovation process. Different values for the tail-thickness parameter ν are considered covering both scenarios, innovation processes with lighter (ν < 2) and heavier (ν > 2) tails than the Gaussian distribution (ν = 2). A sensitivity analysis is performed by considering different prior density functions and by integrating (or not) the knowledge on the true parameter values to select the hyperparameter values.
European Journal of Organic Chemistry, 2012
A series of rosamine fluorophores was obtained by reaction of the appropriate benzaldehyde and 3-... more A series of rosamine fluorophores was obtained by reaction of the appropriate benzaldehyde and 3-(diethylamino)phenol followed by an oxidation step. Both conventional heating and microwave irradiation methods were utilized, and higher yields in a remarkably shorter period of time (10 min) were achieved by using the microwave irradiation protocol under closed vessel conditions (80°C). The nitro-substituted rosamine was further converted into the corresponding amino derivative through Pd/C-catalysed hydrogenation. The synthetic protocol used for rosamines was also successfully employed to synthesise naphthyl analogues by using 1-and 2naphthaldehyde. In the latter case, a novel hydroxy analogue was also obtained as a minor product. The photophysical be-[a] REQUIMTE,
Dyes and Pigments, 2012
... Carla Queirós 1 , Ana MG Silva 2 , Corresponding Author Contact Information , E-mail The Corr... more ... Carla Queirós 1 , Ana MG Silva 2 , Corresponding Author Contact Information , E-mail The Corresponding Author , Sílvia C. Lopes 2 , Galya Ivanova 2 , Paula Gameiro 2 , Maria Rangel 1 , Corresponding Author Contact Information , E-mail The Corresponding Author. ...
FEMS Microbiology Ecology, 2012
Stoch. Dyn, 2002
In this work we analyze the convergence in distribution sense of the periodogram function (to the... more In this work we analyze the convergence in distribution sense of the periodogram function (to the spectral density function) based on a time series of a stationary process X t = (ϕ • T t )(X 0 ) obtained from the iterations of a continuous transformation T invariant for an ergodic probability µ and a continuous function ϕ taking values in R. We only assume a certain rate of convergence to zero for the autocovariance coefficient of the stochastic process, that is, we assume there exist C > 0 and ) 2 is the h-autocovariance of the process. Our result applies to the case of exponential decay of correlation (or covariance), as it happens for a continuous expanding transformation T on the circle and a Holder potential ϕ. It can also be applied to the case when the transformation T has a fixed point with derivative equal to one.
Health information and libraries journal, 2012
This is the fourth in a series of articles exploring international trends in health science libra... more This is the fourth in a series of articles exploring international trends in health science librarianship in four Southern European countries in the first decade of the 21st century. The invited authors are from Greece, Italy, Spain and Portugal. Future issues will track trends in Latin America and Central Europe.