Estimation in the group action channel

We analyze the problem of estimating a signal from multiple measurements on a \mbox{group action channel} that linearly transforms a signal by a random group action followed by a fixed projection and additive Gaussian noise. This channel is motivated by applications such as multi-reference alignment and cryo-electron microscopy. We focus on the large noise regime prevalent in these applications. We give a lower bound on the mean square error (MSE) of any asymptotically unbiased estimator of the signal's orbit in terms of the signal's moment tensors, which implies that the MSE is bounded away from 0 when $N/\sigma^{2d}$ is bounded from above, where $N$ is the number of observations, $\sigma$ is the noise standard deviation, and $d$ is the so-called \mbox{moment order cutoff}. In contrast, the maximum likelihood estimator is shown to be consistent if $N /\sigma^{2d}$ diverges.Comment: 5 pages, conferenc

Multiscale Fractal Descriptors Applied to Nanoscale Images

This work proposes the application of fractal descriptors to the analysis of nanoscale materials under different experimental conditions. We obtain descriptors for images from the sample applying a multiscale transform to the calculation of fractal dimension of a surface map of such image. Particularly, we have used the}Bouligand-Minkowski fractal dimension. We applied these descriptors to discriminate between two titanium oxide films prepared under different experimental conditions. Results demonstrate the discrimination power of proposed descriptors in such kind of application

Characterization of nanostructured material images using fractal descriptors

This work presents a methodology to the morphology analysis and characterization of nanostructured material images acquired from FEG-SEM (Field Emission Gun-Scanning Electron Microscopy) technique. The metrics were extracted from the image texture (mathematical surface) by the volumetric fractal descriptors, a methodology based on the Bouligand-Minkowski fractal dimension, which considers the properties of the Minkowski dilation of the surface points. An experiment with galvanostatic anodic titanium oxide samples prepared in oxalyc acid solution using different conditions of applied current, oxalyc acid concentration and solution temperature was performed. The results demonstrate that the approach is capable of characterizing complex morphology characteristics such as those present in the anodic titanium oxide.Comment: 8 pages, 5 figures, accepted for publication Physica

Impact of parental cancer in offspring’s psychological development: literature review

O presente artigo engloba uma extensa revisão da literatura sobre a temática do câncer parental e as consequências pessoais e familiares desta vivência. Nesse sentido, são abordadas as principais consequências médicas e psicossociais do diagnóstico e tratamento do câncer e, usando o modelo sistémico, é descrita a influência (negativa e positiva) deste acontecimento no doente e noutros membros da família. É dado especial enfoque ao desenvolvimento psicológico dos filhos, incluindo os resultados dos estudos referentes ao stress traumático e crescimento pós-traumático, em particular no câncer da mama. São tecidas algumas implicações para a investigação nesta área, bem como sugestões para futuras investigações.The present paper includes an extended literature review about parental cancer and personal and family consequences of such experience. Some of the most important medical and psychosocial issues regarding the diagnosis and treatment of parental cancer are presented. Using a systemic theory as the background model it addresses the influences (negative and positive) of the event in the patient and in other family members. The present paper gives special focus on the offspring’s psychological development, including the results regarding traumatic stress and posttraumatic growth, particularly on breast cancer. Some implications and suggestions for future research are addressed.Fundação para a Ciência e a Tecnologia (FCT

Recovery of valuable aromas from sardine cooking wastewaters by pervaporation with fractionated condensation: matrix effect and model validation

Due to the lack of studies addressing the influence of real food matrices on integrated organophilic pervaporation/fractionated condensation processes, the present work analyses the impact of the real matrix of sardine cooking wastewaters on the fractionation of aromas. In a previous study, a thermodynamic/material balance model was developed to describe the integrated pervaporation—a fractionated condensation process of aroma recovery from model solutions that emulate seafood industry aqueous effluents, aiming to define the best conditions for off-flavour removal. This work assesses whether the previously developed mathematical model, validated only with model solutions, is also applicable in predicting the fractionation of aromas of different chemical families from real effluents (sardine cooking wastewaters), aiming for off-flavour removals. It was found that the food matrix does not influence substantial detrimental consequences on the model simulations, which validates and extends the applicability of the model.info:eu-repo/semantics/publishedVersio

On the nature of the (de)coupling of the magnetostructural transition in Er5_5Si4_4

In this report, a successful thermodynamical model was employed to understand the structural transition in Er$_5$Si$_4$, able to explain the decoupling of the magnetic and structural transition. This was achieved by the DFT calculations which were used to determine the energy differences at 0 K, using a LSDA+U approximation. It was found that the M structure as the stable phase at low temperatures as verified experimentally with a $\Delta F_0 = -$0.262 eV. Finally, it was achieved a variation of Seebeck coefficient ($\sim$ 6 $\mu$V) at the structural transition which allow to conclude that the electronic entropy variation is negligible in the transition.Comment: 17 pages, 3 figures, 1 tabl

Active methodologies in incoming programming classes

Innovative approaches in teaching programming have been required to improve the success of incoming programming students. This work presents the initial results of a teaching strategy implemented in the Algorithms subject of a Computer Science course. Ninety-five students, enrolled in this subject during the first semester of the course, participated in the research. The reported activity is related with active methodologies of teaching and Problem-Based Learning, being developed on the first day of class in groups of up to five students. The activity was based in two actions: 1) answering a questionnaire associating computing elements to daily life routines; and, 2) even without programming concepts knowledge, develop a smartphone application. Each group received a questionnaire containing 19 questions, divided into four blocks. What can be perceived with the accomplishment of this work, was the enthusiasm, motivation and engagement of the students who, even being unknown from each other, organized themselves in the groups and researched the necessary strategies to complete the challenge. The teacher acted as an advisor in the teaching process, conducting the experiment in order to lead students to find the solution.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Projects Scopes: UIDB/05757/2020 and UIDB/00319/2020.info:eu-repo/semantics/publishedVersio