On a generalised model for time-dependent variance with long-term memory

The ARCH process (R. F. Engle, 1982) constitutes a paradigmatic generator of stochastic time series with time-dependent variance like it appears on a wide broad of systems besides economics in which ARCH was born. Although the ARCH process captures the so-called "volatility clustering" and the asymptotic power-law probability density distribution of the random variable, it is not capable to reproduce further statistical properties of many of these time series such as: the strong persistence of the instantaneous variance characterised by large values of the Hurst exponent (H > 0.8), and asymptotic power-law decay of the absolute values self-correlation function. By means of considering an effective return obtained from a correlation of past returns that has a q-exponential form we are able to fix the limitations of the original model. Moreover, this improvement can be obtained through the correct choice of a sole additional parameter, $q_{m}$. The assessment of its validity and usefulness is made by mimicking daily fluctuations of SP500 financial index.Comment: 6 pages, 4 figure

Lipschütz ulcer and group A streptococcal tonsillitis

Lipschütz ulcers (LU) are non-sexually related genital ulcers, rarely reported. We describe a healthy 11-year-old girl, who presented with fever and a painful vulvar ulcer associated with erythematous tonsillitis. Throat swab test for Group A Streptococcus (GAS) was positive. She was treated with amoxicillin. Further investigation was negative, including Herpes Simplex virus DNA from ulcer swab and serology for Epstein-Barr virus, cytomegalovirus and Mycoplasma pneumoniae Antistreptolysin O titre was high. The ulcer healed in 2 weeks, with no recurrence in a 1 year follow-up period. The association of LU with GAS tonsillitis is very rare.info:eu-repo/semantics/publishedVersio

Disruption of ph dynamics suppresses proliferation and potentiates doxorubicin cytotoxicity in breast cancer cells

The reverse pH gradient is a major feature associated with cancer cell reprogrammed metabolism. This phenotype is supported by increased activity of pH regulators like ATPases, carbonic anhydrases (CAs), monocarboxylate transporters (MCTs) and sodium–proton exchangers (NHEs) that induce an acidic tumor microenvironment, responsible for the cancer acid-resistant phenotype. In this work, we analyzed the expression of these pH regulators and explored their inhibition in breast cancer cells as a strategy to enhance the sensitivity to chemotherapy. Expression of the different pH regulators was evaluated by immunofluorescence and Western blot in two breast cancer cell lines (MDA-MB-231 and MCF-7) and by immunohistochemistry in human breast cancer tissues. Cell viability, migration and invasion were evaluated upon exposure to the pH regulator inhibitors (PRIs) concanamycin-A, cariporide, acetazolamide and cyano-4-hydroxycinnamate. Additionally, PRIs were combined with doxorubicin to analyze the effect of cell pH dynamic disruption on doxorubicin sensitivity. Both cancer cell lines expressed all pH regulators, except for MCT1 and CAXII, only expressed in MCF-7 cells. There was higher plasma membrane expression of the pH regulators in human breast cancer tissues than in normal breast epithelium. Additionally, pH regulator expression was significantly associated with different molecular subtypes of breast cancer. pH regulator inhibition decreased cancer cell aggressiveness, with a higher effect in MDA-MB-231. A synergistic inhibitory effect was observed when PRIs were combined with doxorubicin in the breast cancer cell line viability. Our results support proton dynamic disruption as a breast cancer antitumor strategy and the use of PRIs to boost the activity of conventional therapy.This research was funded by National funds, through the Foundation for Science and Technology (FCT) - project UIDB/50026/2020 and UIDP/50026/2020; and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was also supported by an internal CESPU project MetabRes_CESPU_2017. DT-V received a fellowship from FCT (ref. SFRH/BD/103025/2014)

Impacto Alimentar Esofágico, um Dilema Diagnóstico

O impacto alimentar esofágico é uma situação que na maioria dos casos é secundária a patologia esofágica congénita ou adquirida, podendo constituir a primeira manifestação da doença. Descreve-se um rapaz, 11 anos, saudável, com sialorreia e dor retrosternal que surgiram subitamente durante o jantar. Foi submetido a endoscopia digestiva alta, que revelou um fragmento de carne impactado no terço distal do esófago (que foi extraído) e estrias longitudinais na mucosa. A análise histológica das biópsias esofágicas foi compatível com eosinofilia esofágica. Iniciou terapêutica com inibidor da bomba de protões com melhoria clínica e histológica. O diagnóstico diferencial das principais causas de impacto alimentar associadas a eosinofilia esofágica, nomeadamente esofagite eosinofílica, doença do refluxo gastroesofágico e eosinofilia esofágica respondedora a inibidor da bomba de protões, constitui um desafio clínico.info:eu-repo/semantics/publishedVersio

Statistical mixing and aggregation in Feller diffusion

We consider Feller mean-reverting square-root diffusion, which has been applied to model a wide variety of processes with linearly state-dependent diffusion, such as stochastic volatility and interest rates in finance, and neuronal and populations dynamics in natural sciences. We focus on the statistical mixing (or superstatistical) process in which the parameter related to the mean value can fluctuate - a plausible mechanism for the emergence of heavy-tailed distributions. We obtain analytical results for the associated probability density function (both stationary and time dependent), its correlation structure and aggregation properties. Our results are applied to explain the statistics of stock traded volume at different aggregation scales.Comment: 16 pages, 3 figures. To be published in Journal of Statistical Mechanics: Theory and Experimen

The role of the nature of the noise in the thermal conductance of mechanical systems

Focussing on a paradigmatic small system consisting of two coupled damped oscillators, we survey the role of the L\'evy-It\^o nature of the noise in the thermal conductance. For white noises, we prove that the L\'evy-It\^o composition (Lebesgue measure) of the noise is irrelevant for the thermal conductance of a non-equilibrium linearly coupled chain, which signals the independence between mechanical and thermodynamical properties. On the other hand, for the non-linearly coupled case, the two types of properties mix and the explicit definition of the noise plays a central role.Comment: 9 pages, 2 figures. To be published in Physical Review

Sexualidade no Terceiro Trimestre de Gravidez

Objectivos: Descrever a experiência sexual feminina no terceiro trimestre de gravidez. Tipo de estudo: Estudo descritivo transversal. Local: Consulta de Referência da Maternidade Dr. Alfredo da Costa – Lisboa, Portugal. População: Amostra de conveniência de cem mulheres com gravidez de baixo risco, que não tinham restrições médicas na sua actividade sexual. Métodos: As participantes completaram voluntariamente e em anonimato um questionário elaborado pelos autores respeitante a dados demográficos, história obstétrica, relacionamento sexual e esclarecimento/mitos sobre a sexualidade durante o último mês de gravidez. Resultados: A maioria das grávidas refere diminuição da actividade sexual após engravidar, embora mantenha relações sexuais uma ou mais vezes por semana e coito vaginal no terceiro trimestre, sem mudanças significativas para outros tipos de comportamento. Os factores que influenciam a redução da actividade sexual no terceiro trimestre são a diminuição do desejo, dispareunia e cansaço físico. Os mitos, crenças religiosas, nível de educação e dificuldade na informação sentida também parecem contribuir para a redução da actividade sexual. Frequentemente as grávidas indicam que o parceiro tem medo de prejudicar o bebé. Poucas mulheres obtiveram informação através dos profissionais de saúde sobre este tópico e consideram que gostariam de ter sido mais bem esclarecidas pelos mesmos. Conclusões: Os autores acreditam que na maioria dos casos a gravidez não provoca uma ruptura na sexualidade de um casal se esta era previamente satisfatória. No entanto, consideram importante a abordagem deste tema com a grávida por parte dos profissionais de saúde

Recognizing emotions through facial expressions: a largescale experimental study

Experimental research examining emotional processes is typically based on the observation of images with affective content, including facial expressions. Future studies will benefit from databases with emotion-inducing stimuli in which characteristics of the stimuli potentially influencing results can be controlled. This study presents Portuguese normative data for the identification of seven facial expressions of emotions (plus a neutral face), on the Radboud Faces Database (RaFD). The effect of participants' gender and models' sex on emotion recognition was also examined. Participants (N = 1249) were exposed to 312 pictures of white adults displaying emotional and neutral faces with a frontal gaze. Recognition agreement between the displayed and participants' chosen expressions ranged from 69% (for anger) to 97% (for happiness). Recognition levels were significantly higher among women than among men only for anger and contempt. The emotion recognition was higher either in female models or in male models depending on the emotion. Overall, the results show high recognition levels of the facial expressions presented, indicating that the RaFD provides adequate stimuli for studies examining the recognition of facial expressions of emotion among college students. Participants' gender had a limited influence on emotion recognition, but the sex of the model requires additional consideration