Temperature influence and social interaction on the frequency of electric organ discharges in Rhamphicthys rostratus.

The frequency of electric organ discharges (EOD) of a gymnotiform fish of "pulse" frequency (40-100 Hz) from South America - Ramphicthys rostratuswas studied. The animals were settled in pairs in a aquarium and thus observed: variation in EOD frequency had at least two components: one more positively correlated with temperature, another less positively correlated due to social interaction.

Frequency-domain receiver design for doubly-selective channels

This work is devoted to the broadband wireless transmission techniques, which are serious candidates to be implemented in future broadband wireless and cellular systems, aiming at providing high and reliable data transmission and concomitantly high mobility. In order to cope with doubly-selective channels, receiver structures based on OFDM and SC-FDE block transmission techniques, are proposed, which allow cost-effective implementations, using FFT-based signal processing. The first subject to be addressed is the impact of the number of multipath components, and the diversity order, on the asymptotic performance of OFDM and SC-FDE, in uncoded and for different channel coding schemes. The obtained results show that the number of relevant separable multipath components is a key element that influences the performance of OFDM and SC-FDE schemes. Then, the improved estimation and detection performance of OFDM-based broadcasting systems, is introduced employing SFN (Single Frequency Network) operation. An initial coarse channel is obtained with resort to low-power training sequences estimation, and an iterative receiver with joint detection and channel estimation is presented. The achieved results have shown very good performance, close to that with perfect channel estimation. The next topic is related to SFN systems, devoting special attention to time-distortion effects inherent to these networks. Typically, the SFN broadcast wireless systems employ OFDM schemes to cope with severely time-dispersive channels. However, frequency errors, due to CFO, compromises the orthogonality between subcarriers. As an alternative approach, the possibility of using SC-FDE schemes (characterized by reduced envelope fluctuations and higher robustness to carrier frequency errors) is evaluated, and a technique, employing joint CFO estimation and compensation over the severe time-distortion effects, is proposed. Finally, broadband mobile wireless systems, in which the relative motion between the transmitter and receiver induces Doppler shift which is different or each propagation path, is considered, depending on the angle of incidence of that path in relation to the direction of travel. This represents a severe impairment in wireless digital communications systems, since that multipath propagation combined with the Doppler effects, lead to drastic and unpredictable fluctuations of the envelope of the received signal, severely affecting the detection performance. The channel variations due this effect are very difficult to estimate and compensate. In this work we propose a set of SC-FDE iterative receivers implementing efficient estimation and tracking techniques. The performance results show that the proposed receivers have very good performance, even in the presence of significant Doppler spread between the different groups of multipath components.

Quantitative Centromere Epigenetics

A PhD is like a box of chocolates, …… and in this thesis I will present what I got. My work has been focused on a cellular structure that is essential for accurate genome inheritance: the centromere. Centromeres are chromosomal domains that do not rely on the presence of any specific DNA sequence. Rather, they are determined by the presence of a histone variant called CENP-A. Stable transmission of CENP-A containing chromatin is accomplished through 1) an unusually high level of protein stability, 2) selfdirected recruitment of nascent CENP-A near existing molecules, and 3) strict cell cycle regulation of assembly. Together, these features lead to a self-sustaining loop that allows for epigenetic maintenance of centromeres.(...)

The role of arl13b in cilia length regulation and in zebrafish development

RESUMO: Arl13b é uma importante proteína ciliar, presente em cílios primários e cílios móveis. Ratinhos mutantes para Arl13b têm comprimento dos cílios reduzido e defeitos nos B-túbulos dos cílios. Como consequência destes fenótipos, deficiências na Arl13b originam, em modelos animais, várias doenças congénitas, incluindo problemas no estabelecimento do eixo esquerda-direita, malformações cerebrais e deformações corporais. Nos seres humanos, deficiências na Arl13b levam a uma doença crónica congénita chamada Síndrome de Joubert. Por outro lado, a sobreexpressão de Arl13b origina cílios mais longos, no entanto existe uma ausência da caracterização dos fenótipos celulares e durante o desenvolvimento embrionário. Neste trabalho, quisemos explorar o efeito da sobre-expressão de Arl13b em embriões de peixezebra. Descobrimos que, ao nível ciliar, a sobre-expressão de Arl13b nas células aumenta o comprimento ciliar em cílios primários e móveis, no entanto, a esses cílios falta adequada acetilação da alfa-tubulina no citoesqueleto feito por microtúbulos. Os nossos resultados mostraram que esse efeito é específico de Arl13b sobre-expressão e quando se manipularam as enzimas responsáveis pela acetilação (Mec17) e pela de-acetilação (HDAC6) encontrámos uma sinergia potencial com ambas. Testámos ainda, que o aumento no comprimento ciliar não estava causalmente relacionado com a falta de acetilação, ou seja, os cílios com menos acetilação não eram necessariamente os mais longos. Também mostrámos que a sobre-expressão de Arl13b é capaz de restaurar o comprimento dos cílios em mutantes com cílios curtos e como isso pode ser explorado para um futuro potencial papel terapêutico para Arl13b. Em seguida, foi avaliado o impacto do aumento da quantidade de Arl13b no desenvolvimento embrionário do peixe-zebra. Observou-se que a sobre-expressão de Arl13b apresentava fenótipos muito fracos, quando comparados com a perda de função dos mutantes de Arl13b. Focados no inesperado fenótipo leve no estabelecimento do eixo esquerda-direita abordámos a questão através do estabelecimento de uma colaboração com matemáticos, descobrimos que os cílios mais longos que potencialmente têm a capacidade de movimentar mais fluido são atenuados por amplitudes de batimento menores, e, como resultado, estes longos cílios não prejudicam o movimento do fluido e consequentemente não afetam o estabelecimento dos padrões de esquerda-direita. Sugerimos assim que a Arl13b é um regulador chave, do comprimento ciliar. Descobrimos uma nova interação com as enzimas de acetilação/de-acetilação e levantamos novas hipóteses quanto aos mecanismos moleculares da função da Arl13b. Propomos um novo modelo para o mecanismo molecular da Arl13b na regulação do comprimento dos cílios onde podemos integrar os nossos resultados com os relatados na literatura. Este trabalho adiciona mais conhecimento para o mecanismo de ação da Arl13b e, portanto, fornece uma importante contribuição para o campo da investigação em cílios.---------------------------------------------------------------------------------------------------------------------- ABSTRACT: Arl13b is an important ciliary protein, present in primary and motile cilia. arl13b-/- mouse mutants have reduced cilia length and cilia B-tubule defects. As a consequence of these phenotypes, Arl13b loss of function animal models suffer from several congenital disorders including left-right problems, brain malformations and body deformations. In humans Arl13b depletion leads to a congenital chronic disease called Joubert Syndrome. On the other hand, overexpressing Arl13b leads to longer cilia but the characterization of the cellular and developmental phenotypes was missing. In this work we explore the effect of Arl13b overexpression in zebrafish embryos. We found that, at the ciliary level, Arl13b overexpression from 1 cell stage produces longer primary and motile cilia, but these cilia lack proper alpha tubulin acetylation of their microtubule cytoskeleton. Our results showed that this effect is specific from Arl13b overexpression and when we manipulated the enzymes responsible for acetylation, Mec17, and de-acetylation, HDAC6, we found a potential synergy of both mec17 knockdown and HDAC6 activity with Arl13b overexpression. We tested that the ciliary increase in length was not causally related to the lack of acetylation, meaning the more de-acetylated cilia were not necessarily the longer ones. We also showed that Arl13b overexpression is able to restore cilia length in short cilia mutants and how that may be explored to a potential future therapeutic role for Arl13b. Next, we evaluated the impact of increasing the amount of Arl13b in zebrafish embryonic development. We observed that Arl13b overexpression presented very mild phenotypes when compared to the loss of function mutants. We focused on the unexpected left-right mild phenotype and by establishing a mathematical modeling collaboration, we found out that the longer cilia generated force was attenuated by smaller beating amplitudes, and as a result, these long cilia were not impairing the cilia generated flow and the establishment of left-right patterning. We suggest that Arl13b is one key cilia length regulator. We disclosed a novel interaction with the acetylation / de-acetylation enzymes and raised new hypothesis as to the mechanisms of Arl13b function. We propose a new model for the Arl13b molecular mechanism of cilia length regulation where we integrate our findings with those reported in the literature. This work adds more knowledge to the Arl13b mechanism of action and therefore provides an important contribution to the cilia research field.

The influence of low-frequency noise pollution on the quality of life and place in sustainable cities: a case study from northern Portugal

Discussing urban planning requires rethinking sustainability in cities and building healthy environments. Historically, some aspects of advancing the urban way of life have not been considered important in city planning. This is particularly the case where technological advances have led to conflicting land use, as with the installation of power poles and building electrical substations near residential areas. This research aims to discuss and rethink sustainability in cities, focusing on the environmental impact of low-frequency noise and electromagnetic radiation on human health. It presents data from a case study in an urban space in northern Portugal, and focuses on four guiding questions: Can power poles and power lines cause noise? Do power poles and power lines cause discomfort? Do power poles and power lines cause discomfort due to noise? Can power poles and power lines affect human health? To answer these questions, we undertook research between 2014 and 2015 that was comprised of two approaches. The first approach consisted of evaluating the noise of nine points divided into two groups â near the sourceâ (e.g., up to 50 m from power poles) and â away from the sourceâ (e.g., more than 250 m away from the source). In the second approach, noise levels were measured for 72 h in houses located up to 20 m from the source. The groups consist of residents living within the distance range specified for each group. The measurement values were compared with the proposed criteria for assessing low-frequency noise using the DEFRA Guidance (University of Salford). In the first approach, the noise caused discomfort, regardless of the group. In the second approach, the noise had fluctuating characteristics, which led us to conclude that the noise caused discomfort.

Equity offerings, stock price crash risk, and the impact of securities regulation: international evidence

We examine whether earnings manipulation around seasoned equity offerings (SEOs) is associated with an increase in the likelihood of a stock price crash post-issue and test whether the enactment of securities regulations attenuate the relation between SEOs and crash risk. Empirical evidence documents that managerial tendency to conceal bad news increases the likelihood of a stock price crash (Jin and Myers, 2006; Hutton, Marcus, and Tehranian, 2009). We test this hypothesis using a sample of firms from 29 EU countries that enacted the Market Abuse Directive (MAD). Consistent with our hypothesis, we find that equity issuers that engage in earnings management experience a significant increase in crash risk post-SEO relative to control groups of non-issuers; this effect is stronger for equity issuers with poor information environments. In addition, our findings show a significant decline in crash risk post-issue after the enactment of MAD that is stronger for firms that actively manage earnings. This decline in post-issue crash risk is more effective in countries with high ex-ante institutional quality and enforcement. These results suggest that the implementation of MAD helps to mitigate managers’ ability to manipulate earnings around SEOs.

Hair coloration by gene regulation: fact or fiction?

The unravelling of hair pigmentation genetics and robust delivery systems to the hair follicle (HF) will allow the development of a new class of colouring products. The challenge will be changing hair colour from inside out by safely regulating the activity of target genes through the specific delivery of synthetic/natural compounds, proteins, genes, or small RNAs.

Pharmaceutical regulation and pseudo - generics

Dissertação de mestrado em Economia Industrial e da Empresa

Hemispheric dorsolateral prefrontal cortex lateralization in the regulation of empathy for pain

The dorsolateral prefrontal cortex (DLPFC) is involved in the cognitive appraisal and modulation of the pain experience. In this sham-controlled study, with healthy volunteers, we used bi-hemispheric transcranial direct current stimulation (tDCS) over the DLPFC to assess emotional reactions elicited by pain observation. Left-cathodal/right-anodal tDCS decreased valence and arousal evaluations compared to other tDCS conditions. Compared to sham condition, both left-cathodal/right-anodal and left-anodal/right-cathodal tDCS decreased hostility, sadness and self-pain perception. These decreased sensations after both active tDCS suggest a common role for left and right DLPFC in personal distress modulation. However, the differences in arousal and valence evaluations point to distinct roles of lateralized DLPFC in cognitive empathy, probably through distinct emotion regulation mechanisms.

Challenges and confusion in media regulation: a four-country comparison

[Excerto] ln this chapter we discuss recent developments and challenges in European media and communication policy, focusing on the period following the 2008 global financial crisis. We are especially interested in the implications of the financial crisis and its political repercussions nationally (austerity measures and cuts to public services, growing anti-politics sentiments and widespread dissatisfaction with free-market capitalism and representative democracy) for media and communication policy, understood here in a broad sense, so as to include ali electronic communications, such as the Internet, mobile communications, social media etc. Our overarching concern is with the implications of developments in media and communication policy for the democratic functions of the media in Europe (...).

Molecular regulation of flowering induction in Quercus suber

Dissertação de mestrado em Plant Molecular Biology, Biotechnology and Bioentrepeneurship

Low frequency of TERT promoter mutations in gastrointestinal stromal tumors (GISTs).

Somatic mutations in the promoter region of telomerase reverse transcriptase (TERT) gene, mainly at positions c. − 124 and c. − 146 bp, are frequent in several human cancers; yet its presence in gastrointestinal stromal tumor (GIST) has not been reported to date. Herein, we searched for the presence and clinicopathological association of TERT promoter mutations in genomic DNA from 130 bona fide GISTs. We found TERT promoter mutations in 3.8% (5/130) of GISTs. The c. − 124C4T mutation was the most common event, present in 2.3% (3/130), and the c. − 146C4T mutation in 1.5% (2/130) of GISTs. No significant association was observed between TERT promoter mutation and patient’s clinicopathological features. The present study establishes the low frequency (4%) of TERT promoter mutations in GISTs. Further studies are required to confirm our findings and to elucidate the hypothetical biological and clinical impact of TERT promoter mutation in GIST pathogenesis.

Regulation of human mesenchymal stem cell osteogenesis by specific surface density of fibronectin: a gradient study

 The success of synthetic bone implants requires good interface between the material and the host tissue. To study the biological relevance of fi bronectin (FN) density on the osteogenic commitment of human bone marrow mesenchymal stem cells (hBMMSCs), human FN was adsorbed in a linear density gradient on the surface of PCL. The evolution of the osteogenic markers alkaline phosphatase and collagen 1 alpha 1 was monitored by immunohistochemistry, and the cytoskeletal organization and the cell-derived FN were assessed. The functional analysis of the gradient revealed that the lower FN-density elicited stronger osteogenic expression and higher cytoskeleton spreading, hallmarks of the stem cell commitment to the osteoblastic lineage. The identifi cation of the optimal FN density regime for the osteogenic commitment of hBM-MSCs presents a simple and versatile strategy to signifi cantly enhance the surface properties of polycaprolactone as a paradigm for other synthetic polymers intended for bone-related applications.