FIA potentiometric system based on periodate polymeric membrane sensors for the assessment of ascorbic acid in commercial drinks

Ascorbic acid is found in many food samples. Its clinical and technological importance demands an easyto- use, rapid, robust and inexpensive method of analysis. For this purpose, this work proposes a new flow procedure based on the oxidation of ascorbic acid by periodate. A new potentiometric periodate sensor was constructed to monitor this reaction. The selective membranes were of PVC with porphyrin-based sensing systems and a lipophilic cation as additive. The sensor displayed a near-Nernstian response for periodate over 1.0x10-2–6.0x10-6 M, with an anionic slope of 73.9 ± 0.9 mV decade-1. It was pH independent in acidic media and presented good selectivity features towards several inorganic anions. The flow set-up operated in double-channel, carrying a 5.0x10-4 M IO- 4 solution and a suitable buffer; these were mixed in a 50-cm reaction coil. The overall flow rate was 7 ml min-1 and the injection volume 70 µl. Under these conditions, a linear behaviour against concentration was observed for 17.7–194.0 µg ml-1, presenting slopes of 0.169 mV (mg/l)-1, a reproducibility of ±1.1 mV (n = 5), and a sampling rate of ~96 samples h-1. The proposed method was applied to the analysis of beverages and pharmaceuticals.

A cultura na primeira página: a relação entre media, agentes culturais e públicos

Os jornais não acompanham o movimento de descentralização cultural iniciado na última década do séc. XX e descuida a programação realizada nos equipamentos espalhados um pouco por todo o país e pelos diversos grupos artísticos e culturais a desenvolver o seu trabalho fora de Lisboa. Que estratégias têm seguido esses equipamentos para contornar esta situação, para ganhar visibilidade de outras formas. Sabendo que a imprensa tem um papel importante ao incitar à ação e em formar opiniões e atitudes sobre os assuntos, aposta-se na imprensa regional e em meios cuja produção e atualização depende das próprias estruturas, nomeadamente sites e presença nas redes sociais. No entanto, se se quer atrair visitantes de fora da região, a imprensa continua a conseguir fixar o interesse e trazer público, menor é o papel que desempenha junto dos residentes. Levar os residentes a participar é algo que passa por outras estratégias de comunicação que não a imprensa nacional, e é nessas estratégias que muitas vezes os responsáveis por estas estruturas se centram, desenvolvendo e promovendo outras fontes de experiência.

Quais os motivos do insucesso de algumas crianças na aprendizagem musical? Motivação e Flow Theory

Este artigo aborda a natureza da motivação na sua relação com a aprendizagem musical. Um dos objectivos principais é problematizar a questão das diferenças no sucesso da aprendizagem musical quando nos encontramos perante indivíduos com níveis aparentemente semelhantes de capacidade e potencial musicais. Começa por apresentar um conjunto de modelos teóricos que oferecem uma visão acerca das razões que podem explicar as variações e mudanças na motivação. Refere-se investigação recente que sugere que os processos motivacionais não são pré-determinados mas podem ser aprendidos e que os indivíduos, para atingir níveis elevados de sucesso, necessitam de uma focagem no processo por oposição a uma focagem no produto. São introduzidos e explorados processos cognitivos fundamentais relacionados com a aprendizagem musical (por exemplo, comportamento au to-regulado, papel da motivação intrínseca e extrínseca) . Como conclusão, sugerem-se algumas práticas específicas para que os professores possam reflectir acerca da melhor forma de encorajar e aumentar a motivação dos seus alunos para aprender música.

Revista Media e Jornalismo: Imagens e Jornalismo

Número dedicado à reflexão sobre o papel das imagens visuais no jornalismo contemporâneo. Os contributos dos diferentes autores aqui publicados permitem confirmar a importância de imagem como objeto de estudo, sobretudo no campo jornalístico, onde o seu potencial enquanto meio e linguagem continua a nortear as discussões.

Endothelialization of chitosan porous conduits via immobilization of a recombinant fibronectin fragment (rhFNIII7–10)

The present study aimed to develop a pre-endothelialized chitosan (CH) porous hollowed scaffold for application in spinal cord regenerative therapies. CH conduits with different degrees of acetylation (DA; 4% and 15%) were prepared, characterized (microstructure, porosity and water uptake) and functionalized with a recombinant fragment of human fibronectin (rhFNIII7–10). Immobilized rhFNIII7–10 was characterized in terms of amount (125I-radiolabelling), exposure of cell-binding domains (immunofluorescence) and ability to mediate endothelial cell (EC) adhesion and cytoskeletal rearrangement. Functionalized conduits revealed a linear increase in immobilized rhFNIII7–10 with rhFNIII7–10 concentration, and, for the same concentration, higher amounts of rhFNIII7–10 on DA 4% compared with DA 15%. Moreover, rhFNIII7–10 concentrations as low as 5 and 20 lgml 1 in the coupling reaction were shown to provide DA 4% and 15% scaffolds, respectively, with levels of exposed cell-binding domains exceeding those observed on the control (DA 4% scaffolds incubated in a 20 lgml 1 human fibronectin solution). These grafting conditions proved to be effective in mediating EC adhesion/cytoskeletal organization on CH with DA 4% and 15%, without affecting the endothelial angiogenic potential. rhFNIII7–10 grafting to CH could be a strategy of particular interest in tissue engineering applications requiring the use of endothelialized porous matrices with tunable degradation rates.

Subacute effects of the thiodicarb pesticide on target organs of male wistar rats: biochemical, histological, and flow cytometry studies

Thiodicarb, a carbamate pesticide widely used on crops, may pose several environmental and health concerns. This study aimed to explore its toxicological profile on male rats using hematological, biochemical, histopathological, and flow cytometry markers. Exposed animals were dosed daily at 10, 20, or 40 mg/kg/body weight (group A, B, and C, respectively) during 30 d. No significant changes were observed in hematological parameters among all groups. After 10 d, a decrease of total cholesterol levels was noted in rats exposed to 40 mg/kg. Aspartate aminotransferase (AST) activity increased (group A at 20 d; groups A and B at 30 d) and alkaline phosphatase (ALP) (group B at 30 d) activity significantly reduced. At 30 d a decrease of some of the other evaluated parameters was observed with total cholesterol and urea levels in group A as well as total protein and creatinine levels in groups A and B. Histological results demonstrated multi-organ dose-related damage in thiodicarb-exposed animals, evidenced as hemorrhagic and diffuse vacuolation in hepatic tissue; renal histology showed disorganized glomeruli and tubular cell degeneration; spleen was ruptured with white pulp and clusters of iron deposits within red pulp; significant cellular loss was noted at the cortex of thymus; and degenerative changes were observed within testis. The histopathologic alterations were most prominent in the high-dose group. Concerning flow cytometry studies, an increase of lymphocyte number, especially T lymphocytes, was seen in blood samples from animals exposed to the highest dose. Taken together, these results indicate marked systemic organ toxicity in rats after subacute exposure to thiodicarb.

Systems of Navier-Stokes equations on cantor sets

We present systems of Navier-Stokes equations on Cantor sets, which are described by the local fractional vector calculus. It is shown that the results for Navier-Stokes equations in a fractal bounded domain are efficient and accurate for describing fluid flow in fractal media.

Futuro dos media passa pelas marcas

Na Escola Superior de Comunicação Social (ESCS), em Lisboa, o jornalismo, a publicidade, o marketing e as relações públicas não estão em crise, É que, todos os anos, há sempre dez vezes mais candidatos do que vagas. Jorge Veríssimo, presidente da instituição, diz que a componente tecnológica e o ambiente profissional são o segredo de uma escola que tornou obrigatória uma cadeira de Empreendedorismo. Sobre o futuro dos media, diz oque passa cada vez mais por uma interligação entre jornalismo e marcas.

A proposal for media component brokerage

This paper describes how MPEG-4 object based video (obv) can be used to allow selected objects to be inserted into the play-out stream to a specific user based on a profile derived for that user. The application scenario described here is for personalized product placement, and considers the value of this application in the current and evolving commercial media distribution market given the huge emphasis media distributors are currently placing on targeted advertising. This level of application of video content requires a sophisticated content description and metadata system (e.g., MPEG-7). The scenario considers the requirement for global libraries to provide the objects to be inserted into the streams. The paper then considers the commercial trading of objects between the libraries, video service providers, advertising agencies and other parties involved in the service. Consequently a brokerage of video objects is proposed based on negotiation and trading using intelligent agents representing the various parties. The proposed Media Brokerage Platform is a multi-agent system structured in two layers. In the top layer, there is a collection of coarse grain agents representing the real world players – the providers and deliverers of media contents and the market regulator profiler – and, in the bottom layer, there is a set of finer grain agents constituting the marketplace – the delegate agents and the market agent. For knowledge representation (domain, strategic and negotiation protocols) we propose a Semantic Web approach based on ontologies. The media components contents should be represented in MPEG-7 and the metadata describing the objects to be traded should follow a specific ontology. The top layer content providers and deliverers are modelled by intelligent autonomous agents that express their will to transact – buy or sell – media components by registering at a service registry. The market regulator profiler creates, according to the selected profile, a market agent, which, in turn, checks the service registry for potential trading partners for a given component and invites them for the marketplace. The subsequent negotiation and actual transaction is performed by delegate agents in accordance with their profiles and the predefined rules of the market.

B2B platform for media content personalisation

This paper proposes a novel business model to support media content personalisation: an agent-based business-to-business (B2B) brokerage platform for media content producer and distributor businesses. Distributors aim to provide viewers with a personalised content experience and producers wish to en-sure that their media objects are watched by as many targeted viewers as possible. In this scenario viewers and media objects (main programmes and candidate objects for insertion) have profiles and, in the case of main programme objects, are annotated with placeholders representing personalisation opportunities, i.e., locations for insertion of personalised media objects. The MultiMedia Brokerage (MMB) platform is a multiagent multilayered brokerage composed by agents that act as sellers and buyers of viewer stream timeslots and/or media objects on behalf of the registered businesses. These agents engage in negotiations to select the media objects that best match the current programme and viewer profiles.

Campanha de comunicação de Ambient Media para a marca Leroy Merlin

Trabalho de projeto apresentado à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.

Networked embedded systems for active flow control in aircraft

Aerodynamic drag is known to be one of the factors contributing more to increased aircraft fuel consumption. The primary source of skin friction drag during flight is the boundary layer separation. This is the layer of air moving smoothly in the immediate vicinity of the aircraft. In this paper we discuss a cyber-physical system approach able of performing an efficient suppression of the turbulent flow by using a dense sensing deployment to detect the low pressure region and a similarly dense deployment of actuators to manage the turbulent flow. With this concept, only the actuators in the vicinity of a separation layer are activated, minimizing power consumption and also the induced drag.

Para lá dos jornalistas: influencer relations, uma nova era de Media Relations

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Gestão Estratégica das Relações Públicas.

As Guerras Mundiais e as mutações na teoria social da comunicação e dos media

Se a guerra é a continuação da política por outros meios, então certamente que nela a comunicação, em sentido lato, esteve sempre presente e desempenhou um papel chave. As guerras não implicam apenas a violência, mas também a persuasão, a contrainformação, o convencimento e o combate ideológico. Nas guerras modernas, os media têm sido um elemento fundamental para mobilizar nações moldadas por dinâmicas de desenraizamento e desterritorialização com vista a um esforço conjunto de apoio popular à ação bélica do Estado. Este artigo incide nas transformações que a própria teoria e investigação em comunicação e media sofreram no período entre as duas Guerras Mundiais do século XX. Trata-se de um contexto histórico decisivo para compreender como a institucionalização do campo da comunicação num país central como os EUA ocorreu em condições sociais e políticas que contribuíram para o seu perfil epistemológico, posições teóricas e para a configuração do poder no próprio sistema científico universitário, cujas repercussões continuam a fazer-se sentir de diversas e complexas formas.

Engineering PROFIBUS networks with heterogeneous transmission media

A significant number of process control and factory automation systems use PROFIBUS as the underlying fieldbus communication network. The process of properly setting up a PROFIBUS network is not a straightforward task. In fact, a number of network parameters must be set for guaranteeing the required levels of timeliness and dependability. Engineering PROFIBUS networks is even more subtle when the network includes various physical segments exhibiting heterogeneous specifications, such as bus speed or frame formats, just to mention a few. In this paper we provide underlying theory and a methodology to guarantee the proper operation of such type of heterogeneous PROFIBUS networks. We additionally show how the methodology can be applied to the practical case of PROFIBUS networks containing simultaneously DP (Decentralised Periphery) and PA (Process Automation) segments, two of the most used commercial-off-the-shelf (COTS) PROFIBUS solutions. The importance of the findings is however not limited to this case. The proposed methodology can be generalised to cover other heterogeneous infrastructures. Hybrid wired/wireless solutions are just an example for which an enormous eagerness exists.