Estabelecendo conexões entre números racionais: O caso da percentagem

Esta comunicação decorre de um trabalho de investigação, centrado uma experiência de ensino no tema Números Racionais, com uma turma do 5.º ano de escolaridade, em que se procurou criar um contexto favorável ao estabelecimento de conexões entre as várias representações dos racionais, através de problemas e tarefas de natureza exploratória e do uso de modelos, principalmente a barra numérica. Na presente comunicação procuramos analisar que conhecimentos sobre percentagem os alunos de um grupo possuíam inicialmente e como usam, posteriormente, no decurso da experiência de ensino, a percentagem para comparar números racionais numa situação de partilha equitativa, evidenciando já alguma flexibilidade para considerarem a representação que lhes é mais conveniente.FCT - Fundação para a Ciência e Tecnologi

Macrophages control tissue homeostasis via Ferritin heavy chain

Due to its inherent capacity to catalyze reduction-oxidation reactions, iron is at the center stage of vital biological functions essential to most living organisms. Paradoxically, these same inherent characteristics are also responsible for the deleterious effects of iron. In the intracellular environment, iron is oxidized to its inert biological form by the ferroxidase activity of Ferritin Heavy Chain (FTH). In this Thesis we used a genetic loss of function approach in mice to demonstrate that FTH is essential to control the deleterious effects of iron and as such to maintain homeostasis in vivo. Namely we found that global deletion of the Fth allele is lethal in adult mice, an outcome prevented by the expression of FTH in macrophages. To investigate further the mechanisms by which FTH in macrophages contributes to maintain homeostasis we generated and characterized a genetically modified mouse strain in which FTH was tagged with a small V5 epitope. We found that contrary to what would be expected FTH is not secreted from macrophages to exert its protective effect. We conclude that FTH expression in macrophages acts in a cell autonomous manner to support homeostasis

ENVIE Co-ordination action on indoor air quality and health effects; WP3 Final report – Characterisation of spaces and source

Human exposure to environmental pollutants occurs via various pathways. For many pollutants, especially the volatile ones, air exposure is the dominant pathway. Exposure via air occurs both outdoors and indoors, with diverse types of indoor spaces playing a role, e.g., home, workplace, and passenger cabins of means of transportation. In average people spend over 90% of their time indoors, that percentage being particularly high for some specific groups as new-born, elderly, disabled or sick people. The global exposure to air contaminants is therefore drastically determined by indoor conditions. It is now well established that indoor air pollution contributes significantly to the global burden of disease of the population. For a majority of indoor air contaminants, particularly in the presence of common indoor sources, however, indoor concentrations usually exceed outdoor concentrations, for some pollutants even with an indoor/outdoor ratio of 10 or 20. Emissions are identified, accordingly to the EnVIE approach and grouped into four categories: building materials and related sources, including dampness and moulds; ventilation, natural and mechanical, including, or not, heating, cooling and humidification/ dehumidification; consumer products, furnishing, cleaning and household products; and occupant activities. Emission of chemical substances from construction materials and products in buildings to the indoor air have been reported and reviewed for a wide range of substances, including those formed during secondary reactions, causing complaints of irritation and odour. During the last two decades there has been increasing advances in construction technology that have caused a much greater use of synthetic building materials. Whilst these improvements have led to more comfortable buildings, they also provide indoor environments with contaminants in higher concentrations than are found outside. Wood and cork are now frequently used as a building product for floor coverings, because the material is often regarded as “natural” and “healthy”. However, industrial products, even based on natural raw materials, may contain a number of artificial ingredients and the chemical emissions will strongly depend on the type of additives and the manufacturing process. Modern interior paints are usually based on a polymeric binder. In order to fulfil requirements on e.g., durability, paint contains various functional chemicals. Water-borne paints usually also contains small amounts of approved biocides. Polymeric binders with a very low content of residual monomers have been developed for paint. Besides the release of substances to the indoor air due to primary emission, damp building materials may give rise to volatile substances formed during secondary reactions. Semi-volatile organic compounds (SVOCs) are now receiving much more attention than heretofore. The HVAC (Heating, Ventilation and Air Conditioning) systems as providers, among others, of services of cleaning and dilution of pollutants in the indoor air are also recognized as potential pollution sources. Several studies have shown that the prevalence of SBS symptoms is often higher in air conditioned buildings than in buildings with natural ventilation. 8 The outdoor air introduced indoors through either ventilation systems or natural means is also an important and not always controllable source for the intake of some outdoor pollutants. Outdoor air used for ventilation may also be source of pollution containing particulate matter, particulates of biological origin (microorganisms, pollen, etc.) and various gases like NOx and O building structures which is a driving force for the airflows which will transport to indoors water vapour and gaseous or particulate contaminants. Volatile organic compounds are emitted from a wide variety of household and consumer products with emission rates that are strongly dependent on the type of application and are distributed over several orders of magnitude. A number of product classes are identified and information on ingredients and available data on emissions from individual products are presented. Human activities and the associated use of products encompass a wide range of indoor sources involving release of inorganic gases, particles and organic compounds as a consequence of the activity. For some releases such as with air fresheners the release is a necessary part of the activity to achieve the intended effect whereas for others, such as the release of combustion fumes from a gas appliance, the purpose of the action (in this case generation of heat) is different from the emission. Combustion processes are an important source of a range of air pollutants as carbon monoxide, nitrogen dioxide, sulphur dioxide, particulates and associated inorganic and organic chemicals, organic vapours e.g. formaldehyde, acetaldehyde, and benzene. Sources of these are present in both ambient and indoor environments. The concentrations present in the ambient air provide a baseline for the level of pollutant found indoors as this air enters indoors by processes of infiltration and ventilation. However, the concentration indoors will be modified by processes of sorption to surfaces and chemical reaction depending on the chemical and physical properties of the pollutant and internal surfaces. People themselves are a source of emissions of chemicals and gases, notably CO range of organic compounds that are referred to as body odours. The removal of such body odours is a prime objective of ventilation in order to achieve a satisfactory indoor environment. WP3 aims at to characterize spaces and sources in order to understand where and how to act to guarantee good IAQ. From the two strategies for good IAQ, source control and ventilation, the precautionary principle suggests that first priority shall be given to source control, avoiding, mitigating or simply managing sources of emissions. An overview of all policies on IAQ or related to IAQ, existing or in preparation, directly related to indoor air sources, but also covering outdoor air and industrial emissions, which could affect indirectly IAQ is made. Considering the presented it could be concluded that IAQ is yet poorly regulated at EU level, and in view of that some recommendations are made. The recommendations on policies have taken into account the existing related to IAQ policies such as new EU policies on chemicals (REACH; 2006/121/EC), consumer products (GPSD; 2001/95/EC), construction products (CPD; 89/106/EC) and energy performance of buildings (EPBD; 2002/91/EC) all refer to IAQ issues - suggesting that they could, and probably should, contribute to IAQ policy development and advocate an integrative and comprehensive policy approach centred

Feature-based underwater localization using an imaging sonar

The ability of an AUV to locate itself in an environment as well as to detect relevant environmental features is of key importance for navigation success. Sonars are one the most common sensing devices for underwater localization and mapping, being used to detect and identify underwater structural features. This study explores the processing and analysis of acoustic images, through the data acquired by a mechanical scanning imaging sonar, in order to extract relevant environmental features that enable location estimation. For this purpose, the performances of different state-of-the art feature extraction algorithms were evaluated. Furthermore, an improvement to the feature matching step is proposed, in order to adapt this procedure to the characteristics of acoustic images. The extracted features are then used to feed a location estimator composed of a Simultaneous Localization and Mapping algorithm implementing an Extended Kalman Filter. Several tests were performed in a structured environment and the results of the feature extraction process and localization are presented

ACQUISITION AS A GENERATOR STRATEGY FROM COMPETITIVE ADVANTAGES IN THE BRAZILIAN MARKET OF FUELS DISTRIBUITION

The subject from this work is about acquisitions as organizational strategies and it is guided by the general objective on identifying if the acquisition of Texaco by Ultra Group, in Brazil, could generate competitive advantages. Thus, the main aim is to characterize, specifically, the fuel distribution sector in Brazil, presenting characteristics, strategies, classification of resources and the competitive advantage’s identification in the buying process of Texaco by Ultra Group. The methodology used for this research is a case study of qualitative nature. Data collection has been performed through literature review, documentary analysis and semi-structured interviews. In the analysis of collected data, specific objectives have been met. It was clear, therefore, the presence of features such as scale earnings, brand exposure, better management practices, synergies, tangible and intangible assets and market growth. So, those resources are classified according to the competitive implications. Then, it might be concluded that Texaco´s acquisition could bring competitive advantages for Ultra / Ipiranga Group. Respondents believe the sector is growing and businesses tend to grow despite the world crisis. They also confirmed that, in a highly competitive market, strategic alliances and market growing are factors that may ensure success to each company

Apneia do sono e perda auditiva em Indivíduos do sexo masculino

O Síndrome da Apneia Obstrutiva do Sono (SAOS) é uma perturbação respiratória relacionada com o sono, que consiste na obstrução do fluxo respiratório durante o sono por um período igual ou superior a dez segundos e mais do que cinco vezes por hora. Um dos efeitos mais claros desencadeados por este síndrome é a sensação de cansaço pela incapacidade de completar um ciclo de sono. O ciclo do sono é composto por cinco fases que podem durar de setenta a cento e vinte minutos. Durante este período ocorrem vários ciclos, podendo em cada noite realizar-se de quatro a seis ciclos.info:eu-repo/semantics/publishedVersio

Relationships between grandparents and their teenage grandchildren: an integrative review

O objetivo do estudo foi analisar a relação entre avós e seus netos adolescentes, e descrever suas diferentes representações no cotidiano de seus netos por meio de revisão integrativa. Realizou-se a busca de artigos e resumos publicados no período de janeiro 2002 a junho de 2012, nas bases de dados LILACS e MEDLINE, por meio dos seguintes descritores: avós, netos adolescentes, relações entre avós e netos. Seguindo as estratégias definidas para o estudo, a busca resultou em seis artigos na íntegra. Foram incluídos dois artigos da base de dados LILACS e quatro da MEDLINE. Concluiu-se que as relações entre avós e netos adolescentes se diferenciaram de acordo com a proximidade entre os sujeitos, sendo esta derivada de diversos fatores, como corresidência, trabalho e estado civil dos netos, opções sexuais GLBT, origem e doenças crônicas dos avós. Pesquisas futuras que estudem essa temática são importantes para contribuir com um melhor entendimento da relação entre avós e seus netos na perspectiva de ambos os sujeitos.This study aimed to analyze the relationship between grandparents and their teenage grandchildren, and describe different representations in everyday of their grandchildren through an integrative review. A search for articles and abstracts published from January 2002 to June 2012, was conducted in MEDLINE and LILACS databases using the following descriptors: grandparents, grandchildren teenagers, relationships between grandparents and grandchildren. Following the strategies defined for the study, the search resulted in six full articles. Two articles from LILACS and four from MEDLINE were included. The conclusion was that the relationship between grandparents and teenage grandchildren differed according to the proximity of the subject, which is derived from several factors such as co-residence, work and marital status of the grandchildren, GLBT sexual choices, and chronic source of grandparents. Future research work assessing this issue are important to contribute to a better understanding of the relationship between grandparents and grandchildren from the perspective of both subjects