RESUMO A intenção de abandonar a profissão é um importante preditor do abandono profissional, com repercussões negativas para a qualidade do ensino, desempenho escolar e comunidade em geral. O objetivo do estudo foi identificar o poder preditivo dos estressores ocupacionais para a tendência ao abandono profissional em professores. Participaram do estudo 376 professores de escolas municipais de uma cidade da região metropolitana de Porto Alegre. Como instrumentos de avaliação foram utilizados um questionário de dados sociodemográficos e laborais, uma escala de avaliação de tendência ao abandono e um questionário de estressores ocupacionais docentes. Os resultados, obtidos por meio da análise de regressão linear, apontaram como preditores do abandono profissional os estressores multiplicidade de papéis a desempenhar, conciliar trabalho e lazer e a relação com alunos. O estudo sugere possíveis intervenções como forma preventiva, assim como indica possibilidades de novos estudos.

Characterisations of ancient sheep breeds and wool types and theories about wool fibre processing are integral parts of textile archaeology. The studies build on statistical calculations of measurements of wool fibre diameters and reveal characteristics of the yarns that are attributed to the available raw wool and to the production methods of the time. Different microscope types have been used for data collection. Presently digital images from either scanning electron microscopy (SEM) or transmitted light microscopy (TLM) are the preferred methods. The advantage of SEM is the good depth of field at high magnification, while TLM is simpler to use and more readily available. Several classification systems have been developed to facilitate the interpretation of the results. In this article, the comparability of the results from these two methods and from the use of different magnifications in general is examined based on the analyses of a large number of the Danish prehistoric textiles. The results do not indicate superiority of one microscope type in favour of another. Rather, they reveal differences in the calculations that can be ascribed to the diversity of the fibres in the individual yarns as well as to the methodology and the magnification level.

Many ancient Chinese bronze mirrors have survived with a patina that leaves the delicate surface decorations intact. The microstructure of these mirrors is two-phase: Cu-rich α and Sn-rich δ. Although the mirrors have been labeled ‘corrosion-resistant’, the smooth surface includes a corroded layer up to 100 µm thick. In this ‘altered’ layer, there is selective attack of the α phase; the α-phase regions are replaced by tin oxide with the δ phase remaining metallic. Here, electrochemical polarization has been used to drive the dealloying process in modern, cast bronze duplicating the microstructure on ancient bronzes. Timed experiments were performed to investigate the growth of the ‘altered’ region on the model samples. The altered layer forms quickly but the rate of growth slows over time. Theoretical calculations show that dissolution of copper from the α phase leaves a large volume for the tin oxide corrosion product permitting retention of the smooth surface.

This paper describes a cleaning method for removing ingrained carbonaceous dirt from lime-based wall paintings by utilizing hydrogels in combination with aqueous cleaning liquids. Nanorestore Gel® Peggy 6 has a number of advantages over traditional cleaning methods, and it is capable of holding large amounts of liquid, but it limits liquid penetration into the substrate. Cleaning action occurs only at the interface, without affecting the surrounding area or leaving residues. Furthermore, its viscosity makes it an ideal tool for treating irregular, vaulted surfaces. Laboratory experiments conducted on limewashed model tiles were decisive in the design of in situ experiments on fifteenth-century wall paintings. The cleaning efficiency of each method was assessed and quantified using colorimetry, 2-D FTIR mapping and image analysis using Cultural Heritage ImageJ. SEM-EDX was used for seeking residues. Results of both the model and in situ cleaning tests show a significant reduction of ingrained dirt when comparing Nanorestore Gel® Peggy 6 to traditional methods. Best visual results were obtained when cleaning with hydrogel loaded with 5% triammonium citrate was following by swabbing with a wet sponge. However, using water alone with the gel yielded almost as good a result in situ, making cleaning possible without any risk of residues.

In this article we present the fragments of a crucible and a possible tuyère that provide evidence of early copper metallurgy in Scandinavia at least 1500 years earlier than previously thought. The technical ceramics were found in a cultural layer containing Early Neolithic Funnel Beaker pottery dating to around 3800–3500bcbeneath a long barrow dating to 3300–3100bc. The presence of a copper alloy in the crucible is confirmed by three independent X-ray fluorescence analyses using both a hand-held and a stationary instrument, SEM-EDS analysis of a cross-section, as well as a Bruker Tornado μ-X-Ray-fluorescence scanner (μ-XRF). The transmission of metallurgy to southern Scandinavia coincided with the introduction of long barrows, causewayed enclosures, two-aisled houses, and certain types of artefacts. Thus, metallurgy seems to be part of the new networks that enabled the establishment of a fully Neolithic society.