Relationship between nano-architectured Ti1−xCux thin film and electrical resistivity for resistance temperature detectors

Ti1−xCux thin films were produced by the glancing angle deposition technique (GLAD) for resistance temperature measurements. The deposition angle was fixed at α = 0° to growth columnar structures and α = 45° to growth zigzag structures. The Ti-to-Cu atomic concentration was tuned from 0 to 100 at.% of Cu in order to optimize the temperature coefficient of resistance (TCR) value. Increasing the amount of Cu in the Ti1−xCux thin films, the electrical conductivity was gradually changed from 4.35 to 7.87 × 105 Ω−1 m−1. After thermal “stabilization,” the zigzag structures of Ti1−xCux films induce strong variation of the thermosensitive response of the materials and exhibited a reversible resistivity versus temperature between 35 and 200 °C. The results reveal that the microstructure has an evident influence on the overall response of the films, leading to values of TCR of 8.73 × 10−3 °C−1 for pure copper films and of 4.38 × 10−3 °C−1 for a films of composition Ti0.49Cu0.51. These values are very close to the ones reported for the bulk platinum (3.93 × 10−3 °C−1), which is known to be one of the best material available for these kind of temperature-related applications. The non-existence of hysteresis in the electrical response of consecutive heating and cooling steps indicates the viability of these nanostructured zigzag materials to be used as thermosensitive sensors.Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and Project PTDC/EEI-SII/5582/2014. A. Ferreira and C. Lopes thanks the FCT for Grant SFRH/BPD/102402/2014 and SFRH/BD/103373/2014. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Programinfo:eu-repo/semantics/publishedVersio

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Regional variability in peatland burning at mid-to high-latitudes during the Holocene

Northern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal records from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (∼9–6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires

Palaeoenvironmental conditions and human activity in the vicinity of the Grodzisko fortified settlement (central Europe, Poland) from the late-Neolithic to the Roman period

We present results from a palaeoecological analysis conducted on deposits accumulated in an oxbow lake of the Prosna River (Poland), next to the Grodzisko fortified settlement. Palaeobotanical and geochemical analyses—supported by radiocarbon dating—were performed to (i) reconstruct palaeoenvironmental conditions of the oxbow lake and its surrounding area; (ii) determine the beginning of the human activity in the fortified settlement vicinity; and (iii) assess the impact of human pressure on the environment. The Grodzisko fortified settlement was originally located on a river island, encircled by a wetland, improving its defensive value. Increases in the water level (1800–1300 BC and 700–200 BC) created a small lake/moat around the fortified settlement. Indicators for human activity from pollen records suggest the presence of human populations from the late Neolithic, ca. 2800 BC, with a clear intensification ca. 1700 BC. From ca. 1600 BC, a decrease in some decidous trees suggests forest clearance. Low levels of human activity indicator pollen ca. 2000 BC suggest a reduction of human pressure (possible depopulation). The regular presence of macrocharcoal pieces and an increase in human activity indicator pollen from ca. 1300 to 200 BC provide evidence for renewed human habitation around the sampling site

Technology-enhanced Professional Learning

Societal and technological changes are transforming the ways people work and learn. As work roles evolve, learning for work becomes continual and personalised. These transformations evidenced in work and learning practices are partly governed by advances in technology. Consideration of work practices, professional learning processes and technologies mediating work and learning within a single domain of "Technology-enhanced Professional Learning" enables analysis of the dialectical relationship between technology and practice. This chapter begins by presenting a single framework that integrates perspectives across the domains of work practices, learning processes and digital technologies. Key trends are outlined from the literature within each domain. Using a framework for TEPL as an analytical lens, emerging work and technology practices and their implications for professional learning both in and for work are examined. Finally, the chapter outlines the implications of these developments for work and learning

Steering Epitaxial Growth

Attractive dispersion forces, active between incident atoms and the substrate, cause preferential arrival of atoms on protruding parts on growing film surfaces. This phenomenon, which we refer to as “steering”, can give rise to significant flux redistribution. The lack of incident flux homogeneity, disregarded so far in growth studies, contributes to enhanced roughness of the growth front. This principal disadvantage can be turned around. In a quite narrow window of polar angles of incidence, it becomes possible to fabricate one-dimensional arrays of ripples oriented perpendicular to the plane of incidence. Several aspects of the mechanism, as well as an application of one-dimensional magnetic aggregates, are discussed