431 research outputs found
No future in archaeological heritage management?
Although the future is mentioned frequently in overarching aims and visions, and it is a major drive in the daily work of archaeological heritage managers and indeed heritage professionals more generally, it remains unclear precisely how an overall commitment to the future can best inform specific heritage practices. It seems that most archaeologists and other heritage professionals cannot easily express how they conceive of the future they work for, and how their work will impact on that future. The future tends to remain implicit in daily practice which operates in a continuing, rolling present. The authors argue that this needs to change because present-day heritage management may be much less beneficial for the future than we commonly expect
Simulations of Weighted Tree Automata
Simulations of weighted tree automata (wta) are considered. It is shown how
such simulations can be decomposed into simpler functional and dual functional
simulations also called forward and backward simulations. In addition, it is
shown in several cases (fields, commutative rings, Noetherian semirings,
semiring of natural numbers) that all equivalent wta M and N can be joined by a
finite chain of simulations. More precisely, in all mentioned cases there
exists a single wta that simulates both M and N. Those results immediately
yield decidability of equivalence provided that the semiring is finitely (and
effectively) presented.Comment: 17 pages, 2 figure
Guidelines for the establishment of microbiological criteria for foods
O Grupo de Trabalho OcorrĂȘncia MicrobiolĂłgica na Cadeia Alimentar
(GTOMCA) do Programa PortFIR considerou de grande importĂąncia o desenvolvimento
de um documento que compilasse uma seleção de legislação
e de informaçÔes relativas a Critérios Microbiológicos (CM), visando apoiar
e facilitar, aos operadores e entidades do setor alimentar, a sua aplicação
na validação do processo de produção, na segurança e/ou higiene dos géneros
alimentĂcios, na adesĂŁo a boas prĂĄticas de fabrico dos mesmos, e/ou,
ainda, na manutenção da sua qualidade durante o seu tempo de vida Ăștil.
Deste modo, o GTOMCA desenvolveu o Guia para o estabelecimento de
critĂ©rios microbiolĂłgicos em gĂ©neros alimentĂcios, que foi publicado em
abril de 2017, contemplando a identificação, caraterĂsticas e propĂłsito dos
CM, os fatores a considerar para a sua definição, nomeadamente: a categoria
do alimento, o microrganismo e/ou as suas toxinas, os metabolitos e
a virulĂȘncia, os valores limite, o plano de amostragem, o tipo de utilização
e consumo assim como o método de anålise laboratorial, o ponto da cadeia
alimentar onde se aplica, as medidas a tomar no caso de resultados nĂŁo satisfatĂłrios
e a necessidade de revisão e atualização dos CM.The Working Group on Microbiological Occurrence on the Food Chain
(GTOMCA) of Por tFIR Program considered unanimously, as an important
need, the existence of a document with a selection and compilation
of existing legislation and information concerning microbiological
criteria (CM) as a tool to suppor t and facilitate its application by operators
and entities in the food sector to validate the acceptability of
the production process or the food safety or hygiene, the obser vance
to good manufacturing practices or the maintenance of the food
quality during its lifetime. So, GTOMCA developed a Guide for the establishment
of microbiological criteria in foodstuf fs, which was published
in April 2017, regarding the identification, characteristics and
purpose of microbiological criteria, the factors to consider for its definition,
identification, characteristics and purpose of CM and, as impor
tant factors to consider the food categor y, the micro-organism
and its metabolites, toxins and virulence factors, the limit values, the
sampling plan, the type of food consumption as well as the analy tical
method for testing the food, the point of the food chain where it is applied,
the measures to be taken in the event of unsatisfactor y results
and the need to review and update of the CM.info:eu-repo/semantics/publishedVersio
Is the high 15N natural abundance of trees in N-loaded forests caused by an internal ecosystem N isotope redistribution or a change in the ecosystem N isotope mass balance?
Foliar ÎŽ15N values characterize soil N cycling and reflect nitrate or ammonium preference of plants along a temperate grassland gradient
The natural abundance of stable 15N isotopes in soils and plants is potentially a simple tool to assess ecosystem N dynamics. Several open questions remain, however, in particular regarding the mechanisms driving the variability of foliar ÎŽ15N values of non-N2 fixing plants within and across ecosystems. The goal of the work presented here was therefore to: (1) characterize the relationship between soil net mineralization and variability of foliar ÎÎŽ15N (ÎŽ15Nleaf â Ύ15Nsoil) values from 20 different plant species within and across 18 grassland sites; (2) to determine in situ if a plantâs preference for NO3â or NH4+ uptake explains variability in foliar ÎÎŽ15N among different plant species within an ecosystem; and (3) test if variability in foliar ÎÎŽ15N among species or functional group is consistent across 18 grassland sites. ÎÎŽ15N values of the 20 different plant species were positively related to soil net mineralization rates across the 18 sites. We found that within a site, foliar ÎÎŽ15N values increased with the speciesâ NO3â to NH4+ uptake ratios. Interestingly, the slope of this relationship differed in direction from previously published studies. Finally, the variability in foliar ÎÎŽ15N values among species was not consistent across 18 grassland sites but was significantly influenced by N mineralization rates and the abundance of a particular species in a site. Our findings improve the mechanistic understanding of the commonly observed variability in foliar ÎÎŽ15N among different plant species. In particular we were able to show that within a site, foliar ÎŽ15N values nicely reflect a plantâs N source but that the direction of the relationship between NO3â to NH4+ uptake and foliar ÎÎŽ15N values is not universal. Using a large set of data, our study highlights that foliar ÎÎŽ15N values are valuable tools to assess plant N uptake patterns and to characterize the soil N cycle across different ecosystems
Heritage Futures - Comparative Approaches to Natural and Cultural Heritage Practices
This is the final version. Available on open access from UCL Press via the DOI in this recordWe present the book as a co-authored monograph because we acknowledge the collective contributions to the arguments developed within it, and the collaborative nature of the work. This has in itself been an experiment in finding a format in which diverse voices and views could productively speak to one another, while also acknowledging and foregrounding the diversity and range of different views, academic traditions and writing styles of contributors. As principal investigator, Harrison acted as the lead and coordinating author of the book, taking overall responsibilities for its editing and production. The co-investigators (DeSilvey, Holtorf, Macdonald) shared with Harrison editorial responsibilities for the individual thematic parts they each led, and for shaping the intellectual agenda of the book as a whole. However, we also felt it important to indicate the main authors of individual chapters within the book, to make clear specific contributions to the text and its arguments, and to highlight which named individuals were responsible for the empirical work that underpins them.
Preservation of natural and cultural heritage is often said to be something that is done for the future, or on behalf of future generations, but the precise relationship of such practices to the future is rarely reflected upon. Heritage Futures draws on research undertaken over four years by an interdisciplinary, international team of 16 researchers and more than 25 partner organisations to explore the role of heritage and heritage-like practices in building future worlds.
Engaging broad themes such as diversity, transformation, profusion and uncertainty, Heritage Futures aims to understand how a range of conservation and preservation practices across a number of countries assemble and resource different kinds of futures, and the possibilities that emerge from such collaborative research for alternative approaches to heritage in the Anthropocene. Case studies include the cryopreservation of endangered DNA in frozen zoos, nuclear waste management, seed biobanking, landscape rewilding, social history collecting, space messaging, endangered language documentation, built and natural heritage management, domestic keeping and discarding practices, and world heritage site management.Arts and Humanities Research Council (AHRC
Behavioral Modernity and the Cultural Transmission of Structured Information: The Semantic Axelrod Model
Cultural transmission models are coming to the fore in explaining increases
in the Paleolithic toolkit richness and diversity. During the later
Paleolithic, technologies increase not only in terms of diversity but also in
their complexity and interdependence. As Mesoudi and O'Brien (2008) have shown,
selection broadly favors social learning of information that is hierarchical
and structured, and multiple studies have demonstrated that teaching within a
social learning environment can increase fitness. We believe that teaching also
provides the scaffolding for transmission of more complex cultural traits.
Here, we introduce an extension of the Axelrod (1997} model of cultural
differentiation in which traits have prerequisite relationships, and where
social learning is dependent upon the ordering of those prerequisites. We
examine the resulting structure of cultural repertoires as learning
environments range from largely unstructured imitation, to structured teaching
of necessary prerequisites, and we find that in combination with individual
learning and innovation, high probabilities of teaching prerequisites leads to
richer cultural repertoires. Our results point to ways in which we can build
more comprehensive explanations of the archaeological record of the Paleolithic
as well as other cases of technological change.Comment: 24 pages, 7 figures. Submitted to "Learning Strategies and Cultural
Evolution during the Paleolithic", edited by Kenichi Aoki and Alex Mesoudi,
and presented at the 79th Annual Meeting of the Society for American
Archaeology, Austin TX. Revised 5/14/1
Biogenic Volatile Organic Compound and Respiratory CO2 Emissions after 13C-Labeling: Online Tracing of C Translocation Dynamics in Poplar Plants
Globally plants are the primary sink of atmospheric CO(2), but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important.We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either (13)CO(2) to leaves or (13)C-glucose to shoots via xylem uptake. The translocation of (13)CO(2) from the source to other plant parts could be traced by (13)C-labeled isoprene and respiratory (13)CO(2) emission.In intact plants, assimilated (13)CO(2) was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3±2.5 cm h(-1). (13)C label was stored in the roots and partially reallocated to the plants' apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76-78%) from recently fixed CO(2), to a minor extent from xylem-transported sugars (7-11%) and from photosynthetic intermediates with slower turnover rates (8-11%).We quantified the plants' C loss as respiratory CO(2) and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux
Boreal forest soil carbon fluxes one year after a wildfire: Effects of burn severity and management
The extreme 2018 hot drought that affected central and northern Europe led to the worst wildfire season in Sweden in over a century. The Ljusdal fire complex, the largest area burnt that year (8995 ha), offered a rare opportunity to quantify the combined impacts of wildfire and post-fire management on Scandinavian boreal forests. We present chamber measurements of soil CO2 and CH4 fluxes, soil microclimate and nutrient content from five Pinus sylvestris sites for the first growing season after the fire. We analysed the effects of three factors on forest soils: burn severity, salvage-logging and stand age. None of these caused significant differences in soil CH4 uptake. Soil respiration, however, declined significantly after a high-severity fire (complete tree mortality) but not after a low-severity fire (no tree mortality), despite substantial losses of the organic layer. Tree root respiration is thus key in determining post-fire soil CO2 emissions and may benefit, along with heterotrophic respiration, from the nutrient pulse after a low-severity fire. Salvage-logging after a high-severity fire had no significant effects on soil carbon fluxes, microclimate or nutrient content compared with leaving the dead trees standing, although differences are expected to emerge in the long term. In contrast, the impact of stand age was substantial: a young burnt stand experienced more extreme microclimate, lower soil nutrient supply and significantly lower soil respiration than a mature burnt stand, due to a thinner organic layer and the decade-long effects of a previous clear-cut and soil scarification. Disturbance history and burn severity are, therefore, important factors for predicting changes in the boreal forest carbon sink after wildfires. The presented short-term effects and ongoing monitoring will provide essential information for sustainable management strategies in response to the increasing risk of wildfire
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Beyond the martial façade: gender, heritage and medieval castles
Gendered interpretations are rare both within castle-studies and heritage discourses on medieval castles. Yet, castles hold potential to inform multi-vocal accounts of the medieval past and to inspire meaningful heritage interpretations to achieve greater societal impact. This article explores the role that gender currently plays in interpretations of medieval castles in Britain, supported by three case-studies written by heritage professionals. The enduring narrative of militarism at medieval castles sites is discussed, together with issues of authenticity in relation to the historical record, which is in itself biased and inherently gendered. Outcomes from a collaborative workshop highlight the need to address interpretative issues where gender is considered to equate to âmaking women visibleâ. Finally, we pose the question: What makes a âgood gendered interpretationâ at a public heritage site
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