76,520 research outputs found

    Actively decaying or just poorly preserved? Can we tell when plant and invertebrate remains in urban archaeological deposits decayed?

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    We have recendy argued that poorly preserved delicate macrofossil remains of plants and invertebrates in near-surface deposits in York are in active decay, rather than being preserved in stasis, part-way down the decay trajectory. Observations of both archaeological and modern deposits suggest empirically that remains either survive for a long period (if conditions are conducive) or decay rapidly (if they are not). The hypothesis that very gradual decay has led to large numbers of deposits containing remains in a similar state appears illogical. It is more likely that, where poorly preserved biological remains are found, they either decayed in the past and then were stabilised when ground conditions became anoxic, or are currently in decay. Long-term patterns of decay cannot easily be investigated experimentally, but arguments concerning patterns and rates of decay can be. Apart from the question of in-ground preservation, understanding patterns of decay will allow us to address a range of taphonomic problems fundamental to drawing archaeological information from these remains

    Evidence for tanning from plant and insect remains

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    [FIRST PARAGRAPH] It is suggested elsewhere (Hall and Kenward forthcoming) that a bioarchaeological 'indicator group' (sensa Kenward and Hall 1997) for tanning may be recognisable. The material giving rise to this hypothesis was discovered during assessment of samples from Anglo-Scandinavian and early post- Conquest riverside deposits at Layerthorpe Bridge, York (Carrott et al. 1997). Here, large quantities of bark fragments (and the sclereids -small clumps of lignified cells characteristic of certain trees, notably oak- left when bark decays) were recorded in many samples. These gave the suspicion that the bark was being employed for some purpose, since there was usually very little wood present with it. Much the most likely process to have required bark in bulk is tanning (taken here to represent the steeping of hides in pits or vats with tree bark). Support for this came from a somewhat surprising direction. The beetle Trox scaber was unusually abundant (it was found in 30 of the samples, at a frequency of 3-6 per sample when present; five samples contained 'several' individuals and one 'many’, on the semi-quantitative scale used for recording). This contrasts with the evidence from Anglo-Scandinavian Coppergate, where it was present in a large proportion (242) of the samples but was never abundant. There were only eight cases where three or four individuals were noted, the rest being ones or twos, and the mean number of individuals per sample where the beetle was present was 1.2 (AY 14/7; Kenward, unpublished database). Thus T. scaber was significantly more abundant at the Layerthorpe Bridge site than at Coppergate

    Setting people in their environment: plant and animal remains from Anglo-Scandinavian York

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    INTRODUCTION: For the past millennium, the inhabitants of the centre of York have, whether hey knew it or not, been living on top of a compost heap in which are preserved all kinds of remains of Anglo-Scandinavian and early post-conquest life. The preservation of this mass of organic matter has come about because, for reasons which are not fully understood, the deposits show anoxic waterlogging - in other words they have remained moist, and decay has been inhibited by lack of free oxygen. Later citizens must often have encountered these 'peaty' deposits and wondered about some of the more recognisable biological remains, as well as the numerous artefacts, surviving in them. However, it was not until the early 20th century that the value of all this material in investigating the past started to be appreciated

    The bioarchaeology of Anglo-Saxon Yorkshire: present and future perspectives

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    The Anglo-Saxon period in Yorkshire - in terms of our knowledge of those questions which bioarchaeological studies are conventionally used to address - remains very much an unknown quantity, We can hardly claim even to know whether these questions are indeed appropriate in the Anglo-Saxon period. To some extent this reflects the nature of the Anglo-Saxon deposits so far encountered, in which preservation of the less durable organic remains has been very limited. The nature of Anglo-Saxon occupation, with a bias towards rural settlements of a kind whicb have generally left only faint traces in the ground, means that there are no deeply stratified richly organic deposits of the kind revealed in some Roman and Viking Age phases in major urban centres, of which only York is weIl known in the region. The Anglo-Saxon period thus presents exceptional challenges to the environmental archaeologist, and ones which closely parallel those for the Iron Age. It is a period for which the kind of assemblages traditionally provided by bioarchaeologica1 studies are most urgently needed, to define environment and land use, resource exploitation, living conditions, trade and exchange, as well as aspects of craft-working and industrial activities. In addition, the period in Yorkshire presents special problems concerning the status of individual rural or ecclesiastical settlements, particularly the nature of York as a possible wic. For the purposes of this paper (and in view of the complexities of the archaeology of the 5th to 11th centuries), we have elected to discuss only such biological material as .falls after the end of the Roman period (as generally accepted) and before the first significant waves of Scandinavian invasion in the mid 9th century

    Reply to Comment by Galapon on 'Almost-periodic time observables for bound quantum systems'

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    In a recent paper [1] (also at http://lanl.arxiv.org/abs/0803.3721), I made several critical remarks on a 'Hermitian time operator' proposed by Galapon [2] (also at http://lanl.arxiv.org/abs/quant-ph/0111061). Galapon has correctly pointed out that remarks pertaining to 'denseness' of the commutator domain are wrong [3]. However, the other remarks still apply, and it is further noted that a given quantum system can be a member of this domain only at a set of times of total measure zero.Comment: 3 page

    Heart of Darkness: Modeling Public-Private Funding Interactions Inside the R&D Black Box

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    This paper is a first step toward closing the analytical gap in the extensive literature on the results of interactions between public and private R&D expenditures, and their joint effects on the economy. Earlier studies frequently report contradictory estimates of the response of company financed R&D to changes in the level and nature of public R&D expenditure. A major cause of "inconsistencies" in the empirical literature is the failure to recognize key differences among the various policy "experiments" being considered depending upon the economy in which they are embedded, and the type of public sector R&D spending that is contemplated. Using a simple, stylized structural model, we identify the main channels of impact of public R&D and characterize the various effects, distinguishing between short-run and long-run impacts that would show up in simple regression analyses of nominal public and private R&D expenditure variables. We offer interpretations that shed light on recent cross-section and panel data findings at both high (i.e. national) and low (specific technology area) levels of aggregation.

    Heart of Darkness: Modeling Public-Private Funding Interactions Inside the R&D Black Box

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    This paper is a first step toward closing the analytical gap in the extensive literature on the results of interactions between public and private R&D expenditures, and their joint effects on the economy. Econometric studies in this area report a plethora of sometimes confusing and frequently contradictory estimates of the response of company financed R&D to changes in the level and nature of public R&D expenditure, but the necessary theoretical framework within which the empirical results can be interpreted is seldom provided. A major cause of inconsistencies' in the empirical literature is the failure to recognize key differences among the various policy experiments' being considered depending upon the economy in which they are embedded, and the type of public sector R&D spending that is contemplated. Using a simple, stylized structural model, we identify the main channels of impact of public R&D. We thus can characterize the various effects, distinguishing between short-run and long-run impacts that would show up in simple regression analyses of nominal public and private R&D expenditure variables. Within the context of our simple model it is possible to offer interpretations that shed light on recent cross-section and panel data findings at both high (i.e. national) and low (specific technology area) levels of aggregation.

    The principle of equivalence and projective structure in space-times

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    This paper discusses the extent to which one can determine the space-time metric from a knowledge of a certain subset of the (unparametrised) geodesics of its Levi-Civita connection, that is, from the experimental evidence of the equivalence principle. It is shown that, if the space-time concerned is known to be vacuum, then the Levi-Civita connection is uniquely determined and its associated metric is uniquely determined up to a choice of units of measurement, by the specification of these geodesics. It is further demonstrated that if two space-times share the same unparametrised geodesics and only one is assumed vacuum then their Levi-Civita connections are again equal (and so the other metric is also a vacuum metric) and the first result above is recovered.Comment: 23 pages, submitted to Classical and Quantum Gravit

    Corals on seamounts

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