34,549 research outputs found
IntCal04 terrestrial radiocarbon age calibration, 0-26 cal kyr BP
No full textA new calibration curve for the conversion of radiocarbon ages to calibrated (cal) ages has been constructed and internationally ratified to replace ImCal98, which extended from 0-24 cal kyr BP (Before Present, 0 cal BP = AD 1950). The new calibration data set for terrestrial samples extends from 0-26 cal kyr BP, but with much higher resolution beyond 11.4 cal kyr BP than ImCal98. Dendrochronologically-dated tree-ring samples cover the period from 0-12.4 cal kyr BP. Beyond the end of the tree rings, data from marine records (corals and foraminifera) are converted to the atmospheric equivalent with a site-specific marine reservoir correction to provide terrestrial calibration from 12.4-26.0 cal kyr BP. A substantial enhancement relative to ImCal98 is the introduction of a coherent statistical approach based on a random walk model, which takes into account the uncertainty in both the calendar age and the C-14 age to calculate the underlying calibration curve (Buck and Blackwell, this issue). The tree-ring data sets, sources of uncertainty, and regional offsets are discussed here. The marine data sets and calibration curve for marine samples from the surface mixed layer (Marine 04) are discussed in brief, but details are presented in Hughen et al. (this issue a). We do not make a recommendation for calibration beyond 26 cal kyr BP at this time; however, potential calibration data sets are compared in another paper (van der Plicht et al., this issue)
SHCal13 Southern Hemisphere calibration, 0–50,000 years cal BP
No full textThe Southern Hemisphere SHCal04 radiocarbon calibration curve has been updated with the addition of new data sets extending measurements to 2145 cal BP and including the ANSTO Younger Dryas Huon pine data set. Outside the range of measured data, the curve is based upon the Northern Hemisphere data sets as presented in IntCal13, with an interhemispheric offset averaging 43 ± 23 yr modeled by an autoregressive process to represent the short-term correlations in the offset
Modelling the integration of BP and IT using business process simulation
No full textInformation Technology (IT) and Business Process (BP) communities argues that the use of IT to support business processes can bring a number of benefits to the organisation. Most of these benefits, however, can only be seen after the implementation of such technology. Moreover, there are many cases where the benefits brought by the implementation of IT do not fulfil the organisation’s expectations. One reason of this may happen is because research in BP and IS domains show little indication of which modelling methods, techniques or tools can help organisations to foresee the benefits of the integration of IT with BP. This paper describes the insights gained during a UK funded research project, namely ASSESS-IT, which used simulation techniques to address this problem. Considering IT as a two layered system, namely Information Systems (IS) and Computer Networks (CN), ASSESS-IT aimed to depict the benefits that new IT may bring to the BP. This paper uses the outcomes derived from ASSESS-IT to suggest that, in some cases; the relationship between BP and IT could be better understood by looking at the relationship between BP and IS alone. It then proposes an alternative simulation framework, namely ISBPS, that provides the means to develop simulation models that portray quantifiable metrics of the integration of BP and IS, offering in this way an alternative mechanism that can help BP and IS analyst to foresee the benefits that the insertion of a given IS design may bring to the organisational processes
Climate forcing due to the 8200 cal yr BP event observed at Early Neolithic sites in the eastern Mediterranean
No full textWe explore the hypothesis that the abrupt drainage of Laurentide lakes and associated rapid switch of the North Atlantic thermohaline circulation 8200 yr ago had a catastrophic influence on Neolithic civilisation in large parts of southeastern Europe, Anatolia, Cyprus, and the Near East. The event at 8200 cal yr BP is observed in a large number of high-resolution climate proxies in the Northern Hemisphere, and in many cases corresponds to markedly cold and arid conditions. We identify the relevant archaeological levels of major Neolithic settlements in Central Anatolia, Cyprus, Greece and Bulgaria, and examine published stratigraphic, architectural, cultural and geoarchaeological studies for these sites. The specific archaeological events and processes we observe at a number of these sites during the study interval 8400–8000 cal yr BP lead us to refine some previously established Neolithisation models. The introduction of farming to South-East Europe occurs in all study regions (Thrace, Macedonia, Thessaly, Bulgaria) near 8200 cal yr BP. We observe major disruptions of Neolithic cultures in the Levant, North Syria, South-East Anatolia, Central Anatolia and Cyprus, at the same time. We conclude that the 8200 cal yr BP aridity event triggered the spread of early farmers, by different routes, out of West Asia and the Near East into Greece and Bulgaria
Explicating Ethical Corporate Marketing. Insights from the BP Deepwater Horizon Catastrophe: The Ethical Brand that Exploded and then Imploded
No full textBP brand, Brand positioning, Deepwater horizon, Ethical corporate marketing, Corporate marketing, Ethical corporate identity, Sustainable entrepreneurship, Sustainability, Ethical corporate brands,
BP’s use of posture to respond to the deepwater horizon crisis
No full textThis paper focuses on the posture the oil company BP adopted when faced with a legitimacy crisis during one of the worst environmental disasters in history. Against a backdrop of a discussion of the rhetorical aspects of image repair discourse and organisational legitimacy, Hearit’s strategy of corporate apologia was employed to determine the posture BP adopted in relation to the crisis. This paper adds to the literature on image repair strategies by heeding a call by Hearit for the context within which corporate apologia takes place to be taken account of, an approach that warrants a distinct line of research. The literature was further extended by complementing Hearit's strategy with semiotics and analysing its use in both the annual and sustainability reports. The additional focus on the sustainability reports is important, due to the high premium placed on sustainability in the changing business environment. On a practical level this paper contributes to an understanding of how organisations use sustainability reports to respond to legitimacy challenges
Autoantibody profile differentiates BP phenotypes
No full textBullous pemphigoid (BP) is a major autoimmune blistering skin disorder, in which a majority of the autoantibodies (autoAbs) target the juxtamembranous extracellular noncollagenous 16A domain (NC16A) domain of hemidesmosomal collagen XVII. BP-autoAbs may target regions of collagen XVII other than the NC16A domain; however, correlations between epitopes of BP-autoAbs and clinical features have not been fully elucidated. To address correlations between the clinical features and specific epitopes of BP-autoAbs, we evaluated the epitope profiles of BP-autoAbs in 121 patients. A total of 87 patients showed a typical inflammatory phenotype with erythema and autoAbs targeting the anti-NC16A domain, whereas 14 patients showed a distinct noninflammatory phenotype, in which autoAbs specifically targeted the midportion of collagen XVII, but not NC16A. Interestingly, this group clinically showed significantly reduced erythema associated with scant lesional infiltration of eosinophils. Surprisingly, 7 of the 14 cases (50.0%) received dipeptidyl peptidase-IV inhibitors for the treatment of diabetes. Dipeptidyl peptidase-IV inhibitors were used in 3 of 76 (3.9%) typical cases of BP with autoAbs targeting NC16A; thus, dipeptidyl peptidase-IV inhibitors are thought to be involved in the development of atypical noninflammatory BP. This study shows that the autoAb profile differentiates between inflammatory and noninflammatory BP, and that noninflammatory BP may be associated with dipeptidyl peptidase-IV inhibitors
On the non-attractive character of gravity in f(R) theories
No full text©2013 IOP Publishing Ltd and Sissa Medialab srl
This work has been supported by MINECO (Spain) project numbers FIS2011-23000, FPA2011-27853-C02-01 and Consolider-Ingenio MULTIDARK CSD2009-00064. AdlCD also acknowledges financial support from Marie Curie - Beatriu de Pinós contract BP-B00195, Generalitat de Catalunya and ACGC, University of Cape Town.Raychaudhuri equation is found provided that particular energy conditions are assumed and regardless the considered solution of the Einstein's equations. This fact is usually interpreted as a manifestation of the attractive character of gravity. Nevertheless, a positive contribution to Raychaudhuri equation from space-time geometry should occur since this is the case in an accelerated expanding Robertson-Walker model for congruences followed by fundamental observers. Modified gravity theories provide the possibility of a positive contribution although the standard energy conditions are assumed. We address this important issue in the context of f(R) theories, deriving explicit upper bounds for the contribution of space-time geometry to the Raychaudhuri equation. Then, we examine the parameter constraints for some paradigmatic f(R) models in order to ensure a positive contribution to this equation. Furthermore, we consider the implications of these upper bounds in the equivalent formulation of f(R) theories as a Brans-Dicke model.MINECO (Spain)Consolider-Ingenio MULTIDARKMarie Curie - Beatriu de PinosGeneralitat de CatalunyaACGC, University of Cape TownDepto. de Física TeóricaFac. de Ciencias FísicasTRUEpu
Re-identification of c. 15 700 cal yr BP tephra bed at Kaipo Bog, eastern North Island: implications for dispersal of Rotorua and Puketarata tephra beds.
No full textA 10 mm thick, c. 15 700 calendar yr BP (c. 13 100 14C yr BP) rhyolitic tephra bed in the well-studied montane Kaipo Bog sequence of eastern North Island was previously correlated with Maroa-derived Puketarata Tephra. We revise this correlation to Okataina-derived Rotorua Tephra based on new compositional data from biotite phenocrysts and glass. The new correlation limits the known dispersal of Puketarata Tephra (sensu stricto, c. 16 800 cal yr BP) and eliminates requirements to either reassess its age or to invoke dual Puketarata eruptive events. Our data show that Rotorua Tephra comprises two glass-shard types: an early-erupted low-K2O type that was dispersed mostly to the northwest, and a high-K2O type dispersed mostly to the south and southeast, contemporary with late-stage lava extrusion. Late-stage Rotorua eruptives contain biotite that is enriched in FeO compared with biotite from Puketarata pyroclastics. The occurrence of Rotorua Tephra in Kaipo Bog (100 km from the source) substantially extends its known distribution to the southeast. Our analyses demonstrate that unrecognised syn-eruption compositional and dispersal changes can cause errors in fingerprinting tephra deposits. However, the compositional complexity, once recognised, provides additional fingerprinting criteria, and also documents magmatic and dispersal processes
Link prediction in author collaboration network based on BP neural network
No full textRecently, more and more authors have been encouraged for collaboration because it often produces good results. However, the author collaboration network contains experts in various research directions within various fields, and it is difficult for individual authors to decide which authors are best suited to their expertise. This paper uses the relationships among authors to predict new relationships that may arise, recommending each author with the collaborators they may be interested in. The data source comes from 4-year data in DBLP from 2001 to 2004. After data cleaning, the training set and test set are constructed and then used BP neural network to build model. At the same time, this article compares the performance with Logistic Regression, SVM and Random Forest. The experiment shows that the BP neural network can get better result, and it is feasible to predict links in the author collaboration network
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