80 research outputs found
From icon of empire to national emblem: new evidence for the fallow deer of Barbuda
Barbuda and Antigua's national animal is the fallow deer, Dama dama dama, a species native to the eastern Mediterranean that has been transported around the world by people during the last 8,000 years. The timing and circumstances by which fallow deer came to be established on Barbuda are currently uncertain but, by examining documentary, osteological and genetic evidence, this paper will consider the validity of existing theories. It will review the dynamics of human-Dama relationships from the 1500s AD to the present day and consider how the meaning attached to this species has changed through time: from a symbol of colonial authority and dominance, to a 'walking larder' after the slave emancipation of 1834, and now an important part of the island's economy and cultural heritage that requires careful management
Disequilibrium, adaptation and the Norse settlement of Greenland
This research was supported by the University of Edinburgh ExEDE Doctoral Training Studentship and NSF grant numbers 1202692 and 1140106.There is increasing evidence to suggest that arctic cultures and ecosystems have followed non-linear responses to climate change. Norse Scandinavian farmers introduced agriculture to sub-arctic Greenland in the late tenth century, creating synanthropic landscapes and utilising seasonally abundant marine and terrestrial resources. Using a niche-construction framework and data from recent survey work, studies of diet, and regional-scale climate proxies we examine the potential mismatch between this imported agricultural niche and the constraints of the environment from the tenth to the fifteenth centuries. We argue that landscape modification conformed the Norse to a Scandinavian style of agriculture throughout settlement, structuring and limiting the efficacy of seasonal hunting strategies. Recent climate data provide evidence of sustained cooling from the mid thirteenth century and climate variation from the early fifteenth century. Archaeological evidence suggests that the Norse made incremental adjustments to the changing sub-arctic environment, but were limited by cultural adaptations made in past environments.Publisher PDFPeer reviewe
Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study
Background Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.Methods In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186.Findings Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78 center dot 6%] female patients and 4922 [21 center dot 4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1 center dot 4 [IQR 0 center dot 6-3 center dot 4]) compared with the prepandemic phase (2 center dot 0 [0 center dot 9-3 center dot 7]; p<0 center dot 0001) and pandemic decrease phase (2 center dot 3 [1 center dot 0-5 center dot 0]; p<0 center dot 0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69 center dot 0%] of 3704 vs 1515 [71 center dot 5%] of 2119; OR 1 center dot 1 [95% CI 1 center dot 0-1 center dot 3]; p=0 center dot 042), lymph node metastases (343 [9 center dot 3%] vs 264 [12 center dot 5%]; OR 1 center dot 4 [1 center dot 2-1 center dot 7]; p=0 center dot 0001), and tumours at high risk of structural disease recurrence (203 [5 center dot 7%] of 3584 vs 155 [7 center dot 7%] of 2006; OR 1 center dot 4 [1 center dot 1-1 center dot 7]; p=0 center dot 0039).Interpretation Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation.Funding None.Copyright (c) 2023 Published by Elsevier Ltd. All rights reserved
Dynamics of ovarian maturation during the reproductive cycle of Metynnis maculatus, a reservoir invasive fish species (Teleostei: Characiformes)
Risk assessment of non-native fishes in the catchment of the largest Central-European shallow lake (Lake Balaton, Hungary)
Gradient Elastodamage Model for Quasi-Brittle Materials with an Evolving Internal Length
The article presents a new approach based on a strain gradient damage constitutive law for modeling quasi-brittle materials such as concrete. The authors use a weak type nonlocal formulation of the problem, relying on Mindlin's Form II strain gradient elasticity theory. Gibbs free energy is used and the influence of the positive and negative principal strains to damage evolution is separated. Additional energy dissipation due to the gradient of the positive principal strains is introduced. The model requires an internal length, which is treated as an internal variable dependent on the level of damage. The study shows that the internal length increases with damage, corroborating available experimental results. Calibration of the gradient internal length evolution with damage is established through experimental data from two independent tests: a uniaxial tension or compression test to establish the evolution of damage, and a four-point bending (loading-unloading) test to relate the variation of the internal length with the accumulated level of damage. Anumerical analysis of the response of a concrete beamspecimen under four-point bending is presented to describe the calibration procedure. (C) 2014 American Society of Civil Engineers
A numerical model based on nonconvex-nonsmooth optimization for the simulation of bending tests on composite slabs with profiled steel sheeting
It is well known that the Calculation Of the ultimate strength of composite concrete slabs with profiled steel sheeting requires the determination of the longitudinal shear resistance which depends on the quality of the bond at the steel sheeting-concrete interface. According to Eurocode 4, the longitudinal shear strength of the composite concrete slabs is calculated through analytical relationships which are based, however, oil coefficients determined experimentally through a series of full-scale bending tests. In this paper a numerical model is proposed that is able to Simulate the above experimental procedure. For the modeling of the shear bonding between the concrete and the profiled sheeting, a nonmonotone law involving vertical and softening branches is used. The parameters describing this law are calculated exploiting experimentally obtained values. However, this complex shape of (lie shear bonding law leads to a hemivariational inequality mathematical formulation. For its numerical treatment, a numerical procedure is presented that uses tools from the theory of nonconvex-nonsmooth energy optimization. The results obtained by the proposed methodology are compared with those obtained by experimental testing. It is found that the numerical results are in a good agreement with the corresponding experimental ones. (C) 2009 Elsevier Ltd. All rights reserved
Structural Integrity of Steel Constructions under Earthquake actions: activity of COST-C12/WG2
, Patras, Greec
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