9,704 research outputs found
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Technological Change and Economy in the Epipalaeolithic: Assessing the Shift from Early to Middle Epipalaeolithic at Kharaneh IV
Epipalaeolithic hunter-gatherer communities in the Southern Levant exhibit numerous complex trends that suggest that the transition to the Neolithic was patchy and protracted. This paper explores the changing nature of occupation at the Epipalaeolithic site Kharaneh IV, Jordan, through an in-depth analysis of the lithic and faunal assemblages. Focusing on the analysis of a single deep sounding (unit AS42), we address how Kharaneh IV occupations link to the local landscape and environmental changes. As an aggregation site, Kharaneh IV represents an interesting locale to explore the changing nature of aggregation and social cohesion prior to the origins of agriculture, as well as changes in technology and subsistence between the Early and Middle Epipalaeolithic. We explore the tempo and nature of transition from one archaeological culture to the next through changes in technology and how this reflects the people making and using tools, to understand how foragers adapted to a changing landscape
Meat outside the freezer: Drying, smoking, salting and sealing meat in fat at an Epipalaeolithic megasite in eastern Jordan
Even though pivotal for understanding many aspects of human behaviour, preservation and storage of animal resources has not received great attention from archaeologists. One could argue that the main problem lies in the difficulties of demonstrating meat storage archaeologically due to the lack of direct evidence. This paper represents an attempt to refine zooarchaeological methods for the recognition of meat preservation and storage at prehistoric sites. Drawing on the faunal assemblage from Kharaneh IV, an Early/Middle Epipalaeolithic aggregation site in eastern Jordan, this study demonstrates that a combination of taphonomic and contextual analyses alongside ethnographic information may indeed lead archaeologists to insights not directly available from the archaeological record. The empirical evidence presented here contributes to the archaeological visibility of meat preservation and storage, providing a clearer concept of the nature of these practices in pre-agricultural societies
Pattern of extinction of the woolly mammoth in Beringia.
Extinction of the woolly mammoth in Beringia has long been subject to research and speculation. Here we use a new geo-referenced database of radiocarbon-dated evidence to show that mammoths were abundant in the open-habitat of Marine Isotope Stage 3 (∼45-30 ka). During the Last Glacial Maximum (∼25-20 ka), northern populations declined while those in interior Siberia increased. Northern mammoths increased after the glacial maximum, but declined at and after the Younger Dryas (∼12.9-11.5 ka). Remaining continental mammoths, now concentrated in the north, disappeared in the early Holocene with development of extensive peatlands, wet tundra, birch shrubland and coniferous forest. Long sympatry in Siberia suggests that humans may be best seen as a synergistic cofactor in that extirpation. The extinction of island populations occurred at ∼4 ka. Mammoth extinction was not due to a single cause, but followed a long trajectory in concert with changes in climate, habitat and human presence
Medication adherence in bipolar disorder: Understanding patients’ perspectives to inform intervention development
Bipolar Disorder is primarily treated with medication which can be effective in reducing relapse risk, however, treatment is complex and adherence is sub-optimal. People can face significant challenges in self-managing the condition. The aim of this thesis was to better understand patients’ perspectives of BD and its treatment. Then, to use both this knowledge and self-regulation and behaviour change theory to develop and test a novel intervention entitled Improving information for people with Bipolar Disorder (IBiD). Intervention mapping, a stepwise process was followed to develop intervention content, delivery and evaluation. A systematic review with meta-analysis (k=18) was conducted and revealed that interventions are effective in improving adherence, effects are durable and brief interventions may be more effective than longer programmes (Chapter 3). A qualitative study (Chapter 4) (n=12) revealed patients insights into the burden of illness, unmet information needs and also how to live well with BD. These findings informed the IBiD intervention, which was tested in a feasibility RCT in a sample of patients in an acute mental health setting (Chapters 5-7). The intervention can feasibly be delivered in this setting and was acceptable to patients. Aspects of the intervention and the study itself had self-reported positive outcomes, however a more targeted, longer intervention may be required to actually modify specific medication beliefs and adherence. In order to explore additional factors raised during these studies a cross-sectional study (n=57) into the associations between perceptions, adherence and involvement in treatment decisions was conducted. Experiences of involvement and preferences for this were high. Involvement was significantly associated with satisfaction with information and illness perceptions. Associations between involvement and adherence were inconsistent. The results of this research programme have important implications for both mental health services and the application of health and illness theory to mental health
Influence of carbon on intraband scattering in Mg(B1-xCx)2
We report data on the Hall coefficient (RH) of the carbon substituted
Mg(B1-xCx)2 single crystals with x in the range from 0 to 0.1. The temperature
dependences of RH obtained for the substituted crystals differ systematically
at low temperatures, but all of them converge to the value of 1.8 x 10^-10
m^3/C at room temperature. The RH(T) data together with results of the
thermoelectric power and electrical resistivity measurements are interpreted
within a quasi-classical transport approach, where the presence of four
different conducting sheets is considered. The main influence of the carbon
substitution on the transport properties in the normal state is associated with
enhanced scattering rates, rather than modified concentration of charge
carriers. Presumably the carbon substitution increases the electron-impurity
scattering mainly in the pi band.Comment: 16 pages, 3 figure
Sintering Effects on Microstructure and Electrical Properties of CaCu3Ti4O12 Ceramics
CCTO powders were prepared by solid state reaction and mechanochemically, respectively. Synthesized powders were characterized by XRD, FE-SEM and PSA techniques. The sinterability of CCTO powders was investigated by heating microscopy. Powders were uniaxially pressed into pellets and sintered up to 1100 °C, with heating rates of 2, 5, 10 and 20 °/min. The recorded shrinkage curves were used for choosing conventional and two step sintering (TSS) conditions. By TSS the samples were heated up to 1070 °C and after retention for 10 min cooled down to 1020 °C and kept for 20 h. The microstructure of CCTO ceramics sintered by conventional and TSS techniques was examined by FE-SEM method; the electrical properties were investigated in medium frequency (MF) range (42 Hz-5 MHz) and in the microwave (MW) range of frequencies. Electrical properties of the sintered CCTO ceramics were correlated to the samples microstructure. Finally, we have shown that appropriate choice of sintering conditions is important for preparation of high-quality CCTO ceramics with high dielectric permittivity in the kilohertz range as well as at the resonant frequency
25-Hydroxyvitamin D Threshold for the Effects of Vitamin D Supplements on Bone Density:Secondary Analysis of a Randomized Controlled Trial
Most trials of vitamin D supplementation have shown no benefits on bone density (BMD), though severe vitamin D deficiency causes osteomalacia which is associated with profound BMD deficits. Recently, the ViDA-BMD study from New Zealand demonstrated a threshold of baseline 25-hydroxyvitamin D (30 nmol/L) below which vitamin D supplementation did benefit BMD. We have now re-examined data from a similar trial in Aberdeen to determine whether a baseline 25-hydroxyvitamin D threshold of 30 nmol/L is also observed in that database. The Aberdeen study recruited 305 postmenopausal women in late winter and randomized them to receive placebo, vitamin D 400 IU/day or vitamin D 1000 IU/day over one year. As previously reported, BMD loss at the hip was reduced by vitamin D 1000 IU/day only, and there was no significant treatment effect of either dose at the lumbar spine. In the present analysis, when the trial participants were grouped according to whether their baseline 25-hydroxyvitamin D was ≤30 nmol/L or above this threshold, significant treatment effects were apparent at both the spine and hip in those with baseline 25-hydroxyvitamin D ≤30 nmol/L, but no significant effects were apparent in those with baseline 25-hydroxyvitamin D above this level. There was evidence of a similar threshold for effects on parathyroid hormone, but no groups showed changes in bone turnover markers during the study. It is concluded that vitamin D supplements only increase bone density in adults with nadir 25-hydroxyvitamin D ≤30 nmol/L. This moves us further towards a trial-based definition of vitamin D deficiency in adults with adequate calcium intakes, and suggests that supplement use should be targeted accordingly. Future trials of vitamin D supplementation should focus on individuals with 25-hydroxyvitamin D concentrations in this range
Synthesis and reductive chemistry of bimetallic and trimetallic rare-earth metallocene hydrides with (C5H4SiMe3)1− ligands
The reductive chemistry of [Cp\u272Ln(μ–H)(THF)x]y [Ln = Y, Dy, Tb; Cp\u27 = (C5H4SiMe3)1−; x = 2, 0 and y = 2, 3] was examined to determine if these hydrides would be viable precursors for 4fn5d1 Ln2+ ions that could form 5d1-5d1 metal–metal bonded complexes. The hydrides were prepared by reaction of the chlorides, [Cp\u272Ln(μ–Cl)]2, 1-Ln, with allylmagnesium chloride to form the allyl complexes, [Cp\u272Y(η3–C3H5)(THF)], 2-Ln, which were hydrogenolyzed. The solvent-free reaction of solid 2-Ln with 60 psi of H2 gas in a Fischer-Porter apparatus produced, in the Y case, the trimetallic species, [Cp\u272Y(μ–H)]3, 3-Y, and in the Dy and Tb cases, the bimetallic complexes [Cp\u272Ln(μ–H)(THF)]2, 4-Ln (Ln = Dy, Tb). The latter complexes could be converted to 3-Dy and 3-Tb by heating under vacuum. Isopiestic data indicate that 3-Y solvates to 4-Y in THF. Reductions of 4-Y, 4-Dy, and 4-Tb with KC8 in the presence of a chelate such as 2.2.2-cryptand or 18-crown-6 all gave reaction products with intense dark colors characteristic of Ln2+ ions. In the yttrium case, with either chelating agent, the dark green product gives a rhombic EPR spectrum (g1 = 2.01, g2 = 1.99, g3 = 1.98, A = 24.1 G) at 77 K. However, the only crystallographically-characterizable products obtainable from these solutions were Ln3+polyhydride anion complexes of composition, [K(chelate)]{[Cp\u272Ln(μ–H)]3(μ–H)}
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The Community Ecology of Herbivore Regulation in an Agroecosystem: Lessons from Complex Systems
AbstractWhether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem
Determinants of hand hygiene behaviour based on the Theory of Interpersonal Behaviour
Background: Many investigations into the determinants of hand hygiene (HH) behaviour have explored only individual predictors or were designed according to arguably overly simplistic models of behaviour. Consequently, important influences on HH behaviour, including habit and emotion, are sometimes neglected. This study is the first to employ the Theory of Interpersonal Behaviour as a comprehensive model for understanding the determinants of HH behaviour.
Method: A self-report questionnaire was conducted with staff from two large UK veterinary referral practices. Participants (n = 75) reported their HH behaviour and responded to statements rating the importance of social norms, self-protection, patient protection, time pressures, access to equipment, habit and disgust, to their HH behaviour.
Results: Regression analysis showed that, overall, determinants explained 46% of variance (p < .001) in self-reported HH behaviour, with time constraints being the strongest predictor (β = −.47, p < .001) followed by difficulty finding equipment (β = −.21, p = .05).
Discussion: Time constraints may be the most important influence on HH adherence among the determinants investigated. Future researchers should consider employing theoretical models to aid a more comprehensive understanding of the psychology underlying HH adherence and HH interventions
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