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This study provides an assessment of the temporal changes in ΔR, which is the local deviation from the global surface water marine reservoir effect (MRE), in the Point Barrow area of the Alaskan Arctic, a coastal archaeological area that has experienced severe erosion accelerated by global warming. A total of 26 samples were submitted for radiocarbon (14C) dating from eight secure Thule (AD 1000–1750) archaeological contexts, and specifically from archaeological features with paired processed seal and caribou bones that had been frozen in situ. This new approach towards ΔR estimation provides a best-fit local correction for the 14C dating of human populations by focusing on the marine mammal (seals) predominantly consumed by the Thule (Coltrain et al. 2016). The weighted-mean ΔR value on these pairs is 450 ± 84 yr, which is about 50 years less than the weighted-mean (506 ± 69 yr) for the Point Barrow area calculated through 14C measurements from four known-age bivalves collected in AD 1913 (McNeely et al. 2006). The effects of using this new ΔR value for calibration was assessed through the Bayesian chronological modeling of 54 14C measurements from samples of human skeletons interred in the Nuvuk cemetery at Point Barrow, the largest ancient cemetery in northwest Alaska and traditionally thought to date to the Thule and earlier Birnirk (AD 500–1000) periods.
Declining sea ice is expected to change the Arctic's physical and biological systems in ways that are difficult to predict. This study used stable isotope compositions (δ13C and δ15N) of archaeological, historic, and modern Pacific walrus (Odobenus rosmarus divergens) bone collagen to investigate the impacts of changing sea ice conditions on walrus diet during the last ~4000 yr. An index of past sea ice conditions was generated using dinocyst-based reconstructions from three locations in the northeastern Chukchi Sea. Archaeological walrus samples were assigned to intervals of high and low sea ice, and δ13C and δ15N were compared across ice states. Mean δ13C and δ15N values were similar for archaeological walruses from intervals of high and low sea ice; however, variability among walruses was greater during low-ice intervals, possibly indicating decreased availability of preferred prey. Overall, sea ice conditions were not a primary driver of changes in walrus diet. The diet of modern walruses was not consistent with archaeological low sea ice intervals. Rather, the low average trophic position of modern walruses (primarily driven by males), with little variability among individuals, suggests that trophic changes to this Arctic ecosystem are still underway or are unprecedented in the last ~4000 yr.
The cold, wet climate of the Arctic has led to the extraordinary preservation of archaeological sites and materials that offer important contributions to the understanding of our common cultural and ecological history. This potential, however, is quickly disappearing due to climate-related variables, including the intensification of permafrost thaw and coastal erosion, which are damaging and destroying a wide range of cultural and environmental archives around the Arctic. In providing an overview of the most important effects of climate change in this region and on archaeological sites, the authors propose the next generation of research and response strategies, and suggest how to capitalise on existing successful connections among research communities and between researchers and the public.
Engabreen is an outlet glacier of the Svartisen Ice Cap located in Northern Norway. It is a unique glacier due to the Svartisen Subglacial Laboratory which allows direct access to the glacier bed. In this study, we combine both sub- and supraglacial observations with ice-flow modelling in order to investigate conditions at the bed of Engabreen both spatially and temporally. We use the full-Stokes model Elmer/Ice and satellite-based surface-velocity maps from 2010 and 2014 to infer patterns of basal friction. Direct measurements of basal sliding and deformation of lower layers of the ice are used to adjust the ice viscosity and provide essential input to the setup of our model and influence the interpretation of the results. We find a clear seasonal cycle in the subglacial conditions at the higher elevation region of the study area and discuss this in relation to the subglacial hydrological system. Our results also reveal an area with an overdeepening where basal friction is significantly lower than elsewhere on the glacier all year round. We attribute this to either water pooling at the base, or saturated sediments and increased strain heating at this location which softens the ice further.
Nurses and respiratory therapists are seldom allowed to use automated external defibrillators (AED) during in-hospital cardiac arrest. This can result in significant time delays before defibrillation occurs and lower survival for cardiac arrest victims. We sought to identify barriers and facilitators to AED use by nurses and respiratory therapists.
We conducted semi-structured qualitative interviews with a purposeful sample of nurses and respiratory therapists. We developed the interview guide based on the constructs of the theory of planned behaviour, which elicits salient attitudes, social influences, and control beliefs potentially influencing the intent to use an AED. Interviews were recorded, transcribed verbatim, and analysed until achieving data saturation. Two independent reviewers performed inductive analyses to identify emerging categories and themes, and ranked them by frequency of the number of participants stating the topic.
Demographics for the 24 interviewees include mean age 40.5, 79.2% female, 87.5% performed cardiopulmonary resuscitation (CPR), 29.2% defibrillated a patient. Identified attitudes pertained to the timeliness of defibrillation, patient survival, simplicity of AED use, accuracy of rhythm recognition, and harm to self or others. Social influences consisted of physician and hospital administration support of AED use. Control beliefs included training on AED use, policy allowing AED use, familiarity with AED, and task burden during resuscitation.
Most nurses and respiratory therapists intended to use an AED if permitted to do so by a medical directive. Successful implementation would require educational initiatives focusing on safety and efficacy of AEDs, support from physicians and hospital administrators, and additional training on AED use.
The aim of the present study was to compare total food intake, total and relative edible plate waste and self-reported food likings between school lunch based on the new Nordic diet (NND) and packed lunch from home. In two 3-month periods in a cluster-randomised controlled unblinded cross-over study 3rd- and 4th-grade children (n 187) from two municipal schools received lunch meals based on NND principles and their usual packed lunch (control). Food intake and plate waste (n 1558) were calculated after weighing lunch plates before and after the meal for five consecutive days and self-reported likings (n 905) assessed by a web-based questionnaire. Average food intake was 6 % higher for the NND period compared with the packed lunch period. The quantity of NND intake varied with the menu (P < 0·0001) and was positively associated with self-reported likings. The edible plate waste was 88 (sd 80) g for the NND period and 43 (sd 60) g for the packed lunch period whereas the relative edible plate waste was no different between periods for meals having waste (n 1050). Edible plate waste differed between menus (P < 0·0001), with more waste on soup days (36 %) and vegetarian days (23 %) compared with the packed lunch period. Self-reported likings were negatively associated with percentage plate waste (P < 0·0001). The study suggests that portion sizes need to be considered in new school meal programmes. New strategies with focus on reduction of plate waste, children's likings and nutritious school meals are crucial from both a nutritional, economic and environmental point of view.
Recent Genome-Wide Association Studies (GWAS) have identified four low-penetrance ovarian cancer susceptibility loci. We hypothesized that further moderate- or low-penetrance variants exist among the subset of single-nucleotide polymorphisms (SNPs) not well tagged by the genotyping arrays used in the previous studies, which would account for some of the remaining risk. We therefore conducted a time- and cost-effective stage 1 GWAS on 342 invasive serous cases and 643 controls genotyped on pooled DNA using the high-density Illumina 1M-Duo array. We followed up 20 of the most significantly associated SNPs, which are not well tagged by the lower density arrays used by the published GWAS, and genotyping them on individual DNA. Most of the top 20 SNPs were clearly validated by individually genotyping the samples used in the pools. However, none of the 20 SNPs replicated when tested for association in a much larger stage 2 set of 4,651 cases and 6,966 controls from the Ovarian Cancer Association Consortium. Given that most of the top 20 SNPs from pooling were validated in the same samples by individual genotyping, the lack of replication is likely to be due to the relatively small sample size in our stage 1 GWAS rather than due to problems with the pooling approach. We conclude that there are unlikely to be any moderate or large effects on ovarian cancer risk untagged by less dense arrays. However, our study lacked power to make clear statements on the existence of hitherto untagged small-effect variants.
To examine the impact of a 6-month participatory and empowerment-based intervention study on employees’ dietary habits and on changes in the canteen nutrition environment.
Worksites were stratified by company type and by the presence or absence of an in-house canteen, and randomly allocated to either an intervention group (five worksites) or a minimum intervention control group (three worksites). The study was carried out in partnership with a trade union and guided by an ecological framework targeting both individual and environment levels. Outcome measures included: (i) changes in employees’ dietary habits derived from 4 d pre-coded food diaries of a group of employees at the worksites (paired-data structure); and (ii) the canteen nutrition environment as identified by aggregating chemical nutritional analysis of individual canteen lunches (different participants at baseline and at endpoint).
Eight blue-collar worksites (five of these with canteens).
In the intervention group (n 102), several significant positive nutritional effects were observed among employees, including a median daily decrease in intake of fat (−2·2 %E, P = 0·002) and cake and sweets (−18 g/10 MJ, P = 0·002) and a median increase in intake of dietary fibre (3 g/10 MJ, P < 0·001) and fruit (55 g/d, P = 0·007 and 74 g/10 MJ, P = 0·009). With regard to the canteen nutrition environment, a significant reduction in the percentage of energy obtained from fat was found in the intervention group (median difference 11 %E, P < 0·001, n 144).
The present study shows that moderate positive changes in dietary patterns can be achieved among employees in blue-collar worksites.
The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.
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