697 research outputs found

    Predation research with electronic tagging

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    Predation is a fundamental aspect of ecology that drives ecosystem structure and function. A better understanding of predation can be facilitated by using electronic tags that log or transmit positions of predator or prey species in natural settings, however, there are special considerations that must be made to avoid biased estimates. We provide an overview of the tools available for studying predation with electronic tags including the tag types and analytical tools that can be used to identify where, when and how prey are killed by predators. We also discuss considerations for experimental design when studying predation using electronic tags, including how to minimize effects of capture and tagging procedures. Ongoing innovation and integration of sensors for tags will provide more detailed data about the performance of tagged predators and the fate of tagged prey. Where analysts can effectively resolve the timing of predation using state-of-the-art tags and analytical tools, we foresee exciting advances in our understanding of animal demographics, evolutionary trajectories and management systems. Prospects to develop new tools and approaches for tracking predation while designing studies to more effectively limit bias are an important frontier for understanding ecosystems and addressing human–wildlife conflicts. Given great uncertainties about environmen-tal change and intensifying conflicts between humans and predators, effective study designs integrating electronic tagging to study predation have a promising future in fundamental and applied ecologypublishedVersio

    Behavioural response of brown trout (Salmo trutta) to total dissolved gas supersaturation in a regulated river

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    Total dissolved gas supersaturation from dams and power stations is a chronic freshwater pollutant that is toxic to animals with aquatic respiration. Laboratory ecotoxicology experiments have revealed capacity for captive fishes to saturoregulate by moving deeper, but field ecotoxicology research is largely lacking. We instrumented 94 brown trout in the Rysstad basin of the Otra River, Norway, with depth sensor acoustic transmitters and monitored their movements for 10 months. We found that the depths used by the trout largely protected them from the effects of total dissolved gas supersaturation, which ranged from 96% to 133% total gas pressure during the study. The depth use of fish was affected by sun position, lunar phase and spatial position in the river (i.e., available depth), and there was an extremely weak effect of total dissolved gas supersaturation that was counterintuitive (i.e., positive slope, movement toward surface). Depth traces of the fish revealed that nine fish died during the study, mostly coinciding with the first wave of supersaturation, consistent with observations of untagged dead fish with signs of gas bubble trauma found on the river bottom during this period (May-June). Overall, tagged trout exposure to total dissolved gas supersaturation depended on their use of depth, but responses to waves of extreme supersaturation at supraphysiological levels were weak and biologically insignificant, with individual variation and spatial position in the river most important in the model. Exposure to total dissolved gas supersaturation was mediated by individual differences in habitat use, which may be linked to activity and other traits that determine overall vulnerability to exposure to total dissolved gas supersaturation.publishedVersio

    Gastric cancer and Helicobacter pylori: a combined analysis of 12 case control studies nested within prospective cohorts

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    BACKGROUND: The magnitude of the association between Helicobacter pylori and incidence of gastric cancer is unclear. H pylori infection and the circulating antibody response can be lost with development of cancer; thus retrospective studies are subject to bias resulting from classifi- cation of cases as H pylori negative when they were infected in the past. AIMS: To combine data from all case control studies nested within prospective cohorts to assess more reliably the relative risk of gastric cancer associated with H pylori infection.To investigate variation in relative risk by age, sex, cancer type and subsite, and interval between blood sampling and cancer diagnosis. METHODS: Studies were eligible if blood samples for H pylori serology were collected before diagnosis of gastric cancer in cases. Identified published studies and two unpublished studies were included. Individual subject data were obtained for each. Matched odds ratios (ORs) and 95% confidence intervals (95% CI) were calculated for the association between H pylori and gastric cancer. RESULTS: Twelve studies with 1228 gastric cancer cases were considered. The association with H pylori was restricted to noncardia cancers (OR 3.0; 95% CI 2.3–3.8) and was stronger when blood samples for H pylori serology were collected 10+ years before cancer diagnosis (5.9; 3.4–10.3). H pylori infection was not associated with an altered overall risk of cardia cancer (1.0; 0.7–1.4). CONCLUSIONS: These results suggest that 5.9 is the best estimate of the relative risk of non-cardia cancer associated with H pylori infection and that H pylori does not increase the risk of cardia cancer. They also support the idea that when H pylori status is assessed close to cancer diagnosis, the magnitude of the non-cardia association may be underestimated

    A Message Service for Opportunistic Computing in Disconnected MANETs

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    International audienceDisconnected mobile ad hoc networks (or D-MANETs) are partially or intermittently connected wireless networks in which instant end-to-end connectivity between any pair of mobile hosts is never guaranteed. Recent advances in delay/disruption-tolerant networking make it possible to support communication in such conditions, but designing and implementing distributed applications for D-MANETs is still a challenging task. Middleware systems such as the Java Message Service (JMS) have made application development easy and cost-effective in traditional wired networks. In this paper, we introduce JOMS (Java Opportunistic Message Service), a JMS provider specifically designed for D-MANETs, and with which pre-existing or new JMS-based applications can be easily deployed in such networks

    Syn‐rift sediment gravity flow deposition on a Late Jurassic fault‐terraced slope, northern North Sea

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    Structurally controlled bathymetry in rifts has a significant influence on sediment routing pathways and depositional architecture of sediment gravity flow deposits. In contrast to rift segments characterized by crustal-scale half-grabens, the tectono-stratigraphic evolution of deep-water rift domains characterised by distributed faulting on narrow fault terraces has received little attention. We use 3D broadband seismic data, calibrated by boreholes, from the Lomre and Uer terraces in the northern North Sea rift to investigate Late Jurassic syn-rift sediment gravity flow systems on fault-terraced slopes. The sediment gravity flow fairways were sourced from hinterland drainages via basin margin deltaic systems on the Horda Platform to the southeast. The deep-water sedimentary systems evolve from initial, widespread submarine channelized lobe complexes, through submarine channels, to incised submarine canyons. This progressive confinement of the sediment gravity flow system was concomitant with progressive localization of strain onto the main terrace-bounding faults. Although the normal fault network on the terraces has local impact on deep-water sediment transport and the architecture of gravity flow deposits, it is the regional basin margin to rift axis gradient that dominantly controls deep-water sediment routing. Furthermore, the gravity flow deposits on the Lomre and Uer terraces were predominantly sourced by rift margin deltaic systems, not from erosion of local uplifted footwall crests, emphasising the significance of hinterland catchments in the development of volumetrically significant deep-water syn-rift depositional systems

    Prevention of Neural Tube Defects: A Cross-Sectional Study of the Uptake of Folic Acid Supplementation in Nearly Half a Million Women

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    BACKGROUND: Taking folic acid supplements before pregnancy to reduce the risk of a neural tube defect (NTD) is especially important in countries without universal folic acid fortification. The extent of folic acid supplementation among women who had antenatal screening for Down's syndrome and NTDs at the Wolfson Institute of Preventive Medicine, London between 1999 and 2012 was assessed. METHODS AND FINDINGS: 466,860 women screened provided details on folic acid supplementation. The proportion of women who took folic acid supplements before pregnancy was determined according to year and characteristics of the women. The proportion of women taking folic acid supplements before pregnancy declined from 35% (95% CI 34%-35%) in 1999-2001 to 31% (30%-31%) in 2011-2012. 6% (5%-6%) of women aged under 20 took folic acid supplements before pregnancy compared with 40% of women aged between 35 and 39. Non-Caucasian women were less likely to take folic acid supplements before pregnancy than Caucasian women; Afro-Caribbean 17% (16%-17%), Oriental 25% (24%-25%) and South Asian 20% (20%-21%) compared with 35% (35%-35%) for Caucasian women. 51% (48%-55%) of women who previously had an NTD pregnancy took folic acid supplements before the current pregnancy. CONCLUSIONS: The policy of folic acid supplementation is failing and has led to health inequalities. This study demonstrates the need to fortify flour and other cereal grain with folic acid in all countries of the world

    Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019

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    Background Given the projected trends in population ageing and population growth, the number of people with dementia is expected to increase. In addition, strong evidence has emerged supporting the importance of potentially modifiable risk factors for dementia. Characterising the distribution and magnitude of anticipated growth is crucial for public health planning and resource prioritisation. This study aimed to improve on previous forecasts of dementia prevalence by producing country-level estimates and incorporating information on selected risk factors. Methods We forecasted the prevalence of dementia attributable to the three dementia risk factors included in the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 (high body-mass index, high fasting plasma glucose, and smoking) from 2019 to 2050, using relative risks and forecasted risk factor prevalence to predict GBD risk-attributable prevalence in 2050 globally and by world region and country. Using linear regression models with education included as an additional predictor, we then forecasted the prevalence of dementia not attributable to GBD risks. To assess the relative contribution of future trends in GBD risk factors, education, population growth, and population ageing, we did a decomposition analysis. Findings We estimated that the number of people with dementia would increase from 57·4 (95% uncertainty interval 50·4–65·1) million cases globally in 2019 to 152·8 (130·8–175·9) million cases in 2050. Despite large increases in the projected number of people living with dementia, age-standardised both-sex prevalence remained stable between 2019 and 2050 (global percentage change of 0·1% [–7·5 to 10·8]). We estimated that there were more women with dementia than men with dementia globally in 2019 (female-to-male ratio of 1·69 [1·64–1·73]), and we expect this pattern to continue to 2050 (female-to-male ratio of 1·67 [1·52–1·85]). There was geographical heterogeneity in the projected increases across countries and regions, with the smallest percentage changes in the number of projected dementia cases in high-income Asia Pacific (53% [41–67]) and western Europe (74% [58–90]), and the largest in north Africa and the Middle East (367% [329–403]) and eastern sub-Saharan Africa (357% [323–395]). Projected increases in cases could largely be attributed to population growth and population ageing, although their relative importance varied by world region, with population growth contributing most to the increases in sub-Saharan Africa and population ageing contributing most to the increases in east Asia. Interpretation Growth in the number of individuals living with dementia underscores the need for public health planning efforts and policy to address the needs of this group. Country-level estimates can be used to inform national planning efforts and decisions. Multifaceted approaches, including scaling up interventions to address modifiable risk factors and investing in research on biological mechanisms, will be key in addressing the expected increases in the number of individuals affected by dementia.F Carvalho and E F Fernandes acknowledge support from the University of Porto (UID/MULTI/04378/2019 and UID/QUI/50006/2019 with funding from FCT/MCTES through national funds). L F S Castro-de-Araujo acknowledges support from the Medical Research Council (London; grant number MC_PC_MR/T03355X/1). V M Costa acknowledges her grant (SFRH/BHD/110001/2015), received by Portuguese national funds through Fundação para a CiĂȘncia e Tecnologia (FCT), IP, under the Norma TransitĂłria (DL57/2016/CP1334/CT0006). A Douiri acknowledges support from the NIHR Applied Research Collaboration (ARC) South London at King's College Hospital NHS Foundation Trust and the Royal College of Physicians, as well as the support from the NIHR Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London. N Ghith acknowledges her salary as a postdoc is covered by a grant to her research group provided by Novo Nordisk Foundation. V K Gupta and V B Gupta acknowledge funding support from National Health and Medical Research Council (NHMRC), Australia. S Haque acknowledges support from Jazan University, Saudi Arabia, for providing access to the Saudi Digital Library for this study. C Herteliu is partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation (CNDS-UEFISCDI, project number PN-III-P4-ID-PCCF-2016-0084). Y J Kim was supported by the Research Management Centre, Xiamen University, Malaysia (No. XMUMRF/2020-C6/ITCM/0004). M KivimĂ€ki was supported by the MRC (S011676) and the Wellcome Trust (221854/Z/20/Z). M Kumar acknowledges support from Fogarty International Center (K43 TW010716-04). S Lorkowski acknowledges institutional support from the Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD) Halle-Jena-Leipzig (Germany; German Federal Ministry of Education and Research, grant agreement number 01EA1808A). S Mondello was supported by the Italian Ministry of Health (GR-2013-02354960). A Raggi acknowledges support from a grant from the Italian Ministry of Health (Ricerca Corrente, Fondazione Istituto Neurologico C. Besta, Linea – Outcome Research: dagli Indicatori alle Raccomandazioni Cliniche). D A S Silva acknowledges support from Coordenação de Aperfeiçoamento de Pessoal de NĂ­vel Superior, Brasil (CAPES; Finance Code 001 / CAPES-PRINT). J P Silva acknowledges support from the Applied Molecular Biosciences Unit (UCIBIO; grant number UIDB/04378/2020), supported through Portuguese national funds via FCT/MCTES.publishedVersio

    DNA Methylation Score as a Biomarker in Newborns for Sustained Maternal Smoking during Pregnancy

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    Background: Maternal smoking during pregnancy, especially when sustained, leads to numerous adverse health outcomes in offspring. Pregnant women disproportionately underreport smoking and smokers tend to have lower follow-up rates to repeat questionnaires. Missing, incomplete, or inaccurate data on presence and duration of smoking in pregnancy impairs identification of novel health effects and limits adjustment for smoking in studies of other pregnancy exposures. An objective biomarker in newborns of maternal smoking during pregnancy would be valuable. Objectives: We developed a biomarker of sustained maternal smoking in pregnancy using common DNA methylation platforms. Methods: Using a dimension reduction method, we developed and tested a numeric score in newborns to reflect sustained maternal smoking in pregnancy from data on cotinine, a short-term smoking biomarker measured mid-pregnancy, and Illumina450K cord blood DNA methylation from newborns in the Norwegian Mother and Child Cohort Study (MoBa). Results: This score reliably predicted smoking status in the training set (n = 1,057; accuracy = 96%, sensitivity = 80%, specificity = 98%). Sensitivity (58%) was predictably lower in the much smaller test set (n = 221), but accuracy (91%) and specificity (97%) remained high. Reduced birth weight, a well-known effect of maternal smoking, was as strongly related to the score as to cotinine. A three-site score had lower, but acceptable, performance (accuracytrain = 82%, accuracytest = 83%). Conclusions: Our smoking methylation score represents a promising novel biomarker of sustained maternal smoking during pregnancy easily calculated with Illumina450K or IlluminaEPIC data. It may help identify novel health impacts and improve adjustment for smoking when studying other risk factors with more subtle effects.publishedVersio
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