umu.sePublications
2345 201 - 203 of 203
rss atomLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
  • Grafström, Anton
    et al.
    Ekström, Magnus
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden.
    Jonsson, Bengt Gunnar
    Esseen, Per-Anders
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ståhl, Göran
    On combining independent probability samples2019In: Survey Methodology, ISSN 0714-0045, E-ISSN 1492-0921, Vol. 45, no 2, p. 349-364Article in journal (Refereed)
    Abstract [en]

    Merging available sources of information is becoming increasingly important for improving estimates of population characteristics in a variety of fields. In presence of several independent probability samples from a finite population we investigate options for a combined estimator of the population total, based on either a linear combination of the separate estimators or on the combined sample approach. A linear combination estimator based on estimated variances can be biased as the separate estimators of the population total can be highly correlated to their respective variance estimators. We illustrate the possibility to use the combined sample to estimate the variances of the separate estimators, which results in general pooled variance estimators. These pooled variance estimators use all available information and have potential to significantly reduce bias of a linear combination of separate estimators.

  • Buckland, Philip I.
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies, Environmental Archaeology Lab.
    Bateman, Mark D.
    Department of Geography, University of Sheffield, Sheffield S10 2TN, UK.
    Bennike, Ole
    GEUS Geological Survey of Denmark and Greenland, ØsterVoldgade 10, Copenhagen 1350, Denmark.
    Buckland, Paul C.
    Chase, Brian M.
    Institut des Sciences de l’Evolution-Montpellier (ISEM), Universite´ de Montpellier, CNRS, EPHE, IRD, Bat 22, CC061, Place Euge`ne Bataillon, 34095 Montpellier cedex 5, France.
    Frederick, Charles
    6Department of Geography and the Environment, The University of Texas at Austin, Austin, TX, USA.
    Greenwood, Malcolm
    Department of Geography, Loughborough University, Leics LE11 3TU, UK.
    Murton, Julian
    Department of Geography, University of Sussex, Brighton BN1 9RH, UK.
    Murton, Della
    Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
    Panagiotakopulu, Eva
    Institute of Geography, University of Edinburgh, Drummond Street, Edinburgh EH8 9XP, UK.
    Mid-Devensian climate and landscape in England: new data from Finningley, South Yorkshire2019In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, no 7, article id 190577Article in journal (Refereed)
    Abstract [en]

    While there is extensive evidence for the Late Devensian, less is known about Early and Middle Devensian (approx. 110-€“30 ka) climates and environments in the UK. The Greenland ice-core record suggests the UK should have endured multiple changes, but the terrestrial palaeo-record lacks sufficient detail for confirmation from sites in the British Isles. Data from deposits at Finningley, South Yorkshire, can help redress this. A channel with organic silts, dated 40 314-€“39 552 cal a BP, contained plant macrofossil and insect remains showing tundra with dwarf-shrub heath and bare ground. Soil moisture conditions varied from free draining to riparian, with ponds and wetter vegetated areas. The climate was probably low arctic with snow cover during the winter. Mutual climatic range (MCR), based on Coleoptera, shows the mean monthly winter temperatures of -ˆ’22 to -ˆ’2°C and summer ones of 8€-14°C. Periglacial structures within the basal gravel deposits and beyond the glacial limits indicate cold-climate conditions, including permafrost. A compilation of MCR reconstructions for other Middle Devensian English sites shows that marine isotope stage 3-€”between 59 and 28 ka-experienced substantial variation in climate consistent with the Greenland ice-core record. The exact correlation is hampered by temporal resolution, but the Finningley site stadial at approximately 40 ka may correlate with the one of the Greenland stadials 7-€“11.

  • Kufe, Nyuyki Clement
    et al.
    Masemola, Maphoko
    Chikowore, Tinashe
    Kengne, Andre Pascal
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Goedecke, Julia H.
    Micklesfield, Lisa K.
    Protocol for systematic review and meta-analysis of sex hormones and diabetes risk in ageing men and women of African ancestry2019In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 9, no 1, article id e024446Article, review/survey (Refereed)
    Abstract [en]

    Aim: To present the protocol of a systematic review and meta-analysis of the available evidence examining the association between sex hormones and type 2 diabetes risk in ageing men and women of African descent.

    Methods: We shall conduct a comprehensive search of published studies that examined the association between sex hormones and type 2 diabetes risk in men and women aged ≥40 years from 01/01/1980 to 31/03/2018 with no language restriction. Databases to be searched include: PubMed, Scopus, Cochrane Library, Cumulative Index to Nursing and Allied Health, ISI Web of Science, Clinical Trial registries, Google Scholar and institutional websites such as the WHO, American Diabetes Association, International Diabetes Federation, World Diabetes Foundation, European Association for the Study of Diabetes, African Journal Online and ProQuest databases. This protocol is developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. Independent screening for eligible studies using defined criteria and data extraction, will be completed in duplicate. Discrepancies will be resolved by consensus or consultation with a third researcher. Risk of bias of included studies will be assessed by the appropriate Cochrane risk of bias tool. The overall association estimates will be pooled using appropriate meta-analytic techniques. Heterogeneity will be assessed using Cochrane Q statistic and the inconsistency index (I2). The random effects model will be used to calculate a pooled estimate.

    Ethics and dissemination: No ethics clearance is required as no primary data will be collected. The systematic review and meta-analysis are part of a PhD project at WITS University (Johannesburg, South Africa) and results will be presented at conferences and published in a peer-review journal. The results will guide future population specific interventions.