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- Barton, Nick, et al.
(författare)
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New insights into the late Middle Stone Age occupation of Oued elAkarit, southern Tunisia
- 2021
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Ingår i: Libyan Studies. - : Cambridge University Press. - 0263-7189 .- 2052-6148. ; 52, s. 12-35
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Tidskriftsartikel (refereegranskat)abstract
- This article reports on a new project to investigate the activities of early Homo sapiens in the area of the Chotts ‘megalake’ in southernTunisia. Excavations in 2015 and 2019 at Oued el Akarit revealed one of a number of Middle Stone Age (MSA) horizons near the topof a long sequence of Upper Pleistocene deposits. The site identified as Oued el Akarit (Sondage 8) consists of lithic artefacts, bone fragmentsof large ungulates and pieces of ostrich eggshell. Many of the objects are burnt. Excavation of about nine square metres revealed thatthese were associated with a lightly trampled and combusted occupation surface. Amongst the identified artefacts were Levallois flakes someof which could be refitted, thereby indicating the generally undisturbed nature of the occupation. The lithic finds also included side scrapersand other tools diagnostic of the MSA but significantly no bifacial or tanged tools. OSL (Optically Stimulated Luminescence) dating of thesediments and AMS (Accelerator Mass Spectrometry) radiocarbon dating of ostrich eggshell have produced uncalibrated age determinationsin the range 37,000–40,000 years ago, one of the youngest ages for MSA sites in the region. This is the first example of a securely dated laterMSA occupation in a riparian environment in south-eastern Tunisia
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- Craddock, Nick, et al.
(författare)
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Genome-wide association study of CNVs in 16,000 cases of eight common diseases and 3,000 shared controls
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7289, s. 713-720
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Tidskriftsartikel (refereegranskat)abstract
- Copy number variants (CNVs) account for a major proportion of human genetic polymorphism and have been predicted to have an important role in genetic susceptibility to common disease. To address this we undertook a large, direct genome-wide study of association between CNVs and eight common human diseases. Using a purpose-designed array we typed,19,000 individuals into distinct copy-number classes at 3,432 polymorphic CNVs, including an estimated similar to 50% of all common CNVs larger than 500 base pairs. We identified several biological artefacts that lead to false-positive associations, including systematic CNV differences between DNAs derived from blood and cell lines. Association testing and follow-up replication analyses confirmed three loci where CNVs were associated with disease-IRGM for Crohn's disease, HLA for Crohn's disease, rheumatoid arthritis and type 1 diabetes, and TSPAN8 for type 2 diabetes-although in each case the locus had previously been identified in single nucleotide polymorphism (SNP)-based studies, reflecting our observation that most common CNVs that are well-typed on our array are well tagged by SNPs and so have been indirectly explored through SNP studies. We conclude that common CNVs that can be typed on existing platforms are unlikely to contribute greatly to the genetic basis of common human diseases.
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- Dalen, Love, et al.
(författare)
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Identifying Bird Remains Using Ancient DNA Barcoding
- 2017
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- Bird remains that are difficult to identify taxonomically using morphological methods, are common in the palaeontological record. Other types of challenging avian material include artefacts and food items from endangered taxa, as well as remains from aircraft strikes. We here present a DNA-based method that enables taxonomic identification of bird remains, even from material where the DNA is heavily degraded. The method is based on the amplification and sequencing of two short variable parts of the 16S region in the mitochondrial genome. To demonstrate the applicability of this approach, we evaluated the method on a set of Holocene and Late Pleistocene postcranial bird bones from several palaeontological and archaeological sites in Europe with good success.
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- Hudson, Lawrence N, et al.
(författare)
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The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project
- 2017
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 7:1, s. 145-188
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Tidskriftsartikel (refereegranskat)abstract
- The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
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- Lagerholm, Vendela K., et al.
(författare)
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Range shifts or extinction? Ancient DNA and distribution modelling reveal past and future responses to climate warming in cold-adapted birds
- 2017
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23:4, s. 1425-1435
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Tidskriftsartikel (refereegranskat)abstract
- Global warming is predicted to cause substantial habitat rearrangements, with the most severe effects expected to occur in high-latitude biomes. However, one major uncertainty is whether species will be able to shift their ranges to keep pace with climate-driven environmental changes. Many recent studies on mammals have shown that past range contractions have been associated with local extinctions rather than survival by habitat tracking. Here, we have used an interdisciplinary approach that combines ancient DNA techniques, coalescent simulations and species distribution modelling, to investigate how two common cold-adapted bird species, willow and rock ptarmigan (Lagopus lagopus and Lagopus muta), respond to long-term climate warming. Contrary to previous findings in mammals, we demonstrate a genetic continuity in Europe over the last 20 millennia. Results from back-casted species distribution models suggest that this continuity may have been facilitated by uninterrupted habitat availability and potentially also the greater dispersal ability of birds. However, our predictions show that in the near future, some isolated regions will have little suitable habitat left, implying a future decrease in local populations at a scale unprecedented since the last glacial maximum.
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- Lei, Qinghua, et al.
(författare)
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On the selection of joint constitutive models for geomechanics simulation of fractured rocks
- 2022
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Ingår i: Computers and geotechnics. - : Elsevier. - 0266-352X .- 1873-7633. ; 145
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Tidskriftsartikel (refereegranskat)abstract
- Fractures such as faults and joints often dominate the mechanical strength and deformation of rock masses. It is thus of central importance to adopt an appropriate joint constitutive model in geomechanics simulations so that the behaviour of fractures can be realistically represented. Over the past decades, various joint constitutive models have been proposed from theoretical/experimental perspectives and implemented into different geomechanics solvers. However, numerical modelling researchers are often confronted and even confused with the question about which joint model to use in their simulations, especially when a compromise needs to be reached between the realism (or complexity) of the selected constitutive model and the difficulty in the numerical implementation. In this Short Communication, we review some of the popular joint constitutive laws that have been used for geomechanics simulations and present a discussion on their suitability and limitations, aiming to provide a guidance for the joint constitutive model selection for computer simulations. We also point out a few unrealistic features of some widely used joint constitutive models with corresponding corrections recommended.
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- Rabiniak, Emilia, et al.
(författare)
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Late Pleistocene and Holocene pikas (Mammalia, Lagomorpha) from Europe and the validity of Ochotona spelaea : New insights based on mtDNA analysis
- 2023
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Ingår i: Palaeontologia Electronica. - : Coquina Press. - 1935-3952 .- 1094-8074. ; 26:1
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Tidskriftsartikel (refereegranskat)abstract
- Pikas were among small mammals that inhabited mammoth steppes during the last glacial. The evolutionary history of ochotonids in Europe is relatively well studied, although the taxonomic status of many described forms remains ambiguous, and the majority of extant species of the genus Ochotona are poorly represented in the fossil record. The present study aims to analyse the taxonomic relationships of a sample of Late Pleistocene-Holocene pikas based on mtDNA data and to clarify the status of the species described from Europe. A phylogenetic analysis has revealed that pikas form two large clades: one includes O. pusilla and the other includes the extant Asian and North American species. The study of haplotypes has shown similar results. The analysis supports the view that in the Late Pleistocene and Holocene O. pusilla was distributed throughout Europe, and its geographic range has contracted to the east until reaching its modern limits. The analysis of samples provided evidence that O. pusilla had survived in Eastern Europe until relatively recently and disappeared only about 150 years ago. The molecular data inferred from mtDNA do not support the species status of O. spelaea, despite morphological differences possibly related to the particular ecology of the Late Pleistocene.
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