131 research outputs found

    Central Norwegian Snow Patch Archaeology: Patterns Past and Present

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    Over nearly a century, a large assemblage of archaeological artifacts has been collected from some high-lying snow patches in a number of mountain areas in central Norway. The regional collection now comprises 234 individual artifacts that include both organic and inorganic elements. Many of these are arrowheads, shafts, and other equipment from past hunting expeditions on alpine snow patches. This article outlines three different phases of artifact recovery in the region: Phase I (1914 – 43) began with the initial snow patch discovery and included large numbers of finds in the 1930s and early 1940s; Phase II (1944 – 2000) had relatively few discoveries; and Phase III (2001 – 11) included discovery of 17 new sites and a record number of 145 artifacts. Local reindeer hunters and hikers have recovered many of the artifacts. There are close links between reindeer hunting and snow patch surveying in the region. The majority of snow patch finds were recovered during the period from mid-August through mid-September. The collection can best be viewed as a cohesive long-term record of melting snow patches.Pendant près d’un siècle, un large assemblage d’artefacts archéologiques a été recueilli dans les névés en haute altitude de certaines régions montagneuses du centre de la Norvège. Cette collection comprend maintenant 234 artefacts individuels, composés d’éléments organiques et d’éléments inorganiques. Des pointes de flèches, des fûts de flèches et d’autre matériel provenant d’anciennes expéditions de chasse dans les névés alpins s’y trouvent en grand nombre. Cet article présente les trois phases de la récupération d’artefacts dans la région, soit la phase I (de 1914 à 1943) qui a commencé avec la découverte du névé et a donné lieu à de nombreuses découvertes dans les années 1930 et au début des années 1940, la phase II (de 1944 à 2000) qui s’est soldée par relativement peu de découvertes, et la phase III (de 2001 à 2011) qui a permis de découvrir 17 nouveaux sites et le nombre record de 145 artefacts. Grand nombre des artefacts ont été récupérés par les chasseurs de rennes et les randonneurs pédestres de la région. Il existe des liens étroits entre la chasse aux rennes et la couverture des névés de la région. La majorité des découvertes effectuées dans les névés a été faite de la mi-août à la mi-septembre. Cette collection représente un enregistrement cohésif et à long terme des névés en fusion

    Unsupervised hyperspectral data mining and bioimaging by information entropy and self-modeling curve resolution

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    Unsupervised estimation of the dimensionality of hyperspectral microspectroscopy datasets containing pure and mixed spectral features, and extraction of their representative endmember spectra, remains a challenge in biochemical data mining. We report a new versatile algorithm building on semi-nonnegativity constrained self-modeling curve resolution and information entropy, to estimate the quantity of separable biochemical species from hyperspectral microspectroscopy, and extraction of their representative spectra. The algorithm is benchmarked with established methods from satellite remote sensing, spectral unmixing, and clustering. To demonstrate the widespread applicability of the developed algorithm, we collected hyperspectral datasets using spontaneous Raman, Coherent Anti-stokes Raman Scattering and Fourier Transform IR, of seven reference compounds, an oil-in-water emulsion, and tissue-engineered extracellular matrices on poly-L-lactic acid and porcine jejunum-derived small intestine submucosa scaffolds seeded with bovine chondrocytes. We show the potential of the developed algorithm by consolidating hyperspectral molecular information with sample microstructure, pertinent to fields ranging from gastrophysics to regenerative medicine

    The chronology of reindeer hunting on Norway's highest ice patches.

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    The melting of perennial ice patches globally is uncovering a fragile record of alpine activity, especially hunting and the use of mountain passes. When rescued by systematic fieldwork (glacial archaeology), this evidence opens an unprecedented window on the chronology of high-elevation activity. Recent research in Jotunheimen and surrounding mountain areas of Norway has recovered over 2000 finds-many associated with reindeer hunting (e.g. arrows). We report the radiocarbon dates of 153 objects and use a kernel density estimation (KDE) method to determine the distribution of dated events from ca 4000 BCE to the present. Interpreted in light of shifting environmental, preservation and socio-economic factors, these new data show counterintuitive trends in the intensity of reindeer hunting and other high-elevation activity. Cold temperatures may sometimes have kept humans from Norway's highest elevations, as expected based on accessibility, exposure and reindeer distributions. In times of increasing demand for mountain resources, however, activity probably continued in the face of adverse or variable climatic conditions. The use of KDE modelling makes it possible to observe this patterning without the spurious effects of noise introduced by the discrete nature of the finds and the radiocarbon calibration process

    Selective expansion of viral variants following experimental transmission of a reconstituted feline immunodeficiency virus quasispecies

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    Following long-term infection with virus derived from the pathogenic GL8 molecular clone of feline immunodeficiency virus (FIV), a range of viral variants emerged with distinct modes of interaction with the viral receptors CD134 and CXCR4, and sensitivities to neutralizing antibodies. In order to assess whether this viral diversity would be maintained following subsequent transmission, a synthetic quasispecies was reconstituted comprising molecular clones bearing envs from six viral variants and its replicative capacity compared in vivo with a clonal preparation of the parent virus. Infection with either clonal (Group 1) or diverse (Group 2) challenge viruses, resulted in a reduction in CD4+ lymphocytes and an increase in CD8+ lymphocytes. Proviral loads were similar in both study groups, peaking by 10 weeks post-infection, a higher plateau (set-point) being achieved and maintained in study Group 1. Marked differences in the ability of individual viral variants to replicate were noted in Group 2; those most similar to GL8 achieved higher viral loads while variants such as the chimaeras bearing the B14 and B28 Envs grew less well. The defective replication of these variants was not due to suppression by the humoral immune response as virus neutralising antibodies were not elicited within the study period. Similarly, although potent cellular immune responses were detected against determinants in Env, no qualitative differences were revealed between animals infected with either the clonal or the diverse inocula. However, in vitro studies indicated that the reduced replicative capacity of variants B14 and B28 in vivo was associated with altered interactions between the viruses and the viral receptor and co-receptor. The data suggest that viral variants with GL8-like characteristics have an early, replicative advantage and should provide the focus for future vaccine development

    Modulation of the virus-receptor interaction by mutations in the V5 loop of feline immunodeficiency virus (FIV) following in vivo escape from neutralising antibody

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    <b>BACKGROUND:</b> In the acute phase of infection with feline immunodeficiency virus (FIV), the virus targets activated CD4+ T cells by utilising CD134 (OX40) as a primary attachment receptor and CXCR4 as a co-receptor. The nature of the virus-receptor interaction varies between isolates; strains such as GL8 and CPGammer recognise a "complex" determinant on CD134 formed by cysteine-rich domains (CRDs) 1 and 2 of the molecule while strains such as PPR and B2542 require a more "simple" determinant comprising CRD1 only for infection. These differences in receptor recognition manifest as variations in sensitivity to receptor antagonists. In this study, we ask whether the nature of the virus-receptor interaction evolves in vivo.<p></p> <b>RESULTS:</b> Following infection with a homogeneous viral population derived from a pathogenic molecular clone, a quasispecies emerged comprising variants with distinct sensitivities to neutralising antibody and displaying evidence of conversion from a "complex" to a "simple" interaction with CD134. Escape from neutralising antibody was mediated primarily by length and sequence polymorphisms in the V5 region of Env, and these alterations in V5 modulated the virus-receptor interaction as indicated by altered sensitivities to antagonism by both anti-CD134 antibody and soluble CD134.<p></p> <b>CONCLUSIONS:</b> The FIV-receptor interaction evolves under the selective pressure of the host humoral immune response, and the V5 loop contributes to the virus-receptor interaction. Our data are consistent with a model whereby viruses with distinct biological properties are present in early versus late infection and with a shift from a "complex" to a "simple" interaction with CD134 with time post-infection.<p></p&gt

    Recent Progress In The Diagnosis And Treatment Of Multiple Sclerosis

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    Magnetic resonance imaging (MRI) now provides valuable diagnostic and prognostic information for the management of multiple sclerosis (MS) but the diagnosis still largely rests on the clinical features of central nervous system (CNS) lesions disseminated in time and place. Recent histological and MRI studies indicate that extensive axonal damage can occur in MS, even early in the disease course, and is likely to be an important cause of accumulating disability. Several immunomodulating agents have now been shown to have beneficial effects in MS. High dose intravenous or high dose oral methylprednisolone therapy accelerates recovery from attacks of relapsing-remitting MS, but at present there is no convincing evidence that standard dose (intermediate dose) oral corticosteroid therapy is beneficial for such attacks. Interferon beta, copolymer 1 (glatiramer acetate) and i.v. immunoglobulin therapy each significantly reduce the frequency of attacks of relapsing-remitting MS. Interferon beta also inhibits the progression of disability in relapsing-remitting MS and secondary progressive MS, but its effect on primary progressive MS is unknown. Oral low dose methotrexate therapy slows the progression of disability in secondary progressive MS and possibly in primary progressive MS, but it is likely that the currently used dosage (7.5 mg weekly) is suboptimal. Further research is needed to determine the optimal doses and combinations of the above therapies in MS and to develop better therapies, particularly for primary progressive MS

    BlackCAT: A catalogue of stellar-mass black holes in X-ray transients

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    During the last ~50 years, the population of black hole candidates in X-ray binaries has increased considerably with 59 Galactic objects detected in transient low-mass X-ray binaries, plus a few in persistent systems (including ~5 extragalactic binaries). We collect near-infrared, optical and X-ray information spread over hundreds of references in order to study the population of black holes in X-ray transients as a whole. We present the most updated catalogue of black hole transients, which contains X-ray, optical and near-infrared observations together with their astrometric and dynamical properties. It provides new useful information in both statistical and observational parameters providing a thorough and complete overview of the black hole population in the Milky Way. Analysing the distances and spatial distribution of the observed systems, we estimate a total population of ~1300 Galactic black hole transients. This means that we have already discovered less than ~5% of the total Galactic distribution. The complete version of this catalogue will be continuously updated online and in the Virtual Observatory, including finding charts and data in other wavelengths.Comment: http://www.astro.puc.cl/BlackCAT - Accepted for publication in Astronomy & Astrophysics. 20 pages, 8 figures, 5 Table

    Action 3:30R: Process evaluation of a cluster randomised feasibility study of a revised teaching assistant-led extracurricular physical activity intervention for 8 to 10 year olds

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    Background: Numerous interventions to increase children's physical activity levels are published, yet, few studies report indicators of external validity. Process evaluations are critical for assessing intervention implementation, sustainability and effectiveness. A mixed-methods process evaluation, using the RE-AIM framework, was conducted to evaluate the internal and external validity of Action 3:30R, a revised teaching assistant-led after-school intervention which aimed to increase physical activity in children aged 8-10 years and was underpinned by Self-determination Theory (SDT). Methods: Data were collected and reported in line with the five components of RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance). Quantitative measures included logbooks, registers and self-reported teaching-efficacy, autonomy support, child enjoyment and perceived exertion questionnaires. Questionnaire data were collected at three points throughout the 15-week intervention. Observations by trained researchers were also conducted to assess fidelity to the intervention manual and its underpinning theory. Post-intervention focus groups with pupils and interviews with teaching assistants (TAs), school staff and external stakeholders explored the implementation and potential sustainability of Action 3:30R from stakeholders' perspectives. Results: Action 3:30R appealed to a broad range of pupils, including girls and less-active pupils. The Action 3:30R TA training was implemented as intended and was perceived as valuable professional development. Releasing staff for training was a barrier in two of the six intervention schools, which were unable to deliver the intervention as a result. Pupils enjoyed the intervention, and the Action 3:30R core principles underpinned by SDT were implemented with high fidelity, as was the intervention itself. Scheduling conflicts with other clubs and lack of parental support were perceived as the main barriers to recruitment and attendance. Lack of space and season were cited as the main barriers affecting the quality of delivery. The study shows evidence of maintenance, as one intervention school decided to continue Action 3:30R beyond the study. Funding and continued TA training were suggested as factors which may affect the maintenance of Action 3:30R. Conclusions: Action 3:30R is an enjoyable, autonomy-supportive after-school programme, which engages a range of pupils and offers TAs valuable training. RE-AIM provided helpful structure and is recommended for intervention evaluations. Trial registration: ISRCTN34001941. Prospectively registered 01/12/2016
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