2,203 research outputs found

    An ideal solution? Optimising pretreatment methods for artificially mummified ancient Egyptian tissues

    Get PDF
    RATIONALE Although the analysis of skeletal remains dominates the study of ancient dietary stable isotopes, mummified bodies also allow short‐term diet to be studied through the analysis of soft tissues. The application of resins, waxes and oils during mummification can affect the results obtained. This study assesses a range of methods for removing such substances from mummified tissue. METHODS An experimental mummification model following ancient Egyptian methods was created using a modern pig leg. Sub‐samples of skin, muscle and bone were removed and coated with a range of substances used in Egyptian mummification. Four methods were used to clean these samples before the measurement of the carbon and nitrogen stable isotope ratios of their gelatinised collagen content using a ThermoFinnigan Flash Elemental analyser coupled to a DeltaPlus XL isotope ratio mass spectrometer via a ConFlo III interface. RESULTS The results showed that embalming materials can significantly affect dietary stable isotope ratios, and that these substances are most effectively removed using a mixture of polar and non‐polar solvents. Results indicate that bone samples demineralised with HCl and skin samples produce more accurate results than bone samples demineralised with EDTA or muscle samples. CONCLUSIONS The choice of tissue and the preparation methods used can have a significant effect on the accuracy of stable isotope data obtained from mummified tissue, particularly when embalming materials are also present. A mixture of solvents appears to be a more effective cleaning agent than a single solvent. Demineralisation with HCl is preferable for well‐preserved bone as used in this study, but whether this is the case for more fragile, less well‐preserved bone requires further study. Skin samples produce more consistent data than muscle, but visually distinguishing between these tissues is not simple on ancient mummies

    Walking as a meaningful leisure occupation: the implications for occupational therapy

    Get PDF
    Introduction: In response to growing interest in leisure in occupational therapy and the importance of understanding how occupations maintain, enhance and promote health and wellbeing, a qualitative phenomenological study was conducted to explore the experiences of walking for leisure. Method: Six healthy student participants, identified as regular walkers, were interviewed using a semi-structured format. Data were analysed following interpretative phenomenological analysis methodology. Findings: Participants expressed how and why walking was meaningful to them; the four main themes were social connectedness, wellbeing, connection to nature and achievement from a challenge. Findings suggest that occupational therapists could use walking and leisure occupations in intervention, and that there is scope for an occupational therapy perspective in health promotion. Conclusion: Determining the subjective meaning of engaging in walking as a leisure occupation has implications for occupational science and health promotion in helping to explain why people do what they do

    Exploring alternative symmetry breaking mechanisms at the LHC with 7, 8 and 10 TeV total energy

    Get PDF
    In view of the annnouncement that in 2012 the LHC will run at 8 TeV, we study the possibility of detecting signals of alternative mechanisms of ElectroWeak Symmetry Breaking, described phenomenologically by unitarized models, at energies lower than 14 TeV. A complete calculation with six fermions in the final state is performed using the PHANTOM event generator. Our results indicate that at 8 TeV some of the scenarios with TeV scale resonances are likely to be identified while models with no resonances or with very heavy ones will be inaccessible, unless the available luminosity will be much higher than expected

    Effective Theory of a Dynamically Broken Electroweak Standard Model at NLO

    Full text link
    We consider the Standard Model as an effective theory at the weak scale vv of a generic new strong interaction that dynamically breaks electroweak symmetry at the energy scale Λ∌\Lambda\sim (few) TeV. Assuming only the minimal field content with the Standard Model fermions and gauge bosons, but without a light Higgs particle, we construct the complete Lagrangian through next-to-leading order, that is, including terms of order v2/Λ2v^2/\Lambda^2. The systematics behind this expansion is clarified. Although similar to chiral perturbation theory, it is not governed by the dimension of operators alone, but depends in an essential way on the loop expansion. Power-counting formulas are derived that indicate the classes of operators required at the next-to-leading order. The complete set of operators at leading and next-to-leading order is then listed, based on the restrictions implied by the Standard-Model gauge symmetries. We recover the well-known operators discussed in the literature in connection with the electroweak chiral Lagrangian and in similar contexts, but we collect a complete and systematic list of all terms through order v2/Λ2v^2/\Lambda^2. This includes some operators not discussed in explicit terms before. We also show that a few of the previously considered operators can be eliminated via the equations of motion. As another important result we confirm the known list of dimension-6 operators in the Standard Model with an elementary Higgs doublet, essentially as a special case of our scenario.Comment: 35 pages, 1 figure; references adde

    Subanesthetic ketamine treatment promotes abnormal interactions between neural subsystems and alters the properties of functional brain networks

    Get PDF
    Acute treatment with subanesthetic ketamine, a non-competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist, is widely utilized as a translational model for schizophrenia. However, how acute NMDA receptor blockade impacts on brain functioning at a systems level, to elicit translationally relevant symptomatology and behavioral deficits, has not yet been determined. Here, for the first time, we apply established and recently validated topological measures from network science to brain imaging data gained from ketamine-treated mice to elucidate how acute NMDA receptor blockade impacts on the properties of functional brain networks. We show that the effects of acute ketamine treatment on the global properties of these networks are divergent from those widely reported in schizophrenia. Where acute NMDA receptor blockade promotes hyperconnectivity in functional brain networks, pronounced dysconnectivity is found in schizophrenia. We also show that acute ketamine treatment increases the connectivity and importance of prefrontal and thalamic brain regions in brain networks, a finding also divergent to alterations seen in schizophrenia. In addition, we characterize how ketamine impacts on bipartite functional interactions between neural subsystems. A key feature includes the enhancement of prefrontal cortex (PFC)-neuromodulatory subsystem connectivity in ketamine-treated animals, a finding consistent with the known effects of ketamine on PFC neurotransmitter levels. Overall, our data suggest that, at a systems level, acute ketamine-induced alterations in brain network connectivity do not parallel those seen in chronic schizophrenia. Hence, the mechanisms through which acute ketamine treatment induces translationally relevant symptomatology may differ from those in chronic schizophrenia. Future effort should therefore be dedicated to resolve the conflicting observations between this putative translational model and schizophrenia

    Things change: Women’s and men’s marital disruption dynamics in Italy during a time of social transformations, 1970-2003

    Get PDF
    We study women’s and men’s marital disruption in Italy between 1970 and 2003. By applying an event-history analysis to the 2003 Italian variant of the Generations and Gender Survey we found that the spread of marital disruption started among middle-highly educated women. Then in recent years it appears that less educated women have also been able to dissolve their unhappy unions. Overall we can see the beginning of a reversed educational gradient from positive to negative. In contrast the trend in men’s marital disruption risk appears as a change over time common to all educational groups, although with persisting educational differentials.determinants, educational differences, event history analysis, gender difference, Italy, marital disruption

    Ipl1/aurora kinase suppresses S-CDK-driven spindle formation during prophase I to ensure chromosome integrity during meiosis

    Get PDF
    Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK) during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics

    Studies of the transmissibility of the agent of bovine spongiform encephalopathy to the domestic chicken

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Transmission of the prion disease bovine spongiform encephalopathy (BSE) occurred accidentally to cattle and several other mammalian species via feed supplemented with meat and bone meal contaminated with infected bovine tissue. Prior to United Kingdom controls in 1996 on the feeding of mammalian meat and bone meal to farmed animals, the domestic chicken was potentially exposed to feed contaminated with the causal agent of BSE. Although confirmed prion diseases are unrecorded in avian species a study was undertaken to transmit BSE to the domestic chicken by parenteral and oral inoculations. Transmissibility was assessed by clinical monitoring, histopathological examinations, detection of a putative disease form of an avian prion protein (PrP) in recipient tissues and by mouse bioassay of tissues. Occurrence of a progressive neurological syndrome in the primary transmission study was investigated by sub-passage experiments.</p> <p>Results</p> <p>No clinical, pathological or bioassay evidence of transmission of BSE to the chicken was obtained in the primary or sub-passage experiments. Survival data showed no significant differences between control and treatment groups. Neurological signs observed, not previously described in the domestic chicken, were not associated with significant pathology. The diagnostic techniques applied failed to detect a disease associated form of PrP.</p> <p>Conclusion</p> <p>Important from a risk assessment perspective, the present study has established that the domestic chicken does not develop a prion disease after large parenteral exposures to the BSE agent or after oral exposures equivalent to previous exposures via commercial diets. Future investigations into the potential susceptibility of avian species to mammalian prion diseases require species-specific immunochemical techniques and more refined experimental models.</p
    • 

    corecore