3,411 research outputs found

    Phonons in potassium doped graphene: the effects of electron-phonon interactions, dimensionality and ad-atom ordering

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    Graphene phonons are measured as a function of electron doping via the addition of potassium adatoms. In the low doping regime, the in-plane carbon G-peak hardens and narrows with increasing doping, analogous to the trend seen in graphene doped via the field-effect. At high dopings, beyond those accessible by the field-effect, the G-peak strongly softens and broadens. This is interpreted as a dynamic, non-adiabatic renormalization of the phonon self-energy. At dopings between the light and heavily doped regimes, we find a robust inhomogeneous phase where the potassium coverage is segregated into regions of high and low density. The phonon energies, linewidths and tunability are remarkably similar for 1-4 layer graphene, but significantly different to doped bulk graphite.Comment: Accepted in Phys. Rev. B as a Rapid Communication. 5 pages, 3 figures, revised text with additional dat

    KinOath: Kinship software beta stage of development

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    KinOath is a kinship and archive retrieval application under development by Peter Withers at the Language Archive of the Max Planck Institute for Psycholinguistics Nijmegen. It is designed to be flexible and culturally nonspecific, such that culturally different social structures can equally be represented. By linking archived data to kinship individuals, queries can be performed to retrieve the archive data based on kinship relations. A lot of work has been done on the application since the last talk was given and many of the proposed features are now useable. Some of the recent features are; multiple diagram types such as freeform or kin term etc., matrimonial ring diagrams from kin type strings, customisable kin types, export to R or SPSS, customisable metadata via the Clarin Component Registry and ISOCat, improved kin type string database queries and browse-able kin trees. This talk will give a fresh introduction to the application and discuss the features that have become recently available

    Frinex: Framework for Interactive Experiments

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    Internal stresses in steel plate generated by shape memory alloy inserts

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    Neutron strain scanning was employed to investigate the internal stress fields in steel plate coupons with embedded prestrained superelastic NiTi shape memory alloy inserts. Strain fields in steel were evaluated at T = 21 °C and 130 °C on virgin coupons as well as on mechanically and thermally fatigued coupons. Internal stress fields were evaluated by direct calculation of principal stress components from the experimentally measured lattice strains as well as by employing an inverse finite element modeling approach. It is shown that if the NiTi inserts are embedded into the elastic steel matrix following a carefully designed technological procedure, the internal stress fields vary with temperature in a reproducible and predictable way. It is estimated that this mechanism of internal stress generation can be safely applied in the temperature range from −20 °C to 150 °C and is relatively resistant to thermal and mechanical fatigue. The predictability and fatigue endurance of the mechanism are of essential importance for the development of future smart metal matrix composites or smart structures with embedded shape memory alloy components

    Effect of Sampling Regime on Estimation of Basal Metabolic Rate and Standard Evaporative Water Loss Using Flow-Through Respirometry

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    Strict criteria have been established for measurement of basal metabolic rate and standard evaporative water loss to ensure that data can be compared intra‐ and interspecifically. However, data‐sampling regimes vary, from essentially continuous sampling to interrupted (switching) systems with data recorded periodically at more widely spaced intervals. Here we compare one continuous and three interrupted sampling regimes to determine whether sampling regime has a significant effect on estimation of basal metabolic rate or standard evaporative water loss. Compared to continuous 20‐s sampling averaged over 20 min, sampling every 6 min and averaging over 60 min overestimated basal metabolic rate and evaporative water loss, sampling every 3 min and averaging over 21 min underestimated basal metabolic rate, and sampling every 12 min and averaging over 36 min showed no difference in estimates. Increasing the period over which the minimum mean was calculated significantly increased estimates of physiological variables. Reducing the frequency of sampling from 20 s to a longer interval of 3, 6, or 12 min underestimated basal metabolic rate but not evaporative water loss. This indicates that sampling frequency per se influences estimates of basal metabolic rate and that differences are not just an artifact of differences in the period over which the mean is calculated. Sampling regime can have a highly significant influence on estimation of standard physiological variables, although the actual differences between sampling regimes were generally small (usually <5%). Although continuous sampling is the preferred sampling regime for open‐flow respirometry studies, if time and cost are prohibitive, then use of an appropriate switching system will result in smaller errors than measuring individuals continuously for shorter periods

    Does season or captivity influence the physiology of an endangered marsupial, the numbat (Myrmecobius fasciatus)?

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    We examined the effects of season and captivity on several commonly measured physiological variables (body temperature, metabolic rate, thermal conductance, and evaporative water loss [EWL]) for the numbat (Myrmecobius fasciatus), an endangered myrmecophagous Australian marsupial, because the maintenance of a wild-type physiology may increase the likelihood of successful reintroduction of numbats into the wild. Our results indicate that the physiology of male captive numbats is representative of wild individuals, at least at thermoneutrality, except for some diet-related effects on substrate metabolism and thermoregulation. Season significantly influenced physiological variables, in particular basal metabolic rate (BMR) and EWL. BMR was 30–37% higher in winter than in summer, and EWL increased at a high ambient temperature (Ta) in winter, presumably reflecting seasonal differences in Ta, food availability, and water consumption. Seasonal variation in physiological responses of captive numbats was similar to that observed for wild numbats. We conclude that there is seasonal flexibility in the physiology of numbats, and that captivity under seminatural conditions does not compromise their basic physiology
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