1,976 research outputs found

    Repo-Man-PP1:A link between chromatin remodelling and nuclear envelope reassembly

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    Coordination of late mitotic events is crucial for the maintenance of genome stability and for the control of gene expression after cell division. Reversible protein phosphorylation regulates this process by de-phosphorylation of mitotic phospho-proteins in a sequential and coordinated manner: this allows an orderly sequence of events to take place during mitotic exit. We have identified Repo-Man/PP1 as a phosphatase complex that regulates temporally and spatially chromatin re-organization and nuclear envelope re-formation during anaphase-telophase

    On the structure and spectrum of classical two-dimensional clusters with a logarithmic interaction potential

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    We present a numerical study of the effect of the repulsive logarithmic inter-particle interaction on the ground state configuration and the frequency spectrum of a confined classical two-dimensional cluster containing a finite number of particles. In the case of a hard wall confinement all particles form one ring situated at the boundary of the potential. For a general r^n confinement potential, also inner rings can form and we find that all frequencies lie below the frequency of a particular mode, namely the breathing-like mode. An interesting situation arises for the parabolic confined system(i.e. n=2). In this case the frequency of the breathing mode is independent of the number of particles leading to an upper bound for all frequencies. All results can be understood from Earnshaw's theorem in two dimensions. In order to check the sensitivity of these results, the spectrum of vortices in a type II superconductor which, in the limit of large penetration depths, interact through a logarithmic potential, is investigated.Comment: 11 pages, 6 figure

    I\u27ll Come Back To You

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    https://digitalcommons.library.umaine.edu/mmb-vp/2988/thumbnail.jp

    Performance of the Colorado wind-profiling network, part 1.5A

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    The Wave Propagation Laboratory (WPL) has operated a network of radar wind Profilers in Colorado for about 1 year. The network consists of four VHF (50-MHz) radars and a UHF (915-MHz) radar. The Platteville VHF radar was developed by the Aeronomy Laboratory (AL) and has been operated jointly by WPL and AL for several years. The other radars were installed between February and May 1983. Experiences with these radars and some general aspects of tropospheric wind measurements with Doppler radar are discussed

    A Black Hole Levitron

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    We study the problem of spatially stabilising four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes kept in external fields we find that taking a continuum limit of Denef et al's multi-center solutions provides a supergravity description of such backgrounds within which a black hole can be trapped in a given volume. This is realised by levitating a black hole over a magnetic dipole base. We comment on how such a construction resembles a mechanical Levitron.Comment: 5 pages, 1 figur

    The Flexible Modelling Framework for the Met Office Unified Model (Flex-UM, using UM 12.0 release)

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    This is the final version. Available on open access from the European Geosciences Union via the DOI in this recordCode and data availability: The UM code and its configuration files are subject to Crown Copyright. A licence for the UM can be requested from https://www.metoffice.gov.uk/research/approach/collaboration/unified-model/partnership (last access: 10 June 2021). The source code for Flex-UM will be available as a branch of the UM in version 12.0 and will be available at https://code.metoffice.gov.uk/trac/um/browser (last access: 5 February 2021) (to access this link, you first need to apply via the link above). The Flex-UM simulations in this study were completed using modifications to UM version 11.7, and the GA7.0 simulations were completed using version 11.6. The simplified Betts–Miller scheme and slab-ocean codes used in this study are already on the UM code trunk in version 11.7 as part of the Trac code management system (see link above). The grey radiation scheme, boundary layer code and large-scale precipitation are currently under review and will be made available as part of the next UM release (version 12.1). The configuration files used in this study are available at https://code.metoffice.gov.uk/trac/roses-u/browser (last access: 5 February 2021) for the following UM suite IDs: Flex-UM fixed-SST (u-cc036), Flex-UM slab ocean (u-cc037), GA7.0 fixed SST (u-cc038) and GA7.0 slab ocean (u-cc039). The model output for Flex-UM and GA7.0 can be downloaded at https://doi.org/10.5281/zenodo.5700372 (Maher, 2021a). The Flex-UM and GA7.0 data can also be downloaded directly from the Met Office archive using these suite IDs. The Isca model output can be downloaded at https://doi.org/10.5281/zenodo.5017471 (Maher, 2021b). The post-processing and Python scripts used in this paper can be downloaded at https://doi.org/10.5281/zenodo.5700633 (Maher, 2021c).The Met Office Unified Model (UM) is a world-leading atmospheric weather and climate model. In addition to comprehensive simulations of the atmosphere, the UM is capable of running idealised simulations, such as the dry physics Held–Suarez test case, radiative convective equilibrium and simulating planetary atmospheres other than Earth. However, there is a disconnect between the simplicity of the idealised UM model configurations and the full complexity of the UM. This gap inhibits the broad use of climate model hierarchy approaches within the UM. To fill this gap, we have developed the Flexible Modelling Framework for the UM – Flex-UM – which broadens the climate model hierarchy capabilities within the UM. Flex-UM was designed to replicate the atmospheric physics of the Geophysical Fluid Dynamics Laboratory (GFDL) idealised moist physics aqua-planet model. New parameterisations have been implemented in Flex-UM, including simplified schemes for convection, large-scale precipitation, radiation, boundary layer and sea surface temperature (SST) boundary conditions. These idealised parameterisations have been implemented in a modular way, so that each scheme is available for use in any model configuration. This has the advantage that we can incrementally add or remove complexity within the model hierarchy. We compare Flex-UM to ERA5 and aqua-planet simulations using the Isca climate modelling framework (based on the GFDL moist physics aqua-planet model) and comprehensive simulations of the UM (using the GA7.0 configuration). We also use two SST boundary conditions to compare the models (fixed SST and a slab ocean). We find the Flex-UM climatologies are similar to both Isca and GA7.0 (though Flex-UM is generally a little cooler, with higher relative humidity and a less pronounced storm track). Flex-UM has a single Intertropical Convergence Zone (ITCZ) in the slab-ocean simulation but a double-ITCZ in the fixed-SST simulation. Further work is needed to ensure that the atmospheric energy budget closes to within 1–2 W m−2, as the current configuration of Flex-UM gains 9–11 W m−2 (the range covers the two SST boundary conditions). Flex-UM greatly extends the modelling hierarchy capabilities of the UM and offers a simplified framework for developing, testing and evaluating parameterisations within the UM.Natural Environment Research Council (NERC

    Starting to smoke: a qualitative study of the experiences of Australian indigenous youth

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    BackgroundAdult smoking has its roots in adolescence. If individuals do not initiate smoking during this period it is unlikely they ever will. In high income countries, smoking rates among Indigenous youth are disproportionately high. However, despite a wealth of literature in other populations, there is less evidence on the determinants of smoking initiation among Indigenous youth. The aim of this study was to explore the determinants of smoking among Australian Indigenous young people with a particular emphasis on the social and cultural processes that underlie tobacco use patterns among this group. MethodsThis project was undertaken in northern Australia. We undertook group interviews with 65 participants and individual in-depth interviews with 11 youth aged 13–20 years led by trained youth ‘peer researchers.’ We also used visual methods (photo-elicitation) with individual interviewees to investigate the social context in which young people do or do not smoke. Included in the sample were a smaller number of non-Indigenous youth to explore any significant differences between ethnic groups in determinants of early smoking experiences. The theory of triadic influence, an ecological model of health behaviour, was used as an organising theory for analysis. ResultsFamily and peer influences play a central role in smoking uptake among Indigenous youth. Social influences to smoke are similar between Indigenous and non-Indigenous youth but are more pervasive (especially in the family domain) among Indigenous youth. While Indigenous youth report high levels of exposure to smoking role models and smoking socialisation practices among their family and social networks, this study provides some indication of a progressive denormalisation of smoking among some Indigenous youth. ConclusionsFuture initiatives aimed at preventing smoking uptake in this population need to focus on changing social normative beliefs around smoking, both at a population level and within young peoples’ immediate social environment. Such interventions could be effectively delivered in both the school and family environments. Specifically, health practitioners in contact with Indigenous families should be promoting smoke free homes and other anti-smoking socialisation behaviours

    A new, clean catalogue of extragalactic non-nuclear X-ray sources in nearby galaxies

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    We have created a new, clean catalogue of extragalactic non-nuclear X-ray sources by correlating the 3XMM-DR4 data release of the XMM-Newton Serendipitous Source Catalogue with the Third Reference Catalogue of Bright Galaxies and the Catalogue of Neighbouring Galaxies, using an improved version of the method presented in Walton et al. Our catalogue contains 1314 sources, of which 384 are candidate ultraluminous X-ray sources (ULXs). The resulting catalogue improves upon previous catalogues in its handling of spurious detections by taking into account XMM-Newton quality flags. We estimate the contamination of ULXs by background sources to be 24 per cent. We define a 'complete' subsample as those ULXs in galaxies for which the sensitivity limit is below 10 39 erg s -1 and use it to examine the hardness ratio properties between ULX and non-ULX sources, and ULXs in different classes of host galaxy. We find that ULXs have a similar hardness ratio distribution to lower luminosity sources, consistent with previous studies. We also find that ULXs in spiral and elliptical host galaxies have similar distributions to each other independent of host galaxy morphology, however, our results do support previous indications that the population of ULXs is more luminous in star-forming host galaxies than in non-star-forming galaxies. Our catalogue contains further interesting subpopulations for future study, including Eddington Threshold sources and highly variable ULXs. We also examine the highest luminosity (L X > 5 × 10 40 erg s -1) ULXs in our catalogue in search of intermediate-mass black hole candidates, and find nine new possible candidates.We gratefully acknowledge support from the Science and Technology Facilities Council (HPE through grant ST/K501979/1, TPR through ST/P000541/1). HPE acknowledges support under National Aeronautics and Space Administration contract NNG08FD60C. MJM and DJW acknowledge support from STFC Ernest Rutherford fellowships. SM acknowledges financial support by the Spanish Ministry of Economy and Competitiveness through grant AYA2016-76730-P (MINECO/FEDER)

    ChromatoShiny: an interactive R/Shiny App for plotting chromatography profiles [version 2; peer review: 2 approved]

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    BackgroundUnicorn™ software on Äkta liquid chromatography instruments outputs chromatography profiles of purified biological macromolecules. While the plots generated by the instrument software are very helpful to inspect basic chromatogram properties, they lack a range of useful annotation, customization and export options.MethodsWe use the R Shiny framework to build an interactive app that facilitates the interpretation of chromatograms and the generation of figures for publications.ResultsThe app allows users to fit a baseline, to highlight selected fractions and elution volumes inside or under the plot (e.g. those used for downstream biochemical/biophysical/structural analysis) and to zoom into the plot. The app is freely available at https://ChromatoShiny.bio.ed.ac.uk.ConclusionsIt requires no programming experience, so we anticipate that it will enable chromatography users to create informative, annotated chromatogram plots quickly and simply.FPLC instruments used to purify macromolecules output the UV intensity values over the elution volume. However, the software used with these instruments is not usually used to generate the figures for publication. To facilitate the analysis of chromatograms and generation of publication figures, we developed a web app which is possible to use without programming skills. The app is working on Äkta .txt files and is able to fit a baseline, to highlight fractions on and under the plot and to zoom into the plot. The app is designed for Äkta instruments, but the data from other softwares can be entered in the provided template and plotted accordingly. The app is well suited for plotting many similar plots. The plots can be downloaded in various formats. The app is equipped with instructions and has a user friendly interface. We hope that the app will become a helpful tool for displaying chromatograms from various FPLC softwares
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