Which effective viscosity?

Magmas undergoing shear are prime examples of flows that involve the transport of solids and gases by a separate (silicate melt) carrier phase. Such flows are called multiphase, and have attracted much attention due to their important range of engineering applications. Where the volume fraction of the dispersed phase (crystals) is large, the influence of particles on the fluid motion becomes significant and must be taken into account in any explanation of the bulk behaviour of the mixture. For congested magma deforming well in excess of the dilute limit (particle concentrations >40% by volume), sudden changes in the effective or relative viscosity can be expected. The picture is complicated further by the fact that the melt phase is temperature- and shear-rate-dependent. In the absence of a constitutive law for the flow of congested magma under an applied force, it is far from clear which of the many hundreds of empirical formulae devised to predict the rheology of suspensions as the particle fraction increases with time are best suited. Some of the more commonly used expressions in geology and engineering are reviewed with an aim to home in on those variables key to an improved understanding of magma rheology. These include a temperature, compositional and shear-rate dependency of viscosity of the melt phase with the shear-rate dependency of the crystal (particle) packing arrangement. Building on previous formulations, a new expression for the effective (relative) viscosity of magma is proposed that gives users the option to define a packing fraction range as a function of shear stress. Comparison is drawn between processes (segregation, clustering, jamming), common in industrial slurries, and structures seen preserved in igneous rocks. An equivalence is made such that congested magma, viewed in purely mechanical terms as a high-temperature slurry, is an inherently non-equilibrium material where flow at large Péclet numbers may result in shear thinning and spontaneous development of layering

Allometric scaling of thermal infrared emitted from UK cities and its relation to urban form

As a result of differences in heat absorption and release between urban and rural landscapes, cities develop a climate different from their surroundings. The rise in global average surface temperature and high rates of urbanization, make it important to understand the energy balance of cities, including whether any energy-balance-related patterns emerge as a function of city size. In this study, images from the Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite instrument, covering the period between 2000 and 2017, were sampled to examine the seasonal (winter and summer) night-time clear-sky upwelling long-wave energy for 35 UK cities. Total (area-summed) emitted energy per overpass per city is shown to correlate closely (R2 ≥ 0.79) with population on a log-log ‘allometry’ plot. The production of emitted energy from the larger cities is smaller than would be produced from a constellation of smaller cities housing the same population. The mean allometry slope over all overpasses sampled is 0.84±0.06, implying an ‘economy (or parsimony) of scale’ (i.e., a less-than-proportional increase) of about 21% (i.e. 100(2-100.84log(2))) for each doubling of city population. City area shows a very similar economy of scale, so that the scaling of night-time emitted energy with urban area is close to linear (1.0±0.05). This linearity with area indicates that the urban forms used in UK cities to accommodate people more efficiently per unit area as the urban population grows, do not have a large effect on the thermal output per unit area in each city. Although often appearing superficially very different, UK cities appear to be similar in terms of the components of urban form that dictate thermal properties. The difference between the scaling of the heat source and literature reports of the scaling of urban-rural air (or surface) temperature difference is very marked, suggesting that the other factors affecting the temperature difference act to decrease strongly its scaling with population

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

Behandeling en stigmamanagement bij opzettelijke zelfverwonding: het smalle pad tussen te veel en te weinig interveniëren

Opzettelijke zelfverwonding wordt gedefinieerd als de intentionele directe beschadiging van het eigen lichaam, zonder bewuste suïcidale intentie. De behandeling varieert van gedwongen opname in een psychiatrische instelling (in het Britse Gemenebest), tot een permissieve aanpak zonder behandeling en uiteenlopende behandelingsmogelijkheden er tussenin. Eerst wordt de gepastheid van de mate van interveniëren besproken in functie van verschillende diagnosen. Het tweede gedeelte van het artikel bespreekt het advies dat door hulpverleners verstrekt wordt aangaande de omgang met wonden en littekens en aangaande de mogelijkheden voor een (gewezen) zelfverwonder om het stigma van een deviante identiteit te vermijden. Een rondvraag bij Belgische hulpverleners bracht aan het licht dat velen onder hen adviseren om littekens te verbergen, terwijl er anderzijds aanwijzingen zijn dat niet-verbergen een teken van herstel is. Aangezien verbergen en smoesjes verzinnen ook kunnen leiden tot de instandhouding van een deviante identiteit, wordt gewezen op meer gepaste vormen van stigmamanagement

Environment-Induced Decoherence and the Transition From Quantum to Classical

We study dynamics of quantum open systems, paying special attention to those aspects of their evolution which are relevant to the transition from quantum to classical. We begin with a discussion of the conditional dynamics of simple systems. The resulting models are straightforward but suffice to illustrate basic physical ideas behind quantum measurements and decoherence. To discuss decoherence and environment-induced superselection einselection in a more general setting, we sketch perturbative as well as exact derivations of several master equations valid for various systems. Using these equations we study einselection employing the general strategy of the predictability sieve. Assumptions that are usually made in the discussion of decoherence are critically reexamined along with the ``standard lore'' to which they lead. Restoration of quantum-classical correspondence in systems that are classically chaotic is discussed. The dynamical second law -it is shown- can be traced to the same phenomena that allow for the restoration of the correspondence principle in decohering chaotic systems (where it is otherwise lost on a very short time-scale). Quantum error correction is discussed as an example of an anti-decoherence strategy. Implications of decoherence and einselection for the interpretation of quantum theory are briefly pointed out.Comment: 80 pages, 7 figures included, Lectures given by both authors at the 72nd Les Houches Summer School on "Coherent Matter Waves", July-August 199

Linear polarization structures in LOFAR observations of the interstellar medium in the 3C 196 field

This study aims to characterize linear polarization structures in LOFAR observations of the interstellar medium (ISM) in the 3C196 field, one of the primary fields of the LOFAR-Epoch of Reionization key science project. We have used the high band antennas (HBA) of LOFAR to image this region and Rotation Measure (RM) synthesis to unravel the distribution of polarized structures in Faraday depth. The brightness temperature of the detected Galactic emission is 5−15 K in polarized intensity and covers the range from -3 to +8 rad m−2 in Faraday depth. The most interesting morphological feature is a strikingly straight filament at a Faraday depth of +0.5 rad m−2 running from north to south, right through the centre of the field and parallel to the Galactic plane. There is also an interesting system of linear depolarization canals conspicuous in an image showing the peaks of Faraday spectra. We used the Westerbork Synthesis Radio Telescope (WSRT) at 350 MHz to image the same region. For the first time, we see some common morphology in the RM cubes made at 150 and 350~{; ; \rm MHz}; ; . There is no indication of diffuse emission in total intensity in the interferometric data, in line with results at higher frequencies and previous LOFAR observations. Based on our results, we determined physical parameters of the ISM and proposed a simple model that may explain the observed distribution of the intervening magneto- ionic medium. The mean line-of-sight magnetic field component, B∥, is determined to be 0.3±0.1 μG and its spatial variation across the 3C196 field is 0.1 μG. The filamentary structure is probably an ionized filament in the ISM, located somewhere within the Local Bubble. This filamentary structure shows an excess in thermal electron density (neB∥&gt;6.2 cm−3μG) compared to its surroundings

Expression of Lamin A/C in early-stage breast cancer and its prognostic value

Purpose: Lamins A/C, a major component of the nuclear lamina, plays key roles in maintaining nuclear integrity, regulation of gene expression, cell proliferation and apoptosis. Reduced lamin A/C expression in cancer has been reported to be a sign of poor prognosis. However, its clinical significance in breast cancer remains to be defined. This study aimed to evaluate expression and prognostic significance of lamin A/C in early-stage breast cancer.Methods: Using immunohistochemical staining of tissue microarrays, expression of lamin A/C was evaluated in a large well-characterised series of early-stage operable breast cancer (n=938) obtained from Nottingham Primary Breast Carcinoma Series. Association of lamin A/C expression with clinicopathological parameters and outcome was evaluated.Results: Positive expression rate of lamin A/C in breast cancer was 42.2% (n=398). Reduced/loss of expression of lamin A/C was significantly associated with high histological grade (p [less than] 0.001), larger tumour size (p=0.004), poor Nottingham Prognostic Index (NPI) score (p [less than] 0.001), lymphovascular invasion (p=0.014) and development of distant metastasis (p=0.027). Survival analysis showed that reduced/loss of expression of lamin A/C was significantly associated with shorter breast cancer specific survival (p=0.008).Conclusion: This study suggests lamin A/C plays a role in breast cancer and loss of its expression is associated with variables of poor prognosis and shorter outcome

Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review

Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

This paper constructs the reduction of heterotic $M$-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe