2,778 research outputs found

    Invalid party wall awards and how to avoid them

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    Considers the reasons for the invalidity of party wall awards. Examines decided cases under earlier party wall legislation in the context of the Party Wall etc. Act 1996. Explains invalidity on the basis of an excess of the surveyors’ statutory authority. Defines this authority in terms of jurisdiction and power. Demonstrates the limits of the surveyors’ authority and emphasises the importance of strict compliance with statutory procedures. Concludes that surveyors should adopt an inquisitive and analytical approach to the scope of their authority to avoid the possibility of invalid awards. Echoes John Anstey’s earlier warning that surveyors should avoid a broad-brush approach to their duties which will only leave them “covered in soot”

    Lattice Kinetics of Diffusion-Limited Coalescence and Annihilation with Sources

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    We study the 1D kinetics of diffusion-limited coalescence and annihilation with back reactions and different kinds of particle input. By considering the changes in occupation and parity of a given interval, we derive sets of hierarchical equations from which exact expressions for the lattice coverage and the particle concentration can be obtained. We compare the mean-field approximation and the continuum approximation to the exact solutions and we discuss their regime of validity.Comment: 24 pages and 3 eps figures, Revtex, accepted for publication in J. Phys.

    Fire analysis of steel frames with the use of artificial neural networks

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    The paper presents an alternative approach to the modelling of the mechanical behaviour of steel frame material when exposed to the high temperatures expected in fires. Based on a series of stress-strain curves obtained experimentally for various temperature levels, an artificial neural network (ANN) is employed in the material modelling of steel. Geometrically and materially, a non-linear analysis of plane frame structures subjected to fire is performed by FEM. The numerical results of a simply supported beam are compared with our measurements, and show a good agreement, although the temperature-displacement curves exhibit rather irregular shapes. It can be concluded that ANN is an efficient tool for modelling the material properties of steel frames in fire engineering design studies. (c) 2007 Elsevier Ltd. All rights reserved

    Family Unification, Exotic States and Light Magnetic Monopoles

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    Models with fermions in bifundamental representations can lead naturally to family unification as opposed to family replication. Such models typically predict (exotic) color singlet states with fractional electric charge, and magnetic monopoles with multiple Dirac charge. The exotics may be at the TeV scale, and relatively light magnetic monopoles (greater than about 10^7 GeV) can be present in the galaxy with abundance near the Parker bound. We focus on three family SU(4)XSU(3)XSU(3) models.Comment: 37 page

    Coupling between magnon and ligand-field excitations in magnetoelectric Tb3Fe5O12 garnet

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    The spectra of far-infrared transmission in Tb3Fe5O12 magnetoelectric single crystals have been studied in the range between 15 and 100 cm-1, in magnetic fields up to 10 T, and for temperatures between 5 and 150 K. We attribute some of the observed infrared-active excitations to electric-dipole transitions between ligand-field split states of Tb3+ ions. Anticrossing between the magnetic exchange excitation and the ligand-field transition occurs at the temperature between 60 and 80 K. The corresponding coupling energy for this interaction is 6 cm-1. Temperature-induced softening of the hybrid IR excitation correlates with the increase of the static dielectric constant. We discuss the possibility for hybrid excitations of magnons and ligand-field states and their possible connection to the magnetoelectric effect in Tb3Fe5O12.Comment: submitted to Phys. Rev. B on May 15th, 201

    Lipidomic Profiling of Di- and Tri-Acylglycerol Species in Weight-Controlled Mice

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    Citation: King, B. S., Lu, L. Z., Yu, M., Jiang, Y., Standard, J., Su, X. Y., . . . Wang, W. Q. (2015). Lipidomic Profiling of Di- and Tri-Acylglycerol Species in Weight-Controlled Mice. Plos One, 10(2), 12. doi:10.1371/journal.pone.0116398Weight control by dietary calorie restriction (DCR) or exercise has been shown to prevent cancer in various models. However, the mechanisms as to how weight control is beneficial are not well understood. While previous reports have investigated the effects of weight control on total lipid levels or lipid composition within cellular membranes, there has been little work surrounding changes to individual lipids following weight control interventions. In this study, using a model of skin carcinogenesis centered on the tumor promotion stage, CD-1 mice were randomly assigned into 4 groups: ad libitum and sedentary (control), ad libitum with exercise (AL+Exe), exercise with pair feeding of a diet isocaloric with control (PF+Exe), and sedentary with 20% DCR compared to control. After ten weeks, body weight and body fat percentages significantly decreased in the PF+Exe and DCR groups but not AL+Exe when compared with sedentary controls. Murine skin and plasma samples were obtained for analysis. Lipidomics using electrospray ionization MS/MS was employed to profile triacylglycerol (TG) and diacylglycerol (DG) species. Both plasma and tissue TG species containing fatty acid chains with length 18: 1 were significantly decreased following DCR when compared to sedentary control animals. In regards to DG, the most significant changes occurred in the plasma. DG species containing fatty acids with lengths 16: 1 or 18: 1 were significantly decreased in PF+Exe and DCR groups when compared to sedentary controls. Due to the significant role of TG in energy storage and DG in cellular signaling, our findings of the effects of weight control on individual TG and DG species in plasma and skin tissue following exposure to a tumor promoter, may provide insight into the mechanism of weight control on cancer prevention

    Running Spectral Index and Formation of Primordial Black Hole in Single Field Inflation Models

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    A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of long-lived Primordial Black Holes (PBHs). To that end we calculate the spectral index of the power spectrum of primordial perturbations as well as its first and second derivatives. PBH formation is possible only if the spectral index increases significantly at small scales, i.e. large wave number kk. Since current data indicate that the first derivative αS\alpha_S of the spectral index nS(k0)n_S(k_0) is negative at the pivot scale k0k_0, PBH formation is only possible in the presence of a sizable and positive second derivative ("running of the running") βS\beta_S. Among the three small-field and five large-field models we analyze, only one small-field model, the "running mass" model, allows PBH formation, for a narrow range of parameters. We also note that none of the models we analyze can accord for a large and negative value of αS\alpha_S, which is weakly preferred by current data.Comment: 26 pages, 5 figures, Refs. added, Minor textual change; version to appear in JCA

    High-accuracy relativistic many-body calculations of van der Waals coefficients C_6 for alkaline-earth atoms

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    Relativistic many-body calculations of van der Waals coefficients C_6 for dimers correlating to two ground state alkaline-earth atoms at large internuclear separations are reported. The following values and uncertainties were determined : C_6 = 214(3) for Be, 627(12) for Mg, 2221(15) for Ca, 3170(196) for Sr, and 5160(74) for Ba in atomic units.Comment: 5 pages, submitted to Phys. Rev.
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