The Yoneda algebra of a graded Ore extension

Let A be a connected-graded algebra with trivial module k, and let B be a graded Ore extension of A. We relate the structure of the Yoneda algebra E(A) := Ext_A(k,k) to E(B). Cassidy and Shelton have shown that when A satisfies their K_2 property, B will also be K_2. We prove the converse of this result.Comment: 9 page

Linear response within the projection-based renormalization method: Many-body corrections beyond the random phase approximation

The explicit evaluation of linear response coefficients for interacting many-particle systems still poses a considerable challenge to theoreticians. In this work we use a novel many-particle renormalization technique, the so-called projector-based renormalization method, to show how such coefficients can systematically be evaluated. To demonstrate the prospects and power of our approach we consider the dynamical wave-vector dependent spin susceptibility of the two-dimensional Hubbard model and also determine the subsequent magnetic phase diagram close to half-filling. We show that the superior treatment of (Coulomb) correlation and fluctuation effects within the projector-based renormalization method significantly improves the standard random phase approximation results.Comment: 17 pages, 7 figures, revised versio

Faxen relations in solids - a generalized approach to particle motion in elasticity and viscoelasticity

A movable inclusion in an elastic material oscillates as a rigid body with six degrees of freedom. Displacement/rotation and force/moment tensors which express the motion of the inclusion in terms of the displacement and force at arbitrary exterior points are introduced. Using reciprocity arguments two general identities are derived relating these tensors. Applications of the identities to spherical particles provide several new results, including simple expressions for the force and moment on the particle due to plane wave excitation.Comment: 11 pages, 4 figure

The investigation of Spatial Delight and Environmental Performance of Modernist Architecture in London – Golden Lane Estate

This paper investigated the spatial delight and environmental performance of two selected apartments in the modernist buildings at Golden Lane Estate built after the 2nd World War. This estate is a Grade II listed, high density, low cost housing complex designed by three young architects: Peter Chamberlin, Geoffrey Powell and Christof Bon and it was built over a bombed site, and well embraced the post-war modern architecture ethos, environmental considerations and inclusion of social facilities and landscaped communal spaces. Two apartments in different building blocks with similar size, orientation, internal layout, use of materials and building elements were chosen for this study. However, one apartment has been refurbished with internal insulation and secondary glazing for improving the comfort conditions. Through fieldwork, which included on-site monitoring and interview of the building occupants, first-hand information on the environmental and comfort conditions inside the apartments were obtained. Through performance based theoretical analysis, the comfort conditions in the apartments and energy consumption were critically assessed. The research findings indicate that through selective enhancement of the thermal property of the building envelopes by internal insulation, introduction of secondary glazing over the original single glazed windows and the improvement on the air tightness in the apartments, the original naturally ventilated and well day-lit living environments were maintained while the overall comfort level was significantly improved. This paper presents the feasible strategies to deal with the environmental challenges in the post-war Grade II listed residential buildings in the UK

Predictors and patterns of weight gain during treatment for tuberculosis in the United States of America

SummaryObjectivesPatients with tuberculosis (TB) often present with weight loss. Lack of weight gain with TB treatment has been associated with treatment failure. The purpose of this study was to examine patterns of weight gain in patients with TB and determine the disease characteristics that predict weight gain.MethodsThis was a retrospective cohort study of adults with TB treated in a county health system in the USA. Demographic, clinical, radiographic, and microbiological data were recorded in addition to monthly weights during treatment.ResultsOverall, patients had a significant change in weight over the course of treatment (p<0.0001). After 2 months of treatment, 31.9% of patients had gained at least 5% body weight; by the end of treatment, 62.4% of patients had gained at least 5% weight. Patients who gained weight did so in a linear fashion throughout treatment. Cavitary and extensive disease, a positive smear, and a positive culture were predictors of weight gain (p<0.05). No patients had relapses during the time period of the study.ConclusionsOnly a subset of patients treated for TB gain significant weight. A greater burden of disease was predictive of weight gain

Detection of lithium in nearby young late-M dwarfs

Late M-type dwarfs in the solar neighborhood include a mixture of very low-mass stars and brown dwarfs which is difficult to disentangle due to the lack of constraints on their age such as trigonometric parallax, lithium detection and space velocity. We search for young brown dwarf candidates among a sample of 28 nearby late-M dwarfs with spectral types between M5.0 and M9.0, and we also search for debris disks around three of them. Based on theoretical models, we used the color $I-J$, the $J$-band absolute magnitude and the detection of the Li I 6708 $\AA$ doublet line as a strong constraint to estimate masses and ages of our targets. For the search of debris disks, we observed three targets at submillimeter wavelength of 850 $\mu$m. We report here the first clear detections of lithium absorption in four targets and a marginal detection in one target. Our mass estimates indicate that two of them are young brown dwarfs, two are young brown dwarf candidates and one is a young very low-mass star. The closest young field brown dwarf in our sample at only $\sim$15 pc is an excellent benchmark for further studying physical properties of brown dwarfs in the range 100$-$150 Myr. We did not detect any debris disks around three late-M dwarfs, and we estimated upper limits to the dust mass of debris disks around them.Comment: 10 pages, 5 figures, accepted for publication in Astronomy and Astrophysic