3,442 research outputs found

    K to pi pi Amplitudes at Unphysical Kinematics Using Domain Wall Fermions

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    The use of chiral perturbation theory in extracting physical K to pi pi matrix elements from matrix elements calculated at unphysical kinematics is outlined. In particular, the possibility of utilizing pions with non-zero momentum in the final state, and of using partial quenching is discussed. Preliminary (not physically normalized) Delta I=3/2 (27,1) K to pi pi matrix elements are calculated on the RBC/UKQCD 243×6424^3 \times 64, Ls=16L_s=16 lattices, using 2+1 dynamical flavors and domain wall fermions, with an inverse lattice spacing of a−1=1.729(28)GeVa^{-1}=1.729(28) GeV. Effective mass plots are presented for a light sea quark mass of mlsea=0.005m_l^{sea}=0.005, and various valence quark masses. The plateaux are fit and Eππ−mKE_{\pi\pi}-m_K is extracted.Comment: 7 pages, 4 figures, Talk presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German

    X-rays From Quasars and Active Galaxies

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    Features of quasars and active galactic nuclei are discussed and include: the nature of the power source, the radiation processes, and the mechanism for the formation and collimation of long-lived jets of matter observed to emanate from the center of these of these objects. The phenomena that produce X-rays are highlighted

    A sore red eye with systemic involvement

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    The study of happiness has long been a playground for philosophical speculation. By lack of empirical measures of happiness, it was not possible to check propositions about the matter. In the late 20th century, survey-research methods introduced by the social sciences have brought a break-through. Dependable measures of happiness have developed, by means of which a significant body of knowledge has evolved

    Fundamental studies in X-ray astrophysics

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    An analytical model calculation of the ionization structure of matter accreting onto a degenerate dwarf was carried out. Self-consistent values of the various parameters are used. The possibility of nuclear burning of the accreting matter is included. We find the blackbody radiation emitted from the stellar surface keeps hydrogen and helium ionized out to distances much larger than a typical binary separation. Except for low mass stars or high accretion rates, the assumption of complete ionization of the elements heavier than helium is a good first approximation. For low mass stars or high accretion rates the validity of assuming complete ionization depends sensitivity on the distribution of matter in the binary system

    Topical prostaglandin analogues and conjunctival inflammation in uveitic glaucoma.

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    A pilot study to determine whether topical prostaglandin analogues alter the expression of conjunctival inflammatory markers in patients with uveitic glaucoma.Prospective, single-masked case series of 20 patients with uveitis and secondary raised intraocular pressure. Participants were divided into four groups of five patients dependent on their use of topical medication: (1) prostaglandin analogues only, (2) corticosteroids only, (3) both prostaglandin analogues and corticosteroids, (4) no topical medication. Conjunctival cells were harvested by impression cytology and were examined for inflammatory markers (CD3, CD54, HLA-DR, CCR4, CCR5) by flow cytometry. A tear fluid sample was also examined for inflammatory cytokines (IL-12p70, IL-2, IL-10, IL-8, IL-6, IL-4, IL-5, IFN-gamma, IL-1beta, IFN-alpha, IFN-beta) by multiplex bead arrays.All groups demonstrated increased markers of conjunctival inflammation. There was no significant difference in levels of any inflammatory markers between the four groups, suggesting that the use of topical prostaglandin analogues does not increase conjunctival levels of inflammation beyond those already seen in uveitis.The use of topical prostaglandins does not appear to induce conjunctival inflammation over that which is already present in patients with uveitic glaucoma. This supports the use of topical prostaglandin analogues in patients with uveitic glaucoma, indicating that their use is unlikely to adversely affect subsequent glaucoma filtration surgery through the induction of chronic conjunctival inflammation

    The International Scientific Series and the Communication of Darwinism?

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    This thesis notes that there is a lack of systematic research investigating segregation patterns based on how public space is used and frequented by citizens. In order for understanding of urban segregation to reach beyond residential segregation, the extent to which public space facilitates co-presence between social groups is a key issue. The main concern in this thesis is to arrive at a deeper understanding of the critical role urban form plays in terms of co-presence in public space and in extension for social segregation. The argument builds on knowledge from other fields, arguing that co-presence is of utmost importance for societal processes: by sharing space and being co-present with others, which does not necessarily imply focused interaction, we gain information and knowledge from our fellow citizens and participate in processes that negotiate social structures, acceptable behaviours and identities. The sharing of space thus becomes a central part of ‘being in society’. It is furthermore through public space that material urban resources are accessible, an access that is dependent on both the location of the amenities in space but also the distribution of space, as structured and shaped by urban form, which creates the actual experience of access through space. Segregation is primarily defined as a social problem. However, in this thesis, it is made clear that it is also a spatial problem. While also broadening the conceptualisation of segregation, the main focus has been upon the role of the built environment. The socio-spatial link builds on social theories. However, these theories are weak when it comes to explaining where co-presence occurs. Addressing the spatial side of the problem, the thesis primarily builds on the architectural theory of space syntax that exactly aims to study the space-society relationship from the viewpoint of space and provides empirical evidence for the correspondence between urban form – as it is shaped by urban design and architecture – and the creation of co-presence as well as variations in its intensity and its constitution. In addition, key questions such as what people may have access to ‘just around the corner’ in terms of human resources or other urban amenities are elaborated. The distinct variations found between neighbourhoods are argued both to enrich the discussion on social exclusion and unequal living conditions and inform future urban planning and design. The thesis demonstrates that specific configurational properties have great impact on the pattern of co-presence. More specifically, it is found that a segregation of public space, a limited spatial reach and an uneven distribution of spatial centrality appears not to favour an exchange between neighbourhoods or access to urban resources across the city – findings that are highly critical for the urban segregation issue. Detailed configurational analysis of Stockholm reveals the performative aspects of different urban layouts related not only to local circumstances and character but, more importantly, to the further context of such layouts. Increased knowledge of how spatial configuration relates to social practices offers new insight into how different neighbourhoods and urban layouts perform socially and increases understanding of the social implications of spatial configuration. The findings of this study are argued to open up theoretical developments that address the social and political dimension of urban design with greater precision. Not least, this knowledge can influence public debate. The knowledge produced can furthermore be used in urban design practice and anti-segregation initiatives, identifying whether spatial interventions can make a contribution and if so, what physical interventions respond to the social ends in question, where the ultimate aim is an urban design that not only builds cities but societies too.QC 20131108</p
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