1,104 research outputs found
On the asymptotic magnitude of subsets of Euclidean space
Magnitude is a canonical invariant of finite metric spaces which has its
origins in category theory; it is analogous to cardinality of finite sets.
Here, by approximating certain compact subsets of Euclidean space with finite
subsets, the magnitudes of line segments, circles and Cantor sets are defined
and calculated. It is observed that asymptotically these satisfy the
inclusion-exclusion principle, relating them to intrinsic volumes of polyconvex
sets.Comment: 23 pages. Version 2: updated to reflect more recent work, in
particular, the approximation method is now known to calculate (rather than
merely define) the magnitude; also minor alterations such as references adde
Antithrombin Budapest 3 An antithrombin variant with reduced heparin affinity resulting from the substitution L99F
AbstractThe molecular basis and functional properties of a variant antithrombin (AT) protein. AT Budapest 3, were studied. A single base substitution was identified in codon 99, CTCâTTC, altering the normal leucine to phenylalanine. The proband presented with a history of venous thrombotic disease and was found to be homozygous for the mutation. The variant protein demonstrated reduced heparin affinity and reduced antiproteinase activity in the presence of either unfractionated heparin or the AT-binding heparin pentasaccharide, when compared to normal AT. A small change in the isoelectric point was also identified. The substituted amino acid residue of AT Budapest 3 is located near to the proposed AT heparin binding site, and it is suggested that reduced heparin affinity of the variant protein may result from substitution-induced distortion of positive charge geometry in the binding site and/or changes in its position relative to the rest of the inhibitor molecule
Electronic structure and superconductivity of Europium
We have calculated the electronic structure of Eu for the bcc, hcp, and fcc
crystal structures for volumes near equilibrium up to a calculated 90 GPa
pressure using the augmented-plane wave method in the local-density
approximation. The frozen-core approximation was used with a semi-empirical
shift of the f-states energies in the radial Schrdinger equation to
move the occupied 4f valence states below the energy and into the
core. This shift of the highly localized f-states yields the correct europium
phase ordering with lattice parameters and bulk moduli in good agreement with
experimental data. The calculated superconductivity properties under pressure
for the and structures are also found to agree with and
follow a trend similar to recent measurement by Debessai et al.Comment: 8 page
RCPE UK consensus conference on 'Approaching the comprehensive management of atrial fibrillation: evolution or revolution?'
Non-commutative desingularization of determinantal varieties, I
We show that determinantal varieties defined by maximal minors of a generic
matrix have a non-commutative desingularization, in that we construct a maximal
Cohen-Macaulay module over such a variety whose endomorphism ring is
Cohen-Macaulay and has finite global dimension. In the case of the determinant
of a square matrix, this gives a non-commutative crepant resolution.Comment: 52 pages, 3 figures, all comments welcom
Neutral top-pion and lepton flavor violating processes
In the context of topcolor-assisted techicolor(TC2) models, we study the
contributions of the neutral top-pion to the lepton flavor
violating(LFV) processes and .
We find that the present experimental bound on gives severe
constraints on the free parameters of models. Taking into account these
constraints, we consider the processes generated by
top-pion exchange at the tree-level and the one loop level, and obtain
, , in most of
the parameter space.Comment: latex files,16 pages, 6 figures. Submitted to Phys. Rev.
Autoantibodies against EPCR are found in antiphospholipid syndrome and are a risk factor for fetal death
The antiphospholipid syndrome (APS) is associated with thrombosis and fetal death but the pathologic mechanisms are poorly understood. Since endothelial protein C receptor (EPCR) plays a role in the anticoagulant system and in placental development, we hypothesized that anti-EPCR autoantibodies may be involved in clinical manifestations of APS and in fetal loss. The levels of immunoglobulin M (IgM) and IgG anti-EPCR autoantibodies were analyzed by enzyme-linked immunosorbent assay (ELISA) in 43 patients with APS and 43 controls. Anti-EPCR levels were higher in APS patients than in controls. Interestingly, one of the IgM anti-EPCR autoantibodies inhibited the generation of activated protein C on endothelium. Since markedly high anti-EPCR levels were found in women with fetal death, 87 patients with a first episode of unexplained fetal death were subsequently analyzed and their anti-EPCR levels were compared with 87 matched controls. We found that anti-EPCR autoantibodies constitute an independent risk factor for a first fetal death episode: the adjusted odds ratios (ORs) for anti-EPCR autoantibodies above the 95th percentile were 23.0 (95% confidence interval [CI], 2.0-266.3) for IgM and 6.8 (95% CI, 1.2-38.4) for IgG. Anti-EPCR autoantibodies can be detected in APS patients and are independent risk factors for fetal death
The institutional shaping of management: in the tracks of English individualism
Globalisation raises important questions about the shaping of economic action by cultural factors. This article explores the formation of what is seen by some as a prime influence on the formation of British management: individualism. Drawing on a range of historical sources, it argues for a comparative approach. In this case, the primary comparison drawn is between England and Scotland. The contention is that there is a systemic approach to authority in Scotland that can be contrasted to a personal approach in England. An examination of the careers of a number of Scottish pioneers of management suggests the roots of this systemic approach in practices of church governance. Ultimately this systemic approach was to take a secondary role to the personal approach engendered by institutions like the universities of Oxford and Cambridge, but it found more success in the different institutional context of the USA. The complexities of dealing with historical evidence are stressed, as is the value of taking a comparative approach. In this case this indicates a need to take religious practice as seriously as religious belief as a source of transferable practice. The article suggests that management should not be seen as a simple response to economic imperatives, but as shaped by the social and cultural context from which it emerges
Associated production of neutral toppion with a pair of heavy quarks in collisions
We have studied a neutral toppion production process in the topcolor-assisted technicolor(TC2) model. We
find that the cross section of is much
larger than that of . On the other hand,
the cross section can be obviously enhanced with the increasing of c.m.energy.
With GeV, the cross section of production can
reach the level of a few fb. The results show that is the most ideal channel to detect
neutral toppion due to the clean SM background. With such sufficient signals
and clean background, neutral toppion could be detected at TESLA with high
c.m.energy.Comment: 11 pages, 5 figure
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