2,756 research outputs found
Bunge’s Mathematical Structuralism Is Not a Fiction
In this paper, I explore Bunge’s fictionism in philosophy of mathematics. After an overview of Bunge’s views, in particular his mathematical structuralism, I argue that the comparison between mathematical objects and fictions ultimately fails. I then sketch a different ontology for mathematics, based on Thomasson’s metaphysical work. I conclude that mathematics deserves its own ontology, and that, in the end, much work remains to be done to clarify the various forms of dependence that are involved in mathematical knowledge, in particular its dependence on mental/brain states and material objects
Factors Affecting Laboratory Test Use and Prices
The use of clinical laboratory tests has more than doubled during the past decade. Some observers of the health system feel that this growth is excessive and is a result of current payment systems. This article examines the effects of current reimbursement policies with regard to the use of laboratory tests and prices charged for tests. The results suggest the following: The method of financing medical care, including cost sharing and prepaid group practice arrangements, affects the volume of laboratory testing through the number of patient contacts with the medical care system rather than through the number of tests used per patient contact. Fee ceilings on physician time appear to be partially offset by higher test prices. Cost-based reimbursement for hospital services is associated with higher charges in hospital laboratories
Reduced tillage in corn production
Caption title."Corn Belt Branch, Soil and Water Conservation Research Division, Agricultural Research Service, U.S. Department of Agriculture, Columbia, Missouri and the Agricultural Engineering Department of the Missouri Agricultural Experiment Station Cooperating"--Page [2]
A bacterial chloroform reductive dehalogenase: purification and biochemical characterization
© 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology. We report herein the purification of a chloroform (CF)-reducing enzyme, TmrA, from the membrane fraction of a strict anaerobe Dehalobacter sp. strain UNSWDHB to apparent homogeneity with an approximate 23-fold increase in relative purity compared to crude lysate. The membrane fraction obtained by ultracentrifugation was solubilized in Triton X-100 in the presence of glycerol, followed by purification by anion exchange chromatography. The molecular mass of the purified TmrA was determined to be 44.5 kDa by SDS-PAGE and MALDI-TOF/TOF. The purified dehalogenase reductively dechlorinated CF to dichloromethane in vitro with reduced methyl viologen as the electron donor at a specific activity of (1.27 ± 0.04) × 103units mg protein−1. The optimum temperature and pH for the activity were 45°C and 7.2, respectively. The UV-visible spectrometric analysis indicated the presence of a corrinoid and two [4Fe-4S] clusters, predicted from the amino acid sequence. This is the first report of the production, purification and biochemical characterization of a CF reductive dehalogenase
The definability criterions for convex projective polyhedral reflection groups
Following Vinberg, we find the criterions for a subgroup generated by
reflections \Gamma \subset \SL^{\pm}(n+1,\mathbb{R}) and its finite-index
subgroups to be definable over where is an integrally
closed Noetherian ring in the field . We apply the criterions for
groups generated by reflections that act cocompactly on irreducible properly
convex open subdomains of the -dimensional projective sphere. This gives a
method for constructing injective group homomorphisms from such Coxeter groups
to \SL^{\pm}(n+1,\mathbb{Z}). Finally we provide some examples of
\SL^{\pm}(n+1,\mathbb{Z})-representations of such Coxeter groups. In
particular, we consider simplicial reflection groups that are isomorphic to
hyperbolic simplicial groups and classify all the conjugacy classes of the
reflection subgroups in \SL^{\pm}(n+1,\mathbb{R}) that are definable over
. These were known by Goldman, Benoist, and so on previously.Comment: 31 pages, 8 figure
Stability of nanoscale secondary phases in an oxide dispersion strengthened Fe-12Cr alloy
Transmission electron microscopy and atom-probe tomography were used to characterize on a near-atomic scale the microstructure and oxide and carbide phases that form during thermo-mechanical treatments of a model oxide dispersion strengthened Fe-12 wt.% Cr-0.4 wt.% Y₂O₃ alloy. It was found that some of the Y-rich nanoparticles retained their initial crystallographic structure but developed a Cr-enriched shell, while others evolved into ternary oxide phases during the initial processing. The Y- and Cr-rich oxide phases formed remained stable after annealing at 1023 K for 96 h. However, the number of Cr-rich carbides appeared to increase, inducing Cr depletion in the matrix.the FP6 Euratom
Research and Training Programme on Nuclear Energy
(VdC), The Engineering and Physical Sciences
Research Council (SLP) and The Royal Society (EAM).
The Comunidad de Madrid, through the ESTRUMATCM
(MAT-77) programme, and the use of the Chemical
Database Service at DaresburyPublicad
Aerosol direct radiative effects under cloud-free conditions over highly-polluted areas in europe and mediterranean: A ten-years analysis (2007–2016)
This study investigates changes in aerosol radiative effects on two highly urbanized regions across the Euro-Mediterranean basin with respect to a natural desert region as Sahara over a decade through space-based lidar observations. The research is based on the monthly-averaged vertically-resolved aerosol optical depth (AOD) atmospheric profiles along a 1◦ × 1◦ horizontal grid, obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument measurements aboard the Cloud-Aerosol lidar and Infrared Pathfinder Satellite Observation (CALIPSO). To assess the variability of the anthropogenic aerosols on climate, we compared the aerosol vertical profile observations to a one-dimensional radiative transfer model in two metropolitan climate sensible hot-spots in Europe, namely the Po Valley and Benelux, to investigate the variability of the aerosol radiative effects and heating rate over ten years. The same analysis is carried out as reference on the Sahara desert region, considered subject just to natural local emission. Our findings show the efficacy of emission reduction policies implemented at government level in strongly urbanized regions. The total atmospheric column aerosol load reduction (not observed in Sahara desert region) in Po Valley and Benelux can be associated with: (i) an increase of the energy flux at the surface via direct effects confirmed also by long term surface temperature observations, (ii) a general decrease of the atmospheric column heating rate, and likely (iii) an increase in surface temperatures during a ten-year period. Summarizing, the analysis, based on the decade 2007–2016, clearly show an increase of solar irradiation under cloud-free conditions at the surface of +3.6 % and +16.6% for the Po Valley and Benelux, respectively, and a reduction of −9.0% for the Sahara Desert
Analytical characterisation of oxide dispersion strengthened steels for fusion reactors
Special issue articleReduced activation ferritic/martensitic and ferritic steels strengthened by a dispersion of oxide nanoparticles have been considered viable structural materials for fusion applications above 550°C. However, the microstructural stability and mechanical behaviour of these steels subjected
to the aggressive operating conditions of these reactors are not well known. An accelerated development of these materials is crucial if they are going to be used in future power reactors.
Then, it is indispensable to understand their atomic scale evolution under high temperature and irradiation conditions. The present paper reviews how the combination of transmission electron microscopy and atom probe tomography has been successfully applied for the characterisation of these steels at the near atomic scale, to reveal the nanoparticle structure, grain boundary
chemistry and void distribution.The present research has been supported by the FP6
Euratom Research and Training Programme on Nuclear
Energy, the Fusion Energy Materials Science (FEMaS)
FP7 coordination action, the IP3 FP6 ESTEEM project
under contract no. 026019 and the Consejería de
Educación de la Comunidad de Madrid, through the
program ESTRUMAT-CM S2009MAT-1585. EAM
thanks the Royal Society for the financial support (RS
Dorothy Hodgkin fellowship)
Report of the GDR working group on the R-parity violation
This report summarizes the work of the "R-parity violation group" of the
French Research Network (GDR) in Supersymmetry, concerning the physics of
supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron
and LHC and limits on R-parity violating couplings from various processes. The
report includes a discussion of the recent searches at the HERA experiment,
prospects for new experiments, a review of the existing limits, and also
theoretically motivated alternatives to R-parity and a brief discussion on the
implications of R-parity violation on the neutrino masses.Comment: 60 pages, LaTeX, 22 figures, 2 table
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