375,538 research outputs found
Scaling and asymptotic scaling in the SU(2) gauge theory
No full textFingberg J, Heller UM, Karsch F. Scaling and asymptotic scaling in the SU(2) gauge theory. Nuclear Physics, B. 1993;392(2):493-517.We determine the critical couplings for the deconfinement phase transition in SU(2) gauge theory on N(tau) x N(sigma)3 lattices with N(tau) = 8 and 16 and N(sigma) varying between 16 and 48. A comparison with string tension data shows scaling of the ratio T(c)/square-root sigma in the entire coupling regime beta = 2.30-2.75, while the individual quantities still exhibit large scaling violations. We find T(c)/square-root sigma = 0.69(2). We also discuss in detail the extrapolation of T(c)/LAMBDA(MSBAR) and square-root sigma/LAMBDA(MSBAR) to the continuum limit. Our result, which is consistent with the above ratio, is T(c)/LAMBDA(MSBAR) = 1.23(11) and square-root sigma/LAMBDA(MSBAR) = 1.79(12). We also comment upon corresponding results for SU(3) gauge theory and four-flavour QCD
Design and fabrication of an ac-electro-osmosis micropump with 3D high-aspect-ratio electrodes using only SU-8
No full textLab-on-a-chip devices require integrated pumping and fluid control in microchannels. A recently developed mechanism that can produce fluid flow is an integrated ac-electro-osmosis micropump. However, like most electrokinetic pumps, ac-electro-osmotic pumps are incapable of handling backpressure as the pumping force mechanism acts on the surface of the fluid rather than the bulk. This paper presents a novel 3D electrode structure designed to overcome this limitation. The electrodes are fabricated using carbon-MEMS technology based on the pyrolysis of the photo-patternable polymer SU-8. The novel ac-electro-osmosis micropump shows an increase in the flow velocity compared to planar electrodes
Glueball mass estimate from finite temperature SU(2) lattice studies
No full textEngels J, Karsch F, Satz H, Montvay I. Glueball mass estimate from finite temperature SU(2) lattice studies. Physics Letters, B. 1981;102(5):332-336
Non-perturbative thermodynamics of SU (N) gauge theories
No full textEngels J, Fingberg J, Karsch F, Miller D, Weber M. Non-perturbative thermodynamics of SU (N) gauge theories. Physics Letters, B. 1990;252(4):625-630.The pressure near the deconfinement transition as determined up to now in lattice gauge theories shows unphysical behaviour: it can become negative and may in SU (3) even have a gap at the transition. This has been attributed to the use of only perturbatively known derivatives of coupling constants. We propose a method to evaluate the pressure, which works without these derivatives, and is valid on large lattices. In SU (2) we study the finite-volume effects and show that for lattices with spatial extent N-sigma greater-than-or-similar-to 15 these effects are negligible. In SU (3) we then ontain a postive and continuous pressure. The influence of non-perturbative corrections to the beta-function on the energy density are investigated and found to be important, in particular for the latent heat
Ultrasonic transducers for wideband attenuation measurements
No full textIncludes bibliographical references.An application of ultrasound presently being investigated at the Council for Mineral Technology {MINTEK) is the measurement of the concentration of graphite particles in suspension in an agitated pulp. The principle of the measurement is based on the attenuation characteristics of the medium over a frequency range extending from 0.1 MHz to 10 MHz. This wide range and the highly attenuating medium (typically 3 dB/cm) require therefore that the ultrasonic transducers exhibit efficient wideband characteristics. Piezoceramic transducers vibrating in thickness-mode are the most suitable to generate ultrasound at these frequencies. However, their high acoustic impedances relative to their liquid loads make them inherently narrowband and inefficient. To overcome these undesirable features, impedance matching techniques are used whereby the impedance mismatch between a transducer and its load is reduced. In this thesis, various electrical and acoustic impedance matching schemes were implemented on a number of conunercial PZTSA transducers which were then evaluated in terms of bandwidth and efficiency. At 1 MHz, the 3-dB bandwidth of a PZTSA transducer operating in pulse-echo mode in water was improved from 0. 1 MHz for the unmat.ched case to 0. 83 MHz when 2 quarter-wave matching sections were bonded to the radiating surf ace and an electrical matching section was inserted at the electrical port. The resulting 2-way Insertion Loss over the pass band was 16 dB. Similarly, the 3-dB bandwidth of a 500 kHz PZTSA transducer improved from 50 kHz to 138 kHz with an accompanying Insertion Loss of 12 dB when both electrical and acoustic impedance matching were implemented. Certain radiation characteristics of thickness-mode transducers such as beam directivity and radiation resistance were investigated as functions of the "diameter to wavelength" ratio, D/)... , of the radiating transducer. Maximum radiation resistance (and therefore maximum acoustic coupling) was observed when D/ .A =13. The same ratio also produced the best performance in terms of directivity and sensitivity to parallelism between transmitter and reflector {or receiver). A comprehensive study of the resonance spectra of flexural, in-plane and thickness-mode vibrations of thin disks was also performed using various materials commonly used in transducer construction. The elastic constants of the materials were then determined by three different methods, each method making use of a different resonance spectrum
A Report of the Mosquito Host Range of Pythium guiyangense Su
No full textMosquito causes problems in both disease transmission and disturbance to people's daily life. The controlling methods used now are mainly application of chemical pesticides which result in serious harm to environment. Biological control of the pest is one of the ideal ways. But, lack of suitable agent makes it difficult to extend this technique in wider scope. _Pythium guiyangense_ Su is a newly found fungal pathogen of mosquitoes and is promising for practical use. Here we summarize a list of mosquitoes that can be infected by the fungus so far, which shows the potential significance of the application of the fungus in the future
High temperature SU(2) gluon matter of the lattice
No full textEngels J, Karsch F, Satz H, Montvay I. High temperature SU(2) gluon matter of the lattice. Physics Letters, B. 1981;101(1-2):89-94.We calculate by Monte Carlo simulation on the lattice the energy density [epsilon] of an SU(2) Yang-Mills system at finite physical temperature. First, we study the high temperature form of [epsilon], showing that the conventional euclidean lattice formulation converges to the parameter-free Stefan-Boltzmann limit of a free gluon gas in the continuum. Secondly, we show that the specific heat of gluon matter exhibits a sharp peak at the transition point from the confined phase to the color-screened gluon gas. The resulting transition temperature is found to be 210 ± 10 MeV
Suppression of non-prompt J/ψ, prompt J/ψ, and Y(1S) in PbPb collisions at √s NN = 2.76 TeV
No full textThis is the Pre-print verison of the Article. The official published version can be accessed from the link below - Copyright @ 2012 Springer VerlagYields of prompt and non-prompt J/ψ, as well as U (1S) mesons, are measured by the CMS experiment via their μ + μ − decays in PbPb and pp collisions at Ö{s\textNN} = 2.76 sNN=276 TeV for quarkonium rapidity |y| < 2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum p T, as well as collision centrality. For prompt J/ψ with relatively high p T (6.5 < p T < 30 GeV/c), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. In the same kinematic range, a suppression of non-prompt J/ψ, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Also the low-p T U (1S) mesons are suppressed in PbPb collisions.This work was supported by the Austrian Federal Ministry of Science and Research; the Belgium Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk
Onderzoek; the Brazilian Funding Agencies (CNPq, CAPES, FAPERJ, and FAPESP); the Bulgarian Ministry of Education and Science; CERN; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China; the Colombian Funding Agency (COLCIENCIAS); the Croatian Ministry of Science, Education and Sport; the Research Promotion Foundation, Cyprus; the Estonian Academy of Sciences and NICPB; the Academy of Finland, Finnish Ministry of Education and Culture, and Helsinki Institute of
Physics; the Institut National de Physique Nucl´eaire et de Physique des Particules / CNRS, and Commissariat a l’Energie Atomique et aux Energies Alternatives / CEA, France; the Bundesministerium fur Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz-Gemeinschaft Deutscher Forschungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Office for
Research and Technology, Hungary; the Department of Atomic Energy and the Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean
Ministry of Education, Science and Technology and the World Class University program of NRF, Korea; the Lithuanian Academy of Sciences; the Mexican Funding Agencies (CINVESTAV, CONACYT, SEP, and UASLP-FAI); the Ministry of Science and Innovation, New Zealand; the Pakistan Atomic Energy Commission; the Ministry of Science and Higher Education and the National Science Centre, Poland; the Fundac¸ ao para a Ciencia e a Tecnologia, Portugal; JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); the Ministry of Education and Science of the Russian Federation, the Federal Agency of Atomic Energy of the Russian Federation, Russian Academy of Sciences, and the Russian Foundation for Basic Research; the Ministry of Science and Technological Development of Serbia; the Ministerio de Ciencia e Innovacion, and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH, Canton Zurich, and SER); the National Science Council, Taipei; the Scientific and Technical Research Council of Turkey, and Turkish Atomic Energy Authority; the Science and Technology Facilities Council, UK; the US Department of Energy, and the US National Science Foundation
Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
No full textMultiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis
A proof of concept of a BioMEMS glucose biosensor using microfabricated SU-8 films
No full textThe present project investigated and proved the concept of developing a novel
BioMEMS glucose micro-biosensor using a simple one-step microfabrication process of
the widely used SU-8 polymer. More specifically, the study focused on the investigation
of the suitability of the SU-8 polymer as a matrix for enzyme immobilisation that is
carried out during the microfabrication process. A comparative study between
commercially available SU-8 and “customised” SU-8 solutions showed that the
optimum concentration of photo-initiator for stress reduction can be achieved easier
with “customised” SU-8 solutions. The most appropriate type of microstructure for the
SU-8 matrix and the corresponding required microfabrication process were defined and
encapsulation of the enzyme GOx in the SU-8 solution was accomplished. A detailed
experimental investigation of the immobilised enzyme’s activity inside the SU-8 matrix,
was carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup.
SU-8 films were immersed in a buffer solution and the platinum working electrode
was brought in close contact with the film. Films without enzyme showed negligible
variation in current upon the addition of glucose, as opposed to films with encapsulated
enzyme which showed a very clear increase in current. Experiments using films of
increased thickness or enzyme concentration, showed a higher response, thus proving
that the enzyme remained active not only on the film’s surface, but inside the matrix as
well. In the fluorescence spectroscopy experiments, the utilisation of the tris (4,7-
diphenyl-1,10-phenanthroline) ruthenium(II) dichloride oxygen indicator, which was
also captured in the polymer matrix during the microfabrication process, was proven to
be very sensitive to glucose concentration changes during the glucose oxidation and
there was no photo-bleaching.
The experimental investigations proved that the proposed concept of using SU-8
matrices for the immobilisation of biomolecules, is a valid proposal for the construction
of a BioMEMS glucose biosensor. An important outcome was the successful
immobilisation of glucose oxidase in SU-8 microfabricated structures. The enzyme still
showed activity despite the “hostile” conditions during microfabrication The proof of
principle of enzyme immobilisation in SU-8 films opens up new possibilities for
combining BioMEMS with biosensors and organic electronics
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