Systematic study of autocorrelation time in pure SU(3) lattice gauge theory

Results of our autocorrelation measurement performed on Fujitsu AP1000 are reported. We analyze (i) typical autocorrelation time, (ii) optimal mixing ratio between overrelaxation and pseudo-heatbath and (iii) critical behavior of autocorrelation time around cross-over region with high statistic in wide range of $\beta$ for pure SU(3) lattice gauge theory on $8^4$, $16^4$ and $32^4$ lattices. For the mixing ratio K, small value (3-7) looks optimal in the confined region, and reduces the integrated autocorrelation time by a factor 2-4 compared to the pseudo-heatbath. On the other hand in the deconfined phase, correlation times are short, and overrelaxation does not seem to matter For a fixed value of K(=9 in this paper), the dynamical exponent of overrelaxation is consistent with 2 Autocorrelation measurement of the topological charge on $32^3 \times 64$ lattice at $\beta$ = 6.0 is also briefly mentioned.Comment: 3 pages of A4 format including 7-figure

Non-perturbative determination of anisotropy coefficients and pressure gap at the deconfining transition of QCD

We propose a new non-perturbative method to compute derivatives of gauge coupling constants with respect to anisotropic lattice spacings (anisotropy coefficients). Our method is based on a precise measurement of the finite temperature deconfining transition curve in the lattice coupling parameter space extended to anisotropic lattices by applying the spectral density method. We determine the anisotropy coefficients for the cases of SU(2) and SU(3) gauge theories. A longstanding problem, when one uses the perturbative anisotropy coefficients, is a non-vanishing pressure gap at the deconfining transition point in the SU(3) gauge theory. Using our non-perturbative anisotropy coefficients, we find that this problem is completely resolved.Comment: LATTICE98(hightemp

Autocorrelation in Updating Pure SU(3) Lattice Gauge Theory by the use of Overrelaxed Algorithms

We measure the sweep-to-sweep autocorrelations of blocked loops below and above the deconfinement transition for SU(3) on a $16^4$ lattice using 20000-140000 Monte-Carlo updating sweeps. A divergence of the autocorrelation time toward the critical $\beta$ is seen at high blocking levels. The peak is near $\beta$ = 6.33 where we observe 440 $\pm$ 210 for the autocorrelation time of $1\times 1$ Wilson loop on $2^4$ blocked lattice. The mixing of 7 Brown-Woch overrelaxation steps followed by one pseudo-heat-bath step appears optimal to reduce the autocorrelation time below the critical $\beta$. Above the critical $\beta$, however, no clear difference between these two algorithms can be seen and the system decorrelates rather fast.Comment: 4 pages of A4 format including 6-figure

Non-perturbative determination of anisotropy coefficients in lattice gauge theories

We propose a new non-perturbative method to compute derivatives of gauge coupling constants with respect to anisotropic lattice spacings (anisotropy coefficients), which are required in an evaluation of thermodynamic quantities from numerical simulations on the lattice. Our method is based on a precise measurement of the finite temperature deconfining transition curve in the lattice coupling parameter space extended to anisotropic lattices by applying the spectral density method. We test the method for the cases of SU(2) and SU(3) gauge theories at the deconfining transition point on lattices with the lattice size in the time direction $N_t=4$ -- 6. In both cases, there is a clear discrepancy between our results and perturbative values. A longstanding problem, when one uses the perturbative anisotropy coefficients, is a non-vanishing pressure gap at the deconfining transition point in the SU(3) gauge theory. Using our non-perturbative anisotropy coefficients, we find that this problem is completely resolved: we obtain $\Delta p/T^4 = 0.001(15)$ and $-0.003(17)$ on $N_t=4$ and 6 lattices, respectively.Comment: 24pages,7figures,5table

Scaling Study of Pure Gauge Lattice QCD by Monte Carlo Renormalization Group Method

The scaling behavior of pure gauge SU(3) in the region $\beta=5.85 - 7.60$ is examined by a Monte Carlo Renormalization Group analysis. The coupling shifts induced by factor 2 blocking are measured both on 32$^4$ and 16$^4$ lattices with high statistics. A systematic deviation from naive 2-loop scaling is clearly seen. The mean field and effective coupling constant schemes explain part, but not all of the deviation. It can be accounted for by a suitable change of coupling constant, including a correction term ${\cal O}(g^7)$ in the 2-loop lattice $\beta$-function. Based on this improvement, $\sqrt{\sigma}/\Lambda_{\overline {MS}}^{n_f=0}$ is estimated to be $2.2(\pm 0.1)$ from the analysis of the string tension $\sigma$.Comment: 4 pages of A4 format including 7-postscript figure

Hadron Properties just before Deconfinement

We have investigated hadron screening masses, the chiral condensate, and the pion decay constant close to the deconfinement phase transition in the confined phase of QCD. The simulations were done in the quenched approximation, on a lattice of size \mbox{$32^{3}\times 8$}. We examined temperatures ranging from 0.75\tc up to 0.92\tc. We see no sign of a temperature dependence in the chiral condensate or the meson properties, but some temperature dependence for the nucleon screening mass is not excluded.Comment: Postscript file, uuencoded compresse

Scaling Properties of the Energy Density in SU(2) Lattice Gauge Theory

The lattice data for the energy density of $SU(2)$ gauge theory are calculated with \nop~derivatives of the coupling constants. These derivatives are obtained from two sources : i) a parametrization of the \nop~beta function in accord with the measured critical temperature and $\Delta\beta-$values and ii) a \nop~calculation of the presssure. We then perform a detailed finite size scaling analysis of the energy density near $T_c$. It is shown that at the critical temperature the energy density is scaling as a function of $VT^3$ with the corresponding $3d$ Ising model critical exponents. The value of $\epsilon(T_c)/T^4_c$ in the continuum limit is estimated to be 0.256(23). In the high temperature regime the energy density is approaching its weak coupling limit from below, at $T/T_c \approx 2$ it has reached only about $70\%$ of the limit.Comment: 15 pages + 9 figures, BI-TP 94/3

Identificação molecular de Bartonella henselae em paciente com SIDA soronegativo para doença da arranhadura do gato no Rio de Janeiro, Brasil

Bartonella henselae is associated with a wide spectrum of clinical manifestations, including cat scratch disease, endocarditis and meningoencephalitis, in immunocompetent and immunocompromised patients. We report the first molecularly confirmed case of B. henselae infection in an AIDS patient in state of Rio de Janeiro, Brazil. Although DNA sequence of B. henselae has been detected by polymerase chain reaction in a lymph node biopsy, acute and convalescent sera were nonreactive.Bartonella henselae está associada a um amplo espectro de manifestações clínicas, incluindo a doença da arranhadura de gato, endocardite, e meningoencefalite, em pacientes imunocompetentes e imunocomprometidos. Relatamos o primeiro caso confirmado por método molecular de B. henselae em um paciente com SIDA no estado do Rio de Janeiro, Brasil. Apesar da sequência de DNA de B. henselae ser detectada pela reação em cadeia da polimerase em uma biópsia do linfonodo, soros das fases aguda e convalescente foram não reativos

A PROBLEMÁTICA DO MONITORAMENTO DAS INFECÇÕES DE SÍTIO CIRÚRGICO E A NECESSIDADE DE PADRONIZAÇÃO DE CRITÉRIOS PARA SEU DIAGNÓSTICO E NOTIFICAÇÃO.

Las infecciones hospitalarias (IH) ocurren como un problema de salud pública mundial, siendo la Infección del Sitio Quirúrgico la tercera topografia más común, de 14% a 16% de todas las IH. Cuando un paciente muere por una causa asociada a la IH, 77% están relacionadas con la ISC; 93% de ellas con infecciones serias que invaden órganos o espacios accedidos durante un procedimiento quirúrgico. Directamente, las repercusiones de las ISC aparecen en los costos hospitalarios, pues aumentan la permanencia hospitalaria entre 7 a 10 días, amén de las readmisiones; pero, de manera indirecta, igualmente o más importante, están los costos indirectos que causan impactos emocionales desastrosos en los pacientes y en la familia. Los criterios más utilizados para diagnóstico de ISC son los Centers for Diseases Control (CDC); otros criterios desarrollados por especialistas ingleses como el National Prevalence Survey Study (NPS) también son utilizados. El objetivo de este estudio fue buscar una respuesta, en la literatura, para la práctica del controlador de infección hospitalaria en lo que respecta a la existencia de un “patrón-oro” para el diagnóstico de ISC, con el fin de soportar los resultados obtenidos y las consecuentes acciones. Una revisión sistemática ha mostrado que comparándose las definiciones del CDC y NPS de 93 heridas operatorias, 24% han quedado sin diagnóstico al utilizarse criterios del CDC y 19% cuando se utilizaron criterios del NPS. La conclusión de este estudio es que no hay un “patrón-oro” para el diagnóstico de ISC, pues el juicio es subjetivo, y sujeto a variaciones de acuerdo con el observador. Es necesario que cada servicio de salud junto al grupo Comissão de Controle de Infeccção Hospitalar -CCIH (Comisión de Control de Infección Hospitalaria) asuma y reglamente, por medio de la mejor evidencia científica, cuáles son los mejores criterios para diagnóstico y notificación de ISC, cuál es el mejor método de trabajo para vigilancia después del alta, teniendo en cuenta la factibilidad y las necesidades locales.As infecções hospitalares (IH) surgem como um problema de saúde pública mundial sendo a Infecção de Sítio Cirúrgico (ISC) a terceira topografia mais comum, de 14% a 16% de todas as IH. Quando um paciente morre por causa associada à IH, 77% estão relacionadas a ISC; 93% deles com infecções sérias que invadem órgãos ou espaços acessados durante o procedimento cirúrgico. Diretamente, as repercussões das ISC aparecem nos custos hospitalares pois aumentam a permanência hospitalar entre 7 a 10 dias, além das readmissões; mas de forma indireta e tão ou mais importante, estão os custos indiretos que provocam impactos emocionais desastrosos nos pacientes e familiares. Os critérios mais utilizados para diagnóstico de ISC são os do Centers for Diseases Control (CDC), outros critérios desenvolvidos por especialistas ingleses como o National Prevalence Survey Study (NPS) também são utilizados. O objetivo deste estudo foi buscar resposta, na literatura, para a pratica do controlador de infecção hospitalar no que tange a existência de um padrão ouro para o diagnostico de ISC, a fim de respaldar os resultados obtidos e as conseqüentes ações. Uma revisão sistemática mostrou que se comparando as definições do CDC e NPS de 93 feridas operatórias, 24% ficaram sem diagnóstico quando usados critérios do CDC e 19% quando usados critérios do NPS. A conclusão deste estudo é que não há padrão ouro, no diagnóstico de ISC, pois o julgamento é subjetivo e sujeito a variações de acordo com o observador. É preciso que cada serviço de saúde, junto ao grupo da Comissão de Controle de Infecção Hospitalar (CCIH) assuma e normatize, por meio da melhor evidência científica, quais os melhores critérios para diagnóstico e notificação de ISC, qual o melhor método de trabalho para vigilância no pós-alta; levando em conta a factibilidade e as necessidades locais