Dynkin isomorphism and mermin-wagner theorems for hyperbolic sigma models and recurrence of the two-dimensional vertex-reinforced jump process

We prove the vertex-reinforced jump process (VRJP) is recurrent in two dimensions for any translation invariant finite range initial rates. Our proof has two main ingredients. The first is a direct connection between the VRJP and sigma models whose target space is a hyperbolic space $\mathbb{H}^n$ or its supersymmetric counterpart $\mathbb{H}^{2|2}$. These results are analogues of well-known relations between the Gaussian free field and the local times of simple random walk. The second ingredient is a Mermin--Wagner theorem for these sigma models. This result is of intrinsic interest for the sigma models and also implies our main theorem on the VRJP. Surprisingly, our Mermin--Wagner theorem applies even though the symmetry groups of $\mathbb{H}^n$ and $\mathbb{H}^{2|2}$ are non-amenable

Математические журналы и их интернационализация: первый португальский журнал “Jornal de sciencias mathematicas e astronomicas”

The article describes the historical place of the first Portuguese Journal “Jornal de sciencias mathematicas e astronómicas” (Teixeira´s Journal) during the development of the European mathematical community at the end of the 19th century

Salmonella in pigs and pork and their antimicrobial resistance - 10 years of surveillance in Germany

Salmonella from pigs and pork have been submitted to the National Reference Laboratory for the Analysis and Testing of Zoonoses (Salmonella) (NRL Salm) for a number of years. This study retrospectively analyses the data of Salmonella and their antimicrobial resistance generated between 2000 and 2009. A total of 4163 isolates from pigs and 1839 isolates from pork submitted to the NRL Salm were serotyped and tested for antimicrobial resistance using the broth microdilution method. Minimum inhibitory concentrations (MIC) were evaluated using epidemiological cut-off values as provided by EUCAST (www.eucast.org) at the time of interpretation (2010). The majority of isolates from pigs and pork belonged to three serovars: S. Typhimurium (66 and 52%), monophasic variant of S. Typhimurium (1,4,[5],12:i:-) (11 and 10%) and S. Derby (7 and 10%). In both origins the number of S. Typhimurium decreased by roughly 50% while monophasic variant of S. Typhimurium increased from zero to 32 and 26%, respectively. The proportion of S. Derby varied between 5 and 12% in both origins

Doping nature of native defects in 1T−TiSe₂

The transition-metal dichalcogenide 1T−TiSe₂is a quasi-two-dimensional layered material with a charge density wave (CDW) transition temperature of TCDW≈200  K. Self-doping effects for crystals grown at different temperatures introduce structural defects, modify the temperature-dependent resistivity, and strongly perturbate the CDW phase. Here, we study the structural and doping nature of such native defects combining scanning tunneling microscopy or spectroscopy and ab initio calculations. The dominant native single atom dopants we identify in our single crystals are intercalated Ti atoms, Se vacancies, and Se substitutions by residual iodine and oxygen

OPTIMIZACIÓN DE PARÁMETROS DE PERFORACIÓN CON MSE E IMPACTO EN LA CONSTRUCCIÓN DE UN POZO EN EL CAMPO YARIGUÍ – CANTAGALLO

RESUMENEste trabajo contiene la información, seguimiento y análisis del mapa de parámetros y de datos de MSE (Energía  Mecánica Específica), durante la perforación de un pozo en tiempo record del campo Yariguí a partir de la metodología propuesta en el Instituto Colombiano del Petróleo (ICP) [1] en la cual se evalúa la relación de la  energía suministrada durante la perforación del pozo contra las propiedades geomecánicas de las formaciones  atravesadas, para determinar los parámetros óptimos que inciden la tasa de penetración.La metodología MSE se enmarca en la optimización de la perforación de pozos, buscando la disminución de tiempos y en consecuencia costos operacionales a partir de la evaluación y optimización de los parámetros de perforación en tiempo real garantizando un mejor desempeño durante la perforación. La evaluación en tiempo real se presenta como una respuesta y solución a los retos y las necesidades actuales de la industria donde cada día se no solo la visualización en Tiempo Real de todo el proceso de la perforación sino aumentar la eficiencia en la misma. La metodología MSE en tiempo real permite evaluar en una sola vista la eficiencia [6] y la estabilidad  de la energía consumida como respuesta a la combinación de los parámetros de perforación identificando tiempos invisibles y oportunidades de mejora. En este orden de ideas y después de tener disponible en las unidades de mudlogging el registro del parámetro MSE se decidió implementar un piloto de seguimiento en campo con el objetivo de realizar un análisis en tiempo real de los parámetros de perforación mediante la información entregada por la cabina de geología, realizando pruebas de perforabilidad, estableciendo la sensibilidad de los parámetros y entregando recomendaciones pertinentes y oportunas en campo. El seguimiento en tiempo real permite la interacción del personal involucrado en la operación en diferentes disciplinas, lo cual representa un valor agregado bajo todo punto de vista en especial el espacio de discusión y retroalimentación, lo que genera decisiones técnicamente más agiles, acertadas y concertadas traducidas en mejores y más satisfactorios resultados, asegurando además las mejores prácticas, el trabajo en equipo y el mejoramiento continuo. Palabras claves: Perforación, energía mecánica, geomecánica. OPTIMIZATION OF PARAMETERS OF DRILLING WITH MSE AND IMPACT ON THE CONSTRUCTION OF A WELL IN THE FIELD YARIGUI – CANTAGALLOABSTRACTThis paper contains monitoring information, and analysis of drilling parameters based on Mechanical Specific Energy log taken while drilling the record well in Yariguí field as from the methodology proposed in the Colombian Petroleum Institute (ICP) [1] where the relation between the energy provided and the geomechanical properties of the formations penetrated is evaluated on site while drilling by determining optimal parameters affecting the penetration rate The MSE methodology is frame in the drilling optimization strategy, looking for time reduction and operational costs based on real time evaluation and optimization of drilling parameters to ensure improved performance while drilling. The real time evaluation appears as a solution to the current challenges of the industry, where each day not just required the Real Time visualization of the drilling process but also increase their efficiency. The MSE methodology allows evaluating in a single view efficiency and stability of drilling parameter combination as function of the energy expended to identify invisible time and improvement opportunities. [6]Accordingly and after getting available MSE log and drilling parameters was decided to implement a pilot program to follow on site and building a real-time drilling parameters analysis using the mudlogging data and drill off tests to know the parameter sensitivity and providing pertinent and timely recommendations.The real time monitoring allows the interaction between all staff involved, representing an added value in every possible way especially the discussion and feedback opportunity, creating accurate and concerted decisions translated into better and more satisfactory results, while also ensuring best practices, teamwork and continuous improvement. Keywords: Drilling, mechanical energy

Racial/ethnic differences in hepatic steatosis in a population‐based cohort of post‐menopausal women: the Michigan Study of Women's Health Across the Nation

Aims The prevalence of hepatic steatosis may differ between post‐menopausal African‐American women and non‐Hispanic white women and by sex hormone binding globulin level. We examined prevalence of hepatic steatosis by race/ethnicity and associations with sex hormone binding globulin. Methods Participants included post‐menopausal women who underwent hepatic ultrasound ( n  = 345) at the Michigan site of the Study of Women's Health Across the Nation, a population‐based study. We examined hepatic steatosis prevalence by race/ethnicity and used logistic regression models to calculate the odds of hepatic steatosis with race/ethnicity and sex hormone binding globulin, after adjustment for age, alcohol use, waist circumference, high density lipoprotein cholesterol, triglycerides, systolic blood pressure and use of medications reported to lower intrahepatic fat. Results Fewer African‐American women than non‐Hispanic white women had hepatic steatosis (23 vs. 36%, P  = 0.01). African‐American women had lower triglyceride and low‐density lipoprotein cholesterol levels, but higher blood pressure and follicle‐stimulating hormone levels ( P  < 0.05). In the optimal‐fitting multivariable models, women in the highest tertile of sex hormone binding globulin (60.2–220.3 nmol/l) had a lower odds of hepatic steatosis (odds ratio 0.43, 95% CI 0.20–0.93) compared with women in the lowest tertile of sex hormone binding globulin (10.5–40.3 nmol/l). There was an interaction between race/ethnicity and medication use whereby non‐Hispanic white women using medications had three times higher odds of hepatic steatosis compared with African‐American women not using medications (odds ratio 3.36, 95%  CI 1.07–10.58). Interactions between race/ethnicity and other variables, including sex hormone levels, were not significant. Conclusions Hepatic steatosis on ultrasound may be more common in post‐menopausal non‐Hispanic white women than African‐American women and was associated with lower levels of sex hormone binding globulin. What's new? Although hepatic steatosis is common in post‐menopausal women, previous studies have not examined risk factors in this population, particularly sex steroids and sex hormone binding globulin. We report that increased sex hormone binding globulin, the primary binding protein of sex hormones and a risk factor for diabetes, was strongly associated with decreased odds of hepatic steatosis in both race/ethnicities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/101792/1/dme12225.pd

Pilot study on the prevalence of salmonella in slaughter pigs in Germany: III. Detection of salmonellae by PCR, serovar distribution and population analysis of isolates

In a survey on the prevalence of Salmonellae in German slaughter pigs, almost 12,000 pig carcasses were investigated by standard cultural, immunological and PCR technique\u27s. Seven abattoirs distributed all over Germany were included into the study. Each abattoir was investigated on ten weekly sampling occasions. In total 6% of all slaughter pigs were positive in faecal or lymphnode material. This number increased to I 0% when surface swabs were evaluated as well. From all sources nearly 1400 bacterial isolates were obtained and characterised by traditional and molecular typing methods. Typing at the National Reference Laboratory for Salmonella (NRL) follows a hierarchic protocol. At the beginning the serotype is determined by using poly- and monoclonal antisera for standard slide agglutination. In total 28 serotypes could be detected

Pilot study on the prevalence of salmonella in slaughter pigs in Germany: IV. Field experiences using the Danish serological method for detection

In an interlaboratory study on the prevalence of Salmonellae in German slaughter pigs a comparison of the traditional bacteriological and the serological technique used in the Danish Salmonella control programme was included. In total, about 12000 animals were investigated using both techniques. Samples were collected from February through June 1996. Seven slaughterhouses distributed over the whole country participated on a voluntary basis. A total of 11,942 animals delivered in 752 lots at ten occasions to the participating slaughterhouses were investigated. The lots often comprised pigs from individual finishing farms. From each lot, a maximum of 50 animals were sampled. A faecal swab, a mesenteric lymph node and a meat sample were collected from each carcass. The results of the microbiological analysis of faeces and lymph nodes of each animal were described in separate presentations

Association of Salmonella spp. in slaughter pigs with farm management factors

The objective of the study was to investigate the assoctatwn of farm management factors with the detection of Salmonella in lymph nodes of pigs at slaughter. Samples were collected in German abattoirs in the course of the EU baseline study on Salmonella in slaughter pigs from October 2006 to September 2007. A minimum of 5 lymph nodes (\u3e15 g sample weight) were collected from pigs at slaughter and examined for Salmonella according to IS06579:2003, Annex D. Data were collected using a standardized data capture form to be filled in by the veterinary officials. Additional information was available in a subsample (85112569) of the pigs included in that study. The association of factors was tested using univariate and multivariate logistic regression. Separate analyses were run for a: Salmonella spp., b: specifically for S. Typhimurium, the most prevalent Salmonella serovar in the study population and c: for all other serovars grouped together