The maximum of the local time of a diffusion process in a drifted Brownian potential

We consider a one-dimensional diffusion process $X$ in a $(-\kappa/2)$-drifted Brownian potential for $\kappa\neq 0$. We are interested in the maximum of its local time, and study its almost sure asymptotic behaviour, which is proved to be different from the behaviour of the maximum local time of the transient random walk in random environment. We also obtain the convergence in law of the maximum local time of $X$ under the annealed law after suitable renormalization when $\kappa \geq 1$. Moreover, we characterize all the upper and lower classes for the hitting times of $X$, in the sense of Paul L\'evy, and provide laws of the iterated logarithm for the diffusion $X$ itself. To this aim, we use annealed technics.Comment: 38 pages, new version, merged with hal-00013040 (arXiv:math/0511053), with some additional result

Uloga testova otpuštanja interferona gama u nadzoru nad tuberkulozom

Tuberculosis is still one of the major global public health threats. Countries with low incidence must focus on exhausting the reservoir of future cases by preventing reactivation. Therefore, it is important to identify and effectively treat those individuals who have latent tuberculosis infection and who may develop active disease. The tuberculin skin test has been the standard for detection of immune response against M. tuberculosis since the beginning of the 20th century. The new millennium has brought advancement in the diagnosis of latent tuberculosis infection. The name of the new blood test is interferon-gamma release assay (IGRA). Croatia is a middle-incidence country with a long decreasing trend and developed tuberculosis control. To reach low incidence and finally eliminate tuberculosis, its tuberculosis programme needs a more aggressive approach that would include intensive contact investigation and treatment of persons with latent tuberculosis infection. This article discusses the current uses of IGRA and its role in tuberculosis control.Tuberkuloza je i danas jedan od vodećih javnozdravstvenih problema. Zemlje s niskom incidencijom fokusiraju se na iscrpljivanje rezervoara budućih slučajeva sprječavanjem reaktivacije bolesti. To se odnosi na traženje i učinkovito liječenje infi ciranih osoba, primarno onih koje su u riziku od obolijevanja nakon infekcije. Tuberkulinski test je od početka 20. stoljeća bio standard u otkrivanju imunosnog odgovora na kontakt s Mycobacterium tuberculosis. Novo tisućljeće donijelo je određeni napredak u obliku novih testova za dijagnozu latentne tuberkulozne infekcije, krvne testove otpuštanja interferona gama. Hrvatska je zemlja srednje incidencije tuberkuloze s dugogodišnjim silaznim trendom i razvijenim protutuberkuloznim aktivnostima. U težnji prema niskoj incidenciji i u konačnici eliminaciji tuberkuloze potrebne su opsežnije aktivnosti unutar državnog programa nadzora nad tuberkulozom, uključujući intenzivnu obradu kontakata i probir na postojanje latentne tuberkulozne infekcije. Ovaj rad razmatra trenutačnu uporabu IGRE (engl. interferon - gamma release assay) i njezinu ulogu u nadzoru nad tuberkulozom

Screening for latent tuberculosis infection among undocumented immigrants in Swiss healthcare centres; a descriptive exploratory study

BACKGROUND: Migration is one of the major causes of tuberculosis in developed countries. Undocumented patients are usually not screened at the border and are not covered by a health insurance increasing their risk of developing the disease unnoticed. Urban health centres could help identify this population at risk. The objective of this study is to assess the prevalence of latent tuberculosis infection (LTBI) and adherence to preventive treatment in a population of undocumented immigrant patients. METHODS: All consecutive undocumented patients that visited two urban healthcare centres for vulnerable populations in Lausanne, Switzerland for the first time were offered tuberculosis screening with an interferon-gamma assay. Preventive treatment was offered if indicated. Adherence to treatment was evaluated monthly over a nine month period. RESULTS: Of the 161 participants, 131 (81.4%) agreed to screening and 125 had complete examinations. Twenty-four of the 125 patients (19.2%; CI95% 12.7;27.2) had positive interferon-gamma assay results, two of which had active tuberculosis. Only five patients with LTBI completed full preventive treatments. Five others initiated the treatment but did not follow through. CONCLUSION: Screening for tuberculosis infection in this hard-to-reach population is feasible in dedicated urban clinics, and the prevalence of LTBI is high in this vulnerable population. However, the low adherence to treatment is an important public health concern, and new strategies are needed to address this problem

Estoques de carbono lábil e total em solo sob integração lavoura-pecuária-floresta na região de Transição Cerrado/Amazônia.

Objetivou-se comparar o sistema de integração lavoura-pecuária-floresta com sistemas exclusivos quanto à assimilação e manutenção do carbono orgânico total (COT) e carbono lábil (CL), após o segundo ano de estabelecimento. Os tratamentos constituíram os seguintes sistemas de produção: floresta de eucalipto (EUC), pastagem com Brachiaria brizantha (PAST), lavoura de soja-milho consorciada com B. brizantha (LAV) e integração lavoura-pecuária-floresta (ILPF). Uma área de fragmento florestal nativo (Mata) e uma de pousio (Pousio) foram utilizadas como referência. A área sob cultivo de EUC obteve o menor teor de COT na camada 0-5cm, enquanto LAV e PAST apresentaram os maiores teores. Por sua vez, os teores de COT para o sistema ILPF, na camada 0-5cm, ficou em uma posição intermediária aos demais. A conversão da vegetação nativa para em cultivo agrícola e florestal contribuiu para a redução dos estoques de COT no solo em 20% na camada de 0-30 cm, representando uma perda de 17,4 Mg ha-1. O efeito do componente florestal na distribuição horizontal do estoque de COT dentro do ILPF foi favorecido no sentido sul, tendência não verificada para CL. Em curto prazo, os impactos dos sistemas conservacionistas sobre os teores de COT e CL do solo foram identificados apenas na camada superficial

Quantum quenches in the anisotropic spin-1/2 Heisenberg chain: different approaches to many-body dynamics far from equilibrium

Recent experimental achievements in controlling ultracold gases in optical lattices open a new perspective on quantum many-body physics. In these experimental setups it is possible to study coherent time evolution of isolated quantum systems. These dynamics reveal new physics beyond the low-energy properties usually relevant in solid-state many-body systems. In this paper we study the time evolution of antiferromagnetic order in the Heisenberg chain after a sudden change of the anisotropy parameter, using various numerical and analytical methods. As a generic result we find that the order parameter, which can show oscillatory or non-oscillatory dynamics, decays exponentially except for the effectively non-interacting case of the XX limit. For weakly ordered initial states we also find evidence for an algebraic correction to the exponential law. The study is based on numerical simulations using a numerical matrix product method for infinite system sizes (iMPS), for which we provide a detailed description and an error analysis. Additionally, we investigate in detail the exactly solvable XX limit. These results are compared to approximative analytical approaches including an effective description by the XZ-model as well as by mean-field, Luttinger-liquid and sine-Gordon theories. This reveals which aspects of non-equilibrium dynamics can as in equilibrium be described by low-energy theories and which are the novel phenomena specific to quantum quench dynamics. The relevance of the energetically high part of the spectrum is illustrated by means of a full numerical diagonalization of the Hamiltonian.Comment: 28 page