Study of CMS sensitivity to neutrinoless τ\tau decay at LHC

The Large Hadron Collider (LHC), scheduled to start operation in 2006, is foreseen to provide in the first year of running a total of $\sim 10^{12}$ $\tau$ leptons. CMS (Compact Muon Solenoid) is a general-purpose experiment designed to study proton-proton and heavy-ion collisions at LHC. Even if the Susy particles and Higgs searches togheter with the B-physics present its main goal, the large amount of $\tau$-lepton, could allow a systematic study of tau-physics. We have performed a full simulation of CMS using GEANT 3 package and the object-oriented reconstruction program ORCA to study the sensitivity to neutrinoless tau decay $\tau \to \mu^+ \mu^- \mu^-$ and $\tau \to \mu \gamma$. We present the analysis developed for these channels and the results obtained.Comment: Invited talk at the seventh international Workshop on tau lepton physics (TAU02), Santa Cruz, Ca, Usa, September 2002 10 pages 15 eps figure

Toward Contention Analysis for Parallel Executing Real-Time Tasks

In measurement-based probabilistic timing analysis, the execution conditions imposed to tasks as measurement scenarios, have a strong impact to the worst-case execution time estimates. The scenarios and their effects on the task execution behavior have to be deeply investigated. The aim has to be to identify and to guarantee the scenarios that lead to the maximum measurements, i.e. the worst-case scenarios, and use them to assure the worst-case execution time estimates. We propose a contention analysis in order to identify the worst contentions that a task can suffer from concurrent executions. The work focuses on the interferences on shared resources (cache memories and memory buses) from parallel executions in multi-core real-time systems. Our approach consists of searching for possible task contenders for parallel executions, modeling their contentiousness, and classifying the measurement scenarios accordingly. We identify the most contentious ones and their worst-case effects on task execution times. The measurement-based probabilistic timing analysis is then used to verify the analysis proposed, qualify the scenarios with contentiousness, and compare them. A parallel execution simulator for multi-core real-time system is developed and used for validating our framework. The framework applies heuristics and assumptions that simplify the system behavior. It represents a first step for developing a complete approach which would be able to guarantee the worst-case behavior

The Old Bridle Path: It Is Solved by Walking

A member of the Greenleaf Hut crew, or “croo,” below the summit of Mount Lafayette in the White Mountains of New Hampshire connects to the natural history of the mountain through frequent foot trips on the Old Bridle Path

Progetto, realizzazione e validazione sperimentale di un'applicazione SDN per Traffic Recovery e Load Balancing

Nel corso degli ultimi anni, la comunità scientifica si è prodigata nell'esplorazione delle potenzialità fornite dal Software-Defined Networking, un paradigma che prevede la netta separazione tra piano dati e piano di controllo all'interno di una rete. Così facendo, il comportamento dei dispositivi risulta programmabile tramite un'applicazione di controllo. In questo contesto, il presente elaborato documenta il lavoro di tesi intrapreso per progettare, realizzare e validare una tale applicazione avente funzionalità di Traffic Recovery e Load Balancing. Le stime riguardanti l'utilizzazione dei collegamenti e la banda occupata dai vari flussi, così come la rivelazione dei malfunzionamenti, sono state gestite sfruttando le peculiarità del protocollo OpenFlow. L'aspetto relativo alla Traffic Recovery è stato affrontato con strategie sia reattive che proattive. In particolare, il traffico generato dalle sorgenti può essere suddiviso in quattro classi, caratterizzate da un livello di protezione via via crescente. Riguardo alla funzionalità di Load Balancing, sono state adottate e confontate tre possibili metriche per l'assegnazione dei costi ai vari collegamenti, in funzione del carico da essi sperimentato. During the last years, Software-Defined Networking (SDN) has been widely explored in order to understand the possibilities provided by this kind of architecture. Introducing a clean separation between the control plane and the data plane within the network, SDN allows a control application to program the behavior of the underlying infrastructure. This thesis deals with designing, fulfilling and validating such an application with Traffic Recovery and Load Balancing tasks. The features of the OpenFlow protocol have been exploited in order to provide an estimate of links utilization and flows bandwidth, as well as to effectively detect link failures. Traffic Recovery has been handled adopting both reactive and proactive strategies. More precisely, network traffic can be grouped into four classes with an increasing level of protection. With respect to Load Balancing, three alternative ways of assigning a cost to a certain link, as a function of its load, have been defined and compared

Mucosal microenvironment and host immunity in HPV-driven carcinogenesis

Background: Innate immunity pathways, especially those related to type I and III interferon (IFN) are involved in Human Papillomavirus (HPV) recognition and clearance. Among HIV-1 positive men who have sex with men (MSM), the extremely high incidence of HPV infection is strongly associated with an increased risk of squamous cell carcinoma of the anal canal. To date, few data are available on the complex interplay between persistent mucosal HPV infection, IFN signature, and their involvement in cancer development. At the same time, NK cells mediated cytotoxicity plays a pivotal role in mucosal response against HPV infection and dysplasia, but their activity is counteracted by several HPVs. We hypothesized that HPV, through evasion strategies adopted to overcome the host immune defense, might modulate levels of different type I and III IFN genes, as well as of NK cells in the anal mucosa of HIV-1 MSM patients. Moreover, a goal of this project is to evaluate the effects of oral bacteriotherapy supplementation on anal IFN transcript levels, the frequencies of intra-epithelial NK cell subsets and on immune activation status of HPV-HIV-1 infected MSM. Methods: Anal brushings were collected from 110 Caucasian HIV-1 infected MSM, with a median age of 47.4 (41–52.75) years, on long-term antiretroviral therapy (ART), attending Policlinico Umberto I Hospital in Rome. Detection of HPV DNA and genotyping were performed by PCR and sequencing. The mRNA levels of IFN-α, IFN-β, IFN-ε, an emerging component of innate immune defence at mucosal sites, IFNAR1 and IFNAR2 receptors, IFN-λ 1-3 subtypes and IL28R receptor, were measured in anal brushings by TaqMan RT–PCR. A subgroup of HPV-HIV-1 co-infected MSM underwent high resolution anoscopy (HRA), to obtain biopsies from areas consistent with SIL and healthy mucosa. Intra-Epithelial Lymphocytes (IELs) were isolated from anal biopsies and stained to identify CD56+, CD16+, CD56dim, CD56bright NK cells and NKT cells by multiparametric flow cytometry. In addition, type I and III IFN levels, NK cell subsets and the frequencies of CD4+ and CD8+ T lymphocytes expressing CD38 and HLADR were evaluated after six months of oral bacteriotherapy supplementation. Results: Anal HPV DNA was detected in 87 MSM patients (79%), with 49.4% of the cases having a high-risk (HR) HPV genotype, mainly HPV16. Out of 110 patients, 58.4% showed HSIL/LSIL. A decreased mucosal expression of IFN-β, IFN-ε, IFNAR1 and IFNAR2 as well as IFN-λ 1-3 was recorded in HR compared to low-risk (LR) HPV positive and HPV negative patients (Mann-Whitney U test p <0.05 for all genes). No differences were found on levels of type I and III components according to the presence or absence of SIL. By contrast, the expression of IFN-β, IFN-ε, IFNAR1, IFNAR2 and IFN-λ 1-3 was reduced in patients with a persistent HPV infection compared to those who spontaneously cleared the infection (Mann-Whitney U test p <0.01 for all genes). A reduction in the frequencies of CD16+ NK cells was found in the dysplastic mucosa (LSIL) as compared to the normal anal mucosa, while the levels of CD56+, CD56dim, CD56bright NK cells and NKT cells were similar between LSIL and normal anal mucosa of HPV positive patients. Oral bacteriotherapy supplementation resulted in changes in IFN-I and III levels and in frequency of peripheral CD38/HLA-DR T cell subsets evaluated by flow cytometry (p<0.05 for all variables). Moreover, an increase of CD16+ NK and NKT cell frequencies and a trend toward an upregulation of CD56+ NK cells (p=0.089) has been observed after probiotic intake. Interestingly, oral bacteriotherapy induce also the clearance of HPV anal lesions in one HR-HPV infected MSM. Conclusions: HPV persistent infection is able to regulate type I and III IFN and NK cells responses response and contribute to the establishment of an immunosuppressive microenvironment in mucosal epithelia, which is essential for precancerous anal lesions progression. Moreover, results suggest a potential role for oral probiotic supplementation in modulating mucosal immunity and promoting the regression of anal HPV related lesions in HIV-1 infected MSM