Hamiltonian model of heat conductivity and Fourier law

We investigate the stationary nonequilibrium states of a quasi one-dimensional system of heavy particles whose interaction is mediated by purely elastic collisions with light particles, in contact at the boundary with two heat baths with fixed temperatures $T^+$ and $T^-$. It is shown that Fourier law is satisfied with a thermal conductivity proportional to $\sqrt{T(x)}$ where $T(x)$ is the local temperature. Entropy flux and entropy production are also investigated.Comment: 12 pages, 4 figure

On the Second Law of thermodynamics and the piston problem

The piston problem is investigated in the case where the length of the cylinder is infinite (on both sides) and the ratio $m/M$ is a very small parameter, where $m$ is the mass of one particle of the gaz and $M$ is the mass of the piston. Introducing initial conditions such that the stochastic motion of the piston remains in the average at the origin (no drift), it is shown that the time evolution of the fluids, analytically derived from Liouville equation, agrees with the Second Law of thermodynamics. We thus have a non equilibrium microscopical model whose evolution can be explicitly shown to obey the two laws of thermodynamics.Comment: 29 pages, 9 figures submitted to Journal of Statistical Physics (2003

Relapse prevention for addictive behaviors

The Relapse Prevention (RP) model has been a mainstay of addictions theory and treatment since its introduction three decades ago. This paper provides an overview and update of RP for addictive behaviors with a focus on developments over the last decade (2000-2010). Major treatment outcome studies and meta-analyses are summarized, as are selected empirical findings relevant to the tenets of the RP model. Notable advances in RP in the last decade include the introduction of a reformulated cognitive-behavioral model of relapse, the application of advanced statistical methods to model relapse in large randomized trials, and the development of mindfulness-based relapse prevention. We also review the emergent literature on genetic correlates of relapse following pharmacological and behavioral treatments. The continued influence of RP is evidenced by its integration in most cognitive-behavioral substance use interventions. However, the tendency to subsume RP within other treatment modalities has posed a barrier to systematic evaluation of the RP model. Overall, RP remains an influential cognitive-behavioral framework that can inform both theoretical and clinical approaches to understanding and facilitating behavior change

Development of the CMS tracker and reconstruction of secondary vertices of B- and C-hadrons

In this dissertation the performance of the CMS experiment to reconstruct secondary vertices originating from b- and c-hadrons has been investigated. CMS is one of the four detectors at the Large Hadron Collider (LHC) at CERN. The physical properties of vertices and the vertex reconstruction algorithms are shown. The performance of the vertex reconstruction and of the identification of b-jets (b-tagging) are investigated. It is shown that the performance of a vertex algorithm, developed in the context of this thesis, is higher than that of the CMS standard algorithm. The CMS tracker is the most important detector component for the vertex reconstruction. Two probe stations for the quality assurance of silicon strip sensors have been designed and constructed within this dissertation

Inclusive Secondary Vertex Reconstruction in Jets

Inclusive secondary vertex reconstruction in jets in the CMS detector at the LHC is described. The perfomance of the algorithms is studied in terms of vertex finding efficiency, purity, resolution and other quantities. The dependence on the kinematics is also studied as well as the effects of an imperfectly aligned tracking detector

The use of micro–computed tomography to determine the accuracy of 2 electronic apex locators and anatomic variations affecting their precision

Introduction The aim of this study was to compare the accuracy of 2 electronic apex locators (EALs), Apex ID (SybronEndo, Glendora, CA) and Root ZX (J. Morita, Tokyo, Japan), by means of micro–computed tomographic (micro-CT) imaging and to determine anatomic variations that may affect their accuracy. Methods The root canal length (RCL) and working length (WL) of 33 single-rooted premolars were measured using a visual method, 3-dimensional micro-CT reconstructions, and 2 different EALs. Two different measurements were recorded for each EAL: at the “APEX/0.0” mark and at the “0.5” mark. The WL was determined using 2 different methods: method 1: at the “0.5 mark” of the apex locator and method 2: subtracting 0.5 mm from the “APEX/0.0” mark. The precision of measurements was compared with those recorded by micro-CT imaging. Apical foramen (AF) position and diameter, apical constriction (AC) diameter, distance between the AC and the AF, and the presence/absence of accessory canals were recorded from the micro-CT scans, and their correlation to the accuracy of EALs was determined. Results There was no statistically significant difference in the RCL measurements by any of the different methods. There was a statistically significant difference in the WL recorded by micro-CT imaging compared with those by the visual method and at the “APEX/0.0 mark” − 0.5 mm (P = .031). There was no difference in the measurements acquired by any of the EALs. The “APEX/0.0 mark” − 0.5 mm was less accurate than the “0.5” mark. However, the results were not statistically significant (P > .05). The position of the AF and the AC–AF distance affected the accuracy of the RCL (P = .003) and the “0.5” mark (P = .013). Conclusions Root ZX and Apex ID are equally precise in determining the RCL and WL. The “0.5” mark can be used to determine the WL with high precision. Some anatomic variations may influence the accuracy of EALs

Mechanical resistance of carbon and stainless steel hand instruments used in a reciprocating handpiece

The manual files are still widely used for initial canal negotiation prior the use of nickel-titani-um shaping instruments, to determine working length and to verify patency. A mechanical glide path can be performed using manual files with handpieces, such as M4 Handpiece (SybronEndo, USA) that allows a 30°/30° reciprocating motion. The Pathfinders (SybronEndo, USA) are hand files designed to negotiate complex canals, made from stainless steel (SS) or carbon steel (CS) alloys. The aim of this in vitro study was to compare cyclic fatigue resistance of these two different types of manual Pathfinder instruments used in a M4 reciprocating handpiece in double curved artificial canals. Manual instruments designed for glide path (size #9 ISO .02 taper) made from different alloys were selected: Group SS - stainless steel Pathfinders (Sybron Endo) and Group CS - carbon steel Pathfinders size K2 (Sybron Endo). Ten instruments of each group were tested for resistance to cyclic fatigue with a reciprocating M4 handpiece inside an artificial S-shaped canal; the time to fracture was recorded for each file and data were statistically analyzed (ANOVA). Mean values (and SD) were 527 (± 89) seconds for the CS instruments and 548 (± 104) seconds for the SS files. No significant differences were observed between groups (p=0,062). According to the results, both carbon and stainless steel instruments presented similar fatigue resistance when used with M4 reciprocating handpiece in double curved canals