Combination of Loop-Mediated Isothermal Amplification Assay and Nested PCR for Detection of Borrelia burgdorferi sensu lato in Human Serum Samples

A set of universal loop-mediated isothermal amplification （LAMP） primers targeting the flo gene was designed to detect Borrelia burgdorferi sensu lato （B. burgdorferi s.I.） in human samples. The sensitivity of LAMP was 20 copies/reaction, and the assay did not detect false positives among 11 other related bacteria. A positive LAMP result was obtained for 9 of the 24 confirmed cases and for 12 of 94 suspected cases. The positive rate of LAMP was the same as that of nested PCR. The LAMP is a useful diagnostic method that can be developed for rapid detection of B. burgdorferi s.I. in human sera. Combination of the LAMP and nested PCR was more sensitive for detecting B. burgdorferi s.I. in human serum samples.

Event-Based Semantics of UML 2.X Concurrent Sequence Diagrams for Formal Verification

UML 2.X sequence diagrams(SD)are among privileged scenarios-based approaches dealing with the complexity of modeling the behaviors of some current systems.However,there are several issues related to the standard semantics of UML 2.X SD proposed by the Object Management Group(OMG).They mainly concern ambiguities of the interpretation of SDs,and the computation of causal relations between events which is not specifically laid out.Moreover,SD is a semi-formal language,and it does not support the verification of the modeled system.This justifies the considerable number of research studies intending to define formal semantics of UML SDs.We proposed in our previous work semantics covering the most popular combined fragments(CF)of control-flow ALT,OPT,LOOP and SEQ,allowing to model alternative,optional,iterative and sequential behaviors respectively.The proposed semantics is based on partial order theory relations that permit the computation of the precedence relations between the events of an SD with nested CFs.We also addressed the issue of the evaluation of the interaction constraint(guard)for guarded CFs,and the related synchronization issue.In this paper,we first extend our semantics,proposed in our previous work;indeed,we propose new rules for the computation of causal relations for SD with PAR and STRICT CFs(dedicated to modeling concurrent and strict behaviors respectively)as well as their nesting.Then,we propose a transformational semantics in Event-B.Our modeling approach emphasizes computation of causal relations,guard handling and transformational semantics into Event-B.The transformation of UML 2.X SD into the formal method Event-B allows us to perform several kinds of verification including simulation,trace acceptance,verification of properties,and verification of refinement relation between SDs.

Implementation of a new network equilibrium model of travel choices

This paper develops a new combined network equilibrium model by using more behaviorally sound mathematical forms to represent the four travel choices（i.e., trip frequency,destination, mode, and route） in a conventional travel demand forecasting process. Trip frequency choice relates to the traveler decision on “making a trip” or “not making a trip”so it is given by a binary logit model. Destination choice is formulated as a parameterized dogit model of which the captivity parameters（expressed as functions of independent variables） allow individual travelers to be captive to specific destinations. Mode choice is given by a two-level nested logit model to avoid IIA restriction. Trip assignment is based on Wardrop＇s “user-optimized” principle. All model forms describing travel choices are in response to the level of services incurred by the transportation system. Through the introduction of inclusive values, the traveler decisions concerning trip frequency, destination, mode, and route choices are inherently interrelated and jointly determined.To obtain solutions of the new combined model, it was reformulated as an equivalent convex programming problem with linear constraints, a great advantage from the computational aspects. The model was applied empirically to a transportation network in New Jersey. The application results show that the new model is consistently better than the commonly used logit combined model in reproducing the observed trip flows from origin zones, origin to destination（O-D） trip flows, O-D trip flows by mode, and trip flows on the network links.