4 research outputs found
Analysis of stability and density waves of traffic flow model in an ITS environment
By introducing relative velocities of arbitrary number of cars ahead into the full velocity difference models (FVDM), we present a forward looking relative velocity model (FLRVM) of cooperative driving control system. To our knowledge, the model is an improvement over the similar extension in the forward looking optimal velocity models (FLOVM), because it is more reasonable and realistic in implement of incorporating intelligent transportation system in traffic. Then the stability criterion is investigated by the linear stability analysis with finding that new consideration theoretically lead to the improvement of the stability of traffic flow, and the validity of our theoretical analysis is confirmed by direct simulations. In addition, nonlinear analysis of the model shows that the three waves: triangular shock wave, soliton wave and kink-antikink wave appear respectively in stable, metastable and unstable regions. These correspond to the solutions of the Burgers equation, Korteweg-de Vries (KdV) equation and modified Korteweg-de Vries (mKdV) equation. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200689.40.-a Transportation, 64.60.Cn Order-disorder transformations; statistical mechanics of modelsystems, 02.60.Cb Numerical simulation; solution of equations, 05.70.Fh Phase transitions: general studies,
Behavioural characteristics, prevalence of Chlamydia trachomatis and antibiotic susceptibility of Neisseria gonorrhoeae in men with urethral discharge in Thyolo, Malawi.
A study was carried out in 2000/2001 in a rural district of Malawi among men presenting with urethral discharge, in order to (a) describe their health-seeking and sexual behaviour, (b) determine the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis, and (c) verify the antibiotic susceptibility of N. gonorrhoeae. A total of 114 patients were entered into the study; 61% reported having taken some form of medication before coming to the sexually transmitted infections clinic. The most frequent alternative source of care was traditional healers. Sixty-eight (60%) patients reported sexual encounters during the symptomatic period, the majority (84%) not using condoms. Using ligase chain reaction on urine, N. gonorrhoeae was detected in 91 (80%) and C. trachomatis in 2 (2%) urine specimens. Forty five of 47 N. gonorrhoeae isolates produced penicillinase, 89% showing multi-antimicrobial resistance. This study emphasizes the need to integrate alternative care providers and particularly traditional healers in control activities, and to encourage their role in promoting safer sexual behaviour. In patients presenting with urethral discharge in our rural setting, C. trachomatis was not found to be a major pathogen. Antimicrobial susceptibility surveillance of N. gonorrhoeae is essential in order to prevent treatment failures and control the spread of resistant strains
Changes in Escherichia coli resistance to co-trimoxazole in tuberculosis patients and in relation to co-trimoxazole prophylaxis in Thyolo, Malawi.
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out in 1999 and 2001 to determine (i) whether faecal Escherichia coli resistance to co-trimoxazole in TB patients changed with time, and (ii) whether the resistance pattern was different in HIV-positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E. coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (P < 0.01). Resistance was 89% among HIV-infected TB patients (receiving cotrimoxazole), while in HIV-negative patients (receiving anti-TB therapy alone) it was 62% (P < 0.001). The study shows a significant increase of E. coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV-infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E. coli and the Salmonella species, these findings could herald limitations on the short- and long-term benefits to be expected from the use of co-trimoxazole prophylaxis in preventing non-typhoid Salmonella bacteraemia and enteritis in HIV-infected TB patients in Malawi
Changes in Escherichia coli resistance to co-trimoxazole in tuberculosis patients and in relation to co-trimoxazole prophylaxis in Thyolo, Malawi.
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out in 1999 and 2001 to determine (i) whether faecal Escherichia coli resistance to co-trimoxazole in TB patients changed with time, and (ii) whether the resistance pattern was different in HIV-positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E. coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (P < 0.01). Resistance was 89% among HIV-infected TB patients (receiving cotrimoxazole), while in HIV-negative patients (receiving anti-TB therapy alone) it was 62% (P < 0.001). The study shows a significant increase of E. coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV-infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E. coli and the Salmonella species, these findings could herald limitations on the short- and long-term benefits to be expected from the use of co-trimoxazole prophylaxis in preventing non-typhoid Salmonella bacteraemia and enteritis in HIV-infected TB patients in Malawi