Optical and electrooptical analysis of GaAs inverted rib phase modulators grown by vapor phase epitaxy

We present experimental and theoretical analysis of GaAs homojunction Schottky barrier phase modulators. The waveguide structures-inverted rib-were grown using the vapor-phase-epitaxy chloride process. These structures are attractive because perfectly planar devices can be realized. Besides that, single-mode operation and low losses can be achieved. The optical (propagation losses, dispersion curves), electrical (electrical field distribution, breakdown voltages) and electrooptical (modulation efficiency) parameters have been calculated using numerical two-dimensional methods. In order to optimize the modulator, various waveguide structures as well as n+ (i.e., substrate) and n- (i.e., waveguide) dopings have been considered in the modeling. Experimental results fit well with the calculated ones. A modulation efficiency of 2.3° . V^-1. mm^-1has been measured. For a completely optimized structure, an efficiency of 4° . V^-1. mm^-1is expected.     

Quantification of lycopene in tomato products: comparing the performances of a newly proposed direct photothermal method and high‐performance liquid chromatography

A new photothermal method suitable for direct, accurate and highly reproducible quantitative measurements of lycopene in tomato products has been introduced. The intrinsic precision of the method is typically better than 0.2%; the repeatability of determination is comparable to that of high‐performance liquid chromatography, with 0.86% least overall error. Copyright © 2005 Society of Chemical Industry     

Membership function shape and the dynamic behaviour of fuzzy systems

In this paper the influence of the shape of the membership functions on the dynamic behaviour of a fuzzy controlled system is investigated. Although several works on fuzzy logic have been presented in the literature, few efforts have been made to characterize the dynamic behaviour of a fuzzy system through the shape of the membership functions. A parametrization for a class of membership functions is introduced in this work, resulting in a variety of shapes. Various system steady state dynamics are analysed as a consequence of this change in shape and chaotic dynamics is shown to arise for some membership function shapes.     

Heuristic and exact algorithms for the multi-pile vehicle routing problem

The multi-pile vehicle routing problem is a particular combination of loading and routing problems, in which items have to be loaded into different piles within vehicles, and then delivered with minimum cost. The problem is motivated by a real-world timber distribution problem, and is of both theoretical and practical interest. In this paper, we first develop heuristic and exact methods to solve the loading problem. We then include these methods into a tailored combination of Variable Neighborhood Search and Branch-and-Cut, to solve the overall problem. Extensive computational results show how the resulting algorithms are capable of solving to optimality a large number of small-size instances, and of consistently outperforming previous algorithms from the literature on large-size and real-world instances.     

Suspended and localized single nanostructure growth across a nanogap by an electric field

Direct growth of a suspended single nanostructure (SSN) at a specific location is presented. The SSN is grown across a metallic nanoscale gap by migration in air at room temperature. The nanogap is fabricated by industrial standard optical lithography and anisotropic wet chemical silicon etching. A DC current bias, 1 nA, is applied across the metallic gap to induce nanoscale migration of Zn or ZnO. The history of the voltage drop across the gap as a function of time clearly indicates the moment when migration begins. The shape of SSNs grown across the nanogap by the migration is asymmetric at each electrode due to the asymmetric electric field distribution within the nanogap. An SSN can be used as the platform for two-terminal active or passive nanoscale electronics in optoelectronics, radio frequency (RF) resonators, and chemical/biological sensors.     

Road network monitoring: algorithms and a case study

Road network monitoring is an activity conducted daily by the Ministry of Transportation of Quebec. The complete network must be monitored every 2 weeks. In this setting, the usual objective in arc routing of minimizing the total travel distance is irrelevant. The vehicles are equipped with global positioning systems (GPS) locating devices to monitor events and trace routes. Since most planned route are not completed because of events on the network, there is a need to continuously re-plan and re-schedule routes. We developed a methodology to achieve this task by gathering data from the GPS trace, matching it to the planned routes within a geographic information systems (GIS) and then use mathematical algorithms to propose a new schedule with new routes. The interurban road network studied consists in a hierarchy of three classes of roads that have different monitoring standards. We tested three different methods using different objectives depending on the operators’ needs. Results show that the method that implies rescheduling based on assignment and reconstruction of routes with an arc-adding method gives the best coverage for each class of road.     

Nail changes in patients infected with human immunodeficiency virus. A prospective controlled study

OBJECTIVES: To study the frequency of nail changes in a population of human immunodeficiency virus (HIV)-infected patients and to evaluate the specificity of these findings by comparison with HIV-negative control subjects. DESIGN: Prospective controlled study. Nail changes were recorded by a standardized clinical examination (curvature, nail plate, color, onychomycosis). In case of clinical diagnosis of onychomycosis, mycological culture was performed. SETTING: Primary care university hospital. PATIENTS: A total of 155 HIV-1-positive patients and 103 healthy HIV-negative control subjects of comparable age and sex ratio. INTERVENTION: None. MAIN OUTCOME MEASURE: Clinical examination findings. RESULTS: Nail symptoms were present in 67.7% of HIV-positive patients vs 34.0% of controls (P < .001). The following symptoms were significantly more frequent in the HIV group: clubbing (5.8%) (P < .05), transverse lines (7.1%) (P < .01), onychoschizia (7.1%) (P < .05), leukonychia (14.3%) (P < .001), and longitudinal melanonychia (14.8%) (P < .01). The main finding was onychomycosis in 30.3% of patients vs 12.6% of controls (P < .001). Trichophyton rubrum was present in 48% of onychomycoses and unusual Candida species were also recorded. Multiple fungi were frequently cultured in a single patient. The mean CD4+ cell count was lower in patients with onychomycosis and the frequency of onychomycosis increased in advanced stages of HIV disease. Acquired total leukonychia of the 20 nails was present in 4% of patients. CONCLUSION: Nail symptoms are much more frequent in patients with HIV than in healthy controls, and some of them could be linked to the level of immunosuppression.     

Hepatitis G virus infection in hemodialysis patients

The increased risk of hemodialysis patients for infections sustained by hepatitis viruses is likely to extend to a newly discovered parenterally transmitted virus, HGBV-C/HGV, able to cause acute and chronic hepatitis. The aim of this study was to assess the prevalence and clinical relevance of this infection in Italian hemodialysis patients. Nineteen of 100 patients (19%) on maintenance hemodialysis were viremic for HGBV-C/HGV, and all of them were infected with a HGV-like genotype. Eight of these patients were coinfected by hepatitis B or hepatitis C viruses. A clinical picture of chronic hepatitis was not appreciable in patients with isolated HGV infection and the presence of HGV did not appear to modify the clinical course of hepatitis B and hepatitis C infections.     

Cognitive—behavioral treatment of obsessive thoughts: A controlled study.

Twenty-nine patients with obsessive-compulsive disorder as diagnosed in accordance with the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised; American Psychiatric Association, 1987) who did not have overt compulsive rituals were randomly assigned to treatment and waiting-list conditions. Patients in the treatment condition received cognitive-behavioral therapy consisting of a detailed explanation of the occurrence and maintenance of obsessive thoughts, exposure to obsessive thoughts, response prevention of all neutralizing strategies, cognitive restructuring, and relapse prevention. Compared with waiting-list patients, treated patients improved significantly on measures of severity of obsessions, current functioning, self-report obsessive-compulsive symptoms, and anxiety. When waiting-list patients were subsequently treated, the combined group improved on all outcome measures. Treatment gains were maintained at 6-month follow-up. Results indicate that cognitive-behavioral therapy is effective in the treatment of patients with obsessive thoughts, a group that has often been considered resistant to treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Digital Footprinting: Uncovering Tourists with User-Generated Content

Novel methods and tools are being developed to explore the significance of the new types of user-related spatiotemporal data. This approach helps uncover the presence and movements of tourists from cell phone network data and the georeferenced photos they generate.