Efficient heuristics for the design of ring networks

In telecommunications, the Ring Design Problem (RDP) lies at the heart ofmetropolitan area network design. We propose an integer programming formulation for the RDP, as well as several ring construction and post-optimization heuristics. These heuristics are tested and compared on a series of test problems.     

Species identification of meat products by ELISA

ELISA methods used in this study are proved to detect low contents of animal species (pork, beef, sheep and poultry), even in highly processed foods. They present the advantages of being robust, cheap and easy to perform. Nevertheless, F factors, determining the threshold values of the test, need to be validated for each species.     

Formation of the Perovskite Phase in the PbMg1/3Nb2/3O3─PbTiO3 System

The reaction sequences during calcination of oxide mixtures were studied for the PbMg_1/3Nb_2/3O₃─PbTiO₃ (PMN-PT) system. The effect of reactivity and composition of the starting mixtures was investigated. In the present study, a B-site-deficient, cubic pyrochlore phase in the PbO-Nb₂O₅ system was formed at 500°C. The perovskite phase of PMN was formed at 7007deg;C through the diffusion of MgO into the pyrochlore phase. The lattice parameter of the pyrochlore phase decreased as this transformation to perovskite progressed.     

Enhancement of eicosaenoic acid lipoxygenation in human platelets by 12-hydroperoxy derivative of arachidonic acid

Human platelet lipoxygenase activity toward several eicosaenoic acids was measured in intact cells as well as in subcellular fractions (cytosol and membranes). In whole platelets, the lipoxygenation of eicosaenoic acids was enhanced greatly by high concentrations of aspirin, which partially inhibit the peroxidase activity associated with the pathway. The lipoxygenation also was increased by arachidonic acid (AA) or its lipoxygenase product, 12-hydroxyperoxy-eicosatetraenoic acid (12-HPETE). Similarly, prostanoid precursors, dihomogammalinolenic (DHLA) and eicosapentaenoic (EPA) acids also were better converted by cyclooxygenase in the presence of AA or 12-HPETE. Among the eicosaenoic acids tested, EPA oxygenation was affected most. Using cytosol or membranes as the lipoxygenase source instead of whole cells led to completely different results. AA exerted a competitive inhibition upon the other eicosaenoic acid oxygenation except that of EPA, for which a dual effect of AA was observed. This makes questionable the use of platelet subfractions for investigating lipoxygenase activity. We conclude that platelet lipoxygenation of eicosaenoic acids appears peroxide-dependent, especially for apparent poor substrates like EPA. This might be relevant in respect to 12-HPETE, which is the main hydroperoxy derivative to be produced during platelet activation.     

Predictive factors of chronic post-traumatic stress disorder 6 months after a road traffic accident

Background

This study sets out to identify risk factors for post-traumatic stress disorder (PTSD) after a road traffic accident with a view to improving prevention.

Methods

The study used a prospective cohort of road traffic accident casualties. All subjects over 15 years of age were recruited in the course of an interview conducted while they were receiving care in a hospital of the Rhône area administrative département. Six months after their accident, they answered a self-administered postal questionnaire that included the Post-traumatic Check-List Scale (PCLS) in order to evaluate PTSD. Multivariate logistic regression analysis was conducted to compare those subjects with a PCLS score of 44 or over with those with a lower score, in order to identify factors that might be associated with PTSD.

Results

592 subjects (out of 1168) returned the 6-month questionnaire and 541 completed the PCLS test. One hundred subjects had a PCLS score ≥44, suggesting PTSD, and 441 subjects did not. The factors associated with PTSD were initial injury severity, post-traumatic amnesia, the feeling of not being responsible for their accident and persistent pain 6 months after it. A lower odds-ratio was associated with users of two-wheel than four-wheel motor vehicles (OR = 0.4; 0.2–0.9).

Conclusion

Besides predictive factors for PTSD (injury severity, post-traumatic amnesia and the feeling of not being responsible for their accident), our study suggested a reduced risk of PTSD among two-wheel motor vehicle users.     

A new continuous-flow recycle microwave reactor for homogeneous and heterogeneous chemical reactions

A new continuous-flow recycle microwave reactor suitable for organic synthesis has been developed to handle 0.51 quantities of reagents. The apparatus, which is designed for laboratory use, operates at atmospheric pressure in open- or closed-loop mode. It is fitted with a temperature control system. We describe this novel reactor and illustrate its efficiency with examples of organic syntheses carried out using both homogeneous and heterogeneous reactions.     

Clients Who Stalk Psychologists: Prevalence, Methods, and Motives.

There is emerging recognition that psychologists are susceptible to various forms of intrusiveness by clients, including stalking. Information regarding the contexts in which stalking emerges and the behaviors to which clinicians are subjected is limited. A random sample of Australian psychologists (N = 1,750) was surveyed to ascertain the prevalence, nature, and occupational impact of stalking by clients. Of the 830 respondents, 19.5% had been stalked for 2 weeks or more. Psychologists typically perceived the stalking to be motivated by resentment (42%) or infatuation (19%). Most practitioners altered their professional practice as a consequence of the harassment and 29% considered leaving the profession. Stalking by clients is a salient professional issue that requires greater attention to better manage conduct that is potentially damaging to both therapists and clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduced visual capacity increases the risk of accidents in street traffic]

Six patients diagnosed with obstructive sleep apnea completed titration of an adjustable oral appliance, called the Silencer, during a single night of polysomnography. This protocol allowed for rapid titration of the oral appliance and effective treatment of sleep apnea. Variables which showed improvement included frequency of obstructive events, oxyhemoglobin saturation and snoring. Dental appliance adjustments with the silencer device can be made within three minutes. We have demonstrated that incremental mandibular advancement and repositioning allow us to determine the most effective jaw position to treat sleep apnea and snoring, which is also most likely to be tolerated by the patient.     

Hemispheric Specialization in the Primary Auditory Area of Awake and Anesthetized Starlings (Sturnus vulgaris).

Although evidence exists for a lateralization of song production, few studies have focused on the perceptual aspect of lateralization in songbirds. In the present study, the authors recorded neuronal responses to a variety of species-specific and artificial, nonspecific stimuli in both hemispheres of awake and anesthetized male starlings (Sturnus vulgaris). Recordings were made in the primary auditory area of the songbird brain, the Field L complex. The right hemisphere exhibited significantly more responsive units than the left hemisphere in awake birds, and this difference was significantly reduced in anesthetized birds. Furthermore, clear hemispheric specialization toward categories of behaviorally relevant stimuli and precise parameters of these stimuli were found. The main auditory area of the starling's brain thus appears to show some degree of lateralization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)