Correlation properties of binary sequences generated by the logistic map-application to DS-CDMA

In this paper, we will show that a simple one dimension non-linear map allows generating symbolic sequences that have better statistical properties then classical pseudo random ones. Using performance criterion that is suitable for CDMA application, the performances of symbolic sequences will be compared to the performances of Gold ones. This comparison will show that non-linear systems generate sequences that allow a signal to noise ratio better then pseudo-random sequence generated by linear shift registers

Exploring Unstsable Periodic Orbits Using Super Stable Ones

This paper deals with Super Stable Orbits (SSOs) of the logistic map, and how they can be used to describe Unstable Periodic Orbits (UPOs).~We will show that Unstable Periodic Orbits have almost the same correlation properties as Super Stable ones from which they were born, and this will be confirmed by simulations. We will present one application, a method to detect UPOs merged in a strange attractor

AC Electrical Arcs With Graphite Electrodes

International audienceIn order to improve the safety of potentially hazardous situations such as "hot" disconnections of equipment or deteriorated connections, a deeper knowledge of the characteristics of the arcs thus produced and their subsequent damage to contact materials, insulating and wiring, is needed. Numerous studies have been performed on DC arcs as they appear in automotive applications. There is however, a strong need to study arcs in the domain of alternating current, in order to understand their consequences to safety and reliability in domestic applications. The purpose of this study is to extend our knowledge of AC-arc characteristics and consequences (e.g. risk of fire ignition) in order to improve the reliability of security devices such as arc fault circuit interrupters (AFCI). Conditions when arcs could initiate and reinitiate are determined, for a voltage of 220V (50Hz), a current from 1A to 4A, electrodes made with copper or graphite and gaps from 10μm to 1000μm. The conclusion of this work is that arcs produced by graphite electrodes present some characteristics which differ significantly from metallic electrode arcs, especially regarding ignition and re-ignition capability. This behavior should be taken into count for safety considerations

[Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998)].

&lt;p&gt;Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998). The choice of antimicrobial therapy for the treatment of bacteremia is often empirical and based on the knowledge of susceptibility profiles of the most common bacteria causing such infections. This study determines the bacterial etiology of bacteremic episodes and antimicrobial susceptibility patterns recorded at a teaching hospital, from January 1993 to December 1998. We collected 2979 strains responsible for bacteremia. Gram negative bacteria were predominant (60%). The organisms recovered most frequently were Staphylococcus aureus (18.9%), Escherichia coli (14.7%), Klebsiella pneumoniae (14%) and Pseudomonas aeruginosa (7.6%). The incidence of resistance to methicillin were 17.4% for Staphylococcus aureus and 26.8% for coagulase negative Staphylococcus. No resistance to glycopeptides was observed among the enterococci and staphylococci studied. 27.7% of enterobacteriaceae were resistant to third generation cephalosporins. Imipenem was the most active agent against gram negative bacteria. To carry out a surveillance of bacteremic episodes occurring at every hospital, it is necessary to provide valuable information which should be the basis for effective empiric therapy.&lt;/p&gt;</p

Characteristics of arcs between carbon electrodes

International audienc

Exploring the stability of HEXACO-60 structure and the association of gender, age, and social position with personality traits across 18 countries.

The present paper tests the cross-national stability of the HEXACO-60 structure across 18 countries from four continents. Gender and age differences across countries will be examined. Finally, this is the first study to explicitly analyze the relationships between the HEXACO and social position. Ten thousand two hundred and ninety eight subjects (5,410 women and 4,888 men) from 18 countries and 13 languages were analyzed. Confirmatory factor analysis techniques were used to test configural, metric and scalar invariance models. Congruence coefficients with the original structure of the HEXACO-60 were computed for every culture. Effect sizes of gender, age, and social position factors across countries were also computed. HEXACO-60 demonstrates configural and metric invariance, but not scalar invariance. Congruence coefficients show a great equivalence in almost all countries and factors. Only Emotionality presents a large gender difference across countries. No relevant effect of age is observed. A profile of high scores on Honesty-Humility, Extraversion, Conscientiousness, and Openness to Experience, and low scores on Emotionality increases the likelihood of achieving a higher social position, although the effect sizes are small. HEXACO-60 is a useful instrument to conduct personality trait research and practice around the world. Implications of gender, social position, and country differences are discussed

Factors associated with 56-day non-return rate in dairy cattle

The objective of this work was to identify factors associated with the 56-day non-return rate (56-NRR) in dairy herds in the Galician region, Spain, and to estimate it for individual Holstein bulls. The experiment was carried out in herds originated from North-West Spain, from September 2008 to August 2009. Data of the 76,440 first inseminations performed during this period were gathered. Candidate factors were tested for their association with the 56-NRR by using a logistic model (binomial). Afterwards, 37 sires with a minimum of 150 first performed inseminations were individually evaluated. Logistic models were also estimated for each bull, and predicted individual 56-NRR rate values were calculated as a solution for the model parameters. Logistic regression found four major factors associated with 56-NRR in lactating cows: age at insemination, days from calving to insemination, milk production level at the time of insemination, and herd size. First-service conception rate, when a particular sire was used, was higher for heifers (0.71) than for lactating cows (0.52). Non-return rates were highly variable among bulls. Asignificant part of the herd-level variation of 56-NRR of Holstein cattle seems attributable to the service sire. High correlation level between observed and predicted 56-NRR was found