The level set method for the two-sided max-plus eigenproblem

We consider the max-plus analogue of the eigenproblem for matrix pencils, A???x?=?λ???B???x. We show that the spectrum of (A,B) (i.e., the set of possible values of λ), which is a finite union of intervals, can be computed in pseudo-polynomial number of operations, by a (pseudo-polynomial) number of calls to an oracle that computes the value of a mean payoff game. The proof relies on the introduction of a spectral function, which we interpret in terms of the least Chebyshev distance between A???x and λ???B???x. The spectrum is obtained as the zero level set of this function.     

Quantification of two decades of shallow-water coral reef habitat decline in the Florida Keys National Marine Sanctuary using Landsat data (1984–2002)

The loss of coral reef habitats has been witnessed at a global scale including in the Florida Keys and the Caribbean. In addition to field surveys that can be spatially limited, remote sensing can provide a synoptic view of the changes occurring on coral reef habitats. Here, we utilize an 18-year time series of Landsat 5/TM and 7/ETM+ images to assess changes in eight coral reef sites in the Florida Keys National Marine Sanctuary, namely Carysfort Reef, Grecian Rocks, Molasses Reef, Conch Reef, Sombrero Reef, Looe Key Reef, Western Sambo and Sand Key Reef. Twenty-eight Landsat images (1984–2002) were used, with imagery gathered every 2 years during spring, and every 6 years during fall. The image dataset was georectified, calibrated to remote sensing reflectance and corrected for atmospheric and water-column effects. A Mahalanobis distance classification was trained for four habitat classes (‘coral’, ‘sand’, ‘bare hardbottom’ and ‘covered hardbottom’) using in situ ground-truthing data collected in 2003–2004 and using the spectral statistics from a 2002 image. The red band was considered useful only for benthic habitats in depths less than 6 m. Overall mean coral habitat loss for all sites classified by Landsat was 61% (3.4%/year), from a percentage habitat cover of 19% (1984) down to 7.6% (2002). The classification results for the eight different sites were critically reviewed. A detailed pixel by pixel examination of the spatial patterns across time suggests that the results range from ecologically plausible to unreliable due to spatial inconsistencies and/or improbable ecological successions. In situ monitoring data acquired by the Coral Reef Evaluation and Monitoring Project (CREMP) for the eight reef sites between 1996 and 2002 showed a loss in coral cover of 52% (8.7%/year), whereas the Landsat-derived coral habitat areas decreased by 37% (6.2%/year). A direct trend comparison between the entire CREMP percent coral cover data set (1996–2004) and the entire Landsat-derived coral habitat areas showed no significant difference between the two time series (ANCOVA; F-test, p = 0.303, n = 32), despite the different scales of measurements.     

La représentation des causes de l'infériorité économique des québécois francophones.

Studied the causal interpretations of wage disparities among linguistic groups in Québec, assessed the effects of these interpretations on intergroup relations, and examined social and cultural dimensions of causal attributions. Human subjects: 36 male and female French-Canadian adults (university students). 36 male and female English-Canadian adults (university students). Ss' mean age was 21.7 yrs. Ss were given a questionnaire soliciting information on demographic factors and opinions on the importance of various factors in explaining the wage disparity between French-speaking and English-speaking Canadians. Two questionnaire forms were used, 1 containing an information sheet on the economic disadvantages of French-speaking Canadians, and 1 without the information sheet. Interpretations of the causes of the economic gap between French-speaking and English-speaking Canadians were evaluated using an analysis of variance (ANOVA) according to language and whether or not the Ss had received the information sheet. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modélisation de l’impédance de transfert des câbles coaxiaux à blindages multiples

The shielding effectiveness of multishielded coaxial cables is determinated through the concept of the equivalent transfer impedance. The transfer impedance is computed from the main parameters of the coaxial structure. We describe in this paper the theoretical formulation to evaluate the amplitude of the disturbing voltage at the end of the cable flowed by the disturbing current. This result is used for the computation of the equivalent transfer impedance when the cable is made of various shields for exemple: homogeneous screens or braids. A comparison with the experimental results is also described.     

Size effects on the DC characteristics and low frequency noise of double polysilicon NPN bipolar transistors

DC and low frequency noise measurements have been carried out for double polysilicon NPN bipolar transistors. Our experiments have highlighted unexpected geometrical dependencies for the base saturation current density and low frequency noise. A model, taking into account a variation of the interfacial oxide thickness at the periphery of the emitter has been proposed and it has been successfully applied to the experimental results.     

Response of the Rhône deltaic margin to loading and subsidence during the last climatic cycle

Passive continental margin subsidence is initiated by the synrift mechanical stretching of the lithospheric upper brittle layer and continues during the postrift phase; the thermal cooling and contraction of the upwelled asthenosphere forces the margin to subside in addition to the overloads from sea water and sediments. Therefore, the total subsidence in stretched basins includes fault-controlled initial sinking, thermal subsidence and flexural isostatic compensations. Decoupling and estimating the different components of this subsidence from stratigraphic analysis and restricted geophysical and sedimentological databases remains problematic. In particular, backstripping the sediment layers requires a well-constrained geological framework. A method is proposed here to investigate the subsidence history of a margin based on forward stratigraphic modelling. Using the Sedflux model, several experiments are done using generally agreed upon assumptions on the parameters describing lithospheric rheology and isostatic behaviour of a margin. The stratigraphic modelling of the Rhône deltaic margin during the last climatic cycle (125 kyr) provides an assessment of these parameter estimates and their influence on geohistory (tectonic/thermal subsidence and sediment loading). The model results confirm the important impact of water loading on vertical deflection along the platform between glacial low sea-level and interglacial high sea-level. Based on Gulf of Lions (NW Mediterranean) observations, a conceptual method that uses the stratigraphic simulations is produced in order to evaluate the different components of the total subsidence of a margin, and, in particular, the relative impact of tectonic subsidence and sediment load.     

Dogmatisme paternel, niveau socio-économique et performance cognitive de pré-adolescent(e)s.

Studied the association among paternal dogmatism, socioeconomic status (SES), and cognitive development using Piagetian tasks. Human subjects: 98 male and female French-Canadian schoolage children and adolescents (aged 144–171 mo) (1st class of students in the secondary school). 98 male French-Canadian adults (aged 32–62 yrs). All Ss were from 2-parent families and consisted of 50 father–daughter and 48 father–son dyads. Paternal dogmatism was measured using the French-Canadian version of the Rokeach Scale by M. Rokeach (1960). Cognitive levels were evaluated using Piaget and Inhelder"s Permutations Test (1951). Ss" SES was measured using B. R. Blishen and H. A. McRobert"s Socioeconomic Index (1976). The results of the cognitive performance tests were analyzed statistically according to age, sex, dogmatism, and SES, using an analysis of variance (ANOVA). (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)