Robustness bounds for LQ regulators

A robustification procedure for LQ state feedback design is presented. Such a procedure consists of choosing the state and input weighting matrices according to the kind of uncertainties on the system. Both structured and norm-bounded additive uncertainties are addressed, and upper bounds for the uncertainties that do not destabilize the closed-loop system are presented. Connections with the quadratic stabilizability problem are established     

Validation de la traduction de l'Inventaire d'épuisement professionnel de Maslach et Jackson.

Studied the psychometric properties of a French translation of the MBI. Ss were 260 day-care workers (mean age 29 yrs) in Study 1 and 123 nurses (mean age 38 yrs) in Study 2. Study 1 evaluated the internal consistency, factorial validity, temporal stability, and predictive validity of the MBI. Study 2 analyzed the convergent validity of the MBI in relation to measures of depression, anxiety, psychological stress, and other psychological symptoms. The distribution of low, average, and high professional-burnout scores in these 2 samples was compared to American norms. Several French-language instruments were used, including French versions of the MBI (C. Maslach and S. Jackson, 1981), the Beck Depression Inventory, the State–Trait Anxiety Inventory, and the Brief Symptom Inventory (L. R. Derogatis, 1983). (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Belief in a just world and physical attractiveness stereotyping.

Just-world theory provides a possible explanation of physical attractiveness stereotyping, in that believing in a just world should lead to a positive bias toward "winners," such as the physically attractive. Several hypotheses derived from this premise were tested by having adults complete the Just World Scale and rate the personality traits and expected life outcomes of an attractive or unattractive stimulus person. Predictions for the personality trait ratings were borne out for male but not for female stimulus persons: (a) Believers in a just world perceived the personalities of attractive, male stimulus persons as more socially desirable than nonbelievers and also attributed more socially desirable personalities to male stimulus persons who were attractive rather than unattractive; and (b) no effects were found for female stimulus persons. Predictions for the life-outcome ratings and differences in correlations between personality and life-outcome ratings as a function of belief in a just world were clearly supported. Implications for just-world theory, status-characteristics theory, and physical attractiveness stereotyping are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using and misusing factor analysis to explore group cohesion

Group cohesion is an important construct in understanding the behavior of different types of groups. However, controversy exists about how to conceptualize and measure cohesion, and a central issue is its dimensionality. Consequently, researchers have used factor analysis to examine the structure of the construct of cohesion and measures of it. Our goals in writing this article were to review critically how factor analysis has been used to understand group cohesion, make some recommendations for future factor analytic work, and point out some weaknesses and strengths in using factor analysis to explore cohesion.     

Nouvelles familles de phases MIMII2Nb3O10 a feuillets “perovskites”

A new series of phases M^ICa₂Nb₃O₁₀ (M^I = Li, Na, K, Rb, Cs, NH₄, Tl) has been prepared and characterized. Their unit cells are tetragonal. The structures consist of treble perovskite sheets interleaved with M^I sheets. According to the M^I nature, the relative displacement of adjacent treble perovskite sheets, parallel to (001) is O, $\text{b}\text{4}$ or $\text{(}\text{a}\text{+}\text{b}\text{)}\text{4}$     

Measuring ocular aberrations in the peripheral visual field using Hartmann-Shack aberrometry

We have used the Hartmann-Shack technique previously to measure ocular aberrations along the horizontal meridian of the visual field. This requires considerable modifications from the technique for measuring the aberrations corresponding to the fovea. We now further develop the technique so that it can be used for any meridian of the visual field. Allowance is made for any auxiliary optics placed in front of the eye to compensate for the limited range of the Hartmann-Shack technique and for the case where aberrations are estimated at a wavelength other than the measuring wavelength. Zernike wave aberrations are converted to peripheral refractions. Examples are presented showing the developments, and we discuss change in wave aberrations when converting from a circular to an elliptical pupil.     

Structural Characterization of Highly Conducting AlGaN (<Emphasis Type="Italic">x</Emphasis> > 50%) for Deep-Ultraviolet Light-Emitting Diode

Off-axis reciprocal-space mapping was performed on aluminum gallium nitride deep-ultraviolet light-emitting diode base layers. The results indicate that aluminum gallium nitride films growing on aluminum nitride-on-sapphire templates initially grow in compression, nearly lattice matched to the relaxed aluminum nitride buffer layer with approximately 0.5% biaxial strain. This compressive strain may be partially relieved over the course of the thick aluminum gallium nitride growth when a high-quality aluminum nitride and superlattice layer is used. Additionally, a growth interruption appears to allow growth of an unstrained aluminum gallium nitride layer without a gradual release of compressive strain. Growth on a bulk aluminum nitride substrate appears to yield an aluminum gallium nitride layer in tension rather than compression.     

Exploring Photoswitchable Binding Interactions with Small-Molecule- and Peptide-Based Inhibitors of Trypsin

The ability to photochemically activate a drug, both when and where needed, requires optimisation of the difference in biological activity between each isomeric state. As a step to this goal, we report small-molecule- and peptide-based inhibitors of the same protease—trypsin—to better understand how photoswitchable drugs interact with their biological target. The best peptidic inhibitor displayed a more than fivefold difference in inhibitory activity between isomeric states, whereas the best small-molecule inhibitor only showed a 3.4-fold difference. Docking and molecular modelling suggest this result is due to a large change in 3D structure in the key binding residues of the peptidic inhibitor upon isomerisation; this is not observed for the small-molecule inhibitor. Hence, we demonstrate that significant structural changes in critical binding motifs upon irradiation are essential for maximising the difference in biological activity between isomeric states. This is an important consideration in the design of future photoswitchable drugs for clinical applications.