PC-based hierarchical manufacturing cell control

Robots in the industrial factory plant build the backbone for CIM, which is outlined to be the factory automation strategy of the future. In this paper a hierarchical manufacturing cell control system for robotic work cells is described. This approach is based on low-cost personal computer hardware and consists of two different control systems, one for the robot control tasks and another for the work cell control tasks. The underlying concept is based on a strategic architectural model for hierarchical manufacturing control, where it focuses on the process sequence coordination and the process control in the bottom hierarchical layers.     

Stereological image analysis of cultured human melanocytes observed by transmission electron microscopy

The aims of the study were to write an image analysis (IA) program allowing the stereological quantification of human epidermal melanocyte melanization at the ultrastructural level and to specify the suitable preparative methods, in keeping with IA limits and stereological principles. Micrographs of cultured human melanocytes obtained in transmission electron microscopy were digitized with a scanner. The key step of the designed IA program is a thresholding based on the gray levels. Hence, gray level histograms (pixel frequency as a function of gray level) of melanocyte images exhibit a peak specific to melanin. The gray level thresholding used consists in isolating the melanin pixels that form profiles on a binary image and in storing the numerical data produced for a given melanocyte profile. These primary data are used to calculate numerous parameters via stereology with melanocyte cytoplasm and melanized melanosome as main reference spaces. The most important stereological parameters obtained are v(mi,cy) (melanin volume per average cell), v(mi,m) (melanin volume per average melanized melanosome), and nm (number of melanized melanosomes per average cell), and their validity is discussed. Melanocytes embedded in situ were abandoned for stereological reasons but pelleted melanocytes were found suitable. Using this computerized tool and stereology, we are able to perform quantitative studies producing varied data even from small cell samples. To our knowledge, this is the first stereological approach for quantifying intracellular melanization. A quantitative comparison of spectrophotometrical results (melanin assay) with stereological results obtained in ultraviolet B-irradiated Caucasian epidermal melanocytes will be performed in order to appraise this method.     

Microtubule structure studied by quick freezing: Cryo-electron microscopy and freeze fracture

Microtubules have been quickly frozen and examined by electron microscopy using several techniques: (1) freezing of a thin layer of solution by plunging into cryogen, followed by cryo-electron microscopy of the unstained vitrified samples; (2) freezing by the propane-jet method, followed by freeze fracturing and metal replication. The unstained frozen-hydrated microtubules show a structure in agreement with X-ray diffraction data; they differ from negatively stained particles mainly by the better preservation of cylindrical shape. Secondly, they reveal a supertwist of the profilaments that is not detected reliably by other methods. This allows a determination of the number of protofilaments and the polarity. The structural resolution of unstained microtubules is similar to that of stained ones (about 2–3 nm); it is limited by low contrast and lack of crystalline order. Propane-jet or cryo-block freezing followed by freeze fracturing reveals the structures of the inner and outer surfaces of the microtubule wall at a resolution of 4 nm or better. The outside is dominated by the longitudinal protofilaments whereas on the inside one observes tilted cross-striations. Although the freezing temperatures of the two methods are different (liquid nitrogen or helium) they yield similar results for the case of thin layers of protein solution.     

Observability of decoupled time-varying multivariable systems

The decoupling of a time-varying multivariable system by state-variable feedback does not guarantee the observability of the decoupled system. In the letter, a necessary and sufficient condition is derived for the observability of these systems in the time-variable case.     

Pupil response of hetero- and homosexual males to pictures of men and women: A pilot study.

The pupil response of each individual in a group of heterosexual males was greater when looking at pictures of women than when looking at pictures of men. Homosexual male Ss responded in the opposite direction. Measurement of changes in pupil size permitted clear-cut discrimination between the 2 groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mecanismes de colmatage et performances comparées de quatre membranes d'alumine: Cas de l'ultrafiltration de gelatine

This paper deals with gelatin ultrafiltration using alumina membranes of various pore sizes (0.2, 0.8, 1.4 et 2.0 μm). Pressure, tangential velocity and concentration effects are successively examined. From both a quantitative analysis of experimental data (pure solvent fluxes with clean or prefouled membranes, ultrafiltration fluxes, percent protein rejection) and the application of traditional model equations (filtration theory, film model), fundamental hypotheses are suggested concerning membrane functional characteristics. In particular, it is how fouling mechanisms and protein deposit structures are related to membrane characteristics. Finally, a comparison of membrane performances leads to the conclusion that the best fluxes and percent protein rejections are obtained using the 0.2 μm pore size membrane.     

Three-dimensional theory of free electron lasers with an axial guide field

The collective interaction in a free electron laser with a combined helical wiggler and uniform axial guide field is presented in the low-gain regime. The wiggler model we employ is fully self-consistent and includes all transverse inhomogeneities. The analysis is performed for a free electron laser (FEL) amplifier in which the radial dependence of the radiation is treated using both the TE and TM waveguide modes. Substantial discrepancies are found to exist between the results for the realizable and ideal wigglers, and a selection rule relating the TElnand TMlnmodes with resonant amplification at thelth harmonic of the FEL Doppler upshift.     

Social functioning among girls with fragile X or Turner syndrome and their sisters

Social behaviors among two genetically homogeneous groups--girls with fragile X (fraX) or Turner syndrome (TS)--were examined to address the role of family environment versus biological determinants of social dysfunction in girls with these disorders. Using a sibling pair design, girls with fraX or TS were compared with their own sisters on measures of IQ and social functioning. The 8 girls with fraX and the 9 girls with TS had lower FSIQ scores and higher ratings of social and attention problems relative to their own sisters. Girls with fraX also had higher ratings of withdrawn behaviors, relative to their own sisters. The unaffected sisters were not rated as demonstrating any difficulties in these areas, relative to controls. Correlations between problem ratings and FSIQ were not statistically significant. Although these preliminary findings do not indicate a lack of familial impact on social development in girls with either disorder, the results provide preliminary evidence that social dysfunction reported for girls with fraX or TS cannot be attributed solely, nor primarily, to global aspects of the family environment.