415 research outputs found

    Arc-Smooth Continua

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    Continua admitting arc-structures and arc-smooth continua are introduced as higher dimensional analogues of dendroids and smooth dendroids, respectively. These continua include such spaces as: cones over compacta, convex continua in l2, strongly convex metric continua, injectively metrizable continua, as well as various topological semigroups, partially ordered spaces, and hyperspaces. The arc-smooth continua are shown to coincide with the freely contractible continua and with the metric K-spaces of Stadtlander. Known characterizations of smoothness in dendroids involving closed partial orders, the set function T, radially convex metrics, continuous selections, and order preserving mappings are extended to the setting of continua with arc-structures. Various consequences of the special contractibility properties of arc-smooth continua are also obtained

    IONTOPHORETIC DRUG DELIVERY: A NOVEL APPROACH THROUGH TRANSDERMAL ROUTE

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    ABSTRACT The goal of delivery system is to get optimal therapeutic management. But, it still remains a challenge in the field of pharmaceuticals for delivery of ionic species and some non ionic. Several transdermal approaches have been used and recently the Iontophoretic technique has been widely used. This technique of facilitated movement of ion across a membrane under the influence of an externally applied potential difference is one of the most promising physical penetrations enhancing method. The rationale behind using this technique is the capability of this method to increase the systemic delivery of high molecular weight compounds with controlled input kinetics. Also improved systemic bioavailability, ensuring from bypassing the first pass metabolism. This article presents a review of literature relating to iontophoresis. This review briefly describes the history of iontophoresis and discussion of factors which affect Iontophoretic drug delivery. Present review also provides its applications for various clinical conditions

    Impact of age norms and stereotypes on managers' hiring decisions of retirees

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    Purpose -Our study investigates the role of managers in the re-employment of early retirees and asks what the effect is of managers’ age norms and stereotypes on managers’ employment decisions. Design/methodology/approach- A combination of a factorial study and a survey was conducted. First, information on the age norms and stereotypes was collected. Secondly, profiles of hypothetical retired job applicants were presented to the employers, who were asked to make a specific hiring decision. The information collected during both studies was combined in the analysis and multilevel models were estimated. Findings -The results indicate that higher age norms result in a higher propensity to hire an early retiree. Stereotypes, by contrast, do not influence managers’ decisions. Early retirees’ chances for re-employment are also related to their own circumstances (physical appearance and relevant experience) and organisational forces, as they are hired when organisations face labour force shortages. Research limitation / implications – with the use of vignettes study we deal with hypothetical hiring situation. Originality value- Although the effect of age norms and age stereotypes has been often suggested, not much empirical evidence was presented to support this notion. Our study estimates the effect of age norms and stereotypes on hiring decision. key words: bridge employment; early retirees; age norms; age stereotypes; multilevel models.

    Starfire Optical Range 3.5-m telescope adaptive optical system

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    A 941 channel, 1500 Hertz frame rate adaptive optical (AO) system has been installed and tested in the coude path of the 3.5m telescope at the USAF Research Laboratory Starfire Optical Range. This paper describes the design and measured performance of the principal components comprising this system and present sample results from the first closed-loop test of the system on stars and an artificial source simulator

    Modern optical astronomy: technology and impact of interferometry

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    The present `state of the art' and the path to future progress in high spatial resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the origin, properties, optical effects of turbulence in the Earth's atmosphere, the passive methods that are applied on a single telescope to overcome atmospheric image degradation such as speckle interferometry, and various other techniques. These topics include differential speckle interferometry, speckle spectroscopy and polarimetry, phase diversity, wavefront shearing interferometry, phase-closure methods, dark speckle imaging, as well as the limitations imposed by the detectors on the performance of speckle imaging. A brief account is given of the technological innovation of adaptive-optics (AO) to compensate such atmospheric effects on the image in real time. A major advancement involves the transition from single-aperture to the dilute-aperture interferometry using multiple telescopes. Therefore, the review deals with recent developments involving ground-based, and space-based optical arrays. Emphasis is placed on the problems specific to delay-lines, beam recombination, polarization, dispersion, fringe-tracking, bootstrapping, coherencing and cophasing, and recovery of the visibility functions. The role of AO in enhancing visibilities is also discussed. The applications of interferometry, such as imaging, astrometry, and nulling are described. The mathematical intricacies of the various `post-detection' image-processing techniques are examined critically. The review concludes with a discussion of the astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics, 2002, to appear in April issu
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