The origin of color gradients in elliptical galaxies is examined by comparing model gradients with those observed in the Hubble Deep Field. The models are constructed so as to reproduce color gradients in local elliptical galaxies either by a metallicity gradient or by an age gradient. By looking back a sequence of color gradient as a function of redshift, the age metallicity degeneracy is solv...

PURPOSE To describe the rationale behind elliptical and other transition designs used with the excimer laser. SETTING Casey Eye Institute, Oregon Health Sciences University, Portland, Oregon, USA. METHODS Ablation zone designs were analyzed for the number of transition points for myopia and hyperopia. The advantages and disadvantages of elliptical transition zones are demonstrated graphical...

Introduction: The elliptical trainer, developed to simulate running while minimizing joint loads, elicits a unique lower extremity biomechanical response. The purpose of this study was to examine the angular kinematics, peak net joint moments, and peak joint powers at the hip, knee and ankle joints while exercising at three different ramp settings on the elliptical trainer exercise machine (Pre...

In this paper, a class of extended lower and upper levelings is investigated. Here, some conditions are imposed to the criteria for building extended lower and upper levelings in order to generate openings and closings with reconstruction criteria. The idea of building these new openings and closings comes from the notions of morphological filters by reconstruction and levelings. The main goal ...

This paper analyzes the impact of international trade on the quality of institutions, such as contract enforcement, property rights, or investor protection. It presents a model in which institutional differences play two roles: they create rents for some parties within the economy, and they are a source of comparative advantage in trade. Institutional quality is determined as an equilibrium of ...

Recent work shows that transcription factors are necessary for stomatal movements in plants. Different members of the plant-specific R2R3-MYB transcription factor family are required for mediating stomatal opening in response to light and stomatal closure in response to darkness.

In this paper, a class of transformations with reconstruction criteria is investigated. This class of transformations was initially proposed for obtaining intermediate results between the morphological opening and the opening by reconstruction. Here, the transformations are presented in the general case, as in the reconstruction transformations case, by imposing some conditions on the marker. T...

A large number of X-ray sources in globular clusters of galaxies other than the Milky Way has been found with Chandra. We discuss three issues relating to these sources. The X-ray luminosity function (XLF) of the sources in globular clusters of M31 is marginally compatible with the XLF of globular clusters of the Milky Way. The individual XLFs of a dozen elliptical galaxies, after correction fo...

The aim of this paper is to derive local influence curvatures under various perturbation schemes for elliptical linear models with longitudinal structure. The elliptical class provides a useful generalization of the normal model since it covers both lightand heavy-tailed distributions for the errors, such as Student-t, power exponential, contaminated normal, among others. It is well known that ...

As a kind of important flexible joint, two-axis flexure hinges can realize in-plane and out-of-plane motions and can be used for constructing flexure-based spatial compliant mechanisms. The paper introduces a common two-axis elliptical-arc-filleted flexure hinge that is generated by two different elliptical-arc-filleted cutout profiles and that provides some new hinge types. The analytical comp...