Labor Income Dynamics in Chile

This paper provides an empirical analysis of individual earnings using data from the personal income survey Encuesta Suplementaria de Ingresos. We find that the predictable component of income is humpshaped over the life-cycle, and that there are strong effects from education. The unpredictable component of income can be described by a very persistent permanent shock and a transitory shock. Our estimates are built from a panel of cohorts, so we use US data from the Panel Study of Income Dynamics (PSID) to provide a magnitude for the underestimation of variances. Surprisingly, we find that the variance of the permanent shock in Chile is around one fourth of the variance in the US, a result, perhaps, of the relative rigidity of the Chilean labor market.

A Validated Reversed-Phase HPLC Method for the Determination of Atorvastatin Calcium in Tablets

A Reversed-Phase Liquid Chromatographic (RP-LC) assay method was developed for the quantitative determination of atorvastatin calcium in the presence of its degradation products. The assay involved an isocratic elution of atorvastatin calcium in a LiChroCARTR 250*4 mm HPLC Cartridge LiChrospherR 100 RP-18 (5 μm) column using a mobile phase consisting of 0.1% acetic acid solution: acetonitrile (45:55, v/v), pH = 3.8. The flow rate was 0.8 mL/min and the analytes monitored at 246 nm. The assay method was found to be linear from 8.13 to 23.77 μg/mL. All the validation parameters were within the acceptance range. The developed method was successfully applied to estimate the amount of atorvastatin calcium in tablets.Fil: Simionato, Laura Daniela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Ferello, L.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Stamer. S.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Repetto, M. F.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Zubata, P. D.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Segall, Adriana Ines. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Increased flexibility in lab-on-chip design with a polymer patchwork approach

Nanofluidic structures are often the key element of many lab-on-chips for biomedical and environmental applications. The demand for these devices to be able to perform increasingly complex tasks triggers a request for increasing the performance of the fabrication methods. Soft lithography and poly(dimethylsiloxane) (PDMS) have since long been the basic ingredients for producing low-cost, biocompatible and flexible devices, replicating nanostructured masters. However, when the desired functionalities require the fabrication of shallow channels, the \u201croof collapse\u201d phenomenon, that can occur when sealing the replica, can impair the device functionalities. In this study, we demonstrate that a \u201cfocused drop-casting\u201d of h-PDMS (hard PDMS) on nanostructured regions, provides the necessary stiffness to avoid roof collapse, without increasing the probability of deep cracks formation, a drawback that shows up in the peel-off step, when h-PDMS is used all over the device area. With this new approach, we efficiently fabricate working devices with reproducible sub-100 nm structures. We verify the absence of roof collapse and deep cracks by optical microscopy and, in order to assess the advantages that are introduced by the proposed technique, the acquired images are compared with those of cracked devices, whose top layer, of h-PDMS, and with those of collapsed devices, made of standard PDMS. The geometry of the critical regions is studied by atomic force microscopy of their resin casts. The electrical resistance of the nanochannels is measured and shown to be compatible with the estimates that can be obtained from the geometry. The simplicity of the method and its reliability make it suitable for increasing the fabrication yield and reducing the costs of nanofluidic polymeric lab-on-chips

Energy in one dimensional linear waves in a string

We consider the energy density and energy transfer in small amplitude, one-dimensional waves on a string, and find that the common expressions used in textbooks for the introductory physics with calculus course give wrong results for some cases, including standing waves. We discuss the origin of the problem, and how it can be corrected in a way appropriate for the introductory calculus based physics course.Comment: 5 page

Uncertainty quantification in energy management procedures

Complex energy systems are made up of a number of components interacting together via different energy vectors. The assessment of their performance under dynamic working conditions, where user demand and energy prices vary over time, requires a simulation tool. Regardless of the accuracy of this procedure, the uncertainty in data, obtained both by measurements or by forecasting, is usually non-negligible and requires the study of the sensitivity of results versus input data. In this work, polynomial chaos expansion technique is used to evaluate the variation of cogeneration plant performance with respect to the uncertainty of energy prices and user requests. The procedure allows to obtain this information with a much lower computational cost than that of usual Monte-Carlo approaches. Furthermore, all the tools used in this paper, which were developed in Python, are published as free and open source software

A stereospecific one-pot synthesis of β-chloro esters via the BiCl<inf>3</inf> catalysed O-acylative cleavage of crowded epoxides

© 2015, Science Reviews 2000 Ltd. All rights reserved. A simple, one-pot procedure is described for the stereospecific preparation of β-chloro esters from the corresponding crowded epoxide

Wind tunnel tests of a hexadecagonal cylinder with imperfections and ancillaries: aerodynamic characterization and technical discussion

This paper evaluates and discusses the aerodynamic properties of a 16-sided polygonal cylinder with imper- fections and ancillaries investigated by wind tunnel tests. Two sectional models with different size have been realized, reproducing the peculiarities of real structures, such as the rounded corners, local protuberance due to weld bead, cables, ducts and the external ladder. The models have been subjected to static tests to measure the mean force coefficients and the Strouhal number varying angle of attack, flow velocity, turbulence intensity focusing on the effects of the imperfections and ancillaries on the aerodynamic loads with consideration of Reynolds number effects. The results provide an estimate of the aerodynamic coefficients for this type of ele- ments, quantify the influence of geometrical and flow properties on the aerodynamic behaviour and point out the sensitivity of such polygonal cross-section to galloping instability

Detection of the magneto-structural phase coexistence in MnAs epilayers at a very early stage

We report on the appearance of magnetic stripes in MnAs/GaAs(100) epilayers at temperatures well below the ferromagnetic transition of the system. The study has been performed by ferromagnetic resonance experiments (FMR) on MnAs epilayers grown on (100) and (111) GaAs substrates. The FMR spectra of the MnAs/GaAs(100) samples at 180 K reveal the appearance of zones of different magnetic behavior with respect to the low-temperature homogeneous ferromagnetic phase. The angular and the temperature dependence of the spectra serve us to detect the inter-growth of the non-magnetic phase into the ferromagnetic phase at a very early stage of the process. The experimental data show that the new phase nucleates in a self-arranged array of stripes in MnAs/GaAs(100) thin films while it grows randomly in the same films grown on GaAs(111).Comment: 8 pages, 5 figure