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San Bernardo, Chile

The University of Santiago, Chile is one of the oldest public universities in Chile. The institution was born as Escuela de Artes y Oficios in 1849, under the government of Manuel Bulnes. It became Universidad Técnica del Estado in 1947, with various campuses throughout the country. In 1981, as a consequence of a reform on higher education under the dictatorship of Augusto Pinochet, it became what is now known as Universidad de Santiago de Chile, with all activities centered in a single 340,000 m² campus in the capital Santiago. Wikipedia.


Mao L.,University of Santiago de Chile
Journal of Geophysical Research: Earth Surface | Year: 2012

Field measurements of sediment transport in gravel bed rivers often reveal hysteretic effects due to differences in sediment availability between the rising and falling limbs of a flood hydrograph. However, only a small number of flume studies have analyzed the dynamics of sediment transport during hydrographs. Three types of stepped hydrographs with contrasting durations and magnitudes are simulated here under sediment recirculation conditions. Bed load transport rate and grain size have been measured continuously. The dynamic behavior of the surface armor layer has been explored by analyzing digital photographs and laser scanner surveys of the bed surface taken during hydrographs. The results indicate that sediment transport during the falling limb was lower than during the rising limb in all of the three types of hydrographs. This reduction is more evident for the low-magnitude hydrographs. The grain size of the bed remained virtually constant throughout the hydrographs but the grain size of transported sediments exhibited a counterclockwise hysteresis. Also, a significant increase in the reference shear stress for sediment entrainment was measured during the falling limb of hydrographs. Additionally, a detailed analysis of partial transport dynamics of the bed surface sediments reveals a reduction in sediment mobility during the falling limb of the hydrographs. The difference in sediment entrainment and transport before and after the peak of the hydrographs appears to be caused by a change in the organization of the surface sediments. An analysis of detailed laser scan bed surveys reveals a phase of bed restructuring (lower vertical roughness, clast rearrangement) during the falling limb of hydrographs. Consequently, changes in the degree of organization and complexity of the bed surface are likely the cause of the reduced mobility of sediments, and thus of the reduced sediment transport rate, during the falling limb of the hydrographs. © 2012. American Geophysical Union. All Rights Reserved.


Castro-Rodriguez J.A.,University of Santiago de Chile
Journal of Allergy and Clinical Immunology | Year: 2010

Recurrent wheezing is a common problem in young children: approximately 40% of children wheeze in their first year of life. However, only 30% of preschoolers with recurrent wheezing still have asthma at the age of 6 years. Nevertheless, asthma, the most prevalent chronic disease in children, is difficult to diagnose in infants and preschoolers. This article reviews the importance of determining at an early age which infants/ preschoolers will have asthma later in life, analyzes the pros and cons of different predictive indices, and discusses the efficacy of the Asthma Predictive Index. (J Allergy Clin Immunol 2010; 126: 212-6.) © 2010 American Academy of Allergy, Asthma & Immunology.


Rodrigo G.J.,Hospital Central de las Fuerzas Armadas | Castro-Rodriguez J.A.,University of Santiago de Chile
Chest | Year: 2015

BACKGROUND: The role of tiotropium for the treatment of asthma has not yet been clearly defined. The aim of this systematic review was to assess the efficacy and safety of tiotropium in patients with asthma. METHODS: Randomized placebo-controlled trials were included. Primary outcomes were peak and trough FEV1 and morning and evening peak expiratory flow (PEF). RESULTS: Thirteen studies (4,966 patients) were included. Three different therapeutic protocols were identified. Tiotropium as an add-on to inhaled corticosteroids (ICSs) showed statistically and clinically significant increases in PEF (22-24 L/min) and FEV 1 (140-150 mL). Additionally, tiotropium decreased the rate of exacerbations (number needed to treat for benefit [NNTB], 36) and improved asthma control. The use of tiotropium in patients poorly controlled despite the use of medium to high doses of ICS was not inferior to salmeterol. Finally, the use of tiotropium as an add-on to ICS/salmeterol combination increased pulmonary function to a clinically significant magnitude, reduced asthma exacerbations (relative risk, 0.70; 95% CI, 0.53-0.94; P < .02; I2 = 0%; NNTB, 17), and improved asthma control compared with ICS/ salmeterol. Tiotropium was well tolerated, and no potential safety signals were observed. CONCLUSIONS: Tiotropium resulted noninferiorly to salmeterol and superiorly to placebo in patients with moderate to severe asthma who were not adequately controlled by ICS or ICS/ salmeterol. Major benefits were concentrated in the increase in lung function and in the case of patients with severe asthma, in the reduction of exacerbations. © 2015 American College of Chest Physicians.


Castro-Rodriguez J.A.,University of Santiago de Chile
Current Opinion in Allergy and Clinical Immunology | Year: 2011

Purpose of review: Recurrent wheezing is a common problem in young children. Recent findings: Approximately 40% of children wheeze in their first year of life. However, only 30% of preschoolers with recurrent wheezing still have asthma at the age of 6 years. Nevertheless, asthma, the most prevalent chronic disease in children, is difficult to diagnose in infants and preschoolers. Summary: We review the importance of determining at early age which infant/preschoolers will develop asthma later on life and discuss the utility of the Asthma Predictive Index. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.


Gonzalez J.,University of Santiago de Chile
Journal of Statistical Software | Year: 2014

Equating is a family of statistical models and methods that are used to adjust scores on two or more versions of a test, so that the scores from different tests may be used interchangeably. In this paper we present the R package SNSequate which implements both standard and nonstandard statistical models and methods for test equating. The package construction was motivated by the need of having a modular, simple, yet comprehensive, and general software that carries out traditional and new equating methods. SNSequate currently implements the traditional mean, linear and equipercentile equating methods, as well as the mean-mean, mean-sigma, Haebara and Stocking-Lord item response theory linking methods. It also supports the newest methods such as local equating, kernel equating, and item response theory parameter linking methods based on asymmetric item characteristic functions. Practical examples are given to illustrate the capabilities of the software. A list of other programs for equating is presented, highlighting the main differences between them. Future directions for the package are also discussed. © 2014 American Statistical Association. All rights reserved.

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