How Do Immigrants Spend Their Time? The Process of Assimilation

Using 2004-2008 data from the American Time Use Survey, we show that sharp differences between the time use of immigrants and natives become noticeable when activities are distinguished by incidence and intensity. We develop a theory of the process of assimilation – what immigrants do with their time – based on the notion that assimilating activities entail fixed costs. The theory predicts that immigrants will be less likely than natives to undertake such activities, but conditional on undertaking them, immigrants will spend more time on them than natives. We identify several activities – purchasing, education and market work – requiring the most interaction with the native world, and these activities more than others fit the theoretical predictions. Additional tests suggest that the costs of assimilating derive from the costs of learning English and from some immigrants’ unfamiliarity with a high-income market economy. A replication using the 1992 Australian Time Use Survey yields remarkably similar results.time use, fixed costs, incidence, intensity

Special Issue on “Machining Dynamics and Parameters Process Optimization”

In 1907, F.W Taylor—the father of production engineering—exposed the fundamentals of modern machining and defined chatter as the most obscure and delicate of all problems facing the machinist [...

Additively manufactured MEMS multiplexed coaxial electrospray sources for high-throughput, uniform generation of core–shell microparticles

his study reports the first MEMS multiplexed coaxial electrospray sources in the literature. Coaxial electrospraying is a microencapsulation technology based on electrohydrodynamic jetting of two immiscible liquids, which allows precise control with low size variation of the geometry of the core–shell particles it generates, which is of great importance in numerous biomedical and engineering applications, e.g., drug delivery and self-healing composites. By implementing monolithic planar arrays of miniaturized coaxial electrospray emitters that work uniformly in parallel, the throughput of the compound microdroplet source is greatly increased, making the microencapsulation technology compatible with low-cost commercial applications. Miniaturized core–shell particle generators with up to 25 coaxial electrospray emitters (25 emitters cm−2) were fabricated via stereolithography, which is an additive manufacturing process that can create complex microfluidic devices at a small fraction of the cost per device and fabrication time associated with silicon-based counterparts. The characterization of devices with the same emitter structure but different array sizes demonstrates uniform array operation. Moreover, the data demonstrate that the per-emitter current is approximately proportional to the square root of the flow rate of the driving liquid, and it is independent of the flow rate of the driven liquid, as predicted by the theory. The core/shell diameters and the size distribution of the generated compound microparticles can be modulated by controlling the flow rates fed to the emitters.Instituto Tecnologico y de Estudios Superiores de Monterre

Importance of the construction of Critical Thinking in the process of preparing academic paper in higher education

Este artículo tiene como finalidad exponer la importancia de la construcción del Pensamiento Crítico en el proceso de elaboración de trabajos académicos en la Educación Superior. Se define como la habilidad que capacita al estudiante para hacer preguntas y juicios de valor; de tal manera que es una forma superior del pensamiento. Esta forma de abordaje de los problemas posibilita la generación de nuevas formas de pensar y actuar de manera amplia y estratégica, formulando conocimientos nuevos sin necesidad de seguir manuales, formatos preestablecidos y sobretodo siguiendo su propio razonamiento. Y por último, gracias a esta forma de pensar permite el empoderamiento intelectual para poder en último término transformar la realida

Improving Stability Prediction in Peripheral Milling of Al7075T6

Chatter is an old enemy to machinists but, even today, is far from being defeated. Current requirements around aerospace components call for stronger and thinner workpieces which are more prone to vibrations. This study presents the stability analysis for a single degree of freedom down-milling operation in a thin-walled workpiece. The stability charts were computed by means of the enhanced multistage homotopy perturbation (EMHP) method, which includes the helix angle but also, most importantly, the runout and cutting speed effects. Our experimental validation shows the importance of this kind of analysis through a comparison with a common analysis without them, especially when machining aluminum alloys. The proposed analysis demands more computation time, since it includes the calculation of cutting forces for each combination of axial depth of cut and spindle speed. This EMHP algorithm is compared with the semi-discretization, Chebyshev collocation, and full-discretization methods in terms of convergence and computation efficiency, and ultimately proves to be the most efficient method among the ones studied.The authors wish to acknowledge the financial support received from HAZITEK program, from the Department of Economic Development and Infrastructures of the Basque Government and from FEDER funds. Additional support was provided by the Tecnologico de Monterrey, through the Research Group in Nanomaterials and Devices Design

How Do Immigrants Spend Time?: The Process of Assimilation

Using 2004-2008 data from the American Time Use Survey, we show that sharp differences between the time use of immigrants and natives become noticeable when activities are distinguished by incidence and intensity. We develop a theory of the process of assimilation—what immigrants do with their time—based on the notion that assimilating activities entail fixed costs. The theory predicts that immigrants will be less likely than natives to undertake such activities, but conditional on undertaking them, immigrants will spend more time on them than natives. We identify several activities—purchasing, education and market work—as requiring the most interaction with the native world, and these activities more than others fit the theoretical predictions. Additional tests suggest that the costs of assimilating derive from the costs of learning English and from some immigrants’ unfamiliarity with a high-income market economy. A replication using the 1992 Australian Time Use Survey yields remarkably similar results.

Evaluación del posicionamiento preciso a través de los receptores GPS LEA-6T, NEO-M8T y ZED-F9P de bajo costo

Se comparó el posicionamiento obtenido en dos casos de estudios dependientes de las distancias (~31 y ~4.9 Km) a través del método estático mediante el uso de receptores de bajo costo de simple (LEA-6T y NEO-M8T) y doble frecuencia (ZED-F9P); tomando como referencia un receptor de orden geodésico Geomax Zenith 25. Asimismo, el posicionamiento fue evaluado con a la normativa vigente en México para el Circulo de Error Probable (CEP) y Exactitud Posicional Vertical (EPV) con una incertidumbre del 95%. Seencuentran discrepancias entre coordenadas para un mismo punto en el sistema ENU, valores mínimos de ~ 2 mm y ~ 10 mm, para una distancia ~31 y ~4.9 Km, respectivamente, obteniendo el mejor resultado con el receptor de una frecuencia LEA-M8T para la distancia de ~31 km; para el caso ~4.9 km se presenta con el receptor ZED-F9P en conjunto con una antena de orden Geodésico. Por otro lado, los resultados muestran un grado de cumplimiento en el posicionamiento de los receptores de bajo costo favorable donde; se obtienen valores de 8 mm de variación máxima para CEP; para EPV al 95% de confiabilidad, 1 cm de discrepancia. Presentando los mejores resultados los receptores LEA-6T y NEO-M8T, caso ~31 km, en cuanto a CEP y EPV.   A comparative study between the positioning obtained in two case studies depending on distances (~31 and ~4.9 km) was carried out through the static method of survey using the low-cost receivers of single (LEA-6T and NEO-M8T) and double frequency (ZED-F9P). The reference was taken as Geomax Zenith 25 geodetic order receiver. The positioning was evaluated with the current regulations in Mexico for the Circle of Probable Error (CEP) and Vertical Positional Accuracy (EPV) with an uncertainty of 95%. The discrepancies between coordinates for the same point in the ENU system were found to be the minimum values of ~ 2 mm and ~ 10 mm for a distance of ~31 and ~4.9 Km, respectively. The best results were obtained with the NEO-M8T single frequency receiver for the distance of ~31 km and for the distance of ~4.9 km, it is presented with the ZED-F9P receiver in conjunction with a geodetic antenna. Whereas on the other hand, the results show a degree of compliance in the positioning of low-cost receivers wherein the variation values of a maximum of 8 mm are obtained for CEP and for EPV 1 cm discrepancy was observed at 95% reliability. The LEA-6T and NEO-M8T receivers presented the best results for the case of ~31 km, in terms of CEP and EPV

Desarrollo de una aplicación web para la gestión de comandas en restaurantes

El objetivo principal de este proyecto es el diseño e implementación de una aplicación web, que denominaremos Note The Commands. Se trata de una aplicación web que permite gestionar y administrar las comandas de un restaurante de manera sencilla y ágil. Debido a la poca experiencia en el sector de la hostelería, así como en su gestión y administración, el proyecto se ha desarrollado atendiendo las necesidades de un cliente en concreto. Además de las peticiones del cliente hemos realizado un estudio funcional de las diferentes aplicaciones existentes para nutrirnos de más información para desarrollar una buena y completa aplicación web. Al comienzo del proyecto se han realizado un par de reuniones con el cliente para sobre todo para la captura de los requisitos tanto funcionales como no funcionales, en cuanto al diseño de la aplicación se concretó con el cliente que fuese libre asegurándonos de que la interfaz sea sencilla e intuitiva para facilitar su uso a todas las personas incluso aquellas que no disponen de grandes conocimientos en navegación web. La herramienta que hemos desarrollado esta implementada en el lenguaje de programación Ruby empleando el framework Rails. Se trata de una de las herramientas más utilizadas en el desarrollo web en estos momentos y uno de los más sencillos de aprender. En cuanto a la base de datos hemos utilizado MySQL. Finalmente, una vez implementado toda la funcionalidad hemos realizado un proceso de QA, esto es, hemos asegurado la calidad del software mediante un conjunto de pruebas unitarias y de integración para verificar y validar que los resultados obtenidos son los esperados.The main objective of this project is the design and implementation of a web application called Note The Commands. It is a web application to guarantee the management and administration of restaurant's commands in a simple and effective way. Due to the lack of experience of the author in the hospitality industry, as well as in its management and administration, the project has been developed taking care of the necessity of a specific client. In addition to the client's requests we have made a functional study of the different existing applications for more information to develop a good and comprehensive web application. At the beginning of the project a couple of meetings were carried out with the client. The purpose of these meetings was to capture both functional and non functional requirements, as well as the design of the application that was concreted with the client. A mayor goal was fixed: the application should assure that the interface will be simple and intuitive to facilitate its use to people with not a great knowledge in web browsing. Ruby on Rails (RoR) was the chosen framework to develop the web application. Nowadays, RoR is the mostly used tool in web development and one of the simplest to learn. Additionally, a cost-effective database solution was implemented using MySQL. Finally, the application was validated with a throughout Software Quality Assurance (QA) process. Therefore, sets of unit tests and integration were implemented to verify and validate that the results obtained should be the expected

Statistical modeling of oscillating biological networks for structure inference and experimental design

Oscillations lie at the core of many biological processes, from the cell cycle, to circadian oscillations and developmental processes. They are essential to enable organisms to adapt to varying conditions in environmental cycles, from day/night to seasonal. Transcriptional regulatory networks are one of the mechanisms behind these biological oscillations. One of the main problems of computational systems biology is elucidating the interaction between biological components. A common mathematical abstraction is to represent these interactions as networks whose nodes are the reactive species and the interactions are edges. There is abundant literature dealing with the reconstruction of the network structure from steady-state gene expression measurements; still, there are lots of advancements to be made because of the complex nature of biological systems. Experimental design is another obstacle to overcome; we wish to perform experiments that help us best define the network structure according to our current knowledge of the system. In the first chapters of this thesis we will focus on reconstructing the network structure of biological oscillators by explicitly leveraging the cyclical nature of the transcriptional signals. We present a method for reconstructing network interactions tailored to this special but important class of genetic circuits. The method is based on projecting the signal onto a set of oscillatory basis functions. We build a Bayesian hierarchical model within a frequency domain linear model in order to enforce sparsity and incorporate prior knowledge about the network structure. Experiments on real and simulated data show that the method can lead to substantial improvements over competing approaches if the oscillatory assumption is met, and remains competitive also in cases it is not. Having defined a model for gene expression in oscillatory systems, we also consider the problem of designing informative experiments for elucidating the dynamics and better identify the model. We demonstrate our approach on a benchmark scenario in plant biology, the circadian clock network of Arabidopsis thaliana, and discuss the different value of three types of commonly used experiments in terms of aiding the reconstruction of the network. Finally we provide the architecture and design of a software implementation to plug in statistical methods of gene expression inference and network reconstruction into a biological data integration platform

Drug prescription clusters in the UK Biobank: An assessment of drug-drug interactions and patient outcomes in a large patient cohort

In recent decades, there has been an increase in polypharmacy, the concurrent administration of multiple drugs per patient. Studies have shown that polypharmacy is linked to adverse patient outcomes and there is interest in elucidating the exact causes behind this observation. In this paper, we are studying the relationship between drug prescriptions, drug-drug interactions (DDIs) and patient mortality. Our focus is not so much on the number of prescribed drugs, the typical metric in polypharmacy research, but rather on the specific combinations of drugs leading to a DDI. To learn the space of real-world drug combinations, we first assessed the drug prescription landscape of the UK Biobank, a large patient data registry. We observed distinct drug constellation patterns driven by the UK Biobank participants' disease status. We show that these drug prescription clusters matter in terms of the number and types of expected DDIs, and may possibly explain observed differences in health outcomes