Efectos de la aglomeración y los encadenamientos industriales en el patrón de crecimiento manufacturero en México

La economía mexicana experimentó un cambio regional de la localización manufacturera en el periodo de 1980 a 2003, lo que modificó el patrón de concentración regional industrial. En este contexto, la frontera norte y los estados alrededor de la Ciudad de México y el Estado de México presentaron mayor crecimiento. Mediante un modelo econométrico, basado en la técnica del método generalizado de momentos, se evalúa el impacto de los encadenamientos industriales, la aglomeración y la distancia en la localización de las empresas manufactureras. Las estimaciones econométricas muestran evidencia de dispersión de la industria y debilitamiento de las relaciones intra-industriales, las economías de escala y los encadenamientos

Determination of biosorption mechanism in biomass of agave, using spectroscopic and microscopic techniques for the purification of contaminated water

[Abstract] Lead (Pb2+) and copper (Cu2+) are polluting metals due to their toxicity; however, the extraction of these metals is essential for economic development, so it is important to look for efficient and low-cost alternatives that can remove heavy metals from the various bodies of water. One of the alternatives used in this work is biosorption, for which an agroindustrial waste (epidermis from Agave atrovirens) was used to evaluate the affinity of removal of lead and copper in aqueous solutions; in addition, spectroscopy and microscopy techniques were used to elucidate and corroborate the removal and affinity capacity of the agave epidermis for both metals studied. The optimal pH value for the removal of both metals was 3. The adsorption isotherms yielded a qmax of 25.7 and 8.6 mg/g for lead and copper, respectively. Adjusting to the Langmuir-Freundlich model, the adsorption kinetics were pseudo-second order, and it was found that the equilibrium time was at 140 min. The spectroscopy and microscopy analyses corroborated the affinity between metals and functional groups of the agave, as well as with the elemental analysis, which reported 17.38% of lead and 4.25% of copper.[Resumen] El plomo (Pb2+) y el cobre (Cu2+) son metales contaminantes debido a su toxicidad; sin embargo, la extracción de estos metales es indispensable para el desarrollo económico, por lo que es importante buscar alternativas eficientes y de bajo costo que puedan remover metales pesados de los diversos cuerpos de agua. Una de las alternativas utilizadas en este trabajo es la biosorción, para la cual se utilizó un residuo agroindustrial (epidermis de Agave atrovirens), para evaluar la afinidad de remoción del plomo y cobre en soluciones acuosas; adicionalmente, se emplearon técnicas de espesctroscopía y microscopía que permitieron elucidar y corroborar la capacidad de remoción y afinidad que tuvo la epidermis de A. atrovirens para ambos metales estudiados. El valor óptimo de pH para la remoción de ambos metales fue 3. Las isotermas de adsorción arrojaron una qmax de 25.7 y 8.6 mg/g para el plomo y cobre, respectivamente. Ajustando al modelo de Langmuir-Freundlich, las cinéticas de adsorción resultaron de pseudo-segundo orden, se encontró que el tiempo de equilibrio es a los 140 min. El análisis espectroscópico y microscópico, corroboró la afinidad entre metales y grupos funcionales del agave, así como con el análisis elemental, el cual reportó 17.38% de plomo y 4.25% de cobre

Endogenous Antioxidants: A Review of their Role in Oxidative Stress

Oxidative stress (OxS) constitutes a disturbance caused by an imbalance between the generation of free radicals and antioxidant system, which causes damage to biomolecules. This, in turn, may lead the body to the occurrence of many chronic degenerative diseases. Therefore, it is very important to know the functioning of those endogenous (and exogenous) antioxidants systems to prevent such diseases. Due to evolutionary conditions in living beings, among other functions have been developed and selected defense systems against the deleterious action of free radicals. Such systems are intrinsic in cells (at level intracellular and extracellular) and act together with the dietary exogenous antioxidants. All these antioxidant systems have very important role in preserving the oxide/reduction equilibrium in the cell. To understand the role of the transcription factor Nrf2 in regulating the processes of antioxidant defense, it must also know the role of many of the endogenous antioxidants that occur because of its activation. Therefore, this chapter makes a literature review of the most important general aspects of endogenous antioxidant systems, which will provide another point of view from which to approach the study and treatment of many chronic degenerative diseases, such as diabetes, hypertension, and Parkinson

Electrolytic Cell Applied for the Breakdown of Endocrine Disrupting Drugs in Aqueous Tributaries

In this chapter, we report previous results about advances of an electrolysis process developed for breakdown of endocrine disrupting drugs in aqueous media. The objective is to achieve the breakdown of two drugs: trimethoprim and a mixture of clavulanic acid-amoxicillin (1:7) with an electrolytic cell by means of oxidization-reduction reactions. The evaluation of the process was carried out using spectrometry techniques UV-Vis, thin layer chromatography (TLC), chemical oxygen demand (COD), and total organic carbon (TOC). Handcrafted mineral carbon electrodes doped with titanium dioxide were designed, platinum and copper wires were placed, and a potassium hydroxide solution was used as electrolyte. The electrolyte, being an alkaline salt, allows the transport of charges from one side to the other, and electrode doped with titanium dioxide is used in order to help the electronic transfer, and the mineral carbon, having a strong affinity for organic and non-polar compounds, performs an adsorption process. Results from several performed assays showed that after 1 hour of treatment, it can be seen the breakdown of the drugs present in a synthetic wastewater solution

ECG study in practical labs for biomedical engineering training

Non-invasive biomedical measurements are one of the most important technological contributions whitin the biomedical engineering field. On this paper, a dual laboratory session student oriented is designed to simulate and implement a cardial signal monitor. During the first session, ORCAD PSpice software is used to simulate the whole process. The students can acquire knowledge on the process by configuring and running both the instrumentation amplifier and a passive filter to improve the signal quality. The second session requires from the student basic laboratory skills to use a specific printed circuit board (PCB) to measure its very own cardiac potential. As a result, from this session, the student can visualize the ECG signal acquired directly on the laboratory oscilloscope

DIAGNÓSTICO DE LESIONES BUCALES EN ALGUNAS LOCALIDADES DE PORTOVIEJO, ECUADOR

Oral cancer is a global health problem with increasing incidence and mortality rates, which is why screening programs have been implemented for the population in some countries. On the other hand, the presence of the most relevant risk factors for these diseases in the population of Manabi Province, Ecuador is recognized, especially the consumption of alcoholic beverages, smoking, high insolation, characteristic of the region as a protective factor of these pathologies. The objective of the work was to diagnose oral lesions in some localities of Portoviejo, Ecuador. An exploratory descriptive epidemiological study was carried out during the period 2013 to 2016. The study population in the first stage was the general population of the parishes of 18 de Octubre, Riochico, San Placido, Crucita, Colón, of the San Pablo sector, of the military fort Manabí, Ecuador, and the dental clinics of the Universidad San Gregorio de Portoviejo. The most relevant risk factors for the population studied were the consumption of alcoholic beverages, smoking, sun exposure and the use of ill-fitting prostheses. The diagnostic results of the studied population show leukoplakia with 29 cases and squamous cell carcinoma of the oral cavity with nine cases. It is concluded that the high prevalence of lesions such as oral cancer found shows the importance of including the systematic examination of the oral cavity in dental practice, a fact that can drastically reduce the incidence and prevalence of oral cancer.El cáncer bucal es un problema de salud global con una incidencia y tasas de mortalidad en aumento por lo cual se han implementado programas de cribaje para la población en algunos países. Por otra parte, es reconocida la presencia de los factores de riesgo de mayor relevancia para estas enfermedades en la población de la Provincia Manabí, Ecuador especialmente el consumo de bebidas alcohólicas, el hábito de fumar, la alta insolación, característica de la región como factor protector de estas patologías. El objetivo del trabajo fue diagnosticar lesiones bucales en algunas localidades de Portoviejo, Ecuador. Se realizó un estudio epidemiológico descriptivo exploratorio, durante el período 2013 hasta 2016. La población de estudio en la primera etapa fueron la población general de las parroquias 18 de Octubre, Riochico, San Plácido, Crucita, Colón, del sector San Pablo, del fuerte militar Manabí, Ecuador y de las clínicas odontológicas de la Universidad San Gregorio de Portoviejo. Se identificaron como factores de riesgo más relevantes, para la población estudiada, el consumo de bebidas alcohólicas, el hábito de fumar, la exposición solar y el uso de prótesis mal ajustadas. Los resultados diagnósticos de la población estudiada muestran la leucoplasia con 29 casos y Carcinoma epidermoide de cavidad bucal en nueve casos. Se concluye que la alta prevalencia de lesiones como de cáncer bucal hallada muestran la importancia de incluir en la práctica odontológica el examen sistemático de la cavidad oral, hecho que puede disminuir drásticamente la incidencia y prevalencia del cáncer bucal

Implementación y configuración bajo nethserver solucionando necesidades especificas con GNU/Linux

Este articulo es presentado para demostrar a través de una serie de imágenes la instalación y configuración de GNU/Linux Nethserver, siendo este un sistema operativo una base para disponer de los servicios de infraestructura IT. Se realiza una configuración previa de Nethserver y red, para el desarrollo de distintas temáticas que manejan temas como DHCP, DNS y Controlador de dominio, Proxy, Cortafuegos, File Server y Print Server, y por ultimo VPN. En la ejecución de estos temas se instalaron y configuraron aplicaciones fundamentales para el desarrollo de estas y se obtuvieron resultados favorables entorno a lo solicitado; de esta manera dejando en evidencia unos breves escritos los cuales detallan paso a paso el desarrollo.This article is presented to demonstrate through a series of images the installation and configuration of GNU/Linux Nethserver, this being an operating system that is the basis for having IT infrastructure services. A prior configuration of Nethserver and network is carried out, for the development of different themes that handle topics such as DHCP, DNS and Domain Controller, Proxy, Firewall, File Server and Print Server, and finally VPN. In the execution of these topics, fundamental applications for their development were installed and configured and favorable results were obtained in the requested environment; in this way revealing some brief writings which detail the development step by step

A Comparative Study of Physical and Chemical Processes for Removal of Biomass in Biofilters

After 6 months of operation a long-term biofilter was stopped for two weeks and then it was started up again for a second experimental period of almost 1.3 years, with high toluene loads and submitted to several physical and chemical treatments in order to remove excess biomass that could affect the reactor’s performance due to clogging, whose main effect is a high pressure drop. Elimination capacity and removal efficiency were determined after each treatment. The methods applied were: filling with water and draining, backwashing, and air sparging. Different flows and temperatures (20, 30, 45 and 60 °C) were applied, either with distilled water or with different chemicals in aqueous solutions. Treatments with chemicals caused a decrease of the biofilter performance, requiring periods of 1 to 2 weeks to recover previous values. The results indicate that air sparging with pure distilled water as well as with solutions of NaOH (0.01% w/v) and NaOCl (0.01% w/v) were the treatments that removed more biomass, working either at 20, 30 or 45 °C and at relatively low flow rates (below 320 L h−1), but with a high biodegradation inhibition after the treatments. Dry biomass (g VS) content was determined at three different heights of the biofilter in order to carry out each experiment under the same conditions. The same amount of dry biomass when applying a treatment was established so it could be considered that the biofilm conditions were identical. Wet biomass was used as a control of the biofilter’s water content during treatments. Several batch assays were performed to support and quantify the observed inhibitory effects of the different chemicals and temperatures applied

Environmental impact assessment of chicken meat production via an integrated methodology based on LCA, simulation and genetic algorithms

This study performed a Life Cycle Assessment (LCA) to evaluate the environmental impact of chicken meat production from a Mexican case study, with a “cradle-to-slaughterhouse gate” approach. To overcome the LCA's limitations and provide a more holistic picture of the system, simulation and artificial intelligence techniques were integrated. First, raw material/energy requirements were obtained from the case study and simulated using Process simulation (PS) and Monte Carlo (MC) simulation to estimate the emissions and quantify their uncertainty. Then, IMPACT 2002 + was used to calculate the overall impact using Ecoinvent and LCA Food databases. The results highlight that chicken farms are the main factors responsible for the environmental impacts assessed, where feed production (use of chemicals and energy requirements) and on-farm emissions (organic waste decomposition) are the main contributors. Concerning the slaughterhouse, the energy production (electricity and steam) and the cooling-related activities present a significant impact. Afterwards, three impact allocation procedures (mass method, neural networks, and stepwise regression) were tested, showing similar results. Finally, a multiobjective optimization model based on a Genetic Algorithm was applied looking to minimize the environmental impacts and maximize the economic benefits. The selected alternative achieved a reduction of 15.14% per functional unit at the environmental indicators. The results encourage the use of support techniques for LCA to perform a reliable assessment and an environmental/economic optimization of the system