Prácticas de gestión tecnológica en la industria de la construcción: el caso de una empresa pública de ingeniería civil

En la actualidad, las empresas que quieren crecer tienen que desarrollar nuevos y mejores productos o servicios. Una forma de lograrlo es a través de la gestión tecnológica. En México existe un premio nacional que se otorga a las compañías que cuentan con sistemas eficientes de gestión que las hacen ser más competitivas. Dicho galardón lo han ganado organizaciones privadas en diversos sectores como los de telecomunicaciones, electrodomésticos y farmacéuticos. Sin embargo, las instituciones públicas y en particular las de la industria de la construcción no han recibido esa distinción. En un esfuerzo por determinar los niveles de uso y de importancia percibida de las "mejores prácticas" de gestión tecnológica en una empresa del gobierno dedicada a la ingeniería civil, se llevó a cabo una investigación. Los resultados revelan que aún existen oportunidades de mejora en el secto

Noise rectification in quasigeostrophic forced turbulence

We study the appearance of large scale mean motion sustained by stochastic forcing on a rotating fluid (in the quasigeostrophic approximation) flowing over topography. As in other noise rectification phenomena, the effect requires nonlinearity and absence of detailed balance to occur. By application of an analytical coarse graining procedure we identify the physical mechanism producing such effect: It is a forcing coming from the small scales that manifests in a change in the effective viscosity operator and in the effective noise statistical properties.Comment: 4 pages revtex, including 5 figures. Related material at http://www.imedea.uib.es/Nonlinear and http://www.imedea.uib.es/Oceanography Figure 4 replaced by a slightly better on

Life-Cycle Cost of Bridges on Seismic Zones for Risk Management

In this paper the acceptable failure probability and the risk of important bridges, located on seismic zones, are calculated throughout the expected cost of failure consequences. Also, the bridge expected life-cycle cost is formulated in terms of the bridge seismic hazard and the potential consequences of failure. These consequences include aspects arising from the physical loss of the bridge to the human casualties and economical cost of the loss of service, which are estimated in monetary terms. Current codes do not explicitly deal with this issue and in practice subjective estimations from experience are considered for some general cases. Bridge reliability is an essential component of risk and in this paper is estimated in a simplified way and applied to the structural types given in the examples. Monte Carlo simulation techniques are used to explicitly account for the uncertainties. Initial and failure cost curves are determined for all possible seismic intensities and expected life-cycle costs conditional to these intensities are obtained. The unconditional expected lifecycle cost is calculated by convolution of the conditional costs by the occurrence probabilities of these intensities, which are obtained from the seismic hazard curve of the given site. The procedure is illustrated throughout three reinforced concrete bridges located 1 on the soft soil of Mexico City and the other two on other sites with less seismic activity and different traffic volumes. The results may be extended to get risk management policies for bridges and to improve the current Mexican codes and to enhance the practices on bridge design and maintenance on seismic zones

Relevance of the study of metabolic profiles in sheep and goat flock. Present and future: A review

Current adoption of technical methods of the production systems and the genetic improvement of flocks’ productivity have led to the emergence of the well-known metabolic diseases or diseases linked to production. These disorders affect the health status of the flock, thereby generating strong economic losses in the livestock sector. The solution goes through the assessment of the ration, the characteristics of the facilities, the physiological state and the health of the flock, but also, assessing the health condition which is not always reflected in their body condition or feed intake. In field conditions, metabolic profiles could be considered as possible intermediate monitoring tool between animal production and nutrition, because they are able to express a(n) (im)balance between production requirements and feed intake. This information can be accessed by performing measurements and interpreting different blood parameters in a clinical context. Thus, the aim of this review is to offer current information about biochemical metabolic parameters in small ruminants, covering some influencing aspects related to sampling procedure, management and interpretation of results

Manejo sustentable del sitio en proyectos de arquitectura; criterios y estrategias de diseño

El presente trabajo consta del estudio y revisión de estrategias de diseño sustentable para el manejo del sitio de proyectos de arquitectura y de cómo podemos aprovechar de una mejor manera el entorno para beneficiar tanto al proyecto arquitectónico como al contexto urbano. El trabajo consta particularmente de recomendaciones de diseño arquitectónico sustentable para hacer una mejor selección y planeación del sitio, así como una mejor orientación y ubicación del edificio en el sitio; también se proponen conceptos generales para el manejo y cuidado del paisaje del sitio del proyecto, respetando los recursos naturales del lugar como aprovechamiento de agua, energía, disminución de islas de calor, aprovechamiento de materiales de construcción y aprovechamiento de los recursos bióticos y abióticos del lugar.El presente trabajo consta del estudio y revisión de estrategias de diseño sustentable para el manejo del sitio de proyectos de arquitectura y de cómo podemos aprovechar de una mejor manera el entorno para beneficiar tanto al proyecto arquitectónico como al contexto urbano. El trabajo consta particularmente de recomendaciones de diseño arquitectónico sustentable para hacer una mejor selección y planeación del sitio, así como una mejor orientación y ubicación del edificio en el sitio; también se proponen conceptos generales para el manejo y cuidado del paisaje del sitio del proyecto, respetando los recursos naturales del lugar como aprovechamiento de agua, energía, disminución de islas de calor, aprovechamiento de materiales de construcción y aprovechamiento de los recursos bióticos y abióticos del lugar

Phagocytic and pinocytic uptake of cholesterol in Tetrahymena thermophila impact differently on gene regulation for sterol homeostasis

The ciliate Tetrahymena thermophila can either synthesize tetrahymanol or when available, assimilate and modify sterols from its diet. This metabolic shift is mainly driven by transcriptional regulation of genes for tetrahymanol synthesis (TS) and sterol bioconversion (SB). The mechanistic details of sterol uptake, intracellular trafficking and the associated gene expression changes are unknown. By following cholesterol incorporation over time in a conditional phagocytosis-deficient mutant, we found that although phagocytosis is the main sterol intake route, a secondary endocytic pathway exists. Different expression patterns for TS and SB genes were associated with these entry mechanisms. Squalene synthase was down-regulated by a massive cholesterol intake only attainable by phagocytosis-proficient cells, whereas C22-sterol desaturase required ten times less cholesterol and was up-regulated in both wild-type and mutant cells. These patterns are suggestive of at least two different signaling pathways. Sterol trafficking beyond phagosomes and esterification was impaired by the NPC1 inhibitor U18666A. NPC1 is a protein that mediates cholesterol export from late endosomes/lysosomes in mammalian cells. U18666A also produced a delay in the transcriptional response to cholesterol, suggesting that the regulatory signals are triggered between lysosomes and the endoplasmic reticulum. These findings could hint at partial conservation of sterol homeostasis between eukaryote lineages.Fil: Hernandez, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Gabrielli, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Costa, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Uttaro, Antonio Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces

Multiclass determination of 66 organic micropollutants in environmental water samples by fast gas chromatography–mass spectrometry

A multiresidue method has been developed for quantification and identification of 66 multiclass priority organic pollutants in water by fast gas chromatography (GC) coupled to mass spectrometry (MS). Capabilities and limitations of single quadrupole mass spectrometer as detector in fast GC were studied evaluating the chromatographic responses in terms of sensitivity and chromatographic peak shapes, as they were influenced by scan time. The number of monitored ions in a selected ion monitoring (SIM) group strongly conditioned the scan time and subsequently the number of data points per peak. A compromise between peak shape and scan time was adopted in order to reach the proper conditions for quantitative analysis. An average of 10–15 points per peak was attained for most compounds, involving scan times between 0.1 and 0.22 s. The method was validated for mineral, surface, and groundwater. A solid-phase extraction pre-concentration step using C18 cartridges was applied. Four isotopically labeled standards were added to the samples before extraction and used as surrogates to ensure a reliable quantification. Analyses were performed by GC–MS in electron ionization mode, monitoring the three most abundant and/or specific ions for each compound and using the intensity ratios as a confirmatory parameter. With a chromatographic run of less than 10 min, SIM mode provided excellent sensitivity and identification capability due to the monitoring of three ions and the evaluation of their intensity ratio. Limits of detection below 10 ng/L were reached for most of the 66 compounds in the three matrices studied. Accuracy and precision of the method were evaluated by means of recovery experiments at two fortification levels (10 and 100 ng/L), obtaining recoveries between 70% and 120% in most cases and relative standard deviations below 20%. The possibilities of a simultaneous SIM scan method have also been explored for non-target qualitative analysis. The developed method has been applied to the analysis of surface water samples collected from the Mediterranean region of Spain

Comparison of Simple and Rapid Extraction Procedures for the Determination of Pesticide Residues in Fruit Juices by Fast Gas Chromatography–Mass Spectrometry

Three sample treatment methods, based on QuEChERS, solid-phase extraction (SPE) and solid-phase microextraction (SPME), were compared and evaluated in order to obtain the best conditions to determine pesticide residues in fruit juice by fast gas chromatography–mass spectrometry (single quadrupole GC-MS). Analysis were performed under selected ion monitoring, acquiring the three most abundant and/or specific ions for each analyte and using their relative intensity ratios as a confirmatory parameter. The 3 methodologies (QuEChERS, SPE and SPME) were validated taking 15 selected pesticides as model compounds, using commercial apple juice. QuEChERS procedure was based on the AOAC Official Method 2007.01, using acetonitrile (containing 1 % acetic acid) as extraction solvent and primary–secondary amine during the dispersive solid-phase extraction. Oasis hydrophilic–lipophilic balance cartridges were used for SPE, and polyacrylate fibers were used for direct immersion SPME procedure. Three isotopically labeled standards were added to the samples before extraction and used as surrogate standards. Validation parameters as recoveries, limits of detection, and limits of quantification (LOQ), as well as matrix effects and sample throughput, were obtained and compared for the three extraction procedures. QuEChERS was considered faster and led to the best quantitative results. In this way, validation was extended to up to 56 pesticides by applying QuEChERS in multi-fruit juice samples, obtaining LOQs ranging from 2 to 20 μg/L for most compounds. Accuracy and precision were evaluated by means of recovery experiments at two concentration levels (10 and 100 μg/L), obtaining recoveries between 70 and 120 % in most cases and relative standard deviations below 15 %. Finally, the QuEChERS method was applied to the analysis of commercial juices, including mango–apple, pineapple, grapefruit and orange

Práctica de la Gestión de proyectos en la industria de la construcción: un caso en el Estado de México (parte II)

El sector de la construcción contribuye sustancialmente al desarrollo de un país en virtud de que genera la infraestructura requerida por la sociedad para mejorar su calidad de vida. Esto pone de manifiesto la necesidad de diseñar herramientas para que los profesionales del ramo puedan administrar adecuadamente sus proyectos. Los libros y artículos hasta ahora escritos reportan distintas técnicas teóricas, pero son pocos los casos de estudio en los que se ilustra la aplicación de ellas. Esta situación impide que los practicantes tengan ejemplos útiles que les ayuden a implementar nuevas ideas para mejorar los procesos internos de sus compañías. En un esfuerzo por generar conocimiento en este sentido, se ha llevado a cabo un estudio en una empresa del Estado de México, tomando un ejemplo un proyecto sanitario en el cual se aplicaron empíricamente algunas herramientas teóricas de la gestión de proyectos