Diseño e implementación de un plan de mejoras para disminuir las devoluciones de productos de una fábrica de alimentos

El diseño e implementación de mejoras destinadas a la disminución de las devoluciones por parte de los clientes parte de un diagnóstico y comprobación de hipótesis. En la parte del diagnóstico, se realizó un análisis histórico de los datos donde se encontró posibles causas del problema; productos que más se devuelven, clientes que más los devuelven y diferentes tipos de problemas a lo largo de la cadena logística como mal paletizado, temperaturas inadecuadas etc. Una vez concluido con el diagnóstico, se procedió al planteamiento de hipótesis del problema, que fueron comprobadas a través de la investigación. Luego de definir las variables que causaban las devoluciones se definieron, bajo el uso de un diagrama de árbol, las causas raíces del problema. Estas causas generaron el diseño de 17 mejoras destinadas para corregir los problemas encontrados, mejoras que modifican diferentes procesos tanto operativos como administrativos y plantean diferentes tipos de control que buscan la disminución de todo tipo de devoluciones. Las mejoras fueron implementadas durante el mes de Octubre del 2003 y posteriormente evaluadas para medir el alcance de los objetivos y el ahorro efectivo obtenido

The Spitzer South Pole Telescope Deep Field Survey: Linking galaxies and halos at z=1.5

We present an analysis of the clustering of high-redshift galaxies in the recently completed 94 deg$^2$ Spitzer-SPT Deep Field survey. Applying flux and color cuts to the mid-infrared photometry efficiently selects galaxies at $z\sim1.5$ in the stellar mass range $10^{10}-10^{11}M_\odot$, making this sample the largest used so far to study such a distant population. We measure the angular correlation function in different flux-limited samples at scales $>6^{\prime \prime}$ (corresponding to physical distances $>0.05$ Mpc) and thereby map the one- and two-halo contributions to the clustering. We fit halo occupation distributions and determine how the central galaxy's stellar mass and satellite occupation depend on the halo mass. We measure a prominent peak in the stellar-to-halo mass ratio at a halo mass of $\log(M_{\rm halo} / M_\odot) = 12.44\pm0.08$, 4.5 times higher than the $z=0$ value. This supports the idea of an evolving mass threshold above which star formation is quenched. We estimate the large-scale bias in the range $b_g=2-4$ and the satellite fraction to be $f_\mathrm{sat}\sim0.2$, showing a clear evolution compared to $z=0$. We also find that, above a given stellar mass limit, the fraction of galaxies that are in similar mass pairs is higher at $z=1.5$ than at $z=0$. In addition, we measure that this fraction mildly increases with the stellar mass limit at $z=1.5$, which is the opposite of the behavior seen at low-redshift.Comment: 32 pages, 22 figures. Published in MNRA

Physically-sound simulation of low-velocity impact on fiber reinforced laminates

A high-fidelity virtual tool for the numerical simulation of low-velocity impact damage in unidirectional composite laminates is proposed. A continuum material model for the simulation of intraply damage phenomena is implemented in a numerical scheme as a user subroutine of the commercially available Abaqus finite element package. Delaminations are simulated using of cohesive surfaces. The use of structured meshes, aligned with fiber directions allows the physically-sound simulation of matrix cracks parallel to fiber directions, and their interaction with the development of delaminations. The implementation of element erosion criteria and the application of intraply and interlaminar friction allow for the simulation of fiber splits and their entanglement, which in turn results in permanent indentation in the impacted laminate. It is shown that this simulation strategy gives sound results for impact energies bellow and above the Barely Visible Impact Damage threshold, up to laminate perforation condition

The influence of sensor placement on in-situ ultrasound wave velocity measurement.

Ultrasound wave velocity was measured in 30 pieces of Spanish Scots pine (Pinus sylvestris L.), 90 x 140 mm in cross-section and 4 m long. Five different sensor placement arrangements were used: end to end (V0), face to opposite face, edge to opposite edge, face to same face and edge to same edge. The pieces were successively shortened to 3, 2 and 1 m, in order to obtain these velocities and their ratios to reference value V0 for different lengths and angles with respect to the piece axis for the crossed measurements. The velocity obtained in crossed measurements is lower than V0. A correction coefficient for crossed velocities is proposed, depending on the angle, to adjust them to the V0 benchmark. The velocities measured on a surface, are also lower than V0, and their ratio with respect to V0 is close to 0.97 for distances equal to or greater than 18 times the depth of the beam

Genetic variability and structure of an isolated population of Ambystoma altamirani, a mole salamander that lives in the mountains of one of the largest urban areas in the world

Amphibians are globally threatened by habitat loss and fragmentation; species within the order Ambystoma are not the exception, as there are 18 species of mole salamanders in México, of which 16 are endemic and all species are under some national or international status of protection. The mole salamander, Ambystoma altamirani is a microendemic species, which is distributed in central México, within the trans-Mexican volcanic belt, and is one of the most threatened species due to habitat destruction and the introduction of exotic species. Nine microsatellite markers were used to determine the genetic structure, genetic variability, effective population size, presence of bottlenecks and inbreeding coefficient of one population of A. altamirani to generate information which might help to protect and conserve this threatened species. We found two genetic subpopulations with significant level of genetic structure (FST = 0.005) and high levels of genetic variability (Ho = 0.883; He = 0.621); we also found a small population size (Ne = 8.8), the presence of historical (M = 0.486) and recent bottlenecks under IAM and TPM models, with a low, but significant coefficient of inbreeding (FIS = −0.451). This information will help us to raise conservation strategies of this microendemic mole salamander species

Assessing the Gene Content of the Megagenome: Sugar Pine (Pinus lambertiana).

Sugar pine (Pinus lambertiana Douglas) is within the subgenus Strobus with an estimated genome size of 31 Gbp. Transcriptomic resources are of particular interest in conifers due to the challenges presented in their megagenomes for gene identification. In this study, we present the first comprehensive survey of the P. lambertiana transcriptome through deep sequencing of a variety of tissue types to generate more than 2.5 billion short reads. Third generation, long reads generated through PacBio Iso-Seq have been included for the first time in conifers to combat the challenges associated with de novo transcriptome assembly. A technology comparison is provided here to contribute to the otherwise scarce comparisons of second and third generation transcriptome sequencing approaches in plant species. In addition, the transcriptome reference was essential for gene model identification and quality assessment in the parallel project responsible for sequencing and assembly of the entire genome. In this study, the transcriptomic data were also used to address questions surrounding lineage-specific Dicer-like proteins in conifers. These proteins play a role in the control of transposable element proliferation and the related genome expansion in conifers

Precipitation of Phosphate Minerals by Microorganisms Isolated from a Fixed-Biofilm Reactor Used for the Treatment of Domestic Wastewater

The ability of bacteria isolated from a fixed-film bioreactor to precipitate phosphate crystals for the treatment of domestic wastewater in both artificial and natural media was studied. When this was demonstrated in artificial solid media for crystal formation, precipitation took place rapidly, and crystal formation began 3 days after inoculation. The percentage of phosphate-forming bacteria was slightly higher than 75%. Twelve major colonies with phosphate precipitation capacity were the dominant heterotrophic platable bacteria growing aerobically in artificial media. According to their taxonomic affiliations (based on partial sequencing of the 16S rRNA), the 12 strains belonged to the following genera of Gram-negative bacteria: Rhodobacter, Pseudoxanthobacter, Escherichia, Alcaligenes, Roseobacter, Ochrobactrum, Agromyce, Sphingomonas and Paracoccus. The phylogenetic tree shows that most of the identified populations were evolutionarily related to the Alphaproteobacteria (91.66% of sequences). The minerals formed were studied by X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray microanalysis (EDX). All of these strains formed phosphate crystals and precipitated struvite (MgNH4PO4·6H2O), bobierrite [Mg3(PO4)2·8H2O] and baricite [(MgFe)3(PO4)2·8H2O]. The results obtained in this study show that struvite and spherulite crystals did not show any cell marks. Moreover, phosphate precipitation was observed in the bacterial mass but also near the colonies. Our results suggest that the microbial population contributed to phosphate precipitation by changing the media as a consequence of their metabolic activity. Moreover, the results of this research suggest that bacteria play an active role in the mineral precipitation of soluble phosphate from urban wastewater in submerged fixed-film bioreactors.This investigation was funded by the CTM 2009-11929-CO2-02 of the Spanish Ministerio de Educación y Ciencia

Experimental Analysis of the Multipactor Effect With RF Pulsed Signals

© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The main goal of this letter is the analysis of the multipactor effect within a coaxial waveguide excited by an RF pulsed signal. The variation of the multipactor RF voltage thresholdwiththe ON interval length of the pulse has been analyzed. To reach this aim, an in-house multipactor simulation code based on the Monte-Carlo algorithm has been implemented. The numerical simulations show that the multipactor RF voltage threshold increases as the ON pulse interval diminishes. In addition, an experiment was carried out to validate the proposed theoretical model, and demonstrating the excellent agreement between the theory and the experimental data. Finally, the results are compared with the 20-gap-crossing rule used in the space standard document (ECSS-E20-1A).The work of O. Monerris Belda was supported by the European Regional Development Fund. The review of this letter was arranged by Editor A. Ortiz-Conde.Gonzalez Iglesias, D.; Monerris Belda, Ó.; Diaz, M.; Gimeno Martinez, B.; Boria Esbert, VE.; Raboso García-Baquero, D. (2015). Experimental Analysis of the Multipactor Effect With RF Pulsed Signals. IEEE Electron Device Letters. 36(10):1085-1087. doi:10.1109/LED.2015.2468068S10851087361