112 research outputs found
Diagnóstico operativo empresarial – Agrícola del Chira S.A.
El objetivo principal de la presente investigación es realizar el Diagnóstico Operativo
Empresarial de Agrícola del Chira, perteneciente al Grupo Romero, esta consta de quince
capítulos en los cuales se incluye, además del análisis de las operaciones de Agrícola del
Chira, una serie de recomendaciones acerca de oportunidades de mejora en el proceso
productivo de la caña de azúcar, en donde se pueden generar ahorros y obtener ganancias
adicionales en la operación.
De esta manera tenemos el capítulo I en donde se hace una descripción somera de la
forma en que opera Agrícola del Chira dentro del holding Caña Brava. En el capítulo II se
hace una indagación respecto al marco teórico existente sobre el tema de gerencia de
operaciones. Los capítulos III y IV relatan la historia de cómo el grupo Romero, de manera
pionera, tomo decisión de ir adelante con un proyecto innovador, ya en los capítulos
subsiguientes se verifica una análisis exhaustivo de cada proceso dentro de la empresa y al
final de cada capítulo realizamos propuestas de mejora y conclusiones; en ellas debemos
entender como ahorro el no incurrir en el mismo gasto cada año y como beneficio, la utilidad
lograda después de una inversión.
Básicamente, la estrategia del presente DOE es dar un valor agregado al producto,
aportando beneficios, los cuales se verán reflejados en el primer año por un monto de 1, 052,794.60; y generando ahorros
por un monto de 433,705.20 en el segundo año y a partir
del tercer año un monto de 32,338.00 and from the second
year with an amount of
328,535.20 in the first year, of 350,535.20Tesi
Can statistical methods optimize complex multicomponent mixtures for sintering ceramic granular materials? A case of success with synthetic aggregates
The relationship between the proportions of multicomponent mixtures with the technological properties of ceramic granular materials (synthetic aggregates) has been studied using statistical methods. The four phases involved in the formulations have been: kaolin (K) as aluminosilicate source; cork powder (C) as organic carbon source; sodium carbonate (N) as flux and pyrite (P) as source of iron and sulfur. The Mixture Experiments - Design of Experiments (ME-DOE) has been the statistical methodology applied from the initial configuration of the 36 starting formulations to the final validation of the models and optimums. After granulation, artificial aggregates have been obtained by sintering in a rotary kiln, and their main technological properties have been determined. Bloating index (BI), particle density (ρrd), water absorption (WA24) and crushing strength (S) were selected as the four key characteristics to be modeled and optimized, using response surface and effect plots to assess the effect of K, C, N and P on such properties. 32 out of 36 starting varieties met the density criteria for lightweight aggregates. In the optimum formulations obtained, the minimum percentage of K was 83 wt%, so that the variations in the percentages of P, C and N were the critical variables for determining the final properties of the aggregate. The contrast between experimental and estimated data has shown that the models fit adequately, indicating that this type of approach may have enormous potential for future research on artificial aggregates and other ceramic materialsThis research was conducted as a part of the ECO-MET-AL Project, PID2019-109520RB-I00 / AEI / 10.13039/501100011033, “Can industrial and mining metalliferous wastes produce green lightweight aggregates? Applying the Circular Economy” funded by the Spanish Ministry of Science, Innovation and Universities and ERDF funds, framed in the “Ayudas a “Proyectos I + D + i" en el marco de los Programas Estatales de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I + D + i y de I + D + i orientada a los Retos de la Sociedad, Convocatoria 2019”. Thanks also to the SCAI of the University of Jaén, the University of Castilla-La Mancha and the University of Málaga for their service
Deep-sea habitat characterization using acoustic data and underwater imagery in Gazul mud volcano (Gulf of Cádiz, NE Atlantic)
Gazul is the shallowest mud volcano (MV) within the Shallow Field of Fluid Expulsion (SFFE) of the northeastern Gulf of Cádiz (NE Atlantic; 300–1200 m depth). The SFFE represents an important geo- and biodiversity area that was designated as a Site of Community Importance under the European Habitats Directive in 2014. In this study, geological features, habitats and associated biodiversity, as well as anthropogenic impacts, were characterized at Gazul MV from underwater imagery and multibeam bathymetry. Multivariate methods using the Bray-Curtis similarity index identified six main habitats, each of which harbored a characteristic faunal assemblage that included: (1) sandy ripple bottoms typified by the actiniarian Actinauge richardi; (2) sandy, muddy, coarse sand and bioclastic bottoms dominated by the solitary coral Flabellum chunii; (3) coarse sand and bioclastic bottoms, together with soft sediments covered by scattered methane-derived authigenic carbonates (MDACs) (mixed bottoms), characterized by the echinoid Cidaris cidaris; (4) hard bottoms comprising MDACs dominated by a wide variety of sponges and gorgonians; (5) coral-rubble bottoms typified by the presence of colonial scleractinian communities dominated by Madrepora oculata; and (6) mixed bottoms characterized by the presence of a styelid ascidian. Slope and water depth were the main factors explaining assemblages’ distribution, which was also supported by the presence of MDACs such as slabs, crusts and chimneys on the seafloor, as well as by the geomorphologic diversity of Gazul MV. The results highlight Gazul MV as an eco-biologically important area harboring different vulnerable marine ecosystem (VME) elements with indicator taxa such as scleractinians, sponges, gorgonians and black corals. ROV images revealed abandoned or lost fishing gears and marine debris on the seafloor, indicating anthropogenic impacts in Gazul MV and adjacent areas. Indeed trawling fisheries activities have also been detected in Vessel Monitoring System datasets. A fishery restricted area is recommended in Gazul MV due to the occurrence of diverse VMEs and species included in different conservation directives and conventions.Postprin
Mitochondrial Na+ controls oxidative phosphorylation and hypoxic redox signalling
All metazoans depend on O2 delivery and consumption by the mitochondrial oxidative phosphorylation (OXPHOS) system to produce energy. A decrease in O2 availability (hypoxia) leads to profound metabolic rewiring. In addition, OXPHOS uses O2 to produce reactive oxygen species (ROS) that can drive cell adaptations through redox signalling, but also trigger cell damage1–4, and both phenomena occur in hypoxia4–8. However, the precise mechanism by which acute hypoxia triggers mitochondrial ROS production is still unknown. Ca2+ is one of the best known examples of an ion acting as a second messenger9, yet the role ascribed to Na+ is to serve as a mere mediator of membrane potential and collaborating in ion transport10. Here we show that Na+ acts as a second messenger regulating OXPHOS function and ROS production by modulating fluidity of the inner mitochondrial membrane (IMM). We found that a conformational shift in mitochondrial complex I during acute hypoxia11 drives the acidification of the matrix and solubilization of calcium phosphate precipitates. The concomitant increase in matrix free-Ca2+ activates the mitochondrial Na+/Ca2+ exchanger (NCLX), which imports Na+ into the matrix. Na+ interacts with phospholipids reducing IMM fluidity and mobility of free ubiquinone between complex II and complex III, but not inside supercomplexes. As a consequence, superoxide is produced at complex III, generating a redox signal. Inhibition of mitochondrial Na+ import through NCLX is sufficient to block this pathway, preventing adaptation to hypoxia. These results reveal that Na+ import into the mitochondrial matrix controls OXPHOS function and redox signalling through an unexpected interaction with phospholipids, with profound consequences in cellular metabolism
Environmental, fishing and benthic linkage in the mud volcano field of the Spanish margin of the Gulf of Cádiz
The Gulf of Cadiz is located in the boundary of two lithospheric plates, this tectonic activity
promote fluid rich hydrocarbon emissions from subsurface reservoirs and the formation of several
mud volcanoes. The seabed and sedimentological heterogeneity, the complex oceanographic
circulation, and the low fishing activity in certain areas may promote high biodiversity and complex
habitats (habitat 1170 and 1180, Natura 2000). Environmental variables (fishing activity, substrate
types, near bottom currents) and fauna collected with beam-trawl have been compared for several
mud volcanoes and adjacent bottoms in order to understand the spatial distribution of both habitats
and environmental/anthropogenic variables. The faunistic samples yielded high abundances,
biomass and species richness in Gazul, Pipoca and Chica but low ones in Anastasya. In relation to
environmental variables and fisheries activity, there is a strong correlation with the substrate type,
depth, salinity and near-bottom current as primary variables influencing the distribution of habitats
of different mud volcanoes. In this context, high species richness, abundance and biomass was found
in areas with authigenic carbonates, coarse sediments, high near-bottom current speed, low
salinities and low fishing activity.Versión del edito
Vulnerable marine ecosystems and biological features of Gazul mud volcano (Gulf of Cádiz): A contribution towards a potential "Gulf of Cádiz" EBSA
The Gulf of Cádiz (GoC) represents an area of socioeconomic and scientific importance for oceanographic, geological and biological processes. An interesting feature of the GoC is the presence of a large amount of mud volcanoes (MVs) and diapirs that display different seepage, seabed types, oceanographic settings and biological communities. Detailed exploration of some MVs is still needed for detecting Vulnerable Marine ecosystems (VMEs) that seem to be rare in other areas of the GoC, improving the current knowledge on its biodiversity and ecological attributes. During different expeditions (MEDWAVES-ATLAS, INDEMARES-CHICA 0610 & 0412 and ISUNEPCA 0616) carried out in different years, biological samples and videos were obtained in Gazul MV (Spanish Margin of the GoC). The study of those samples and videos has revealed the presence of several ecologically important VMEs (e.g. 3 species of reef framework-forming corals, coral gardens including solitary scleractinians, gorgonians and antipatharians, as well as deep-sea sponge aggregations and chemosynthesis-related structures) and a large number of species occurring in this MV, including new records for the European margin, threatened species and non-previously described species. The combination of different environmental and anthropogenic factors allowed the present-day persistence of these VMEs in the GoC. Some of Gazul MV biological and ecological attributes fit several criteria of the Convention on Biological Diversity for EBSA description (e.g. 1,3,4,6) that, together with those of other areas of the GoC, may contribute to the future potential nomination of an EBSA in this area of the NE Atlantic
Lo glocal y el turismo. Nuevos paradigmas de interpretación.
El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global
Immune and spermatogenesis-related loci are involved in the development of extreme patterns of male infertility
We conducted a genome-wide association study in a large population of infertile men due to unexplained spermatogenic failure (SPGF). More than seven million genetic variants were analysed in 1,274 SPGF cases and 1,951 unaffected controls from two independent European cohorts. Two genomic regions were associated with the most severe histological pattern of SPGF, defined by Sertoli cell-only (SCO) phenotype, namely the MHC class II gene HLA-DRB1 (rs1136759, P = 1.32E-08, OR = 1.80) and an upstream locus of VRK1 (rs115054029, P = 4.24E-08, OR = 3.14), which encodes a protein kinase involved in the regulation of spermatogenesis. The SCO-associated rs1136759 allele (G) determines a serine in the position 13 of the HLA-DR beta 1 molecule located in the antigen-binding pocket. Overall, our data support the notion of unexplained SPGF as a complex trait influenced by common variation in the genome, with the SCO phenotype likely representing an immune-mediated condition. A GWAS in a large case-control cohort of European ancestry identifies two genomic regions, the MHC class II gene HLA-DRB1 and an upstream locus of VRK1, that are associated with the most severe phenotype of spermatogenic failure
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.
Location: Amazonia.
Taxon: Angiosperms (Magnoliids; Monocots; Eudicots).
Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.
Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.
Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis).
Time period: Tree-inventory plots established between 1934 and 2019.
Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.
Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.
Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.
Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.
Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
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