5,584 research outputs found

    A roadmap for sustainability assessment in the food supply chain

    Get PDF
    Purpose: To develop a roadmap of sustainability practices and assessment mechanisms to advance in the sustainable supply chain (SSC) performance assessment in the food supply chain. The analysis is grounded on the contingency and stakeholder theories. Design/methodology/approach: The study follows a multiple case study approach analyzing the sustainability practices implementation and assessment across different supply chain stages in the food industry in Italy. The set of cases comprises 12 companies in the fresh fruit and vegetables (FFV), and seven companies in the “Balsamic Vinegar of Modena” (BVM) supply chains. Findings: The sustainability practices and assessment in each company in both supply chains according to their objectives are identified. Different stakeholder pressures for sustainability implementation and assessment are analyzed. The contingency factors that foster sustainability assessment are outlined as well. Finally, the study develops a roadmap with five levels of progress considering the groups of practices implemented and the type of assessment applied. Practical implications: The roadmap is a decision-making tool for planning and monitoring progress on SSC performance along five possible levels of progress. While identifying the assessment mechanisms implemented for different kind of sustainability practices, companies can develop a strategy according to their aims and capabilities and stakeholder's expectations. Originality/value: The novelties in this study are threefold. First, the roadmap with five levels of progress. Second, investigating two different food supply chains that allowed for a broader view regarding sustainability practices and assessment. Third, the adoption of stakeholder and contingency theories in SSC studies

    Modelo de masa incorporada en pinares mediterráneos: un caso de estudio en rodales de pino silvestre (Pinus sylvestris L.) y pino negral (Pinus pinister Ait.) en España

    Get PDF
    National Forest Inventories (NFI) are a basic tool for forestry planning at the National level. A new two-step system for predicting ingrowth compatible with NFI data is presented in order to improve long-term estimation of stand condition. In growth and yield models, an ingrowth submodel is a key feature for long-term estimation. An accurate projection of ingrowth is needed to avoid model projection bias and inaccuracy. A two-step approach was used, which consisted of (I) estimating the probability of ingrowth occurrence on a sample plot and (II) quantifying the ingrowth in terms of basal area. Logistic regression was used for step 1, while linear regression was used for step 2. A good performance of the joint ingrowth model for Scots pine (Pinus sylvestris L.) and Mediterranean Maritime pine (Pinus pinaster AiSsp mesogeensis) stands was observed. Logistic model include quadratic mean diameter as independent variables for both species while basal area is only included for Mediterranean Maritime. Quadratic mean diameter is the only independent variable in linear model for both species. The presented two-step modeling methodology for ingrowth is applicable to data from National Forest Inventories with concentric plots.Los Inventarios Forestales Nacionales (IFN) son un instrumento básico para la planificación forestal a nivel nacional. Con el objeto de predecir la masa incorporada, se presenta un nuevo sistema bietápico compatible con los datos del IFN para de esta forma mejorar las estimaciones a largo plazo. En los modelos de crecimiento y producción, un modelo de masa incorporada es clave para la proyección a largo plazo dado que se precisa una adecuada estimación de la masa incorporada para evitar sesgos e imprecisiones. Se utilizó un método bietápico basado en (I) estimar la probabilidad de presencia de masa incorporada en la parcela y (II) cuantificar la masa incorporada en área basimétrica. Para el paso 1 se utilizó la regresión logística mientras que para el paso 2 se utilizó regresión lineal. Se observó un buen comportamiento del modelo conjunto tanto para pino silvestre (Pinus sylvestris L.) como para pino negral (Pinus pinaster AiSsp mesogeensis). El modelo logístico incluye el diámetro medio cuadrático como variable independiente para ambas especies mientras que el área basimétrica solo es significativa en el caso del pino negral. En el modelo lineal, el diámetro medio cuadrático es significativo para las dos especies. El método bietápico presentado para estimar la masa incorporada es aplicable a los datos de Inventarios Forestales Nacionales basados en parcelas concéntricas

    Environmental effects on galaxy evolution. II: quantifying the tidal features in NIR-images of the cluster Abell 85

    Full text link
    This work is part of a series of papers devoted to investigate the evolution of cluster galaxies during their infall. In the present article we imaged in NIR a selected sample of galaxies through- out the massive cluster Abell 85 (z = 0.055). We obtained (JHK) photometry for 68 objects, reaching 1 mag/arcsec^2 deeper than 2MASS. We use these images to unveil asymmetries in the outskirts of a sample of bright galaxies and develop a new asymmetry index, alpha_An, which allows to quantify the degree of disruption by the relative area occupied by the tidal features on the plane of the sky. We measure the asymmetries for a subsample of 41 large area objects finding clear asymmetries in ten galaxies, most of them being in groups and pairs projected at different clustercentric distances, some of them located beyond R500 . Combining information on the Hi-gas content of blue galaxies and the distribution of sub-structures across Abell 85, with the present NIR asymmetry analysis, we obtain a very powerful tool to confirm that tidal mechanisms are indeed present and are currently affecting a fraction of galaxies in Abell 85. However, when comparing our deep NIR images with UV-blue images of two very disrupted (jellyfish) galaxies in this cluster, we discard the presence of tidal 1 interactions down to our detection limit. Our results suggest that ram-pressure stripping is at the origin of such spectacular disruptions. We conclude that across a complex cluster like Abell 85, environment mechanisms, both gravitational and hydrodynamical, are playing an active role in driving galaxy evolution.Comment: 30 pages, 13 figures, Accepted for Publication in A

    Cambios florísticos inducidos por los incendios en repoblaciones de Pinus sylvestris en el noroeste de España

    Get PDF
    The effects of wildfire on vegetation regeneration in the understory of stands dominated by Pinus sylvestris L. in north-west Spain were analysed. In order to study changes in the composition of this community, three study areas dominated by Pinus sylvestris L. and burned by a summer wildfire were selected. In each area three permanent plots of 25 × 1 m2 was established. The cover percentage of plant species present, and the cover of life forms and richness were analysed yearly from the first to the fourth year after fire. Total cover values generally increased throughout the study period. The species that appeared during the first years were those that would dominate in the mature stage, such as Erica australis L. and Pterospartum tridentatum (L.) Willk, both species being typical resprouters. Other species that appeared from the first year are typical seeders like Pinus sylvestris L. and Halimium alyssoides (Lam.) K. Koch. Floristic richness values showed higher values during the first year after fire than in the original situation, due to the fast recovery of the herbaceous species in the open spaces created by fire. After the first year changes in richness values were not significantLos efectos del fuego sobre la regeneración de las comunidades vegetales en plantaciones de Pinus sylvestris L. en el noroeste de España han sido analizados. Para analizar los cambios en la composición y estructura de este tipo de comunidades, se seleccionaron tres zonas de estudio en plantaciones de Pinus sylvestris L. y en ellas se seleccionaron áreas quemadas por un incendio de verano. En cada una de estas áreas se instalaron tres parcelas permanentes de 25 × 1 m2 donde se midió el porcentaje de cobertura por especies cada año desde un año hasta cuatro después del incendio. Los valores de cobertura total se incrementaron de forma gradual durante el periodo estudiado. Las especies que aparecen durante los primeros años son las que dominan en las etapas maduras, como Erica australis L. Pterospartum tridentatum (L.) Wilk. Otras especies que aparecen desde el primer año se regeneran obligatoriamente de semillas como Pinus sylvestris L. y Halimium alyssoides (Lam.) K. Koch. Los valores de riqueza florística encontrados en el primer año tras el incendio son mayores que los de la situación original debido a la rápida recuperación de las herbáceas en los espacios abiertos creados por el fuego. A partir del primer año los cambios en riqueza no fueron significativo

    Neutrino-induced nucleosynthesis of A>64 nuclei: The nu p-process

    Get PDF
    We present a new nucleosynthesis process, that we denote nu p-process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A >64. Making this process a possible candidate to explain the origin of the solar abundances of 92,94Mo and 96,98Ru. This process also offers a natural explanation for the large abundance of Sr seen in an hyper-metal-poor star.Comment: 5 pages, 3 figures, submitted to Physical Review Letter

    Cluster analysis for validated climatology stations using precipitation in Mexico

    Get PDF
    Annual average of daily precipitation was used to group climatological stations into clusters using the k-means procedure and principal component analysis with varimax rotation. After a careful selection of the stations deployed in Mexico since 1950, we selected 349 characterized by having 35 to 40 complete years of observations. The clustering of stations was performed three times: firstly according to the amount of precipitation; secondly according to their anomalies from the mean, resulting in their standard deviations grouping; and thirdly using the standardized anomalies, which resulted in a clustering according to the features of the trend and the structural changes of the series over the observing period. We identified two clusters that occupy northwestern and north-central Mexico; another at the center of the territory, between Sierra Madre Oriental and Sierra Madre Occidental; the following over the Sierra Madre Oriental; and a last one in the southeast of the territory, the southern coast of the Pacific Ocean and the Yucatán Peninsula, that overlaps with Sierra Madre Oriental group. Some stations of Yucatán Peninsula show similar characteristics to the northwestern cluster. The groupings were compared with the results of previous studies. The comparison indicates that regions are invariant in time and space and independent of the method of agregation and the stations sampled

    On the fraction of intermediate-mass close binaries that explode as type-Ia supernovae

    Full text link
    Type-Ia supernovae (SNe-Ia) are thought to result from a thermonuclear runaway in white dwarfs (WDs) that approach the Chandrasekhar limit, either through accretion from a companion or a merger with another WD. I compile observational estimates of the fraction eta of intermediate-mass stars that eventually explode as SNe-Ia, supplement them with several new estimates, and compare them self-consistently. The estimates are based on five different methods, each utilising some observable related to the SN-Ia rate, combined with assumptions regarding the IMF: the ratio of SN-Ia to core-collapse rates in star-forming galaxies; the SN-Ia rate per unit star-formation rate; the SN-Ia rate per unit stellar mass; the iron to stellar mass ratio in galaxy clusters; and the abundance ratios in galaxy clusters. The five methods indicate that a fraction in the range eta~2-40% of all stars with initial masses of 3-8 M_sun (the generally assumed SN-Ia progenitors) explode as SNe-Ia. A fraction of eta~15% is consistent with all five methods for a range of plausible IMFs. Considering also the binarity fraction among such stars, the mass ratio distribution, the separation distribution, and duplicity (every binary can produce only one SN-Ia explosion), this implies that nearly every intermediate mass close binary ends up as a SN-Ia, or possibly more SNe-Ia than progenitor systems. Theoretically expected fractions are generally one to two orders of magnitude lower. The problem could be solved: if all the observational estimates are in error; or with a ``middle-heavy'' IMF; or by some mechanism that strongly enhances the efficiency of binary evolution toward SN-Ia explosion; or by a non-binary origin for SNe-Ia.Comment: MNRAS, accepted versio

    Utilización de inmunoreacciones para la detección de Scrapie en Óbex de ovinos provenientes de la XII Región de Chile

    Get PDF
    Scrapie is an neurodegenerative and infectious disease that affects sheep and goats. The purpose of this study is to compare both tecniques, ELISA and IHC, to determine the application factibility giving the conditions of the laboratory in the country. To develop this assay, fourty obex samples were taken from sheep of the XII Region of Chile and were processed for both techniques ELISA and IHC. The results showed 100% of the samples negative for Scrapie, using both diagnostic methods. Based in obtained and previously reported results, ELISA technique can be recommended to use in massive screening, since yields reliable and rapid test results and IHC is a confirmatory technique. Both techniques are necessary in the creation of current epidemiological surveillance programs in Chile. ELISA and IHC are easily performed given the current laboratories conditions of the Chilean country.    El Scrapie es una enfermedad infecciosa neurodegenerativa que afecta a ovinos y caprinos. Dada la importancia que tiene esta enfermedad es que se desarrolló este estudio enmarcado en la comparación de la técnica de ELISA y la de inmunohistoquímica en el diagnóstico de Scrapie, para determinar la factibilidad de aplicarlas en las condiciones de laboratorio país. Para ello se procesaron 40 muestras de óbex de ovinos en duplicado, provenientes de la XII Región de Chile, las cuales fueron sometidas paralelamente a la técnica de ELISA e IHQ. Como resultados se obtuvo un 100% de muestras negativas a Scrapie, sometidas a ambos métodos diagnósticos. Con los valores informados previamente y los obtenidos en esta investigación, es posible recomendar el ELISA como una técnica utilizable en muestreos masivos, ya que aporta resultados confiables de manera más rápida. La IHQ corresponde a una técnica confirmatoria y que ambas, son necesarias en la creación de programas de vigilancia epidemiológica activa en Chile, siendo factibles de realizar en las actuales condiciones de laboratorio país.  
    corecore