105 research outputs found

    A proposal for a green supply chain strategy

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    Purpose: The purpose of this paper is to establish a set of steps for helping companies to create a Green Supply Chain Strategy based on the reduction of their carbon footprint. The aim is to put forward a simple guideline that companies can follow and guide them in achieving their carbon emission targets, as well as obtaining attractive supply chain savings. Design/methodology/approach: Based on a literature review and benchmarking this paper proposes a methodology based on three pillars: 1) Corporate Carbon Strategy; 2) Carbon emission roadmap; and 3) Implementation and tracking. Analytic Hierarchy Process (AHP) techniques were used in order to create a green strategy and support the decision-making processes to select the most interesting alternatives for carbon emission reduction and supply chain savings. The supply chain of a metallurgical company is used to illustrate the case study where the proposed methodology is used. The criteria used for the carbon alternatives selection was based on three factors: 1) the supply chain cost of the alternative; 2) carbon emission impact in terms of CO2 tonnes; and 3) marketing effect. Findings: The paper identifies some specific steps for developing a Green Supply Chain Strategy. The case study developed, demonstrates the importance of following a proper methodology based on a set of steps, it also demonstrates that some alternatives focus on improving the supply chain, such as the facilities location, can also improve the key performance indicator related with carbon emission. Originality/value: The study provides guidance for manufacturing companies in implementing their Green Supply Chain Strategy.Peer ReviewedPostprint (author's final draft

    A methodology and a mathematical model for reducing greenhouse gas emissions through the suppply chain redesign

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    Virtually the entire scientific, political, business, and social community is aware of the importance of climate change. Countries adhering to the Kyoto Protocol have taken up the challenge of reducing carbon emission, implementing national policies that include the introduction of carbon emissions trading programs, voluntary programs, taxes on carbon emissions and energy efficiency standards. In this context, the business world must be able to generate a carbon reduction strategy to ensure long-term success, considering also that customers (and investors) are ever more interested in the well-being of the environment, and increasingly demand their suppliers to be eco-friendly. This thesis has addressed the problem of designing (or redesigning) the supply chain to reduce carbon emission in an economically viable and, as far as possible, optimal way. The thesis addresses the problem by designing a complete and formalized methodology, which also includes a mathematical model to determine the best decisions to take. The research begins, as usual, with a review of the basic terminology, standards and the scientific literature related to the topic. From the review of the literature, it has been concluded that, although there are authors who propose models related to the design of the supply chain including carbon reduction, there is a lack of formalized methodologies that can be applied to real cases . The methodology consists of 4 stages: 1) The creation of a corporate carbon strategy; 2) The alignment with strategic financial planning; 3) The development of a mathematical model; and 4) The implementation and tracking. In the first stage a six-step guide is developed to create a corporate carbon strategy. The steps are: 1) Determine the type of emission; 2) Boundaries definition; 3) Planning and performance information; 4) ldentify carbon reduction opportunities; 5) Determine carbon reduction goals; 6) Participating in programs and carbon markets . In the second stage, the corporate carbon strategy is evaluated from a financial point of view and integrated into the strategic planning. In the third stage, a Mixed lnteger Linear Programming (MILP) model is proposed to obtain a plan for the supply chain redesign, so that: 1) the carbon reduction targets are achieved; 2) the strategic financial plan is taken into account; 3) all the real possibilities are contemplated to redesign the supply chain; and 4) a solution is achieved to optimize the economic results of the company. The carbon reduction methodology , including the mathematical model, has been applied to three case studies that are useful for adjusting sorne elements and for its validation . The first case study corresponds to a company that operates in the Home and Personal Care sector in Brazil, where the system of taxes is more complex than in other countries and illustrates how the mathematical model can be adapted to any context. The second case study deals with a multinational company which operates in the Foods sector in Spain and requires a redesign of the supply chain to improve its product cost. Finally, the third case used a company in the U.S. to show the effect of the scope definition on the carbon strategy. In the three cases, the solution of the mathematical model maximizes the net profit, whilst the carbon reduction target is achieved. Therefore, the carbon reduction methodology is useful for achieving economic and environmental benefits, as well as providing benefits related to the improvement of the corporate image, strengthening of brands and avoiding possible carbon taxes risks. In conclusion, the carbon reduction methodology proposed in this thesis, was developed to support companies that want to generate a competitive advantage and a sustainable development. In addition, it was designed to be flexible enough to adapt to the needs of each business and facilitate its execution in the business world.Prácticamente toda la comunidad científica, política, comercial y social es consciente de la importancia del desafío medio ambiental relacionado con las emisiones de Gases de Efecto Invernadero (GEi). Los paises adheridos al Protocolo de Kioto han asumido el desafío de reducir los GEi, implementando políticas que incluyen programas de comercio de emisiones , programas voluntarios, impuestos sobre la emisión de GEi y normas sobre eficiencia energética. En este contexto, el mundo empresarial debe ser capaz de generar una estrategia de reducción de GEi para garantizar el éxito a largo plazo, considerando además que los clientes están cada vez más interesados en el bienestar del medio ambiente . Esta tesis ha abordado el problema de diseñar (o rediseñar) la cadena de suministro como vía para la reducción de GEi de una manera económicamente viable y, en la medida de lo posible, óptima. La tesis aborda la problemática diseñando una metodología completa y formalizada, que incluye también un modelo matemático para determinar las mejores decisiones a tomar. De la revisión de la literatura, se ha concluido que, si bien existen autores que proponen modelos relacionados con el diseño de la cadena de suministro que incluyen la reducción de GEi, no existen trabajos que propongan una metodología completa y suficientemente formalizada que puedan ser aplicados a la realidad. La metodología consta de 4 etapas que son: 1) La creación de una estrategia corporativa para la reducción de GEi; 2) La alineación con la planificación financiera estratégica; 3) El desarrollo de un modelo matemático; y 4) La implementación y seguimiento. En la primera etapa se desarrolla una guía de seis pasos para crear una estrategia corporativa para la reducción de GEi, los pasos son: 1) Determinar el tipo de emisión; 2) Definir el alcance; 3) Establecer las bases de la medición; 4) Identificar oportunidades de reducción de GEi; 5) Establecer los objetivos; 6) Planificar la participación en programas de reducción de GEi. En la segunda etapa, la estrategia corporativa antes propuesta, se evalúa desde un punto de vista financiero y se integra en la planificación estratégica. En la tercera etapa, se propone un modelo de Programación Lineal Entera Mixta para obtener un plan para et rediseño de ta cadena de suministro, de modo que: 1) se logren tos objetivos de reducción de GEi; 2) se tenga en cuenta el plan financiero estratégico; 3) se contemplen todas las posibilidades reales para rediseñar la cadena de suministro; y 4) se optimicen tos resultados económicos de la empresa. La metodología, incluyendo el programa matemático se ha probado en tres casos de estudio. El primer caso de estudio corresponde a una multinacional del sector de productos de higiene del hogar y cuidado personal que opera en Brasil, donde el modelo matemático fue adaptado para integrar beneficios fiscales. El segundo caso trata de una multinacional del sector alimentario basada en España que requiere un rediseño de la cadena de suministro para mejorar el coste de producir. Finalmente, en el tercer caso se utiliza una empresa del sector del metal basada en EE. UU., para ilustrar la importancia de la definición de límites y responsabilidades corporativas . En los tres casos de estudio, el modelo matemático maximiza el beneficio neto mientras alcanza el objetivo de reducción de GEi. Por lo tanto, la metodología es útil para conseguir beneficios económicos y medio ambientales, además de brindar beneficios relacionados con la mejora de la imagen corporativa, fortalecimiento de las marcas y el evitar posibles riesgos impositivos . En conclusión, la metodología propuesta fue desarrollada para que su implementación pueda generar en las empresas una ventaja competitiva y un crecimiento fundamentado en la sostenibilidad ambiental; asimismo, fue diseñada para que sea lo suficientemente flexible y pueda adaptarse a las necesidades de cada negoci

    Propuesta de un algoritmo genético para la programación diaria de los pedidos de una empresa del sector de la construcción

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    El objetivo del presente trabajo es proponer un algoritmo genético para determinar la programación integrada de la producción y de la distribución de un producto de carácter perecedero y no almacenable, el hormigón. La empresa en cuestión cuenta con diferentes plantas productivas desde las cuales distribuye los pedidos hasta cada obra, con la ayuda de una flota de vehículos. La programación de los pedidos se efectúa el día anterior a su distribución, siendo el objetivo cumplir con el nivel de servicio acordado con el cliente y minimizar su coste asociado. El problema es NP-hard. Los resultados obtenidos muestran que el algoritmo genético propuesto realiza la programación minimizando costes y respetando las condiciones de entrega pactadas con el cliente.Postprint (published version

    Conductas de control de peso en mujeres adolescentes dietantes y su relación con insatisfacción corporal y obsesión por la delgadez

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    ResumenIntroducciónLa obsesión por la delgadez y la insatisfacción corporal pueden llevar a las adolescentes a seguir dietas sin supervisión, lo que podría asociarse además a conductas riesgosas de control de peso, tales como ayuno, vómitos, uso de diuréticos y laxantes. El objetivo fue explorar conductas de control de peso en adolescentes dietantes y relacionarlas con insatisfacción corporal (IC) y obsesión por la delgadez (DT).Pacientes y MétodoEstudio transversal en 439 adolescentes de colegios públicos de Valparaíso diseñado para indagar conductas de control de peso riesgosas a través de escalas de IC y DT del Cuestionario de Trastornos Alimentarios (EDI-2), comparando dietantes y no dietantes.ResultadosEl 43% había realizado dieta sin supervisión médica. Las dietantes presentan valores superiores en DT e IC. El 29,6% de ellas presenta restricción alimentaria de riesgo moderado a alto, tomando como base el criterio de expertos, y se encuentran diferencias en la presencia y severidad de las conductas purgativas de control de peso entre los dos grupos estudiados.ConclusionesUn tercio de las adolescentes estudiadas hacen dietas sin supervisión profesional, presentan mayor IC y DT y conductas riesgosas de control de peso. Aquellas con sobrepeso y obesidad realizan dietas más restrictivas y conductas de control de peso más riesgosas.AbstractIntroductionObsession with thinness and body dissatisfaction can lead adolescents to follow unsupervised diets, which could result in risky weight control behaviors such as fasting, vomiting, use of diuretics and laxatives. The aim of the current study is to examine weight control behaviors in dieting adolescents and relate them to body dissatisfaction (BD) and obsession with thinness (OT).MethodsA cross-sectional study was conducted on 439 adolescents from Valparaiso public schools to investigate risky weight control behaviors due to BD and OT scales from the Eating Disorders Inventory-2 (EDI-2), comparing restrained eaters and non-restrained eaters.ResultsA total of 43% adolescents had followed a weight loss diet without medical supervision. The dieters had higher BD and OT values. Moderate to severe food restriction, based on expert judgment, was observed in 29.6%, and differences in the presence and severity of purging behaviors were found between the 2 groups.ConclusionsOne third of the adolescents studied followed diets without professional supervision and had higher BD and OT values, as well as risky weight control behaviors. Overweight and obese adolescents followed more restrictive diets and developed riskier weight control behaviors

    Response-Adapted Postinduction Strategy in Patients With Advanced-Stage Follicular Lymphoma: The FOLL12 Study

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    Purpose: We compared 2 years of rituximab maintenance (RM) with a response-adapted postinduction approach in patients with follicular lymphoma who responded to induction immunochemotherapy. Methods: We randomly assigned treatment-naïve, advanced-stage, high-tumor burden follicular lymphoma patients to receive standard RM or a response-adapted postinduction approach on the basis of metabolic response and molecular assessment of minimal residual disease (MRD). The experimental arm used three types of postinduction therapies: for complete metabolic response (CMR) and MRD-negative patients, observation; for CMR and MRD-positive (end of induction or follow-up) patients, four doses of rituximab (one per week, maximum three courses) until MRD-negative; and for non-CMR patients, one dose of ibritumomab tiuxetan followed by standard RM. The study was designed as noninferiority trial with progression-free survival (PFS) as the primary end point. Results: Overall, 807 patients were randomly assigned. After a median follow-up of 53 months (range 1-92 months), patients in the standard arm had a significantly better PFS than those in the experimental arm (3-year PFS 86% v 72%; P < .001). The better PFS of the standard vs experimental arm was confirmed in all the study subgroups except non-CMR patients (n = 65; P = .274). The 3-year overall survival was 98% (95% CI, 96 to 99) and 97% (95% CI, 95 to 99) in the reference and experimental arms, respectively (P = .238). Conclusion: A metabolic and molecular response-adapted therapy as assessed in the FOLL12 study was associated with significantly inferior PFS compared with 2-year RM. The better efficacy of standard RM was confirmed in the subgroup analysis and particularly for patients achieving both CMR and MRD-negative

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

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    The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

    Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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    We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file
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