Planning a sustainable reverse logistics system: balancing costs with environmental and social concerns

The present work aims to support tactical and operational planning decisions of reverse logistics systems while considering economical, environmental and social objectives. In the literature, when addressing such systems economical aspects have been often used, while environmental concerns have been only recently emerging. The social component is the one less studied, and rarely the combination of the three concerns has been analyzed. This work address the three objectives and was motivated by the challenge of supporting decisions makers when managing a real case study of a recyclable waste collection system, where strategic decisions on the number and location of depots, vehicles and containers were taken beforehand. Tactical and operational decisions are studied involving the establishment of service areas for each depot and the definition and scheduling of collection routes for each vehicle. Such decisions should represent a compromise solution between the three objectives considered and support a sustainable reverse logistics plan. A multi-objective solution approach based on mixed-integer linear programming models is developed. Trade-offs between the objectives are discussed. Moreover the solutions obtained when each objective is tackled individually are compared between themselves and with the balanced solution.info:eu-repo/semantics/publishedVersio

Economic and environmental concerns in planning recyclable waste collection systems

This paper addresses the planning of recyclable waste collection systems while accounting for economic and environmental concerns. Service areas and vehicle routes are defined for multiple-depot logistics networks where different products have to be collected. The problem is modeled as a multi-product, multi-depot vehicle routing problem with two objective functions: distance and CO2 emissions minimization. A decomposition solution method is developed and applied to a real case-study. Six scenarios are studied regarding different service areas configuration and different objective functions. Savings up to 22% in distance and 27% in CO2 emissions are achieved, excelling economical and environmental goals.info:eu-repo/semantics/publishedVersio

From problem structuring to optimization: a multi-methodological framework to assist the planning of medical training

Medical training is an intricate and long process, which is compulsory to medical practice and often lasts up to twelve years for some specialties. Health stakeholders recognise that an adequate planning is crucial for health systems to deliver necessary care services. However, proper planning needs to account for complexity related with the setting of medical school vacancies and of residency programs, which are highly influenced by multiple stakeholders with diverse perspectives and views, as well as by the specificities of medical training. Aiming at building comprehensive models with a potential to assist health decision-makers, this article develops a multi-methodological framework to assist the planning of medical training under such a complex environment. It combines the structuring of the objectives and specificities of the medical training problem with a Soft Systems Methodology through the CATWOE (Customer, Actor, Transformation, Weltanschauung, Owner, Environment) approach, and the formulation of a Mixed Integer Linear Programming model that considers all relevant aspects. Considering the specificities of countries based on a National Health Service structure, a multi-objective planning model emerges, informing on how many vacancies should be opened/closed per year in medical schools and in each specialty. This model aims at (i) minimizing imbalances between medical demand and supply; (ii) minimizing costs; and (iii) maximizing equity across medical specialties. A case study in Portugal is explored so as to illustrate the applicability of the proposed multi-methodology, showing the relevance of proper structuring for planning models having the potential to inform health decision-makers and planners in practice.info:eu-repo/semantics/acceptedVersio

Promoção de uma oferta equitativa no setor dos cuidados continuados integrados: desenvolvimento de uma abordagem multi-período e multiobjetivo para apoio ao planeamento da oferta de cuidados

Este estudo propõe um modelo de programação matemática multi‑objetivo e multi‑período para apoiar as decisões de planeamento no setor dos cuida‑ dos continuados integrados (CCI). O modelo proposto permite apoiar o pla‑ neamento da oferta de CCI em regime de internamento, tanto em termos de seleção das melhores localizações para esses serviços, como também da capa‑ cidade a instalar, e isto com o propósito de construir uma rede de cuidados mais equitativa. Serão, assim, considerados três objetivos de equidade – equi‑ dade de acesso, equidade geográfica e equidade socioeconómica. Serão tam‑ bém contabilizados os custos, mas na forma de restrições do modelo. A funçãoobjetivo do modelo incorpora estes múltiplos objetivos de equidade através da atribuição de pesos que são obtidos com recurso à metodologia Measuring Attractiveness by a Category‑Based Evaluation TecHnique (MACBETH). A uti‑ lidade do modelo é ilustrada através da sua aplicação a um caso de estudo na região da Grande Lisboa em Portugal.info:eu-repo/semantics/publishedVersio

The boomerang returns? Accounting for the impact of uncertainties on the dynamics of remanufacturing systems

Recent years have witnessed companies abandon traditional open-loop supply chain structures in favour of closed-loop variants, in a bid to mitigate environmental impacts and exploit economic opportunities. Central to the closed-loop paradigm is remanufacturing: the restoration of used products to useful life. While this operational model has huge potential to extend product life-cycles, the collection and recovery processes diminish the effectiveness of existing control mechanisms for open-loop systems. We systematically review the literature in the field of closed-loop supply chain dynamics, which explores the time-varying interactions of material and information flows in the different elements of remanufacturing supply chains. We supplement this with further reviews of what we call the three ‘pillars’ of such systems, i.e. forecasting, collection, and inventory and production control. This provides us with an interdisciplinary lens to investigate how a ‘boomerang’ effect (i.e. sale, consumption, and return processes) impacts on the behaviour of the closed-loop system and to understand how it can be controlled. To facilitate this, we contrast closed-loop supply chain dynamics research to the well-developed research in each pillar; explore how different disciplines have accommodated the supply, process, demand, and control uncertainties; and provide insights for future research on the dynamics of remanufacturing systems

Melanoma do intestino delgado: primário ou metastático? um caso clínico

Malignant melanoma often originated from melanocytes can occur wherever these cells are present. Most common locations are the skin, retina, anus and under the nail. Although rare, primary gastrointestinal tract melanoma has been reported, mostly from the oesophagus and anorectal region. In the small bowel represents 5% of primary neoplasms. We report a case of a 70 year old man, who presented with abdominal pain, weigh loss and anaemia. Based on the findings of CT, endoscopy and entheroscopy a preoperative diagnosis of a small bowel tumour was established. Was submitted to a multiple segmental enterectomy, the histopathological examination revealed a malignant melanoma. A thorough postoperative investigation did not reveal a primary lesion in the skin, oculus or any other location. Brain and pulmonary metastasis where diagnosed afterwards and he died three months after surgery. In a patient without any obvious primary tumour, with a gastrointestinal melanoma and without extraintestinal lesions we should rule out primary gastrointestinal melanoma. Keywords: Malignant melanoma, small bowel, gastrointestinal tract. O melanoma tem geralmente a sua origem em células da linha melanocítica, podendo ocorrer em todos os locais onde estas células estão presentes. Localiza-se mais frequentemente na pele, retina, ânus, leito ungueal e plexos coroideus. Embora muito raro, foi documentado melanoma primitivo do tracto gastrointestinal, sobretudo no esófago e região ano-rectal. No intestino delgado representa cerca de 5% das neoplasias primárias. Expõe-se o caso de um homem de 70 anos, que se apresentou com dor abdominal, emagrecimento e anemia. Com base na TAC, endoscopia e enteroscopia por cápsula estabeleceu-se o diagnóstico clínico pré-operatório de neoformação do intestino delgado. Foi submetido a enterectomia segmentar múltipla, o exame anatomo-patológico da peça excisada revelou tratar-se de melanoma. Perante este diagnóstico, o doente foi exaustivamente estudado, no sentido de excluir lesões prévias, ou não, na pele ou em outras localizações que justificassem a hipótese de metastização de melanoma no tracto gastrointestinal mas nada foi encontrado. Posteriormente foram-lhe diagnosticadas duas lesões expansivas cerebrais e múltiplas lesões pulmonares, vindo a falecer três meses após a cirurgia. Num doente sem tumor primário óbvio e com melanoma gastrointestinal, sem evidência de lesões extra-intestinais, coloca-se a hipótese diagnóstica de melanoma primário do tracto gastrointestinal. Palavras-chave: Melanoma, intestino delgado, tracto gastro-intestinal.

Plasmodium vivax circumsporozoite genotypes: a limited variation or new subspecies with major biological consequences?

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium vivax </it>circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the <it>P. vivax </it>genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion.</p> <p>Methods</p> <p>The phylogenetic analyses were accomplished starting from the amplification of conserved domains of <it>18 SSU RNAr </it>and <it>Cyt B</it>. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two <it>P. vivax CS </it>genotypes: VK210 and <it>P. vivax</it>-like.</p> <p>Results</p> <p>These analyses of the two markers demonstrate high similarity among the <it>P. vivax CS </it>genotypes and surprisingly showed diversity equal to zero between VK210 and <it>P. vivax</it>-like, positioning these <it>CS </it>genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the <it>P. vivax </it>CSP was found as compared to the immune response to the R- and V- repetitive regions (<it>p </it>= 0.0005, Fisher's Exact test). This difference was more pronounced when the <it>P. vivax</it>-like variant was present in the infection (<it>p </it>= 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all <it>P. vivax CS </it>genotypes in comparison to the same frequency for DBP.</p> <p>Conclusions</p> <p>This results target that the differences among the <it>P. vivax CS </it>variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.</p

Vasopressors and Inotropes in the Treatment of Human Septic Shock: Effect on Innate Immunity?

Catecholamines have been suggested to modulate innate immune responses in experimental settings. The significance hereof in the treatment of human septic shock is unknown. We therefore sought if and how vasopressor/inotropic doses relate to pro-inflammatory mediators during treatment of septic shock. We prospectively studied 20 consecutive septic shock patients. For 3 days after admission, hemodynamic variables, lactate and plasma levels of interleukins (IL)-6 and 8, tumor necrosis factor (TNF)-α, and elastase-α1-antitrypsin were measured six hourly. Doses of vasoactive drugs were recorded. Of the 20 patients, nine died in the intensive care unit. Dobutamine doses were positively associated and related to TNF-α plasma levels, independently of disease severity, hemodynamics, and outcome, in multivariable models. Dopamine doses were positively associated with IL-6, and norepinephrine was inversely associated with IL-8 and TNF-α levels. Our observations suggest that catecholamines used in the treatment of human septic shock differ in their potential modulation of the innate immune response to sepsis in vivo. Dobutamine treatment may contribute to circulating TNF-α and dopamine to IL-6, independently of activated neutrophils. Conversely, norepinephrine may lack pro-inflammatory actions