1,720,968 research outputs found
A closed-loop packaging network design model to foster infinitely reusable and recyclable containers in food industry
Full text linkThe current public and private policies pursuing environmental sustainability targets mandate incisive management of packaging waste, starting with those sectors that use virgin materials most. Food industries and food supply chains adopt huge volumes of plastic crates, cardboard boxes, and wooden boxes as transport packaging, thereby representing a hotspot and an urgent call for scholars and practitioners to address. Whilst wooden and cardboard boxes are disposable solutions, plastic containers can be employed as infinitely reusable and recyclable packages but require complex logistic systems to manage their life cycle. Optimization techniques can be exploited to aid the design and profitability of such complex packaging networks. This paper falls within the scarce literature on the design of pooling networks for reusable containers in the food industry. It proposes a strategic mixed-integer linear programming model to design a closed-loop system from the perspective of the packaging maker responsible for serving a food supply chain. The container's lifespan, i.e. the number of cycles a package can be reused before recycling, represents a crucial aspect to consider when modeling such networks. Incorporating lifespan constraints within the proposed closed-loop network design model is the main novel contribution we provide to the literature. This model is applied to a real-world instance of an Italian package pooler operating with a consortium of large-scale retailers for the distribution of fruits, vegetables, bakery, and meat products. A multi-scenario what-if analysis showcases how the optimal network evolves according to potential variations in the packaging demand, as well as in the container lifespan, demonstrating how to lead packaging makers to the profitability and the long-term sustainability of the closed-loop network
Phosphorylation-dependent degradation of MEF2C contributes to regulate G2/m transition
Full text linkThe Myocyte Enhancer Factor 2C (MEF2C) transcription factor plays a critical role in skeletal muscle differentiation, promoting muscle-specific gene transcription. Here we report that in proliferating cells MEF2C is degraded in mitosis by the Anaphase Promoting Complex/Cyclosome (APC/C) and that this downregulation is necessary for an efficient progression of the cell cycle. We show that this mechanism of degradation requires the presence on MEF2C of a D-box (R-X-X-L) and 2 phospho-motifs, pSer98 and pSer110. Both the D-box and pSer110 motifs are encoded by the ubiquitous alternate alpha 1 exon. These two domains mediate the interaction between MEF2C and CDC20, a co-activator of APC/C. We further report that in myoblasts, MEF2C regulates the expression of G2/M checkpoint genes (14-3-3 gamma, Gadd45b and p21) and the sub-cellular localization of CYCLIN B1. The importance of controlling MEF2C levels during the cell cycle is reinforced by the observation that modulation of its expression affects the proliferation rate of colon cancer cells. Our findings show that beside the well-established role as pro-myogenic transcription factor, MEF2C can also function as a regulator of cell proliferation
A Data Architecture to aid Life Cycle Assessment in closed-loop Reusable Plastic Container networks
Full text linkReturnable container networks have caught the eye of those companies that aim to reduce waste generation and environmental impact. The literature already includes studies on the environmental impact (i.e. Life Cycle Assessment, LCA) of these networks. However, the major part is based on secondary data, since the collection of primary data results complex and time-intensive. This paper proposes an object-relational database dedicated to the storage of data from closed-loop reusable plastic crates (RPC) networks for fruits and vegetables. The goal is supporting scholars and managers during the LCA through a user-friendly data architecture, while suggesting structured guidelines for the primary data collection. Each node of the RPC network is characterized by a similar set of entity types, such as machines, that allows to process the RPCs with respect to specific cycles. Each entity, process and cycle is therefore reflected in the database by objects that are connected with relations
Environmental impacts of reusable transport items: A case study of pallet pooling in a retailer supply chain
Full text linkManufacturing, storage, and transportation processes are typically facilitated by pallets, containers, and other reusable transport items (RTIs) designed to guarantee many cycles along a lifespan of several years. As a consequence, both supply and reverse transportation of RTIs need to be managed to avoid stockout along the supply chain and the unsustainable production of new tools from virgin materials. This paper focuses on the business of pallet management by analyzing the transport operations of a pallet pooling network serving a large-scale nationwide retailer. The pooler is responsible for supplying, collecting, and refurbishing pallets. The combination of the pooler's management strategies with different retailer network configurations results in different pooling scenarios, which are assessed and compared in this paper through a what-if analysis. The logistical and environmental impacts generated by the pallet distribution activities are quantified per each scenario through a tailored software incorporating Geographic Information System (GIS) and routing functionalities. Findings from this analysis suggest how to reduce vehicle distance traveled (vehicles-km) by 65% and pollutant emissions by 60% by combining network infrastructures and pooling management strategies-identifying an empirical best practice for managers of pallet businesses
The effect of speed variation on initial and sustaned forces during pushing and pulling activities: a preliminary study
No full textPush and pull activities characterize a significant part of manual material handling tasks in industry. Epidemiological studies show that pushing and pulling activities are associated with shoulder and low back pain. The International Standard 11228-2 describes the approach for risk assessment of push/pull activities, providing the maximum acceptable initial and sus-tained forces for pushing and pulling. The Standard defines maximum acceptable forces, re-quiring not to push/pull faster than a prescribed speed limit (0.1m/s for initial force and 0.3m/s for sustained force). Previous studies and current practice show that workers push carts faster.
The purpose of this study was to evaluate the relationships between speed variation and push forces for pushing tasks in industry. An industrial cart was pushed at different speed val-ues. Maximum initial and sustained push forces were measured. Results showed that increas-ing speed was highly correlated to increasing push forces. The findings have practical value for researchers, occupational physicians and ergonomics practitioners
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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