64 research outputs found

    Towards more sustainable cities: tools and policies for urban goods movements

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    Although urban freight transportation is crucial to address societal demands, it also has a major negative impact on the environment, the economy, and society. Then, the growing interest in promoting more sustainable and liveable cities is pushing to point out more in depth the role of urban goods movements within the planning process, as well as city administrators to implement new sustainable city logistics actions/policies/measures. Therefore, after a brief overview, the study presents more advanced techniques (models and methodologies) to help in the assessment of planning scenario. This paper concentrates on the importance of urban freight transport and logistics. Then, technical and logistics actions are outlined, and future last-mile delivery challenges are discussed. The main objective is to support urban planners, on a strategic and tactical scale, in obtaining an overview of urban freight transport systems that point out the challenges for implementing sustainable city logistics scenarios. It is also of interest to technicians because they can identify the most suitable methodologies, as well as the features that they need for selecting and assessing ex ante the effects of city logistics measures. This work is useful for researchers in various sectors because it allows them to formalise and then to solve the problems for simulating the complex system of urban goods movements where there are different actors with own interests that are conflicting

    Mobility and land-use system in the sport mega-events. The case of the Cagliari stadium (Sardinia, Italy)

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    The evaluation of the mobility of the Sport infrastructures associated with Mega Events (SMEs), as football stadiums, and, in particular, the modal choices adopted by participants, are the focus of this study. Mobility, geographical aspects and urban planning that characterize a city hosting the SME are the main fields of investigation. In particular, in Italy there is a limited collaborative convergence among technical and scientific principles and the rules expressed by the Italian National Olympic Committee (CONI), to which an obsolete regulation for the accessibility of sports facilities refers. The progressive awareness of the communities on the fundamental role of sustainable mobility, energy efficiency, reduction of air pollution, also deriving from the impulse of the 2030 objectives, highlights how it is illusory to think of reaching them without gradual changes in the lifestyle of the communities themselves through political rules of urban development. Furthermore, the pandemic and the recent energy crisis highlighted the need to develop integrated systems - considering geographical, urban and regional planning, transport and mobility issues capable of innovating to improve planning activities and the quality of urban life

    The liquidity of dual-listed corporate bonds: empirical evidence from Italian markets

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    We compute some indicators (zero-trade, turnover ratio, Amihud price impact, and Roll bid-ask spread) to examine the liquidity conditions of corporate bonds traded on the main Italian retail bond markets from January 2010 to June 2013. In order to compare market liquidity for identical securities, our analysis focuses on fragmented bonds, i.e. bonds traded concurrently on two different venues: either DomesticMOT and EuroTLX, or ExtraMOT and EuroTLX. As for bonds traded on DomesticMOT and EuroTLX, the Amihud and the Roll statistics suggest EuroTLX being more liquid. Moreover, irrespective of the trading venue, on average bank bonds are less liquid than bonds issued by non-financial companies, especially from 2011 due to the impact of the sovereign debt crisis. With regard to bonds traded across ExtraMOT and EuroTLX, the latter is characterized by better liquidity conditions, with bank bonds being more liquid than non-financial ones. Furthermore, we find evidence of better liquidity figures for Italian bonds (nationality), structured bonds (complexity), and securities with greater minimum trading size (MTS). We also find that bonds’ features (issuers’ nationality and industry; bonds’ residual maturity, complexity, rating, etc…) affect liquidity differently depending upon the trading venue, thus supporting the view that market microstructure may play a relevant role. Finally, we investigate the effect of fragmentation by comparing the liquidity of dual-listed bank bonds fragmented across DomesticMOT and EuroTLX with otherwise similar bank bonds traded exclusively on DomesticMOT. Italian fragmented bank bonds turn out to be slightly more liquid than similar Italian bonds traded exclusively on DomesticMOT; whereas, the opposite holds for foreign bank bonds. However, overall there is not a clear-cut evidence on the effect of fragmentation on bond liquidity, probably because it is intertwined with bonds’ attributes, such as the issue size (in our sample, higher for the Italian bank bonds)

    The liquidity of dual-listed corporate bonds: empirical evidence from Italian markets

    Get PDF
    We compute some indicators (zero-trade, turnover ratio, Amihud price impact, and Roll bid-ask spread) to examine the liquidity conditions of corporate bonds traded on the main Italian retail bond markets from January 2010 to June 2013. In order to compare market liquidity for identical securities, our analysis focuses on fragmented bonds, i.e. bonds traded concurrently on two different venues: either DomesticMOT and EuroTLX, or ExtraMOT and EuroTLX. As for bonds traded on DomesticMOT and EuroTLX, the Amihud and the Roll statistics suggest EuroTLX being more liquid. Moreover, irrespective of the trading venue, on average bank bonds are less liquid than bonds issued by non-financial companies, especially from 2011 due to the impact of the sovereign debt crisis. With regard to bonds traded across ExtraMOT and EuroTLX, the latter is characterized by better liquidity conditions, with bank bonds being more liquid than non-financial ones. Furthermore, we find evidence of better liquidity figures for Italian bonds (nationality), structured bonds (complexity), and securities with greater minimum trading size (MTS). We also find that bonds’ features (issuers’ nationality and industry; bonds’ residual maturity, complexity, rating, etc…) affect liquidity differently depending upon the trading venue, thus supporting the view that market microstructure may play a relevant role. Finally, we investigate the effect of fragmentation by comparing the liquidity of dual-listed bank bonds fragmented across DomesticMOT and EuroTLX with otherwise similar bank bonds traded exclusively on DomesticMOT. Italian fragmented bank bonds turn out to be slightly more liquid than similar Italian bonds traded exclusively on DomesticMOT; whereas, the opposite holds for foreign bank bonds. However, overall there is not a clear-cut evidence on the effect of fragmentation on bond liquidity, probably because it is intertwined with bonds’ attributes, such as the issue size (in our sample, higher for the Italian bank bonds)

    A data mining approach to forecast late arrivals in a transhipment container terminal

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    One of the most important issues in Transhipment Container Terminal (TCT) management is to have fairly reliable and affordable predictions about vessel arrival. Terminal operators need to estimate the actual time of arrival in port in order to determine the daily demand for each work shift with greater accuracy. In this way, the resources required (human resources, equipment as well as spatial resources) can be allocated more efficiently. Despite contractual obligations to notify the Estimated Time of Arrival (ETA) 24 hours before arrival, ship operators often have to revise it due to unexpected events like weather conditions, delay in a previous port and so on. For planners the decision-making processes related to this topic can sometimes be so complex without the support of suitable methodological tools. Specific models should be adopted, in a daily planning scenario, to provide a useful support tool in TCTs. In this study, we discuss an exploratory analysis of the data affecting delays registered at a Mediterranean TCT. We present some preliminary results obtained using data mining techniques and propose a Classification and Regression Trees (CART) model to reduce the range of uncertainty of ship arrivals in port. This approach is compulsory to manage vast amounts of unstructured data involved in estimating of vessel arrivals

    a data mining approach to forecast late arrivals in a transhipment container terminal

    Get PDF
    One of the most important issues in Transhipment Container Terminal (TCT) management is to have fairly reliable and affordable predictions about vessel arrival. Terminal operators need to estimate the actual time of arrival in port in order to determine the daily demand for each work shift with greater accuracy. In this way, the resources required (human resources, equipment as well as spatial resources) can be allocated more efficiently. Despite contractual obligations to notify the Estimated Time of Arrival (ETA) 24 hours before arrival, ship operators often have to revise it due to unexpected events like weather conditions, delay in a previous port and so on. For planners the decision-making processes related to this topic can sometimes be so complex without the support of suitable methodological tools. Specific models should be adopted, in a daily planning scenario, to provide a useful support tool in TCTs. In this study, we discuss an exploratory analysis of the data affecting delays registered at a Mediterranean TCT. We present some preliminary results obtained using data mining techniques and propose a Classification and Regression Trees (CART) model to reduce the range of uncertainty of ship arrivals in port. This approach is compulsory to manage vast amounts of unstructured data involved in estimating of vessel arrivals

    Investigating the Role of the Human Element in Maritime Accidents using Semi-Supervised Hierarchical Methods

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    Navigation safety is a priority both at European and global level. Despite the important progress made over the years, sea accidents remain a major concern and much work is still needed to enhance maritime safety. Knowing the causes and precursors of past accidents is essential to identify the elements on which to intervene to improve safety and reduce the possibility of an accident to occur again. In this study, 1.079 sea accidents from the International Maritime Organization (IMO) database are analyzed using Semi-supervised Recursively Partitioned Mixture Models in an attempt to identify and categorize causal themes from accident data. Special attention is devoted to the human element, which is widely recognized as a primary or precursory cause in most accidents

    Prenatal exposure to different diets influences programming of glucose and insulin metabolism in dairy ewes.

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    ABSTRACT Nutrition in fetal and postnatal life can influence the development of several biological systems, with permanent effects in adult life. The aim of this work was to investigate in dairy sheep whether diets rich in starch or fiber during intrauterine life (75 d before lambing) and postnatal life (from weaning to first pregnancy; growth phase) program glucose and insulin metabolism in the female offspring during their first pregnancy. Starting from intrauterine life, 20 nulliparous Sarda ewes were exposed to 4 dietary regimens (n = 5 per group) based on different dietary carbohydrates during their intrauterine life and their subsequent growth phase: (1) the fiber (FI) diet during both intrauterine and growth life, (2) the starch (ST) diet during both intrauterine and growth life, (3) the FI diet in intrauterine life followed by the ST diet in the growth phase, and (4) the ST diet in intrauterine life followed by the FI diet in the growth phase. After the end of the growth phase, all growing ewes were fed the same diet and naturally mated. When ewes were pregnant, on average at 124 ± 2 d of gestation they were challenged with an intravenous glucose tolerance test, and peripheral concentrations of glucose and insulin were determined. Basal insulin concentrations were higher in ewes exposed to the ST diet (0.97 μg/L) than in ewes exposed to the FI diet (0.52 μg/L) in intrauterine life. After glucose infusion, glucose and insulin concentrations were not affected by intrauterine diet. Insulin resistance, determined by the homeostasis model assessment, was affected by the intrauterine × growth phases interaction. Insulin sensitivity, assessed by the quantitative insulin check index, was lower in ewes exposed to the ST diet than in those exposed to the FI diet in intrauterine life (ST = 0.28; FI = 0.30). Diet in growth life had no effect on glucose and insulin metabolism. In conclusion, starchy diets offered during intrauterine life but not during postnatal life increased basal insulin level and lowered insulin sensitivity during the first pregnancy. Nutritional strategies of metabolic programming should consider that exposure to starchy diets in late fetal life might favor the programming of dietary nutrient partitioning toward organs with high requirements, such as the gravid uterus or the mammary gland

    Polyphenolic Content and Antimicrobial Effects of Plant Extracts as Adjuncts for Craft Herbal Beer Stabilization

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    Extracts from locally grown aromatic plants can enhance the geographical characteristics and microbial stability of craft beers, which are often not pasteurized or filtered. Here, the chemical and antimicrobial properties of aqueous extracts from leaves of Myrtus communis L., Pistacia lentiscus L., Artemisia arborescens L., and floral wastes of Crocus sativus L., all cultivated in Sardinia (Italy), were assessed. P. lentiscus extract had the highest polyphenol content (111.20 mg GAE/g), followed by M. communis (56.80 mg GAE/g), C. sativus (32.80 mg GAE/g), and A. arborescens (8.80 mg GAE/g). Notably, only the M. communis extract demonstrated significant inhibitory activity against pathogenic and spoilage microorganisms, with minimum inhibitory concentrations of 0.18, 0.71, and 1.42 mg GAE/mL against Staphylococcus aureus, Lactiplantibacillus plantarum, and Lacticaseibacillus casei, respectively. Additionally, it reduced the growth of Levilactobacillus brevis and Fructilactobacillus lindneri at concentrations of 0.35 and 0.71 mg GAE/mL, respectively. Based on its significant antimicrobial activity, the M. communis extract was further characterized using high-resolution mass spectrometry, revealing high abundances of nonprenylated phloroglucinols, flavonoid derivatives (myricetin), and quinic acids. Lastly, adding M. communis extract (2.84 mg GAE/mL) to commercial beer effectively prevented the growth of L. brevis and F. lindneri, showing its potential to avoid beer's microbial spoilage
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