532 research outputs found

    Economic–financial evaluation and multicriteria analysis of innovative public transport guided systems: an application to “Linea della Musica” in Rome

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    Trams and innovative public transport systems in historical city centres, are often not considered by public authorities, due to their strong visual impact, (e.g. in proximity of artistic-cultural places), and high project costs. The decision-makers guess that the high initial investment could not be compensated for in subsequent years. For this reason, it is very important to evaluate all the innovative solutions, not only economically, but considering all externalities, positive and negative, in a multi-criteria analysis taking into account public opinions and passengers’ behaviours essential for assessing revenues, and also return of image. On this basis, the results may be impressive: the positive economic impact may be highlighted, and they can have a result better than traditional systems. The subject of the analysis is the innovative system “Tramwave” of Ansaldo STS that combines an investment cost imperceptibly higher than the traditional tram, and a zero visual impact due to the absence of the overhead line due to the uptake of electrical energy from the ground. This system, applied to “Linea della Musica”, a planned tramway line in Rome, through a detailed financial balance of costs and revenues, shows a positive Net Present Value 30–40 years after the initial investment. The current crisis, both culturally and economically, can cause two types of reactions: an indiscriminate cutting of essential public services, or a positive crackdown, that puts ideas in motion, awakens the pride of the common good, and realizes innovations for saving money. The proposed analysis will try to encourage the second reaction

    Photonic band gaps analysis of Thue-Morse multilayers made of porous silicon

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    Dielectric aperiodic Thue-Morse structures up to 128 layers have been fabricated by using porous silicon technology. The photonic band gap properties of Thue-Morse multilayers have been theoretically investigated by means of the transfer matrix method and the integrated density of states. The theoretical approach has been compared and discussed with the reflectivity measurements at variable angles for both the transverse electric and transverse magnetic polarizations of light. The photonic band gap regions, wide 70 nm and 90 nm, included between 0 and 30°, have been observed for the sixth and seventh orders, respectively

    Playing with light in diatoms: microalgae with a natural photonic crystal structure

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    Complex micro- and nano-structured materials for photonic applications are designed and fabricated using top technologies. A completely different approach to engineering systems at the sub-micron-scale consists in recognizing the nanostructures and morphologies that nature has optimized during life’s history on earth. In fact, biological organisms could exhibit ordered geometries and complex photonic structures which often overcome the products of the best available fabrication technologies [1]. An example is given by diatoms, microalgae with a peculiar cell wall consisting of amorphous hydrated silica valves reciprocally interconnected in a structure called the frustule. Valve surfaces exhibit specie-specific patterns of regular arrays of chambers, called areolae, developed into the frustule depth. Areolae range in diameter from few hundreds of nanometers up to few microns, and can be circular, polygonal or elongate [2]. The formation of these patterns can be modeled by self-organised, genetically controlled processes. Despite of the high level of knowledge on the genesis and morphology of diatom frustules, their functions are not completely understood [2]. In this work, we show that the silica valves of marine diatoms, characterized by a photonic crystal-like structure, have surprising optical properties, being capable of filtering and focalizing light, as well as exhibiting optical sensing capabilities

    Survey on broiler pre-slaughter mortality in a commercial abattoir of central Italy

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    The pre-slaughter mortality was investigated on broilers, in the Mediterranean climate condition, considering the most significant risk factors as the journey length, waiting time, season and the space allowance in cages. At first, the pre-slaughter mortality was studied considering the totality of birds and then by examining in detail three broiler categories: large, medium and small size. The average dead on arrival (DOA) recorded on the totality of birds throughout the year was 0.38% and the values obtained in winter, spring, summer and autumn were 0.52, 0.48, 0.31 and 0.22%, respectively. The mortality rate observed during the year was 0.52, 0.47 and 0.31% for large, medium and small broilers, respectively. In all three groups, the maximum values of mortality were obtained in winter, whereas the minimum ones were recorded in autumn, spring and summer for large, medium, and small size birds, respectively. The increase of journey length could cause a higher mortality rate whereas the increase of the waiting time in the facilities at controlled environmental conditions did not seem to be a risk factor, but rather a mean to reduce the number of dead animals (all P < 0.05). It is concluded that the resistance to the hostile weather conditions, long journeys and extended waiting times was strongly related with the body weight of broilers; therefore, the planning of the slaughtering activity should consider this aspect, in order to avoid animal suffering and the economic loss

    Welfare indicators during broiler slaughtering

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    1. The aim of this study was to identify the most relevant welfare indicators for unloading, lairage, stunning, killing and post-mortem inspection in a poultry slaughter plant. Different indicators were unloading duration, lairage time, environmental variables in the lairage facilities, shackling time and electrical variables used in the water bath. 2. Lairage time did not correlate strongly with dead on arrival. Heat stress was limited by means of ventilation systems, correct cage placement and appropriate stocking density per crate. The acceptable shackling period was about 30 s. 3. The presence of a corneal reflex showed that an animal was alive, while spontaneous wing flapping, spontaneous eye blinking and response to a painful stimulus were regarded as indicators of stunning efficiency. 4. It was concluded that the presence of recent traumatic injuries during the post-mortem inspection could be a valid means to establish whether corrective measures concerning the handling, transport and loading procedures should be taken

    Effect of selected starter cultures on physical, chemical and microbiological characteristics and biogenic amine content in protected geographical indication Ciauscolo salami

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    The aim of the study was to evaluate the biogenic amine (BA) content of Ciauscolo salami made with and without the use of a selected started culture. Two batches of salami were made following the guidelines of the Protected Geographical Indications: with and without adding a commercial starter culture made of Lactobacillus plantarum and Staphylococcus xylosus. Six samples of salami per batch were collected at different ripening times (0, 15, 30, 45 and 60 days) for physical, chemical and microbiological analyses and for the determination of BA content. No differences were recorded for physical, chemical and microbiological analyses except for Staphylococcus spp. count at the time of casing (T0) and total volatile basic nitrogen (TVBN) from 30 days (T2) to the end of the ripening time (60 days, T4). After 60 days of ripening, the use of selected starter culture significantly affected the amount of putrescine (195.15 vs 164.43 mg/100 g in salami without and with starters, respectively), cadaverine (96.95 vs 104.40 mg/100 g in salami without and with starters, respectively), histamine (81.94 vs 69.89 mg/100 g in salami without and with starters, respectively), and spermine (36.88 vs 33.57 mg/100 g in salami without and with starters, respectively). Despite significantly higher values of TVBN, the use of selected starter culture determined no significant effects on the BA content of the products

    Porous silicon-based aptasensors: The next generation of label-free devices for health monitoring

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    Aptamers are artificial nucleic acid ligands identified and obtained from combinatorial libraries of synthetic nucleic acids through the in vitro process SELEX (systematic evolution of ligands by exponential enrichment). Aptamers are able to bind an ample range of non-nucleic acid targets with great specificity and affinity. Devices based on aptamers as bio-recognition elements open up a new generation of biosensors called aptasensors. This review focuses on some recent achievements in the design of advanced label-free optical aptasensors using porous silicon (PSi) as a transducer surface for the detection of pathogenic microorganisms and diagnostic molecules with high sensitivity, reliability and low limit of detection (LoD)

    Differences in chemical, physical and microbiological characteristics of Italian burrata cheeses made in artisanal and industrial plants of Apulia Region

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    The burrata cheese is a traditional product from Southern Italy, consisting of an envelope of pasta filata (stretched curd) filled with cream and pasta filata strips (usually leftovers from mozzarella production). Physical [water activity (aw), pH], chemical (moisture, NaCl content) and microbiological [total viable count (TVC), Listeria monocytogenes, Salmonella spp., Yersinia enterocolitica, Bacillus cereus, Escherichia coli, Enterobacteriaceae, coagulase-positive staphylococci] characteristics of burrata cheeses manufactured in artisanal and industrial plants were evaluated. The artisanal burrata showed lower aw values in the filling and the final product. The same was recorded in the filling for the moisture, probably due to differences between the types of cream used in the artisanal and the industrial cheesemaking. The pH value of the filling differed between the two groups but no difference was recorded in the final product. Microbiological differences were also recorded, with higher values for TVC and E. coli in artisanal than industrial burrata. All samples were negative for the other microbialdeterminations, with the exception of coagulase-positive staphylococci and Y. enterocolitica, which were detected in artisanal burrata. Differences in cheesemaking process were probably responsible for the strong variability of the physical and chemical data between the two cheeses; furthermore, differences in the hygienic features were also recorded. Even though artisanal products showed lower aw and pH values and higher NaCl concentration, the higher E. coli loads highlighted the need for a more accurate compliance with hygienic procedures along the artisanal cheesemaking process
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