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排序方式: 共有352条查询结果,搜索用时 31 毫秒
1.
Maria Grazia Basanisi Gianfranco La Bella Gaia Nobili Rosa Coppola Annita Maria Damato Maria Assunta Cafiero Giovanna La Salandra 《International Journal of Food Science & Technology》2020,55(3):1145-1150
The authenticity and traceability of meat products are issues of primary importance to ensure food safety. Unfortunately, food adulteration (e.g. the addition of inexpensive cuts to minced meat products) and mislabelling (e.g. the inclusion of meat from species other than those declared) happens frequently worldwide. The aim of this study was to apply a droplet digital PCR assay for the detection and quantification (copies μL−1) of the beef, pork, horse, sheep, chicken and turkey in meat products. The analysis conducted on commercial meat showed the presence of traces of DNA from other animal species than those declared. We show that the method is highly sensitive, specific and accurate (accuracy = 100%). This method could be adopted by competent food safety authorities to verify compliance with the labelling of meat products and to ensure quality and safety throughout the meat supply chain, from primary production to consumption. 相似文献
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We consider the problem of generating a large state-space in a distributed fashion. Unlike previously proposed solutions that partition the set of reachable states according to a hashing function provided by the user, we explore heuristic methods that completely automate the process. The first step is an initial random walk through the state space to initialize a search tree, duplicated in each processor. Then, the reachability graph is built in a distributed way, using the search tree to assign each newly found state to classes assigned to the available processors. Furthermore, we explore two remapping criteria that attempt to balance memory usage or future workload, respectively. We show how the cost of computing the global snapshot required for remapping will scale up for system sizes in the foreseeable future. An extensive set of results is presented to support our conclusions that remapping is extremely beneficial. 相似文献
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Marcella Bonchio Mauro Carraro Martino Gardan Gianfranco Scorrano Enrico Drioli Enrica Fontananova 《Topics in Catalysis》2006,40(1-4):133-140
The incorporation of decatungstate in polymeric membranes provides new heterogeneous photocatalysts for the oxidation of organic
substrates under oxygen atmosphere at 25 °C. Photocatalytic membranes have been prepared yielding polymeric films with a high
thermal, chemical and mechanical stability (PVDF, PDMS, Hyflon). Surface spectroscopy techniques including transmittance and
reflectance UV-Vis and FT-IR have been used to assess the photocatalyst integrity within the polymeric support. Catalyst screening
has been performed under both homogeneous and heterogeneous photooxygenation conditions. The photocatalyst activity has been
evaluated in terms of the substrate conversion, turnover numbers, and recycling experiments. A membrane induced selectivity
behavior has been evidenced by comparison with homogeneous oxidations. 相似文献
6.
Gianfranco Totani Ferdinando Totani Daniele Celli Davide Pasquali Marcello Di Risio 《Journal of Failure Analysis and Prevention》2017,17(1):86-92
This paper describes the results of site investigations, monitoring, stability analyses, and soil-pipe interaction modeling of a built-up slope located near Pineto (Abruzzo Province, Central Italy), where a gas pipeline exploded on March 6th, 2015, due to heavy rains inducing slope movements. The slope is formed by OC clay, covered with an upper 10- to 14-m-thick clayey-sandy silt colluvial layer. The explosion in the upper portion of the slope caused extensive damage to existing buildings and threatened human lives. Soon after the event, a site investigation and monitoring program was carried out. A detailed topographic survey and hydrological data were analyzed in order to characterize possible critical rainfall events. The stability of the slope was analyzed both in pre- and in post-explosion conditions. The profiles of the DMT horizontal stress index K D helped to identify multiple slip surfaces. Then, the results of the site investigation and stability analyses were used to implement a simplified finite element model aimed to describe the soil-pipeline interaction, taking into account the role of the observed wrinkle in the pipeline. The numerical simulations reveal the crucial role played by the slope movements, and by the wrinkle as well, in inducing the collapse of the pipe. 相似文献
7.
In 1950 Markowitz first formalized the portfolio optimization problem in terms of mean return and variance. Since then, the
mean-variance model has played a crucial role in single-period portfolio optimization theory and practice. In this paper we
study the optimal portfolio selection problem in a multi-period framework, by considering fixed and proportional transaction
costs and evaluating how much they affect a re-investment strategy. Specifically, we modify the single-period portfolio optimization
model, based on the Conditional Value at Risk (CVaR) as measure of risk, to introduce portfolio rebalancing. The aim is to
provide investors and financial institutions with an effective tool to better exploit new information made available by the
market. We then suggest a procedure to use the proposed optimization model in a multi-period framework. Extensive computational
results based on different historical data sets from German Stock Exchange Market (XETRA) are presented. 相似文献
8.
The determinization of a nondeterministic finite automaton (FA) is the process of generating a deterministic FA (DFA) equivalent to (sharing the same regular language of) . The minimization of is the process of generating the minimal DFA equivalent to . Classical algorithms for determinization and minimization are available in the literature for several decades. However, they operate monolithically, assuming that the FA to be either determinized or minimized is given once and for all. By contrast, we consider determinization and minimization in a dynamic context, where augments over time: after each augmentation, determinization and minimization of into is required. Using classical monolithic algorithms to solve this problem is bound to poor performance. An algorithm for incremental determinization and minimization of acyclic finite automata, called IDMA, is proposed. Despite being conceived within the narrow domain of model‐based diagnosis and monitoring of active systems, the algorithm is general‐purpose in nature. Experimental evidence indicates that IDMA is far more efficient than classical algorithms in solving incremental determinization and minimization problems. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
A software environment, called EDEN, that prototypes a recent approach to model-based diagnosis of discrete-event systems, is presented. The environment integrates a specification language, called SMILE, a model base, and a diagnostic engine. SMILE enables the user to create libraries of models and systems, which are permanently stored in the model base, wherein both final and intermediate results of the diagnostic sessions are hosted as well. Given the observation of a physical system gathered during its reaction to an external event, the diagnostic engine performs the a posteriori reconstruction of all the possible evolutions of the system over time and, then, draws candidate diagnoses out of them. The diagnostic method is described using a simplified example within the domain of power transmission networks. Strong points of the method include compositional modeling, support for model update, ability to focus on any sub-system, amenability to parallel execution, management of multiple faults, and broad notions of system and observation. 相似文献
10.
Gianfranco Bianco 《机械工人(冷加工)》2006,(11):45-46
一直以来,齿轮热处理后的精加工一般采用磨削或珩磨这两项工艺,但剃齿加工工艺仍有现实意义。首先,剃齿总费用仅是磨削总费用的一部分;其次,剃齿加工所用循环时间要短得多,这就意味着剃齿加工投入的资金和必需的机床要少很多。另外,还要考虑到齿轮加工不可能都采用磨削加工,有些精度不高的齿轮不需要磨削加工,比如带台肩的齿轮,汽车的倒挡齿轮与一、二挡齿轮,所有农业机械的齿轮以及低速的传动齿轮。 相似文献