First-trimester genetic diagnosis in multiple pregnancy: Principles and potential pitfalls

Both the principles of first-trimester genetic diagnosis in multiple pregnancy and the special considerations required to avoid potential diagnostic pitfalls are presented. The experience consisted of 65 cases of twins and one case of quadruplets. Dichorionic twins were recognized by sonography in 54 cases. Transabdominal aspiration was generally preferred to trans-cervical for obtaining chorionic tissue, although in two cases both approaches were used. Diagnostic error following erroneous sampling was reported in 3 out of 54 sets of dichorionic twins (5.5 per cent). When like-sex dichorionic twins cannot be differentiated by cytogenetic or DNA polymorphism studies, amniocentesis should be recommended to confirm the reliability of the result on chorionic tissue.     

高职院校产学研结合模式及其发展对策

本文提出怎样理解产学研相结合的问题,并从产学研不同层面进行分析,提出以市场为目标、以制度为保证实现产学研有效结合的思路。     

Physical-chemical and ecotoxicological evaluation of water based drilling fluids used in Italian off-shore

In order to evaluate the effects on the marine ecosystem caused by an eventual discharge into sea of water based drilling fluids, as current legislation allows, chemical and ecotoxicological analyses were performed on the most common drilling muds and products used in Italian off-shore activities. The chemical analysis on drilling fluids involved the leaching test and the measurement of total content of heavy metals, whereas biodegradation tests were performed on the products used in mud's formulations. As for ecotoxicological evaluation, two marine organisms, the crustacean Artemia salina and the diatom Phaeodactylum tricornutum, were selected to determine the LC₅₀ and the EC₅₀ respectively.     

On-field investigation and process modelling of End-of-Life Vehicles treatment in the context of Italian craft-type Authorized Treatment Facilities

The present article analyses the current situation of End-of-Life-of-Vehicles (ELVs) management in Europe, with particular attention on Italian condition. Similarly to other European countries, metal recycling is the main activity of the whole system, but such situation is evolving due to the 2000/53/EC Directive, which sets out targets for Reuse, Recycling and Recovery of ELVs. Due to the relevance of the ELVs problem, in 2008 Italian Ministry of Environment subscribed a framework agreement with competent stakeholders as carmakers, dismantlers, shredders. The main result is an industrial plan to promote (amongst other objectives) technological progress for residual waste (Automotive Shredder Residue – ASR) treatment. According with Italian Trial 2006 analysis about ELVs, Reuse and Recycling rate is currently estimated to be about 81%.At the present time, dismantling plants constitute the first collection points for ELVs; for this reason, during 2009 an investigation has been done over a number of ten Authorized Treatment Facilities (ATFs) operating in Italy. The first step of the analysis was aimed to find out major practices and methods through observations of ATFs activities and interviews to operators. Furthermore, the depollution and dismantling treatments of about 70 different ELVs have been observed and timed in detail over a period of three months. The results included the identification of most relevant critical issues in ELVs treatment, such as distortions between scrapping activities and Directive’s regulation, and the assessment of the time and of the resources needed to perform each operation.In the second step of the survey, a process simulation model has been built on the basis of such data. The model was aimed to include the real variability and all the uncertainties that are typical of dismantling activities; it is intended as a tool for process layout planning and for its management. Some control parameters have been introduced; these are able to dynamically modify process path depending on ELVs queues and priorities. The model can also be used for the economic assessments of single operations or of the whole treatment activity.     

Finite population properties of individual predictors based on spatial patterns

In this study a conceptual framework for assessing the statistical properties of a non-stochastic spatial interpolator is developed through the use of design-based finite population inference tools. By considering the observed locations as the result of a probabilistic sampling design, we propose a standardized weighted predictor for spatial data starting from a deterministic interpolator that usually does not provide uncertainty measures. The information regarding the coordinates of the spatial locations is known at the population level and is directly used in constructing the weighting system. Our procedure captures the spatial pattern by means of the Euclidean distances between locations, which are fixed and do not require any further assessment after the sample has been drawn. The predictor for any individual value turns in a ratio of design-based random quantities. We illustrate the predictor design-based statistical properties, i.e. asymptotically p-unbiasedness and p-consistency, for simple random sampling without replacement. An application to a couple of environmental datasets is presented, for assessing predictor performances in correspondence of different population characteristics. A comparison with the equivalent non-spatial predictor is presented.     

Reference criteria for the identification of accident scenarios in the framework of land use planning

Land use planning (LUP) around industrial sites at risk of major accidents requires the application of sound approaches in the selection of credible accident scenarios. In fact, the ‘technical’ phase of LUP is based on the identification and assessment of relevant accident scenarios. An improper choice of scenarios may critically affect both the ‘technical’ phase of risk assessment and the following ‘policy’ phase concerning decision making on land-use restrictions and/or licensing. The present study introduces a procedure aimed at the systematic identification of reference accident scenarios to be used in the gathering of technical data on potential major accidents, which is a necessary step for LUP around Seveso sites. Possible accident scenarios are generated by an improved version of the MIMAH methodology (Methodology for the Identification of Major Accident Hazards). The accident scenarios are then assessed for LUP relevance considering severity, frequency and time scale criteria. The influence of prevention and mitigation barriers is also taken into account. Two applications are used to demonstrate the proposed procedure. In both case-studies, the proposed methodology proved successful in producing consistent sets of reference scenarios.