A predictive model for the home outdoor exposure to nitrogen dioxide

The aim of this study is to find and test a predictive model that could be suitable to estimate the outdoor NO(2) concentrations at individual level, by integrating ecological measurements recorded by local monitoring stations with individual information collected by a questionnaire. For this purpose, the data from the Italian centres of the European Community Respiratory Health Survey II (ECRHS II) has been used. Outdoor NO(2) concentrations were measured using NO(2) passive sampling tubes (PS-NO(2)), exposed outdoor for 14 days, between January 2001 and January 2003. Simultaneously, average NO(2) concentrations were collected from all the monitoring stations of the three centres (MS-NO(2)). Individual measurements carried out with passive samplers were compared with the corresponding NO(2) 2-week concentrations obtained as the average of all local (background and traffic) monitoring stations (MS-NO(2)). A multiple linear regression model was fitted to the data using the 2-week PS-NO(2) concentrations as the response variable and questionnaire information and MS-NO(2) concentrations as predictors. The model minimizing the root mean square error (RMSE), obtained from a ten-fold cross validation, was selected. The model with the best predictive ability included centre, season of the survey, MS-NO(2) concentrations, type and age of building, residential area and reported intensity of heavy-duty traffic and explained the 68.9% of the variance. The non-parametric correlation between PS-NO(2) and the concentrations estimated by the model is 0.81 (95% CI: 0.77-0.85). This study shows that over short periods (2 weeks) a good prediction of home outdoor exposure to NO(2) can be achieved by simply combining routinely collected ecological data with dwelling characteristics and self-reported intensity of heavy traffic. Further studies are needed to extend this prediction to long-term exposure.     

连铸板坯鼓肚变形与宏观偏析的有限元分析

鼓肚变形及因变形引起的中心线偏析是影响板坯质量的重要因素.法国冶金部和一些企业组织了优化钢铁生产的项目,采用数值方法研究和优化连铸工艺.介绍了巴黎高等矿业学校在连铸过程数值仿真方面的研究成果.     

Fixed mesh front‐tracking methodology for finite element simulations

A direct front‐tracking method using an Eulerian–Lagrangian formulation is developed in two space dimensions. The front‐tracking method is general in that it can track any type of interface once its local velocity is specified or has been determined by calculation. The method uses marker points to describe the interface position and tracks the interface evolution on a fixed finite‐element mesh, including growth, contraction, splitting and merging. Interfacial conditions are applied directly at the interface position. The method is applied to three scenarios that involve different interface conditions and are based on energy and mass diffusion. The three calculations are for the dendritic solidification of a pure substance, the cellular growth of an alloy, and the Ostwald ripening of silica particles in silicon. Numerical results show that very complicated interface morphologies and topological changes can be simulated properly and efficiently. Copyright © 2004 John Wiley & Sons, Ltd.     

Visual Analysis of Trajectories in Multi‐Dimensional State Spaces

Multi‐dimensional data originate from many different sources and are relevant for many applications. One specific sub‐type of such data is continuous trajectory data in multi‐dimensional state spaces of complex systems. We adapt the concept of spatially continuous scatterplots and spatially continuous parallel coordinate plots to such trajectory data, leading to continuous‐time scatterplots and continuous‐time parallel coordinates. Together with a temporal heat map representation, we design coordinated views for visual analysis and interactive exploration. We demonstrate the usefulness of our visualization approach for three case studies that cover examples of complex dynamic systems: cyber‐physical systems consisting of heterogeneous sensors and actuators networks (the collection of time‐dependent sensor network data of an exemplary smart home environment), the dynamics of robot arm movement and motion characteristics of humanoids.     

金属标准物质中杂质的辉光放电质谱法溯源分析

标准物质定值分析的溯源性要求比常规分析高很多。在常规分析中,有证标准物质（CRM）可用于校准以及建立可溯源性。尽管与标准物质生产和认定相关的ISO导则并没有十分明确地提到校准,但众多标准物质生产者在定值分析时却不接受基准标准物质用于校准。这些要求制约了标准物质定值方法的使用,因为这些方法可以采用已知高纯度的标准物质、化学计量法及已知高纯度标准物质的混合物进行校准。有效的固体取样技术,例如通常使用的块状标准物质进行校准的辉光放电质谱法（GD MS）或火花源发射光谱法（spark OES）,似乎不太适合定值分析。尤其是固体样品中痕量元素分析测定的有力工具辉光放电质谱法,除金属杂质外,使用特定气体混合物,这种方法也可以分析相关的非金属杂质如硫和磷。我们开发了一种可以使用已知高纯度的标准物质混合物和化学计量法的校准方法,这种校准方法同样可用于辉光放电质谱法。与溶液中基体匹配技术类似,此校准方法基于掺杂的粉末压片。本文还结合铜和钢标准物质的定值分析结果进行了陈述。     

Balloon dilatation in acute myocardial infarct in routine clinical practice: results of the register of the Working Society of Leading Cardiologic Hospital Physicians in 4,625 patients

Balloon angioplasty as the treatment of first choice in the setting of an acute myocardial infarction (AMI) is gaining widespread acceptance because of favourable results from specialised centres concerning high patency rates and low mortality. This study reports the results of angioplasty for AMI at large community hospitals during 1992-1995. 4625 procedures were performed at 68 centres of the Arbeitsgemeinschaft Leitender Kardiologischer Krankenhaus?rzte (ALKK). The age of the patients was 60.8 +/- 11.3 years, with 75.1% men. The infarct related artery was the left anterior descendent in 43%, the right coronary artery in 37%, the circumflex artery in 16%, a bypass graft in 2.3% and the left main stem in 1.4% of patients. The success rate (residual stenosis < 50%) of the intervention was 86%. There was a wide range of procedures per centre, with a median of 40 AMI angioplasties per year and centre. The amount of angioplasties for AMI in relation to all angioplasties performed during this period rose from 5.2% in 1992 to 5.9% in 1995 (p = 0.01). Local complications at the puncture site occurred in 3.2%, with the need for a surgical intervention in 1.1% of patients. In 273 (5.9%) of the patients a second angioplasty was performed during the hospital stay. Aortocoronary bypass surgery was performed in 3% of the patients. Hospital mortality was 9.5% (438/4625 patients). The mortality rate remained constant during the years investigated (1992: 10.6%; 1993: 8.6%; 1994: 9.7%; 1995: 9.8%; p = ns). Higher mortality was observed in older patients, patients with multiple vessel disease, the left anterior descending artery or a bypass graft as infarct related artery as well as in patients with failed reperfusion (residual stenoses > 50%). Hospitals with a case load of more than 40 angioplasties for AMI per year showed a lower mortality as compared to the others. In clinical practice at large community hospitals results of angioplasty for AMI concerning mortality, complications and technical success rate are comparable to those of highly specialised centres. The absolute numbers of angioplasties for AMI increased constantly over the years.     

Uncertainty in Quantitative Electron Probe Microanalysis

Quantitative electron probe analysis is based on models based on the physics or x-ray generation, empirically adjusted to the analyses of specimens of known composition. Their accuracy can be estimated by applying them to a set of specimens of presumably well-known composition.     

Synthesis of Aminopyridazines from Aminocyclopropenylium Salts and Diazomethyl Compounds [1]

Amino-substituted cyclopropenylium salts ( 11a,b ) react with diazomethyl compounds ( 12a-i ) in dichloromethane or acetonitrile in the presence of a base (ethyldiisopropylamine, 1,5-diazabicyclo[4.3.0] non-5-ene) to form 4-aminopyridazines ( 13a-i ) specifically. The reaction is interpreted in terms of an initial electrophilic diazoalkane substitution to give diazomethylcyclopropenes ( 11 + 12 → 14 ) which undergo a [1.5]-cyclisation to form the betaines 16 which, in turn, isomerise with opening of the bridging bond to give the aminopyridazines 13 . In a similar manner, the tris[amino] cyclopropenylium salts 8a,b and 10a-c are converted to the 3,4,5-tris[amino]-pyridazines ( 21a-k ) by treatment with diazomethyl compounds ( 12a, c-f ).     

Die Bestimmung der Rohfaser in Kakao und Kakaoerzeugnissen

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