Epidemiological investigation on chronic copper toxicity to children exposed via the public drinking water supply

Copper in drinking water has been associated with Non-Indian Childhood Cirrhosis (NICC), a form of early childhood liver cirrhosis. This epidemiological study examines the exposition of infants to increased copper concentrations through drinking water from public water supplies in Berlin, Germany, and if this dietary copper intake can cause liver damage in early childhood. In total, water samples from 2944 households with infants were tested for copper. Mean copper concentrations in the two different types of collected composite samples were 0.44 and 0.56 mg/l, respectively. Families having a copper concentration at or above 0.8 mg/l in one or both of the composite samples (29.9% of all sampled households) and a defined minimum ingestion of tap water of their infant were recommended to undergo a paediatric examination. Nearly every of the 541 recommended infants were examined by a local paediatrician and of these 183 received a blood serum analysis, too. None of the infants had clear signs of a liver disease although a few serum parameters lay outside the accompanying reference range and abdominal ultrasound imaging gave slightly unusual results in five cases. Additionally, no signs of a negative health effect could be found in the statistical analysis of the serum parameters GOT, GPT, GGT, total bilirubin, serum copper, or ceruloplasmin in relation to estimated daily and total copper intakes of the infants from tap water. No dose relation of serum parameters and estimated copper intakes could be established. From the results of the study, no confirmed indication of a liver malfunction in infants whose food had been prepared using tap water with an elevated copper concentration could be found and, therefore, no indication of a hazard due to copper pipes connected to public water supplies could be detected.     

Theoretical calculations and performance results of a PZT thin film actuator

High piezoelectric coupling coefficients of PZT-based material systems can be employed for actuator functions in micro-electro-mechanical systems (MEMS) offering displacements and forces which outperform standard solutions. This paper presents simulation, fabrication, and development results of a stress-compensated, PZT-coated cantilever concept in which a silicon bulk micromachining process is used in combination with a chemical solution deposition (CSD) technique. Due to an analytical approach and a finite element method (FEM) simulation for a tip displacement of 10 /spl mu/m, the actuator was designed with a cantilever length of 300 /spl mu/m to 1000 /spl mu/m. Special attention was given to the Zr/Ti ratio of the PZT thin films to obtain a high piezoelectric coefficient. For first characterizations X-ray diffraction (XRD), scanning electron microscopy (SEM), hysteresis-, current-voltage I(V)and capacitance-voltage C(V)-measurements were carried out.     

A general quantity discount and supplier selection mixed integer programming model

Recently, new models and heuristics for exploiting quantity discounts have been proposed that are applicable in classical purchasing as well as in an e-business environment and can be implemented as part of an advanced planning system. These models can now handle both the single- and multi-item case with fixed cost to be shared among several products ordered at the same point in time from a single supplier. Furthermore, the supplier selection problem is addressed, i.e., how to best exploit quantity discounts over time offered by several suppliers. Last but not least, additional constraints on the buyer’s or on the supplier’s side may be included. While so far only purpose-built heuristics have been proposed for this generalized problem, we present a linear mixed integer programming (MIP) model, which not only represents the all-units discount but also the incremental discount case. Furthermore, the objective function chosen resolves (former) conflicts among proponents of a purely cost oriented and a cash flow oriented modeling approach. Computational tests show that our model yields near optimal solutions within a given CPU time limit by making use of a standard MIP solver.     

Improving Flood Forecasting in a Developing Country: A Comparative Study of Stepwise Multiple Linear Regression and Artificial Neural Network

Due to limited data sources, practical situations in most developing countries favor black-box models in real time operations. In a simple and robust approach, this study examines performances of stepwise multiple linear regression (SMLR) and artificial neural network (ANN) models, as tools for multi-step forecasting Chindwin River floods in northern Myanmar. Future river stages are modeled using past water levels and rainfall at the forecasting station as well as at the hydrologically connected upstream station. The developed models are calibrated with flood season data from 1990 to 2007 and validated with data from 2008 to 2011. Model performances are compared for 1- to 5-day ahead forecasts. With a high accuracy, both candidate models performed well for forecasting the full range of flood levels. The ANN models were superior to the SMLR models, particularly in predicting the extreme floods. Correlation analysis was found to be useful for determining the initial input variables. Contribution of upstream data to both models could improve the forecasting performance with higher R ² values and lower errors. Considering the commonly available data in the region as primary predictors, the results would be useful for real time flood forecasting, avoiding the complexity of physical processes.     

A multi-sensor climatological view of double ITCZs over the Indian Ocean

We characterize the climatological features of the double inter-tropical convergence zones (DITCZs) over the western Indian Ocean during November–December by a synergistic analysis of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite (HOAPS III) data (1988–2005) and the National Aeronautics and Space Administration's (NASA's) A-Train data (2002–2009). We investigate rainfall, freshwater flux and cloud liquid water, cloud fraction and relative humidity over the DITCZs. In addition, the daily rainfall data from the Global Precipitation Climatology Project (GPCP) are used to document the DITCZs during the El Niño southern oscillation (ENSO) events. An analysis of the GPCP data shows that the DITCZs are clearly discernible during strong ENSO events (1997, 2002 and 2006), in sharp contrast to the DITCZs in the eastern Pacific Ocean, where they are absent during ENSOs. Further, these convergence zones on either side of the equator are of short duration, approximately 3–6 pentads during November and December. All satellite sensor data sets consistently capture the major features of DITCZs. As an accurate simulation of DITCZs in coupled global climate models remains a challenge, the results from the present study would provide a platform for evaluating these models.     

Beschreibung von Ver- und Entfestigungsvorgängen am Beispiel austenitformgehärteter Stähle mit Hilfe von Fließkurven

Fließkurven beschreiben das Formänderungsvermögen von Werkstoffen. Gleichzeitig liefern sie Informationen über die Wechselwirkung zwischen der Ver- und Entfestigung, wobei diese beiden Eigenschaften temperaturabhängig sind. Fließkurven wurden an Stählen aufgenommen, die sich im wesentlichen in ihrem Kohlenstoffgehalt unterscheiden. Die Bestimmung der Formänderungsfähigkeit erfolgte bei Temperaturen, die denen entsprechen, bei denen eine Austenitformhärtung vorgenommen wird. Die mathematische Beschreibung der Fließkurven läßt erkennen, daß zunächst mit steigender Umformtemperatur die Verfestigungsrate abnimmt. Der Kohlenstoffgehalt erhöht dagegen die Verfestigungsrate. Die dynamische Erholung wird mit wachsender Umformtemperatur beschleunigt, ebenso mit steigendem Kohlenstoffgehalt.     

Internal and external algorithms for the points-in-regions problem—the inside join of geo-relational algebra

We consider the problem of collectively locating a set of points within a set of disjoint polygonal regions when neither for points nor for regions preprocessing is allowed. This problem arises in geometric database systems. More specifically it is equivalent to computing theinside join of geo-relational algebra, a conceptual model for geo-data management. We describe efficient algorithms for solving this problem based on plane-sweep and divide-and-conquer, requiringO(n(logn) +t) andO(n(log² n) +t) time, respectively, andO(n) space, wheren is the total number of points and edges, and (is the number of reported (point, region) pairs. Since the algorithms are meant to be practically useful we consider as well as the internal versions-running completely in main memory-versions that run internally but use much less than linear space and versions that run externally, that is, require only a constant amount of internal memory regardless of the amount of data to be processed. Comparing plane-sweep and divide-and-conquer, it turns out that divide-and-conquer can be expected to perform much better in the external case even though it has a higher internal asymptotic worst-case complexity. An interesting theoretical by-product is a new general technique for handling arbitrarily large sets of objects clustered on a singlex-coordinate within a planar divide-and-conquer algorithm and a proof that the resulting “unbalanced” dividing does not lead to a more than logarithmic height of the tree of recursive calls.     

Auf dem Weg zu idealen Programmierwerkzeugen – Bestandsaufnahme und Ausblick

Zusammenfassung  Angeregt durch Robert W. Floyds Turing-Award-Lecture ,,The Paradigms of Programming“ von 1979 [6] und motiviert durch die Unzufriedenheit des Praktikers mit dem Stand der Softwaretechnik aus vielen Industrieprojekten, versucht dieser Beitrag eine Bestandsaufnahme der Programmiertechnik und identifiziert die Defizite aus Sicht der Grundprinzipien des Konstruktionsprozesses. Mit der Objektorientierung sind, besonders in den letzten Jahren, viele neue Programmiersprachen entstanden, die sowohl Wert auf schnelle Entwicklungszyklen als auch auf Erweiterbarkeit legen. Die heute haupts?chlich verwendeten Sprachen und Umgebungen sind von diesen Zielen weit entfernt. Das Entwickeln von Software ist zum einen zu kompliziert und zum anderen schmerzt die ,,semantische Lücke“ zwischen den ausdrückbaren und den erforderlichen Konzepten. Neue, viel versprechende Programmiersprachen, die sich durchweg auf Metaprogrammierung stützen, um die erforderliche semantische Erweiterbarkeit der Sprachen zu erreichen, deuten die Richtung zukünftiger Entwicklungen an.