An interactive data management system for river water quality data

Water quality data banks are needed to document the status and trends of water pollution in a country. Examples of such systems are the STORET system in the U.S., the NAQUADAT system in Canada and the EIS system in Scandinavia. All of these systems require trained personnel to help in the formulation of the inquiry and the actual querying of the system.By contrast, what is described in this paper is an on-line, interactive data management and analysis system which allows the user the direct search, update, retrieval and analysis of the data from a computer terminal. The user addresses the system in a high level language closely resembling English and has complete control over building, updating and querying the individual data banks. Almost all statistical operations can be performed on the data starting from histograms, distributions, correlations to regression, discriminant, component and spectral analysis. Commands for producing camera-ready graphs on graphic terminals are available.The system is implemented on The University of Michigan Computer System and can be accessed through local telephone numbers in more than 100 cities in the U.S. and Canada and from the major European capitals via the TELENET system. The operation of the system is illustrated on a small sample data base on the Ohio river provided by the Ohio River Sanitation Commission (ORSANCO).     

Thermische Gestaltänderung von Arbeitswalzen und ihre Ausnutzung zur Beeinflussung der Planheit von kaltgewalztem Band

Planheit von Kaltband. Kühlung und/oder Erwärmung einer Arbeitswalze, induktive Walzenerwärmung. Temperaturfelder in der Arbeitswalze, zugeordnete Wärmedehnung.     

Electronic Simulation of the Vertebrate Retina

An electronic analog model of a section of the vertebrate retina has been constructed. It is structured in 5 layers of cells corresponding to the structure of the natural retina, whereby the function and connections of the single cell models can be varied. While signal processing occurs in the first four layers by evaluating several timedependent slow potentials as positive or negative, impulse rate time functions are emitted from the ganglion cells at the retina output. Various neural networks as inputs for the 25 Ganglion cells can be realized by using various patchboard connections. Several examples for simulation results are presented which closely fit comparable neurophysiological findings.     

Significance of low water—solid ratio and temperature on the physico-mechanical characteristics of hydrates of tricalcium aluminate

Hydration characteristics are reported of tricalcium aluminate studied at 20 and 80 °C using water-solid ratios of 0.2 and 1.0. Hydration products were subjected to differential thermal analysis, thermogravimetric analysis, scanning electron microscopy, length change, porosity and pore size distribution, and micro-hardness measurements. Hydration proceeds faster at 80 °C than at 20 °C and the cubic C₃AH₆ phase is detected in the first few seconds. At 20 °C hydration occurs with the initial formation of the hexagonal phases and expansion is continuous. At higher temperatures and a water-solid ratio of 0.2, after an initial small expansion, the dimensional change is low. The product at 80 °C develops more than fourfold the hardness value developed at 20 °C. After 2 days of hydration, porosity, per cent C₃AH₆ and microhardness are 15.2%, 83% and 38.9 kg/mm²; corresponding values for the product obtained at 20 °C are 21.5%, 75% and 9.1 kg/mm². Microstructural examination of the material formed at 80 °C indicates a closely welded and continuous network of the cubic phase. These results reveal that at a low water-solid ratio and higher temperatures the formation of the cubic phase from C₃A results in an enhancement of strength.     

Nova Scotia moose mystery--a moose sickness related to cobalt- and vitamin B12 deficiency

A wasting, debilitating disease with uncertain aetiology affecting moose (Alces alces americana) in Eastern North America has been reported repeatedly ever since the 1910s. Despite the intensive studies during 1930-1960s the cause of the sickness could not be established. In the 1960s a parasitic nematode (Parelaphostrongylus tenuis) was reported as constituting a probable explanation for the sickness, although several clinical and pathological signs remained unexplained. In Sweden, a moose disease with similar signs, has been shown to be caused by molybdenosis resulting from a nutritional imbalance. The findings of this investigation were applied in Nova Scotia to determine trace element concentrations in tissues from indigenous moose. Co deficiency was found in about half of the cases and the investigation was complemented by determining the vitamin B12 level, which proved nutritional Co/vitamin B12 deficiency, further verified by an increased MMA (methylmalonic acid) level in plasma. Deficiencies were found mainly in the Tobeatic and Cape Breton Highland regions. No indications of molybdenosis or other trace element disturbances were found in Nova Scotia. Otherwise, extremely high Cd levels (148 mg Cd/kg kidney wet wt., maximum) were found, though probably not contributing to the moose sickness. The Cd burden of moose on mainland Nova Scotia was more than 50% higher than that of moose in Huntville and Alonquin (Ontario, Canada) and five- to six-fold is higher than the highest Cd levels found in Sweden. To counteract the bio-geochemical effects of Co deficiency in the moose environment, provision of Co-containing salt licks is suggested.     

Start-up activities,individual characteristics,and the regional milieu: Lessons for entrepreneurship support policies from German micro data

This paper contributes to empirical research on the role of regional policy for entrepreneurship by focusing on the link between two stylized facts that emerged from a number of studies for Germany and other countries: Entry rates differ between regions, and the propensity to become an entrepreneur is influenced by socio-demographic variables and attitudes. We develop a theoretical framework to discuss this link, and we test whether for a person of a given age, degree of schooling, attitude towards risk etc. regional variables and, therefore, regional policies, do matter for the decision to start a new business ceteris paribus. Our econometric study is based on data for 10.000 persons from a recent representative survey of the population in ten German planning regions, the Regional Entrepreneurship Monitor (REM). We use a version of the probit model that takes care of the regional stratification of the data, and the results of the nonlinear models are carefully interpreted and illustrated. We find that the propensity to step into self-employment is, among others, higher for males, unemployed, people with contacts to a role model, and with past entrepreneurial experience, who live in more densely populated and faster growing regions with higher rates of new firm formation, while risk aversion and high prices of land have the opposite impact. Interestingly, it does not matter whether the region has a left or right government. However, many implications for entrepreneurship supporting policies in German regions are discussed in the final section.Research for this paper was done as part of the project Regional Entrepreneurship Monitor REM Germany financially supported by the German Research Foundation (DFG STE 628/7-1/2 and WA 610/2-1/2). We thank two anonymous referees and the guest editors of this issue for comments that led to an extensive revision of an earlier version.     

High power density beam from narrow diode-laser arrays in axial symmetry

A multiplexing method based on narrow diode-laser arrays (DLAs) in an axially symmetric configuration is described. The use of submillimeter narrow DLAs improves beam quality considerably in the slow-axis direction compared with typical 1-cm-wide DLAs. The axially symmetric geometry is advantageous for efficient spatial, wavelength, and polarization multiplexing. With narrow DLAs and an axially symmetric geometry, a small circular focus with more than 10-kW/mm2 average power density is possible. Theoretical calculations and preliminary experimental results are presented.