Optical channel waveguides in silicon diffused from GeSi alloy

A technique for fabricating low-loss and polarisation-independent channel waveguides in silicon is reported. The waveguides are obtained by Ge-indiffusion using either a GeSi alloy or a system of alternating Ge and Si layers. Typical fabrication parameters for single-mode waveguides are given.<>     

Nutritional aspects of colon cancer

During the last decade, a substantial amount of progress has been made in the understanding of the relationship between the dietary constituents and the development of colon cancer in man. The information base is sufficiently convincing with respect to an enhancing effect as a function of total fat intake and a protective effect of certain dietary fibers in colon cancer. The populations with high incidence of colon cancer are characterized by consumption of high-dietary fat which may be a risk factor in the absence of factors that are protective, such as use of whole-grain cereals, high fibrous foods and vegetables mainly of cruciferous type. Application of the findings made thus far in colon cancer research for the general public is, therefore, to have a far-reaching impact on the major premature, killing diseases in the western world.     

Diffusivities of volatiles in concentrated solutions

Concentration profiles obtained by slicing a cylindrical gel were used to measure diffusion of volatiles in viscous aqueous dextrose solutions. The column length, slice thickness and diffusion time were optimized to maximize the repeatability of measurements, the results being very sensitive to small changes in variables. Coefficients of variation between 5 and 10% were obtained. In the presence of different concentrations of dextrose, the diffusivity of acetone decreased markedly as dextrose concentration increased. However, when the acetone concentration was varied within the range 0·6 to 13·7%, at a constant 50% (w/w) dextrose concentration, its diffusivity did not change significantly. The sliced gel system gave values of diffusivity in close agreement with those obtained by other techniques.     

Proximate Composition, Mineral Content, and Fatty Acids of Catfish (Ictalurus punctatus, Rafinesque) for Different Seasons and Cooking Methods

The effect of conventional cooking methods and the influence of season upon proximate composition, mineral, and fatty acid profile was studied in catfish (Ictalurus punctatus, Rafinesque) fillets. Seasonal (August, December, and April purchased fillets) influences were minimal. As expected, fried catfish fillets had significantly altered (P ≤ 0.05) fatty acid profiles compared to the raw and baked fillets. All three cooking treatments resulted in significant differences (P ≤ 0.05) in proximate composition and in the levels of potassium, phosphorus, magnesium, and iron. The information presented would be useful for nutrient data banks when dietary intake of such items is of interest.     

Utilization of Defatted Sesame Flour in Fermented Salami

Fermented salami was prepared containing 0, 9, 18 and 27% defatted sesame flour (DSF). Chemical and sensory analyses were performed on the products. Results indicated that DSF could be used at either the 9 or 18% level without detrimental effect upon sensory attributes but salami containing 27% DSF will have less desirable flavor.     

The influence of preparation conditions on the electrochemical behaviour of CuO in a Li/CuO cell

A dozen CuO samples prepared under various conditions and from different starting materials were evaluated as cathode materials for a primary Li/CuO cell. The “thin electrode” method was used for rapid evaluation of the samples. Both coulombic efficiency and discharge voltage depend considerably on the method of synthesis. No correlation was found between the specific surface area and the resistivity of the samples on the one hand and the cathode performance on the other. Best results were obtained from CuO prepared by the oxidation of Cu₂O under controlled temperature and time of oxidation.     

Test Technology Technical Council Newsletter

This newsletter provides information on past and upcoming events related to the IEEE Computer Society's Test Technology Technical Council and the test community.     

Egg Thiamine Status of Lake Ontario Salmonines 1995–2004 with Emphasis on Lake Trout

Alewives (Alosa pseudoharengus), the major prey fish for Lake Ontario, contain thiaminase. They are associated with development of a thiamine deficiency in salmonines which greatly increases the potential for developing an early mortality syndrome (EMS). To assess the possible effects of thiamine deficiency on salmonine reproduction we measured egg thiamine concentrations for five species of Lake Ontario salmonines. From this we estimated the proportion of families susceptible to EMS based on whether they were below the ED20, the egg thiamine concentration associated with 20% mortality due to EMS. The ED20s were 1.52, 2.63, and 2.99 nmol/g egg for Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and coho salmon (Oncorhynchus kisutch), respectively. Based on the proportion of fish having egg thiamine concentrations falling below the ED20, the risk of developing EMS in Lake Ontario was highest for lake trout, followed by coho (O. kisutch), and Chinook salmon, with the least risk for rainbow trout (O. mykiss). For lake trout from western Lake Ontario, mean egg thiamine concentration showed significant annual variability during 1994 to 2003, when the proportion of lake trout at risk of developing EMS based on ED20 ranged between 77 and 100%. Variation in the annual mean egg thiamine concentration for western Lake Ontario lake trout was positively related (p < 0.001, r² = 0.94) with indices of annual adult alewife biomass. While suggesting the possible involvement of density-dependent changes in alewives, the changes are small relative to egg thiamine concentrations when alewife are not part of the diet and are of insufficient magnitude to allow for natural reproduction by lake trout.     

On a common error in open and short circuit reliability computation

In reliability computations for complex systems subject to two kinds of failure, analysts sometimes underestimate system reliability by using a formula that actually applies only to certain simpler structures. This error occurs several times, for example, in an otherwise instructive paper by B.W. Jenney and D.J. Sherwin (ibid., vol.R-35, p.532-8, Dec. 1986). The purpose of this work is to describe the error, illustrate how it arises in practice, and offer a correction