Best linear unbiased estimators for properties of digitized straight lines

This paper considers the problem of measuring properties of digitized straight lines from the viewpoint of measurement methodology. The measurement and estimation process is described in detail, revealing the importance of a step called ``characterization' which was not recognized explicitly before. Using this new concept, BLUE (Best Linear Unbiased) estimators are found. These are calculated for various properties of digitized straight lines, and are briefly compared to previous work.     

A Chinese information processing system

The Chinese information processing system(CIPS)introduced in this paper can producegraphs,tables,flowcharts,mathematical equations,forms and also provides typesettingfacilities.The system can process not only Chinese text but also English text or a mixture ofthem.It is written in C language and runs on VAX Ⅱ/780 under Unix operating system.TheCIPS system is very easy to use and provides user-defined macro which allows abbreviationsof commonly used Chinese phrases and reduce the complexity of Chinese characters coding.     

Regulation of lactate production in Streptococcus bovis: A spiraling effect that contributes to rumen acidosis

When Streptococcus bovis was grown in batch culture with 6 g/L glucose at pH 6.7, maximum specific growth rate was 1.47 h(-1), and lactate was the primary fermentation product. In continuous culture at pH 6.7 and growth rate equal to .10 h(-1), little lactate was formed, and formate, acetate, and ethanol accounted for most of the product. When extra-cellular pH decreased to 4.7, intra-cellular pH declined to 5.4, and organisms switched back to lactate production. Intracellular concentration of fructose 1,6-diphosphate of batch culture cells was greater than 12 mM, a concentration that allowed maximal lactate dehydrogenase activity. When Streptococcus bovis was grown in continuous culture at pH 6.7, intracellular fructose-l,6-diphosphate declined to .4 mM, a concentration which gave little lactate dehydrogenase activity at pH 6.5 or greater. Decreasing pH of continuous culture to 4.7 increased intracellular fructose-1,6-diphosphate concentration to .8 mM. This concentration was still limiting if lactate dehydrogenase was assayed at pH 6.5, but nearly maximal activity was obtained when enzyme was assayed at pH 5.5. The small increase in fructose-l,6-diphosphate and decreased requirement of lactate dehydrogenase for fructose-l,6-diphosphate under acidic assay conditions, accounted for increased lactate production during low pH (4.7) continuous culture. These and other aspects of lactate regulation by Streptococcus bovis are discussed as factors leading to rumen acidosis. This pattern of regulation also helps to explain why rumen acidosis is difficult to reverse.     

Changes in the chemical composition of rabbit meat during growth

Relative growth rates of water, fat and protein by means of the allometric equation and changes in chemical composition of total meat, meat from hind leg and M. longissimus lumbaris from 1 to 20 weeks of age were studied in 320 rabbits of two strains (New Zealand White and California) and both sexes. All the chemical components showed changes in their allometric coefficients which determined variations in their relative percentages (P < 0·001) during the experimental period. Protein was characterized by a positive allometry although its rate of deposition decreased from 3-4 weeks of age. Water exhibited an important decrease in rate of deposition, passing from positive to negative allometry while, almost simultaneously, the rate of deposition of fat increased, passing from negative to positive allometry; nevertheless, the moment of change of these two components differed among the parts chemically analysed. All these changes were concentrated in a short interval of ages (3-7 weeks of age) that coincided with the one found for anatomic components of the carcass in a previous work (Deltoro & López, 1985). Significant differences (P < 0·001) for mean values were obtained among parts chemically analysed and, to a lesser degree, between lines and sexes. Meat from hind leg and M. longissimus lumbaris had a higher content of protein and a lower content of fat than the rest of the carcass meat. Relating the results to fat-free matter decreased differences but remained significant in most cases and indications of having attained chemical maturity at the end of the experimental period were obtained.     

Tomographic reconstruction from experimentally obtained cone-beam projections

Direct reconstruction in three dimensions for two-dimensional projection data has been achieved by cone-beam reconstruction techniques. In this paper explicit formulas for a cone-beam convolution and back-projection reconstruction algorithm are given in a form which can be easily coded for a computer. The algorithm is justified by analyzing tomographic reconstructions of a uniformly attenuating sphere from simulated noisy projection data. A particular feature of this algorithm is the use of a one-dimensional rather than two-dimensional convolution function, greatly speeding up the reconstruction. The technique is applicable however large the cone angle of data capture and correctly reduces to the pure fan-beam reconstruction technique in the central section of the cone. The method has been applied to data captured on a cone-beam CT scanner designed for bone mineral densitometry.