Calcium Bioavailability from Ripening Cheddar Cheese

Calcium bioavailability to rats was compared from CaCl₂ (28 mM), CaCO₃, fresh milk, milk adjusted to pH 5.35, and Cheddar cheese. The cheese was manufactured from pasteurized bovine milk and all doses were labeled extrinsically with ⁴⁵Ca and ⁴⁷Ca and administered orally to rats. One label (⁴⁵Ca) was added to milk before cheese manufacture and the other (⁴⁷Ca) was added to the cheese 24 h prior to dosing. Calcium bioavailability was determined by: 1) absorption measured by whole body counting, and 2) availability for bone metabolism assessed by bone radioactivity measurements. Calcium absorption averaged 76.8% and was not affected by length of ripening (p>0.05). Absorption from CaCl₂, CaCO₃, fresh milk, milk at pH 5.35, and the cheeses was similar. The two methods gave similar estimates of relative bioavailability. The ratio of ⁴⁷Ca absorption to ⁴⁵Ca absorption for any cheese sample was significantly greater than 1, indicating extrinsic labels added after processing may overestimate Ca absorption from cheese.     

Scheduling Parallel Computations with Successive CPM Domains

This paper describes a functional procedure for implementation of structural engineering applications in an asynchronously scheduled multi-processor environment. A modification to the classical critical path method is proposed that permits scheduling of networks that contain conditional branching or loops. A general outline is presented, describing the functional requirements of two utility procedures that generate a priority list for scheduling tasks for the particular algorithm of interest. These list-generating utilities, operating with a driver program, work with a modified version of SCHEDULE (a list scheduler) to allocate tasks to processors in an order determined using the weighted-priority heuristic. Programming difficulties inherent in schedule implementation for both shared memory systems and loosely coupled systems (with emphasis on hypercubes) are discussed. The approach is demonstrated on the subspace iteration algorithm.     

Relative Role of Phospholipids, Triacylglycerols, and Cholesterol Esters on Malonaldehyde Formation in Fat Extracted from Chicken Meat

Fresh breast and leg meat was collected from 11-wk-old pullets fed a high protein-low fat starter ration. Lipid oxidation measured in malonaldehyde (MA) equivalents in total fat extracted from meat, and in phospholipids (PL), triacylglycerol (TG), and cholesterol ester (CE) fractions of total fat was determined by an improved TBA assay with antioxidant protection. It was found that breast meat had two-fold less fat than leg. Breast fat contained 70.1% PL, 22.2% TG, and 1.2% CE; leg fat contained 42.9% PL, 51.4% TG, and 0.8% CE. After separation by thin layer chromatography, the individual lipid classes were tested for TBA reactivity. The PL fraction was found to contribute approximately 90% of the MA measured in total fat from chicken meat.     

Design of class-based storage racks for minimizing travel time in a three-dimensional storage system

This paper deals with a new storage structure layout method called ‘cubic-in-time’, for minimizing the travel time of selected handling equipment in a three-dimensional palletized storage system. Storage-system design algorithms for minimizing travel times are described, the results are analysed, and some general conclusions are drawn.     

Optimal specialization of a maintenance workforce

This article develops an analytical method for determining an optimal specialization strategy for a maintenance workforce. The method assumes that maintenance tasks are generated by a system of statistically identical machines that experience random malfunctions and require periodic service. The impact of alternative workforce structures on system performance is evaluated with a queueing network model. Markov decision analysis is employed to determine an optimal assignment of maintenance personnel to pending tasks as the network status varies over time. A linear programming algorithm is derived to enable simultaneous optimization of specific assignment decisions and the overall workforce structure. A manufacturing example demonstrates the applicability of the method to many industrial contexts. The method is also applied to the problem of maximizing military aircraft sortie generation subject to a constraint on maintenance personnel expenditure.     

Postmortem Loss of Carnitine from Skeletal Muscle of Pork and Beef

The carnitine content of beef muscle postmortem was more than twofold higher than the content of pork muscle. For both pork and beef, carnitine was distributed among the fractions, free carnitine ? short-chain acylcarnitine > long-chain acylcarnitine concentration. Based on total carnitine content, the only loss of carnitine from pork muscle occurred as a result of cooking. Cooking also reduced total carnitine content of beef muscle. In addition, total carnitine content of the beef steaks was lower after thawing. Time in the retail case did not influence carnitine content.     

The Architecture Profession and the Public

Since the beginnings of professionalization in the nineteenth century, architects have struggled to find ways to reach a broad public. Leopold Eidlitz, one of the founding members of the American Institute of Architects, published a series of essays in The Crayon in 1858 that attempted, through the use of popular literary forms, to do just that. Eidlitz addressed the "Discourses Between Two T-Squares" to a general audience and hoped that their humor and scathing caricatures would educate non-professionals about the practical and theoretical intricacies of architecture. Eidlitz's attempt at advocacy sheds light on the long-standing difficulty that architects have creating a resonant public image.     

NEW PERSPECTIVES ON COMMUNITY‐LEVEL DETERMINANTS OF HOMELESSNESS

Understanding the root causes of homelessness is important for developing effective solutions to the problem. This fact has not gone unnoticed by researchers, who have made numerous attempts to identify the underlying structural determinants of homelessness by modeling inter‐community variation in the rate of homelessness as a function of community‐level variables. Yet, prior studies in this area have a number of serious limitations, principally their reliance on methodologically flawed estimates of the size of the homeless population. The present study addresses this and other limitations by using newly available and more reliable estimates from the U.S. Department of Housing and Urban Development to model variation in the rate of homelessness across a large and diverse sample of communities throughout the United States. In doing so, this study builds on the analysis conducted by Lee, Price‐Spratlen, and Kanan ( 2003 ), and its findings have implications for policy and future research.     

Molten-Salt Corrosion of Silicon Nitride: I, Sodium Carbonate

Corrosion of Si₃N₄ under thin films of Na₂CO₃ was investigated at 1000°C. Pure Si₃N₄ and Si₃N₄ with various additives were examined. Thermogravimetric analysis and morphology observations lead to the following detailed reaction mechanism: (I) decomposition of Na₂CO₃ and formation of Na₂SiO₃, (II) rapid oxidation, and (III) formation of a protective silica layer below the silicate and a slowing of the reaction. For Si₃N₄ with Y₂O₃ additions, preferential attack of the grain-boundary phase occurred. The corrosion of pure Si and SiC was also studied for comparison to Si₃N₄. The corrosion mechanism generally applies to all three materials. Silicon reacted substantially faster than Si₃N₄ and SiC.