Automatic h-Scaling for the Efficient Time Integration of Stiff Mechanical Systems

When solving stiff mechanical systems, implicit time integrators overestimate the error and tend to use small stepsizes due to the order reduction phenomenon. This article introduces an algorithm for the detection of stiff components that allows automatic scaling of the stepsize h in the error estimation. It is based on an investigation of the local error and applies existing embedded formulas of implicit Runge–Kutta methods. Thus, implementation and calculation effort are low. Three examples are integrated with the code RADAU5, a linear DAE in two different formulations and a slider crank mechanism.     

Examination of structural changes of polymeric amino acid-based surfactants on enantioselectivity: effect of amino acid order, steric factors, and number and position of chiral centers

In this study, a large number of polymeric chiral surfactants were examined and their performances in terms of enantiomeric resolution compared for a variety of chiral analytes. The surfactants investigated in this study include all possible dipeptide combinations of the L-form of alanine, valine, leucine, and the achiral amino acid glycine (except glycine-glycine). Also included in this study were the single amino acid surfactants of alanine, valine, and leucine as well as the single chiral center dipeptide surfactant poly(sodium undecyl-L-leucine-beta-alanine) (poly L-SULbetaA). Several different aspects of polymeric dipeptide surfactants, as they pertain to chiral separations, are examined. Some of the factors investigated in this report include the effect of position and number of chiral centers, amino acid order, and steric effects.     

Capillary electrochromatography of cholesterol and its ester derivatives

Separation of cholesterol and its ester derivatives using micellar electrokinetic chromatography is a challenge due to the extreme hydrophobicity of these compounds. In this work, an isocratic capillary electrochromatography (CEC) method has been developed to separate a complex mixture of cholesterol and its 12-ester derivatives. The proportions of mobile phase (tetrahydrofuran, acetonitrile, water), as well as the effects of acid modifiers, buffer concentrations, voltage, and temperature on the separation of cholesterol derivatives were investigated. Addition of a polymeric surfactant, poly(sodium N-undecanoyl-L-glycinate), to the mobile phase reduced migration time and improved resolution of the analytes. The CEC method developed allows baseline separation of a complex mixture of cholesterol and 12 ester derivatives in less than 40 min. Finally, the method is applied to the characterization of cholesterol, cholesterol linoleate, and cholesterol oleate extracted from atherosclerotic plaque deposits in the arterial walls of a human aorta.     

Halothane genotype, pre-slaughter handling and stunning method all influence pork quality

Seventy-six Landrace and four Large White × Landrace pigs (n=80) of 90-134 kg liveweight were randomly allocated to a 2×2×2 factorial experiment to determine the effect of halothane genotype [heterozygous for the halothane gene (Nn) and homozygous dominant (NN)], pre-slaughter handling (minimal and negative) and stunning method (CO(2) stunning and electrical) on pork quality. The rate of muscle pH decline post-slaughter of the m. longissimus thoracis et lumborum (LTL) muscle was faster in Nn pigs compared with NN pigs (0.86 and 0.30 pH units/h, respectively). Pork from Nn pigs was also paler in colour, had higher percentage drip loss and purge and lower sarcoplasmic and myofibrillar protein solubility compared with NN pigs. Pork from CO(2) stunned pigs had a lower drip loss compared to pork from electrically stunned pigs (5.80 and 7.28%, respectively?- means of both genotypes combined). Tenderness of pork assessed at 24 h post-slaughter was not influenced by genotype, pre-slaughter handling or stunning method. However, pork from Nn pigs aged for 5 days post-slaughter was less tender than NN pigs (5.84 and 4.84 kg, respectively). Pale, soft and exudative pork was produced in all negatively handled Nn pigs, regardless of stunning method. The average amount of ecchymosis-affected muscle trimmed from carcasses of electrically stunned pigs was higher compared to pigs stunned with CO(2) (65 and 0.7 g, respectively). These data indicate that although halothane status was the most important factor influencing pork quality, pre-slaughter handling and stunning method also influenced meat and carcass quality.     

"The Memory Functioning Questionnaire for assessment of memory complaints in adulthood and old age": Correction to Gilewski et al.

Reports an error in "The Memory Functioning Questionnaire for assessment of memory complaints in adulthood and old age" by Michael J. Gilewski, Elizabeth M. Zelinski and K. Warner Schaie (Psychology and Aging, 1990[Dec], Vol 5[4], 482-490). In the aforementioned article, the author note at the beginning of the article should have contained the following statement: "The Memory Functioning Questionnaire (MFQ) items that appear in the appendix at the end of this article were published previously in 'Memory Functioning Questionnaire (MFQ)' by Michael J. Gilewski and Elizabeth M. Zelinski (Psychopharmacology Bulletin, 1988, Vol. 24, No. 4, pp. 665-670). The current article reflects the construction validation, scoring, and interpretation of the MFQ more accurately than does the article that appeared in Psychopharmacology Bulletin." (The following abstract of the original article appeared in record 1991-08788-001.) The results of psychometric analyses of the Metamemory Questionnaire (MQ) of E. M. Zelinski et al (1980), developed to evaluate perception of everyday memory functioning, are presented for a sample of 343 men and 435 women (aged 16-89 yrs). Exploratory factor analysis yielded 4 correlated factors (General Frequency of Forgetting, Retrospective Functioning, and Mnemonics Usage) that accounted for 36.7% of the variance in responses to the MQ. Factor structure was invariant across age groups (16-54 vs 55-89 yrs), 2 independent samples, and over 3 yrs. Because some of the original MQ scales did not load on the factors, only 64 of the original 92 items were retained for inclusion in the Memory Functioning Questionnaire (MFQ). Internal consistency of MFQ scores is high. The MFQ is therefore reliable for evaluating memory self-appraisals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiservice platforms for data services

The potential for broadband and data services is large and continues to expand for the foreseeable future. Consideration of the cost-effective delivery and support of both new, advanced services, as well as existing services, has led to the driver for multiservice platforms (MSPs). The cost effectiveness results from the MSP potential to share network bandwidth between services, offer a potential simplification of the operational support systems (OSS), and enable new service features and functions. A generic ATM-based MSP is described in this paper where issues of service support, service interworking, operations and maintenance, and network architecture are discussed. The paper is intended as a tutorial on the concepts.     

Comparison of the fatty acids of the tunicateBotryllus schlosseri from the Black Sea with two associated bacterial strains

The fatty acid composition of the tunicateBotryllus schlosseri and of two bacterial strains found within the tunicate, namelyVibrio parahaemolyticus and of an associated but previously unreported gram positive cocci were studied. The polyunsaturated fatty acids 6,9,12-octadecatrienoic acid, 5,8,11,14,17-eicosapentaenoic acid, and 4,7,10,13,16,19-docosahexaenoic acid were particularly abundant inB. schlosseri and were not detected in the two bacterial strains found in the tunicate. Theiso/anteiso pair, 13-methyltetradecanoic acid and 12-methyltetradecanoic acid, were the principal fatty acids in the gram positive cocci, and the 9- and 11-hexadecenoic acids were particulary abundant inV. parahaemolyticus. The diunsaturated fatty acid 9,12-octadecadienoic acid was also shown to be present inV. parahaemolyticus. The fatty acid composition of a third bacterial strain, characterized as either aPseudomonas or anAlteromonas species, and shown to be present only in the sea water from the Black Sea and not inB. schlosseri, is also reported. This is the first investigation on fatty acids from Black Sea bacteria.     

An Evaluation of Random Testing

Random testing of programs has usually (but not always) been viewed as a worst case of program testing. Testing strategies that take into account the program structure are generally preferred. Path testing is an often proposed ideal for structural testing. Path testing is treated here as an instance of partition testing, where by partition testing is meant any testing scheme which forces execution of at least one test case from each subset of a partition of the input domain. Simulation results are presented which suggest that random testing may often be more cost effective than partition testing schemes. Also, results of actual random testing experiments are presented which confirm the viability of random testing as a useful validation tool.     

Arthroscopic release for chronic, refractory adhesive capsulitis of the shoulder

Idiopathic adhesive capsulitis usually responds to gentle physical therapy or, if that fails, to closed manipulation with the patient under anesthesia. In some patients, however, loss of motion may be refractory to either of these treatments and an operative release may be indicated. We are reporting on the technique and results of arthroscopic capsular release as a new alternative for the management of such patients. During a three-year period, we managed twenty-three patients who had idiopathic adhesive capsulitis that had failed to respond to physical therapy or closed manipulation. These patients had an arthroscopic anterior capsular release and received forty-eight hours of intensive physical therapy as inpatients. During the physical therapy, the patients received an interscalene regional analgesic with use of repeated nerve blocks or with a continuous infusion through an interscalene catheter. This was followed by a supervised outpatient physical-therapy program. Six patients also had an arthroscopic acromioplasty for the treatment of impingement. There were no complications related to any of the procedures. At a mean of thirty-nine months (range, twenty-four to sixty-four months) after the arthroscopic procedure, the improvement in the score of Constant and Murley averaged 48 points (range, 13 to 77 points). The mean improvement in motion was 49 degrees (range, 0 to 105 degrees) for flexion; 42 degrees (range, 10 to 80 degrees) and 53 degrees (range, 0 to 100 degrees) for external rotation in adduction and abduction, respectively; and eight spinous-process levels (range, three to fourteen levels) and 33 degrees (range, 30 to 60 degrees) for internal rotation in adduction and abduction, respectively. These gains in motion were all significant (p < 0.01) compared with the preoperative values and were within a mean of 7 degrees of the values for the contralateral, normal shoulder. We concluded that, in patients who have loss of motion that is refractory to closed manipulation, arthroscopic capsular release improves motion reliably with little operative morbidity.