Effectiveness of data dependence analysis

Data dependence testing is the basic step in detecting loop level parallelism in numerical programs. The problem is undecidable in the general case. Therefore, work has been concentrated on a simplified problem, affine memory disambiguation. In this simpler domain, array references and loops bounds are assumed to be linear integer functions of loop variables. Dataflow information is ignored. For this domain, we have shown that in practice the problem can be solved accurately and efficiently.⁽¹⁾ This paper studies empirically the effectiveness of this domain restriction, how many real references are affine and flow insensitive. We use Larus's llpp system⁽²⁾ to find all the data dependences dynamically. We compare these to the results given by our affine memory disambiguation system. This system is exact for all the cases we see in practice. We show that while the affine approximation is reasonable, memory disambiguation is not a sufficient approximation for data dependence analysis. We propose extensions to improve the analysis. This research was supported in part by a fellowship from AT & T Bell Laboratories and by DARPA contract N00014-87-K-0828.     

Communicating processes with value-passing and assignments

A semantic theory of an imperative language which allows value-passing and assignments as a simple action prefixing is described. Three different semantic approaches are given: denotational based on the mathematical model Acceptance Trees, axiomatic based on inequations and behavioural in terms of testing. The equivalence of these different approaches is shown. The results are compared with similar results for other languages such asCSP andOccam.This work has partly been supported by the ESPRIT/BRA project Concur     

Further characterization of the behavioral effects of peripherally administered corticotropin-releasing factor in guinea pigs

Guinea pig pups were either not injected (NI) or given SC injection of either saline vehicle (SAL) or 14 micrograms of corticotropin-releasing factor (CRF). In an isolation test, mean number of vocalizations and several measures of locomotor activity were markedly lower for CRF pups than for NI or SAL controls. CRF pups defecated less than did SAL pups. No differences were found among conditions for self-grooming. Behavioral freezing was shown by only two pups in the entire study. Significantly more CRF pups displayed piloerection, eye-closing, and a characteristic crouched stance than did controls. In a defensive withdrawal test, no differences among conditions were found for the proportion of pups entering a darkened chamber or for the latency to enter the chamber; however, CRF pups entered the chamber significantly fewer times during the 60-min test than did controls. There were no differences among conditions in the distance swum or number of turns made in a forced-swim test. These results replicate our earlier findings that peripheral injection of CRF suppresses vocalizing and a measure of locomotor activity in isolated guinea pig pups and identifies a number of additional behavioral effects. Of central interest here, the results indicate that the suppression of vocalizing and locomotion during isolation is not due to an increase in competing stress-related behavior or to diminished motor capacity.     

Clinical pathways in home nutrition support

Ten liver transplant patients were studied in basal conditions and after ingestion of a standard mixed test meal. Control groups included 10 normal subjects, 10 patients with nonalcoholic liver cirrhosis, and seven kidney transplant patients. Plasma somatostatin, blood glucose, and plasma insulin, C-peptide, and glucagon were determined before and 15, 30, 45, 60, 90, 120, and 180 minutes after the start of the meal. In liver transplant patients, basal somatostatin and insulin levels were significantly lower than in cirrhotics and were comparable to those recorded in controls and in kidney transplant patients. The time course of the somatostatin secretory response after the meal was similar in any group, but the increase, evaluated as the incremental area above baseline, was significantly higher in liver transplant patients than in controls and cirrhotics and comparable to that recorded in kidney transplant patients. Insulin incremental areas were also lower than in cirrhotics and comparable to those recorded in controls and kidney transplant patients. The data suggest that in liver transplant patients an increased somatostatin response to a meal may be related to a relative beta-cell secretory defect, which in turn seems consequent to immunosuppressive treatment.     

Tempering kinetics of alloy steels as a function of quench rate and Ms temperature

The effect of quench rate on the as-quenched hardness and carbide or carbon segregate particle size was studied for two alloy steels with M_s temperatures of 310 °C and 300 °C. The quench rate was varied from 681 to 93,000 °C per second. The hardness was studied using the Vickers hardness technique and the particle size was measured using the high-resolution, small-angle X-ray scattering technique. The as-quenched hardness and particle size were both found to decrease as the quench rate increased. Analysis of the data ruled out autotempering of the martensite as a likely basis for the observed quench rate effects. The effects of aging at room temperature (20 °C) on the hardness and particle size for these alloys were also studied. The hardness and particle size were both found to increase as the aging time increased. After 24 hours of aging, the effect of quench rate disappeared in that the hardness and particle size attained were each essentially independent of quench rate. DANIEL G. HENNESSY formerly Research Associate, Department of Materials Engineering, Rensselaer Polytechnic Institute. VIJAY SHARMA formerly Research Associate, Department of Materials Engineering, Rensselaer Polytechnic Institute. This paper is based on a presentation made at the “pcter G. Winchell Symposium on Tempering of Steel” held at the Louisville Meeting of The Metallurgical Society of AIME, October 12-13, 1981, under the sponsorship of the TMS-AIME Ferrous Metallurgy and Heat Treatment Committees.     

The Health Promoting Properties of the Conjugated Isomers of α-Linolenic Acid

The bioactive properties of the conjugated linoleic acid (CLA) isomers have long been recognised and are the subject of a number of excellent reviews. However, despite this prominence the CLA isomers are not the only group of naturally occurring dietary conjugated fatty acids which have shown potent bioactivity. In a large number of in vitro and in vivo studies, conjugated α-linolenic acid (CLNA) isomers have displayed potent anti-inflammatory, immunomodulatory, anti-obese and anti-carcinogenic activity, along with the ability to improve biomarkers of cardio-vascular health. CLNA isomers are naturally present in high concentrations in a large variety of seed oils but can also be produced in vitro by strains of lactobacilli and bifidobactena through the activity of the enzyme linoleic acid isomerase on α-linolenic acid. In this review, we will address the possible therapeutic roles that CLNA may play in a number of conditions afflicting Western society and the mechanisms through which this activity is mediated.     

Effect of pasture versus indoor feeding regimes on the yield,composition, ripening and sensory characteristics of Maasdam cheese

Maasdam cheese was manufactured from standardized milk derived from each of three feeding systems: grass (GRA), grass and clover pasture (CLO), and indoor feeding of total mixed ration (TMR). Pasture‐derived cheeses had significantly lower L* (whiteness) and higher b* values (yellowness) compared to TMR‐derived cheeses. Acetate levels were significantly lower in CLO and butyrate levels significantly higher in TMR compared to the other cheeses. Grass‐fed cheese had significantly higher scores for smooth texture, ivory colour and shiny appearance compared to TMR. The influence of feed type was minimal on cheese yield, composition and on glycolysis, lipolysis and proteolysis during ripening.