The economics of indigenous energy use: The case of northern Ireland lignite

The paper sets out an economic framework within which to judge the potential economic benefits of using newly discovered indigenous fuel reserves. It illustrates the method with extensive reference to the newly discovered deposits of lignite in Northern Ireland. For a long time, the lack of indigenous fuel supplies, together with some unfortunate decisions on fuel use, resulted in Northern Ireland having the highest energy costs of any region in the United Kingdom. Although not the bonanza it was originally thought to be, lignite offers the possibility of a secure source of fuel to power at least part of the local electricity supply system, the smallest isolated electricity supply system in western Europe.     

A parallel algorithm for approximating the minimum cycle cover

We address the problem of approximating aminimum cycle cover in parallel. We give the first efficient parallel algorithm for finding an approximation to aminimum cycle cover. Our algorithm finds a cycle cover whose size is within a factor of 0(1 +n logn/(m + n) of the minimum-sized cover usingO(log² n) time on (m + n)/logn processors.Research supported by ONR Grant N00014-88-K-0243 and DARPA Grant N00039-88-C0113 at Harvard University.Research supported by a graduate fellowship from GE. Additional support provided by Air Force Contract AFOSR-86-0078, and by an NSF PYI awarded to David Shmoys, with matching funds from IBM, Sun Microsystems, and UPS.     

Hypertensive cardiac hypertrophy--is genetic variance the missing link?

1. Hypertensive cardiac hypertrophy is a major independent predictor of adverse cardiovascular events. In man the cardiac response to increased afterload is very variable, even when ambulatory blood pressure monitoring is used. Analysis of breeding experiments using normotensive and hypertensive rat strains, human twin studies and other data indicate that genetic factors play a significant role in regulating cardiac mass; in other words, a large component of total variability is accounted for by genetic variance. 2. The observation that some patients with only mild-to-moderate hypertension exhibit gross left ventricular hypertrophy (LVH) similar to the inherited hypertrophic cardiomyopathies such as familial hypertrophic cardiomyopathy (FHC) and Friedreich's ataxia (FA) has prompted us to investigate the hypothesis that genetic factors associated with excessive myocardial hypertrophy, viz. mutations in FHC and FA genes alter the hypertrophic response of the heart to pressure overload. Here we review briefly three lines of study: (i) association analysis to test whether the allele frequencies differ in hypertensive patients with or without left ventricular hypertrophy; (ii) characterization of the cardiac manifestations of FA to understand the mechanism by which the heart is affected in a disease associated with pathology in a subgroup of neurons, and (iii) creation of transgenic models to facilitate the investigation of the interaction between hypertrophic stimuli and underlying genetic predisposition. 3. Information on the nature of the cardiac-mass-modifying genes involved may be useful not only for selecting high risk patients in strategies aimed at preventing the development of LVH, but also in opening new avenues of research on the reprogramming of cardiac myocytes to encourage them to hypertrophy in situations where cardiac muscle has been damaged or is hypoplastic.     

Compilation Methods for the Address Calculation Units of Embedded Processor Systems

An essential component of today's embedded system is an instruction-set processor running real-time software. All variations of these core components contain at least the minimum data-flow processing capabilities, while a certain class contain specialized units for highly data-intensive operations for Digital Signal Processing (DSP). For the required level of memory interaction, the parallel executing Address Calculation Unit (ACU) is often used to tune the architecture to the memory access characteristics of the application. The design of the ACU is performance critical. In today's typical design flow, this design task is somewhat driven by intuition as the transformation from application algorithm to architecture is complex and the exploration space is immense. Automatic utilities to aid the designer are essential; however, the key compilation techniques which map high-level language constructs onto addressing units have lagged far behind the emergence of these units. This paper presents a new retargetable approach and prototype tool for the analysis of array references and traversals for efficient use of ACUs. In addition to being an enhancement to existing compiler systems, the ArrSyn utility may be used as an aid to architecture exploration. A simple specification of the addressing resources and basic operations drives the available transformations and allows the designer to quickly evaluate the effects on speed and code size of his/her algorithm. Thus, the designer can tune the design of the ACU toward the application constraints. ArrSyn has been successfully used together with a C compiler developed for a VLIW architecture for an MPEG audio decoding application. The combination of these methods with the C compiler showed on average a 39% speedup and 29% code size reduction for a representative set of DSP benchmarks.     

Autonomic control of skeletal muscle vasodilation during exercise

Despite extensive investigation, the control of blood flow during dynamic exercise is not fully understood. The purpose of this study was to determine whether beta-adrenergic or muscarinic receptors are involved in the vasodilation in exercising skeletal muscle. Six mongrel dogs were instrumented with ultrasonic flow probes on both external iliac arteries and with a catheter in a branch of one femoral artery. The dogs exercised on a treadmill at 6 miles/h while drugs were injected intra-arterially into one hindlimb. Isoproterenol (0.2 microg) or acetylcholine (1 microg) elicited increases in iliac blood flow of 89.8 +/- 14.4 and 95.6 +/- 17.4%, respectively, without affecting systemic blood pressure or blood flow in the contralateral iliac artery. Intra-arterial propranolol (1 mg) or atropine (500 microg) had no effect on iliac blood flow, although they abolished the isoproterenol and acetylcholine-induced increases in iliac blood flow. These data indicate that exogenous activation of beta-adrenergic or muscarinic receptors in the hindlimb vasculature increases blood flow to dynamically exercising muscle. More importantly, because neither propranolol nor atropine affected iliac blood flow, we conclude that beta-adrenergic and muscarinic receptors are not involved in the control of blood flow to skeletal muscle during moderate steady-state dynamic exercise in dogs.     

A note on visualizing the Omega Prism

Simple techniques are described for demonstrating graphically interesting behavior of puzzles defined on finite lattices. The simple puzzles should be of interest to students and teachers who may wish to design and solve similar problems. In particular, this note describes computer graphics used to gain insight into the behavior of the solution space.     

Anthropocentrism and computers

This paper introduces the multi-dimensional concept of anthropocentrism with respect to computers, the tendency to believe that (1) computers do not possess human physical and psychological capabilities; and (2) it is not acceptable for computers to fill routinized (e.g., auto mechanic), interpretive (e.g., newspaper reporter), and persona) (e.g., baby sitter) roles traditionally held only by people. A mail survey (n = 133) of individuals in Northern California focuses on individual differences rather than differences between technologies. As suggested by the literature on ethnocentrism, experience with other cultures and education are strong predictors of the dimensions of anthropocentrism; surprisingly, experience with computers fails as a predictor.     

Conceptual level and structural complexity in language.

The Paragraph Completion Method (PCM) of D. E. Hunt et al (1971) has been used to identify conceptual level (CL) as a process of cognitive structuring that produces language behavior on the part of client and counselor. Independently, a Computer-Assisted Language Analysis System (CALAS) has been used to identify structural features of the counselor's and client's language. In an analysis of 39 exemplary protocols contained in a revised manual for the PCM, relations between ratings of CL and linguistic measures yielded by the CALAS were examined. Simple frequency of usage and the structural complexity of the language accounted for much of the variance in CL scores, but a dimension of CL independent of linguistic features also was identified. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)