Showing papers by "University of Victoria published in 1985"

Lucid, the dataflow programming language

Abstract: Lucid is a functional language, but one which supports variables, i.e. values which change with time. Lucid programmers can therefore use iteration (repetition) as well as recursion. The statements of a Lucid program are equations which can be thought of as defining a network of processors and communication lines. Lucid's dataflow approach to programming has more in common with that of the UNIX (TM) shell, with its filters and pipelines, than with the imperative, one-step-at-a-time approach of a conventional language like C or Pascal.

A rational design process: how and why to fake it

Abstract: Software Engineers have been searching for the ideal software development process: a process in which programs are derived from specifications in the same way that lemmas and theorems are derived from axioms in published proofs. After explaining why we can never achieve it, this paper describes such a process. The process is described in terms of a sequence of documents that should be produced on the way to producing the software. We show that such documents can serve several purposes. They provide a basis for preliminary design review, serve as reference material during the coding, and guide the maintenance programmer in his work. We discuss how these documents can be constructed using the same principles that should guide the software design. The resulting documentation is worth much more than the "afterthought" documentation that is usually produced. If we take the care to keep all of the documents up-to-date, we can create the appearance of a fully rational design process.

Minimizing User Search Time in Menu Retrieval Systems

Abstract: The optimal structuring of menu indexes in computerized information retrieval is examined. The number of alternatives per page that minimizes search time is determined as a function of the human and machine factors of search strategy, scanning time, key-press time, and computer response time. For a wide range of conditions, the optimal number of alternatives per page is in the range of from four to eight, with limiting integer values of three and four for exhaustive and self-terminating search, respectively.

Separate sodium and calcium spikes in the same axon.

Abstract: Aglantha digitale is a jellyfish (order Hydromedusae) capable of two distinct kinds of locomotion; ‘slow’ swimming which is gener ated endogenously and is used in fishing behaviour, and ‘fast’ swimming which is evoked by predators and serves for escape. Both forms of swimming are produced by contraction of the bell-shaped body wall and expulsion of a jet of water from an opening at the base of the animal. During slow swimming, the contractions are weak and the animal moves about 15 mm, roughly one body length, but during a fast swim there is a more violent contraction which can propel the animal five times as far1,2. Both forms of contraction depend on impulses in the eight giant motor axons that synapse directly with the muscle sheet making up the inner surface of the body wall3,4. We report here that the giant motor axons are able to mediate both kinds of activity because they can conduct two different sorts of impulse. Fast swimming requires a rapidly con ducted Na+-dependent action potential whereas slow swimming depends on a low amplitude Ca2+ ‘spike’. This is the first report of an axon capable of two kinds of impulse propagation and it provides a physiological function for low potential Ca2+ activation5.

The Determinants and Control of Violence in Sport

Abstract: Violence is an unfortunate and unpleasant aspect of many sporting contests. It is a challenging task to unravel the complex reasons that underly the phenomenon. As of yet this task has not been accomplished fully. This paper will assess the relative importance of a number of factors that contribute to sports violence, and will suggest remedies to the problem. A wide variety of psychological, social, situational, and moral forces are examined. The paper suggests that a powerful socialization process is the primary determinant of sports violence but that other factors also play a significant mediating role. A conceptual model of the aggression process is presented, which suggests ways to curb violent behavior. It is concluded that socialization forces, particularly reinforcement, are the most readily manipulated in order to control violence in sport.

The relationship between lactate and ventilatory thresholds: coincidental or cause and effect?

Abstract: To determine if blood lactate (LA) is the stimulus responsible for ‘breakaway’ ventilation (VE), the lactate (LT) and ventilation (VT) thresholds were monitored during one-legged cycling exercise. Ten healthy volunteer male subjects (Mean 2-legged \(\dot V_{O_{2\max } } \) =4.27 l·min−1) performed prior exercise (PE) to reduce muscle glycogen stores by cycling at 75–85% of maximal heart rate (HR max) for 60–75 min, followed by a 30 h low carbohydrate diet. Pre- and post- LT and VT tests were performed on a cycle ergometer employing a continuous protocol with increments of 16 W every 3 min. Muscle biopsies were taken from the vastus lateralis muscle before the PE ride, prior to the threshold test 24 h later, and before testing the non-exercised (NE) leg. An I.V. catheter placed in the antecubital vein was used for serial blood samples taken at rest, and during the final 30 s of each progressive load. Gas analysis was calculated every 30 s (Beckman Metabolic Measurement Cart). Biopsies (N=3) showed that the exercise and diet regimen elicited glycogen reduction which significantly (p<0.05) reduced R and the blood LA concentration in both the PE (2.62 to 1.99 mmol·l−1) and NE (2.87 to 2.26 mmol·l−1) legs at LT. At VT, LA concentrations were also significantly reduced in the PE (3.35 to 2.56 mmol·l−1) and NE (3.59 to 2.74 mmol·−1) legs. \(\dot V_{O_2 } \) and VE, however, were similar between pre- and post- tests. Results of this study suggest that plasma LA accumulation is not responsible for ‘breakaway’ ventilation during progressive exercise and that LT and VT are not a cause and effect relationship.

Distribution of Nerve Elements Showing FMRFamide-like Immunoreactivity in Hydromedusae

Abstract: Immunofluorescence tests with antisera to various peptides reveal the presence of a FMRFamide-like peptide in neurons of hydromedusae belonging to three orders. An avian pancreatic polypeptide-like peptide may also be present in certain neurons. Distribution of FMRFamide-like immunoreactivity (Fa-IR) has been studied in Proboscidactyla (O. Limnomedusae), Phialidium and Aequorea (O. Leptomedusae) and Aglantha (O. Trachymedusae). These findings are compared with results obtained with Polyorchis (O. Anthomedusae) by Grimmelikhuijzen and Spencer [J. comp. Neurol.230, 361 (1984)]. All species show Fa-IR neurons in the tentacles linked by interconnecting neurites running in the outer marginal nerve ring. A Fa-IR plexus is present in the manubrium and, except in Aglantha, this system merges with a plexus associated with the subumbrellar radial muscles. As in Polyorchis, the swimming motor neurons are unstained. In contrast to this species, only a small percentage of the neurites composing the nerve rings are stained. The giant axons of Aglantha show no Fa-IR. The cnidothylaces of Proboscidactyla contain neurons reacting with antisera to FMRFamide and APP. Present evidence suggests that in hydromedusae Fa-IR is confined to distinct subsets of neurons. These appear to be either sensory units or units supplying smooth muscles, but they are not involved in the innervation of striated muscles.

An upper bound for the k-domination number of a graph

Abstract: The k-domination number of a graph G, γk(G), is the least cardinality of a set U of verticies such that any other vertex is adjacent to at least k vertices of U. We prove that if each vertex has degree at least k, then γk(G) ≤ kp/(k + 1).

Heterogeneous estrogen receptor levels detected via multiple microsamples from individual breast cancers.

Abstract: Twenty-six surgical breast cancer specimens were subjected to multiple estrogen receptor (ER) assays with a microsample technique. In most tumors there were large variations in ER levels in samples taken from different regions of the same tumor. After correction of individual samples for differences in carcinoma content, such variations were not abolished. Nine of the 26 breast cancers, although positive overall, were devoid of ER in some regions. For ER-positive tumors the average coefficient of variation (CV) for intratumor ER levels was 86%, with a range from 25% to 200%. This is well above the CV obtained with repeat samples of homogeneous tissue (14%). These results suggest that many ER-positive cancers may be composed of cells with a variety of ER levels. An assessment of individual intratumor ER variability may have biologic and clinical significance.

Time-series measurements of hydrothermal activity on northern Juan De Fuca Ridge

Abstract: During August/September 1984, the submersible ALVIN visited a large, active hydrothermal system on the Juan de Fuca Ridge. A time-lapse camera, taking photographs every 42 minutes for six days, was deployed at an active vent to characterize the dynamic nature of this system. This report documents the growth rate of a low temperature (measured at 56°C) hydrothermal deposit and establishes that this growth is not constant; periods of substantial erosion are superimposed upon the general growth pattern. Quantitative photographic interpretation of the suspended particulate load suggests a strong diurnal component to these fluctuations. Water flow, manifest by the movement of attached worm tubes, also shows strong variations but on a semi-diurnal basis correlated to tidal motions.

Nucleoside and nucleotide inactivation of R17 coat protein: evidence for a transient covalent RNA-protein bond.

Abstract: R17 coat protein forms a specific complex with a 21-nucleotide RNA hairpin containing the initiation site for the phage replicase gene. The RNA binding activity of the protein is inhibited by prior incubation with 5-bromouridine (BrU). The inactivation occurs with pseudo-first-order kinetics, and the inactive protein is stable to dilution. RNA binding activity of the BrU-inactivated protein is restored upon incubation with dithiothreitol. Inactivation of coat protein by N-ethylmaleimide or p-(chloromercuri)-benzenesulfonate indicates that a cysteine residue is located near the RNA binding site. Since 5-bromodeoxyuridine does not inactivate coat protein, a specific binding event appears to be required before inactivation can occur. Surprisingly, unmodified cytidine nucleotides also inactivate coat protein, with a specificity similar to the modified analogues. These results are discussed with regard to the formation of a transient covalent RNA-protein bond.

Activity and movement patterns of Octopus dofleini

Abstract: Four individual Octopus dofleini were followed over a fifteen day period in their underwater habitat by sonic tracking. Octopuses had small home ranges (250 m2maximum) which were stable over the two weeks of observation. These ranges overlapped those of other octopuses extensively, and animals did not keep a constant distance from one another, which suggests they were solitary and non‐social. Activity was slightly higher at night, and was not correlated with changes in other environmental variables. The O. dofleini made frequent short hunting trips (mode 0.5 hours), tending to have more and longer excursions at night. Octopuses are predators who appear to have flexible activity and, in the short term, restricted home range areas.

Fine structure of Lasaea subviridis and Mysella tumida sperm (Bivalvia, Galeommatacea)

Abstract: Lasaea subviridis and Mysella tumida sperm resemble the primitive spermatozoan type, but exhibit several unique morphological features. L. subviridis sperm heads vary in shape and size owing to differing degrees of nuclear condensation. A fully mature, heterogenous acrosomal vesicle with an associated axial rod is present. Up to 50% of L. subviridis sperm in developing gonads have conspicuously angled flagella that propel the sperm cells in irregular helical paths. This may represent a penultimate stage in sperm development because the remainder of the sperm cells have posteriorly-directed flagella and swim in a nonhelical anterior direction. A trend toward a reduction in both nuclear condensation and swimming ability may be a long-term consequence of increasing degrees of localized, but non-internal self-fertilization in marine invertebrates that brood. Mysella tumida sperm are monomorphic and possess numerous microvilli (30–60 nm in diameter and up to 5.7 μm in length) that resemble stereocilia and radiate from the cell membrane surrounding the basal body. In this species, the sperm cell does not have an axial rod, and the complex acrosomal vesicle contains five distinct zones of varying electron opacity. One of these zones is a transverse, electron-opaque band that is apparently composed of rolled-up membrane. Following acrosomal breakdown, this membrane unfolds to cover the anterior tip of the sperm cell. Although both L. subviridis and M. tumida are hermaphroditic, the relative size of their male investments is conspicuously different. Approximately 40–50% of the M. tumida gonadal volume is testis compared with about 5% of that in L. subviridis.

The effects of heavy metal contamination on the aquatic biota of Buttle Lake and the Campbell River drainage (Canada).

Abstract: Concentrations of zinc and copper in a series of large oligotrophic lakes on Vancouver Island, Canada, have been increasing since mining operations began near the south end of Buttle lake in 1966. Declines in species diversity of both phytoplankton and periphyton have occurred since the beginning of mining activity with the disappearance of metal sensitive forms such asAsterionella andRhizosolenia. Cladoceran and calanoid copepod numbers and species diversity increase as the metal concentrations decline downstream from the mine. Bioassays carried out withDaphnia pulex show increasing toxicity downstream. Metal concentrations in Zooplankton and metallothionein concentrations in rainbow trout liver are correlated to metal concentrations in the water. The water was not acutely toxic to rainbow trout in laboratory simulations of Buttle Lake conditions or duringin situ exposures (1 month). Specific sublethal deleterious effects have not yet been determined.

Peroxidase Activity in Relation to Suberization and Respiration in White Spruce (Picea glauca [Moench] Voss) Seedling Roots

Abstract: Peroxidase (EC 1.11.1.7) activity is associated with suberization during endodermal development and metacutization in roots of white spruce (Picea glauca [Moench] Voss) seedlings. Histochemical analysis indicates a relationship between suberization and peroxidase activity, but peroxidase is ubiquitous. Increased peroxidase activity results from the induction of four anodic peroxidase isozymes in addition to quantitative increases in two anodic peroxidase isozymes. Four of these polymerized eugenol. Cold temperatures induce formation of two anodic isozymes and result in suberization. The increased peroxidase activity associated with suberization is correlated to residual respiration. In an attempt to elucidate this relationship, the effect of respiratory inhibitors on respiration and peroxidase activity are compared.

Methods for analyzing marital conflict discourse: implications of a systems approach.

Abstract: A large number of studies of family and marital conflictual interaction purport to describe relational processes, yet close examination reveals a scarcity of process analyses. Many studies are interactional or systemic in name only. Three basic criteria are proposed as necessary for the development of a systems methodology: observable, sequential, system-level behavioral descriptions. A methodological review of the literature reveals that the first criterion yielded the most abundant set of methodologies. Application of the second criterion resulted in a much smaller number, which after the third criterion dwindled to a mere handful. This review does not focus on the substantive results of these investigations but rather on the research criteria, strategies, and issues that need to be addressed if process-oriented measures are to be developed for the study of interpersonal systems.