Showing papers by "University of British Columbia published in 1974"

Population Cycles in Small Mammals

Abstract: Publisher Summary This chapter summarizes the current information on population cycles in small rodents It first looks at the general questions about cycles, and then discusses the demographic machinery which drives the changes in numbers And finally, analyzes the current theories which explain population cycles in rodents Population cycles in voles and lemmings are accompanied by a series of changes A few of them include fluctuations occurring in a variety of genera and species from arctic to temperate areas, from Mediterranean to continental climates, from snowy areas to snow-free areas Populations living in a wide variety of plant communities in a small geographic area all fluctuate in the same way, often in phase Survival of adult males fluctuates independently of that of adult females, when viewed on a weekly time scale Males may suffer heavy losses in the decline for a few weeks when females are surviving very well, and vice versa

Some evidence for heightened sexual attraction under conditions of high anxiety.

Abstract: Male passersby were contacted either on a fear-arousing suspension bridge or a non-fear-arousing bridge by an attractive female interviewer who asked them to fill out questionnaires containing Thematic Apperception Test pictures. Sexual content of stories written by subjects on the fear-arousing bridge and tendency of these subjects to attempt postexperimental contact with the interviewer were both significantly greater. No significant differences between bridges were obtained on either measure for subjects contacted by a male interviewer. A third study manipulated anticipated shock to male subjects and an attractive female confederate independently. Anticipation of own shock but not anticipation of shock to confederate increased sexual imagery scores on the Thematic Apperception Test and attraction to the confederate. Some theoretical implications of these findings are discussed. There is a substantial body of indirect evidence suggesting that sexual attractions occur with increased frequency during states of strong emotion. For example, heterosexual love has been observed to be associated both with hate (James, 1910; Suttie, 193S) and with pain (Ellis, 1936). A connection between "aggression" and sexual attraction is supported by Tinbergen's (1954) observations of intermixed courting and aggression behaviors in various animal species, and a series of experiments conducted by Barclay have indicated the existence of a similar phenomenon in human behavior. In one study, Barclay and Haber (196S) arranged for students in one class to be angered by having their professor viciously berate them for having done poorly on a recent test; another class served as a control. Subsequently, both groups were tested for aggressive feelings and for sexual arousal. A manipulation check was successful, and the angered group manifested signfiicantly more sexual arousal than did controls (p < .01) as measured by explicit sexual content in stories written in response

Determination of sh- and ss-groups in some food proteins using ellman's reagent

Abstract: SULFHYDRYL (SH) and disulfide (SS) groups have been widely implicated as im­ portant functional groups in many food proteins. The formation of {3-lactoglobu­ lin-K-casein complexes when milk is heated may occur through the SS inter­ change reaction (Sawyer, 1969 ). The thick gel of egg white is considered to consist of large glycoprotein molecules crosslinked by SS bonds and a reductive mechanism has been proposed to explain the thinning reaction which occurs on ag­ ing of eggs (Shenstone, 1968). Further, it is well documented that addition of SH compounds to flour drastically weakens the rheological properties of the flour (Kuninori and Sullivan, 1968 ). Interac­ tions between SS and SH groups of flour have been suggested to explain, in part, this change. A simple method for the measurement of SH and SS groups in foods would clearly be desirable. Assay procedures utilizing Ellman's reagent (Ellman, 19 59) have the advantage of being simple, rapid and direct (Kalab, 1970) and have yielded values comparable with other analytical methods for SH groups (Fernandez-Diez et al., 1964) and for SS groups (Atassi et al., 1970) in purified proteins. In this report a method for the deter­ mination of both SH and SS groups utiliz­ ing Ellman's reagent is applied to flour, egg white, milk and their products.

Supplier-Induced Demand: Some Empirical Evidence and Implications

Abstract: The professional relationship arises from the significant information differential between physician and patient, and permits the physician to exert direct, non-price influence on the demand for his own services If the economic status of the physician affects the level and direction of such influence exerted, then models of the demand for care which do not include explicit consideration of supplier behavior are incompletely specified

Practical significance of brinkman's extension of darcy's law: Coupled parallel flows within a channel and a bounding porous medium

Abstract: Problems involving fluid flow past permeable surfaces have customarily been solved by matching Darcy's Law with the Navier-Stokes equation via an empirical slip-flow boundary condition at these surfaces. The present analysis serves to place the semi-empirical theory proposed by Beavers and Joseph (1967) on a more rigorous physical and mathematical basis. It is demonstrated that the predictions of these workers may be derived independently, without having to formulate empirical boundary conditions, by employing Brinkman's extension of Darcy's Law within the porous medium. These predictions are in satisfactory agreement with experimental data, thereby providing a quantitative verification of Brink-man's equation to complement its theoretical verification presented recently by several authors. On a habituellement resolu les problemes relatifs a l'ecoulement de fluides au-dela de surfaces permeables en appariant la loi de Darcy avec l'equation de Navier et Stokes, au moyen d'une condition-limite empirique d'ecoulement de glissement aux dites surfaces. L'analyse actuelle a pour but de placer la theorie semi-empirique proposee en 1967 par Beavers et Joseph sur une base physique et mathematique rigoureuse. On demontre qu'on peut obtenir independemment les previsions de Beavers et Joseph, sans qu'il ne faille formuler des conditions-limites empiriques, en utilisant l'extension faite par Brinkman de la loi de Darcy dans le milieu poreux. Lesdites previsions concordent d'une maniere satisfaisante avec les donnees experimentales; cela fournit une verification quantitative de l'equation de Brinkman, qui complete la verification theorique qu'ont presentee recemment plusieurs auteurs.

Colonial Nesting and Social Feeding as Strategies for Exploiting Food Resources in the Great Blue Heron (Ardea Herodias)

Abstract: In this paper I present data collected to test certain predictions arising from the hypothesis that colonial nesting and social feeding in birds are adaptations that enhance the efficiency of exploitation of unpredictable food supplies. The hypothesis suggests that individuals benefit from nesting in colonies because they have the opportunity to learn about good feeding areas by following other birds from the nesting colony to the feeding grounds. If a bird is unsuccessful on one foraging trip, it will observe and follow more successful birds on subsequent trips; in this way the colony acts as an 'information centre'. I collected two types of data to test this idea as applied to the Great Blue Heron (Ardea herodias). (i) I recorded flights of parent birds. (ii) I measured the rate of food intake of birds hunting for food in flocks of different sizes. The analysis of foraging flights from the colony showed the following: (a) The birds used different feeding grounds on different days; this suggests that the food supply is ephemeral. (b) The birds tended to leave the colony in groups, which would be expected if they were following each other. (c) Birds from neighbouring nests tended to use the same feeding grounds and tended to leave the colony in groups (within the overall grouping of the colony as a whole). This would be expected if birds mainly copy their near neighbours. All these results support the idea of an information centre. I did not collect any data on whether successful birds were being followed by unsuccessful ones, but the data do seem to show that birds follow one another. On the feeding grounds, I showed by use of models that herons are attracted to feed in areas where there are other birds, and that they are more attracted by a group than by a single bird. If flock feeding helps in locating good feeding places, we can expect that flock birds would do better in terms of food intake than solitary individuals. A step-wise multiple regression showed that rate of food intake of a bird (grams of fish caught per minute) is an asymptotic function of flock size. A bird in a flock of 20 gets about 5 times as much food per minute as a solitary bird. Further, the percent success (i.e. strikes resulting in a capture) is higher in flocks, and the coefficient of variation of feeding rate is lower. Thus flock birds get more food for relatively less effort and stand a smaller chance of doing very badly in terms of food intake. I discuss various possible explanations of the advantage of the flock birds, and conclude that it is not a result of searching harder, less 'nervousness' of predators or stirring up the fish to make them easy to catch. It is a consequence of the fact that flocks only build up where feeding conditions are good. I present a simple graphical model to show how this happens. In conclusion, my results support the idea that colonial nesting and social feeding are adaptations concerned with finding food, but there are also other factors involved in the evolution of sociality in ardeids and other birds.

Schooling behavior in the guppy (poecilia reticulata): an evolutionary response to predation.

Abstract: Many marine and freshwater fish move about their environment in a cohesive group called a school and the question, \"why do fish school?\", has often been raised (e.g., Cushing and Harden Jones, 1968; Weihs, 1973). In numerous species schooling is thought to have evolved primarily as an antipredator strategy but few experimental data are available to refute or support this hypothesis (Brock and Riffenburgh, 1960; Manteifel' and Radakov, 1961; Williams, 1964; Breder, 1967; Shaw, 1970). This report presents a new source of evidence favoring an antipredator role for schooling. Because most evolutionary changes occur imtially at the population or subpopulation level, studies of intraspecific (geographic) variation may yield valuable clues to the adaptive significance of schooling behavior. Natural populations of a small tropical freshwater fish, the guppy (Poecilia reticulata) , provide excellent material for studying behavioral responses to predation. In the Northern Range Mountains of Trinidad, West Indies, several geographically isolated (no interconnecting freshwater) and semi-isolated populations of guppies are exposed to different intensities of predation by other fish species (Haskins et al., 1961; Seghers, 1973; Liley and Seghers, 1974). In some rivers predation by large characid and cichlid piscivores, notably Hoplias malabaricus and Crenicichla alta, is severe. In other rivers these predators are absent and a smaller, carnivorous cyprinodontid fish, Rivulus hartii, is the major predator. In a few rivers Rivulus density is very low and guppies enjoy virtual freedom from fish predation. (Detailed measurements of other environmental variables are in Seghers, 1973, and Liley and Seghers, 1974.) I made observations on the schooling tendencies of 5 populations in the Northern Range area (Table 1). The tendency for fish to remain together was estimated semi-quantitatively. These observations were supplemented with observations on wild fish placed in aquaria and outdoor pools. Schooling is poorly developed in the Upper Aripo and Paria R. The most common social groups involve fish engaged in courtship activity (e.g., three males following and displaying to a female). These groups do not persist for more than a few

Persistent Seizure Susceptibility and Recurrent Spontaneous Seizures in Kindled Cats

Abstract: Summary Daily unilateral electrical stimulation of initially subconvulsive amygdala resulted in progressive development of seizures (kindling) in cats, culminating in generalized convulsive seizures of focal onset that could occur spontaneously. Kindled cerebral epileptogenicity persisted for up to 12 months and was characterized by (1) interictal spike discharges of consistent morphology and localization, and (2) an “all or none” response to stimulation at the generalized seizure triggering threshold. Pentylenetetrazol (Metrazol) enhanced the frequency of interictal discharge without changing its localization or morphology, and caused generalized seizures with focal onset exactly like those produced by unilateral stimulation of the amygdala. These findings indicate that repeated electrical stimulation of amygdala produces widespread alteration of brain function resulting in a permanent state of epileptogenicity. Kindling thus qualifies as an experimental model reminiscent of certain types of human epilepsy. REsume La stimulation electrique quotidienne de l'amygdale qui etait initialement subconvulsive donnait lieu progressivement a des crises (“sensibilisation,” kindling) aboutissant a des crises convulsives a debut focal secondairement generalisees, et pouvant survenir spontanement. Cet etat de sensibilisation cerebrale predisposant a l‘epilepsie, persiste jusqu’a 12 mois et se caracterise (1) par des decharges intercritiques de pointes de morphologie et localisation constantes, et (2) par une reponse de type “tout ou rien”a une stimulation seuil declenchant des crises generalisees. Le pentylenetetrazol (Metrazol) augmente la frequence des decharges de pointes intercritiques sans toutefois modifier leur topographie et leur morphologie et provoque des crises a debut focal avec generalisation secondaire exactement identiques a celles produites par la stimulation unilaterale de l'amygdale. De telles donnees indiquent que des stimulations electriques repetees de l'amygdale produisent une alteration cerebrale diffuse, responsable d'un etat permanent d‘epileptogenicite. Cet etat (“kindling”) se pose done comme un modele experimental qui rappelle certaines formes d’epilepsie chez I'homme. RESUMEN La estimulacion electrica unilateral de una amigdala, previamente subconvulsiva, produjo el desarrollo progresivo de ataques en gatos, culminando en ataques generalizados de comienzo focal, que podian ocurrir espontaneamente. Este tipo de epileptogenesis “provocada” (“kindling”= eneender) persiste hasta 12 meses y se caracteriza por (1) descargas interictales de puntas de morfologia y localizacion persistente, y (2) una respuesta “todo o nada” con estimulacion a umbrales que desencadenan ataques generalizados. El pentilenetetrazol (Metrazol) aumento la frecuencia de interictales de puntas sin modificar su localizacion o morfologia y produjo ataques generalizados de comienzo focal identicos a los producidos por estimulacion unilateral de la amigdala. Estos hallazgos indican que la estimulacion repetida de la amigdala produce alteraciones diseminadas de la funcion cerebral que se traducen en un estado permanente de epileptogenesis. Asi pues, “kindling” representa un modelo experimental aceptable que recuerda ciertos tipos de epilepsyia humana. ZUSAMMEnfassung Tagliche einseitige elektrische Stimulation des Amygdalon, die anfangs unterhalb der Krampfschwelle lag, fuhrte zur allmahlichen Ausbildung von Krampfen (“kindling”– Krampfbahnung, triggerung) bei Katzen. Sie kulminierten in generalisierten Krampfen mit fokalem Beginn, die auch spontan auftreten konnten. Die so aufgeschaukelte cerebrale Anfallsbereitschaft hielt bis zu 12 Monate an. Sie ist durch folgende Befunde charakterisiert: (1) Interiktale spike-Entladungen gleichbleibender Morphologie und Lokalisation; (2) “Alles oder Nichts”– Antwort auf Stimulation im Bereich der Schwelle fur die Auslosung generalisierter Anfalle. Pentylentetrazol (Metrazol) verstarkte die Haufigkeit der Interiktale spike-Entladungen, ohne dass sich ihre Lokalisation oder Morphologie anderte und verursachte generalisierte Krampfe mit fokalem Beginn, die genau denen glichen, die durch einseitige Stimulation des Amygdalon hervorgerufen werden konnten. Die Befunde sprechen dafur, dass wiederholte elektrische Stimulation des Amygdalon eine ausgedehnte Veranderung der Hirnfunktion hervorrufen kann, die in einem anhaltendem Zustand der Anfallsbereitschaft resultiert. Das “kindling,” die Anfallsbahnung durch repetitive elektrische Stimulation, zeight sich damit als experimentelles Modell, das an bestimmte Typen der Epilepsie beim Menschen erinnert.

Urban graffiti as territorial markers

Abstract: Wall graffiti can be indicators of attitudes, behavioral dispositions, and social processes in settings where direct measurement is difficult. The autographed inscriptions of inner city “graffiti kings”in Philadelphia are analyzed in terms of their style, motivation, and preferred setting. Graffiti written by teenage gangs delineate their turf or area of control; their content may indicate contested space and gang violence. Graffiti in an ethnic neighborhood identify tension zones related to social change.

Computation of electromagnetic transients

Abstract: Switching operations, faults, and other disturbances produce surges on transmission lines and oscillations in transformer and generator windings. Such electromagnetic transients have primarily been studied with transient network analyzers since the late 1930's. In recent years, digital computer programs have been de-. veloped which make simulation by digital computer competitive. The solution techniques of such programs are described, and their usefulness is illustrated with practical examples. Possibilities for further improvements are mentioned.

X-ray photoelectron spectra of cobalt compounds

Abstract: The X-ray photoelectron spectra of a variety of cobalt(II) and cobalt(III) complexes have been investigated. Intense satellite lines were observed for the 2p, 3s and 3p peaks in the case of the high spin cobalt(II) compounds, but not for low spin cobalt(III) complexes. The satellites of the 2p levels are best explained as arising from shake-up processes, whereas those of the 3s and 3p levels are thought to arise largely from multiplet (exchange) splitting of the levels. Multiplet splitting of the 2p level is small and responsible for an increase in the doublet separation of the 2p1/2, 2p3/2 spin-orbit levels of the high spin cobalt(II) compounds. The chemical shifts for cobalt differ for the 2p, 3s and 3p levels of the high spin cobalt(II) compounds. Those of the 2p and 3p levels of diamagnetic cobalt(III) and low spin cobalt(II) complexes are equal. The difference in the case of the high spin cobalt(II) compounds is thought to be due to the presence of unpaired 3d electrons.

Phonological rules in young children

Abstract: There are very general phonological processes which appear to operate in one form or another when any child learns a first language. This study attempts to outline and exemplify the most general of these, e.g. the reduction of consonant clusters, the deletion of unstressed syllables. In addition, the study criticizes the point of view that phonological development consists primarily of the child substituting one sound for another. Rather, phonological development reflects very general processes that affect entire classes of sounds. Lastly, the study suggests that identifying general rules can ultimately lead to more insightful information concerning separate strategies that individual children follow.

The Conscience of Huckleberry Finn

Abstract: In this paper, I shall present not just the conscience of Huckleberry Finn but two others as well. One of them is the conscience of Heinrich Himmler. He became a Nazi in 1923; he served drably and quietly, but well, and was rewarded with increasing responsibility and power. At the peak of his career he held many offices and commands, of which the most powerful was that of leader of the S.S.—the principal police force of the Nazi regime. In this capacity, Himmler commanded the whole concentration-camp system, and was responsible for the execution of the so-called ‘final solution of the Jewish problem’. It is important for my purposes that this piece of social engineering should be thought of not abstractly but in concrete terms of Jewish families being marched to what they think are bath-houses, to the accompaniment of loud-speaker renditions of extracts from The Merry Widow and Tales of Hoffman, there to be choked to death by poisonous gases. Altogether, Himmler succeeded in murdering about four and a half million of them, as well as several million gentiles, mainly Poles and Russians.

Representations of Hecke Algebras of finite groups with BN-Pairs of classical type

Abstract: . Le t G be a f i n i t e group w i t h BN-pair and Coxeter system (17, R) . Le t A be the gener i c r i n g cor respond ing to (W, R) i n the sense of T i t s , de f i ned over the po l ynomia l r i n g D = Qfu^, r e R ] . Le t k be any f i e l d of c h a r a c t e r i s t i c z e r o . For the homomorphism ' k de f ined by ^(u^) = q^, the index parameters of G, the s p e c i a l z e d a lgeb ra A^ ^ i s i somorphic to the Hecke a l geb ra ^ ( G , B) o f G w i t h respec t to a B o r e l subgroup B of G, w h i l e f o r the s p e c i a l i z a t i o n de f i ned b y . r e R, A^ ^ i s i somorph ic to the group a l geb ra kW. As G the Hecke a lgeb ra H^(G, B) a f f o rds the induced r e p r e s e n t a t i o n 1^, the G i r r e d u c i b l e r ep resen ta t i ons of G appear ing i n 1 can be obta ined from the r ep resen ta t i ons o f B) . I n t h i s t h e s i s , we o b t a i n a l l the i r r e d u c i b l e r e p r e s e n t a t i o n s , de f i ned over the quo t i en t f i e l d of D, o f the gene r i c r i n g cor respond ing to a Coxeter system of c l a s s i c a l t ype . The method employed i n v o l v e s a g e n e r a l i z a t i o n of Young's c o n s t r u c t i o n of the semi-normal ma t r i x r e p r e s e n t a t i o n s of the symmetric group. We a l so ob t a i n an e x p l i c i t formula f o r the gener i c degree o f these r ep resen ta t i ons i n terms of the hook lengths of Young diagrams. Thus the degrees of a l l the i r r e d u c i b l e c o n s t i t u e n t s of 1 are ob ta ined f o r the a 1 2 1 2 1 2 f a m i l i e s of Cheva l l ey groups A^(q ) , B £ ( q ) , A 2 £ ( q ) , ^ £ 1 ^ ) » D £ ^ Q ^ and f o r D^(q), £ odd. A l s o , most o f the degrees are obta ined f o r D 0 (q ) , I even. '

Isolation of heavy metal binding proteins from marine vertebrates

Abstract: Cadmium binding proteins have been isolated from liver homogenates of marine vertebrates by ultracentri fugation and gel filtration. Liver samples of the Atlantic grey seal Halichoerus grypus and the Pacific fur seal Callorhinus ursinus contain measurable quantities of cadmium binding protein. The copper rock fish Sebastodes caurinus showed an increase in hepatic cadmium binding protein on administration of CdCl2, in agreement with the known inducible nature of the protein isolated from terrestrial animals. The apparent molecular weights of the isolated proteins were 9000 for the grey seal, 10,000 for the fur seal, and 11,000 for the copper rock fish, as determined by gel filtration.

The Broadening of He I lines including ion dynamic corrections, with application to λ4471Å

Abstract: A theory of the broadening of He I lines with forbidden components is developed. The theory takes into account the effects of dynamic ion broadening and is valid at low densities where the forbidden line is reasonably well isolated. Good agreement with experiment and with calculations by Lee (1972) was obtained when the theory was applied at a wavelength of 4471 A. Tables of these data are given and are extended into the line wings beyond the extent of previous tabulations. Reasons for agreement with Lee data are discussed in detail. The density level above which the static ion theory is adequate is defined. A simple numerical profile of allowed lines is also obtained, taking into account dynamic ion effects.

Deficits in instrumental responding after 6-hydroxydopamine lesions of the nigro-neostriatal dopaminergic projection

Abstract: Rats subjected to bilateral injections of 6-hydroxydopamine (8 μg) into the zona compacta of the substantia nigra completely failed to learn either a one-way active avoidance response or a simple approach response for food reinforcement. The neurotoxic lesions reduced striatal dopamine and tyrosine hydroxylase activity to less than 10 percent of control levels. A significant loss of hypothalamic norepinephrine was also produced by these lesions suggesting that this procedure also destroyed part of the ventral noradrenergic bundle. When bilateral lesions of the latter pathway were made caudal to the substantia nigra, so that similar losses were produced in hypothalamic norepinephrine levels without reducing striatal tyrosine hydroxylase activity, normal acquisition of both avoidance and appetitive responses were observed. In another experiment, almost complete retention of avoidance responding was obtained if the animals were overtrained on this response prior to the bilateral nigral lesions. These results suggest that the nigro-neostriatal dopaminergic projection may play an important role in the acquisition of learned instrumental responses.