Interactions between the cholinergic and dopaminergic systems during the production of ultrasonic vocalizations in rats

Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

Interactions between the cholinergic and dopaminergic system during the production of ultrasonic vocalizations in rats

Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

Understanding Continuance Intentions of Physicians with Electronic Medical Records (EMRS): An Expectancy-Confirmation Perspective

This thesis examines physicians’ satisfaction with electronic medical records (EMRs) in the post-adoption phase. More specifically, the study examines how physicians’ satisfaction with EMRs impacts on their intention to continue using as well as extend their adoption of additional functions of EMRs. Expectation-confirmation theory is used with the incorporation of perceived risk as the theoretical framework. The extended theoretical model is used to formulate eight hypotheses to aid in the understanding of physicians’ continuance intentions. A field survey of 135 Canadian physicians that utilize EMRs was performed to test the model empirically. The study found that physicians are willing to continue using and adopting additional components of EMRs. In addition, the empirical results suggest that physicians’ perceived usefulness and perceived risk impacts satisfaction, which in turn influences physicians’ continuance intentions. As well, perceived risk has an influence on physicians’ continuance intentions directly.

Forgiveness in Two Minds: Understanding Forgiveness Through Dual-Process Theory

In this thesis, I examined the relevance of dual-process theory to understanding forgiveness. Specifically, I argued that the internal conflict experienced by laypersons when forgiving (or finding themselves unable to forgive) and the discrepancies between existing definitions of forgiveness can currently be best understood through the lens of dual-process theory. Dual-process theory holds that individuals engage in two broad forms of mental processing corresponding to two systems, here referred to as System 1 and System 2. System 1 processing is automatic, unconscious, and operates through learned associations and heuristics. System 2 processing is effortful, conscious, and operates through rule-based and hypothetical thinking. Different definitions of forgiveness amongst both lay persons and scholars may reflect different processes within each system. Further, lay experiences with internal conflict concerning forgiveness may frequently result from processes within each system leading to different cognitive, affective, and behavioural responses. The study conducted for this thesis tested the hypotheses that processing within System 1 can directly affect one's likelihood to forgive, and that this effect is moderated by System 2 processing. I used subliminal conditioning to manipulate System 1 processing by creating positive or negative conditioned attitudes towards a hypothetical transgressor. I used working memory load (WML) to inhibit System 2 processing amongst half of the participants. The conditioning phase of the study failed and so no conclusions could be drawn regarding the roles of System 1 and System 2 in forgiveness. The implications of dual-process theory for forgiveness research and clinical practice, and directions for future research are discussed.

DNA-Directed DNA Polymerases Evolve From Reverse Transcriptase

Scientists have been debating for decades the origin of life on earth. A number of hypotheses were proposed as to what emerged first RNA or DNA; with most scientists are in favour of the "RNA World" hypothesis. Assuming RNA emerged first, it fellow that the RNA polymerases would've appeared before DNA polymerases. Using recombinant DNA technology and bioinformatics we undertook this study to explore the relationship between RNA polymerases, reverse transcriptase and DNA polymerases. The working hypothesis is that DNA polymerases evolved from reverse transcriptase and the latter evolved from RNA polymerases. If this hypothesis is correct then one would expect to find various ancient DNA polymerases with varying level of reverse transcriptase activity. In the first phase of this research project multiple sequence alignments were made on the protein sequence of 32 prokaryotic DNA-directed DNA polymerases originating from 11 prokaryotic families against 3 viral reverse transcriptase. The data from such alignments was not very conclusive. DNA polymerases with higher level of reverse transcriptase activity were non-confined to ancient organisms, as one would've expected. The second phase of this project was focused on conditions that may alter the DNA polymerase activity. Various reaction conditions, such as temperature, using various ions (Ni2+, Mn2+, Mg2+) were tested. Interestingly, it was found that the DNA polymerase from the Thermos aquatics family can be made to copy RNA into DNA (i.e. reverse transcriptase activity). Thus it was shown that under appropriate conditions (ions and reactions temperatures) reverse transcriptase activity can be induced in DNA polymerase. In the third phase of this study recombinant DNA technology was used to generate a chimeric DNA polymerase; in attempts to identify the region(s) of the polymerase responsible for RNA-directed DNA polymerase activity. The two DNA polymerases employed were the Thermus aquatic us and Thermus thermophiles. As in the second phase various reaction conditions were investigated. Data indicated that the newly engineered chimeric DNA polymerase can be induced to copy RNA into DNA. Thus the intrinsic reverse transcriptase activity found in ancient DNA polymerases was localized into a domain and can be induced via appropriate reaction conditions.

Hyperosmotic Stress and the Impact on Metabolite Formation and Redox Balance in Saccharomyces cerevisiae and Saccharomyces bayanus strains

Wine produced using an appassimento-type process represents a new and exciting innovation for the Ontario wine industry. This process involves drying grapes that have already been picked from the vine, which increases the sugar content due to dehydration and induces a variety of changes both within and on the surface of the grapes. Increasing sugar contents in musts subject wine yeast to conditions of high osmolarity during alcoholic fermentations. Under these conditions, yeast growth can be inhibited, target alcohol levels may not be attained and metabolic by-products of the hyperosmotic stress response, including glycerol and acetic acid, may impact wine composition. The further metabolism of acetic acid to acetylCoA by yeast facilitates the synthesis of ethyl acetate, a volatile compound that can also impact wine quality if present in sufficiently high concentrations. The first objective of this project was to understand the effect of yeast strain and sugar concentration on fermentation kinetics and metabolite formation, notably acetic acid and ethyl acetate, during fermentation in appassimento-type must. Our working hypotheses were that (1) the natural isolate Saccharomyces bayanus would produce less acetic acid and ethyl acetate compared to Saccharomyces cerevisiae strain EC-1118 fermenting the high and low sugar juices; (2) the wine produced using the appassimento process would contain higher levels of acetic acid and lower levels of ethyl acetate compared to table wine; (3) and the strains would be similar in the kinetic behavior of their fermentation performances in the high sugar must. This study determined that the S. bayanus strain produced significantly less acetic acid and ethyl acetate in the appassimento wine and table wine fermentations. Differences in acetic acid and ethyl acetate production were also observed within strains fermenting the two sugar conditions. Acetic acid production was higher in table wine fermented by S. bayanus as no acetic acid was produced in appassimento-style wine, and 1.4-times higher in appassimento wine fermented by EC-1118 over that found in table wine. Ethyl acetate production was 27.6-times higher in table wine fermented by S. bayanus, and 5.2-times higher by EC-1118, compared to that in appassimento wine. Sugar utilization and ethanol production were comparable between strains as no significant differences were determined. The second objective of this project was to bring a method in-house for measuring the concentration of pyridine nucleotides, NAD+, NADP+, NADH and NADPH, in yeast cytosolic extract. Development of this method is of applicative interest for our lab group as it will enable the redox balance of the NAD+/ NADH and NADP+/ NADPH systems to be assessed during high sugar fermentations to determine their respective roles as metabolic triggers for acetic acid production. Two methods were evaluated in this study including a UV-endpoint method using a set of enzymatic assay protocols outlined in Bergmeyer (1974) and a colorimetric enzyme cycling method developed by Sigma-Aldrich® using commercial kits. The former was determined to be limited by its low sensitivity following application to yeast extract and subsequent coenzyme analyses, while the latter was shown to exhibit greater sensitivity. The results obtained from the kits indicated high linearity, accuracy and precision of the analytical method for measuring NADH and NADPH, and that it was sensitive enough to measure the low coenzyme concentrations present in yeast extract samples. NADtotal and NADPtotal concentrations were determined to be above the lower limit of quantification and within the range of the respective calibration curves, making this method suitable for our research purposes.

Job Demands and Organizational Citizenship Behavior: The Roles of Organizational Commitment and Social Interaction

Drawing from the Job Demands-Resources (JD-R) model and research on social exchange relationships, this study investigates the impact of three job demands (work overload, interpersonal conflict, and dissatisfaction with the organization’s current situation) on employees’ organizational citizenship behavior (OCB), the hitherto unexplored mediating role of organizational commitment in the link between job demands and organizational citizenship behavior (OCB), as well as how this mediating effect might be moderated by social interaction. Using a multi-source, two-wave research design, surveys were administered to 707 employees and their supervisors in a Mexican-based organization. The hypotheses were tested with hierarchical regression analysis. The results indicate a direct negative relationship between interpersonal conflict and OCB, and a mediating effect of organizational commitment for interpersonal conflict and dissatisfaction with the organization’s current situation. Further, social interaction moderates the mediating effect of organizational commitment for each of the three job demands such that the mediating effect is weaker at higher levels of social interaction. The study suggests that organizations aiming to instill OCB among their employees should match the immediate work context surrounding their task execution with an internal environment that promotes informal relationship building.

Investigation of the role of the nucleus accumbens in amphetamine-induced 50 kHz ultrasonic vocalizations in the rat

There is extensive evidence that the mesolimbic dopamine system underlies the production of 50 kHz ultrasonic vocalizations in rats. In particular, the shell of the nucleus accumbens is associated with generation of frequency modulated 50 kHz calls (a specific type of 50 kHz call which can be subdivided into various subtypes). There is also evidence that amphetamine administered systemically preferentially increases the proportion of trill and step calls compared to other frequency modulated 50 kHz subtypes. The purpose of this study was to investigate the effect of drug administration route and the role of the nucleus accumbens shell in amphetamine-induced 50 kHz call profile in the rat. Three experiments investigated this by using subcutaneous and intra-accumbens microinjections of amphetamine, as well as procaine (a local anesthetic) blockade of the nucleus accumbens. Ultrasonic vocalizations were recorded digitally from 24 rats and were analysed for sonographic structure based on general call parameters. The results of the three experiments were partially supportive of the hypotheses. Systemic amphetamine was found to induce greater bandwidth in 50 kHz calling compared to spontaneous calls in a vehicle condition. Systemic amphetamine was also found to preferentially increase the proportion of trill and step subtypes compared to vehicle. Moreover, there was no difference in the proportions of 50 kHz subtypes resulting from intracerebral or systemic application of amphetamine. There was, however, a significant difference for bandwidth, with systemic amphetamine inducing greater bandwidth over intraaccumbens application. Procaine blockade of the nucleus accumbens shell paired with subcutaneous amphetamine produced no difference in bandwidth of calls compared with those after a vehicle pre-treatment similarly paired. There was no reduction in the proportions of trill and step 50 kHz subtypes as well, with the procaine condition showing significantly greater proportion of step calls. The results of the study support a role for the iii nucleus accumbens shell in the amphetamine-induced changes on 50 kHz call profile. They also indicate there are more regions and pathways involved in generating 50 kHz calls than the projections from the ventral tegmental area to the nucleus accumbens. The implications of this work are that frequency modulated 50 kHz subtypes may be generated by distinct neurophysiological mechanisms and may represent a profitable avenue for investigating different circuits of 50 kHz call categories in the rat.

Explaining voice behaviour: The roles of personal resources, social interdependence, and supervisor leadership style

This study contributes to current research on voice behaviour by investigating several under-explored drivers that motivate employees’ expression of constructive ideas about work-related issues. It draws from the concept of psychological climate to examine how voice behaviour is influenced by employees’ (1) personal resources (tenacity and passion for work), (2) perceptions of social interdependence (task and outcome interdependence), and (3) supervisor leadership style (transformational and transactional). Using a multi-source research design, surveys were administered to 226 employees and to 24 supervisors at a Canadian-based not-for-profit organization. The hypotheses are tested with hierarchical regression analysis. The results indicate that employees are more likely to engage in voice behaviour to the extent that they exhibit higher levels of passion for work. Further, their voice behaviour is lower to the extent that their supervisor adopts a transformational leadership style characterized by high performance expectations or a transactional leadership style based on contingent rewards and contingent punishment behaviours. The study reveals that there are no significant effects of tenacity, social interdependence, and behaviour-focused transformational leadership on voice. The findings have significant implications for organizations that seek to encourage employee behaviours that help improve current work practices or undo harmful situations.

The Influence of the Media on Shaping Perceptions of Leadership in Sport: A Within and Between Groups Design

An experimental design that included both between-group and within-group designs was used to assess media influence on perceptions of sport leadership. Participants were recruited and randomly assigned to three groups, where each group completed two separate survey sessions regarding leader personality traits and behaviours. During the second survey session, experimental Groups 1 and 2 watched a video on a separate, respective sport leader prior to filling out the survey. There were a total of 104 participants (N = 104) for the first session, and 99 (N = 99) participants completed the second session. One-way ANOVA, factorial repeated measures ANOVA, and ANCOVA were used for data analysis. Results indicate a significant change in Group 2’s results after watching the video clip, thus rejecting the null hypotheses. Results and implications are discussed, highlighting their relationships to sport and media related theories and sport management practice.

International Business Cycles: What Are the Facts?

Modern business cycle theory involves developing models that explain stylized facts. For this strategy to be successful, these facts should be well established. In this paper, we focus on the stylized facts of international business cycles. We use the generalized method of moments and quarterly data from nineteen industrialized countries to estimate pairwise cross-country and within-country correlations of macroeconomic aggregates. We calculate standard errors of the statistics for our unique panel of data and test hypotheses about the relative sizes of these correlations. We find a lower cross-country correlation of all aggregates and especially of consumption than in previous studies. The cross-country correlations of consumption, output and Solow residuals are not significantly different from one another over the whole sample, but there are significant differences in the post-1973 subsample.

Simulation-Based Finite and Large Sample Tests in Multivariate Regressions.

In the context of multivariate linear regression (MLR) models, it is well known that commonly employed asymptotic test criteria are seriously biased towards overrejection. In this paper, we propose a general method for constructing exact tests of possibly nonlinear hypotheses on the coefficients of MLR systems. For the case of uniform linear hypotheses, we present exact distributional invariance results concerning several standard test criteria. These include Wilks' likelihood ratio (LR) criterion as well as trace and maximum root criteria. The normality assumption is not necessary for most of the results to hold. Implications for inference are two-fold. First, invariance to nuisance parameters entails that the technique of Monte Carlo tests can be applied on all these statistics to obtain exact tests of uniform linear hypotheses. Second, the invariance property of the latter statistic is exploited to derive general nuisance-parameter-free bounds on the distribution of the LR statistic for arbitrary hypotheses. Even though it may be difficult to compute these bounds analytically, they can easily be simulated, hence yielding exact bounds Monte Carlo tests. Illustrative simulation experiments show that the bounds are sufficiently tight to provide conclusive results with a high probability. Our findings illustrate the value of the bounds as a tool to be used in conjunction with more traditional simulation-based test methods (e.g., the parametric bootstrap) which may be applied when the bounds are not conclusive.

Mesure du Progres Technique: Theories et Methodes

Ce Texte Constitue un Survol des Differentes Approches Destines a Mesurer le Progres Technique. Nous Utilisons une Notation Uniforme Tout au Long des Demonstrations Mathematiques et Nous Faisons Ressortir les Hypotheses Qui Rendent L'application des Methodes Proposees Envisageable et Qui En Limitent la Portee. les Diverses Approches Sont Regroupees D'apres une Classification Suggeree Par Diewert (1981) Selon Laquelle Deux Groupes Sont a Distinguer. le Premier Groupe Contient Toutes les Methodes Definissant le Progres Technique Comme le Taux de Croissance D'un Indice des Outputs Divise Par un Indice des Inputs (Approche de Divisia). L'autre Groupe Inclut Toutes les Methodes Definissant le Progres Technique Comme Etant le Deplacement D'une Fonction Representant la Technologie (Production, Cout, Distance). Ce Second Groupe Est Subdivise Entre L'approche Econometrique,La Theorie des Nombres Indices et L 'Approche Non Parametrique. une Liste des Pricipaux Economistes a Qui L'on Doit les Diverses Approches Est Fournie. Cependant Ce Survol Est Suffisamment Detaille Pour Etre Lu Sans Se Referer aux Articles Originaux.

Expenditures on Lotteries: What Do People Say and Wht They Do? a Econometric Analysis.

Underdeclarations Are Typical When Alcohol, Tobacco and Gambling Consumptions Are Questioned in Surveys. Recent Surveys on Expenditures on Lotteries Have Similar Problems: the Declared Expenditures Equal Between 60 to 65 Percent of the Revenues of the Various State-Run Lottery Entreprises. by Using the Relatively Accurate Data on the Revenue Side of This Industry One Can Deal with the Problem of Underdeclarations of Consumption Patterns in Suveys and Obtain Better Income Elasticity Estimates. the Statistical Analysis Permits to Test Specific Hypotheses on a Lottery Model Developed by Brenner, and Suggests Broader Implications Both for Future Econometric Analysis and the Confidence One Gives to Elasticity Estimates Derived From Aggregate Sectorial Data for All Consumption Expenditures.

Risk Aversion, Intertemporal Substitution, and Option Pricing

This paper develops a general stochastic framework and an equilibrium asset pricing model that make clear how attitudes towards intertemporal substitution and risk matter for option pricing. In particular, we show under which statistical conditions option pricing formulas are not preference-free, in other words, when preferences are not hidden in the stock and bond prices as they are in the standard Black and Scholes (BS) or Hull and White (HW) pricing formulas. The dependence of option prices on preference parameters comes from several instantaneous causality effects such as the so-called leverage effect. We also emphasize that the most standard asset pricing models (CAPM for the stock and BS or HW preference-free option pricing) are valid under the same stochastic setting (typically the absence of leverage effect), regardless of preference parameter values. Even though we propose a general non-preference-free option pricing formula, we always keep in mind that the BS formula is dominant both as a theoretical reference model and as a tool for practitioners. Another contribution of the paper is to characterize why the BS formula is such a benchmark. We show that, as soon as we are ready to accept a basic property of option prices, namely their homogeneity of degree one with respect to the pair formed by the underlying stock price and the strike price, the necessary statistical hypotheses for homogeneity provide BS-shaped option prices in equilibrium. This BS-shaped option-pricing formula allows us to derive interesting characterizations of the volatility smile, that is, the pattern of BS implicit volatilities as a function of the option moneyness. First, the asymmetry of the smile is shown to be equivalent to a particular form of asymmetry of the equivalent martingale measure. Second, this asymmetry appears precisely when there is either a premium on an instantaneous interest rate risk or on a generalized leverage effect or both, in other words, whenever the option pricing formula is not preference-free. Therefore, the main conclusion of our analysis for practitioners should be that an asymmetric smile is indicative of the relevance of preference parameters to price options.