900 resultados para Self‘-theory and consumer behaviour
Resumo:
Increasing citrate concentration, at constant ionic strength (30 mM) decreases the rate of cytochrome ~ reduction by ascorbate. This effect is also seen at both high (600 mM) and low (19 mM) ionic strengths, and the Kapp for citrate increases with increasing ionic strength. Citrate binds d both ferri -and ferrocytochrome ~, but with a lower affinity for the latter form (Kox . .red d = 2 mM, Kd = 8 mM) as shown by an equilibrium assay with N,N,N',N', Tetramethyl E- phenylenediamine. The reaction of ferricytochrome ~with cyanide is also altered in the presence of citrate: citrate increases the K~PP for cyanide. Column chromatography of cytochrome ~-cytochrome oxidase mixtures shows citrate increases the dissociation constant of the complex. These results are confirmed in kinetic assays for the "loose"site (Km = 20 pM) only. The effect of increasing citrate observable at the "tight" site (Km = 0.25 pM) is on the turnover number and not on the K . These results suggest a mechanism m where anion binding to cytochrome £ at the tight site affects the equilibrium between two forms of cytochrome c bound cytochrome oxidase: an active and an inactive one.
Resumo:
In the past ten years, many researchers have focussed their attention on parasites regarding the role they may play in causing variations in male secondary sexual traits and subsequent effects on female choice. Male age has also been suggested to be an important factor in female choice if old age reflects superior genes. This study investigated the effects that gregarine gut parasites, age, and diet have on the calling and mating behaviour of the male Texas field cricket, Gryllus integer. Male calling songs were recorded in the laboratory using a Digital Signal Processing Network. The song parameters measured were: pulse rate, pulse width, burst duration, pulses per burst, interburst interval, and percent missing pulses. The effects of parasite load and age on the various calling song parameters was investigated in crickets that were fed two different diets varying in nutritional quality. None of the calling song parameters were affected by either parasite load or age in either diet grou p. Courtship behaviour was ob served and recorded using an Eventlog recorder on an IBM computer in the laboratory. Females mated equally with paras(tized and unparasitized males and with old and young males The total duration and proportion of time spent performing each of 9 courtship displays were recorded for males on each diet. Only one display was affected by parasite load. Highly parasitized males fed the nutritionally inferior diet juddered for a proportionately shorter time than males with low parasite loads. Also, older males performed juddering and shaking antennae proportionally longer and juddering and raising wings for longer durations than younger males. Males that successfully mated were observed for performance of 8 post-copulatory guarding behaviour displays. None of the guarding behaviours were affected by parasite load. However, one display was affected by age, with older males performing guard turning for shorter durations than younger males. Results are discuss,ed in terms of the influence of parasites and age on female choice.
Resumo:
In this thesis I outline a critical approach to interpreting the considerable academic literature on Aboriginal women in North America. I locate the scholarship concerning Native women within an understanding of three developments related to a philosophy of science: (I) paradigmatic shifts concerning the philosophy of science, (2) materialist-idealist debates and (3) transitions in feminist theory characterized by what is tenned the shift from second to third wave feminism. My exploration of emergent themes suggests that the elements indicated above provide overlapping frameworks within which most scholarship about Indigenous women is positioned. I illustrate my finding that employing critical discourse analysis and postcolonial feminism as both method and theory provides a useful approach in attending to intersecting experiences of 'race, class, and gender.' I view these intersecting experiences as central to the socio-political positioning of Indigenous women within contemporary feminist theorizing. I conclude my thesis by reflecting on the conceptual struggles I experienced in fonnulating and organizing the thesis and the significance of my underlying epistemological position and value-orientation as both a feminist and Native woman.
Resumo:
Research has shown a consistent correlation between efficacy and sport performance (Moritz, et aI., 2000). This relationship has been shown to be dynamic and reciprocal over seasons (e.g., Myers, Payment, et aI., 2004), within games (e.g., Butt, et aI., 2003), and across trials (e.g., Feltz, 1982). The purpose of the present study was to examine selfefficacy and performance simultaneously within one continuous routine. Forty-seven undergraduate students performed a gymnastic sequence while using an efficacy measure. Results indicated that the efficacy-performance relationship was not reciprocal; previous performance was a significant predictor of subsequent performance (p < .01; f3s ranged from .44 to .67). Results further revealed significant differences in efficacy beliefs between groups with high and low levels of performance [F (1,571) = 7.16,p < .01]. Findings suggest that high levels of performance within a continuous physical activity task result in higher performance scores and higher efficacy beliefs.
Resumo:
Background: CVD is the second leading cause of death in Canada. Mastery and self-esteem are psychosocial factors, suggested to be emerging risk factors for CVD. Purpose: The purpose of the study was two-fold; first to establish whether mastery and self-esteem predicted adherence to maintenance CR; and second, whether mastery and self-esteem improved after a 6-month maintenance CR program. Methods: Data were collected at the Brock University Heart Institute. The study involved a sample of 98 participants. At intake to the program and 6-month follow-up, participants completed a questionnaire battery which included the Rosenberg Self-Esteem Scale and the Pearlin-Schooler Mastery Scale. Results: Mastery and self-esteem scores did not alter the likelihood of adherence to the CR program. Mastery and self-esteem did significantly improve after 6-months of CR amongst participants with the lowest exercise capacity. Conclusion: Maintenance CR does improve mastery and self-esteem amongst those with diminished exercise capacity.
Resumo:
While many studies have been conducted on adolescent depressive symptoms and alcohol use, much of the research has examined these behaviors separately rather than examining their co-occurrence within individuals. In the present study, adolescents (N = 4412; 49% female) were surveyed at four time points (grade 9, 10, 11, and 12) and growth mixture modeling was used to identify groups of individuals reporting various patterns of depressive symptoms and alcohol use across the high school years. Four groups were identified, including co-occurrence (higher depressive symptoms and higher alcohol use relative to peers, comprising 6.1 % of boys and 7.1 % of the girls in the sample), pure depressive symptoms (higher depressive symptoms and lower alcohol use; 12.7% of boys and 12.5% of girls), pure alcohol use (higher alcohol use and lower depressive symptoms; 20.9% of boys and 19.9% of girls), and low co-occurrence (lower depressive symptoms and alcohol use, 60.3% of boys and 60.5% of girls). Groups were compared on self-regulatory (i.e., delay of gratification) and approach behaviors. For both boys and girls, delay of gratification was the strongest predictor of group membership, with the co-occurrence group scoring the lowest and the low co-occurrence group the highest. This finding emphasizes the importance of assessing delay of gratification in the identification of high risk youth.
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Although there is a general consensus among researchers that engagement in nonsuicidal self-injury (NSSI) is associated with increased risk for suicidal behavior, little attention has been given to whether suicidal risk varies among individuals engaging in NSSI. To identify individuals with a history of NSSI who are most at risk for suicidal behavior, we examined individual variability in both NSSI and suicidal behavior among a sample of young adults with a history of NSSI (N = 439, Mage = 19.1). Participants completed self-report measures assessing NSSI, suicidal behavior, and psychosocial adjustment (e.g., depressive symptoms, daily hassles). We conducted a latent class analysis using several characteristics of NSSI and suicidal behaviors as class indicators. Three subgroups of individuals were identified: 1) an infrequent NSSI/not high risk for suicidal behavior group, 2) a frequent NSSI/not high risk for suicidal behavior group, and 3) a frequent NSSI/high risk for suicidal behavior group. Follow-up analyses indicated that individuals in the ‘frequent NSSI/high risk for suicidal behavior’ group met the clinical-cut off score for high suicidal risk and reported significantly greater levels of suicidal ideation, attempts, and risk for future suicidal behavior as compared to the other two classes. Thus, this study is the first to identity variability in suicidal risk among individuals engaging in frequent and multiple methods of NSSI. Class 3 was also differentiated by higher levels of psychosocial impairment relative to the other two classes, as well as a comparison group of non-injuring young adults. Results underscore the importance of assessing individual differences in NSSI characteristics, as well as psychosocial impairment, when assessing risk for suicidal behavior.
Resumo:
The way in which individuals seek romantic partners has changed considerably in the past decades, most notably through online dating sites (ODSs). Despite the possibility of misrepresentation amongst client users, such sites continue to grow in popularity because ODSs provide a large pool from which individuals can select and attract potential partners. While much research has been undertaken on ODSs, little empirical research has examined postsecondary students’ use of ODSs. Therefore, this study sought to investigate why postsecondary students have become involved with and how they present themselves on ODSs. The researcher surveyed 20 postsecondary students and conducted in-depth interviews with 2 participants who use ODSs. Although the limited sample prevented results from being generalized, quantitative and qualitative analyses suggest that participants became involved with ODSs for various purposes, such as seeking long-term relationships and/or marriage partners, or simply exploring or visiting ODSs out of curiosity. Findings indicate that ODS users’ physical appearance and/or “attractiveness” is considered the strongest predictor of relationship success. The study discusses how participants’ self-presentation affects outcomes of ODS usage, particularly when negative self-identification and presentation corresponding to factors such as individuals’ weight and age are taken into account.
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Psychopathy researchers have long debated the role of antisocial behaviour and criminality as part of the construct of psychopathy. The current study examined the relationship between the interpersonal and affective traits (Factor 1) of psychopathy and antisocial behaviour (a facet of Factor 2), examining possible predictors of antisocial behaviour. It was hypothesized that early environment would moderate the relationship between Factor 1 traits and antisocial behaviour. Hierarchical multiple regression analyses were used in order to test for possible moderators. Sex differences were found, where men scored higher in Antisocial Behaviour. Childhood Abuse did not moderate the relationship between Factor 1 traits and Antisocial Behaviour, but predicted higher Antisocial Behaviour scores independently. Maternal Neglect was especially influential as a risk factor, significantly interacting with Factor 1 traits to predict higher Antisocial Behaviour scores. Maternal Warmth was also important, interacting with Factor 1 in a protective fashion, predicting lower Antisocial Behaviour Scores.
Resumo:
The purpose of the present study was to examine two leadership styles of personal trainers (bland versus enriched) to evaluate their effects on exercise-related outcomes. Participants were 103 university women with no previous experience weight training. Participants were randomly assigned to one of the two leadership style conditions. They completed primary measures prior to being introduced to the personal trainer. Next, participants completed an introductory weight training session, followed by post-manipulation measures. The leadership styles were successfully manipulated. Participants in the enriched leadership style condition reported significantly higher levels of enjoyment and intention to exercise. Participants in the bland leadership style condition reported significantly higher levels of social anxiety; no differences were found for task self-efficacy, self-presentational efficacy, social physique anxiety, or handgrip performance between groups. Thus, an enriched leadership style of personal trainers can increase positive psychological outcomes.
Resumo:
Nonsuicidal self-injury (NSSI), which refers to the direct and deliberate destruction of bodily tissue in the absence of suicidal intent, is a serious and widespread mental health concern. Although NSSI has been differentiated from suicidal behavior on the basis of non-lethal intent, research has shown that these two behaviors commonly co-occur. Despite increased research on the link between NSSI and suicidal behavior, however, little attention has been given as to why these two behaviors are associated. My doctoral dissertation specifically addressed this gap in the literature by examining the link between NSSI and several measures of suicidal risk (e.g., suicidal ideation, suicidal attempts, pain tolerance) among a large sample of young adults. The primary goal of my doctoral research was to identify individuals who engaged in NSSI at risk for suicidal ideation and attempts, in an effort to elucidate the processes through which psychosocial risk, NSSI, and suicidal risk may be associated. Participants were drawn from a larger sample of 1153 undergraduate students (70.3% female) at a mid-sized Canadian University. In study one, I examined whether increases in psychosocial risk and suicidal ideation were associated with changes in NSSI engagement over a one year period. Analyses revealed that beginners, relapsed injurers, and persistent injurers were differentiated from recovered injurers and desisters by increases in psychsocial risk and suicidal ideation over time. In study two, I examined whether several NSSI characteristics (e.g., frequency, number of methods) were associated with suicidal risk using latent class analysis. Three subgroups of individuals were identified: 1) an infrequent NSSI/not high risk for suicidal behavior group, 2) a frequent NSSI/not high risk for suicidal behavior group, and 3) a frequent NSSI/high risk for suicidal behavior group. Follow-up analyses indicated that individuals in the frequent NSSI/high risk for suicidal behavior group met the clinical cutoff score for high suicidal risk and reported significantly greater levels of suicidal ideation, attempts, and risk for future suicidal behavior as compared to the other two classes. Class 3 was also differentiated by higher levels of psychosocial risk (e.g., depressive symptoms, social anxiety) relative to the other two classes, as well as a comparison group of non-injuring young adults. Finally, in study three, I examined whether NSSI was associated with pain tolerance in a lab-based task, as tolerance to pain has been shown to be a strong predictor of suicidal risk. Individuals who engaged in NSSI to regulate the need to self-punish, tolerated pain longer than individuals who engaged in NSSI but not to self-punish and a non-injuring comparison group. My findings offer new insight into the associations among psychosocial risk, NSSI, and suicidal risk, and can serve to inform intervention efforts aimed at individuals at high risk for suicidal behavior. More specifically, my findings provide clinicians with several NSSI-specific risk factors (e.g., frequent self-injury, self-injuring alone, self-injuring to self-punish) that may serve as important markers of suicidal risk among individuals engaging in NSSI.
Resumo:
This is a study of the implementation and impact of formative assessment strategies on the motivation and self-efficacy of secondary school mathematics students. An explanatory sequential mixed methods design was implemented where quantitative and qualitative data were collected and analyzed sequentially in 2 different phases. The first phase involved quantitative data from student questionnaires and the second phase involved qualitative data from individual student and teacher interviews. The findings of the study suggest that formative assessment is implemented in practice in diverse ways and is a process where the strategies are interconnected. Teachers experience difficulty in incorporating peer and self-assessment and perceive a need for exemplars. Key factors described as influencing implementation include teaching philosophies, interpretation of ministry documents, teachers’ experiences, leadership in administration and department, teacher collaboration, misconceptions of teachers, and student understanding of formative assessment. Findings suggest that overall, formative assessment positively impacts student motivation and self-efficacy, because feedback is provided which offers encouragement and recognition by highlighting the progress that has been made and what steps need to be taken to improve. However, students are impacted differently with some considerations including how students perceive mistakes and if they fear judgement. Additionally, the impact of formative assessment is influenced by the connection between self-efficacy and motivation, namely how well a student is doing is a source of both concepts.