Unique and unifying themes in the mechanisms regulating the expression of the arabidopsis thaliana PR-1 and Solanum tuberosum PR-10a inducible defense genes

Arabidopsis is a model plant used to study disease resistance; Solanum tuberosum or potato is a crop species. Both plants possess inducible defense mechanisms that are deployed upon recognition of pathogen invasion. Transcriptional reprogramming is crucial to the activation of defense responses. The Pathogenesis-Related (PR) genes are activated in these defense programs. Expression of Arabidopsis PR-l and potato PR-10a serve as markers for the deployment of defense responses in these plants. PR-l expression indicates induction of systemic acquired resistance (SAR). Activation of SAR requires accumulation of salicylic acid (SA), in addition to the interaction of the non-expressor of pathogenesis-related genes I (NPRI), with the TGA transcription factors. The PR-10a is activated in response to pathogen invasion, wounding and elicitor treatment. PR-10a induction requires recruitment of the Whirly I (Whyl) activator to the promoter. This locus is also negatively regulated by the silencer element binding factor (SEBF). We established that both the PR-l and PR-10a are occupied by repressors under non-inducing conditions. TGA2 was found to be a constitutive resident and repressor of PR-l, which mediates repression by forming an oligomeric complex on the promoter. The DNA-binding activity of this oligomer required the TGA2 N-terminus (NT). Under resting conditions we determined that the PR-10a is bound by a repressosome containing SEBF and curiously the activator Pto interacting protein 4 (Pti4). In the context of this repressosome, SEBF is responsible for PR-10a binding, yet rWe also showed that PR-l and PR-10a are activated by different means. In PR-l activation the NPRI NT domain alleviates TGA2-mediated repression by interacting with the TGA2 NT. TGA2 remains at the PR-l but adopts a dimeric conformation and forms an enhanceosome with NPRl. In contrast, the PR-10a is activated by evicting the repressosome and recruiting Why! to the promoter. These results advance our understanding of the mechanisms regulating PR-l and PR-10a expression under resting and inducing conditions. This study also revealed that the means of regulation for related genes can differ greatly between model and crop s

Social neuroendocrinology of competition

The relationship between testosterone concentrations and aggressive behaviour in studies of people has produced very inconsistent findings. However, one consistent fmding that has emerged is that competitive and aggressive interactions potentiate testosterone release in both human and non-human species. It has been argued that socially-induced alterations in testosterone concentrations may function to influence ongoing and/or future social behaviour. Nonetheless, few studies have empirically tested this hypothesis. The current series of experiments was designed to address the extent to which competitioninduced fluctuations in testosterone concentrations were associated with ongoing and/or subsequent social behaviour. In Study 1, men (n = 38) provided saliva samples prior to, and at the conclusion of, the Point Subtraction Aggression Paradigm (PSAP). Although baseline testosterone concentrations were not related to aggressive behaviour, there was a positive correlation between change in testosterone and aggressive behaviour such that men who were most aggressive on the PSAP demonstrated the largest increase in testosterone concentrations. Furthermore, a rise in testosterone during the PSAP predicted willingness to choose a subsequent competitive task. In Study 2, men and women provided saliva samples prior to and after competing against a same-sex opponent on the Number Tracing Task (NTT). The outcome of the competition was rigged such that half of the individuals won most of the races, while the other half lost most of the races, thus experimentally creating a winner and loser in the laboratory. Following the competitive interaction, men and women played the PSAP with their same-sex partner. Results indicated that men selected the aggressive response (but not reward or protection responses), more frequently than women. For men assigned to the loss condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour. For men assigned to the win condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour, but only among those men who scored high on trait dominance. Change in testosterone and trait dominance did not predict aggressive behaviour in women. In Study 3, men provided saliva samples prior to, during, and at the end of the PSAP. They were randomly assigned to one of four experimental conditions that differed in the extent to which they were provoked and whether they received reward for behaving aggressively (i.e., stealing points). Results indicated that baseline testosterone concentrations did not correlate with aggression in any of the experimental conditions. Consistent with Study 1, there was a positive correlation between change in testosterone and aggressive behaviour among men who were provoked, but did not receive reward for aggression (i.e., reactive condition). Men who were provoked but did not receive reward for aggression enjoyed the task the most and were more likely to choose the competitive versus non-competitive task relative to men assigned to the other experimental conditions. Also, individual differences in aggressive behaviour among these men were positively correlated with the extent to which they enjoyed the task. Together, these studies indicate that testosterone dynamics within the context of competition influence subsequent competitive and aggressive behaviours in humans and that testosterone may be a marker of the intrinsically rewarding nature of costly aggressive behaviour.

Search engine advertising in web retailing : an efficiency analysis

This study examines the efficiency of search engine advertising strategies employed by firms. The research setting is the online retailing industry, which is characterized by extensive use of Web technologies and high competition for market share and profitability. For Internet retailers, search engines are increasingly serving as an information gateway for many decision-making tasks. In particular, Search engine advertising (SEA) has opened a new marketing channel for retailers to attract new customers and improve their performance. In addition to natural (organic) search marketing strategies, search engine advertisers compete for top advertisement slots provided by search brokers such as Google and Yahoo! through keyword auctions. The rationale being that greater visibility on a search engine during a keyword search will capture customers' interest in a business and its product or service offerings. Search engines account for most online activities today. Compared with the slow growth of traditional marketing channels, online search volumes continue to grow at a steady rate. According to the Search Engine Marketing Professional Organization, spending on search engine marketing by North American firms in 2008 was estimated at $13.5 billion. Despite the significant role SEA plays in Web retailing, scholarly research on the topic is limited. Prior studies in SEA have focused on search engine auction mechanism design. In contrast, research on the business value of SEA has been limited by the lack of empirical data on search advertising practices. Recent advances in search and retail technologies have created datarich environments that enable new research opportunities at the interface of marketing and information technology. This research uses extensive data from Web retailing and Google-based search advertising and evaluates Web retailers' use of resources, search advertising techniques, and other relevant factors that contribute to business performance across different metrics. The methods used include Data Envelopment Analysis (DEA), data mining, and multivariate statistics. This research contributes to empirical research by analyzing several Web retail firms in different industry sectors and product categories. One of the key findings is that the dynamics of sponsored search advertising vary between multi-channel and Web-only retailers. While the key performance metrics for multi-channel retailers include measures such as online sales, conversion rate (CR), c1ick-through-rate (CTR), and impressions, the key performance metrics for Web-only retailers focus on organic and sponsored ad ranks. These results provide a useful contribution to our organizational level understanding of search engine advertising strategies, both for multi-channel and Web-only retailers. These results also contribute to current knowledge in technology-driven marketing strategies and provide managers with a better understanding of sponsored search advertising and its impact on various performance metrics in Web retailing.

Keyword Competition and Determinants of Ad Position in Sponsored Search Advertising

Given the significant growth of the Internet in recent years, marketers have been striving for new techniques and strategies to prosper in the online world. Statistically, search engines have been the most dominant channels of Internet marketing in recent years. However, the mechanics of advertising in such a market place has created a challenging environment for marketers to position their ads among their competitors. This study uses a unique cross-sectional dataset of the top 500 Internet retailers in North America and hierarchical multiple regression analysis to empirically investigate the effect of keyword competition on the relationship between ad position and its determinants in the sponsored search market. To this end, the study utilizes the literature in consumer search behavior, keyword auction mechanism design, and search advertising performance as the theoretical foundation. This study is the first of its kind to examine the sponsored search market characteristics in a cross-sectional setting where the level of keyword competition is explicitly captured in terms of the number of Internet retailers competing for similar keywords. Internet retailing provides an appropriate setting for this study given the high-stake battle for market share and intense competition for keywords in the sponsored search market place. The findings of this study indicate that bid values and ad relevancy metrics as well as their interaction affect the position of ads on the search engine result pages (SERPs). These results confirm some of the findings from previous studies that examined sponsored search advertising performance at a keyword level. Furthermore, the study finds that the position of ads for web-only retailers is dependent on bid values and ad relevancy metrics, whereas, multi-channel retailers are more reliant on their bid values. This difference between web-only and multi-channel retailers is also observed in the moderating effect of keyword competition on the relationships between ad position and its key determinants. Specifically, this study finds that keyword competition has significant moderating effects only for multi-channel retailers.

Interaction between stress and immunity during a week leading to competition in young athletes

This study examined changes in the salivary concentrations of immunoglobulin A (sIgA), cortisol (sC), testosterone (sT) and testosterone-to-cortisol ratio (T/C) in 23 competitive swimmers, 11-15 years old, during a week leading to competition as compared to a control (non-competitive) week. Results showed no effect of week or day, and no significant week-by-day interaction for sIgA, sC and T/C. In contrast, sT significantly decreased during the week of competition, along with a 7%, non-significant decrease in the weekly T/C. The latter suggests that the swimmers were in a catabolic state due to their training, but this did not have a negative effect on their performance Since sC did not change over the two weeks and according to the sport anxiety scale, competition stress was relatively low in these peri-pubertal athletes, it is concluded that in the absence of high cortisol levels mucosal immunity is unaffected in young athletes prior to competition.

The Political Economy of St. Catharines' Illicit Taxi Trade

The global restructuring of production has led to increasingly precarious working conditions around the world. Post-industrial work is characterized by poor working conditions, low wages, a lack of social protection and political representation and little job security. Unregulated forms of work that are defined as “irregular” or “illegal”, or in some cases “criminal,” are connected to sweeping transformations within the broader regulated (formal) economy. The connection between the formal and informal sectors can more accurately be described as co-optation and, as a subordinate integration of the informal to the formal. The city of St. Catharines within Niagara, along with much of Ontario’s industrial heartland, has been hard hit by deindustrialization. The rise of this illegal service is thus viewed against the backdrop of heavy economic restructuring, as opportunities for work in the manufacturing sector have become sparse. In addition, this research also explores the paradoxical co-optation of the growing illicit taxi economy and consequences for racialized and foreign credentialed labour in the taxi industry. The overall objective of this research is to explore the illicit cab industry as not only inseparable from the formal economy, but dialectically, how it is as an integrated and productive element of the public and private transportation industry. Furthermore the research examines what this co-optation means in the context of a labour market that is split by race.

Demolishing the Competition: The Association between Competitive Video Game Play and Aggression among Adolescents and Young Adults

The link between video game play and aggression is an important issue as video games The link between video game play and aggression is an important issue as video games are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature. are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature.

The Arabidopsis NPR1 Protein Is a Receptor for the Plant Defense Hormone Salicylic Acid

Systemic Acquired Resistance (SAR) is a type of plant systemic resistance occurring against a broad spectrum of pathogens. It can be activated in response to pathogen infection in the model plant Arabidopsis thaliana and many agriculturally important crops. Upon SAR activation, the infected plant undergoes transcriptional reprogramming, marked by the induction of a battery of defense genes, including Pathogenesis-related (PR) genes. Activation of the PR-1 gene serves as a molecular marker for the deployment of SAR. The accumulation of a defense hormone, salicylic acid (SA) is crucial for the infected plant to mount SAR. Increased cellular levels of SA lead to the downstream activation of the PR-1 gene, triggered by the combined action of the Non-expressor of Pathogenesis-related Gene 1 (NPR1) protein and the TGA II-clade transcription factor (namely TGA2). Despite the importance of SA, its receptor has remained elusive for decades. In this study, we demonstrated that in Arabidopsis the NPR1 protein is a receptor for SA. SA physically binds to the C-terminal transactivation domain of NPR1. The two cysteines (Cys521 and Cys529), which are important for NPR1’s coactivator function, within this transactivation domain are critical for the binding of SA to NPR1. The interaction between SA and NPR1 requires a transition metal, copper, as a cofactor. Our results also suggested a conformational change in NPR1 upon SA binding, releasing the C-terminal transactivation domain from the N-terminal autoinhibitory BTB/POZ domain. These results advance our understanding of the plant immune function, specifically related to the molecular mechanisms underlying SAR. The discovery of NPR1 as a SA receptor enables future chemical screening for small molecules that activate plant immune responses through their interaction with NPR1 or NPR1-like proteins in commercially important plants. This will help in identifying the next generation of non-biocidal pesticides.

Office at Port Dalhousie statement of trade upwards on the Welland Canal during the years, 1857-1861

Office at Port Dalhousie statement of trade upwards on the Welland Canal during the years (10 pages of hand drawn charts), 1857-1861.

Comparative statement of different classes of trade passing downward through the Welland Canal at Port Colborne during the years 1857-1861

Comparative statement of different classes of trade passing downward through the Welland Canal at Port Colborne during the years 1857-1861 (1 page, hand drawn chart), Jan.25, 1862.

Six months residence and rravels in México ; containing remarks onthe present state of New Spain, its natural productions, state of society, manufactures, trade, agriculture and antiquities

UANL

Trade Creation, Trade Diversion and Investment Flows: Evidence from the Canada-Chile Free Trade Agreement.

Rapport de recherche

Do National Borders Matter? Evidence for the Mercosur Trade Bloc.

Rapport de recherche