The degree to which biotic interactions influence invasion success may partly depend on the evolutionary relationship between invaders and native species. In particular, since host-use by enemies such as invertebrate herbivores and fungal pathogens tends to be phylogenetically conserved, exotic plants that have close native relatives in the invaded range should be more likely to interact with enemies. In this thesis, I explore this idea using a series of experiments and field surveys at nested taxonomic levels. My results indicate that exotics from multiple plant families experience lower damage if their average phylogenetic distance from locally co-occurring native family members is higher. I then demonstrate that within the Asteraceae, foliar and capitular damage are lower on exotic compared to native species. Both damage types had a relatively large phylogenetic component, but did not decline with phylogenetic distance to native or exotic confamilials. Finally, I show that communities with versus without close relatives are unlikely to differ in resistance to the novel invader, Solidago virgaurea: biotic resistance imposed by competitors, generalist vertebrates, and specialist invertebrates resulted in similar patterns of damage and mortality regardless of the presence of congeneric natives. In some cases, effects of biota were positive: growth of S. virgaurea seedlings in soils collected near congeneric natives was enhanced more than in soils from communities where congenerics were absent. Overall, these results suggest that biotic interactions between exotic and native species can be phylogenetically structured, although trends based on distance measures tend to be weak. In some cases, damage does decline with phylogenetic distance to native species; however this trend is unlikely to be a strong force limiting invasion or structuring plant communities. These results have significant implications for current theories of invasion biology including the "Enemy Release Hypothesis" and "Darwin's Naturalization Hypothesis", as well as for community phylogenetics.

Thesis (M.A.)--St. Bernard's Institute, Childs, NY, 1997. / Abstract. Includes bibliographical references (leaves 142-146).

A sinalização, formação e descoberta de preços agrícolas são adequadas se refletem rapidamente todas as informações recebidas pelos seus participantes. Então, quando o mercado é eficiente, possibilita eficiência alocativa, redução de imprecisão nas decisões dos agentes e dos custos informacionais. Entretanto, os agentes do agronegócio podem tomar decisões errôneas de produção, comercialização e estocagem, sujeitas ao conjunto de informações incompletas contidas nos preços passados, se os mercados forem não eficientes. Nesse contexto, o objetivo geral foi analisar a eficiência dos mercados futuros de commodities. Para atingi-lo, estruturou-se esta pesquisa em três ensaios. No primeiro, objetivou-se testar a hipótese de passeio aleatório a contratos futuros agropecuários negociados na BM&FBOVESPA. Refutá-la significa possível previsibilidade e, por conseguinte, os mercados não seriam fracamente eficientes. Correlações seriais e testes de razão de variância foram utilizados para verificá-las. Os resultados deram suporte à hipótese de passeio aleatório nos mercados futuros de café e da soja, eficientes na forma fraca, e evidências contrárias foram encontradas nos mercados do boi gordo, milho e etanol. No segundo, o objetivo foi investigar a eficiência e formações de clusters nos contratos futuros do complexo soja (soja, farelo de soja e óleo de soja) negociados nas bolsas de commodities: argentina, brasileira, chinesa, indiana, japonesa, norte-americana e sul-africana. Com base na métrica obtida por distância euclidiana de razões de variância, evidenciaram-se dependências similares dos mercados, as quais podem ser interpretadas como efeito espraiamento da eficiência informacional. Os agentes devem, portanto, manter percepções em relação aos diversos mercados devido às sinalizações interdependentes dos preços. No terceiro, objetivou-se analisar a eficiência dos mercados futuros agropecuários brasileiros, sob a hipótese adaptativa de mercado. Utilizando propostas recentes à não linearidade e razão de variância, encontrou-se que as elevadas rejeições à hipótese de diferença martingal se encontram nos mercados em que as intervenções governamentais se fazem presentes: milho e etanol. Nos mercados de café, boi gordo e soja ocorreram menores rejeições à hipótese martingal e, portanto, houve maior eficiência informacional. Essas evidências--consistentes com a hipótese adaptativa dos mercados--justificam operações de hedge dinâmicas, bem como a gerência de carteiras de investimentos de forma ativa. / Agricultural prices\' formation, discovery and signalling only are accurate when they can rapidly reflect all new information faced by its market agents. Thereby, when a given market is efficient, it allows for allocative efficiency, reducing inefficiencies both in decision-making process and in informational costs. On the other hand, when markets are said not to be efficient, agribusinesses\' agents can make mistaken production, marketing and storage decisions, once such decisions are due to incomplete information contained in past prices. In this context, the main purpose of this study is to analyze the efficiency in future markets of commodities. In order to achieve its final goal, the study has been structured in three essays. In the first essay, the random walk hypothesis has been tested for agricultural future contracts from Brazilian Securities, Commodities and Futures Exchange (BMF&BOVESPA). Refusing the hypothesis for a given commodity implies some degree of predictability, therefore inconsistent even with a weak notion of efficiency. These tests were carried out using serial correlations and variance ratios. The results show the presence of random walks in coffee and soybean future markets, and contrary evidences (absence of random walks) in live cattle, corn and ethanol future markets. In the second essay, it has been analyzed the efficiency and the presence of clusters in the soybean complex future contracts (soybean, soybean meal and soybean oil) traded in the following future markets: Argentina (MTB), Brazil (BVMF), China (DCE), India (NCD), Japan (TKT), US (CBT) and South-Africa (SAF). Based on the metrics obtained by Euclidian distances of variance ratios, similar dependencies have been found for all markets, which suggest informational efficiency spreading. Agents, therefore, shall maintain perceptions over several international markets, given the interdependence found for prices in distinct future markets. In the third one, the adaptive market hypothesis has been tested for agricultural future markets in Brazil. Applying more recent approaches to Nonlinearity and Variance Ratio tests, high rejections to martingale difference hypothesis took place in agricultural markets which governmental interference is highly persistent, i.e., corn and ethanol. In coffee, live cattle and soybeans markets, weaker rejections to the martingale hypothesis hint higher informational efficiency. These evidences, consistent with the adaptive market hypothesis, justify dynamic hedge operations, as well as an active management of investment portfolios in such markets.

This literature review explores human mirror neurons from several angles. First it retells mirror neuron history, from the initial discovery in the macaque monkey research through to the experiments determining if there is a human brain homologue. Then the merits of two opposing evolutionary views – mirror neurons as an adaptation or an association, here referring to an adaptation’s byproduct – are discussed. Lastly the autistic mirror neuron dysfunction hypothesis – stating that a faulty mirror neuron system is at the basis of autistic behavioral patterns – is examined for its validity but ultimately found lacking and in need of further development.

>Magister Scientiae - MSc / This research undertakes to investigate both long-term and short-term investor overreaction on the JSE Limited (JSE) over the period from 1 January 2002 to 31 December 2009. The period covers the restructuring and reform of the JSE in the early 2000s to the end of global financial market crisis in late 2008/2009, which can be regarded as a complete economic cycle. The performances of the winner and loser portfolios are evaluated by assessing their cumulative abnormal returns (CAR) over a 24-month holding period. The test results show no evidence of mean reversion for winner and loser portfolios formed based on prior returns of 12 months or less. However, test results show evidence of significant mean reversion for the winner and loser portfolios constructed based on their prior 24 months and 36 months returns. In addition, the study reveals that the mean reversion is more significant for longer-formation-period portfolios as well as for longer holding periods. The examination of the cumulative loser-winner spreads obtained from the contrarian portfolios based on the constituents’ prior 24 month and 36 month returns indicates that the contrarian returns increase for portfolios formed between 2004 and 2006, and declines thereafter towards the end of the examination period. The deterioration of contrarian returns coincides with the subprime mortgage crisis in 2007 and the subsequent global financial crisis in 2008. This evidence suggests that the degree of mean reversion on the JSE is positively correlated to the South African business cycle.

Pour expliquer les faibles taux d'endémisme rencontrés chez les mousses en Macaronésie, deux hypothèses ont été successivement testées et invalidées au cours de mon doctorat chez deux genres de mousses d'occurrence macaronésienne, phylogénétiquement proches, Hedenasiastrum et Rhynchostegiella. Une première hypothèse suggérait que les mousses sont des organismes à faible potentiel évolutif peu enclins à former des espèces endémiques. Si une apparente stase morphologique de plus de 40 millions d'années a été reconstruite chez Hedenasiastrum, genre monotypique endémique de Madère, le grand nombre de convergences phénotypiques et les taux très élevés de diversification insulaire dans le genre Rhynchostegiella, infirment très fortement cette hypothèse. Ces études tendent ainsi à mettre en valeur la nature hyper adaptable des mousses et la diversité des processus évolutifs pouvant se mettre en place pour des espèces proches, dans une même région biogéographique. Une seconde hypothèse évoquait des flux de gènes intenses entre continents et îles, bloquant la spéciation insulaire ; hypothèse à son tour réfutée par le grand nombre d'évènements de spéciation in situ dans les îles, révélé par nos analyses de reconstruction d'aires ancestrales. Ce travail dévoile au final que la généralisation des colonisations inverses des îles vers le continent, pourrait être un des facteurs majeur expliquant les faibles taux d'endémisme macaronésiens chez les mousses. Plus que des puits de diversité, les îles seraient ainsi une source importante de biodiversité pour le continent chez les organismes capables de dispersion longue distance. / To explain the low rates of endemism encountered in Macaronesian mosses, two hypotheses have been successfully tested and invalidated during my PhD in two genera of mosses of the subfamily Helicodontioideae occurring in Macaronesia Islands, respectively Hedenasiastrum and Rhynchostegiella. The first hypothesis suggested that mosses are low evolutionary potential organisms, reluctant to form endemic species; if an apparent morphological stasis over 40 million years was reconstructed in Hedenasiastrum, a monotypic genus endemic of Madeira, the large number of phenotypic convergences and high rates of insular diversification in the genus Rhynchostegiella, strongly refute this hypothesis. Thereby these studies tend to emphasize the hyper-adaptability of mosses and the diversity of evolutionary processes that can occur in closely related species in the same biogeographic region. The second hypothesis evoked too intense gene flow between mainland and islands, preventing speciation on islands; a hypothesis invalidated by the high number of in situ event of speciation on islands revealed by our analysis of ancestral area reconstruction. Finally this work reveals generalized reverse colonization from islands to mainland after in situ speciation, as one of major factor responsible for low rates of endemism in the Macaronesian mosses. Islands may thus appear for organisms with high dispersal ability as inexhaustible sources of diversity.

Much has been written, by academics, about the impact sponsorship announcements have on the share price performance of sponsoring firms. The objective of this study was to investigate if this phenomenon was true for JSE listed companies with particular focus on three announcement categories i.e. (i) new, (ii) renew and (iii) termination. The Efficient Market Hypothesis as an aspect of Investment Finance behaviour was explored to understand why sponsorship announcements would or would not have an impact on the share price performance. For this study, descriptive research was done with a causal design as the study tested the relationship between two or more variables. The study analysed 118 sponsorship announcements made by 19 JSE listed companies over a period of eleven years and five months. The study then assessed the share price performance for the period 120 days prior to and 120 days after the announcement date. The share price holding periods were adjusted for that of the average Financial Services (J212) Index, the Industrial (J212) Index and the Resources (J258) Index respectively to ascertain whether the returns were abnormal or not. The results have shown that there were no evidence that the announcement of a (i) new, (ii) renewed or (iii) terminated sponsorship do have a significant impact on the performance of share prices for JSE listed companies. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

This study examines the determinants of private placement discounts and announcement effects on the Stockholm Stock Exchange between 2014 and 2022. The results show that private placement announcement effects are significantly positive, reinforcing the empirical support for the monitoring hypothesis and information hypotheses. Positive announcement effects reflect signals of certification from private equity investors that the firm is undervalued. Regression analysis suggests that information costs and some firm characteristics are important determinants for discounts on private placements. Private equity investors will demand larger discounts when information asymmetry is high, and cash flow restraints are more severe. Foreign investors require significantly smaller discounts on private placements, possibly implying that they commonly assume a passive rather than active role as shareholders. Firms’ stated motivations for private placements and the agreed discounts are significantly related to stock market reactions. Specifically, motivations relating to an investment in a new project or an acquisition are associated with significantly more positive announcement effects.

Syftet med den här uppsatsen har varit att undersöka fyra gymnasieelevers erfarenheter av språkundervisning i moderna språk.Uppsatsens frågeställningar är:• Hur beskriver eleverna sin språkundervisning?• Vilka strategier använder sig eleverna av vid språkinlärningen?• Vilka teorier kring lärande går att observera i elevernas undervisning? Underlaget till uppsatsen har varit fyra gymnasieelevers utsagor om språkinlärning i form av kvalitativa intervjuer. Elevernas utsagor har analyserats med hjälp av olika teorier med anknytning till språkinlärning. Slutsatsen är att denna språkundervisning lägger tonvikten på den sociala interaktionen, vilket speglar den forskning som har gjorts de senaste 30 åren. Det visade sig även att det fortfarande finns spår av äldre metoder i dagens undervisning, och att det är problematiskt att hitta en balans mellan lärarcentrerad och elevorienterad undervisning.

The purpose of this qualitative study is to compare five teachers’ beliefs about their students’ learning of vocabulary and compare that with current theories and recommended practices in the field. The method for collecting data was semi-structured interviews with teachers who teach English in both lower secondary and upper secondary schools in Sweden. The data from these interviews were then analyzed by way of thematic analysis. The results were then compared with previous research in the field of vocabulary learning drawing on studies and works of researchers such as Stuart Webb and Paul Nation among others. The results reveal a lot of similarities with the latest research on vocabulary learning. The findings of this study also indicate some differences between teacher beliefs and research. Apart from research done in the field of vocabulary learning this study has also taken the proven experience of the teachers into account. Since this study is of a qualitative kind, these results cannot be generalized in regard to Swedish teachers of English as a group but rather what some of them portray when talking on the topic of vocabulary.