9,296 research outputs found

    Taxation and the Stock Market Valuation of Capital Gains and Dividends: Theory and Empirical Results (Rev)

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    Dividends seem to be more heavily taxed than capital gains. Why then do corporations pay dividends rather than repurchasing shares or retaining earnings? Either corporations are not acting in the interests of shareholders, or else shareholders desire dividends sufficiently for nontax reasons to offset the tax effect. In this paper, we measure the relative valuation of dividends and capital gains in the stock market, using a variant of the capital asset pricing model. We find that dividends are not valued differently systematically from capital gains. This finding is consistent with share price maximization by firms but inconsistent with the fact that most shareholders pay a heavier tax on dividends. We also show that the relative value of dividends provides an indirect measure of a marginal Tobin's q. The measured value of dividends relative to capital gains tends to be higher during prosperous periods, as is consistent with this interpretation. We hope that this time series on a marginal Tobin's q will prove to be useful in forecasting the rate of investment.

    Evaluating Streptococcus mutans strain dependent characteristics in a polymicrobial biofilm community

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    Aim: The purpose of this study was to investigate strain dependent differences of the cariogenic biofilm forming Streptococcus mutans within both simple and complex communities. Methods: A mono-species containing representative S. mutans clinical isolates (caries and non-caries), and a multispecies in vitro caries biofilm model containing Lactobacillus casei, Veillonella dispar, Fusobacterium nucleatum and Actinomyces naeslundii, and either of two representative S. mutans clinical isolates (caries and non-caries), was developed as a comparison model. Compositional analysis of total and live bacteria within biofilms, and transcriptional analysis of biofilm associated virulence factors were evaluated by live/dead PCR and quantitative PCR, respectively. Scanning electron microscopy (SEM) was used to analyze the architecture of biofilm. One-way analysis of variance and t-tests were used to investigate significant differences between independent groups of data. Results: Within a mono-species biofilm, different S. mutans strains responded similarly to one another during biofilm formation in different carbohydrate sources, with sucrose showing the highest levels of biofilm biomass and galactose showing the lowest. Within the polymicrobial biofilm system, compositional analysis of the bacteria within the biofilm showed that S. mutans derived from a caries-free patient was preferentially composed of both total and viable L. casei, whereas S. mutans derived from a caries patient was dominated by both total and viable S. mutans (p < 0.001). Normalized gene expression analysis of srtA, gtfB, ftf, spaP, gbpB, and luxS, showed a general upregulation within the S. mutans dominant biofilm. Conclusion: We were able to demonstrate that individual strains derived from different patients exhibited altered biofilm characteristics, which were not obvious within a simple mono-species biofilm model. Influencing the environmental conditions changed the composition and functionality S. mutans within the polymicrobial biofilm. The biofilm model described herein provides a novel and reproducible method of assessing the impact on the biofilm microbiome upon different environmental influences

    The application of phenotypic microarray analysis to anti-fungal drug development

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    Candida albicans metabolic activity in the presence and absence of acetylcholine was measured using phenotypic microarray analysis. Acetylcholine inhibited C. albicans biofilm formation by slowing metabolism independent of biofilm forming capabilities. Phenotypic microarray analysis can therefore be used for screening compound libraries for novel anti-fungal drugs and measuring antifungal resistance

    The World Bank and Its Critics: the Case of Sub-Saharan Africa

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    In 1981, as Sub-Saharan Africa continued in its downward spiral of economic demise, the World Bank issued a major study on the causes of Africa's economic woes and potential short-term steps to alleviate them. The World Bank's Accelerated Development in Sub-Saharan Africa: An Agenda for Action. In this paper, the authors dissect a number of the major controversies engendered by the World Bank Report, by presenting and evaluating the differences between the authors of the Report and critics of the Report.Center for Research on Economic Development, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100718/1/ECON187.pd

    People's Democratic Republic of Ralandia Two Case Studies

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    The following case studies were designed to promote class discussion on economic policy in developing countries. They are problem solving cases, self-contained, and do not require any additional data. There are three components: Ralandia (A), (B), and (C). Ralandai is a fictitious country located on the southeastern coast of Africa. Ralandia (A) gives an overview of the country, and is not in itself a case study. Ralandia (A) together with Ralandia (B) make up the case on Agricultural Policy; and Ralandia (A) together with Ralandia (C) make up the case on Macroeconomic Policy. In approaching the cases, the reader should keep in mind the following questions: what are the problems that exist; what are the factors which affect why certain policies success and others fail; what is the effect of politics on economic policy; and what are the economic implications of political acts?Center for Research on Economic Development, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100964/1/ECON408.pd

    Aspergillus fumigatus enhances elastase production in pseudomonas aeruginosaco-cultures

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    In the cystic fibrosis (CF) lung the presence of bacteria and fungi in the airways promotes an inflammatory response causing progressive lung damage, ultimately leading to high rates of morbidity and mortality. We hypothesized that polymicrobial interactions play an important role in promoting airway pathogenesis. We therefore examined the interplay between the most commonly isolated bacterial CF pathogen, Pseudomonas aeruginosa, and the most prevalent filamentous fungi, Aspergillus fumigatus, to test this. Co-culture experiments showed that in the presence of A. fumigatus the production of P. aeruginosa elastase was enhanced. This was confirmed by the presence of zones of clearance on Elastin-Congo Red (ECR) agar, which was identified as elastase by mass spectrometry. When P. aeruginosa were grown in a co-culture model with mature A. fumigatus biofilms, 60% of isolates produced significantly more elastase in the presence of the filamentous fungi than in its absence (P < .05). The expression of lasB also increased when P. aeruginosa isolates PA01 and PA14 were grown in co-culture with A. fumigatus. Supernatants from co-culture experiments were also significantly toxic to a human lung epithelial cell line (19–38% cell cytotoxicity) in comparison to supernatants from P. aeruginosa only cultures (P < .0001). Here we report that P. aeruginosa cytotoxic elastase is enhanced in the presence of the filamentous fungi A. fumigatus, suggesting that this may have a role to play in the damaging pathology associated with the lung tissue in this disease. This indicates that patients who have a co-colonisation with these two organisms may have a poorer prognosis

    Science-based restoration monitoring of coastal habitats, Volume Two: Tools for monitoring coastal habitats

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    Healthy coastal habitats are not only important ecologically; they also support healthy coastal communities and improve the quality of people’s lives. Despite their many benefits and values, coastal habitats have been systematically modified, degraded, and destroyed throughout the United States and its protectorates beginning with European colonization in the 1600’s (Dahl 1990). As a result, many coastal habitats around the United States are in desperate need of restoration. The monitoring of restoration projects, the focus of this document, is necessary to ensure that restoration efforts are successful, to further the science, and to increase the efficiency of future restoration efforts

    Cylindrical Shell based Phase Transforming Cellular Materials: Designing a Recoverable Energy Dissipating Material

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    Energy dissipating materials are used in a variety of impact events to protect more important parts of a system; one example of this is a football player’s helmet protecting a brain. A major drawback to classic energy dissipating materials however is that they dissipate energy through plastic deformation, meaning that after a single use, permanent deformations will prevent the material from being reusable to the same capacity as initially. We have designed a 1D cellular material in which geometric phase transformations in cylindrical shell elements are the primary energy dissipating mechanism, allowing for recoverability after use while keeping high energy dissipation functionality. Finite element analysis was used to evaluate cylindrical shell ligaments of differing lengths and angle of inclination, after which key parameter combinations were identified. Physical samples were manufactured and tested in loading and unloading cycles. It was found through simulations that ligaments with high length and high angle of inclination gave the greatest amount of energy dissipation. Mechanical tests have shown key similarities in deformation modes with the simulations, and verified that there is significant energy dissipation due to phase transformations. This concept could improve design in many fields, such as car bumper design and earthquake damage control, by adding recoverable elements to structural design. This would mean that energy dissipation mechanisms could be implemented in places not utilized before, as well as reducing the recovery effort post impact

    The anti-adhesive effect of curcumin on Candida albicans biofilms on denture materials

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    The use of natural compounds as an alternative source of antimicrobials has become a necessity given the growing concern over global antimicrobial resistance. Polyphenols, found in various edible plants, offers one potential solution to this. We aimed to investigate the possibility of using curcumin within the context of oral health as a way of inhibiting and preventing the harmful development of Candida albicans biofilms. We undertook a series of adsorption experiments with varying concentrations of curcumin, showing that 50 ug/ml could prevent adhesion. This effect could be further synergised by the curcumin pretreatment of yeast cells to obtain significantly greater inhibition (>90, p<0.001). Investigation of the biological impact of curcumin showed that it preferentially affected immature morphological forms (yeast and germlings), and actively promoted aggregation of the cells. Transcriptional analyses showed that key adhesins were down-regulated (ALS1 and ALS3), whereas aggregation related genes (ALS5 and AAF1) were up-regulated. Collectively, these data demonstrated that curcumin elicits anti-adhesive effects and that induces transcription of genes integrally involved in the processes related to biofilm formation. Curcumin and associated polyphenols therefore have the capacity to be developed for use in oral healthcare to augment existing preventative strategies for candidal biofilms on the denture surface
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