Chemotherapeutics are the most effective treatment for metastatic tumours. However, the ability of cancer cells to become simultaneously resistant to different drugs--a trait known as multidrug resistance--remains a significant impediment to successful chemotherapy. Three decades of multidrug-resistance research have identified a myriad of ways in which cancer cells can elude chemotherapy, and it has become apparent that resistance exists against every effective drug, even our newest agents. Therefore, the ability to predict and circumvent drug resistance is likely to improve chemotherapy.

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Multidrug resistance in cancer: role of ATP–dependent transporters

This paper introduces a three-item "Cognitive Reflection Test" (CRT) as a simple measure of one type of cognitive ability—the ability or disposition to reflect on a question and resist reporting the first response that comes to mind. The author will show that CRT scores are predictive of the types of choices that feature prominently in tests of decision-making theories, like expected utility theory and prospect theory. Indeed, the relation is sometimes so strong that the preferences themselves effectively function as expressions of cognitive ability—an empirical fact begging for a theoretical explanation. The author examines the relation between CRT scores and two important decision-making characteristics: time preference and risk preference. The CRT scores are then compared with other measures of cognitive ability or cognitive "style." The CRT scores exhibit considerable difference between men and women and the article explores how this relates to sex differences in time and risk preferences. The final section addresses the interpretation of correlations between cognitive abilities and decision-making characteristics.

/pdf/cognitive-reflection-and-decision-making-u372g0yreb.pdf

Cognitive Reflection and Decision Making

Effective treatment of metastatic cancers usually requires the use of toxic chemotherapy. In most cases, multiple drugs are used, as resistance to single agents occurs almost universally. For this reason, elucidation of mechanisms that confer simultaneous resistance to different drugs with different targets and chemical structures - multidrug resistance - has been a major goal of cancer biologists during the past 35 years. Here, we review the most common of these mechanisms, one that relies on drug efflux from cancer cells mediated by ATP-binding cassette (ABC) transporters. We describe various approaches to combating multidrug-resistant cancer, including the development of drugs that engage, evade or exploit efflux by ABC transporters.

Targeting multidrug resistance in cancer

Intrinsically unstructured proteins: re-assessing the protein structure-function paradigm.

Stem cells from bone marrow, skeletal muscle and possibly other tissues can be identified by the 'side-population' (SP) phenotype. Although it has been assumed that expression of ABC transporters is responsible for this phenotype, the specific molecules involved have not been defined. Here we show that expression of the Bcrp1 (also known as Abcg2 murine/ABCG2 human) gene is a conserved feature of stem cells from a wide variety of sources. Bcrp1 mRNA was expressed at high levels in primitive murine hematopoietic stem cells, and was sharply downregulated with differentiation. Enforced expression of the ABCG2 cDNA directly conferred the SP phenotype to bone-marrow cells and caused a reduction in maturing progeny both in vitro and in transplantation-based assays. These results show that expression of the Bcrp1/ABCG2 gene is an important determinant of the SP phenotype, and that it might serve as a marker for stem cells from various sources.

The ABC transporter Bcrp1/ABCG2 is expressed in a wide variety of stem cells and is a molecular determinant of the side-population phenotype

This study shows that people's propensity to gamble and their investment decisions are correlated. At an aggregate level, individual investors prefer stocks with lottery features, and like lottery demand, the demand for lottery-type stocks increases during economic downturns. In the cross-section, socioeconomic factors that induce greater expenditure in lotteries are associated with greater investment in lottery-type stocks. Further, these investment levels are higher in regions with favorable lottery environments. Because lottery-type stocks under-perform, gambling-related under-performance is greater among low-income investors who excessively overweight lottery-type stocks. Collectively, these results indicate that state lotteries and lottery-type stocks attract very similar socioeconomic clienteles.

https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID1263476_code56396.pdf?abstractid=686022&mirid=5

Who Gambles in the Stock Market

Using a database of more than 1.85 million transactions made by retail investors over a six-year period (1991-96), we show that these trades are systematically correlated − i.e., individuals buy (or sell) stocks in concert. Moreover, as predicted by noise trader models, we find that systematic retail trading explains return comovements for stocks with high retail concentration (i.e., small-cap, value, lower institutional ownership, and lower-priced stocks), especially if these stocks are also costly to arbitrage. Macro-economic news and analyst earnings forecast revisions do not explain these results. Collectively, our findings support a role for investor sentiment in returns formation.

https://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID756925_code56396.pdf?abstractid=502843&mirid=4

Retail Investor Sentiment and Return Comovements

This study shows that the propensity to gamble and investment decisions are correlated. At the aggregate level, individual investors prefer stocks with lottery features, and like lottery demand, the demand for lottery-type stocks increases during economic downturns. In the cross-section, socioeconomic factors that induce greater expenditure in lotteries are associated with greater investment in lottery-type stocks. Further, lottery investment levels are higher in regions with favorable lottery environments. Because lottery-type stocks underperform, gambling-related underperformance is greater among low-income investors who excessively overweight lottery-type stocks. These results indicate that state lotteries and lottery-type stocks attract very similar socioeconomic clienteles.

/pdf/who-gambles-in-the-stock-market-2gbcvutsg0.pdf

Using a database of more than 1.85 million retail investor transactions over 1991–1996, we show that these trades are systematically correlated—that is, individuals buy (or sell) stocks in concert. Moreover, consistent with noise trader models, we find that systematic retail trading explains return comovements for stocks with high retail concentration (i.e., small-cap, value, lower institutional ownership, and lower-priced stocks), especially if these stocks are also costly to arbitrage. Macroeconomic news and analyst earnings forecast revisions do not explain these results. Collectively, our findings support a role for investor sentiment in the formation of returns.

This study shows that U.S. individual investors hold under-diversified portfolios, where the level of under-diversification is greater among younger, low-income, less-educated, and less-sophisticated investors. The level of under-diversification is also correlated with investment choices that are consistent with over-confidence, trend-following behavior, and local bias. Furthermore, investors who over-weight stocks with higher volatility and higher skewness are less diversified. In contrast, there is little evidence that portfolio size or transaction costs constrains diversification. Under-diversification is costly to most investors, but a small subset of investors under-diversify because of superior information. Copyright 2008, Oxford University Press.

/pdf/equity-portfolio-diversification-3ri8bfv3j8.pdf

Alok Kumar

Papers

Who Gambles in the Stock Market

Retail Investor Sentiment and Return Comovements

Who Gambles in the Stock Market

Retail Investor Sentiment and Return Comovements

Equity Portfolio Diversification