Home About us Contact
|
Home About us Contact | ||
|
|
||
Global Importance (global + importance)
Selected AbstractsTHE MUTATION MATRIX AND THE EVOLUTION OF EVOLVABILITYEVOLUTION, Issue 4 2007Adam G. Jones Evolvability is a key characteristic of any evolving system, and the concept of evolvability serves as a unifying theme in a wide range of disciplines related to evolutionary theory. The field of quantitative genetics provides a framework for the exploration of evolvability with the promise to produce insights of global importance. With respect to the quantitative genetics of biological systems, the parameters most relevant to evolvability are the G -matrix, which describes the standing additive genetic variances and covariances for a suite of traits, and the M -matrix, which describes the effects of new mutations on genetic variances and covariances. A population's immediate response to selection is governed by the G -matrix. However, evolvability is also concerned with the ability of mutational processes to produce adaptive variants, and consequently the M -matrix is a crucial quantitative genetic parameter. Here, we explore the evolution of evolvability by using analytical theory and simulation-based models to examine the evolution of the mutational correlation, r,, the key parameter determining the nature of genetic constraints imposed by M. The model uses a diploid, sexually reproducing population of finite size experiencing stabilizing selection on a two-trait phenotype. We assume that the mutational correlation is a third quantitative trait determined by multiple additive loci. An individual's value of the mutational correlation trait determines the correlation between pleiotropic effects of new alleles when they arise in that individual. Our results show that the mutational correlation, despite the fact that it is not involved directly in the specification of an individual's fitness, does evolve in response to selection on the bivariate phenotype. The mutational variance exhibits a weak tendency to evolve to produce alignment of the M -matrix with the adaptive landscape, but is prone to erratic fluctuations as a consequence of genetic drift. The interpretation of this result is that the evolvability of the population is capable of a response to selection, and whether this response results in an increase or decrease in evolvability depends on the way in which the bivariate phenotypic optimum is expected to move. Interestingly, both analytical and simulation results show that the mutational correlation experiences disruptive selection, with local fitness maxima at ,1 and +1. Genetic drift counteracts the tendency for the mutational correlation to persist at these extreme values, however. Our results also show that an evolving M -matrix tends to increase stability of the G -matrix under most circumstances. Previous studies of G -matrix stability, which assume nonevolving M -matrices, consequently may overestimate the level of instability of G relative to what might be expected in natural systems. Overall, our results indicate that evolvability can evolve in natural systems in a way that tends to result in alignment of the G -matrix, the M -matrix, and the adaptive landscape, and that such evolution tends to stabilize the G -matrix over evolutionary time. [source] The American national interest and global public goodsINTERNATIONAL AFFAIRS, Issue 2 2002Joseph S. Nye Jr Since the end of the Cold War, Americans have been divided over how to be involved with the rest of the world. In the wake of the 11 September terrorist attacks, the debate between those who favour a unilateral foreign policy and those who advocate a multilateral approach has been brought to the fore in American politics and the media. In this article, Joseph Nye proposes a conception of the American national interest grounded in multilateralism. He argues that, although the United States remains the world's leading power, it cannot act alone to solve global problems such as transnational terrorism, the proliferation of weapons of mass destruction and global warming. Although the United States is the only country in a position to take the lead in protecting ,global public goods', such as an open international economic system and international stability, it will maintain its current predominance only if it works to establish international consensus on issues of global importance. [source] Can the Mediterranean diet prevent prostate cancer?MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2009Catherine Itsiopoulos Abstract Prostate cancer is the second most common cancer in men worldwide. Despite the global importance of this cancer, until recently little was known about risk factors apart from the well-established factors: age, family history and country of birth. The large worldwide variation in prostate cancer risk and increased risk in migrants moving from low to high risk countries provides strong support for modifiable environmental factors. We have based our review on the findings of a systematic review undertaken by an expert panel on behalf of the World Cancer Research Fund and the American Institute for Cancer Research, and new data since then, linking identified foods and nutrients with prostate cancer. Evidence indicates that foods containing lycopene, as well as selenium and foods containing it, probably protect against prostate cancer, and excess consumption of foods or supplements containing calcium are a probable cause of this cancer. The expert panel also concluded that it is unlikely that ,-carotene (whether from foods or supplements) has a substantial effect on the risk of this cancer. A recent review on environmental factors in human prostate cancer also found that there were protective effects of vitamin E, pulses, soy foods and high plasma 1,25-dihydroxyvitamin D levels. The Mediterranean diet is abundant in foods that may protect against prostate cancer and is associated with longevity and reduced cardiovascular and cancer mortality. Compared with many Western countries Greece has lower prostate cancer mortality and Greek migrant men in Australia have retained their low risk for prostate cancer. Consumption of a traditional Mediterranean diet, rich in bioactive nutrients, may confer protection to Greek migrant men, and this dietary pattern offers a palatable alternative for prevention of this disease. [source] cDNA-AFLP reveals genes differentially expressed during the hypersensitive response of cassavaMOLECULAR PLANT PATHOLOGY, Issue 2 2005BENJAMIN P. KEMP SUMMARY The tropical staple cassava is subject to several major diseases, such as cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis. Disease-resistant genotypes afford the only practical solution, yet despite the global importance of this crop, little is known about its defence mechanisms. cDNA-AFLP was used to isolate cassava genes differentially expressed during the hypersensitive reaction (HR) of leaves in response to an incompatible Pseudomonas syringae pathovar. Seventy-eight transcript-derived fragments (TDFs) showing differential expression (c. 75% up-regulated, 25% down-regulated) were identified. Many encoded putative homologues of known defence-related genes involved in signalling (e.g. calcium transport and binding, ACC oxidases and a WRKY transcription factor), cell wall strengthening (e.g. cinnamoyl coenzyme A reductase and peroxidase), programmed cell death (e.g. proteases, 26S proteosome), antimicrobial activity (e.g. proteases and ,-1,3-glucanases) and the production of antimicrobial compounds (e.g. DAHP synthase and cytochrome P450s). Full-length cDNAs including a probable matrix metalloprotease and a WRKY transcription factor were isolated from six TDFs. RT-PCR or Northern blot analysis showed HR-induced TDFs were maximally expressed at 24 h, although some were produced by 6 h; some were induced, albeit more slowly, in response to wounding. This work begins to reveal potential defence-related genes of this understudied, major crop. [source] Unravelling response-specificity in Ca2+ signalling pathways in plant cellsNEW PHYTOLOGIST, Issue 1 2001Jason J. Rudd Summary Considerable advances have been made, both in the technologies available to study changes in intracellular cytosolic free Ca2+ ([Ca2+]i), and in our understanding of Ca2+ signalling cascades in plant cells, but how specificity can be generated from such a ubiquitous component as Ca2+ is questionable. Recently the concept of ,Ca2+ signatures' has been formulated; tight control of the temporal and spatial characteristics of alterations in [Ca2+]i signals is thought to be responsible, at least in part, for the specificity of the response. However, the way in which Ca2+ signatures are decoded, which depends on the nature and location of the targets of the Ca2+ signals, has received little attention. In a few key systems, progress is being made on how diverse Ca2+ signatures might be transduced within cells in response to specific signals. Valuable pieces of the signal-specificity puzzle are being put together and this is illustrated here using some key examples; these emphasize the global importance of Ca2+ -mediated signal-transduction cascades in the responses of plants to a wide diversity of extracellular signals. However, the way in which signal specificity is encoded and transduced is still far from clear. [source] FRONTIER EFFICIENCY MEASUREMENT IN DEPOSIT-TAKING FINANCIAL MUTUALS: A REVIEW OF TECHNIQUES, APPLICATIONS, AND FUTURE RESEARCH DIRECTIONSANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 1 2010Andrew C. Worthington ABSTRACT,:,Despite the global importance of mutuals in financial services, and the universal need to measure and improve organizational efficiency in all deposit-taking institutions, it is only relatively recently that the most advanced econometric and mathematical programming frontier techniques have been applied. This paper provides a synoptic survey of the comparatively few empirical analyses of frontier efficiency measurement in deposit-taking financial mutuals, comprising savings and loans, building societies and credit unions in Australia, the UK, and the USA. Both estimation and measurement techniques and the determinants of efficiency are examined. Particular focus is placed on how the results of these studies may help inform regulatory policy and managerial behaviour. [source] Molecular interactions between Plasmodium and its insect vectorsCELLULAR MICROBIOLOGY, Issue 11 2002R. E. Sinden Summary Our understanding of the intricate interactions between the malarial parasite and the mosquito vector is complicated both by the number and diversity of parasite and vector species, and by the experimental inaccessibility of phenomena under investigation. Steady developments in techniques to study the parasite in the mosquito have recently been augmented by methods to culture in their entirety the sporogonic stages of some parasite species. These, together with the new saturation technologies, and genetic transformation of both parasite and vector will permit penetrating studies into an exciting and largely unknown area of parasite,host interactions, an understanding of which must result in the development of new intervention strategies. This microreview highlights key areas of current basic molecular interest, and identifies numerous lacunae in our knowledge that must be filled if we are to make rational decisions for future control strategies. It will conclude by trying to explain why in the opinion of this reviewer understanding malaria,mosquito interactions may be critical to our future attempts to limit a disease of growing global importance. [source] Chemieindustrie: Herausforderungen und Antworten,CHEMIE-INGENIEUR-TECHNIK (CIT), Issue 1-2 2004R. Staudigl Dr. Abstract Die Chemie ist heute einer der umsatzstärksten Wirtschaftszweige weltweit und auf allen Kontinenten vertreten. Die Unternehmenslandschaft in der Chemie hat sich seit dem Zweiten Weltkrieg völlig verändert. Aus diversifizierten Unternehmen wurden in den meisten Fällen Spezialisten, die auf wenige Geschäftsbereiche konzentriert sind und dort optimale Leistungen bringen können, dafür aber Marktschwankungen stärker ausgesetzt sind. Zukünftig ist abzusehen, dass der europäische Chemiemarkt global weiter an Gewicht verlieren wird. Dem kann nur durch höheres Wirtschaftswachstum und verstärkte Innovationsbemühungen in Europa entgegengewirkt werden. Voraussetzung ist jedoch, dass die Chemieindustrie nicht durch ständig zunehmende Belastungen wie unn,tige Umweltauflagen und steigende Energiepreise weiter in Rückstand gerät und als Konsequenz davon wegen mangelnder Profitabilität an Innovationskraft und Wettbewerbsfähigkeit verliert. The Chemical Industry: Challenges and Answers The chemical industry today is a branch of economy with one of the highest turnover worldwide and it is represented on all continents. Since World War II the structure of chemical companies has changed completely. Many companies which used to be active in different branches have become more specialized in order to optimize their economical performance. On the other hand specialization increases their dependence on market fluctuations. In the future, the European chemical industry will loose global importance. This development can only be prevented by increasing economical growth and more intense innovation efforts. A precondition for this is that the chemical industry will not be restricted by constantly increasing charges, e.g., unnecessary environmental regulations, and increasing energy costs. These restrictions would result in a lack of profitability and thus to limited innovation power and competitiveness. [source] | ||||||||||