306 research outputs found

    New directions in island biogeography

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    Aim: Much of our current understanding of ecological and evolutionary processes comes from island research. With the increasing availability of data on distributions and phylogenetic relationships and new analytical approaches to understanding the processes that shape species distributions and interactions, a re-evaluation of this ever-interesting topic is timely. Location: Islands globally. Methods: We start by arguing that the reasons why island research has achieved so much in the past also apply to the future. We then critically assess the current state of island biogeography, focusing on recent changes in emphasis, including research featured in this special issue of Global Ecology and Biogeography. Finally, we suggest promising themes for the future. We cover both ecological and evolutionary topics, although the greater emphasis on island ecology reflects our own backgrounds and interests. Results: Much ecological theory has been directly or indirectly influenced by research on island biotas. Currently, island biogeography is renascent, with research focusing on, among other things, patterns and processes underlying species interaction networks, species coexistence and the assembly of island communities through ecological and evolutionary time. Continuing island research should provide additional insight into biological invasions and other impacts of human activities, functional diversity and ecosystem functioning, extinction and diversification, species pools and more. Deeper understanding of the similarities and differences between island and mainland systems will aid transferability of island theory to continental regions. Main conclusions: As research in biogeography and related fields expands in new directions, islands continue to provide opportunities for developing insights, both as natural laboratories for ecology and evolution and because of the exceptions islands often present to the usual ‘rules’ of ecology. New data collection initiatives are needed on islands world-wide and should be directed towards filling gaps in our knowledge of within-island distributions of species, as well as the functional traits and phylogenetic relationships of island species

    Detailed electronic structure studies on superconducting MgB2_2 and related compounds

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    In order to understand the unexpected superconducting behavior of MgB2_2 compound we have made electronic structure calculations for MgB2_2 and closely related systems. Our calculated Debye temperature from the elastic properties indicate that the average phonon frequency is very large in MgB2_2 compared with other superconducting intermetallics and the exceptionally high TcT_c in this material can be explained through BCS mechanism only if phonon softening occurs or the phonon modes are highly anisotropic. We identified a doubly-degenerate quasi-two dimensional key-energy band in the vicinity of EFE_{F} along Γ\Gamma-A direction of BZ which play an important role in deciding the superconducting behavior of this material. Based on this result, we have searched for similar kinds of electronic feature in a series of isoelectronic compounds such as BeB2_2, CaB2_2, SrB2_2, LiBC and MgB2_2C2_2 and found that MgB2_2C2_2 is one potential material from the superconductivity point of view. There are contradictory experimental results regarding the anisotropy in the elastic properties of MgB2_2 ranging from isotropic, moderately anisotropic to highly anisotropic. In order to settle this issue we have calculated the single crystal elastic constants for MgB2_2 by the accurate full-potential method and derived the directional dependent linear compressibility, Young's modulus, shear modulus and relevant elastic properties. We have observed large anisotropy in the elastic properties. Our calculated polarized optical dielectric tensor shows highly anisotropic behavior even though it possesses isotropic transport property. MgB2_2 possesses a mixed bonding character and this has been verified from density of states, charge density and crystal orbital Hamiltonian population analyses

    Improvements in the determination of ISS Ca II K parameters

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    Measurements of the ionized Ca II K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a ground-based proxy to model the solar ultraviolet flux variation that may influence the Earth's climate. Full disk images of the Sun in Ca II K have been available from various observatories for more than 100 years and latter synoptic Sun-as-a-star observations in Ca II K began in the early 1970s. One of these instruments, the Integrated Sunlight Spectrometer (ISS) has been in operation at Kitt Peak (Arizona) since late 2006. The ISS takes daily observations of solar spectra in nine spectra bands, including the Ca II K and H line s. We describe recent improvements in data reduction of Ca II K observations, and present time variations of nine parameters derived from the profile of this spectral line

    Genome-wide association analyses identify 13 new susceptibility loci for generalized vitiligo

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    We previously reported a genome-wide association study (GWAS) identifying 14 susceptibility loci for generalized vitiligo. We report here a second GWAS (450 individuals with vitiligo (cases) and 3,182 controls), an independent replication study (1,440 cases and 1,316 controls) and a meta-analysis (3,187 cases and 6,723 controls) identifying 13 additional vitiligo-associated loci. These include OCA2-HERC2 (combined P = 3.80 × 10 ), MC1R (P = 1.82 × 10 ), a region near TYR (P = 1.57 × 10 ), IFIH1 (P = 4.91 × 10 ), CD80 (P = 3.78 × 10 ), CLNK (P = 1.56 × 10 ), BACH2 (P = 2.53 × 10 ), SLA (P = 1.58 × 10 ), CASP7 (P = 3.56 × 10 ), CD44 (P = 1.78 × 10 ), IKZF4 (P = 2.75 × 10 ), SH2B3 (P = 3.54 × 10 ) and TOB2 (P = 6.81 × 10 ). Most vitiligo susceptibility loci encode immunoregulatory proteins or melanocyte components that likely mediate immune targeting and the relationships among vitiligo, melanoma, and eye, skin and hair coloration

    Defining the 'Social' in 'Social Entrepreneurship': Altruism and Entrepreneurship

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    Abstract. What is social entrepreneurship? In, particular, what’s so social about it? Understanding what social entrepreneurship is enables researchers to study the phenomenon and policy-makers to design measures to encourage it. However, such an understanding is lacking partly because there is no universally accepted definition of entrepreneurship as yet. In this paper, we suggest a definition of social entrepreneurship that intuitively accords with what is generally accepted as entrepreneurship and that captures the way in which entrepreneurship may be altruistic. Based on this we provide a taxonomy of social entrepreneurship and identify a number of real cases from Asia illustrating the different forms it could take. Keywords: social entrepreneurship, definition, taxonomy, altruism Social entrepreneurship is a concept that has captured the imagination of many researchers and policy-makers in recent years. Social entrepreneurship suggests that entrepreneurship may be aimed at benefiting society rather than merely maximising individual profits. It appears to promise an altruistic form of capitalism that does not evaluate all human activities in business terms. It enables a bridge to be built between enterprise and benevolence (Roberts and Woods, 2005). The history of the term ‘social entrepreneurship ’ can be traced to the publication of a Demos thinktank report entitled The Rise of the Social Entrepreneur (Leadbeater, 1997) in the United Kingdom and probably a little earlier in the United States to the publication of New Social Entrepreneurs by the Roberts Foundation (Emerson and Twerksy, 1996). Prior to this, some of the activities under the rubric of social entrepreneurship were either termed ‘community development ’ or those in ‘social purpose organizations’. There is considerable use of the term in popular literature although academic literature on it is thin (Taylor, Hobbs, Nilsson, O’Halloran and Preisser, 2000). Recent interest saw a call for papers for a special issue on social entrepreneurship (Honig an

    A heritable subset of the core rumen microbiome dictates dairy cow productivity and emissions

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    A 1000-cow study across four European countries was undertaken to understand to what extent ruminant microbiomes can be controlled by the host animal and to identify characteristics of the host rumen microbiome axis that determine productivity and methane emissions. A core rumen microbiome, phylogenetically linked and with a preserved hierarchical structure, was identified. A 39-member subset of the core formed hubs in co-occurrence networks linking microbiome structure to host genetics and phenotype (methane emissions, rumen and blood metabolites, and milk production efficiency). These phenotypes can be predicted from the core microbiome using machine learning algorithms. The heritable core microbes, therefore, present primary targets for rumen manipulation toward sustainable and environmentally friendly agriculture.R. John Wallace, Goor Sasson, Philip C. Garnsworthy, Ilma Tapio, Emma Gregson ... John L. Williams ... et al

    Safety and efficacy of dry grape extract when used as flavouring in water for drinking for all animal species and categories

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    Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of dry grape extract when added to water for drinking for all animal species and categories. The additive under assessment (dry grape extract) is a mixture of two extracts from the seeds and skin of Vitis vinifera subsp. vinifera. The FEEDAP Panel has previously issued an opinion on the safety and efficacy of this dry grape extract when added to feed. It was concluded that the additive is safe at the maximum proposed use level (100 mg/kg complete feed) for all animal species except dogs, for which no safe dietary concentration could be established. The FEEDAP Panel also concluded that there were no concerns for consumer safety and that no risks for the environment were to be expected and could not conclude on the safety for the user. Since consumer, user and environmental safety are independent of the mode of delivery of the additive, the conclusions reached in the previous opinion also apply to use in water. For a number of target species, the established safe concentration in feed could be exceeded if a maximum proposed dose in water (100 mg/L) was applied. Considering the margin of safety identified in the previous assessment, a maximum concentration of 50 mg/L water for drinking is considered safe for all animal species except dogs. Since the major component of the additive, the proanthocyanidin-rich seed extract, is recognised to provide flavour in food and its function in water for drinking for animals would be essentially the same, no demonstration of efficacy is considered necessary

    5-Lipoxygenase Metabolic Contributions to NSAID-Induced Organ Toxicity

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