2,077 research outputs found

    Development and characterisation of novel microsatellite loci for the baldchin groper (Choerodon rubescens) and cross-amplification in seven other labrid species

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    We describe the development and characterisation of novel microsatellite loci for the baldchin groper, Choerodon rubescens. The purpose was to identify loci that can be used to resolve uncertainties about the population (stock) structure of this fish species, which is endemic to a narrow region of the west coast of Australia and showing evidence of overfishing in some locations. Of 22 loci characterised, 12 appear to be ideally suited for population-level analyses. Utilising data obtained from four sampling locations across the distribution of C. rubescens, the total number of alleles observed at each of the 12 loci ranged from 2 to 24, while the overall values of expected heterozygosity ranged from 0.19 to 0.89. Cross-amplification of the 12 loci in seven other labrid species was often successful, especially in congeners

    Nature's conveyor belt - the matrix mediated biomineralization of magnetite in chitons (Mollusca)

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    Chitons are marine molluscs that use a variety of iron and calcium based minerals to harden their teeth, which they use to scrape algae growing upon, and within, rocks. The teeth are mounted on a long ribbon-like organ termed the radula, with immature, unmineralized teeth at the posterior end and the hardened iron-mineralized teeth at the anterior end (Fig. 1). At any one time, up to 80 individual tooth rows can be observed, with each row becoming progressively mineralized as it moves forward in a conveyor belt-like manner. The ability to study the entire mineralization process in a single animal makes these creatures ideal for the study of matrix mediated biomineralization. The chiton’s ability to mineralize iron has inspired researchers who believe that new biomimetic materials and technologies can be developed based on the principles of biomineral formation

    Fine-scale analysis of biomineralized mollusc teeth using FIB and TEM

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    When it comes to mineral synthesis, there is a lot we can learn from nature. Although we can synthesize a range of materials in the laboratory, the experimental conditions are often constrained to particular ranges of temperature, pH, etc. Biological systems, on the other hand, seem to be able to produce individual minerals and complex composite mineral structures under a variety of conditions, many of which are far from those applied to create their synthetic counterparts. Understanding how nature does this could provide a means to produce novel biomimetic materials with potential applications in a diverse range of fields from medicine to materials engineering

    TIPS AND TRICKS FOR CHARACTERIZING SHAPE MEMORY ALLOY WIRE: PART 4 – THERMO-MECHANICAL COUPLING

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    Disclaimer: The full description of the procedures used in this paper requires the identification of a certain commercial equipment. The inclusion of such information should in no way be construed as indicating that such a product is endorsed or recommended by NIST or that it is necessarily the best for the purposes described. Editor's Note: This ET feature series is intended as an introduction to this exciting area of experimental mechanics. It aims to increase awareness of active materials and to promote their consistent characterization by disseminating best practices from leading researchers in the field. Each article in the series will address the characterization of one commercially significant active material. Series editors: Nilesh D. Mankame and Paul W. Alexander.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79294/1/j.1747-1567.2010.00619.x.pd

    SSR assessment of Phytophthora infestans populations on tomato and potato in British gardens demonstrates high diversity but no evidence for host specialisation

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    Phytophthora infestans populations can differ in composition as a result of host-specialisation on tomato and potato hosts. In Great Britain many amateur gardeners grow outdoor tomatoes but there is little or no commercial tomato production outdoors. This study analysed isolates of P. infestans from British gardens with twelve multiplexed SSR markers that are used to monitor the disease on commercial potato crops. Samples of P. infestans from tomato hosts were collected in three years and from potato in one year from across Great Britain. Seven previously unreported genotypes were detected in garden populations and higher frequencies of unique clonal lineages (28% to 40%) were present compared with populations from British commercial potato crops reported elsewhere. Garden populations had a lower proportion (11% to 48% less) of the most common lineages (13_A2 and 6_A1) which together made up at least 86% of the commercial potato populations during the sampling period. Host species accounted for only 2.6% of molecular variance detected between garden potato- and tomato-hosted samples. No significant difference in clonal lineage composition was found between host species in Great Britain and this could be due to the whole P. infestans population over-wintering on potato. British garden populations on both hosts were much more diverse than those on commercial potato crops; this finding may be influenced by less frequent fungicide use by gardeners and a higher diversity of un-sprayed susceptible potato cultivars enabling metalaxyl-sensitive and less virulent genotypes to survive in gardens

    Professionalism and the Millbank Tendency: The Political Sociology of New Labour's employees

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    This article analyses party employees, one of the most under-researched subjects in the study of British political parties. We draw on a blend of quantitative and qualitative data in order to shed light on the social and political profiles of Labour Party staff, and on the question of their professionalisation. The latter theme is developed through a model derived from the sociology of professions. While a relatively limited proportion of party employees conform to the pure ideal-type of professionalism, a considerably greater number manifest enough of the core characteristics of specialisation, commitment, mobility, autonomy and self-regulation to be reasonably described as 'professionals in pursuit of political outcomes'

    An Evaluation of Techniques for Sampling Skin Flora

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    Three methods of sampling skin bacteria were evaluated to determine whether the large differences observed from adjacent areas of the back were real or due to variability in sampling methods. It was found that in addition to actual differences in the skin flora populations of adjacent areas, there were significant differences in populations obtained by different sampling techniques and significant differences between individuals. Equally high bacterial populations were recovered from skin by the Teflon spatula method and the rayon swab method; however, scrubbing with rayon swabs gave the most consistent results

    Radiometric dates of uplifted marine fauna in Greece:Implications for the interpretation of recent earthquake and tectonic histories using lithophagid dates

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    n AD 365 a great (Mw N 8) earthquake lifted up western Crete, exposing a shoreline encrusted by marine organisms, and up to 10 m of marine substrate beneath it. Radiocarbon ages determined for corals and bryozoans exposed between the paleo-shoreline and present sea level are consistent, within measurement error, with each other and with the date of the earthquake. But radiocarbon ages determined for the boring bivalve Lithophaga lithophaga found on the same substrate are at least 350 years, and up to 2000 years, older than the date of the earthquake that lifted them above sea level. These observations reveal two important effects that limit the use of radiocarbon lithophagid ages in tectonic and paleoseismological studies. The first is that the exceptional preservation potential of lithophagids allows them to remain intact and in situ long after natural death, while the substrate continues to be colonised until eventual uplift. The second, which we confirm with radiocarbon analysis of museum specimens of known age, is the incorporation of old (14C-free) carbon into lithophagid shells from the limestone host rock into which the lithophagids bored. The two effects are both significant in Crete and central Greece, and can cause the radiocarbon lithophagid ages to be up to 2000 years older than the uplift event which exposed them. Understanding these effects is important because lithophagids are far more abundantly preserved, and used to date uplift, than most other marine organisms. This study shows that they can rarely be used to distinguish uplift events, or date them to better than 1000 years, or even to distinguish whether observed uplift occurred in a single or in multiple events. After taking account of these uncertainties, the ages of the lithophagids are, however, consistent with the hypothesis that the highest prominent marine notches and exposed lithophagid holes within a few metres of sea level in Greece formed when sea level became relatively stable ~ 6000 years ago, following rapid rise after the last glacial maximum
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