20 research outputs found

    First report of mitochondrial COI in foraminifera and implications for DNA barcoding

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    Foraminifera are a species-rich phylum of rhizarian protists that are highly abundant in many marine environments and play a major role in global carbon cycling. Species recognition in Foraminifera is mainly based on morphological characters and nuclear 18S ribosomal RNA barcoding. The 18S rRNA contains variable sequence regions that allow for the identification of most foraminiferal species. Still, some species show limited variability, while others contain high levels of intragenomic polymorphisms, thereby complicating species identification. The use of additional, easily obtainable molecular markers other than 18S rRNA will enable more detailed investigation of evolutionary history, population genetics and speciation in Foraminifera. Here we present the first mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences ("barcodes") of Foraminifera. We applied shotgun sequencing to single foraminiferal specimens, assembled COI, and developed primers that allow amplification of COI in a wide range of foraminiferal species. We obtained COI sequences of 49 specimens from 17 species from the orders Rotaliida and Miliolida. Phylogenetic analysis showed that the COI tree is largely congruent with previously published 18S rRNA phylogenies. Furthermore, species delimitation with ASAP and ABGD algorithms showed that foraminiferal species can be identified based on COI barcodes.Microbial BiotechnologyNaturali

    Power Problems in VLSI Circuit Testing ⋆

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    Abstract. Controlling or reducing power consumption during test and reducing test time are conflicting goals. Weighted random patterns (WRP) and transition density patterns (TDP) can be effectively deployed to reduce test length with higher fault coverage in scan-BIST circuits. New test pattern generators (TPG) are proposed to generate weighted random patterns and controlled transition density patterns to facilitate efficient scan-BIST implementations. We achieve reduction in test application time without sacrificing fault coverage while maintaining any given test power constrain by dynamically adapting the scan clock, accomplished by a built-in hardware monitor of transition density in the scan register

    Experimental studies of complex crater formation under cluster implantation of solids

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    The results of a systematic study of surface defect formation after energetic Arn+_n^+ (n = 12, 22, 32, 54) and Xen+_n^+ (n = 4, 16) cluster ion implantation into silicon and sapphire are presented. Implantation energies vary from 3 to 18 keV/ion. Two cases of comparative studies are carried out: the same cluster species are implanted into two different substrates, i.e. Arn+_n^+ cluster ions into silicon and sapphire and two different cluster species Arn+_n^+ and Xen+_n^+ are implanted into the same kind of substrate (silicon). Atomic force, scanning electron and transmission electron microscopies (AFM, SEM and TEM) are used to study the implanted samples. The analysis reveals the formation of two types of surface erosion defects: simple and complex (with centrally positioned hillock) craters. It is found that the ratio of simple to complex crater formation as well as the hillock dimensions depend strongly on the cluster species, size and impact energy as well as on the type of substrate material. Qualitative models describing the two comparative cases of cluster implantation, the case of different cluster species and the case of different substrate materials, are proposed
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