1,219 research outputs found

    The Amplification of the Chinese Hamster Ovary Glutamine Synthetase Gene and Its Flanking DNA

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    By multistep selection of cells for increasing resistance to methionine sulphoximine, a specific inhibitor of glutamine synthetase, an amplified cell line was produced with approximately 1000 copies of the glutamine synthetase (GS) gene. The genomic GS gene was isolated from the DNA of this cell line and the cloned DNA used to probe the regions flanking the GS gene. By conventional agarose gel electrophoresis it was shown that the DNA containing the GS gene was homogeneous for at least 40 kbp in all copies of the GS amplification unit and that the hypomethylation patterns at the 5' of the GS gene were also homogeneous. An estimate of the size of the amplified unit suggested that it was 60 kbp in size. Pulse field gel electrophoresis was used to analysis the relationship of one unit to another and several possible models are discussed. PFGE suggested that a single unit was 75 kbp in size and analysis of other related cell lines suggested that this size is a reduction from the size of the unit in a less amplified line. Karyotypic and in situ hybridization studies of the parental and highly amplified cell line revealed the presence of several rearranged marker chromosomes one of which was shown to be the site of the amplified DNA

    Young people and ICT 2002: findings from a survey conducted in Autumn 2002

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    This report describes a survey that explored the attitudes and experiences of young people aged 5-18 and their parents, in relation to the use of information and communications technology (ICT) at home and at schoo

    Swimming capabilities of stoats and the threat to inshore sanctuaries

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    Stoats (Mustela erminea) are small carnivorous mammals which were introduced into New Zealand in the late 19th century, and have now become widespread invasive pests. Stoats have long been known to be capable of swimming to islands 1-1.5 km offshore. Islands further out have usually been assumed to be safe from invasion, therefore routine stoat monitoring on them has been considered un-necessary. Recent incursions, including a stoat found on Rangitoto Island (3 km offshore) in 2010, and another which was deduced to have reached Kapiti (5 km offshore) in 2009, along with distribution modelling and genetic studies, strongly support the proposition that stoats can swim much further than 1.5 km. Acceptance of this hypothesis depends on estimating the probability that such small animals could indeed swim so far unaided. This paper reports the results of a project designed to assist this debate by recording the paddling action, speed and minimal endurance of nine stoats observed (once each) swimming against an endless current in a flume at the Aquatic Research Centre, University of Waikato. Four of the five males and two of the four females could hold a position for at least five minutes against the maximum current available, averaging 1.36 ± 0.336 km/h. In steady swimming against a current of c. 1 km/hr, they all used a rapid quadripedal paddling action (averaging 250 strokes/min, stronger with the spread forepaws). Four of the nine swam strongly for >1 h, including one female who covered 1.8 km in nearly 2 h non- stop. Results from such artificial conditions cannot be conclusive, but support suggestions that wild stoats could indeed swim much further than 1.5 km, hence we conclude that the “risk zone” for stoat reinvasions of inshore islands has been seriously under-estimated

    Coloring Artemis graphs

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    We consider the class A of graphs that contain no odd hole, no antihole, and no ``prism'' (a graph consisting of two disjoint triangles with three disjoint paths between them). We show that the coloring algorithm found by the second and fourth author can be implemented in time O(n^2m) for any graph in A with n vertices and m edges, thereby improving on the complexity proposed in the original paper

    Evidence for Past Subduction Earthquakes at a Plate Boundary with Widespread Upper Plate Faulting: Southern Hikurangi Margin, New Zealand

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    At the southern Hikurangi margin, New Zealand, we use salt marsh stratigraphy, sedimentology, micropaleontology, and radiocarbon dating to document evidence of two earthquakes producing coseismic subsidence and (in one case) a tsunami over the past 1000 yrs. The earthquake at 520-470 yrs before present (B.P.) produced 0.25 +/- 0.1 m of subsidence at Big Lagoon. The earthquake at 880-800 yrs B.P. produced 0.45 +/- 0.1 m of subsidence at Big Lagoon and was accompanied by a tsunami that inundated >= 360 m inland with a probable height of >= 3.3 m. Distinguishing the effects of upper plate faulting from plate interface earthquakes is a significant challenge at this margin. We use correlation with regional upper plate paleoearthquake chronologies and elastic dislocation modeling to determine that the most likely cause of the subsidence and tsunami events is subduction interface rupture, although the older event may have been a synchronous subduction interface and upper plate fault rupture. The southern Hikurangi margin has had no significant (M > 6.5) documented subduction interface earthquakes in historic times, and previous assumptions that this margin segment is prone to rupture in large to great earthquakes were based on seismic and geodetic evidence of strong contemporary plate coupling. This is the first geologic evidence to confirm that the southern Hikurangi margin ruptures in large earthquakes. The relatively short-time interval between the two subduction earthquakes (similar to 350 yrs) is shorter than in current seismic-hazard models.GNSEQC Biennial ProjectNew Zealand Natural Hazards Research Platform and Foundation for Research Science and TechnologyInstitute for Geophysic

    Determining the stellar masses of submillimetre galaxies: the critical importance of star formation histories

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    Submillimetre (submm) galaxies are among the most rapidly star-forming and most massive high-redshift galaxies; thus, their properties provide important constraints on galaxy evolution models. However, there is still a debate about their stellar masses and their nature in the context of the general galaxy population. To test the reliability of their stellar mass determinations, we used a sample of simulated submm galaxies for which we derived stellar masses via spectral energy distribution (SED) modelling (with Grasil, Magphys, Hyperz and LePhare) adopting various star formation histories (SFHs). We found that the assumption of SFHs with two independent components leads to the most accurate stellar masses. Exponentially declining SFHs (tau) lead to lower masses (albeit still consistent with the true values), while the assumption of single-burst SFHs results in a significant mass underestimation. Thus, we conclude that studies based on the higher masses inferred from fitting the SEDs of real submm galaxies with double SFHs are most likely to be correct, implying that submm galaxies lie on the high-mass end of the main sequence of star-forming galaxies. This conclusion appears robust to assumptions of whether or not submm galaxies are driven by major mergers, since the suite of simulated galaxies modelled here contains examples of both merging and isolated galaxies. We identified discrepancies between the true and inferred stellar ages (rather than the dust attenuation) as the primary determinant of the success/failure of the mass recovery. Regardless of the choice of SFH, the SED-derived stellar masses exhibit a factor of ~2 scatter around the true value; this scatter is an inherent limitation of the SED modelling due to simplified assumptions. Finally, we found that the contribution of active galactic nuclei does not have any significant impact on the derived stellar masses.Comment: Accepted to A&A. 11 pages, 9 figures, 1 table. V2 main changes: 1) discussion of the stellar age as the main parameter influencing the success of an SED model (Fig. 4, 5, 7); 2) discussion of the age-dust degeneracy (Fig 9); 3) the comparison of real and simulated submm galaxies (Fig 1

    Gratitude to God, Self‐Rated Health, and Depressive Symptoms

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107511/1/jssr12110.pd

    Taxonomy and biogeography of living species of the Family Notorotaliidae (Notorotalia, Parrellina, Porosorotalia, Buccella, Cristatavultus)

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    DNA sequencing shows that species of the genera Notorotalia, Porosorotalia and Buccella form a distinct branch (Notorotaliidae) of Rotaloidea, and cluster as sister to Elphidiidae. In this review we report on the sequencing of three species of Buccella (from the Arctic Ocean, Patagonia and Chile) and one each of Notorotalia (New Zealand) and Porosorotalia (Chile). This information has been combined with all the morphological descriptive information on species of these genera plus the genera Cristatavultus and Parrellina to provide a global synthesis of living species of the Notorotaliidae. We recognize 11 species of the southern hemisphere genus Notorotalia, which has a centre of diversity around New Zealand (8 species). A second southern-hemisphere-restricted genus, restricted to eastern Australia is Parrellina (3 species) although specimens (possibly introduced) have been recorded from the Mediterranean Sea. Cristatavultus has a single species, with a tropical west Pacific distribution.We synonymize Cribrorotalia under Porosorotalia, which has a disjunct distribution with one species in the northwest Pacific and a second around the southern parts of South America. Buccella is the most diverse and widespread genus (16 species recognized) with its greatest abundance in the Arctic Ocean and around subantarctic-temperate South America. Five species of Buccella live in a belt along the west coast of central America, from USAto Peru, with some spillage into the Caribbean Sea and Gulf of Mexico. Two new species of Buccella are recognized: B. dejardini (from South Georgia) and Buccella n. sp. A (from Chile)
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