17,662 research outputs found
Tanarctus arborspinosus Lindgren 1971
No full text129. <i>Tanarctus arborspinosus</i> Lindgren, 1971 <p> <i>Tanarctus arborspinosus</i> nov. spec. (Lindgren 1971)</p> <p> <b> <i>Terra typica</i>: Atlantic Ocean (USA, North America)</b> </p> <p> <b>Atlantic Ocean:</b></p> <p> • <b>34°41′30′′N, 76°50′00′′W;</b> <i>0 m bsl:</i> <b>[FAO31] Type Locality:</b> USA, North Carolina State, Carteret County, Bogue Bank, near Morehead City, ocean side, 30 and 60 cm deep in sand, salinity (34–36‰), sand (0.2–0.5 mm). <b>Lindgren (1971), Renaud-Mornant (1975a)</b></p> <p> <b>Record numbers (Sea/Ocean classification):</b> Atlantic Ocean: 1; <b>total: 1.</b></p> <p> <b>Record numbers (FAO classification):</b> FAO31: 1; <b>total: 1.</b></p> <p> <b>Remarks:</b> This species is known only from the type locality.</p>Published as part of <i>Kaczmarek, Łukasz, Bartels, Paul J., Roszkowska, Milena & Nelson, Diane R., 2015, The Zoogeography of Marine Tardigrada, pp. 1-189 in Zootaxa 4037 (1)</i> on page 121, DOI: 10.11646/zootaxa.4037.1.1, <a href="http://zenodo.org/record/233519">http://zenodo.org/record/233519</a>
Extended chronologies of aqueous alteration in the CM2 carbonaceous chondrites: evidence from carbonates in Queen Alexandra Range 93005
No full textThe Antarctic CM2 carbonaceous chondrite QUE 93005 contains four compositionally distinct carbonates, namely breunnerite, calcite, dolomite and a Ca-poor dolomite. These carbonates can form monomineralic grains, or may be intergrown as bimineralic grains consisting of dolomite plus breunnerite and dolomite plus calcite, or polymineralic grains containing an intergrowth of breunnerite, Ca-poor dolomite and calcite. Carbonates in all grain types have inclusions of Fe,Ni sulphides and/or Mg-Fe phyllosilicates. In the bimineralic grains dolomite crystallised first to be overgrown by breunnerite or partially replaced by calcite. Polymineralic grains are concentrically layered, with breunnerite crystallising first on pore margins to be later etched, then overgrown and partially replaced by Ca-poor dolomite that was itself partly dissolved prior to being overgrown by calcite. Calcite and dolomite have also cemented fractures that cross-cut the fine-grained rims to aqueously altered chondrules and were formed by expansion of the chondrules during their hydration. Overall, the sequence of mineralisation in QUE 93005 was: (1) dolomite, (2) breunnerite, (3) Ca-poor dolomite then (4) calcite. This secular change in carbonate composition and mineralogy reflects changing solution composition and probably also provenance. Mg-Fe phyllosilicates replaced dolomite, breunnerite and Ca-poor dolomite prior to calcite crystallisation and most or all of the sulphides formed after both the phyllosilicates and calcite. Following sulphide crystallisation the edges of carbonate grains were abraded, either by impact ‘gardening’ or as a consequence of fluidisation of the matrix during rapid loss of gas or vapour. Determination of the crystallisation age of dolomite via the MnCr system indicates that aqueous alteration of QUE 93005 began on or before 3.93 ± 0.23 Ma after the formation of the solar system. Overall, the water/rock ratio and <i>f</i>O<sub>2</sub> during alteration of QUE 93005 was similar to that of the CM1s and CR1s, but the lower degree of alteration of QUE 93005 overall suggests that alteration timescales were shorter, possibly due to loss of intergranular liquid water during fluidisation
The politics and economics of regulatory impact assessment
No full textThis is the author accepted manuscript. The final version is available from the publisher via the link in this record
Chromosome 7p linkage and GPR154 gene association in Italian families with asthma
No full textBACKGROUND: Several genome scans have reported linkage of markers on chromosome 7p with asthma and related phenotypes in different populations. A fine mapping in Finnish and French-Canadian populations has associated the GPR154 gene (also known as G-protein-coupled receptor for asthma susceptibility, GPRA) with elevated IgE or asthma.OBJECTIVE: To confirm chromosome 7p linkage and candidate gene association in Italian families with atopic asthma.METHODS: In a two-phase approach, we first performed a linkage analysis of chromosome 7, and then a family-based association study on the GPR154 gene for allergic asthma phenotypes in the Italian population.RESULTS: The screening of 117 families with 19 microsatellite markers showed potential linkage for elevated IgE (P<0.002 at 22 cM from p-ter), asthma (P<0.005 at 44 cM), or atopy (P<0.005 at 54 cM). In the second phase of the present study, candidate gene GPR154, which is located in the phase one-linked region, was investigated in 211 families with seven single nucleotide polymorphisms (SNPs) that tag most haplotype variability, by the pedigree disequilibrium test. Elevated IgE levels were associated with two GPR154 gene SNPs (SNP 546333, P=0.0046; rs740 347, P=0.006), and with haplotypes in the global test (P=0.013). Haplotype analysis performed in nuclear families having at least 1 asthmatic parent showed a significant association with asthma (P=0.0173), atopy (P=0.0058), SPT (P=0.0025), and bronchial hyper reactivity (P=0.0163).CONCLUSION: These results support a susceptibility locus for asthma and related phenotypes on chromosome 7, and are in agreement with recent reports suggesting that a common susceptibility factor for atopic manifestations in asthma is likely conferred by the locus containing the GPR154 gene
Multiplication of Four \u3cem\u3ePenstemon\u3c/em\u3e Species \u3cem\u3ein vitro\u3c/em\u3e
No full textPenstemon (beard tongue) is a native genus of U.S. wildflower that is used for landscape plants (Lindgren, 1984a, 1984b, 1990), for cut flowers (Lindgren, 1986), and for ecological studies (Stubbendieck et al., 1982). Tissue culture techniques could be useful for propagating cultivars and species in this genus as some do not breed true from seed, require special seed germination conditions, or are difficult to propagate using other vegetative methods (Lindgren, 1984b, 1990; Stubbendieck et al., 1982). Penstemon haydenii is also the only listed endangered plant species in Nebraska.
The Penstemon spp. P. digitalis Nutt. ‘Husker Red’ (Lindgren, 1984b); P. grandiflorus Nutt. ‘Prairie Snow’ (Lindgren, 1990); P. barbatus (Cav.) Roth ‘Schooley’s Yellow’ (Lindgren, 1984a), and P. haydenii S. Wats (Stubbendieck et al., 1982) were evaluated for their growth response to five levels of N- (phenylmethyl)-1H purine-6-amine (BA).
Lateral buds from greenhouse-grown plants of each of the four species were surface sterilized by sequential immersion in 75% ethanol for 1 min and 0.53% NaOCl for 15 min, followed by rinsing three times in sterile water. Explants were then placed in 120-m] baby food jars with polypropylene closures that contained 30 ml Woody Plant Medium (Lloyd and McCown, 1980) with 0.1% (w/v) Gelrite, 0.3% (w/v) Sigma agar, 2% (w/v) sucrose, 6 mM calcium gluconate, and 0.4 μM BA. Shoots were grown on this medium for 8 weeks, then transferred to Murashige and Skoog (MS) basal medium (Murashige and Skoog, 1962) without BA and grown for 6 weeks. Shoot sections with one node each were then transferred to 30 ml MS medium, placed vertically, and supplemented with either 0, 0.01, 0.1, 1.0, or 10.0 μM BA. At the end of 4 weeks, shoot tips (1 cm) were transferred to fresh MS media supplemented with the same concentrations of BA and, at the end of 6 weeks, plant growth was measured. All tissue culture media were adjusted to a pH of 5.7. Growth rooms were maintained at 27 ± 1C with 24 h continuous light provided by cool-white fluorescent bulbs (20 μmol·m–2·s–1). The experimental design was a randomized complete block with five replicates per treatment. One replicate consisted of one jar with one shoot per jar. Statistical comparisons were made between BA levels only within each species
Phase Distribution Efficiency of cm-Scale Ultrasonically Powered Receivers
No full textIn the domain of ultrasonically powered biomedical implants, there is an increasing interest in cm-scale ultrasonic receivers (RX). However, when a single-element transducer is used as the RX transducer, an uneven phase distribution across the RX area can significantly reduce the harvestable power. In this paper, we investigate the impact of lateral and angular misalignment on the acoustic field phase distribution across the RX surface. We show that, for a single-element RX transducer, lateral misalignment has minimal effect on the harvestable power, whereas even small angular misalignments can cause a considerable reduction, especially for larger RX sizes. We present a potential solution that consists of subdividing a large RX transducer (e.g. 20 × 20mm2) into smaller elements, which significantly improves power transfer efficiency by taking advantage of the smaller phase variation across the surface of each element. The trade-offs between achieving a minimum acceptable power transfer efficiency and managing the increased complexity in packaging and matching circuitry are also discussed.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and MaterialsBio-Electronic
Highly efficient laser-driven Compton gamma-ray source
No full textThe recent advancement of high-intensity lasers has made all-optical Compton scattering become a promising way to produce ultrashort brilliant gamma-rays in an ultra-compact system. However, so far achieved Compton gamma-ray sources are limited by low conversion efficiency and spectral intensity. Here we present a highly efficient gamma photon emitter obtained by irradiating a high-intensity laser pulse on a miniature plasma device consisting of a plasma lens and a plasma mirror. This concept exploits strong spatiotemporal laser-shaping process and high-charge electron acceleration process in the plasma lens, as well as an efficient nonlinear Compton scattering process enabled by the plasma mirror. Our full three-dimensional particle-in-cell simulations demonstrate that in this novel scheme, brilliant gamma-rays with very high conversion efficiency (higher than 10(-2)) and spectral intensity (similar to 10(9) photons/0.1%BW) can be achieved by employing currently available petawatt-class lasers with intensity of 10(21) W cm(-2). Such efficient and intense gamma-ray sources would find applications in wide-ranging areas. ©2019 The Author(s)
A microchondrule-bearing micrometeorite and comparison with microchondrules in CM chondrites
No full textWe report the discovery of a partially altered microchondrule within a fine-grained micrometeorite.This object is circular, <10μm in diameter and has a cryptocrystalline texture, internal zonation and a thin S-bearing rim. These features imply a period of post-accretion parent body aqueous alteration, in which the former glassy igneous texture was subject to hydration and phyllosilicate formation as well as leaching of fluid-mobile elements. We compare this microchondrule to three microchondrules found in two CM chondrites: Elephant Moraine (EET) 96029 and Murchison. In all instances, their formation appears closely linked to the late-stages of chondrule formation, chondrule recycling and fine-grained rim accretion. Likewise, they share cryptocrystalline textures and evidence of mild aqueous alteration and thus similar histories. We also investigate the host micrometeorite’s petrology, which includes an unusually Cr-rich mineralogy, containing both Mn-chromite spinel and low-Fe-Cr rich (LICE) anhydrous silicates. Because these two refractory phases cannot form together in a single geochemical reservoir under equilibrium condensation, this micrometeorite’s accretionary history requires a complex timeline with formation via non-equilibrium batch crystallization or accumulation of materials from large radial distances. In contrast, the bulk composition of this micrometeorite and its internal textures are consistent with a hydrated carbonaceous chondrite source. This micrometeorite is interpreted as a fragment of fine-grained rim material that once surrounded a larger parent chondrule and was derived from a primitive carbonaceous parent body; either a CM chondrite or Jupiter family comet
Tracking the Earliest Stages of Aqueous Alteration in the Mildly Altered CM Chondrite EET 96029
No full textThe earliest stages of CM carbonaceous
chondrite aqueous alteration are very poorly
understood as mildly altered CMs are extremely rare.
The Paris meteorite (CM2.7) [1-3] and QUE 97990
(CM2.6) [4,5] are among the least aqueously altered
CMs described to date. However, neither of them contain
the pristine attribute of chondrule mesostasis glass.
Glass is highly reactive and so among the very first
phases to undergo aqueous alteration [6]. Therefore,
the CM carbonaceous chondrite EET 96029 is very
unusual as it has been shown to have retained
mesostasis glass in at least one chondrule [7]. According
to the new CM classification scheme of [8], which
is based on H content, EET 96029 has an index of 2.0
(data in [9]), meaning that it is less altered than all but
one of the fifty CMs analysed by [8]. A caveat is that a
low H content could be due to mild heating as well as a
low degree of aqueous processing [9]. However, the
bulk O oxygen isotope composition of EET 96029 (as
determined by [10]) is consistent with a low degree of
alteration as it is slightly closer to that of the CO3 falls
(possible representatives of the anhydrous progenitors
of the CMs) than even the least altered lithology of
Paris (Fig. 1).
To better understand the earliest stages of CM
aqueous alteration and its impact on mesostasis glass,
we have undertaken a detailed study of chondrule
mesostasis textures and compositions in the mildly
aqueously altered CM chondrite EET 96029.</p
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