136 research outputs found

    Development of a prototype plastic space erectable satellite Quarterly report, Jun. - Aug. 1966

    Get PDF
    Copper plated high-density polyethylene film evaluation for space erectable satellite desig

    Instrumental neutron activation analysis of an enriched 28Si single-crystal

    Full text link
    The determination of the Avogadro constant plays a key role in the redefinition of the kilogram in terms of a fundamental constant. The present experiment makes use of a silicon single-crystal highly enriched in 28Si that must have a total impurity mass fraction smaller than a few parts in 109. To verify this requirement, we previously developed a relative analytical method based on neutron activation for the elemental characterization of a sample of the precursor natural silicon crystal WASO 04. The method is now extended to fifty-nine elements and applied to a monoisotopic 28Si single-crystal that was grown to test the achievable enrichment. Since this crystal was likely contaminated, this measurement tested also the detection capabilities of the analysis. The results quantified contaminations by Ge, Ga, As, Tm, Lu, Ta, W and Ir and, for a number of the detectable elements, demonstrated that we can already reach the targeted 1 ng/g detection limit.Comment: 9 pages, 1 figure, 1 tabl

    Early Science with the Large Millimetre Telescope: Molecules in the Extreme Outflow of a proto-Planetary Nebula

    Get PDF
    Extremely high velocity emission likely related to jets is known to occur in some proto-Planetary Nebulae. However, the molecular complexity of this kinematic component is largely unknown. We observed the known extreme outflow from the proto-Planetary Nebula IRAS 16342-3814, a prototype water fountain, in the full frequency range from 73 to 111 GHz with the RSR receiver on the Large Millimetre Telescope. We detected the molecules SiO, HCN, SO, and 13^{13}CO. All molecular transitions, with the exception of the latter are detected for the first time in this source, and all present emission with velocities up to a few hundred km s1^{-1}. IRAS 16342-3814 is therefore the only source of this kind presenting extreme outflow activity simultaneously in all these molecules, with SO and SiO emission showing the highest velocities found of these species in proto-Planetary Nebulae. To be confirmed is a tentative weak SO component with a FWHM \sim 700 km s1^{-1}. The extreme outflow gas consists of dense gas (nH2>_{\rm H_2} > 104.8^{4.8}--105.7^{5.7} cm3^{-3}), with a mass larger than \sim 0.02--0.15 M_{\odot}. The relatively high abundances of SiO and SO may be an indication of an oxygen-rich extreme high velocity gas.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society Letter

    Dujardinascaris helicina (Nematoda: Ascarididae) parásito de Crocodylus acutus (Reptilia: Crocodylidae) en Puerto Vallarta, Jalisco, México

    Get PDF
    ResumenEl cocodrilo de río (Crocodylus acutus, Cuvier, 1807) es una especie protegida en México. En este trabajo se han estudiado los contenidos obtenidos por medio de lavados gástricos a 53C. acutus, en las áreas del estero el Salado, estero Boca Negra-Boca de Tomates y en la UMA Reptilario Cipactli, ubicadas en Puerto Vallarta, Jalisco, México, con el fin de conocer la helmintofauna de la especie. Se identificó solamente al nemátodo, Dujardinascaris helicina (Molin, 1860). La mayor prevalencia fue del 74% y la abundancia 3.17 en el área del estero Boca Negra-Boca de Tomates; y la menor prevalencia fue del 12%, con una abundancia de 0.76 en los ejemplares en la UMA Reptilario Cipactli. Suponemos que esta diferencia se debe principalmente al tipo de alimento suministrado a los cocodrilos en cautiverio. En esta investigación se registra por primera vez a D. helicina como parásito de C. acutus en la región.AbstractThe river crocodile (Crocodylus acutus, Cuvier, 1807) is a protected species in Mexico. In this work the stomach contents obtained through gastric lavage of 53 C. acutus from the estuarine systems “El Salado”, “Boca Negra-Boca de Tomates” and from the “UMA (Unidad de Manejo y Conservación de Vida Silvestre” for its meaning in Spanish) Reptilario Cipactli” located in Puerto Vallarta, Jalisco, Mexico were collected to study the helminth fauna of the species. Only Dujardinascaris helicina (Molin, 1860) was identified. The highest prevalence occurred in “Boca Negra-Boca de Tomates” with 74% and an abundance of 3.17, and the lowest in “UMA Reptilario Cipactli” with 12% and an abundance of 0.76. The dissimilarity is assumed to be caused primarily by the different feeding habits between wildlife and captivity raised crocodiles. During this investigation D. helicina is registered for the first time as a parasite for C. acutus in the region

    MAPlex: A massively parallel sequencing ancestry analysis multiplex for Asia-Pacific populations

    Get PDF
    © 2019 The Authors Current forensic ancestry-informative panels are limited in their ability to differentiate populations in the Asia-Pacific region. MAPlex (Multiplex for the Asia-Pacific), a massively parallel sequencing (MPS) assay, was developed to improve differentiation of East Asian, South Asian and Near Oceanian populations found in the extensive cross-continental Asian region that shows complex patterns of admixture at its margins. This study reports the development of MAPlex; the selection of SNPs in combination with microhaplotype markers; assay design considerations for reducing the lengths of microhaplotypes while preserving their ancestry-informativeness; adoption of new population-informative multiple-allele SNPs; compilation of South Asian-informative SNPs suitable for forensic AIMs panels; and the compilation of extensive reference and test population genotypes from online whole-genome-sequence data for MAPlex markers. STRUCTURE genetic clustering software was used to gauge the ability of MAPlex to differentiate a broad set of populations from South and East Asia, the West Pacific regions of Near Oceania, as well as the other globally distributed population groups. Preliminary assessment of MAPlex indicates enhanced South Asian differentiation with increased divergence between West Eurasian, South Asian and East Asian populations, compared to previous forensic SNP panels of comparable scale. In addition, MAPlex shows efficient differentiation of Middle Eastern individuals from Europeans. MAPlex is the first forensic AIM assay to combine binary and multiple-allele SNPs with microhaplotypes, adding the potential to detect and analyze mixed source forensic DNA

    Search for galactic axions with a high-Q dielectric cavity

    Full text link
    A haloscope of the QUAX--aγa\gamma experiment, composed of an high-Q resonant cavity immersed in a 8 T magnet and cooled to 4.5\sim 4.5~K is operated to search for galactic axion with mass ma42.8 μeVm_a\simeq42.8~\mu\text{eV}. The design of the cavity with hollow dielectric cylinders concentrically inserted in a OFHC Cu cavity, allowed us to maintain a loaded quality-factor Q 300000\sim 300000 during the measurements in presence of magnetic field. Through the cavity tuning mechanism it was possible to modulate the resonance frequency of the haloscope in the region 10.3533710.3534510.35337-10.35345~GHz and thus acquire different dataset at different resonance frequencies. Acquiring each dataset for about 50 minutes, combining them and correcting for the axion's signal estimation-efficiency we set a limit on the axion-photon coupling gaγγ<0.731×1013g_{a\gamma\gamma}< 0.731\times10^{-13} GeV1^{-1} with the confidence level set at 90%90\%

    The NIKA2 large-field-of-view millimetre continuum camera for the 30 m IRAM telescope

    Get PDF
    Context. Millimetre-wave continuum astronomy is today an indispensable tool for both general astrophysics studies (e.g. star formation, nearby galaxies) and cosmology (e.g. cosmic microwave background and high-redshift galaxies). General purpose, large-field-of-view instruments are needed to map the sky at intermediate angular scales not accessible by the high-resolution interferometers (e.g. ALMA in Chile, NOEMA in the French Alps) and by the coarse angular resolution space-borne or ground-based surveys (e.g. Planck, ACT, SPT). These instruments have to be installed at the focal plane of the largest single-dish telescopes, which are placed at high altitude on selected dry observing sites. In this context, we have constructed and deployed a three-thousand-pixel dual-band (150 GHz and 260 GHz, respectively 2 mm and 1.15 mm wavelengths) camera to image an instantaneous circular field-of-view of 6.5 arcmin in diameter, and configurable to map the linear polarisation at 260 GHz. Aims. First, we are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focussing on the cryogenics, optics, focal plane arrays based on Kinetic Inductance Detectors, and the readout electronics. The focal planes and part of the optics are cooled down to the nominal 150 mK operating temperature by means of an adhoc dilution refrigerator. Secondly, we are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-m IRAM telescope at Pico Veleta, near Granada (Spain). Methods. We have targeted a number of astronomical sources. Starting from beam-maps on primary and secondary calibrators we have then gone to extended sources and faint objects. Both internal (electronic) and on-the-sky calibrations are applied. The general methods are described in the present paper. Results. NIKA2 has been successfully deployed and commissioned, performing in-line with expectations. In particular, NIKA2 exhibits full width at half maximum angular resolutions of around 11 and 17.5 arcsec at respectively 260 and 150 GHz. The noise equivalent flux densities are, at these two respective frequencies, 33±2 and 8±1 mJy s1/2. A first successful science verification run was achieved in April 2017. The instrument is currently offered to the astronomy community and will remain available for at least the following ten years

    Wandering near the red edge: photometric observations of three cool ZZ Ceti stars

    Get PDF
    We summarize our findings on three cool ZZ Ceti type pulsating white dwarfs. We determined eight independent modes in HS 0733+4119, of which seven are new findings. For GD 154, we detected two new eigenmodes, and the recurrence of the pulsational behaviour first observed in 1977. We discuss that GD 154 does not only vary its pulsations between a multiperiodic and a quasi-monoperiodic phase, but there are also differences between the relative amplitudes of the near-subharmonics observed in the latter phase. In the complex pulsator, Ross 808, we compared the pre- and post Whole Earth Telescope campaign measurements, and determined two new frequencies besides the ones observed during the campaign. Studying these stars can contribute to better understanding of pulsations close to the empirical ZZ Ceti red edge. All three targets are in that regime of the ZZ Ceti instability strip where short-term amplitude variations or even outbursts are likely to occur, which are not well-understood theoretically.Comment: 15 pages, 13 figures, accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Replication of fifteen loci involved in human plasma protein N-glycosylation in 4,802 samples from four cohorts

    Get PDF
    Human protein glycosylation is a complex process, and its in vivo regulation is poorly understood. Changes in glycosylation patterns are associated with many human diseases and conditions. Understanding the biological determinants of protein glycome provides a basis for future diagnostic and therapeutic applications. Genome-wide association studies (GWAS) allow to study biology via a hypothesis-free search of loci and genetic variants associated with a trait of interest. Sixteen loci were identified by three previous GWAS of human plasma proteome N-glycosylation. However, the possibility that some of these loci are false positives needs to be eliminated by replication studies, which have been limited so far. Here, we use the largest set of samples so far (4,802 individuals) to replicate the previously identified loci. For all but one locus, the expected replication power exceeded 95%. Of the sixteen loci reported previously, fifteen were replicated in our study. For the remaining locus (near the KREMEN1 gene) the replication power was low, and hence replication results were inconclusive. The very high replication rate highlights the general robustness of the GWAS findings as well as the high standards adopted by the community that studies genetic regulation of protein glycosylation. The fifteen replicated loci present a good target for further functional studies. Among these, eight genes encode glycosyltransferases: MGAT5, B3GAT1, FUT8, FUT6, ST6GAL1, B4GALT1, ST3GAL4, and MGAT3. The remaining seven loci offer starting points for further functional follow-up investigation into molecules and mechanisms that regulate human protein N-glycosylation in vivo
    corecore