536 research outputs found

    Aspects of the Biology of Spilocuma salomani (Cumacea: Boditriidae)

    Get PDF

    Fishes of the Nearshore Zone of St. Andrew Bay, Florida and Adjacent Coast

    Get PDF
    The catch of fish by beach seine at 17 stations in the nearshore zone of St. Andrew Bay and adjacent coast during 1974 and 1975 was studied. A total of 99,579 individuals representing 88 species and 41 families was collected. The bay system and adjacent coast were divided into four areas based upon salinity, turbidity, amount of attached vegetation, and bottom type. The central bay (Area I) had the largest catches by weight (211.3 kg), number of individuals (52,322), standing crop (37.5 kg/ha) and species (61). This area was dominated by four species (Menidia beryllina, Lagodon rhomboides, Eucinostomus argenteus and Leiostomus xanthurus), which made up 94.5% of the total catch. The upper bays (Area II) had the second highest catches (34,665), second highest standing crop (23.4 kg/ha), second highest catches by weight (115.5 kg), and second highest number of species (52). Five species (M. beryllina, Fundulus similis, L. xanthurus, Lucania parva, and Cyprinodon variegatus) comprised 75.7% of the collections from this area. Upper North Bay (Area III) had lower catches (3,002), lower catches by weight (17.4 kg), and lower standing crop (17.6 kg/ha) than Area II. Area III had the least number of species (25) and the area was dominated by three species (E. argenteus, M. beryllina, and F. similis), which accounted for 76.2% of the total catch for this area. The gulf beach stations (Area IV) had the lowest catches (1,918), second lowest catches by weight (37 kg), and lowest standing crop (7.5 kg/ha). A total of 44 species was reported from this area. Area IV was dominated by one species (Harengula jaguana), which made up 66.1% of the total from these stations

    Trace Element Analysis of Potassium by Resonance Ionization Mass Spectrometry

    Full text link
    A simple resonance ionization mass spectrometer is built with a Quadrupole Mass Spectrometer (QMS) and two laser diodes aiming at trace analysis of potassium. The overall detection efficiency is estimated comparing the yields of resonance ionization and electron-impact ionization in the same QMS. A clear discrimination of 39K^{39}\rm K, 40K^{40}\rm K and 41K^{41}\rm K is demonstrated with a help of isotope shifts of the atomic levels.Comment: 14 pages, 9 figures, submitted to JJA

    Ionization balance of Ti in the photospheres of the Sun and four late-type stars

    Full text link
    In this paper we investigate statistical equilibrium of Ti in the atmospheres of late-type stars. The Ti I/Ti II level populations are computed with available experimental atomic data, except for photoionization and collision induced transition rates, for which we have to rely on theoretical approximations. For the Sun, the NLTE line formation with adjusted H I inelastic collision rates and MAFAGS-OS model atmosphere solve the long-standing discrepancy between Ti I and Ti II lines. The NLTE abundances determined from both ionization stages agree within 0.010.01 dex with each other and with the Ti abundance in C I meteorites. The Ti NLTE model does not perform similarly well for the metal-poor stars, overestimating NLTE effects in the atmospheres of dwarfs, but underestimating overionization for giants. Investigating different sources of errors, we find that only [Ti/Fe] ratios based on Ti II and Fe II lines can be safely used in studies of Galactic chemical evolution. To avoid spurious abundance trends with metallicity and dwarf/giant discrepancies, it is strongly recommended to disregard Ti I lines in abundance analyses, as well as in determination of surface gravities.Comment: 16 pages, accepted for publication in MNRA

    Wavelengths and oscillator strengths of Xe II from the UVES spectra of four HgMn stars

    Full text link
    In spite of large overabundances of Xe II observed in numerous mercury-manganese (HgMn) stars, Xe II oscillator strengths are only available for a very limited number of transitions. As a consequence, several unidentified lines in the spectra of HgMn stars could be due to Xe II. In addition, some predicted Xe II lines are redshifted by about 0.1 A from stellar unidentified lines, raising the question about the wavelength accuracy of the Xe II line data available in the literature. For these reasons we investigated the Xe II lines lying in the 3900-4521 A, 4769-7542 A, and 7660-8000 A spectral ranges of four well-studied HgMn stars. We compared the Xe II wavelengths listed in the NIST database with the position of the lines observed in the high-resolution UVES spectrum of the xenon-overabundant, slowly rotating HgMn stars HR 6000, and we modified them when needed. We derived astrophysical oscillator strengths for all the Xe II observed lines and compared them with the literature values, when available. In this framework, we performed a complete abundance analysis of HD 71066, while we relied on our previous works for the other stars. We find that all the lines with wavelengths related to the 6d and 7s energy levels have a corresponding unidentified spectral line, blueshifted by the same quantity of about 0.1 A in all the four stars, so that we identified these lines as coming from Xe II and modified their NIST wavelength value according to the observed stellar value. We find that the Xe II stellar oscillator strengths may differ from one star to another from 0.0 dex to 0.3 dex. We adopted the average of the oscillator strengths derived from the four stars as final astrophysical oscillator strength.Comment: Paper was accepted by A&A for publicatio

    Voluntary self-touch increases body ownership

    Get PDF
    Experimental manipulations of body ownership have indicated that multisensory integration is central to forming bodily self representation. Voluntary self touch is a unique multisensory situation involving corresponding motor, tactile and proprioceptive signals. Yet, even though self-touch is frequent in everyday life, its contribution to the formation of body ownership is not well understood. Here we investigated the role of voluntary self touch in body ownership using a novel adaptation of the rubber hand illusion (RHI), in which a robotic system and virtual reality allowed participants self-touch of real and virtual hands. In the first experiment, active and passive self-touch were applied in the absence of visual feedback. In the second experiment, we tested the role of visual feedback in this bodily illusion. Finally, in the third experiment, we compared active and passive self-touch to the classical RHI in which the touch is administered by the experimenter. We hypothesized that active self-touch would increase ownership over the virtual hand through the addition of motor signals strengthening the bodily illusion. The results indicated that active self-touch elicited stronger illusory ownership compared to passive self-touch and sensory only stimulation, and show an important role for active self-touch in the formation of bodily self

    Dopamine receptors in GtoPdb v.2023.1

    Get PDF
    Dopamine receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Dopamine Receptors [373]) are commonly divided into D1-like (D1 and D5) and D2-like (D2, D3 and D4) families, where the endogenous agonist is dopamine

    Uptake of Workplace HIV Counselling and Testing: A Cluster-Randomised Trial in Zimbabwe

    Get PDF
    BACKGROUND: HIV counselling and testing is a key component of both HIV care and HIV prevention, but uptake is currently low. We investigated the impact of rapid HIV testing at the workplace on uptake of voluntary counselling and testing (VCT). METHODS AND FINDINGS: The study was a cluster-randomised trial of two VCT strategies, with business occupational health clinics as the unit of randomisation. VCT was directly offered to all employees, followed by 2 y of open access to VCT and basic HIV care. Businesses were randomised to either on-site rapid HIV testing at their occupational clinic (11 businesses) or to vouchers for off-site VCT at a chain of free-standing centres also using rapid tests (11 businesses). Baseline anonymised HIV serology was requested from all employees. HIV prevalence was 19.8% and 18.4%, respectively, at businesses randomised to on-site and off-site VCT. In total, 1,957 of 3,950 employees at clinics randomised to on-site testing had VCT (mean uptake by site 51.1%) compared to 586 of 3,532 employees taking vouchers at clinics randomised to off-site testing (mean uptake by site 19.2%). The risk ratio for on-site VCT compared to voucher uptake was 2.8 (95% confidence interval 1.8 to 3.8) after adjustment for potential confounders. Only 125 employees (mean uptake by site 4.3%) reported using their voucher, so that the true adjusted risk ratio for on-site compared to off-site VCT may have been as high as 12.5 (95% confidence interval 8.2 to 16.8). CONCLUSIONS: High-impact VCT strategies are urgently needed to maximise HIV prevention and access to care in Africa. VCT at the workplace offers the potential for high uptake when offered on-site and linked to basic HIV care. Convenience and accessibility appear to have critical roles in the acceptability of community-based VCT
    corecore