1,265 research outputs found
The ionizing sources of luminous compact HII regions in the RCW106 and RCW122 clouds
Given the rarity of young O star candidates, compact HII regions embedded in
dense molecular cores continue to serve as potential sites to peer into the
details of high-mass star formation. To uncover the ionizing sources of the
most luminous and compact HII regions embedded in the RCW106 and RCW122 giant
molecular clouds, known to be relatively nearby (2-4 kpc) and isolated, thus
providing an opportunity to examine spatial scales of a few hundred to a
thousand AU in size. High spatial resolution (0.3"), mid-infrared spectra
(R=350), including the fine structure lines [ArIII] and [NeII], were obtained
for four luminous compact HII regions, embedded inside the dense cores within
the RCW106 and RCW122 molecular cloud complexes. At this resolution, these
targets reveal point-like sources surrounded by nebulosity of different
morphologies, uncovering details at spatial dimensions of <1000AU. The
point-like sources display [ArIII] and [NeII] lines - the ratios of which are
used to estimate the temperature of the embedded sources. The derived
temperatures are indicative of mid-late O type objects for all the sources with
[ArIII] emission. Previously known characteristics of these targets from the
literature, including evidence of disk or accretion suggest that the identified
sources may grow more to become early-type O stars by the end of the star
formation process
The effect of the Müller-Lyer illusion on saccades is modulated by spatial predictability and saccadic latency
Studies investigating the effect of visual illusions on saccadic eye movements have provided a wide variety of results. In this study, we test three factors that might explain this variability: the spatial predictability of the stimulus, the duration of the stimulus and the latency of the saccades. Participants made a saccade from one end of a Müller-Lyer figure to the other end. By changing the spatial predictability of the stimulus, we find that the illusion has a clear effect on saccades (16%) when the stimulus is at a highly predictable location. Even stronger effects of the illusion are found when the stimulus location becomes more unpredictable (19–23%). Conversely, manipulating the duration of the stimulus fails to reveal a clear difference in illusion effect. Finally, by computing the illusion effect for different saccadic latencies, we find a maximum illusion effect (about 30%) for very short latencies, which decreases by 7% with every 100 ms latency increase. We conclude that spatial predictability of the stimulus and saccadic latency influences the effect of the Müller-Lyer illusion on saccades
The social determinants of polymorphous prejudice against lesbian and gay individuals: the case of Portugal
In the present article, we analyze polymorphous prejudice against lesbians and gays according to a sample of Portuguese heterosexual individuals. We tested the differential importance of demographic-, ideological-, and psychological-level variables to predicting this phenomenon. Our results show that male, Catholic, right-wing respondents with fewer lesbian and gay (LG) friends prove the group exhibiting the highest levels of polymorphous prejudice. Furthermore, the introduction of psychological-level variables into the regression models increased the explained variance in polymorphous prejudice, above and beyond the remaining predictors. Additionally, we report different patterns of results when deploying regression analyses at the level of the sub-scales of polymorphous prejudice. We discuss our results within the light of contemporary sexual prejudice frameworks before reviewing the utility of results to interventions targeting discriminated LG individuals.info:eu-repo/semantics/acceptedVersio
The spin temperature of high-redshift damped Lyman- systems
We report results from a programme aimed at investigating the temperature of
neutral gas in high-redshift damped Lyman- absorbers (DLAs). This
involved (1) HI 21cm absorption studies of a large DLA sample, (2) VLBI studies
to measure the low-frequency quasar core fractions, and (3) optical/ultraviolet
spectroscopy to determine DLA metallicities and velocity widths.
Including literature data, our sample consists of 37 DLAs with estimates of
the spin temperature and the covering factor. We find a strong )
difference between the distributions in high-z (z>2.4) and low-z (z<2.4)
DLA samples. The high-z sample contains more systems with high values,
K. The distributions in DLAs and the Galaxy are also
clearly (~) different, with more high- sightlines in DLAs than in
the Milky Way. The high values in the high-z DLAs of our sample arise due
to low fractions of the cold neutral medium.
For 29 DLAs with metallicity [Z/H] estimates, we confirm the presence of an
anti-correlation between and [Z/H], at significance via a
non-parametric Kendall-tau test. This result was obtained with the assumption
that the DLA covering factor is equal to the core fraction. Monte Carlo
simulations show that the significance of the result is only marginally
decreased if the covering factor and the core fraction are uncorrelated, or if
there is a random error in the inferred covering factor.
We also find evidence for redshift evolution in DLA values even for the
z>1 sub-sample. Since z>1 DLAs have angular diameter distances comparable to or
larger than those of the background quasars, they have similar efficiency in
covering the quasars. Low covering factors in high-z DLAs thus cannot account
for the observed redshift evolution in spin temperatures. (Abstract abridged.)Comment: 37 pages, 22 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Atyidae and Palaemonidae (Crustacea: Decapoda: Caridea) of Bocas del Toro, Panama.
The present contribution is a preliminary report on the freshwater caridean fauna of Bocas del Toro province, northeastern Panama, based on field collections carried out during a Shrimp Taxonomy Workshop at the STRI station in Bocas del Toro in August 2008. A total of eight species from two families, Atyidae and Palaemonidae, were collected at 17 different collection sites in the rivers, streams and ponds on several islands of the Bocas del Toro archipelago and the adjacent mainland. The species reported herein are Atya scabra (Leach, 1815), Jonga serrei (Bouvier, 1909), Micratya poeyi (Guérin-Méneville, 1855), Potimirim glabra (Kingsley, 1878), P. potimirim (Müller, 1881) (Atyidae), Palaemon pandaliformis (Stimpson, 1871), Macrobrachium acanthurus (Wiegmann, 1836) and M. crenulatum Holthuis, 1950 (Palaemonidae). The record of J. serrei is the first for Panama, and M. poeyi a P. glabra the first for Bocas del Toro province
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