Dark halos acting as chaos controllers in asymmetric triaxial galaxy models

We study the regular or chaotic character of orbits in a 3D dynamical model, describing a triaxial galaxy surrounded by a spherical dark halo component. Our numerical experiments suggest that the percentage of chaotic orbits decreases exponentially as the mass of the dark halo increases. A linear increase of the percentage of the chaotic orbits was observed as the scale length of the halo component increases. In order to distinguish between regular and chaotic motion, we chose to use the total angular momentum Ltot of the 3D orbits as a new indicator. Comparison with other, previously used, dynamical indicators, such as the Lyapunov Characteristic Exponent or the P(f) spectral method, shows that the Ltot indicator gives very fast and reliable results for characterizing the nature of orbits in galactic dynamical models.Comment: Published in Research in Astronomy and Astrophysics (RAA) journa

Do facial first impressions reflect a shared social reality?

This work was supported by an Australian Research Council (ARC) Discovery Early Career Research Award to CS [DE 190101043], the ARC Centre of Excellence in Cognition and its Disorders [CE110001021], and an ARC Discovery Award [DP170104602]. The funding sources had no influence on the research.Peer reviewedPostprintPostprin

Archeological and Bioarcheological Investigations at Campbell’s Bayou Cemetery Galveston County, Texas

This report documents the removal of individuals buried within Campbell’s Bayou Cemetery (41GV171) to avoid potential impact to the remains during implementation of remediation activities at the Malone Service Company Superfund Site (Site) in Texas City, TX. An oil recovery and waste processing facility had operated at the Site for more than 30 years, ending in the mid1990s. The facility had stored, processed, and disposed of industrial solid wastes and hazardous wastes. In July 2012, a group of companies known as the Malone Cooperating Parties (MCP) entered into a Consent Decree with the U.S. Government, the U.S. Environmental Protection Agency, and the State of Texas to implement a remedial design and remedial action at the Site. It was determined that if the remains in the cemetery were not relocated, there was the potential that remediation activities could impact the cemetery. Archival research, review of historic maps and aerial photographs, and reconnaissance survey revealed the extent of potential remains at the cemetery, and, given the location of the cemetery and the scope of the planned remediation activities, it was deemed impractical for the environmental remediation contractors to work around the cemetery. (41GV171). The MCP consulted with EPA, Campbell family descendants, the Galveston County Historical Commission, and the Texas Historical Commission and developed a plan to relocate the remains to a perpetual care cemetery in accordance with Texas state law and associated rules and procedures. In accordance with Texas Health and Safety Code §711.004, the landowner Land Navigator, Ltd., on behalf of the MCP, petitioned the Galveston County Judicial District Court for removal of the dedication of the cemetery and the transfer of the human remains to the perpetual care cemetery operated by Forest Park East Funeral Home and Cemetery (FPE), 21620 Gulf Freeway, Webster, TX 77598. On February 11, 2014, Land Navigator was granted a Summary Judgment allowing Land Navigator to disinter and relocate the remains to FPE. Versar, Inc. (formerly Geo-Marine, Inc.), on behalf of the MCP, provided all archeological and human osteological expertise for the disinterment and analysis of the human remains. Disinterment permits from the State Registrar of the Vital Statistics Unit of the Department of State Health Services, as required by Texas Administrative Code, Title 13, Chapter 22 (Texas Historical Commission, Cemeteries), were obtained for each burial. The disinterment excavations at Campbell’s Bayou Cemetery revealed 34 burials from which 35 individuals were excavated. No graves were marked by headstones. It is the professional judgment of Versar that, of the 35 individual sets of remains identified, 11 were determined to be adults (5 male and 3 female; 3 of indeterminate sex), and 24 were determined to be children. The majority of children at Campbell’s Bayou Cemetery (n=18) are under 5 years of age and six are premature infants aged 30–40 weeks. Burials could not be associated conclusively with any individuals identified by the descendants; however, the combination of bioarcheological analysis, coffin hardware analysis, census data, and descendant identifications resulted in a list of individuals that may have been interred in certain graves. Some of the interments include James and Mary Campbell, Charlie Meyers, Benjamin Ninnie Dick, Phoebe Rutlage, and Shelby McNeil, Jr. Children were difficult to identify; however, there is good potential the graves of Frank Campbell, Mary Jane Campbell, Charles Munson, and Grace Dick were identified. Data are conclusive that the children Levi and Joseph (Joe) Parr were both interred together in Burial 6, the concrete crypt with brick covering. Grace Dick was the last individual interred at the cemetery in 1904

The Metagalactic Ionizing Radiation Field at Low Redshift

We compute the ionizing radiation field at low redshift, arising from Seyferts, QSOs, and starburst galaxies. This calculation combines recent Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN database, and a new intergalactic opacity model based on Hubble Space Telescope and Keck Ly-alpha absorber surveys. At z = 0 for AGN only, our best estimate for the specific intensity at 1 Ryd is I_0 = 1.3 (+0.8/-0.5) x 10^-23 ergs/cm^2/s/Hz/sr, independent of H_0, Omega_0, and Lambda. The one-sided ionizing photon flux is Phi_ion = 3400 (+2100/-1300) photons/cm^2/s, and the H I photoionization rate is Gamma_HI = 3.2 (+2.0/-1.2) x 10^-14 s^-1 for alpha_s = 1.8. We also derive Gamma_ HI for z = 0 - 4. These error ranges reflect uncertainties in the spectral indexes for the ionizing EUV (alpha_s = 1.8 +/- 0.3) and the optical/UV (alpha_UV = 0.86 +/- 0.05), the IGM opacity model, the range of Seyfert luminosities (0.001 - 100 L*) and the completeness of the luminosity functions. Our estimate is a factor of three lower than the most stringent upper limits on the ionizing background (Phi_ion < 10^4 photons/cm^2/s) obtained from H-alpha observations in external clouds, and it lies within the range implied by other indirect measures. Starburst galaxies with a sufficiently large Lyman continuum escape fraction, f_ esc > 0.05, may provide a comparable background to AGN, I_0 (z=0) = 1.1 (+1.5/-0.7) x 10^{-23). An additional component of the ionizing background of this magnitude would violate neither upper limits from H-alpha observations nor the acceptable range from other measurements.Comment: 30 pages, 9 figures, accepted for Astronomical J. (Oct. 1999

Examining the bidirectional association between emotion recognition and social autistic traits using observational and genetic analyses

Background: There is mixed evidence for an association between autism spectrum disorder (ASD) and emotion recognition deficits. We sought to assess the bidirectionality of this association using phenotypic and genetic data in a large community sample. Methods: Analyses were conducted in three stages. First, we examined the bidirectional association between social autistic traits at age 8 years and emotion recognition task (ERT) responses at age 24 years (Study 1; N = 3,562); and between Diagnostic Analysis of Non-Verbal Accuracy (DANVA) emotion recognition responses at age 8 years and social autistic traits at age 10 years (Study 2; N = 9,071). Next, we used genetic analyses (Study 3) to examine the association between polygenic risk scores for ASD and outcomes for the ERT and DANVA. The genetic correlation between ASD and ERT responses at age 24 was also estimated. Analyses were conducted in the Avon Longitudinal Study of Parents and Children. Results: Social autistic traits at age 8 years were negatively associated with later total correct responses on ERT in Study 1 (b = −0.18; 95% CI: −0.27 to −0.09). We also found evidence of an association in Study 2 (b = −0.04; 95% CI: −0.05 to −0.03). We found the opposite association, that is positive, between the ASD polygenic risk score and ERT (b = 0.40; 95% CI: 0.10 to 0.70); however, this association varied across different p-value thresholds and would not survive multiple testing, so should be interpreted with caution. We did not find evidence of a genetic correlation between ASD and ERT. Conclusion: We found an observational association between poorer emotion recognition and increased social autistic traits. Our genetic analyses may suggest a shared genetic aetiology between these or a potential causal pathway; however, future research would benefit from using better powered GWAS to examine this further. Our results may inform interventions targeting emotion recognition

The effects of age at menarche and first sexual intercourse on reproductive and behavioural outcomes:A Mendelian randomization study

There is substantial variation in the timing of significant reproductive life events such as menarche and first sexual intercourse. Life history theory explains this variation as an adaptive response to an individual's environment and it is important to examine how traits within life history strategies affect each other. Here we applied Mendelian randomization (MR) methods to investigate whether there is a causal effect of variation in age at menarche and age at first sexual intercourse (markers or results of exposure to early life adversity) on outcomes related to reproduction, education and risky behaviour in UK Biobank (N = 114 883-181 255). Our results suggest that earlier age at menarche affects some traits that characterize life history strategies including earlier age at first and last birth, decreased educational attainment, and decreased age at leaving education (for example, we found evidence for a 0.26 year decrease in age at first birth per year decrease in age at menarche, 95% confidence interval: -0.34 to -0.17; p < 0.001). We find no clear evidence of effects of age at menarche on other outcomes, such as risk taking behaviour. Age at first sexual intercourse was also related to many life history outcomes, although there was evidence of horizontal pleiotropy which violates an assumption of MR and we therefore cannot infer causality from this analysis. Taken together, these results highlight how MR can be applied to test predictions of life history theory and to better understand determinants of health and social behaviour

Metal Abundances in the Magellanic Stream

We report on the first metallicity determination for gas in the Magellanic Stream, using archival HST GHRS data for the background targets Fairall 9, III Zw 2, and NGC 7469. For Fairall 9, using two subsequent HST revisits and new Parkes Multibeam Narrowband observations, we have unequivocally detected the MSI HI component of the Stream (near its head) in SII1250,1253 yielding a metallicity of [SII/H]=-0.55+/-0.06(r)+/-0.2(s), consistent with either an SMC or LMC origin and with the earlier upper limit set by Lu et al. (1994). We also detect the saturated SiII1260 line, but set only a lower limit of [SiII/H]>-1.5. We present serendipitous detections of the Stream, seen in MgII2796,2803 absorption with column densities of (0.5-1)x10^13 cm^-2 toward the Seyfert galaxies III Zw 2 and NGC 7469. These latter sightlines probe gas near the tip of the Stream (80 deg down-Stream of Fairall 9). For III Zw 2, the lack of an accurate HI column density and the uncertain MgIII ionization correction limits the degree to which we can constrain [Mg/H]; a lower limit of [MgII/HI]>-1.3 was found. For NGC 7469, an accurate HI column density determination exists, but the extant FOS spectrum limits the quality of the MgII column density determination, and we conclude that [MgII/HI]>-1.5. Ionization corrections associated with MgIII and HII suggest that the corresponding [Mg/H] may range lower by 0.3-1.0 dex. However, an upward revision of 0.5-1.0 dex would be expected under the assumption that the Stream exhibits a dust depletion pattern similar to that seen in the Magellanic Clouds. Remaining uncertainties do not allow us to differentiate between an LMC versus SMC origin to the Stream gas.Comment: 30 pages, 8 figures, LaTeX (aaspp4), also available at http://casa.colorado.edu/~bgibson/publications.html, accepted for publication in The Astronomical Journa

The Cosmic Ultraviolet Baryon Survey (CUBS) I. Overview and the diverse environments of Lyman limit systems at z<1

We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z<~1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman Limit Systems (LLSs) at zabs~ 17.2 over a total redshift survey pathlength of dz=9.3, and a number density of n(z)=0.43 (-0.18, +0.26). Considering all absorbers with log N(HI)/cm^-2 > 16.5 leads to n(z)=1.08 (-0.25, +0.31) at z<1. All LLSs exhibit a multi-component structure and associated metal transitions from multiple ionization states such as CII, CIII, MgII, SiII, SiIII, and OVI absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than 0.1L* at d<~300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disk, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d=15 to 72 pkpc and intrinsic luminosities from ~0.01L* to ~3L*. Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities.Comment: 26 pages, 14 figures, MNRAS in pres

Does repeatedly viewing overweight versus underweight images change perception of and satisfaction with own body size?

Body dissatisfaction is associated with subsequent eating disorders and weight gain. One-off exposure to bodies of different sizes changes perception of others' bodies, and perception of and satisfaction with own body size. The effect of repeated exposure to bodies of different sizes has not been assessed. We randomized women into three groups, and they spent 5 min twice a day for a week completing a one-back task using images of women modified to appear either under, over, or neither over- nor underweight. We tested the effects on their perception of their own and others' body size, and satisfaction with own size. Measures at follow-up were compared between groups, adjusted for baseline measurements. In 93 women aged 18–30 years, images of other women were perceived as larger following exposure to underweight women (and vice versa) (p < 0.001). There was no evidence for a difference in our primary outcome measure (visual analogue scale own size) or in satisfaction with own size. Avatar-constructed ideal (p = 0.03) and avatar-constructed perceived own body size (p = 0.007) both decreased following exposure to underweight women, possibly due to adaptation affecting how the avatar was perceived. Repeated exposure to different sized bodies changes perception of the size of others' bodies, but we did not find evidence that it changes perceived own size