5,279 research outputs found

    Perceiver Effects as Projective Tests: What Your Perceptions of Others Say about You

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    In three studies, we document various properties of perceiver effects—or how an individual generally tends to describe other people in a population. First, we document that perceiver effects have consistent relationships with dispositional characteristics of the perceiver, ranging from self-reported personality traits and academic performance to well-being and measures of personality disorders, to how liked the person is by peers. Second, we document that the covariation in perceiver effects among trait dimensions can be adequately captured by a single factor consisting of how positively others are seen across a wide range of traits (e.g., how nice, interesting, trustworthy, happy, and stable others are generally seen). Third, we estimate the one-year stability of perceiver effects and show that individual differences in the typical perception of others have a level of stability comparable to that of personality traits. The results provide compelling evidence that how individuals generally perceive others is a stable individual difference that reveals much about the perceiver’s own personality

    Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

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    We have carried out a search for optically visible post-asymptotic giant branch (post-AGB) stars in the Large Magellanic Cloud (LMC). First, we selected candidates with a mid-IR excess and then obtained their optical spectra. We disentangled contaminants with unique spectra such as M stars, C stars, planetary nebulae, quasi-stellar objects and background galaxies. Subsequently, we performed a detailed spectroscopic analysis of the remaining candidates to estimate their stellar parameters such as effective temperature, surface gravity (log g), metallicity ([Fe/H]), reddening and their luminosities. This resulted in a sample of 35 likely post-AGB candidates with late-G to late-A spectral types, low log g, and [Fe/H] < -0.5. Furthermore, our study confirmed the existence of the dusty post-red giant branch (post-RGB) stars, discovered previously in our Small Magellanic Cloud survey, by revealing 119 such objects in the LMC. These objects have mid-IR excesses and stellar parameters (Teff, log g, [Fe/H]) similar to those of post-AGB stars except that their luminosities (< 2500 L&sun;), and hence masses and radii, are lower. These post-RGB stars are likely to be products of binary interaction on the RGB. The post-AGB and post-RGB objects show spectral energy distribution properties similar to the Galactic post-AGB stars, where some have a surrounding circumstellar shell, while some others have a surrounding stable disc similar to the Galactic post-AGB binaries. This study also resulted in a new sample of 162 young stellar objects, identified based on a robust log g criterion. Other interesting outcomes include objects with an UV continuum and an emission line spectrum; luminous supergiants; hot main-sequence stars; and 15 B[e] star candidates, 12 of which are newly discovered in this study

    How Functionalist and Process Approaches to Behavior Can Explain Trait Covariation

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    Factors identified in investigations of trait structure (e.g., the Big Five) are sometimes understood as explanations or sources of the covariation of distinct behavioral traits, as when extraversion is suggested to underlie the covariation of assertiveness and sociability. Here, we detail how trait covariation can alternatively be understood as arising from units common to functionalist and process frameworks, such as self-efficacies, expectancies, values, and goals. Specifically, the expected covariation between two behavioral traits should be increased when a specific process variable tends to indicate the functionality of both traits simultaneously. In 2 empirical illustrations, we identify a wide array of specific process variables associated with several Big Five-related behavioral traits simultaneously, and which are thus likely sources of their covariation. Many of these, such as positive interpersonal expectancies, self-regulatory skills, and preference for order, relate similarly to a broad range of trait perceptions in both studies, and across both self- and peer-reports. We also illustrate how this understanding of trait covariation provides a somewhat novel explanation of why some traits are uncorrelated. As we discuss, a functionalist understanding of trait covariation as arising through functionalist or process variables has implications for many basic issues in personality psychology, such as how personality traits should be measured, mechanisms for personality stability and change, and the nature of personality traits more generally. Includes supplementary materials

    Chemical abundance study of two strongly s-process enriched post-AGB stars in the LMC: J051213.81-693537.1 and J051848.86-700246.9

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    Context. This paper is part of a larger project in which we systematically study the chemical abundances of extra-galactic post-asymptotic giant branch (post-AGB) stars. The aim of our programme is to derive chemical abundances of stars covering a large range in luminosity and metallicity with the ultimate goal of testing, constraining, and improving our knowledge of the poorly understood AGB phase, especially the third dredge-up mixing processes and associated s-process nucleosynthesis. Aims. Post-AGB photospheres are dominated by atomic lines and indicate the effects of internal chemical enrichment processes over the entire stellar lifetime. In this paper, we study two carefully selected post-AGB stars: J051213.81-693537.1 and J051848.86-700246.9 in the Large Magellanic Cloud (LMC). Both objects show signs of s-process enhancement. The combination of favourable atmospheric parameters for detailed abundance studies and their known distances (and hence luminosities and initial masses) make these objects ideal probes of the AGB third dredge-up and s-process nucleosynthesis in that they provide observational constraints for theoretical AGB models. Methods. We use high-resolution optical UVES spectra to determine accurate stellar parameters and subsequently perform detailed elemental abundance studies of post-AGB stars. Additionally, we use available photometric data covering optical and IR bands to construct spectral energy distributions for reddening and luminosity determinations. We then estimate initial masses from theoretical post-AGB tracks. Results. We obtained accurate atmospheric parameters for J051213.81-693537.1 (Teff = 5875 ± 125 K, log g = 1.00 ± 0.25 dex, [Fe/H] = -0.56 ± 0.16 dex) and J051848.86-700246.9 (Teff = 6000 ± 125 K, log g = 0.50 ± 0.25 dex, [Fe/H] = -1.06 ± 0.17 dex). Both stars show extreme s-process enrichment associated with relatively low C/O ratios of 1.26 ± 0.40 and 1.29 ± 0.30 for J051213-693537.1 and J051848-700246.9, respectively. We could only derive upper limits of the lead (Pb) abundance. These upper limits show a possible very slight Pb overabundance with respect to heavy s-elements for J051213-693537.1, while J051848-700246.9 shows an upper limit of the Pb abundance similar to [hs/Fe]. A comparison with theoretical post-AGB evolutionary tracks in the HR-diagram reveals that both stars have low initial masses between 1.0 and 1.5 Mo. Conclusions. This study adds to the results obtained so far on a very limited number of s-process enriched stars in the Magellanic Clouds. With the addition of the two stars in this study, we find an increasing discrepancy between observed and predicted Pb abundances towards lower metallicities of the studied s-process rich post-AGB stars in the Magellanic Clouds. The more metal-rich J051213-693537.1 fits the theoretical Pb abundance predictions well, while the five other objects with [Fe/H] < 1, including J051848-700246.9, have much lower Pb overabundances than predicted. In all objects found so far, including the objects in this study, the C/O ratio is very moderate because of the enhancement of O as well as C. We find that all s-process rich stars in the LMC and SMC studied so far, cluster in the same region of the HR-diagram and are associated with low-mass stars with a low metallicity on average. We corroborate the published lack of correlation between the metallicity and the neutron irradiation, while the neutron exposure ([hs/ls]) is strongly correlated with the third dredge-up efficiency ([s/Fe]). These correlations seem to hold in our Galaxy as well as in the Magellanic Clouds

    Evidence for Placental HPV Infection in Both HIV Positive and Negative Women

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    Human papillomaviruses (HPVs) have previously been reported to infect epithelial trophoblast cells of the placenta. To investigate this possibility, 200 placental samples from Zambian women were separated into HIV+ and HIV− groups and tested for HPV by redundant primer PCR, using GP5+/GP6+ and CPI/CPII primer sets. Three HPV genotypes (HPV6, 16 and 90) were detected in placental samples. Whereas, 20 different HPV genotypes were detected in vaginal sampling of the same patients, suggesting that compartment specific sub-populations of HPV may exist. The incidence of HPV16 in placental samples was almost 2-fold greater in HIV+ women compared to HIV− (p = 0.0241). HPV16 L1 expression, detected by immunochemistry, was significantly higher in HIV+ than HIV− samples (p = 0.0231). HPV16 DNA was detected in the nuclei of trophoblast cells by in situ hybridization. Overall, these results suggest that HPVs infect the placenta and that HIV significantly influences these infections
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