Individual differences among alcohol and tobacco users: Self-classification and problem recognition [abstract]

MU Undergraduate Research Scholars Progra

Do changes in drinking motives mediate the relation between personality change and maturing out of problem drinking?

Recent research has indicated that developmental changes in the personality traits of neuroticism and impulsivity correlate with changes in problem drinking during emerging and young adulthood. However, it remains unclear what potential mechanisms, or mediators, could account for these associations. Drinking motives, particularly drinking to regulate negative affect (drinking to cope) and to get “high” or “drunk” (drinking for enhancement) have been posited to mediate the relationship between personality and drinking problems. Recent work indicates changes in drinking motives parallel changes in alcohol involvement from adolescence to young adulthood. The current study examined changes in drinking motives (i.e., coping and enhancement) as potential mediators of the relation between changes in personality (impulsivity and neuroticism) with changes in alcohol problems in emerging and young adulthood. Analyses were based on data collected from a cohort of college students (N=489) at varying risk for AUDs from ages 18–35. Parallel process latent growth modeling indicated that change in coping (but not enhancement) motives specifically mediated the relation between changes in neuroticism and alcohol problems as well as the relation between changes in impulsivity and alcohol problems. Findings suggest that change in coping motives is an important mechanism in the relation between personality change and the “maturing out” of problematic alcohol involvement

Genetic and environmental influences on impulsivity and coping motives for alcohol across emerging and young adulthood

Variation in the gene encoding the dopamine D4 receptor (DRD4) may moderate the influence of environments (i.e., a gene-environment interaction, GXE) on personality traits and motives associated with alcohol use disorders. This project examines whether variation in DRD4 moderates the environmental influence of childhood adversity on personality (including replication attempts of reported GXE) as well as coping motives. Primary analyses were conducted in the Alcohol, Health, and Behavior (AHB; for current analyses ns=236-252) dataset, a prospective, high-risk sample of college students who were assessed seven times from ages 18-35. Replication analyses were conducted in the Missouri Adolescent Female Twin Study (MOAFTS, for current analyses ns =1,017-1476), a study of a birth cohort of female like-sex twin pairs. Analyses involving DRD4 2- and 5- repeat allele carries vs. others yielded findings inconsistent with the existing GXE personality studies. Although results varied, 7-repeat carriers appeared to be more susceptible to environmental influences on novelty seeking, and to a lesser extent impulsivity, in the AHB data; this finding largely failed to replicate in MOAFTS. No GXE on coping motives were identified. These findings provide limited support that DRD4 status modifies the influence of childhood adversity on personality and have implications for replication-focused research involving GXE

Examination of a Short Version of the UPPS-P Impulsive Behavior Scale

The current study examines a recently developed short version of the UPPS-P Impulsive Behavior Scale. Participants were 251 undergraduate students (59.3% male; mean age = 21.16 ( SD = 4.18); 72% Caucasian). The short version generally replicated the internal consistency (0.74 – 0.88 across subscales) and inter-scale correlations of the full UPPS-P. Moreover, the estimated loss of shared variance was small (0% – 6.4% reductions across subscales) as compared to a 66% time- savings. Structural equation modeling replicated previously supported factor structures and relationships to external outcomes using the full UPPS-P. The short UPPS-P scale should be considered a valid and reliable alternative to the full UPPS-P

Model Convolution: A Computational Approach to Digital Image Interpretation

Digital fluorescence microscopy is commonly used to track individual proteins and their dynamics in living cells. However, extracting molecule-specific information from fluorescence images is often limited by the noise and blur intrinsic to the cell and the imaging system. Here we discuss a method called “model-convolution,” which uses experimentally measured noise and blur to simulate the process of imaging fluorescent proteins whose spatial distribution cannot be resolved. We then compare model-convolution to the more standard approach of experimental deconvolution. In some circumstances, standard experimental deconvolution approaches fail to yield the correct underlying fluorophore distribution. In these situations, model-convolution removes the uncertainty associated with deconvolution and therefore allows direct statistical comparison of experimental and theoretical data. Thus, if there are structural constraints on molecular organization, the model-convolution method better utilizes information gathered via fluorescence microscopy, and naturally integrates experiment and theory

Three low-mass companions around aged stars discovered by TESS

We report the discovery of three transiting low-mass companions to aged stars: a brown dwarf (TOI-2336b) and two objects near the hydrogen burning mass limit (TOI-1608b and TOI-2521b). These three systems were first identified using data from the Transiting Exoplanet Survey Satellite (TESS). TOI-2336b has a radius of $1.05\pm 0.04\ R_J$, a mass of $69.9\pm 2.3\ M_J$ and an orbital period of 7.71 days. TOI-1608b has a radius of $1.21\pm 0.06\ R_J$, a mass of $90.7\pm 3.7\ M_J$ and an orbital period of 2.47 days. TOI-2521b has a radius of $1.01\pm 0.04\ R_J$, a mass of $77.5\pm 3.3\ M_J$ and an orbital period of 5.56 days. We found all these low-mass companions are inflated. We fitted a relation between radius, mass and incident flux using the sample of known transiting brown dwarfs and low-mass M dwarfs. We found a positive correlation between the flux and the radius for brown dwarfs and for low-mass stars that is weaker than the correlation observed for giant planets.Comment: 20 pages, 13 figures; submitted to MNRA

TESS spots a mini-neptune interior to a hot saturn in the TOI-2000 system

Hot jupiters (P 60 $\mathrm{M}_\oplus$) are almost always found alone around their stars, but four out of hundreds known have inner companion planets. These rare companions allow us to constrain the hot jupiter's formation history by ruling out high-eccentricity tidal migration. Less is known about inner companions to hot Saturn-mass planets. We report here the discovery of the TOI-2000 system, which features a hot Saturn-mass planet with a smaller inner companion. The mini-neptune TOI-2000 b ($2.70 \pm 0.15 \,\mathrm{R}_\oplus$, $11.0 \pm 2.4 \,\mathrm{M}_\oplus$) is in a 3.10-day orbit, and the hot saturn TOI-2000 c ($8.14^{+0.31}_{-0.30} \,\mathrm{R}_\oplus$, $81.7^{+4.7}_{-4.6} \,\mathrm{M}_\oplus$) is in a 9.13-day orbit. Both planets transit their host star TOI-2000 (TIC 371188886, V = 10.98, TESS magnitude = 10.36), a metal-rich ([Fe/H] = $0.439^{+0.041}_{-0.043}$) G dwarf 174 pc away. TESS observed the two planets in sectors 9-11 and 36-38, and we followed up with ground-based photometry, spectroscopy, and speckle imaging. Radial velocities from CHIRON, FEROS, and HARPS allowed us to confirm both planets by direct mass measurement. In addition, we demonstrate constraining planetary and stellar parameters with MIST stellar evolutionary tracks through Hamiltonian Monte Carlo under the PyMC framework, achieving higher sampling efficiency and shorter run time compared to traditional Markov chain Monte Carlo. Having the brightest host star in the V band among similar systems, TOI-2000 b and c are superb candidates for atmospheric characterization by the JWST, which can potentially distinguish whether they formed together or TOI-2000 c swept along material during migration to form TOI-2000 b.Comment: v3 adds RV frequency analysis; 25 pages, 11 figures, 14 tables; revision submitted to MNRAS; machine-readable tables available as ancillary files; posterior samples available from Zenodo at https://doi.org/10.5281/zenodo.7683293 and source code at https://doi.org/10.5281/zenodo.798826

Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States

Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, the relative importance of and interactions between these drivers of forest change remain unresolved, particularly over upcoming decades. Here, we assess how the interactive impacts of changing climate and wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset of postfire conifer regeneration from 10,230 field plots. Our findings highlight declining regeneration capacity across the West over the past four decades for the eight dominant conifer species studied. Postfire regeneration is sensitive to high-severity fire, which limits seed availability, and postfire climate, which influences seedling establishment. In the near-term, projected differences in recruitment probability between low- and high-severity fire scenarios were larger than projected climate change impacts for most species, suggesting that reductions in fire severity, and resultant impacts on seed availability, could partially offset expected climate-driven declines in postfire regeneration. Across 40 to 42% of the study area, we project postfire conifer regeneration to be likely following low-severity but not high-severity fire under future climate scenarios (2031 to 2050). However, increasingly warm, dry climate conditions are projected to eventually outweigh the influence of fire severity and seed availability. The percent of the study area considered unlikely to experience conifer regeneration, regardless of fire severity, increased from 5% in 1981 to 2000 to 26 to 31% by mid-century, highlighting a limited time window over which management actions that reduce fire severity may effectively support postfire conifer regeneration. © 2023 the Author(s)