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Emerging evidence suggests regional neuroanatomical variability may be predictive of early alcohol use (before age 15). However, the relationship between whole-brain network organization and early alcohol initiation remains unknown. Using data from the Adolescent Brain Cognitive Development (ABCD) study, we conducted a structural covariance network (SCN) analysis to examine brain network features preceding early alcohol initiation. Structural MRI data collected at baseline (ages 9–10) were used to generate SCNs based on regional cortical thickness measurements. Early alcohol initiation was defined as consuming a full drink between baseline and 4-year follow-up ( ≤ age 15). Participants who reported a full drink of alcohol at baseline, did not participate in the 4-year follow-up, or did not meet imaging quality control criteria were excluded. The remaining participants were compared to a subsample matched at a 1:1 ratio (n = 160 per group). SCN properties, including network segregation (modularity, clustering coefficient), integration (characteristic path length, global efficiency), and resilience (degree assortativity), were compared between groups. While no differences in regional cortical thickness between groups were identified, early initiators demonstrated lower segregation and higher integration compared to non-initiators. These findings suggest that cortical thickness network topology at ages 9–10 may serve as a neuroanatomical risk marker for early adolescent alcohol initiation, independent of prior alcohol exposure, sociodemographic differences, and regional neuroanatomical variability.

The relationship between adolescent alcohol use and emotional problems remains unclear and contradictory. These inconsistencies may in part be due to differences in the measurement and operationalization of alcohol use and emotional problems across studies, as well as confounder selection and missing data decisions. This study explores the associations between common specifications of adolescent alcohol use and emotional problems in a large sample of adolescents. A multiverse analysis (also known as specification curve analysis or vibration of effects) was done with 7680 unique model specifications in a large longitudinal sample of 6639 Australian adolescents (aged ~14.7-15.7, 2021-2022). While alcohol use and emotional problems nearly universally co-occurred in minimally adjusted cross-sectional models (98-99%), the operationalization of emotional problems, temporality of prospective relationships, and choice of confounders substantially impacted findings. Emotional problems appeared to predict later alcohol use more-so than the reverse, depression-focused measures yielded more consistent associations with alcohol use than anxiety-focused measures, and certain confounders (i.e. conduct, ADHD, smoking) explained most of the associations between adolescent alcohol use and emotional problems. Missing data decisions and whether outcomes were modelled continuously dichotomously had minimal impact on findings. While adolescent alcohol use and emotional problems commonly co-occur, inconsistencies in the magnitude, direction, and significance of effects are closely tied to researcher decisions that are often made arbitrarily.

Growing evidence suggests regional and network-level brain imaging features in late childhood are predictive of alcohol use in adolescence. However, the directionality of these effects (i.e. whether they reflect accelerated or delayed neuromaturation) are mixed. We applied a Brain Age Gap Estimation (BrainAGE) model to examine whether overall deviations from typical brain aging trajectories are predictive of (1) alcohol initiation and (2) use behaviour (experimentation versus binge drinking) in adolescence. Data from the Adolescent Brain Cognitive Development study release 6.0 were used. Baseline (ages 9-11) structural imaging features (cortical volume, area, and subcortical volume) were used to estimate BrainAGE. Alcohol use was determined using self-report data from the Substance Use Interview and Timeline Follow-Back across follow-ups (waves 1-6; ages 10-17). Logistic generalized mixed effects models examined whether BrainAGE predicted group status between (1) non-initiators (n=3,639) and initiators (n=1,176), and; (2) experimentation (at least one full drink, no binge episodes; n=461) and binge drinking (at least one episode; n=438). When adjusting for age, sex, and pubertal status, a one-standard-deviation decrease in BrainAGE (equivalent to 1.64 years) at baseline was associated with a 9.5% increase in odds of alcohol initiation in adolescence. However, this effect did not survive adjustment for sociodemographic and prior alcohol exposure covariates. Further, BrainAGE did not discriminate between experimentation and binge drinking. Findings suggest BrainAGE in late childhood may reflect potential risk for alcohol initiation, but not behaviours, in adolescence. However, this association likely reflects complex interactions between brain structure and contextual factors, warranting further investigation.

Early alcohol initiation (before age 15) is associated with adverse outcomes. Understanding mechanisms behind early alcohol initiation is essential for informing prevention efforts. To examine whether structural covariance network properties at ages 9-10 years predict early alcohol initiation. Case-control, population-based study design. Data from the Adolescent Brain Cognitive Development study were used. Baseline structural brain imaging data (ages 9-10) were used for generation and comparison of structural covariance networks. Data from baseline to 4-year follow-up (≤age 15) assessments were used to determine alcohol initiation. Participants were excluded if they reported consuming a full drink of alcohol at baseline, or did not meet imaging inclusion criteria. Controls were excluded if they had not yet been assessed or were missing substance use data at 4-year follow-up. In total, 3,878 participants met study criteria, of which 182 participants initiated alcohol. Structural covariance network properties were compared between the full sample and a 1:1 propensity-matched sample based on age, sex, race, ethnicity, religion, parental education, prenatal alcohol exposure, and baseline alcohol sipping. Structural covariance networks were estimated using regional cortical thickness and volume measurements. Measures of network segregation (modularity, clustering coefficient), integration (characteristic path length, global efficiency), and resilience (degree assortativity) were compared between groups. Early alcohol initiation was defined as consuming a full drink between baseline and 4-year follow-up. Alcohol initiators ( =182, median[IQR] age, 10.3[9.9-10.8]; 101 female[55.5%]) demonstrated lower network segregation (modularity: area-under-the-curve[AUC] difference[95%CI]=-0.017[-0.017,-0.007], =0.030; clustering coefficient: AUC[95%CI]=-0.026[-0.027,-0.012], =0.0495) and higher network integration (characteristic path length: AUC[95%CI]=-0.106[-0.099,-0.046], =0.020; global efficiency: AUC[95%CI]=0.011[0.005,0.011], p=0.010), compared to non-initiators ( =3,696, median[IQR] age, 9.9[9.4-10.4]; 1750 female[47.4%]) when controlling for age, sex, and mean cortical thickness. Within the matched sample, only differences in network integration were preserved (characteristic path length: AUC[95%CI]=-0.044[-0.032,0.035], =0.010; global efficiency: AUC[95%CI]=0.003[-0.003,0.003], =0.040). There were no differences between full or matched samples when comparing cortical volume structural covariance networks. Differences in cortical thickness structural covariance network properties at ages 9-10 predicted alcohol initiation before age 15. These findings suggest cortical thickness network topology may reflect a neuroanatomical risk marker for early alcohol initiation.

We have applied the unsharp-masking technique to the 24 μm image of the SMC, obtained with the Spitzer, to search for high-extinction regions. Fifty-five candidate regions of high-extincion (namely high-contrast regions, HCRs) have been identified from the decremental contrast image. HCRs have a size of 8 - 14 pc and a peak contrast at 24 μm of 2 - 2.5%. To constrain physical properties of HCRs, we have performed observations of NH3, N2H+, HNC, HCO+, and HCN toward one of the HCRs, HCR LIRS36–east, using the ATCA and the Mopra telescope. No molecular line emission detected, but upper limits to column densities of molecular species suggest that HCRs are moderately dense with n ~ 103 cm−3. Two interesting properties of HCRs are shown below.

We present Very Large Array observations of ammonia (NH3) (1,1), (2,2), and CCS (2_1-1_0) emission toward the Infrared Dark Cloud (IRDC) G19.30+0.07 at ~22GHz. The NH3 emission closely follows the 8 micron extinction. The NH3 (1,1) and (2,2) lines provide diagnostics of the temperature and density structure within the IRDC, with typical rotation temperatures of ~10 to 20K and NH3 column densities of ~10^15 cm^-2. The estimated total mass of G19.30+0.07 is ~1130 Msun. The cloud comprises four compact NH3 clumps of mass ~30 to 160 Msun. Two coincide with 24 micron emission, indicating heating by protostars, and show evidence of outflow in the NH3 emission. We report a water maser associated with a third clump; the fourth clump is apparently starless. A non-detection of 8.4GHz emission suggests that the IRDC contains no bright HII regions, and places a limit on the spectral type of an embedded ZAMS star to early-B or later. From the NH3 emission we find G19.30+0.07 is composed of three distinct velocity components, or \"subclouds.\" One velocity component contains the two 24 micron sources and the starless clump, another contains the clump with the water maser, while the third velocity component is diffuse, with no significant high-density peaks. The spatial distribution of NH3 and CCS emission from G19.30+0.07 is highly anti-correlated, with the NH3 predominantly in the high-density clumps, and the CCS tracing lower-density envelopes around those clumps. This spatial distribution is consistent with theories of evolution for chemically young low-mass cores, in which CCS has not yet been processed to other species and/or depleted in high-density regions.

We report VLBA observations of maser emission from the rotationally excited doublet Pi 1/2, J=1/2 state of OH at 4765 MHz. We made phase-referenced observations of W3(OH) at both 4765 MHz and 1720 MHz and found emission in three fields within a about 2000 AU diameter region and verified that in two of the three fields, 4765 MHz and 1720 MHz emission arise from the same position to within about 4 mas (about 5 AU diameter emission regions along an approximately N-S arc with linear extent about 500 AU. In addition, we carried out phase-referenced observations of 4765 MHz emission from K3-50. We searched for the 4765 MHz line in W49 (without phase referencing) and W75N (phase-referenced to the strongest 4765 MHz maser feature in DR21EX); we were unable to detect these sources with the VLBA. For 2 1/2 years (including the dates of the VLBA observations), we carried out monitoring observations of 4765 MHz emission with the VLA. Constraints on models for maser emission at 1720 MHz and 4765 MHz are derived from the observations. These observations are then briefly compared with existing models.

We report here the discovery of a significant source of systematic error in the rotation measure determinations of pulsars. Conventional analysis of high sensitivity polarimetric observations of PSR B2016+28 display variation of the rotation measure of \\(\\pm\\)15 rad m\\(^{-2}\\) (around the mean value of -34.6 rad m\\(^{-2}\\)) across the pulse profile. Analysis of single pulse data shows that this variation is an artifact of the incoherent superposition of quasi-orthogonal polarisation modes along with the frequency dependence of relative strength and/or quasi-orthogonality of the modes. Quasi-orthogonal polarization is common among pulsars, and therefore this effect needs to be taken into account in the interpretation of pulsar rotation measures.

We report on preliminary results from the recent multi-epoch neutral hydrogen absorption measurements toward three pulsars, B0823+26, B1133+16 and B2016+28, using the Arecibo telescope. We do not find significant variations in optical depth profiles over periods of 0.3 and 9--10 yr, or on spatial scales of 10--20 and 70--85 AU. The large number of non detections of the tiny scale atomic structure suggests that the AU-sized structure is not ubiquitous in the interstellar medium and could be quite a rare phenomenon.

We have measured Faraday Rotation Measures (RMs) at Arecibo Observatory for 36 pulsars, 17 of them new. We combine these and earlier measurements to study the galactic magnetic field and its possible temporal variations. Many RM values have changed significantly on several-year timescales, but these variations probably do not reflect interstellar magnetic field changes. By studying the distribution of pulsar RMs near the plane in conjunction with the new NE2001 electron density model, we note the following structures in the first galactic longitude quadrant: (1) The local field reversal can be traced as a null in RM in a 0.5-kpc wide strip interior to the Solar Circle, extending \\~7 kpc around the Galaxy. (2) Steadily increasing RMs in a 1-kpc wide strip interior to the local field reversal, and also in the wedge bounded by 42

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