Ro-vibrational Spectroscopy of CI Tau -- Evidence of a Multi-Component Eccentric Disk Induced by a Planet

CI Tau is currently the only T Tauri star with an inner protoplanetary disk that hosts a planet, CI Tau b, that has been detected by a radial velocity survey. This provides the unique opportunity to study disk features that were imprinted by that planet. We present multi-epoch spectroscopic data, taken with NASA IRTF in 2022, of the ${}^{12}$CO and hydrogen Pf$\beta$ line emissions spanning 9 consecutive nights, which is the proposed orbital period of CI Tau b. We find that the star's accretion rate varied according to that 9~d period, indicative of companion driven accretion. Analysis of the ${}^{12}$CO emission lines reveals that the disk can be described with an inner and outer component spanning orbital radii 0.05-0.13~au and 0.15-1.5~au, respectively. Both components have eccentricities of about 0.05 and arguments of periapses that are oppositely aligned. We present a proof-of-concept hydrodynamic simulation that shows a massive companion on a similarly eccentric orbit can recreate a similar disk structure. Our results allude to such a companion being located around an orbital distance of 0.14~au. However, this planet's orbital parameters may be inconsistent with those of CI Tau b whose high eccentricity is likely not compatible with the low disk eccentricities inferred by our model.Comment: Accepted to A

Driving performance in older adults: Current measures, findings, and implications for roadway safety

BACKGROUND AND OBJECTIVES: Over 10,000 people a day turn 65 in the United States. For many older adults, driving represents an essential component of independence and is one of the most important factors in overall mobility. Recent survey studies in older adults suggest that up to 60% of older adult drivers with mild cognitive impairment, and up to 30% with dementia, continue to drive. The purpose of this review is to provide a comprehensive and detailed resource on the topics of cognition and driving for clinicians, researchers, and policymakers working on efforts related to older adult drivers. RESEARCH DESIGN AND METHODS: Publications on PubMed and Medline and discussions with experts working in geriatrics, technology, driving policy, psychology, and diverse aspects of driving performance were utilized to inform the current review. RESULTS: Research indicates that there is a complex and inverse correlation between multiple cognitive measures, driving performance, and risky driving behaviors. The fragmented nature of available peer-reviewed literature, and a reliance on correlative data, do not currently allow for the identification of the temporal and reciprocal nature of the interplay between cognition and driving endpoints. DISCUSSION AND IMPLICATIONS: There are currently no widely accepted definitions, conceptual models, or uniform set of analyses for conducting geriatric research that is focused on driving. Establishing conventions for conducting research that harmonizes the fields of geriatrics, cognition, and driving research is critical for the development of the evidence base that will inform clinical practice and road safety policy

Anomalous metamagnetism in the low carrier density Kondo lattice YbRh3Si7

We report complex metamagnetic transitions in single crystals of the new low carrier Kondo antiferromagnet YbRh3Si7. Electrical transport, magnetization, and specific heat measurements reveal antiferromagnetic order at T_N = 7.5 K. Neutron diffraction measurements show that the magnetic ground state of YbRh3Si7 is a collinear antiferromagnet where the moments are aligned in the ab plane. With such an ordered state, no metamagnetic transitions are expected when a magnetic field is applied along the c axis. It is therefore surprising that high field magnetization, torque, and resistivity measurements with H||c reveal two metamagnetic transitions at mu_0H_1 = 6.7 T and mu_0H_2 = 21 T. When the field is tilted away from the c axis, towards the ab plane, both metamagnetic transitions are shifted to higher fields. The first metamagnetic transition leads to an abrupt increase in the electrical resistivity, while the second transition is accompanied by a dramatic reduction in the electrical resistivity. Thus, the magnetic and electronic degrees of freedom in YbRh3Si7 are strongly coupled. We discuss the origin of the anomalous metamagnetism and conclude that it is related to competition between crystal electric field anisotropy and anisotropic exchange interactions.Comment: 23 pages and 4 figures in the main text. 7 pages and 5 figures in the supplementary materia

Twentyâ fiveâ year trajectories of insulin resistance and pancreatic βâ cell response and diabetes risk in nonalcoholic fatty liver disease

Background & AimsInsulin resistance is a risk marker for nonâ alcoholic fatty liver disease, and a risk factor for liver disease progression. We assessed temporal trajectories of insulin resistance and βâ cell response to serum glucose concentration throughout adulthood and their association with diabetes risk in nonâ alcoholic fatty liver disease.MethodsThree thousand and sixty participants from Coronary Artery Risk Development in Young Adults, a prospective biâ racial cohort of adults age 18â 30 years at baseline (1985â 1986; Y0) who completed up to 5 exams over 25 years and had fasting insulin and glucose measurement were included. At Y25 (2010â 2011), nonâ alcoholic fatty liver disease was assessed by noncontrast computed tomography after exclusion of other liver fat causes. Latent mixture modelling identified 25â year trajectories in homeostatic model assessment insulin resistance and βâ cell response homeostatic model assessmentâ β.ResultsThree distinct trajectories were identified, separately, for homeostatic model assessment insulin resistance (lowâ stable [47%]; moderateâ increasing [42%]; and highâ increasing [12%]) and homeostatic model assessmentâ β (lowâ decreasing [16%]; moderateâ decreasing [63%]; and highâ decreasing [21%]). Y25 nonâ alcoholic fatty liver disease prevalence was 24.5%. Among nonâ alcoholic fatty liver disease, highâ increasing homeostatic model assessment insulin resistance (referent: lowâ stable) was associated with greater prevalent (OR 95% CI = 8.0, 2.0â 31.9) and incident (OR = 10.5, 2.6â 32.8) diabetes after multivariable adjustment including Y0 or Y25 homeostatic model assessment insulin resistance. In contrast, nonâ alcoholic fatty liver disease participants with lowâ decreasing homeostatic model assessmentâ β (referent: highâ decreasing) had the highest odds of prevalent (OR = 14.1, 3.9â 50.9) and incident (OR = 10.3, 2.7â 39.3) diabetes.ConclusionTrajectories of insulin resistance and βâ cell response during young and middle adulthood are robustly associated with diabetes risk in nonâ alcoholic fatty liver disease. Thus, how persons with nonâ alcoholic fatty liver disease develop resistance to insulin provides important information about risk of diabetes in midlife above and beyond degree of insulin resistance at the time of nonâ alcoholic fatty liver disease assessment.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146427/1/liv13747_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146427/2/liv13747.pd

Sex and race differences in the prevalence of fatty liver disease as measured by computed tomography liver attenuation in European American and African American participants of the NHLBI family heart study

Liver attenuation (LA) (Hounsfield Units, HU) by computed tomography (CT) is a validated quantitative measure inversely related to liver fat burden. We examined race-and sex- differences on the distribution of LA (one of the first stages of fatty liver disease) and the predictors of these mean differences in European American (EA) and African American (AA) participants of the Family Heart Study. A total of 1242 (1064 EA, 178 AA) and 1477 (1150 EA, 327 AA) men and women, respectively, underwent CT examination from which LA and abdominal adipose volume were measured. LA (adjusted for phantom and field center) was the dependent variable in linear mixed models (to control for family relatedness) that tested for mean differences by race and by sex. Independent explanatory variables included age, body mass index, visceral adipose tissue volume, subcutaneous adipose tissue volume, alcohol consumption, TG, HDL-C, and insulin resistance. Mean LA varied significantly by sex, [(men) 57.76 ±10.03 HU and (women) 60.03 ±10.91 HU, p=0.0002], but not by race. Higher LA was associated with older age, while higher values of VAT, triglycerides, and insulin resistance were associated with lower LA in men and women. In contrast, alcohol consumption and BMI were associated with lower LA only among men. In analyses stratified by race LA was associated with alcohol consumption, VAT, and insulin resistance in both EA and AA and with age, BMI, and HDL-C in EA participants only. Our study findings confirm that there are important sex differences and race by sex interaction effects on the distribution of liver attenuation, the prevalence of FLD, and on the influence of metabolic risk factors on LA and FLD

Consequence of the tumor-associated conversion to cyclin D1b.

Clinical evidence suggests that cyclin D1b, a variant of cyclin D1, is associated with tumor progression and poor outcome. However, the underlying molecular basis was unknown. Here, novel models were created to generate a genetic switch from cyclin D1 to cyclin D1b. Extensive analyses uncovered overlapping but non-redundant functions of cyclin D1b compared to cyclin D1 on developmental phenotypes, and illustrated the importance of the transcriptional regulatory functions of cyclin D1b in vivo. Data obtained identify cyclin D1b as an oncogene, wherein cyclin D1b expression under the endogenous promoter induced cellular transformation and further cooperated with known oncogenes to promote tumor growth in vivo. Further molecular interrogation uncovered unexpected links between cyclin D1b and the DNA damage/PARP1 regulatory networks, which could be exploited to suppress cyclin D1b-driven tumors. Collectively, these data are the first to define the consequence of cyclin D1b expression on normal cellular function, present evidence for cyclin D1b as an oncogene, and provide pre-clinical evidence of effective methods to thwart growth of cells dependent upon this oncogenic variant

Sloan Digital Sky Survey Imaging of Low Galactic Latitude Fields: Technical Summary and Data Release

The Sloan Digital Sky Survey (SDSS) mosaic camera and telescope have obtained five-band optical-wavelength imaging near the Galactic plane outside of the nominal survey boundaries. These additional data were obtained during commissioning and subsequent testing of the SDSS observing system, and they provide unique wide-area imaging data in regions of high obscuration and star formation, including numerous young stellar objects, Herbig-Haro objects and young star clusters. Because these data are outside the Survey regions in the Galactic caps, they are not part of the standard SDSS data releases. This paper presents imaging data for 832 square degrees of sky (including repeats), in the star-forming regions of Orion, Taurus, and Cygnus. About 470 square degrees are now released to the public, with the remainder to follow at the time of SDSS Data Release 4. The public data in Orion include the star-forming region NGC 2068/NGC 2071/HH24 and a large part of Barnard's loop.Comment: 31 pages, 9 figures (3 missing to save space), accepted by AJ, in press, see http://photo.astro.princeton.edu/oriondatarelease for data and paper with all figure