Quasar Black Hole Mass Estimates in the Era of Time Domain Astronomy

We investigate the dependence of the normalization of the high-frequency part of the X-ray and optical power spectral densities (PSD) on black hole mass for a sample of 39 active galactic nuclei (AGN) with black hole masses estimated from reverberation mapping or dynamical modeling. We obtained new Swift observations of PG 1426+015, which has the largest estimated black hole mass of the AGN in our sample. We develop a novel statistical method to estimate the PSD from a lightcurve of photon counts with arbitrary sampling, eliminating the need to bin a lightcurve to achieve Gaussian statistics, and we use this technique to estimate the X-ray variability parameters for the faint AGN in our sample. We find that the normalization of the high-frequency X-ray PSD is inversely proportional to black hole mass. We discuss how to use this scaling relationship to obtain black hole mass estimates from the short time-scale X-ray variability amplitude with precision ~ 0.38 dex. The amplitude of optical variability on time scales of days is also anti-correlated with black hole mass, but with larger scatter. Instead, the optical variability amplitude exhibits the strongest anti-correlation with luminosity. We conclude with a discussion of the implications of our results for estimating black hole mass from the amplitude of AGN variability.Comment: 19 pages, 10 figures, emulateapj format, submitted to Ap

Applying Theory of Constraints to Timber Harvesting: A Case Study from the Northeast USA

Logging firms are a critical link in wood supply chains, connecting forest landowners with markets for wood products. Improving operational planning can benefit individual logging firms as well as the larger wood supply chain in which they operate. Applying concepts from Theory of Constraints (TOC) to timber harvesting may help achieve greater predictability and efficiency when planning harvest operations. However, examples that demonstrate how TOC can improve logging operations are lacking. This study focuses on the analysis of production and activity data collected during the harvest of a temperate mixed hardwood forest in the Northeast United States using a chainsaw-forwarder system through a TOC lens. Specifically, the drum-buffer-rope (DBR) method was used to reschedule operator and machine activities such that a consistent flow of wood from stump to landing was maintained despite anticipated production setbacks. The results of this case study provide insights into the usefulness of applying TOC to logging operations. In particular, logging businesses must be able to estimate machine and operator productivity within a given harvest context to identify and exploit system constraints, while taking full advantage of unused capacity of any non-constraint functions

False discovery rate regression: an application to neural synchrony detection in primary visual cortex

Many approaches for multiple testing begin with the assumption that all tests in a given study should be combined into a global false-discovery-rate analysis. But this may be inappropriate for many of today's large-scale screening problems, where auxiliary information about each test is often available, and where a combined analysis can lead to poorly calibrated error rates within different subsets of the experiment. To address this issue, we introduce an approach called false-discovery-rate regression that directly uses this auxiliary information to inform the outcome of each test. The method can be motivated by a two-groups model in which covariates are allowed to influence the local false discovery rate, or equivalently, the posterior probability that a given observation is a signal. This poses many subtle issues at the interface between inference and computation, and we investigate several variations of the overall approach. Simulation evidence suggests that: (1) when covariate effects are present, FDR regression improves power for a fixed false-discovery rate; and (2) when covariate effects are absent, the method is robust, in the sense that it does not lead to inflated error rates. We apply the method to neural recordings from primary visual cortex. The goal is to detect pairs of neurons that exhibit fine-time-scale interactions, in the sense that they fire together more often than expected due to chance. Our method detects roughly 50% more synchronous pairs versus a standard FDR-controlling analysis. The companion R package FDRreg implements all methods described in the paper

Assessment of benefit of advanced inflammatory bowel disease training: Challenges and solutions

BACKGROUND: Advanced inflammatory bowel disease (IBD) fellowships are available for gastroenterologists who wish to increase their expertise in complex IBD. However, little is known about the outcomes of such training. The aims of this study were to assess clinical and academic outcomes following advanced training in IBD. METHODS: We surveyed gastroenterologists who completed advanced IBD fellowships and compared competency and outcomes to gastroenterologists focusing in IBD who completed gastroenterology training alone. Participants completed a survey via REDCap. Continuous variables were compared using the Wilcoxon rank-sum test. Categorical variables were compared using chi-square or Fisher\u27s exact tests. RESULTS: A total of 104 physicians participated in the study. IBD fellowships were completed by 31 physicians (30%), of whom 29 (94%) felt their training was excellent. Management of complicated IBD (84%), research mentoring (74%), and career mentoring (71%) were felt to contribute most highly to professional development. Compared to non-advanced trained physicians, advanced trained physicians expressed higher levels of comfort with management of IBD during pregnancy ( CONCLUSIONS: This study suggests there may be clinical benefit to advanced IBD training. Importantly, this study identified that there are also unique challenges to the assessment of clinical competency in IBD training. Efforts by the IBD community to establish a registry of advanced trainees and improve competency assessments are needed

A Novel Concept for a Positron Emission Tomography Scanner

Positron Emission Tomography (PET) allows physicians and researchers to visualize metabolic data in the human body and is widely used in cancer and neurological imaging. Traditional PET scanners consist of a thin ring of scintillators coupled to photo detectors but these scanners often take long periods of time to acquire an image, are very costly, and are too complex to fit inside other machinery such as MRI. In response to this, we are building a novel PET detector that utilizes non-traditional scintillators and photo detectors in an attempt to significantly decrease cost, allow combined PET/MRI modalities and reduce scan time

Montane meadow change during drought varies with background hydrologic regime and plant functional group

Climate change models for many ecosystems predict more extreme climatic events in the future, including exacerbated drought conditions. Here we assess the effects of drought by quantifying temporal variation in community composition of a complex montane meadow landscape characterized by a hydrological gradient. The meadows occur in two regions of the Greater Yellowstone Ecosystem (Gallatin and Teton) and were classified into six categories (M1–M6, designating hydric to xeric) based upon Satellite pour l’Observation de la Terre (SPOT) satellite imagery. Both regions have similar plant communities, but patch sizes of meadows are much smaller in the Gallatin region. We measured changes in the percent cover of bare ground and plants by species and functional groups during five years between 1997 and 2007. We hypothesized that drought effects would not be manifested evenly across the hydrological gradient, but rather would be observed as hotspots of change in some areas and minimally evident in others. We also expected varying responses by plant functional groups (forbs vs. woody plants). Forbs, which typically use water from relatively shallow soils compared to woody plants, were expected to decrease in cover in mesic meadows, but increase in hydric meadows. Woody plants, such as Artemisia, were expected to increase, especially in mesic meadows. We identified several important trends in our meadow plant communities during this period of drought: (1) bare ground increased significantly in xeric meadows of both regions (Gallatin M6 and Teton M5) and in mesic (M3) meadows of the Teton, (2) forbs decreased significantly in the mesic and xeric meadows in both regions, (3) forbs increased in hydric (M1) meadows of the Gallatin region, and (4) woody species showed increases in M2 and M5 meadows of the Teton region and in M3 meadows of the Gallatin region. The woody response was dominated by changes in Artemisia spp. and Chrysothamnus viscidiflorus. Thus, our results supported our expectations that community change was not uniform across the landscape, but instead could be predicted based upon functional group responses to the spatial and temporal patterns of water availability, which are largely a function of plant water use and the hydrological gradient.This material is based upon research supported by the National Science Foundation under Grants 0518150 and EPS0814387, the Environmental Protection Agency under STAR Grant R825155, the University of Wyoming National Park Service Research Station, and the Grand Teton Natural History Association. We thank the University of Wyoming National Park Service Research Station (particularly Henry Harlow and Sue Consolo-Murphy) and the U.S. Forest Service for providing support and housing. Philip Dixon provided statistical consulting, and Mark Jakubauskas collaborated in setting up our initial field campaigns. Edward Cook assisted in selection and assessment of PDSI data; and Lisa Graumlich, Andy Bunn, Steve Gray, and Jeremy Littel advised us on climate reconstruction options for the GYE. Scott Creel, Sue Fairbanks, and Matt Kaufmann provided information on elk population trends in the region. Jill Sherwood designed the map. William Clark and two anonomous reviewers provided important suggestions that helped improve the manuscript. Finally, we thank the many research technicians and field assistants who helped in the fieldwork

Weather Design Considerations for the TASAR Traffic Aware Planner

The Traffic Aware Planner (TAP) is a decision support automation tool for trajectory planning and optimization intended for use on todays flight deck. Drawing from a variety of on- and off-board data sources, TAP employs a sophisticated trajectory optimization algorithm that provides the aircrew with fuel- and time-saving reroute recommendations that are free of known conflicts with traffic, special use airspace, and severe convective weather. As this kind of weather is a significant part of the pilots decision-making process while planning trajectory changes en route, a series of investigations has been conducted into the integration of weather data and associated functionality into the TAP software. This paper reviews the weather data sources and functionality that have been incorporated into TAP to date, along with experience gathered in the course of the design process

Anxious/depressed symptoms are related to microstructural maturation of white matter in typically developing youths

AbstractThere are multiple recent reports of an association between anxious/depressed (A/D) symptomatology and the rate of cerebral cortical thickness maturation in typically developing youths. We investigated the degree to which anxious/depressed symptoms are tied to age-related microstructural changes in cerebral fiber pathways. The participants were part of the NIH MRI Study of Normal Brain Development. Child Behavior Checklist A/D scores and diffusion imaging were available for 175 youths (84 males, 91 females; 241 magnetic resonance imagings) at up to three visits. The participants ranged from 5.7 to 18.4 years of age at the time of the scan. Alignment of fractional anisotropy data was implemented using FSL/Tract-Based Spatial Statistics, and linear mixed model regression was carried out using SPSS. Child Behavior Checklist A/D was associated with the rate of microstructural development in several white matter pathways, including the bilateral anterior thalamic radiation, bilateral inferior longitudinal fasciculus, left superior longitudinal fasciculus, and right cingulum. Across these pathways, greater age-related fractional anisotropy increases were observed at lower levels of A/D. The results suggest that subclinical A/D symptoms are associated with the rate of microstructural development within several white matter pathways that have been implicated in affect regulation, as well as mood and anxiety psychopathology.</jats:p

Survivorship support in head and neck cancer: American Head and Neck Society survey

BackgroundThe value of supporting cancer survivors beyond formal treatment has become increasingly recognized among clinicians who care for patients with head and neck cancer.MethodsA survey was developed by the American Head and Neck Society (AHNS) Survivorship Committee and distributed to members of the AHNS electronically.ResultsThe survey was distributed to 1403 AHNS members, with 202 responses (14.4%). Among survivorship topics, respondents were most likely to address detection of recurrence/second primary malignancies (97.5%), dysphagia (93.1%), and thyroid function (90.1%) with their patients; they were least likely to address sleep disturbance/apnea (27.7%) and body and self‐image issues (29.7%.) Less than half provide patients with a written treatment summary (43.1%) or follow‐up care plan (36.9%).ConclusionsThese results highlight the need for improved survivorship care planning and offer an opportunity for the development of educational and survivorship research in head and neck cancer care.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154907/1/hed26066_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154907/2/hed26066.pd