872 research outputs found
Composite Spectral Energy Distributions and Infrared-Optical Colors of Type 1 and Type 2 Quasars
We present observed mid-infrared and optical colors and composite spectral
energy distributions (SEDs) of type 1 (broad-line) and 2 (narrow-line) quasars
selected from Sloan Digital Sky Survey (SDSS) spectroscopy. A significant
fraction of powerful quasars are obscured by dust, and are difficult to detect
in optical photometric or spectroscopic surveys. However these may be more
easily identified on the basis of mid-infrared (MIR) colors and SEDs. Using
samples of SDSS type 1 type 2 matched in redshift and [OIII] luminosity, we
produce composite rest-frame 0.2-15 micron SEDs based on SDSS, UKIDSS, and
Wide-Field Infrared Survey Explorer (WISE) photometry and perform model fits
using simple galaxy and quasar SED templates. The SEDs of type 1 and 2 quasars
are remarkably similar, with the differences explained primarily by the
extinction of the quasar component in the type 2 systems. For both types of
quasar, the flux of the AGN relative to the host galaxy increases with AGN
luminosity (L_[OIII]) and redder observed MIR color, but we find only weak
dependencies of the composite SEDs on mechanical jet power as determined
through radio luminosity. We conclude that luminous quasars can be effectively
selected using simple MIR color criteria similar to those identified previously
(W1-W2 > 0.7 [Vega]), although these criteria miss many heavily obscured
objects. Obscured quasars can be further identified based on optical-IR colors
(for example, (u-W3 [AB]) > 1.4(W1-W2 [Vega])+3.2). These results illustrate
the power of large statistical studies of obscured quasars selected on the
basis of mid-IR and optical photometry.Comment: Accepted for publication in ApJ; 14 pages, 9 figures, 2 tables;
composite Type 1 and Type 2 quasar SEDs available at
http://www.dartmouth.edu/~hickox/Hickox2017_QSO_SED_Table1.tx
Histopathology of Explanted Lungs From Patients With a Diagnosis of Pulmonary Sarcoidosis
Background
Pathologic features of end-stage pulmonary sarcoidosis (ESPS) are not well defined; anecdotal reports have suggested that ESPS may mimic usual interstitial pneumonia (UIP). We hypothesized that ESPS has distinct histologic features.
Methods
Twelve patients who received a diagnosis of pulmonary sarcoidosis and underwent lung transplantation were included. Control subjects were 10 age- and sex-matched lung transplant patients with UIP. Hematoxylin and eosin-stained tissue sections were examined for the following features: extent/pattern of fibrosis; presence and quantity (per 10 high-power fields) of fibroblast foci and granulomas; distribution and morphology of granulomas; and presence and extent of honeycomb change. Extent of fibrosis and honeycomb change in lung parenchyma was scored as follows: 1 = 1% to 25%; 2 = 26% to 50%; 3 = 51% to 75%; 4 = 76% to 100% of lung parenchyma.
Results
Eight of 12 cases demonstrated histologic findings typical of ESPS. All showed well-formed granulomas with associated fibrosis distributed in a distinct lymphangitic fashion. Granulomas were present in hilar or mediastinal lymph nodes from six of six patients with ESPS and none of eight control subjects. The extent of fibrosis, honeycomb change, and fibroblast foci was significantly lower in ESPS cases compared with control cases. Two patients with remote histories of sarcoidosis showed histologic features of diseases other than ESPS (UIP and emphysema) without granulomas. Two patients with atypical clinical findings demonstrated nonnecrotizing granulomas combined with either severe chronic venous hypertension or UIP.
Conclusions
ESPS and UIP have distinct histopathologic features in the lungs. Patients with a pretransplant diagnosis of sarcoidosis may develop other lung diseases that account for their end-stage fibrosis
The Grizzly, November 2, 2017
Collegeville Election: Mayoral Candidate Targeted by Hate Flyer ā¢ Peace and Freedom Now! Ursinus Brings Hair to the Mainstage ā¢ AAAS Hosts Author and Journalist Lori Tharps ā¢ From Star Gazing to Volunteering, Watson Nominees Dream Big ā¢ Families Take Over Ursinus ā¢ Food Evolution Sparks Debate ā¢ Opinions: Weinstein Sexual Assault Scandal is a Call to Action; CSCG Speaker Series Response Reveals Gendered Assumptions ā¢ Palladino Accepted to 2018 Division III Immersion Program ā¢ Women\u27s Swimming Defeats Dickinsonhttps://digitalcommons.ursinus.edu/grizzlynews/1630/thumbnail.jp
The Grizzly, September 28, 2017
Constitution Day Sparks Student Discussions of Free Speech ā¢ Chin Brings Sexy Bad Girl Haikus, Asian American Blues Poems and Elegies to Ursinus Reading ā¢ Next Year\u27s Study Abroad Application Opens on October 3rd ā¢ Armstrong Lecture Brings Columbia University Historian Dr. Joshua Batts to Berman Museum ā¢ Home is Where the Bear is ā¢ New Species Comes to Ursinus ā¢ Opinions: Consciousness Raising Can Combat Rape Culture on Campus; Is This Sufjan Stevens Song Gay or Just About God? ā¢ Student Workers of the SMC ā¢ Pair of Wins Put Bears in Good Positionhttps://digitalcommons.ursinus.edu/grizzlynews/1626/thumbnail.jp
Podocytopenia and disease severity in IgA nephropathy
Podocytopenia and disease severity in IgA nephropathy.BackgroundIgA nephropathy is a common form of progressive glomerular disease, associated with proliferation of mesangial cells and mesangial deposition of IgA. The present study was designed to investigate functional and morphological covariates of disease severity in patients with IgA nephropathy.MethodsGlomerular hemodynamics, permselectivity and ultrastructure were studied in 17 adult patients with IgA nephropathy using inulin, para-aminohippuric acid (PAH) and 3H-Ficoll clearances and morphometric methods. A mathematical model of macromolecule permeation through a heteroporous membrane was used to characterize glomerular permselectivity. Controls consisted of 14 healthy living kidney donors and 12 healthy volunteers.ResultsThe patients were heterogeneous in their disease severity, but as a group had a decreased glomerular filtration rate (GFR) and increased urinary protein excretion compared to controls [63 Ā± 29 SD vs. 104 Ā± 23 mL/min/1.73 m2, P < 0.001, and (median) 1.34 vs. 0.11 g/day, P < 0.0001, respectively). A multivariate analysis of structural and functional relationships revealed GFR depression to be most strongly correlated with the prevalence of global glomerular sclerosis (t = -4.073, P = 0.002). Those patients with the most severe glomerular dysfunction had a reduced number of glomerular visceral epithelial cells (podocytes) per glomerulus. The degree of podocytopenia was related to the extent of glomerular sclerosis and of impairment of permselectivity and GFR, with worsening injury below an apparent threshold podocyte number of about 250 cells per glomerulus. There were no corresponding correlations between these indices of injury and the number of mesangial and endothelial cells.ConclusionsOur findings show that podocyte loss is a concomitant of increasing disease severity in IgA nephropathy. This suggests that podocyte loss may either cause or contribute to the progressive proteinuria, glomerular sclerosis and filtration failure seen in this disorder
A neuron-specific cytoplasmic dynein isoform preferentially transports TrkB signaling endosomes
Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)āIC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFPādynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes
Recent Space PV Concentrator Advances: More Robust, Lighter, and Easier to Track
Over the past three years, the authors have collaborated on several significant advances in space photovoltaic concentrator technology, including a far more robust Fresnel lens for sunlight concentration, improved color-mixing features for the lens to minimize chromatic aberration losses for next-generation 4-junction and 6-junction IMM cells, a new approach to suntracking requiring only one axis of rotation even in the presence of large beta angles (e.g., +/- 50 deg), a new waste heat radiator made of graphene, with 80-90% reduction in mass, and a new platform for deployment and support on orbit (SOLAROSA). These patent-pending advances are described in this paper
Learning to Obtain Reward, but Not Avoid Punishment, Is Affected by Presence of PTSD Symptoms in Male Veterans: Empirical Data and Computational Model
Post-traumatic stress disorder (PTSD) symptoms include behavioral avoidance which is acquired and tends to increase with time. This avoidance may represent a general learning bias; indeed, individuals with PTSD are often faster than controls on acquiring conditioned responses based on physiologically-aversive feedback. However, it is not clear whether this learning bias extends to cognitive feedback, or to learning from both reward and punishment. Here, male veterans with self-reported current, severe PTSD symptoms (PTSS group) or with few or no PTSD symptoms (control group) completed a probabilistic classification task that included both reward-based and punishment-based trials, where feedback could take the form of reward, punishment, or an ambiguous āno-feedbackā outcome that could signal either successful avoidance of punishment or failure to obtain reward. The PTSS group outperformed the control group in total points obtained; the PTSS group specifically performed better than the control group on reward-based trials, with no difference on punishment-based trials. To better understand possible mechanisms underlying observed performance, we used a reinforcement learning model of the task, and applied maximum likelihood estimation techniques to derive estimated parameters describing individual participantsā behavior. Estimations of the reinforcement value of the no-feedback outcome were significantly greater in the control group than the PTSS group, suggesting that the control group was more likely to value this outcome as positively reinforcing (i.e., signaling successful avoidance of punishment). This is consistent with the control groupās generally poorer performance on reward trials, where reward feedback was to be obtained in preference to the no-feedback outcome. Differences in the interpretation of ambiguous feedback may contribute to the facilitated reinforcement learning often observed in PTSD patients, and may in turn provide new insight into how pathological behaviors are acquired and maintained in PTSD
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