6,288 research outputs found
Against the Wind: Radio Light Curves of Type Ia Supernovae Interacting with Low-Density Circumstellar Shells
For decades, a wide variety of observations spanning the radio through
optical and on to the x-ray have attempted to uncover signs of type Ia
supernovae (SNe Ia) interacting with a circumstellar medium (CSM). The goal of
these studies is to constrain the nature of the hypothesized SN Ia mass-donor
companion. A continuous CSM is typically assumed when interpreting observations
of interaction. However, while such models have been successfully applied to
core-collapse SNe, the assumption of continuity may not be accurate for SNe Ia,
as shells of CSM could be formed by pre-supernova eruptions (novae). In this
work, we model the interaction of SNe with a spherical, low density,
finite-extent CSM and create a suite of synthetic radio synchrotron light
curves. We find that CSM shells produce sharply peaked light curves, and
identify a fiducial set of models that all obey a common evolution and can be
used to generate radio light curves for interaction with an arbitrary shell.
The relations obeyed by the fiducial models can be used to deduce CSM
properties from radio observations; we demonstrate this by applying them to the
non-detections of SN 2011fe and SN 2014J. Finally, we explore a multiple shell
CSM configuration and describe its more complicated dynamics and resultant
radio light curves.Comment: 15 pages, 11 figures, ApJ accepte
Newer treatments for fibromyalgia syndrome
Fibromyalgia syndrome is a common chronic pain disorder of unknown etiology. The lack of understanding of the pathophysiology of fibromyalgia has made this condition frustrating for patients and clinicians alike. The most common symptoms of this disorder are chronic widespread pain, fatigue, sleep disturbances, difficulty with memory, and morning stiffness. Emerging evidence points towards augmented pain processing within the central nervous system (CNS) as having a primary role in the pathophysiology of this disorder. Currently the two drugs that are approved by the United States Food and Drug Administration (FDA) for the management of fibromyalgia are pregabalin and duloxetine. Newer data suggests that milnacipran, a dual norepinephrine and serotonin reuptake inhibitor, may be promising for the treatment of fibromyalgia. A double-blind, placebo-controlled trial of milnacipran in 125 fibromyalgia patients showed significant improvements relative to placebo. Milnacipran given either once or twice daily at doses up to 200 mg/day was generally well tolerated and yielded significant improvements relative to placebo on measures of pain, patient’s global impression of change in their disease state, physical function, and fatigue. Future studies are needed to validate the efficacy of milnacipran in fibromyalgia
PTF11kx: A Type Ia Supernova with Hydrogen Emission Persisting After 3.5 Years
The optical transient PTF11kx exhibited both the characteristic spectral
features of Type Ia supernovae (SNe Ia) and the signature of ejecta interacting
with circumstellar material (CSM) containing hydrogen, indicating the presence
of a nondegenerate companion. We present an optical spectrum at days
after peak from Keck Observatory, in which the broad component of H
emission persists with a similar profile as in early-time observations. We also
present IRAC detections obtained and days after peak,
and an upper limit from ultraviolet imaging at days. We interpret
our late-time observations in context with published results - and reinterpret
the early-time observations - in order to constrain the CSM's physical
parameters and compare to theoretical predictions for recurrent nova systems.
We find that the CSM's radial extent may be several times the distance between
the star and the CSM's inner edge, and that the CSM column density may be two
orders of magnitude lower than previous estimates. We show that the H
luminosity decline is similar to other SNe with CSM interaction, and
demonstrate how our infrared photometry is evidence for newly formed,
collisionally heated dust. We create a model for PTF11kx's late-time CSM
interaction and find that X-ray reprocessing by photoionization and
recombination cannot reproduce the observed H luminosity, suggesting
that the X-rays are thermalized and that H radiates from collisional
excitation. Finally, we discuss the implications of our results regarding the
progenitor scenario and the geometric properties of the CSM for the PTF11kx
system.Comment: 15 pages, 8 figures, 3 tables; submitted to Ap
Facilitating moral maturity: integrating developmental and cultural approaches
This study integrates developmental and cultural approaches to student development and finds that millennial college students are responsive to moral formation. A particular challenge to prosociality among contemporary generations is growing up within a cultural context that aggrandizes a self-focus during emerging adulthood. Businesses are increasingly integrating spirituality at work, in part because of the benefits religiosity has in developing prosocial behaviors. However, businesses and universities can have concerns about explicitly engaging religiosity. We thus study a pedagogical approach that engages religiosity to investigate whether this promotes prosocial moral values. Employing a mixed-methods design, we analyze quantitative and qualitative changes in students completing a management education course with this pedagogical approach and compare their changes over time to a control group completing conventional ethics courses during the same time period. Findings indicate that prosocial development is possible during college and that explicit attention to diverse religious views aids moral development
Recommended from our members
Effect of a Fruit and Vegetable Prescription Program on Children's Fruit and Vegetable Consumption.
IntroductionMost children in families with low income do not meet dietary guidance on fruit and vegetable consumption. Fruit and vegetable prescription programs improve access to and affordability of health-supporting foods for adults, but their effect on dietary behavior among children is not known. The objective of this study was to describe the extent to which exposure to a fruit and vegetable prescription program was associated with changes in consumption among participants aged 2 to 18.MethodsWe used data from a modified National Cancer Institute screener to calculate fruit and vegetable intake among 883 children who were overweight or had obesity and participated in a 4- to 6-month fruit and vegetable prescription program at federally qualified health centers during 4 years (2012-2015). Secondary analyses in 2017 included paired t tests to compare change in fruit and vegetable consumption (cups/day) between first and last visits and multivariable linear regressions, including propensity dose-adjusted models, to model this change as a function of sociodemographic and program-specific covariates, such as number of clinical visits and value of prescription redemption.ResultsWe found a dose propensity-adjusted increase of 0.32 cups (95% confidence interval, 0.19-0.45 cups) for each additional visit while holding constant the predicted number of visits and site. An equal portion of the change-score increase was attributed to vegetable consumption and fruit consumption (β = 0.16 for each).ConclusionFruit and vegetable prescription programs in clinical settings may increase fruit and vegetable consumption among children in low-income households. Future research should use a comparison group and consider including qualitative analysis of site-specific barriers and facilitators to success
Blue Swimmer Crab ( Portunus armatus ) and Mud Crab Scylla serrata and Scylla olivacea ) Resources in the North Coast and Gascoyne Coast Bioregions, Western Australia
Blue swimmer crab (Portunus armatus) are found along the entire Western Australia (WA) coast, in a range of estuarine, inshore and continental shelf areas (\u3c50 m). In the North Coast Bioregion (NCB), commercial fishing primarily occurs as part of the Pilbara Crab Managed Fishery (PCMF) which spans the inshore waters from Onslow through to Port Hedland, with most fishing activity taking place around Nickol Bay
Blue Swimmer Crab ( Portunus armatus ) Resource in the West Coast Bioregion, Western Australia Part 1: Peel Harvey Estuary, Cockburn Sound and Swan Canning Estuary
Blue swimmer crabs (Portunus armatus) are found along the entire coastline of Western Australia in a range of estuarine, inshore and continental shelf areas (\u3c50 m). In the West Coast Bioregion (WCB), crab fisheries are centred in estuaries and coastal embayments from Geographe Bay to the Swan River. Commercial fisheries include the Cockburn Sound Crab Managed Fishery (CSCMF), the Warnbro Sound Crab Managed Fishery, the Swan-Canning Estuary (SCE) Crab Fishery (Area 1 of the West Coast Estuarine Managed Fishery (WCEMF)), Peel-Harvey Crab Fishery (Area 2 of the WCEMF), Hardy Inlet (Area 3 of the WCEMF) and the Mandurah to Bunbury Developing Crab Fishery (Area 1, Comet Bay and Area 2, Mandurah-Bunbury)
Statistical Properties of Avalanches in Networks
We characterize the distributions of size and duration of avalanches
propagating in complex networks. By an avalanche we mean the sequence of events
initiated by the externally stimulated `excitation' of a network node, which
may, with some probability, then stimulate subsequent firings of the nodes to
which it is connected, resulting in a cascade of firings. This type of process
is relevant to a wide variety of situations, including neuroscience, cascading
failures on electrical power grids, and epidemology. We find that the
statistics of avalanches can be characterized in terms of the largest
eigenvalue and corresponding eigenvector of an appropriate adjacency matrix
which encodes the structure of the network. By using mean-field analyses,
previous studies of avalanches in networks have not considered the effect of
network structure on the distribution of size and duration of avalanches. Our
results apply to individual networks (rather than network ensembles) and
provide expressions for the distributions of size and duration of avalanches
starting at particular nodes in the network. These findings might find
application in the analysis of branching processes in networks, such as
cascading power grid failures and critical brain dynamics. In particular, our
results show that some experimental signatures of critical brain dynamics
(i.e., power-law distributions of size and duration of neuronal avalanches),
are robust to complex underlying network topologies.Comment: 11 pages, 7 figure
Real Voices, Real Questions, Real Engagement: VCU Speaker Series
You come here for something more than schooling. You come here for deep education and deep education is about learning how to die so that you learn how to live because when you examine certain assumptions that you have, certain presuppositions that you’re holding on to, when you let them go, that’s a form of death. And there’s no growth, there’s no development, there’s no maturation without learning how to die and giving up certain dogma, giving up certain doctrine. - Cornel West, Ph.D., VCU Siegel Center, Fall 2015
VCU is a large, public, urban research university situated in the middle of a capital city. Its faculty, staff, student body, alumni, and the surrounding community are remarkably diverse as are the academic offerings. It is, and should be viewed as, the intellectual and cultural engine of the region. Our project proposes the creation of a large-scale, high-profile speaker series designed to highlight emerging trends and provide students, faculty, staff, alumni and the Richmond community with a forum for conversation. The speaker series will cover topics that are critically engaging, have national relevance, and introduce ideas that propel the next generation of leaders. In addition to a large speaking engagement, the speaker series will also incorporate other activities to cultivate interactions and build relationships such as classroom lectures, book signings, and a dinner through the development office. The speaker series will host at least one speaker annually, with the addition of a second speaker as the event builds momentum. At least one of the lectures will occur at the beginning of the traditional academic semester, allowing for the greatest opportunity for participation across VCU and Richmond. Internal support from VCU students, faculty, staff, and colleges will ensure that the project is connected to the mission, vision, goals, and pursuits of VCU. A speaker series committee will help sustain and coordinate efforts across the university and community. Committee members will include stakeholders that require buy-in and cooperation for activities that complement the speaker series (e.g., other lectures, panel discussions, classroom activities). A survey will be used to gain insights into topics and speakers of interest. The committee will review the survey responses in order to make informed decisions during the planning process. The ongoing presence of hosting influential speakers will allow VCU to emerge into the national spotlight as thought-leaders. This speaker series will serve many purposes. First, the series will serve to inspire VCU students, faculty, staff, and the Richmond. Through frank and open conversations attendees will be exposed to new concepts and ideas. Second, the series will unite the diverse groups that make up VCU and the Richmond community. The lecture series will expose attendees to new ideas and open doors for possible opportunities for collaboration through classroom and community engagement activities related to the topics discussed. Third, the series will serve as a cultural conduit, solidly connecting the VCU and Richmond communities around engaging ideas of importance. Opening a new market-place of ideas will ensure that the students of VCU interact with new information in exciting and transformative ways
- …