604 research outputs found
Constraints on the Progenitor System of the Type Ia Supernova 2014J from Pre-Explosion Hubble Space Telescope Imaging
We constrain the properties of the progenitor system of the highly reddened
Type Ia supernova (SN) 2014J in Messier 82 (M82; d ~ 3.5 Mpc). We determine the
SN location using Keck-II K-band adaptive optics images, and we find no
evidence for flux from a progenitor system in pre-explosion near-ultraviolet
through near-infrared Hubble Space Telescope (HST) images. Our upper limits
exclude systems having a bright red giant companion, including symbiotic novae
with luminosities comparable to that of RS Ophiuchi. While the flux constraints
are also inconsistent with predictions for comparatively cool He-donor systems
(T < ~35,000 K), we cannot preclude a system similar to V445 Puppis. The
progenitor constraints are robust across a wide range of R_V and A_V values,
but significantly greater values than those inferred from the SN light curve
and spectrum would yield proportionally brighter luminosity limits. The
comparatively faint flux expected from a binary progenitor system consisting of
white dwarf stars would not have been detected in the pre-explosion HST
imaging. Infrared HST exposures yield more stringent constraints on the
luminosities of very cool (T < 3000 K) companion stars than was possible in the
case of SN Ia 2011fe.Comment: Accepted by ApJ 14 May 2014 with only minor revision
Many Democrats think that the 2016 election result was rigged
Previous studies have found that after an election, supporters of the losing candidate tend to be more likely to believe that votes were counted improperly. So how did Donald Trump's claims that the 2016 election was 'rigged' ahead of his own victory influence voters' perception of the election's integrity? Using national survey data, Betsy Sinclair, Steven S. Smith and Patrick Tucker find that Republicans gained confidence in the vote after Trump’s election win, while Democrats’ confidence fell. This effect was even more pronounced among bettereducated Republicans and Democrats who identified most strongly with their party
The Increasing Financial Impact of Chronic Kidney Disease in Australia
The aim of this investigation was to determine and compare current and projected expenditure associated with chronic kidney disease (CKD), renal replacement therapy (RRT), and cardiovascular disease (CVD) in Australia. Data published by Australia and New Zealand Dialysis and Transplant Registry, Australian Institute of Health and Welfare, and World Bank were used to compare CKD-, RRT-, and CVD-related expenditure and prevalence rates. Prevalence and expenditure predictions were made using a linear regression model. Direct statistical comparisons of rates of annual increase utilised indicator variables in combined regressions. Statistical significance was set at P<0.05. Dollar amounts were adjusted for inflation prior to analysis. Between 2012 and 2020, prevalence, per-patient expenditure, and total disease expenditure associated with CKD and RRT are estimated to increase significantly more rapidly than CVD. RRT prevalence is estimated to increase by 29%, compared to 7% in CVD. Average annual RRT per-patient expenditure is estimated to increase by 16%, compared to 8% in CVD. Total CKD- and RRT-related expenditure had been estimated to increase by 37%, compared to 14% in CVD. Per-patient, CKD produces a considerably greater financial impact on Australia’s healthcare system, compared to CVD. Research focusing on novel preventative/therapeutic interventions is warranted
Chronic Kidney Disease Influences Multiple Systems: Describing the Relationship between Oxidative Stress, Inflammation, Kidney Damage, and Concomitant Disease
Chronic kidney disease (CKD) is characterized by increased levels of oxidative stress and inflammation. Oxidative stress and inflammation promote renal injury via damage to molecular components of the kidney. Unfortunately, relationships between inflammation and oxidative stress are cyclical in that the inflammatory processes that exist to repair radical-mediated damage may be a source of additional free radicals, resulting in further damage to renal tissue. Oxidative stress and inflammation also have the ability to become systemic, serving to injure tissues distal to the site of original insult. This review describes select mediators in the exacerbatory relationship between oxidative stress, inflammation, and CKD. This review also discusses oxidative stress, inflammation, and CKD as they pertain to the development and progression of common CKD-associated comorbidities. Lastly, the utility of several widely accessible and cost-effective lifestyle interventions and their ability to reduce oxidative stress and inflammation are discussed and recommendations for future research are provided
The effects of age on skeletal muscle and the phosphocreatine energy system: can creatine supplementation help older adults
Creatine supplementation has been found to significantly increase muscle strength and hypertrophy in young adults (≤ 35 yr) particularly when consumed in conjunction with a resistance training regime. Literature examining the efficacy of creatine supplementation in older adults (55-82 yr) suggests creatine to promote muscle strength and hypertrophy to a greater extent than resistance training alone. The following is a review of literature reporting on the effects of creatine supplementation on intramuscular high energy phosphates, skeletal muscle morphology and quality of life in older adults. Results suggest creatine supplementation to be a safe, inexpensive and effective nutritional intervention, particularly when consumed in conjunction with a resistance training regime, for slowing the rate of muscle wasting that is associated with aging. Physicians should strongly consider advising older adults to supplement with creatine and to begin a resistance training regime in an effort to enhance skeletal muscle strength and hypertrophy, resulting in enhanced quality of life
Automated Low-Gravitation Facility Would Make Optical Fibers
A report describes a proposed automated facility that would be operated in outer space to produce high-quality optical fibers from fluoride-based glasses, free of light-scattering crystallites that form during production in normal Earth gravitation. Before launch, glass preforms would be loaded into a mechanism that would later dispense them. A dispensed preform would be melted, cooled to its glass-transition temperature rapidly enough to prevent crystallization, cooled to ambient temperature, then pushed into a preform tip heater, wherein it would be reheated to the softening temperature. A robotic manipulator would touch a fused silica rod to the softened glass to initiate pulling of a fiber. The robot would pull the fiber to an attachment on a take-up spool, which would thereafter be turned to pull the fiber. The diameter of the fiber would depend on the pulling speed and the viscosity of the glass at the preform tip. Upon depletion of a preform, the robot would place the filled spool in storage and position an empty spool to pull a fiber from a new preform. Pulling would be remotely monitored by a video camera and restarted by remote command if a break in the fiber were observed
The Tevatron at the Frontier of Dark Matter Direct Detection
Direct detection of dark matter (DM) requires an interaction of dark matter
particles with nucleons. The same interaction can lead to dark matter pair
production at a hadron collider, and with the addition of initial state
radiation this may lead to mono-jet signals. Mono-jet searches at the Tevatron
can thus place limits on DM direct detection rates. We study these bounds both
in the case where there is a contact interaction between DM and the standard
model and where there is a mediator kinematically accessible at the Tevatron.
We find that in many cases the Tevatron provides the current best limit,
particularly for light dark matter, below 5 GeV, and for spin dependent
interactions. Non-standard dark matter candidates are also constrained. The
introduction of a light mediator significantly weakens the collider bound. A
direct detection discovery that is in apparent conflict with mono-jet limits
will thus point to a new light state coupling the standard model to the dark
sector. Mono-jet searches with more luminosity and including the spectrum shape
in the analysis can improve the constraints on DM-nucleon scattering cross
section.Comment: 20 pages, 8 figures, final version in JHE
Searches for Long Lived Neutral Particles
An intriguing possibility for TeV scale physics is the existence of neutral
long lived particles (LOLIPs) that subsequently decay into SM states. Such
particles are many cases indistinguishable from missing transverse energy (MET)
at colliders. We propose new methods to search for these particles using
neutrino telescopes. We study their detection prospects, assuming production
either at the LHC or through dark matter (DM) annihilations in the Sun and the
Earth. We find that the sensitivity for LOLIPs produced at the LHC is limited
by luminosity and detection energy thresholds. On the other hand, in the case
of DM annihilation into LOLIPs, the sensitivity of neutrino telescopes is
promising and may extend beyond the reach of upcoming direct detection
experiments. In the context of low scale hidden sectors weakly coupled to the
SM, such indirect searches allow to probe couplings as small as 10^-15.Comment: 22 pages, 6 figure
Impact of Virtual Simulation and Coaching on the Interpersonal Collaborative Communication Skills of Speech-Language Pathology Students: A Pilot Study
Communication between clinicians, teachers, and family members is a critical skill when addressing and providing for the individual needs of patients. However, graduate students in speech-language pathology (SLP) programs often have limited opportunities to practice these skills prior to or during externship placements. The purpose of this study was to explore the use of virtual-reality based rehearsal with coaching on the interpersonal collaborative communication skills of SLP graduate students when delivering information regarding a singular patient to different stakeholders. Three graduate students completing their third semester in a SLP program participated in the study. Each participant was provided a clinical case scenario and asked to deliver recommendations related to the client’s communication abilities to a single adult avatar portraying either a parent, teacher, or pediatrician. This task was repeated twice to allow assessment of performance across multiple trials. A brief reflection and coaching period was provided between trials with the same avatar. All interactions were scored using the Situation, Background, Assessment, Recommendation, and Communication (SBAR-C) tool. All participants demonstrated improved communication skills between their first and second trial with each avatar as measured by the SBAR-C. Social validity surveys with participants revealed that they found the intervention to be valid and acceptable
Tertiary-Treated Municipal Wastewater is a Significant Point Source of Antibiotic Resistance Genes Into Duluth-Superior Harbor
In this study, the impact of tertiary-treated municipal wastewater on the quantity of several antibiotic resistance determinants in Duluth-Superior Harbor was investigated by collecting surface water and sediment samples from 13 locations in Duluth-Superior Harbor, the St. Louis River, and Lake Superior. Quantitative PCR (qPCR) was used to target three different genes encoding resistance to tetracycline (tet(A), tet(X), and tet(W)), the gene encoding the integrase of class 1 integrons (intI1), and total bacterial abundance (16S rRNA genes) as well as total and human fecal contamination levels (16S rRNA genes specific to the genus Bacteroides). The quantities of tet(A), tet(X), tet(W), intI1, total Bacteroides, and human-specific Bacteroides were typically 20-fold higher in the tertiary-treated wastewater than in nearby surface water samples. In contrast, the quantities of these genes in the St. Louis River and Lake Superior were typically below detection. Analysis of sequences of tet(W) gene fragments from four different samples collected throughout the study site supported the conclusion that tertiary-treated municipal wastewater is a point source of resistance genes into Duluth-Superior Harbor. This study demonstrates that the discharge of exceptionally treated municipal wastewater can have a statistically significant effect on the quantities of antibiotic resistance genes in otherwise pristine surface waters
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