1,912 research outputs found
Comparability of Functional MRI Response in Young and Old During Inhibition
When using fMRI to study age-related cognitive changes, it is important to establish the integrity of the hemodynamic response because, potentially, it can be affected by age and disease. However, there have been few attempts to document such integrity and no attempts using higher cognitive rather than perceptual or motor tasks. We used fMRI with 28 healthy young and older adults on an inhibitory control task. Although older and young adults differed in task performance and activation patterns, they had comparable hemodynamic responses. We conclude that activation during cognitive inhibition, which was predominantly increased in elders, was not due to vascular confounds or specific changes in hemodynamic coupling
Fuel-Supply-Limited Stellar Relaxation Oscillations: Application to Multiple Rings around AGB Stars and Planetary Nebulae
We describe a new mechanism for pulsations in evolved stars: relaxation
oscillations driven by a coupling between the luminosity-dependent mass-loss
rate and the H fuel abundance in a nuclear-burning shell. When mass loss is
included, the outward flow of matter can modulate the flow of fuel into the
shell when the stellar luminosity is close to the Eddington luminosity . When the luminosity drops below , the mass outflow declines
and the shell is re-supplied with fuel. This process can be repetitive. We
demonstrate the existence of such oscillations and discuss the dependence of
the results on the stellar parameters. In particular, we show that the
oscillation period scales specifically with the mass of the H-burning
relaxation shell (HBRS), defined as the part of the H-burning shell above the
minimum radius at which the luminosity from below first exceeds the Eddington
threshold at the onset of the mass loss phase. For a stellar mass M_*\sim
0.7\Msun, luminosity L_*\sim 10^4\Lsun, and mass loss rate |\dot M|\sim
10^{-5}\Msun yr, the oscillations have a recurrence time
years , where is the timescale for
modulation of the fuel supply in the HBRS by the varying mass-loss rate. This
period agrees with the 1400-year period inferred for the spacings
between the shells surrounding some planetary nebulae, and the the predictied
shell thickness, of order 0.4 times the spacing, also agrees reasonably well.Comment: 15 pages TeX, 1 ps figure submitted to Ap
GP Participation and Recruitment of Patients to RCTs: Lessons from Trials of Acupuncture and Exercise for Low Back Pain in Primary Care
The objective of this study was to identify factors associated with general practitioner (GP) participation and the recruitment of people to trials in primary care, based on data from two trials of interventions for treating chronic low back pain. The study was based on data from two randomized controlled trials (RCTs), one involving exercise, the other acupuncture, and subsequent reporting by GPs in a postal questionnaire. The exercise trial achieved 62% recruitment whereas the acupuncture trial achieved 100% recruitment. In both trials GPs most efficient at referring patients were those with a special interest in the subject area, and those known personally to the research team. A follow-up GP questionnaire found that both trials had maintained a high profile with over 80% of GPs, and successful recruitment strategies included project reminder letters, updates and personal contacts. Achieving target recruitment of patients in the acupuncture trial was aided by the deliberate application of lessons learned in the exercise trial, in particular the need to keep initial study entry criteria broad, with subsequent filtering undertaken by the study researcher. In addition the use of effective methods of maintaining the trial profile, the involvement of a GP advisor, the decision to maximize the recruitment of GPs early in the trial and the direct recruitment of interested individual GPs. The successful recruitment of patients to trials in primary care requires careful planning and continuous monitoring from the outset. Prior to starting recruitment, it is useful to identify previous trials in a similar environment in order to learn from their experience and optimize patient recruitment
The Southern Flying Squirrel (\u3ci\u3eGlaucomys volans\u3c/i\u3e) in Lincoln, Nebraska
The southern flying squirrel (Glaucomys volans) is considered a species of greatest conservation need in Nebraska and listed as threatened in the state. Historically, the geographic range of the southern flying squirrel in Nebraska has been restricted to five eastern counties from a northern suburb of Omaha, Douglas Co., southward in the four counties of Sarpy, Otoe, Nemaha, and Richardson, all bordering the Missouri River on the east. In late November of 2018, a resident of Lincoln, Lancaster Co., Nebraska, contacted the Nebraska Game and Parks Commission about an animal found dead in his yard. This animal proved to be a southern flying squirrel, which was 50 [80 km] to 70 [112 km] miles west of the known geographic range of the species. Two additional individuals were subsequently observed at the original residence as were individuals in at least eight separate neighborhoods throughout the city of Lincoln. Clearly, a population of the southern flying squirrels is established and reproducing in Lincoln, but their origin is unknown. The source of this city-dwelling population may be from released/escaped pets, a natural dispersal from the Missouri River via the Platte River and Salt Creek, or inadvertent translocation when moving timber or fire wood
Evaluation of pregnancy outcomes in patients with multiple sclerosis after fingolimod exposure
Background and Methods: Limited data are available on the safety of fingolimod in pregnant women. We estimated the risk of adverse pregnancy outcomes in women with multiple sclerosis (MS) exposed to fingolimod either shortly before or during pregnancy in prospectively collected cases from clinical trials, observational studies, surveillance programs, and spontaneous reports.Results: The prevalence of major malformations among live births does not appear to be significantly higher than those in the general population and the unexposed MS population. Similarly, the prevalence of cardiac malformations observed in this analysis was not significantly different from that of the general population. Proportions of miscarriage were in line with those of the general and unexposed MS population and no specific pattern of birth defects was identified.Conclusions: These data can help inform healthcare professionals and women with MS exposed to fingolimod during conception.</p
The Application and Performance of Single Nucleotide Polymorphism Markers for Population Genetic Analyses of Lepidoptera
Microsatellite markers are difficult to apply within lepidopteran studies due to the lack of locus-specific PCR amplification and the high proportion of “null” alleles, such that erroneous estimations of population genetic parameters often result. Herein single nucleotide polymorphism (SNP) markers are developed from Ostrinia nubilalis (Lepidoptera: Crambidae) using next generation expressed sequence tag (EST) data. A total of 2742 SNPs were predicted within a reference assembly of 7414 EST contigs, and a subset of 763 were incorporated into 24 multiplex PCR reactions. To validate this pipeline, 5 European and North American sample sites were genotyped at 178 SNP loci, which indicated 84 (47.2%) were in Hardy–Weinberg equilibrium. Locus-by-locus FST, analysis of molecular variance, and STRUCTURE analyses indicate significant genetic differentiation may exist between European and North American O. nubilalis. The observed genetic diversity was significantly lower among European sites, which may result from genetic drift, natural selection, a genetic bottleneck, or ascertainment bias due to North American origin of EST sequence data. SNPs are an abundant source of mutation data for molecular genetic marker development in non-model species, with shared ancestral SNPs showing application within closely related species. These markers offer advantages over microsatellite markers for genetic and genomic analyses of Lepidoptera, but the source of mutation data may affect the estimation of population parameters and likely need to be considered in the interpretation of empirical data
A major radio outburst in III Zw 2 with an extremely inverted, millimeter-peaked spectrum
III Zw 2 is a spiral galaxy with an optical spectrum and faint extended radio
structure typical of a Seyfert galaxy, but also with an extremely variable,
blazar-like radio core. We have now discovered a new radio flare where the
source has brightened more than twenty-fold within less than two years. A
broad-band radio spectrum between 1.4 and 666 GHz shows a textbook-like
synchrotron spectrum peaking at 43 GHz, with a self-absorbed synchrotron
spectral index +2.5 at frequencies below 43 GHz and an optically thin spectral
index -0.75 at frequencies above 43 GHz. The outburst spectrum can be well
fitted by two homogenous, spherical components with equipartition sizes of 0.1
and 0.2 pc at 43 and 15 GHz, and with magnetic fields of 0.4 and 1 Gauss. VLBA
observations at 43 GHz confirm this double structure and these sizes. Time
scale arguments suggest that the emitting regions are shocks which are
continuously accelerating particles. This could be explained by a frustrated
jet scenario with very compact hotspots. Similar millimeter-peaked spectrum
(MPS) sources could have escaped our attention because of their low flux
density at typical survey frequencies and their strong variability.Comment: ApJ Letters, in press, (AAS)LaTeX, 3 figures, available at
http://www2.mpifr-bonn.mpg.de/staff/hfalcke/publications.html#iiizw2 or in a
few weeks at
http://www.mpifr-bonn.mpg.de/staff/falcke/publications.html#iiizw
Categorizing Health Outcomes and Efficacy of mHealth Apps for Persons With Cognitive Impairment: A Systematic Review
Background
Use of mobile health (mHealth) apps is growing at an exponential rate in the United States and around the world. Mild cognitive impairment (MCI), Alzheimer disease, and related dementias are a global health problem. Numerous mHealth interventions exist for this population, yet the effect of these interventions on health has not been systematically described.
Objective
The aim of this study is to catalog the types of health outcomes used to measure effectiveness of mHealth interventions and assess which mHealth interventions have been shown to improve the health of persons with MCI, Alzheimer disease, and dementia.
Methods
We searched 13 databases, including Ovid MEDLINE, PubMed, EMBASE, the full Cochrane Library, CINAHL, PsycINFO, Ei Compendex, IEEE Xplore, Applied Science & Technology Source, Scopus, Web of Science, ClinicalTrials.gov, and Google Scholar from inception through May 2017 for mHealth studies involving persons with cognitive impairment that were evaluated using at least one quantitative health outcome. Proceedings of the Annual ACM Conferences on Human Factors in Computing Systems, the ACM User Interface Software and Technology Symposium, and the IEEE International Symposium on Wearable Computers were searched in the ACM Digital Library from 2012 to 2016. A hand search of JMIR Publications journals was also completed in July 2017.
Results
After removal of duplicates, our initial search returned 3955 records. Of these articles, 24 met final inclusion criteria as studies involving mHealth interventions that measured at least one quantitative health outcome for persons with MCI, Alzheimer disease, and dementia. Common quantitative health outcomes included cognition, function, mood, and quality of life. We found that 21.2% (101/476) of the fully reviewed articles were excluded because of a lack of health outcomes. The health outcomes selected were observed to be inconsistent between studies. For those studies with quantitative health outcomes, more than half (58%) reported postintervention improvements in outcomes.
Conclusions
Results showed that many mHealth app interventions targeting those with cognitive impairment lack quantitative health outcomes as a part of their evaluation process and that there is a lack of consensus as to which outcomes to use. The majority of mHealth app interventions that incorporated health outcomes into their evaluation noted improvements in the health of persons with MCI, Alzheimer disease, and dementia. However, these studies were of low quality, leading to a grade C level of evidence. Clarification of the benefits of mHealth interventions for people with cognitive impairment requires more randomized controlled trials, larger numbers of participants, and trial designs that minimize bias.
Trial Registration
PROSPERO Registration: PROSPERO 2016:CRD42016033846; http://www.crd.york.ac.uk/PROSPERO/ display_record.asp?ID=CRD42016033846 (Archived by WebCite at http://www.webcitation.org/6sjjwnv1M
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