764 research outputs found
Ambiguity in the Determination of the Free Energy for a Model of the Circle Map
We consider a simple model to describe the widths of the mode locked
intervals for the critical circle map. Using two different partitions of the
rational numbers, based on Farey series and Farey tree levels respectively, we
calculate the free energy analytically at selected points for each partition.
It is found that the result of the calculation depends on the method of
partition. An implication of this is that the generalized dimensions are
different for each partition except when , i.e. only the Hausdorff
dimension is the same in each case.Comment: 14 page
Recapitulating the Bayesian framework for neurosurgical outpatient care and a cost-benefit analysis of telemedicine for socioeconomically disadvantaged patients in the Philippines during the pandemic
Objective: In the Philippines during recent months, a neurosurgical center that caters primarily to socioeconomically disadvantaged patients has encountered unprecedented changes in practice patterns brought about by the COVID-19 pandemic. In particular, the usual task of outpatient care has shifted to the telemedicine format, bringing along all of its attendant advantages and gargantuan challenges. The authors sought to determine the responsiveness of this telemedicine setup to the needs of their disadvantaged patients and explored the application of Bayesian inference to enhance the use of teleconsultation in daily clinical decision-making. Methods: The authors used the following methods to assess the telemedicine setup used in a low-resource setting during the pandemic: 1) a cross-sectional survey of patients who participated in a medical consultation via telemedicine during the 16-week period from March 16, 2020, to July 15, 2020; 2) a cost-benefit analysis of the use of telemedicine by patients; and 3) a case illustration of a Bayesian approach application unique to the teleconsultation scenario. Results: Of the 272 patient beneficiaries of telemedicine in a 16-week period, 57 responded to the survey. The survey responses regarding neurosurgical outpatient care through telemedicine yielded high ratings of utility for the patients and their caregivers. According to 64% of respondents, the affordability of the telemedicine setup also prevented them from borrowing money from others, among other adverse life events prevented. There were realized financial gains on the part of the patients in terms of cost savings and protection from further impoverishment. The benefit-cost ratio was 3.51 for the patients, signifying that the benefits outweighed the costs. An actual teleconsultation case vignette was reported that is meant to be instructive and contributory to the preparedness of the neurosurgeon on the provider end of the service delivery. Conclusions: Telemedicine holds promise as a viable and safe method for health service delivery during the pandemic. In the setting of a health system that is continually challenged by shortages of resources, this study shows that an effective telemedicine setup can come with high benefit-cost ratios and quality of care, along with the assurance of patient satisfaction. The potential for high-quality care can be enhanced by the inclusion of the Bayesian framework to the basic toolkit of remote clinical assessment. When confronted with choices in terms of differential diagnosis and tests, the rigor of a simple application of the Bayesian framework can minimize costs arising from uncertaintie
The Chandra Source Catalog
The Chandra Source Catalog (CSC) is a general purpose virtual X-ray
astrophysics facility that provides access to a carefully selected set of
generally useful quantities for individual X-ray sources, and is designed to
satisfy the needs of a broad-based group of scientists, including those who may
be less familiar with astronomical data analysis in the X-ray regime. The first
release of the CSC includes information about 94,676 distinct X-ray sources
detected in a subset of public ACIS imaging observations from roughly the first
eight years of the Chandra mission. This release of the catalog includes point
and compact sources with observed spatial extents <~ 30''. The catalog (1)
provides access to the best estimates of the X-ray source properties for
detected sources, with good scientific fidelity, and directly supports
scientific analysis using the individual source data; (2) facilitates analysis
of a wide range of statistical properties for classes of X-ray sources; and (3)
provides efficient access to calibrated observational data and ancillary data
products for individual X-ray sources, so that users can perform detailed
further analysis using existing tools. The catalog includes real X-ray sources
detected with flux estimates that are at least 3 times their estimated 1 sigma
uncertainties in at least one energy band, while maintaining the number of
spurious sources at a level of <~ 1 false source per field for a 100 ks
observation. For each detected source, the CSC provides commonly tabulated
quantities, including source position, extent, multi-band fluxes, hardness
ratios, and variability statistics, derived from the observations in which the
source is detected. In addition to these traditional catalog elements, for each
X-ray source the CSC includes an extensive set of file-based data products that
can be manipulated interactively.Comment: To appear in The Astrophysical Journal Supplement Series, 53 pages,
27 figure
Polygenic overlap between schizophrenia risk and antipsychotic response: a genomic medicine approach
Therapeutic treatments for schizophrenia do not alleviate symptoms for all patients and efficacy is limited by common, often severe, side-effects. Genetic studies of disease can identify novel drug targets, and drugs for which the mechanism has direct genetic support have increased likelihood of clinical success. Large-scale genetic studies of schizophrenia have increased the number of genes and gene sets associated with risk. We aimed to examine the overlap between schizophrenia risk loci and gene targets of a comprehensive set of medications to potentially inform and improve treatment of schizophrenia
Statistical Characterization of the Chandra Source Catalog
The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray
sources in a total area of ~0.75% of the entire sky, using data from ~3,900
separate ACIS observations of a multitude of different types of X-ray sources.
In order to maximize the scientific benefit of such a large, heterogeneous
data-set, careful characterization of the statistical properties of the
catalog, i.e., completeness, sensitivity, false source rate, and accuracy of
source properties, is required. Characterization efforts of other, large
Chandra catalogs, such as the ChaMP Point Source Catalog (Kim et al. 2007) or
the 2 Mega-second Deep Field Surveys (Alexander et al. 2003), while
informative, cannot serve this purpose, since the CSC analysis procedures are
significantly different and the range of allowable data is much less
restrictive. We describe here the characterization process for the CSC. This
process includes both a comparison of real CSC results with those of other,
deeper Chandra catalogs of the same targets and extensive simulations of
blank-sky and point source populations.Comment: To be published in the Astrophysical Journal Supplement Series (Fig.
52 replaced with a version which astro-ph can convert to PDF without issues.
A non-myeloablative chimeric mouse model accurately defines microglia and macrophage contribution in glioma.
Resident and peripherally-derived glioma associated microglia/macrophages (GAMM) play a key role in driving tumour progression, angiogenesis, invasion, and attenuating host immune responses. Differentiating these cells' origins is challenging and current pre-clinical models such as irradiation-based adoptive transfer, parabiosis and transgenic mice have limitations. We aimed to develop a novel non-myeloablative transplantation (NMT) mouse model that permits high levels of peripheral chimerism without blood-brain barrier (BBB) damage or brain infiltration prior to tumour implantation.NMT dosing was determined in C57BL/6J or Pep3/CD45.1 mice conditioned with concentrations of busulfan ranging from 25mg/kg to 125mg/kg. Donor haematopoietic cells labelled with eGFP or CD45.2 were injected via tail vein. Donor chimerism was measured in peripheral blood, bone marrow and spleen using flow cytometry. BBB integrity was assessed with anti-IgG and anti-fibrinogen antibodies. Immunocompetent chimerised animals were orthotopically implanted with murine glioma GL-261 cells. Central and peripheral cell contributions were assessed using immunohistochemistry and flow cytometry. GAMM subpopulation analysis of peripheral cells was performed using Ly6C/MHCII/MerTK/CD64.NMT achieves >80% haematopoietic chimerism by 12 weeks without BBB damage and normal life span. Bone marrow derived cells (BMDC) and peripheral macrophages accounted for approximately 45% of the GAMM population in GL-261 implanted tumours. Existing markers such as CD45 high/low proved inaccurate to determine central and peripheral populations while Ly6C/MHCII/MerTK/CD64 reliably differentiated GAMM subpopulations in chimerised and unchimerised mice.NMT is a powerful method for dissecting tumour microglia and macrophage subpopulations and can guide further investigation of BMDC subsets in glioma and neuro-inflammatory diseases. This article is protected by copyright. All rights reserved
Potentially inappropriate medication use in older adults with mild-moderate Alzheimer's disease:Prevalence and associations with adverse events
Aim: Potentially inappropriate medication (PIM) use is prevalent in older adults and is associated with adverse events, hospitalisation and mortality. We assessed the patterns and associations of PIM use in older adults with mild-to-moderate Alzheimer's Disease (AD), who may represent a particularly vulnerable group. Design: Analysis of data from NILVad, an 18-month Randomised Control Trial of Nilvadapine in mild-to-moderate AD. The v2 STOPP criteria were applied in duplicate to identify PIM use. Associations between PIM use and adverse events/unscheduled healthcare visits in addition to the associations between PIM use and AD progression were evaluated. Setting and Participants: 448 older adults with mild-to-moderate AD from 23 centres in nine European countries. Results: Of 448 participants (mean age: 72.56 ± 8.19 years), over half (55.8%) were prescribed a PIM with 30.1% being prescribed 2+ PIMs. The most frequent PIMs were (i) long-term benzodiazepines (11.6% N = 52/448), (ii) selective serotonin reuptake inhibitors without appropriate indication (11.1% N = 50/448), and (iii) Proton-Pump Inhibitors (PPIs) without appropriate indication (10.7% N = 48/448). Increasing number of PIMs was associated with a greater risk of adverse events (IRR 1.17, 1.13-1.19, P < 0.001), serious adverse events (IRR 1.27; 1.17-1.37, P < 0.001), unscheduled hospitalisations (IRR 1.16, 1.03-1.30, P = 0.016) and GP visits (IRR 1.22, 1.15-1.28, P < 0.001). PIM use was not associated with dementia progression. Conclusions and Implications: PIM use is highly prevalent in mild-to-moderate AD and is associated with adverse events and unscheduled healthcare utilisation. Further attention to de-prescribing in this vulnerable group is warranted
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