250 research outputs found
Auditing an Academic Library Book Collection
Librarians may use attribute sampling to estimate the maximum portion of a population having an attribute of interest. Advantages of the technique are that the user may examine a very small portion of the population and make an estimate with very low but measurable risk of misstatement
Tubular free by cyclic groups act freely on CAT(0) cube complexes
AbstractWe identify when a tubular group (the fundamental group of a ûnite graph of groups with ℤ2 vertex and ℤ edge groups) is free by cyclic and show, using Wise’s equitable sets criterion, that every tubular free by cyclic group acts freely on a CAT(0) cube complex.</jats:p
Optimized Multi-Frequency Spectra for Applications in Radiative Feedback and Cosmological Reionization
The recent implementation of radiative transfer algorithms in numerous
hydrodynamics codes has led to a dramatic improvement in studies of feedback in
various astrophysical environments. However, because of methodological
limitations and computational expense, the spectra of radiation sources are
generally sampled at only a few evenly-spaced discrete emission frequencies.
Using one-dimensional radiative transfer calculations, we investigate the
discrepancies in gas properties surrounding model stars and accreting black
holes that arise solely due to spectral discretization. We find that even in
the idealized case of a static and uniform density field, commonly used
discretization schemes induce errors in the neutral fraction and temperature by
factors of two to three on average, and by over an order of magnitude in
certain column density regimes. The consequences are most severe for radiative
feedback operating on large scales, dense clumps of gas, and media consisting
of multiple chemical species. We have developed a method for optimally
constructing discrete spectra, and show that for two test cases of interest,
carefully chosen four-bin spectra can eliminate errors associated with
frequency resolution to high precision. Applying these findings to a fully
three-dimensional radiation-hydrodynamic simulation of the early universe, we
find that the HII region around a primordial star is substantially altered in
both size and morphology, corroborating the one-dimensional prediction that
discrete spectral energy distributions can lead to sizable inaccuracies in the
physical properties of a medium, and as a result, the subsequent evolution and
observable signatures of objects embedded within it.Comment: 15 pages, 13 figures, 2 tables, accepted for publication in the
Astrophysical Journa
Solving the Supersymmetric Flavor Problem with Radiatively Generated Mass Hierarchies
The supersymmetric flavor problem may be solved if the first and second
generation scalars are heavy (with multi-TeV masses) and scalars with large
Higgs couplings are light (with sub-TeV masses). We show that such an inverted
spectrum may be generated radiatively; that is, from initial conditions where
all scalar masses are multi-TeV at some high scale, those with large Higgs
couplings may be driven asymptotically to the weak scale in the infra-red. The
lightness of third generation scalars is therefore a direct consequence of the
heaviness of third generation fermions, and fine-tuning is avoided even though
the fundamental scale of the soft supersymmetry breaking parameters is
multi-TeV. We investigate this possibility in the framework of the usual Yukawa
quasi-fixed point solutions. The required high scale boundary conditions are
found to be simple and highly predictive. This scenario also alleviates the
supersymmetric CP and Polonyi problems.Comment: 18 pages, 3 figures; typos corrected, refs added, conforms to
published versio
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Oropouche virus cases identified in Ecuador using an optimised qRT-PCR informed by metagenomic sequencing.
Oropouche virus (OROV) is responsible for outbreaks of Oropouche fever in parts of South America. We recently identified and isolated OROV from a febrile Ecuadorian patient, however, a previously published qRT-PCR assay did not detect OROV in the patient sample. A primer mismatch to the Ecuadorian OROV lineage was identified from metagenomic sequencing data. We report the optimisation of an qRT-PCR assay for the Ecuadorian OROV lineage, which subsequently identified a further five cases in a cohort of 196 febrile patients. We isolated OROV via cell culture and developed an algorithmically-designed primer set for whole-genome amplification of the virus. Metagenomic sequencing of the patient samples provided OROV genome coverage ranging from 68-99%. The additional cases formed a single phylogenetic cluster together with the initial case. OROV should be considered as a differential diagnosis for Ecuadorian patients with febrile illness to avoid mis-diagnosis with other circulating pathogens
BACE1 activity impairs neuronal glucose oxidation:rescue by beta-hydroxybutyrate and lipoic acid
Glucose hypometabolism and impaired mitochondrial function in neurons have been suggested to play early and perhaps causative roles in Alzheimer's disease (AD) pathogenesis. Activity of the aspartic acid protease, beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), responsible for beta amyloid peptide generation, has recently been demonstrated to modify glucose metabolism. We therefore examined, using a human neuroblastoma (SH-SY5Y) cell line, whether increased BACE1 activity is responsible for a reduction in cellular glucose metabolism. Overexpression of active BACE1, but not a protease-dead mutant BACE1, protein in SH-SY5Y cells reduced glucose oxidation and the basal oxygen consumption rate, which was associated with a compensatory increase in glycolysis. Increased BACE1 activity had no effect on the mitochondrial electron transfer process but was found to diminish substrate delivery to the mitochondria by inhibition of key mitochondrial decarboxylation reaction enzymes. This BACE1 activity-dependent deficit in glucose oxidation was alleviated by the presence of beta hydroxybutyrate or α-lipoic acid. Consequently our data indicate that raised cellular BACE1 activity drives reduced glucose oxidation in a human neuronal cell line through impairments in the activity of specific tricarboxylic acid cycle enzymes. Because this bioenergetic deficit is recoverable by neutraceutical compounds we suggest that such agents, perhaps in conjunction with BACE1 inhibitors, may be an effective therapeutic strategy in the early-stage management or treatment of AD
1958: Abilene Christian College Bible Lectures - Full Text
“GOD”
Being the
Abilene Christian College Annual
Bible Lectures
1958
Price: $3.00
Published by
FIRM FOUNDATION PUBLISHING HOUSE
Box 77 Austin, Texa
Methylphenidate Attenuates Limbic Brain Inhibition after Cocaine-Cues Exposure in Cocaine Abusers
Dopamine (phasic release) is implicated in conditioned responses. Imaging studies in cocaine abusers show decreases in striatal dopamine levels, which we hypothesize may enhance conditioned responses since tonic dopamine levels modulate phasic dopamine release. To test this we assessed the effects of increasing tonic dopamine levels (using oral methylphenidate) on brain activation induced by cocaine-cues in cocaine abusers. Brain metabolism (marker of brain function) was measured with PET and 18FDG in 24 active cocaine abusers tested four times; twice watching a Neutral video (nature scenes) and twice watching a Cocaine-cues video; each video was preceded once by placebo and once by methylphenidate (20 mg). The Cocaine-cues video increased craving to the same extent with placebo (68%) and with methylphenidate (64%). In contrast, SPM analysis of metabolic images revealed that differences between Neutral versus Cocaine-cues conditions were greater with placebo than methylphenidate; whereas with placebo the Cocaine-cues decreased metabolism (p<0.005) in left limbic regions (insula, orbitofrontal, accumbens) and right parahippocampus, with methylphenidate it only decreased in auditory and visual regions, which also occurred with placebo. Decreases in metabolism in these regions were not associated with craving; in contrast the voxel-wise SPM analysis identified significant correlations with craving in anterior orbitofrontal cortex (p<0.005), amygdala, striatum and middle insula (p<0.05). This suggests that methylphenidate's attenuation of brain reactivity to Cocaine-cues is distinct from that involved in craving. Cocaine-cues decreased metabolism in limbic regions (reflects activity over 30 minutes), which contrasts with activations reported by fMRI studies (reflects activity over 2–5 minutes) that may reflect long-lasting limbic inhibition following activation. Studies to evaluate the clinical significance of methylphenidate's blunting of cue-induced limbic inhibition may help identify potential benefits of this medication in cocaine addiction
Examining Associations Between Smartphone Use and Clinical Severity in Frontotemporal Dementia: Proof-of-Concept Study
BackgroundFrontotemporal lobar degeneration (FTLD) is a leading cause of dementia in individuals aged <65 years. Several challenges to conducting in-person evaluations in FTLD illustrate an urgent need to develop remote, accessible, and low-burden assessment techniques. Studies of unobtrusive monitoring of at-home computer use in older adults with mild cognitive impairment show that declining function is reflected in reduced computer use; however, associations with smartphone use are unknown.ObjectiveThis study aims to characterize daily trajectories in smartphone battery use, a proxy for smartphone use, and examine relationships with clinical indicators of severity in FTLD.MethodsParticipants were 231 adults (mean age 52.5, SD 14.9 years; n=94, 40.7% men; n=223, 96.5% non-Hispanic White) enrolled in the Advancing Research and Treatment of Frontotemporal Lobar Degeneration (ARTFL study) and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS study) Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) Mobile App study, including 49 (21.2%) with mild neurobehavioral changes and no functional impairment (ie, prodromal FTLD), 43 (18.6%) with neurobehavioral changes and functional impairment (ie, symptomatic FTLD), and 139 (60.2%) clinically normal adults, of whom 55 (39.6%) harbored heterozygous pathogenic or likely pathogenic variants in an autosomal dominant FTLD gene. Participants completed the Clinical Dementia Rating plus National Alzheimer's Coordinating Center Frontotemporal Lobar Degeneration Behavior and Language Domains (CDR+NACC FTLD) scale, a neuropsychological battery; the Neuropsychiatric Inventory; and brain magnetic resonance imaging. The ALLFTD Mobile App was installed on participants' smartphones for remote, passive, and continuous monitoring of smartphone use. Battery percentage was collected every 15 minutes over an average of 28 (SD 4.2; range 14-30) days. To determine whether temporal patterns of battery percentage varied as a function of disease severity, linear mixed effects models examined linear, quadratic, and cubic effects of the time of day and their interactions with each measure of disease severity on battery percentage. Models covaried for age, sex, smartphone type, and estimated smartphone age.ResultsThe CDR+NACC FTLD global score interacted with time on battery percentage such that participants with prodromal or symptomatic FTLD demonstrated less change in battery percentage throughout the day (a proxy for less smartphone use) than clinically normal participants (P<.001 in both cases). Additional models showed that worse performance in all cognitive domains assessed (ie, executive functioning, memory, language, and visuospatial skills), more neuropsychiatric symptoms, and smaller brain volumes also associated with less battery use throughout the day (P<.001 in all cases).ConclusionsThese findings support a proof of concept that passively collected data about smartphone use behaviors associate with clinical impairment in FTLD. This work underscores the need for future studies to develop and validate passive digital markers sensitive to longitudinal clinical decline across neurodegenerative diseases, with potential to enhance real-world monitoring of neurobehavioral change
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