1,875 research outputs found
Nuclear spin driven quantum relaxation in LiY_0.998Ho_0.002F_4
Staircase hysteresis loops of the magnetization of a LiY_0.998Ho_0.002F_4
single crystal are observed at subkelvin temperatures and low field sweep
rates. This behavior results from quantum dynamics at avoided level crossings
of the energy spectrum of single Ho^{3+} ions in the presence of hyperfine
interactions. Enhanced quantum relaxation in constant transverse fields allows
the study of the relative magnitude of tunnel splittings. At faster sweep
rates, non-equilibrated spin-phonon and spin-spin transitions, mediated by weak
dipolar interactions, lead to magnetization oscillations and additional steps.Comment: 5 pages, 5 eps figures, using RevTe
High-resolution Near-Infrared Images and Models of the Circumstellar Disk in HH 30
We present Hubble Space Telescope (HST) Near-Infrared Camera and Multi-object
Spectrometer (NICMOS) observations of the reflection nebulosity associated with
the T Tauri star HH 30. The images show the scattered light pattern
characteristic of a highly inclined, optically thick disk with a prominent
dustlane whose width decreases with increasing wavelength. The reflected
nebulosity exhibits a lateral asymmetry in the upper lobe on the opposite side
to that reported in previously published Wide Field Planetary Camera 2 (WFPC2)
images. The radiation transfer model which most closely reproduces the data has
a flared accretion disk with dust grains larger than standard interstellar
medium grains by a factor of approximately 2.1. A single hotspot on the stellar
surface provides the necessary asymmetry to fit the images and is consistent
with previous modeling of the light curve and images. Photometric analysis
results in an estimated extinction of Av>~80; however, since the photometry
measures only scattered light rather than direct stellar flux, this a lower
limit. The radiative transfer models require an extinction of Av = 7,900.Comment: Accepted for publication in Ap.
Control of food intake and meal patterns in monkeys
Feeding patterns have been studied in 10 adult male rhesus monkeys (Macaca mulatta) adapted to primate restraint chairs for physiological studies. Using an automated computer-monitored liquid diet feeding system, feeding behavior was studied under 8 hour and 24 hour feeding schedules. Calorie/kg intake was significantly reduced with the 8 hour schedule (pp>0.10). Meal size was negatively correlated with meal frequency across monkeys, but not within monkeys. Although monkeys ingested 78% of their voluntary intake during the light hours, there was no difference in meal size, meal duration, or rate of feeding between light and dark periods. With feeding restricted to 8 hours during the light period, meal size was positively correlated with the length of the interval preceding the meal in 4 of 6 monkeys, and meal size was also positively correlated with length of the postmeal interval in 3 of 6 monkeys. In contrast, 24 hour ad lib fed monkeys showed no relationship between premeal interval and subsequent meal size, but a positive correlation between meal size and postmeal interval in 3 of 4 monkeys. We conclude that feeding schedule or deprivation state may alter the relative roles of "hunger" and "satiety" signals in regulating food intake amounts and patterns.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24222/1/0000481.pd
18F-fluorothymidine (FLT)-PET and diffusion-weighted MRI for early response evaluation in patients with small cell lung cancer:a pilot study
On the Approach to the Equilibrium and the Equilibrium Properties of a Glass-Forming Model
In this note we apply some theoretical predictions that arise in the mean
field framework for a large class of infinite range models to structural
glasses and we present a first comparison of these predictions with numerical
results.Comment: 22 pages, 15 figure
Efficacy and safety of cotadutide, a dual glucagon-like peptide-1 and glucagon receptor agonist, in a randomized phase 2a study of patients with type 2 diabetes and chronic kidney disease
AIM: To assess the efficacy, safety and tolerability of cotadutide in patients with type 2 diabetes mellitus and chronic kidney disease. MATERIALS AND METHODS: In this phase 2a study (NCT03550378), patients with body mass index 25‐45 kg/m(2), estimated glomerular filtration rate 30‐59 ml/min/1.73 m(2) and type 2 diabetes [glycated haemoglobin 6.5‐10.5% (48‐91 mmol/mol)] controlled with insulin and/or oral therapy combination, were randomized 1:1 to once‐daily subcutaneous cotadutide (50‐300 μg) or placebo for 32 days. The primary endpoint was plasma glucose concentration assessed using a mixed‐meal tolerance test. RESULTS: Participants receiving cotadutide (n = 21) had significant reductions in the mixed‐meal tolerance test area under the glucose concentration‐time curve (–26.71% vs. +3.68%, p < .001), more time in target glucose range on continuous glucose monitoring (+14.79% vs. –21.23%, p = .001) and significant reductions in absolute bodyweight (–3.41 kg vs. –0.13 kg, p < .001) versus placebo (n = 20). In patients with baseline micro‐ or macroalbuminuria (n = 18), urinary albumin‐to‐creatinine ratios decreased by 51% at day 32 with cotadutide versus placebo (p = .0504). No statistically significant difference was observed in mean change in estimated glomerular filtration rate between treatments. Mild/moderate adverse events occurred in 71.4% of participants receiving cotadutide and 35.0% receiving placebo. CONCLUSIONS: We established the efficacy of cotadutide in this patient population, with significantly improved postprandial glucose control and reduced bodyweight versus placebo. Reductions in urinary albumin‐to‐creatinine ratios suggest potential benefits of cotadutide on kidney function, supporting further evaluation in larger, longer‐term clinical trials
The Spectral Energy Distribution of HH30 IRS: Constraining The Circumstellar Dust Size Distribution
We present spectral energy distribution (SED) models for the edge-on
classical T Tauri star HH30 IRS that indicate dust grains have grown to larger
than 50 microns within its circumstellar disk. The disk geometry and
inclination are known from previous modeling of multiwavelength Hubble Space
Telescope images and we use the SED to constrain the dust size distribution.
Model spectra are shown for different circumstellar dust models: a standard ISM
mixture and larger grain models. As compared to ISM grains, the larger dust
grain models have a shallower wavelength dependent opacity. Models with the
larger dust grains provide a good match to the currently available data, but
mid and far-IR observations are required to more tightly constrain the dust
size distribution. The accretion luminosity in our models is L_acc<0.2 L_star
corresponding to an accretion rate of 4E-9M_sun/yr. Dust size distributions
that are simple power-law extensions (i.e., no exponential cutoff) yield
acceptable fits to the optical/near-IR but too much emission at mm wavelengths
and require larger disk masses. Such a simple size distribution would not be
expected in an environment such as the disk of HH30 IRS, particularly over such
a large range in grain sizes. However, its ability to adequately characterize
the grain populations may be determined from more complete observational
sampling of the SED in the mid to far-IR.Comment: ApJ Accepte
(Anti)Proton and Pion Source Sizes and Phase Space Densities in Heavy Ion Collisions
NA44 has measured mid-rapidity deuteron spectra from AA collisions at
sqrt{s}=18GeV/A at the CERN SPS. Combining these spectra with published proton,
antiproton and antideuteron data allows us to calculate, within a coalescence
framework, proton and antiproton source sizes and phase space densities. These
results are compared to pion source sizes and densities, pA results and to
lower energy (AGS) data. The antiproton source is larger than the proton source
at sqrt{s}=18GeV/A. The phase space densities of pions and protons are not
constant but grow with system size. Both pi+ and proton radii decrease with
transverse mass and increase with sqrt{s}. Pions and protons do not freeze-out
independently. The nature of their interaction changes as sqrt{s}, and the
pion/proton ratio increases.Comment: 4 pages, Latex 2.09, 3 eps figures. Changes for January 2001. The
proton source size is now calculated assuming a more realistic Hulthen,
rather than Gaussian, wavefunction. A new figure shows the effect of this
change which is important for small radii. A second new figure shows the
results of RQMD calculations of the proton source size and phase density.
Because of correlations between position and momentum coalesence does not
show the full proton source size. The paper has been streamlined and
readability improve
Characterisation of the Immunophenotype of Dogs with Primary Immune-Mediated Haemolytic Anaemia
Immune-mediated haemolytic anaemia (IMHA) is reported to be the most common autoimmune disease of dogs, resulting in significant morbidity and mortality in affected animals. Haemolysis is caused by the action of autoantibodies, but the immunological changes that result in their production have not been elucidated.To investigate the frequency of regulatory T cells (Tregs) and other lymphocyte subsets and to measure serum concentrations of cytokines and peripheral blood mononuclear cell expression of cytokine genes in dogs with IMHA, healthy dogs and dogs with inflammatory diseases.19 dogs with primary IMHA, 22 dogs with inflammatory diseases and 32 healthy control dogs.Residual EDTA-anti-coagulated blood samples were stained with fluorophore-conjugated monoclonal antibodies and analysed by flow cytometry to identify Tregs and other lymphocyte subsets. Total RNA was also extracted from peripheral blood mononuclear cells to investigate cytokine gene expression, and concentrations of serum cytokines (interleukins 2, 6 10, CXCL-8 and tumour necrosis factor α) were measured using enhanced chemiluminescent assays. Principal component analysis was used to investigate latent variables that might explain variability in the entire dataset.There was no difference in the frequency or absolute numbers of Tregs among groups, nor in the proportions of other lymphocyte subsets. The concentrations of pro-inflammatory cytokines were greater in dogs with IMHA compared to healthy controls, but the concentration of IL-10 and the expression of cytokine genes did not differ between groups. Principal component analysis identified four components that explained the majority of the variability in the dataset, which seemed to correspond to different aspects of the immune response.The immunophenotype of dogs with IMHA differed from that of dogs with inflammatory diseases and from healthy control dogs; some of these changes could suggest abnormalities in peripheral tolerance that permit development of autoimmune disease. The frequency of Tregs did not differ between groups, suggesting that deficiency in the number of these cells is not responsible for development of IMHA
Authigenic carbonates from the Cascadia subduction zone and their relation to gas hydrate stability
Authigenic carbonates are intercalated with massive gas hydrates in sediments of the Cascadia margin. The deposits were recovered from the uppermost 50 cm of sediments on the southern summit of the Hydrate Ridge during the RV Sonne cruise SO110. Two carbonate lithologies that differ in chemistry, mineralogy, and fabric make up these deposits. Microcrystalline high-magnesium calcite (14 to 19 mol% MgCO3) and aragonite are present in both semiconsolidated sediments and carbonate-cemented clasts. Aragonite occurs also as a pure phase without sediment impurities. It is formed by precipitation in cavities as botryoidal and isopachous aggregates within pure white, massive gas hydrate. Variations in oxygen isotope values of the carbonates reflect the mineralogical composition and define two end members: a Mg-calcite with δ18O =4.86‰ PDB and an aragonite with δ18O =3.68‰ PDB. On the basis of the ambient bottom-water temperature and accepted equations for oxygen isotope fractionation, we show that the aragonite phase formed in equilibrium with its pore-water environment, and that the Mg-calcite appears to have precipitated from pore fluids enriched in 18O. Oxygen isotope enrichment probably originates from hydrate water released during gas-hydrate destabilization
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