549 research outputs found
Resonance between Noise and Delay
We propose here a stochastic binary element whose transition rate depends on
its state at a fixed interval in the past. With this delayed stochastic
transition this is one of the simplest dynamical models under the influence of
``noise'' and ``delay''. We demonstrate numerically and analytically that we
can observe resonant phenomena between the oscillatory behavior due to noise
and that due to delay.Comment: 4 pages, 5 figures, submitted to Phys.Rev.Lett Expanded and Added
Reference
Creating massive entanglement of Bose condensed atoms
We propose a direct, coherent coupling scheme that can create massively
entangled states of Bose-Einstein condensed atoms. Our idea is based on an
effective interaction between two atoms from coherent Raman processes through a
(two atom) molecular intermediate state. We compare our scheme with other
recent proposals for generation of massive entanglement of Bose condensed
atoms.Comment: 5 pages, 3 figures; Updated figure 3(a), original was "noisy
Natural images from the birthplace of the human eye
Here we introduce a database of calibrated natural images publicly available
through an easy-to-use web interface. Using a Nikon D70 digital SLR camera, we
acquired about 5000 six-megapixel images of Okavango Delta of Botswana, a
tropical savanna habitat similar to where the human eye is thought to have
evolved. Some sequences of images were captured unsystematically while
following a baboon troop, while others were designed to vary a single parameter
such as aperture, object distance, time of day or position on the horizon.
Images are available in the raw RGB format and in grayscale. Images are also
available in units relevant to the physiology of human cone photoreceptors,
where pixel values represent the expected number of photoisomerizations per
second for cones sensitive to long (L), medium (M) and short (S) wavelengths.
This database is distributed under a Creative Commons Attribution-Noncommercial
Unported license to facilitate research in computer vision, psychophysics of
perception, and visual neuroscience.Comment: Submitted to PLoS ON
Myocardial ischemic-fibrotic injury after human heart transplantation is associated with increased progression of vasculopathy, decreased cellular rejection and poor long-term outcome
AbstractObjectivesWe sought to assess the influence of peritransplant ischemia and fibrosis on the development of allograft vasculopathy, acute cellular rejection and long-term outcome.BackgroundAllograft vasculopathy is a common long-term complication of cardiac transplantation. One of the potential risk factors is peritransplant allograft ischemia.MethodsOne hundred forty heart transplant recipients had baseline and one-year intravascular ultrasound analysis done to assess the progression of allograft vasculopathy. Serial endomyocardial biopsies were evaluated for cellular rejection, vascular rejection, ischemia and fibrosis. Based on histology, patients were classified into one of the following groups: nonischemic (n = 32), ischemia (n = 24), fibrosis (n = 62) or vascular rejection (n = 22). Three-color flow cytometry crossmatching (FCXM) was used to assess donor-specific human lymphocyte antigens (HLA) sensitization. Long-term outcome of patients in each group was assessed by estimating incidence of graft failure or deaths over a seven-year follow up.ResultsPatients in the fibrosis group had the lowest incidence of donor-specific HLA sensitization (40%, p = 0.008) and lowest average episodes of cellular rejection (1.7 ± 1.4, p = 0.04), but they had increased coronary vasculopathy progression (change in coronary intimal thickness = 0.59 ± 0.28 mm, p < 0.0001) and poor seven-year event-free survival (49%, p = 0.01).ConclusionsThe development of fibrosis after cardiac transplantation is associated with advanced coronary vasculopathy, although a low incidence of acute cellular rejection is noted, suggesting the presence of nonimmune mechanisms in mediating the pathogenesis of allograft vasculopathy
VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196
We present results from multiwavelength observations of the BL Lacertae
object 1ES 1741+196, including results in the very-high-energy -ray
regime using the Very Energetic Radiation Imaging Telescope Array System
(VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is
well-modelled by a power law with a spectral index of
. The integral flux above 180
GeV is
m s, corresponding to 1.6% of the Crab Nebula flux on average.
The multiwavelength spectral energy distribution of the source suggests that
1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The
observations analysed in this paper extend over a period of six years, during
which time no strong flares were observed in any band. This analysis is
therefore one of the few characterizations of a blazar in a non-flaring state.Comment: 8 pages, 5 figures. Accepted for publication in MNRA
Investigating the TeV Morphology of MGRO J1908+06 with VERITAS
We report on deep observations of the extended TeV gamma-ray source MGRO
J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory.
Previously, the TeV emission has been attributed to the pulsar wind nebula
(PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a
significance level of 14 standard deviations (14 sigma) and measure a photon
index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended,
covering the region near PSR J1907+0602 and also extending towards SNR
G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension
has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to
other TeV PWNe of similar age in which the TeV spectrum softens with distance
from the pulsar, the TeV spectrum measured near the pulsar location is
consistent with that measured at a position near the rim of G40.5--0.5, 0.33
degrees away.Comment: To appear in ApJ, 8 page
Search for axion-like particles through nuclear Primakoff production using the GlueX detector
We report on the results of the first search for the production of axion-like
particles (ALP) via Primakoff production on nuclear targets using the GlueX
detector. This search uses an integrated luminosity of 100
pbnucleon on a C target, and explores the mass region of 200
< < 450 MeV via the decay . This mass range is
between the and masses, which enables the use of the measured
production rate to obtain absolute bounds on the ALP production with
reduced sensitivity to experimental luminosity and detection efficiency. We
find no evidence for an ALP, consistent with previous searches in the quoted
mass range, and present limits on the coupling on the scale of (1 TeV). We
further find that the ALP production limit we obtain is hindered by the peaking
structure of the non-target-related dominant background in GlueX, which we
treat by using data on He to estimate and subtract these backgrounds. We
comment on how this search can be improved in a future higher-statistics
dedicated measurement
Polarisation of a T-helper cell immune response by activation of dendritic cells with CpG-containing oligonucleotides: a potential therapeutic regime for bladder cancer immunotherapy
Intravesical bacillus Calmette-Guerin (BCG) is a treatment for transitional cell carcinoma (TCC) and carcinoma in situ (cis) of the urinary bladder, but some patients remain refractory. The mechanism of cancer clearance is not known, but T cells are thought to play a contributory role. Tissue dendritic cells (DCs) are known to initiate antigen-specific immune responses following activation of receptors, which recognise molecular patterns on the surface of microorganisms. A family of these receptors, the toll-like receptors (TLRs), are also crucial for activating DC to produce cytokines that polarise the T-cell response towards a T helper (Th)1 or Th2 phenotype. This study compared the potential of intact BCG to activate DC with that of the defined TLR4 ligand lipopolysaccharide (LPS) and the TLR9 ligand CpG-oligonucleotide. It was found that all three stimuli efficiently activated normal DC, but cells expressing a mutant TLR4 responded poorly to stimulation with LPS. Importantly, stimulation with BCG induced both IL-12 and IL-10, suggesting subsequent development of a poorly focused T-cell immune response containing both Th1 and Th2 immune function. By contrast, LPS- and CpG-oligonucleotides induced only IL-12, indicating the potential to produce a Th1 response, which is likely to clear cancer most efficiently. Given the toxicity of LPS, our data suggest that CpG-oligonucleotides may be beneficial for intravesical therapy of bladder cancer
Effects of Distillers Dried Grains with Solubles Sources and Soybean Meal Level on Growth Performance of Late Nursery Pigs
Two experiments were conducted to determine the effects of distillers dried grains with solubles (DDGS) source and soybean meal (SBM) level on growth performance of late nursery pigs. A total of 1,064 and 1,011 pigs (PIC 280 × 1050), initially 23.1 and 24.1 lb body weight (BW), were used in Exp. 1 and 2, respectively, with 21 to 27 pigs per pen. For approximately 21 days after weaning, pigs were fed common phase 1 and 2 diets. Then, pens were assigned to treatments in a randomized complete block design. There were 6 treatments in each experiment with 7 pens per treatment. Treatments 1 to 5 were replicated in Exp. 1 and 2, whereas treatment 6 was fed only in Exp. 1 and treatment 7 was fed only in Exp. 2. Treatments 1 to 3 consisted of diets with 23% conventional DDGS (Valero, Aurora, SD) and 21, 27, or 35% SBM. Treatments 4 and 5 were corn-SBM-based diets with 27 or 35% SBM. Treatment 6 consisted of a corn-SBM-based diet with 20% high protein DDGS (HP DDGS; Purestream 40, Lincolnway Energy, LLC, Nevada, IA) replacing the 23% conventional DDGS with the same amount of SBM (21%) as treatment 1 and same neutral detergent fiber (NDF) as treatment 2. Finally, treatment 7 consisted of a diet similar to treatment 2 but with 23% Lincolnway DDGS (Lincolnway Energy, LLC, Nevada, IA) replacing the 23% conventional DDGS. Data were analyzed with the GLIMMIX procedure of SAS. There was no evidence for treatment × experiment interactions, thus data from treatments 1 to 5 were combined. In Exp. 1, pigs fed diets containing HP DDGS had decreased (P \u3c 0.01) average daily gain (ADG) and poorer (P \u3c 0.01) feed-to-gain ratio (F/G) compared to pigs fed diets with conventional DDGS at the same NDF level, conventional DDGS at the same SBM level, or corn-SBM diet. In Exp. 2, there was no evidence for differences (P \u3e 0.10) in performance of pigs fed diets with Lincolnway DDGS or conventional DDGS. Feeding diets with 23% conventional DDGS decreased (P = 0.033) average daily feed intake (ADFI) and improved (P = 0.033) F/G compared to corn-SBM-based diets. Finally, ADG increased (linear, P = 0.001) and F/G improved (quadratic, P = 0.007) as SBM level increased from 21 to 35%. In conclusion, decreased growth performance indicates that the nutrient profile of the HP DDGS may have been overestimated. The net energy of conventional and Lincolnway DDGS seemed to be underestimated due to the improved F/G compared to corn-SBM diets. Finally, feeding diets with increasing SBM resulted in improved growth performance in late nursery pigs
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