678 research outputs found
Very high energy gamma-rays and the Hubble parameter
A new method, based on the absorption of very high-energy gamma-rays by the
cosmic infrared background, is proposed to constrain the value of the Hubble
constant. As this value is both fundamental for cosmology and still not very
well measured, it is worth developing such alternative methods. Our lower limit
at the 68% confidence level is H0 > 74 km/s/Mpc, leading, when combined with
the HST results, to H0 ~ 76 km/s/Mpc. Interestingly, this value, which is
significantly higher than the usually considered one, is in exact agreement
with other independent approaches based on baryonic acoustic oscillations and
X-ray measurements. Forthcoming data from the experiments HESS-2 and CTA should
help improving those results. Finally, we briefly mention a plausible
correlation between absorption by the extragalactic background light and the
absence of observation of gamma-ray bursts (GRBs) at very high energies.Comment: Proc. of the 12th Marcel Grossmann meeting on general relativity. 3
pages, 1 figur
Baryonic acoustic oscillations simulations for the Large Synoptic Survey Telescope (LSST)
The baryonic acoustic oscillations are features in the spatial distribution
of the galaxies which, if observed at different epochs, probe the nature of the
dark energy. In order to be able to measure the parameters of the dark energy
equation of state to high precision, a huge sample of galaxies has to be used.
The Large Synoptic Survey Telescope will survey the optical sky with 6 filters
from 300nm and 1100nm, such that a catalog of galaxies with photometric
redshifts will be available for dark energy studies. In this article, we will
give a rough estimate of the impact of the photometric redshift uncertainties
on the computation of the dark energy parameter through the reconstruction of
the BAO scale from a simulated photometric catalog.Comment: 4 pages, 2 figures, 10th Rencontres de Blois proceedin
Research on electric heating of metals for thermal treatment Final report
Electric heat treatment process for aluminum and titanium aluminum vanadium alloy
Information coding with frequency of oscillations in Belousov-Zhabotinsky encapsulated disks
Information processing with an excitable chemical medium, like the Belousov-Zhabotinsky (BZ) reaction, is typically based on information coding in the presence or absence of excitation pulses. Here we present a new concept of Boolean coding that can be applied to an oscillatory medium. A medium represents the logical TRUE state if a selected region oscillates with a high frequency. If the frequency fails below a specified value, it represents the logical FALSE state. We consider a medium composed of disks encapsulating an oscillatory mixture of reagents, as related to our recent experiments with lipid-coated BZ droplets. We demonstrate that by using specific geometrical arrangements of disks containing the oscillatory medium one can perform logical operations on variables coded in oscillation frequency. Realizations of a chemical signal diode and of a single-bit memory with oscillatory disks are also discussed
The Sloan Lens ACS Survey. VIII. The relation between environment and internal structure of early-type galaxies
We study the relation between the internal structure of early-type galaxies
and their environment using 70 strong gravitational lenses from the Sloan ACS
Lens Survey. The Sloan database is used to determine two measures of
overdensity of galaxies around each lens: the projected number density of
galaxies inside the tenth nearest neighbor (\Sigma_{10}) and within a cone of
radius one h^{-1} Mpc (D_1). Our main results are: 1) The average overdensity
is somewhat larger than unity, consistent with lenses preferring overdense
environments as expected for massive early-type galaxies (12/70 lenses are in
known groups/clusters). 2) The distribution of overdensities is
indistinguishable from that of "twin" non-lens galaxies selected from SDSS to
have the same redshift and stellar velocity dispersion \sigma_*. Thus, within
our errors, lens galaxies are an unbiased population, and the SLACS results can
be generalized to the overall population of early-type galaxies. 3) Typical
contributions from external mass distribution are no more than a few per cent,
reaching 10-20% (~0.05-0.10 external convergence) only in the most extreme
overdensities. 4) No significant correlation between overdensity and slope of
the mass density profile of the lens is found. 5) Satellite galaxies (those
with a more luminous companion) have marginally steeper mass density profiles
than central galaxies (those without). This result suggests that tidal
stripping may affect the mass structure of early-type galaxies down to kpc
scales probed by strong lensing, when they fall into larger structures
[ABRIDGED].Comment: ApJ, in press; minor changes with respect to v
CO2 storage risk minimization through systematic identification and assessment of faults: a Williston Basin case study
AbstractThe Williston Basin is considered a tectonically stable area with only a few major inactive faults. Over the last 50 years, extensive hydrocarbon exploration in the basin has demonstrated that smaller faults do exist and closer evaluation is necessary to determine the nature of this faulting. An area near the town of Dickinson, North Dakota, has been identified as a potential location for CO2 storage/enhanced oil recovery. A thorough geologic assessment of the area has identified structural anomalies that may indicate the presence of faulting, which, in turn, may affect precise CO2 storage site selection
On designing observers for time-delay systems with nonlinear disturbances
This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2002 Taylor & Francis LtdIn this paper, the observer design problem is studied for a class of time-delay nonlinear systems. The system under consideration is subject to delayed state and non-linear disturbances. The time-delay is allowed to be time-varying, and the non-linearities are assumed to satisfy global Lipschitz conditions. The problem addressed is the design of state observers such that, for the admissible time-delay as well as non-linear disturbances, the dynamics of the observation error is globally exponentially stable. An effective algebraic matrix inequality approach is developed to solve the non-linear observer design problem. Specifically, some conditions for the existence of the desired observers are derived, and an explicit expression of desired observers is given in terms of some free parameters. A simulation example is included to illustrate the practical applicability of the proposed theory.The work of Z. Wang was supported in part by the University of Kaiserslautern of Germany and the Alexander von Humboldt Foundation of Germany
Impact of P2RX7 ablation on the morphological, mechanical and tissue
Duchenne muscular dystrophy (DMD) is an inherited, lethal disorder characterised by progressive muscle degeneration and associated bone abnormalities. We have previously demonstrated that P2RX7 purinergic receptors contribute to the pathogenesis of DMD, and found that P2RX7 ablation alleviated the severity of the disease. In this work we have used a dystrophic mdx mouse crossed with the global P2RX7 receptor to generate a knockout mouse (mdx/P2X7−/−), and compared its morphometric, mechanical and tissue properties against those of mdx, as well as the wild type (WT) and the P2RX7 knockout (P2X7−/-). Micro-computed tomography (µCT), three-point bending testing, scanning electron microscopy (SEM) and nano-indentation were utilised in the study. The bones were analysed at approximately 4 weeks of age to examine the impact of P2RX7 ablation on the bone properties during the acute disease phase, before muscle wasting is fully developed.
The results show that P2RX7 purinoceptor ablation has produced improvement or significant improvement in some of the morphological, the mechanical and the tissue properties of the dystrophic bones examined. Specifically, although the ablation produced smaller bones with significantly lower total cross-section area (Tt.Ar) and Second Moment of Area (SMA), significantly higher cortical bone area (Ct.Ar), cortical area fraction (Ct.Ar/Tt.Ar) and trabecular bone volume fraction (BV/TV) are found in the mdx/P2X7−/− mice than in any other types. Further, the mdx/P2X7−/− bones have relatively higher average flexural strength, work-to-fracture and significantly higher strain to failure compared with those of mdx, suggesting greater resistance to fracture. Indentation modulus, elasticity and creep are also significantly improved in the knockout cortical bones over those of mdx. These findings seem to suggest that specific pharmacological blockade of P2RX7 may improve dystrophic bones, with a potential for therapeutic application in the treatment of the disease
Design and Implementation of a Scalable, Automated, Semi-Permanent Seismic Array for Detecting CO2 Extent during Geologic CO2 Injection
A proof-of-concept demonstration using a scalable, automated, semipermanent, seismic array (SASSA) is being conducted to test a novel seismic method for detecting and tracking an injected CO2plume as it traverses discreet points within a reservoir in southeastern Montana at Bell Creek oil field which is undergoing commercial CO2enhanced oil recovery (EOR). This document serves to describe the technical design of the project infrastructure, the operational approach, corresponding data collection, and data-processing activities
Response Types and Factors Associated with Response Types to Biologic Therapies in Patients with Moderate-to-Severe Plaque Psoriasis from Two Randomized Clinical Trials.
This study aimed to understand treatment response dynamics, including factors associated with favorable response, among patients with moderate-to-severe psoriasis who received guselkumab, adalimumab, or secukinumab.
These post hoc analyses used data from the phase III clinical trials ECLIPSE and VOYAGE 1, which were conducted between September 2021 and November 2022. On the basis of absolute Psoriasis Area and Severity Index (aPASI) scores, patients were divided into short-term response types (SRT1-6, based on week 20-48 response) and long-term response types (LRT1-4, based on week 52-252 response). Response types (RTs) were based on aPASI cutoffs deemed clinically relevant by the investigators; SRT1/LRT1 were the most favorable response types. Baseline characteristics were compared across RTs, and logistic regression analyses established factors associated with SRT1/LRT1.
Overall, 1045, 662, and 272 patients were included in the ECLIPSE short-term, VOYAGE 1 short-term, and VOYAGE 1 long-term analyses, respectively. Mean age, body mass index (BMI), baseline aPASI score, and body surface area were lower in SRT1 than SRT6. In VOYAGE 1, adalimumab treatment, high BMI, and current/former smoking status resulted in less favorable responses. In the VOYAGE 1 long-term analysis, patients in LRT4 had the highest baseline aPASI score, were older, and were more often obese compared with other LRT groups. Regression analyses showed that SRT1 (both treatments) in VOYAGE 1 and ECLIPSE, and LRT1 (guselkumab group) in the VOYAGE 1 long-term analysis, were associated with week 16 aPASI response. In VOYAGE 1, SRT1 was associated with psoriasis duration and smoking status.
Early treatment response and baseline characteristics, including smoking, psoriasis duration, and obesity, may be associated with longer-term response to biologics.
ECLIPSE: NCT03090100, VOYAGE 1: NCT02207231
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