Commensurations and Metric Properties of Houghton's Groups

We describe the automorphism groups and the abstract commensurators of Houghton's groups. Then we give sharp estimates for the word metric of these groups and deduce that the commensurators embed into the corresponding quasi-isometry groups. As a further consequence, we obtain that the Houghton group on two rays is at least quadratically distorted in those with three or more rays

Reconstruction of the Free Energy in the Metastable Region using the Path Ensemble

By quenching into the metastable region of the three-dimensional Ising model, we investigate the paths that the magnetization (energy) takes as a function of time. We accumulate the magnetization (energy) paths into time-dependent distributions from which we reconstruct the free energy as a function of the magnetic field, temperature and system size. From the reconstructed free energy, we obtain the free energy barrier that is associated with the transition from a metastable state to the stable equilibrium state. Although mean-field theory predicts a sharp transition between the metastable and the unstable region where the free energy barrier is zero, the results for the nearest-neighbour Ising model show that the free energy barrier does not go zero

The effect of working parameters upon elastohydrodynamic film thickness under periodic load variation

There are a number of widely used machine components, such as rolling element bearings, gears and cams, which operate in the lubrication regime known as Elastohydrodynamics (EHD), where lubricant film thickness is governed by hydrodynamic action of convergent geometry, elastic deformation between non-conformal contacting surfaces, and the increase of lubricant viscosity with pressure. Variable loading conditions occur not only in all the machine components mentioned above, but also in natural joints such as hip or knee joints of humans or many vertebrates. Experimental studies of the behaviour of EHD films under variable loading are scarce and to authors’ knowledge systematic studies of the evolution of lubricant film thickness in EHD contacts subjected to forced harmonic variation of load are even less common. The aim of the present study is to explore the effect of load amplitude on the EHD film behaviour. This is done in alternating cycles with the load varying about a fixed, preset value at various amplitudes. Experimental results are compared with a simple theoretical analysis based on the speed of change of contact’s dimensions, a semi-analytical solution which includes both speed variation and squeeze effect, and finally with a full numerical solution

TESTING FOR DIFFERENTIAL EFFECTS OF FOREST FIRES ON HIKING AND MOUNTAIN BIKING DEMAND AND BENEFITS

Surveys of visitors to National Forests in Colorado were conducted to determine whether different fire ages and presence of crown fires have different effects on hiking and mountain biking recreation visits and benefits. Actual and intended behavior data were combined using a count-data travel cost model. The intended behavior trip questions asked about changes in number of trips due to the presence of a high-intensity crown fire, prescribed fire, and a 20-year-old high-intensity fire at the area respondents were visiting. Using the estimated recreation demand function, years since a non-crown fire had statistically significant positive effect on the trip demand of hikers. In contrast, presence of crown fires had no statistically significant effect on the quantity of hiker trips, but had a significant and negative effect on mountain biking trips. Crown fires also had a large effect on the value per trip, with crown fires increasing the value per hiking trip but lowering the value per mountain biking trip.Resource /Energy Economics and Policy,

Lattice Modeling of Early-Age Behavior of Structural Concrete.

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential

Development and Test of High Temperature Surface Acoustic Wave Gas Sensors

The demand for sensors in hostile environments, such as power plant environments, exhaust systems and high-temperature metallurgy environments, has risen over the past decades in a continuous attempt to increase process control, improve energy and process efficiency in production, reduce operational and maintenance costs, increase safety, and perform condition-based maintenance in equipment and structures operating in high-temperature, harsh-environment conditions. The increased reliability, improved performance, and development of new sensors and networks with a multitude of components, especially wireless networks, are the target for operation in harsh environments. Gas sensors, in particular hydrogen gas sensors, operating above 200°C are required in the instrumentation, process control and general safety of a number of industries including coal, natural gas, and nuclear power generation facilities, the aerospace and automotive industries, metallurgical production and defense-related applications. The surface acoustic wave (SAW) platform is a particularly promising option for high-temperature, harsh-environment gas sensing applications since the platform exhibits advantages, such as battery-free and wireless operation, small size, possibility for scale production using well-developed technologies from the semiconductor industry, and low cost of installation and operation. In this work, one-port SAW resonators (SAWRs) operating along five different orientations on a commercially available langasite (LGS) wafer were designed, fabricated, and used as high-temperature H2 sensors. Two of the selected orientations were predicted and confirmed to have temperature-compensated operation above 150°C. A gas sensor test setup was developed, capable of gas cycling between N2, O2 and N2/H2 mixtures under extended high-temperature periods (up to 650°C for over 20 hours). Thin film Pt-Al2O3 was used as the electrode material for transducers and reflectors capable of high-temperature operation, and also as H2 sensing film. In addition, yttria-stabilized zirconia (YSZ) thin films with Pt decoration were tested as sensing films aimed to enhance the SAWR sensor response to H2. The SAW devices were monitored in excess of 1700 hours in real-time during gas cycling sequences up to 600°C, leading to the following findings: i) the Pt-Al2O3 electrodes performed better for H2 sensing than the Pt-decorated YSZ sensing film, showing as much as 50% higher frequency response variation in the 200°C to 400°C range; ii) different crystallographic orientations operating on the same LGS wafer experienced different responses to H2 exposures up to 500°C; iii) the surface oxidation state of the SAWR sensors was shown to have an important impact on subsequent H2 exposure responses. Additionally, the feasibility of a sensor system capable of detecting H2 and determining the ambient temperature simultaneously by employing two different SAWR sensors operating along different LGS orientations was examined. Finally, wireless interrogation of a SAWR sensor was successful within the gas cycling test fixture, and successful wireless H2 detection was achieved above 400°C

Mapping the interaction of B cell Leukemia 3 (BCL-3) and nuclear factor κB (NF-κB) p50 identifies a BCL-3-mimetic anti-inflammatory peptide

The NF-κB transcriptional response is tightly regulated by a number of processes including the phosphorylation, ubiquitination, and subsequent proteasomal degradation of NF-κB subunits. The IκB family protein BCL-3 stabilizes a NF-κB p50 homodimer·DNA complex through inhibition of p50 ubiquitination. This complex inhibits the binding of the transcriptionally active NF-κB subunits p65 and c-Rel on the promoters of NF-κB target genes and functions to suppress inflammatory gene expression. We have previously shown that the direct interaction between p50 and BCL-3 is required for BCL-3-mediated inhibition of pro-inflammatory gene expression. In this study we have used immobilized peptide array technology to define regions of BCl-3 that mediate interaction with p50 homodimers. Our data show that BCL-3 makes extensive contacts with p50 homodimers and in particular with ankyrin repeats (ANK) 1, 6, and 7, and the N-terminal region of Bcl-3. Using these data we have designed a BCL-3 mimetic peptide based on a region of the ANK1 of BCL-3 that interacts with p50 and shares low sequence similarity with other IκB proteins. When fused to a cargo carrying peptide sequence this BCL-3-derived peptide, but not a mutated peptide, inhibited Toll-like receptor-induced cytokine expression in vitro. The BCL-3 mimetic peptide was also effective in preventing inflammation in vivo in the carrageenan-induced paw edema mouse model. This study demonstrates that therapeutic strategies aimed at mimicking the functional activity of BCL-3 may be effective in the treatment of inflammatory disease

Tetramerization reinforces the dimer interface of MnSOD.

Two yeast manganese superoxide dismutases (MnSOD), one from Saccharomyces cerevisiae mitochondria (ScMnSOD) and the other from Candida albicans cytosol (CaMnSODc), have most biochemical and biophysical properties in common, yet ScMnSOD is a tetramer and CaMnSODc is a dimer or "loose tetramer" in solution. Although CaMnSODc was found to crystallize as a tetramer, there is no indication from the solution properties that the functionality of CaMnSODc in vivo depends upon the formation of the tetrameric structure. To elucidate further the functional significance of MnSOD quaternary structure, wild-type and mutant forms of ScMnSOD (K182R, A183P mutant) and CaMnSODc (K184R, L185P mutant) with the substitutions at dimer interfaces were analyzed with respect to their oligomeric states and resistance to pH, heat, and denaturant. Dimeric CaMnSODc was found to be significantly more subject to thermal or denaturant-induced unfolding than tetrameric ScMnSOD. The residue substitutions at dimer interfaces caused dimeric CaMnSODc but not tetrameric ScMnSOD to dissociate into monomers. We conclude that the tetrameric assembly strongly reinforces the dimer interface, which is critical for MnSOD activity

Estudio médico-tanatológico de la momia del Cerro Nevado del Chuscha

Fil: Mazziotti, Gerardo E.. Mendoza. Cuerpo Médico ForenseFil: Vargas, Armando P.. Mendoza. Cuerpo Médico Forens