Statistics of Lyapunov exponent in one-dimensional layered systems

Localization of acoustic waves in a one dimensional water duct containing many randomly distributed air filled blocks is studied. Both the Lyapunov exponent and its variance are computed. Their statistical properties are also explored extensively. The results reveal that in this system the single parameter scaling is generally inadequate no matter whether the frequency we consider is located in a pass band or in a band gap. This contradicts the earlier observations in an optical case. We compare the results with two optical cases and give a possible explanation of the origin of the different behaviors.Comment: 6 pages revtex file, 6 eps figure

Magneto Transport of high TCR (temperature coefficient of resistance) La2/3Ca1/3MnO3: Ag Polycrystalline Composites

We report the synthesis, (micro)structural, magneto-transport and magnetization of polycrystalline La2/3Ca1/3MnO3:Agx composites with x = 0.0, 0.1, 0.2, 0.3 and 0.4. The temperature coefficient of resistance (TCR) near ferromagnetic (FM) transition is increased significantly with addition of Ag. The FM transition temperature (TFM) is also increased slightly with Ag addition. Magneto-transport measurements revealed that magneto-resistance MR is found to be maximum near TFM. Further the increased MR of up to 60% is seen above 300 K for higher silver added samples in an applied field of 7 Tesla. Sharp TCR is seen near TFM with highest value of up to 15 % for Ag (0.4) sample, which is an order of magnitude higher than as for present pristine sample and best value yet reported for any polycrystalline LCMO compound. Increased TCR, TFM and significant above room temperature MR of La2/3Ca1/3MnO3:Agx composites is explained on the basis of improved grains size and connectivity with silver addition in the matrix. Better coupled FM domains and nearly conducting grain boundaries give rise to improved physical properties of the La2/3Ca1/3MnO3 manganites.Comment: 16 pages Text + Figs. ACCEPTED: Solid State Communications (Sept. 2006

Traveling planetary-scale waves cause cloud variability on tidally locked aquaplanets

This is the author accepted manuscript.Data availability: A 200-day sample of model output data from each simulation presented in this study is available for public download at https://doi.org/10.5281/zenodo.7752337. The source code to generate the figures in this study is available at https://github.com/maureenjcohen/cloudcodeCloud cover at the planetary limb of water-rich Earth-like planets is likely to weaken chemical signatures in transmission spectra, impeding attempts to characterize these atmospheres. However, based on observations of Earth and solar system worlds, exoplanets with atmospheres should have both short-term weather and long-term climate variability, implying that cloud cover may be less during some observing periods. We identify and describe a mechanism driving periodic clear sky events at the terminators in simulations of tidally locked Earth-like planets. A feedback between dayside cloud radiative effects, incoming stellar radiation and heating, and the dynamical state of the atmosphere, especially the zonal wavenumber-1 Rossby wave identified in past work on tidally locked planets, leads to oscillations in Rossby wave phase speeds and in the position of Rossby gyres and results in advection of clouds to or away from the planet’s eastern terminator. We study this oscillation in simulations of Proxima Centauri b, TRAPPIST 1-e, and rapidly rotating versions of these worlds located at the inner edge of their stars’ habitable zones. We simulate time series of the transit depths of the 1.4 µm water feature and 2.7 µm carbon dioxide feature. The impact of atmospheric variability on the transmission spectra is sensitive to the structure of the dayside cloud cover and the location of the Rossby gyres, but none of our simulations have variability significant enough to be detectable with current methods.Edinburgh Earth, Ecology, and Environmental Doctoral Training PartnershipNatural Environment Research Council (NERC)UKRIScience and Technology Facilities Council (STFC)Leverhulme Trus

Inflation at the Electroweak Scale

We present a simple model for slow-rollover inflation where the vacuum energy that drives inflation is of the order of $G_F^{-2}$; unlike most models, the conversion of vacuum energy to radiation (``reheating'') is moderately efficient. The scalar field responsible for inflation is a standard-model singlet, develops a vacuum expectation value of the order of 4\times 10^6\GeV, has a mass of order 1\GeV, and can play a role in electroweak phenomena.Comment: 14 page

Two patients with a complete proximal rupture of the hamstring

Two men visited our Emergency Room because of a water-ski-accident. At physical examination, there was hematoma at the upper leg with loss of strength at extension of the hip and flexion of the knee. Both patients had a palpable gap just distal of the ischial tuberosity. Further imaging by sonography and MR-scan showed a rupture of the proximal hamstring tendon. Treatment was operative refixation of the hamstring tendons at the ischial tuberosity. Aftertreatment consisted of brace for 4 weeks after operation. Both patients returned to their pre-operatively sports, though at a lower level. Surgical treatment of a complete proximal rupture of the hamstrings is recommended in case of sportive patients

Gate-Controlled Ionization and Screening of Cobalt Adatoms on a Graphene Surface

We describe scanning tunneling spectroscopy (STS) measurements performed on individual cobalt (Co) atoms deposited onto backgated graphene devices. We find that Co adatoms on graphene can be ionized by either the application of a global backgate voltage or by the application of a local electric field from a scanning tunneling microscope (STM) tip. Large screening clouds are observed to form around Co adatoms ionized in this way, and we observe that some intrinsic graphene defects display a similar behavior. Our results provide new insight into charged impurity scattering in graphene, as well as the possibility of using graphene devices as chemical sensors.Comment: 19 pages, 4 figure

Effects of glucocorticoids on weight change during the treatment of Wegener's granulomatosis

Objective Weight gain is a side effect of glucocorticoid (GC) use, but the natural history and health implications of changes in weight that occur during the treatment of inflammatory disease are not understood. Methods We evaluated data from the Wegener's Granulomatosis Etanercept Trial. Patients were categorized according to clinical outcome at 1 year: remission (no disease flares), single flare, or multiple flares. Risk factors for gaining ≥10 kg were examined in multivariate models. Results Weights at baseline and 1 year were available for 157 (93%) of the 168 patients analyzed. During year 1, the mean cumulative prednisone dosage in the multiple flares subgroup was 7.9 gm, compared with 6.0 gm and 3.9 gm in the single flare and remission subgroups, respectively ( P 10 kg in the first year of treatment. The quantity of weight gained by patients during treatment has potential future health implications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58632/1/23561_ftp.pd

Self-Organization Leads to Supraoptimal Performance in Public Transportation Systems

The performance of public transportation systems affects a large part of the population. Current theory assumes that passengers are served optimally when vehicles arrive at stations with regular intervals. In this paper, it is shown that self-organization can improve the performance of public transportation systems beyond the theoretical optimum by responding adaptively to local conditions. This is possible because of a “slower-is-faster” effect, where passengers wait more time at stations but total travel times are reduced. The proposed self-organizing method uses “antipheromones” to regulate headways, which are inspired by the stigmergy (communication via environment) of some ant colonies

Autism as a disorder of neural information processing: directions for research and targets for therapy

The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself