Species and Chlorine Fertilisation Affect Dietary Cation-Anion Difference of Cool-Season Grasses

The Dietary Cation-Anion Difference [DCAD = (Na + K) - (Cl + S); Ender et al., 1971] is used in balancing rations for dry dairy cows. Low DCAD diets induce a mild, compensated metabolic acidosis that stimulates bone resorption, improves Ca homeostasis, and prevents milk fever. Dry cow rations contain a high proportion of forage and, therefore, forages fed two to four weeks prepartum should have a low or negative DCAD value. Our objectives were to evaluate the DCAD of five cool-season grass species grown in eastern Canada and to determine the effect of Cl fertilisation on the DCAD value of timothy (Phleum pratense L.)

Cavity QED with Diamond Nanocrystals and Silica Microspheres

Normal mode splitting is observed in a cavity QED system, in which nitrogen vacancy centers in diamond nanocrystals are coupled to whispering gallery modes in a silica microsphere. The composite nanocrystal-microsphere system takes advantage of the exceptional spin properties of nitrogen vacancy centers as well as the ultra high quality factor of silica microspheres. The observation of the normal mode splitting indicates that the dipole optical interaction between the relevant nitrogen vacancy center and whispering gallery mode has reached the strong coupling regime of cavity QED

Scalar conservation laws with nonconstant coefficients with application to particle size segregation in granular flow

Granular materials will segregate by particle size when subjected to shear, as occurs, for example, in avalanches. The evolution of a bidisperse mixture of particles can be modeled by a nonlinear first order partial differential equation, provided the shear (or velocity) is a known function of position. While avalanche-driven shear is approximately uniform in depth, boundary-driven shear typically creates a shear band with a nonlinear velocity profile. In this paper, we measure a velocity profile from experimental data and solve initial value problems that mimic the segregation observed in the experiment, thereby verifying the value of the continuum model. To simplify the analysis, we consider only one-dimensional configurations, in which a layer of small particles is placed above a layer of large particles within an annular shear cell and is sheared for arbitrarily long times. We fit the measured velocity profile to both an exponential function of depth and a piecewise linear function which separates the shear band from the rest of the material. Each solution of the initial value problem is non-standard, involving curved characteristics in the exponential case, and a material interface with a jump in characteristic speed in the piecewise linear case

Vismodegib resistant mutations are not selected in multifocal relapses of locally advanced basal cell carcinoma after vismodegib discontinuation.

Hedgehog pathway inhibitors (HPI) inactivating SMO 1, have become first line treatment for patients with locally advanced BCC (laBCC). HPI safety and efficacy have been shown in clinical trials2,3. Nevertheless, common adverse events lead to treatment discontinuation

Drag on a satellite moving across a spherical galaxy. I. Tidal and frictional forces in shortlived encounters

We derive a formalism, within the theory of linear response, for the analysis of the interaction of a satellite (the perturber) with a spherical galaxy whose equilibrium is described by a one-particle distribution function. We compute the formal expression of the force on the satellite including the self-gravity of the stars and the shift of the stellar center of mass. We apply the perturbative technique to the case of a satellite moving at high speed across a stellar system and find a natural decomposition of the force into a global component resulting from the tidal interaction and a component that is related to dynamical friction. When the satellite orbits outside the galaxy, we derive the force in the impulse approximation. In penetrating shortlived encounters, the wake excited in the density field is responsible for most of the deceleration. We find that dynamical friction rises from a memory effect involving only those stars perturbed along the path. The force can be written in terms of an effective Coulomb logarithm which now depends on the dynamical history. It is derived for two simple equilibrium density distributions. In the case of a homogeneous cloud, we compute the total energy loss: Tides excited by the satellite in the galaxy reduce the value of the energy loss by friction.Comment: 22 pages, Tex + 5 .ps figures Submitted to The Astrophysical Journa

Metastability in Josephson transmission lines

Thermal activation and macroscopic quantum tunneling in current-biased discrete Josephson transmission lines are studied theoretically. The degrees of freedom under consideration are the phases across the junctions which are coupled to each other via the inductances of the system. The resistively shunted junctions that we investigate constitute a system of N interacting degrees of freedom with an overdamped dynamics. We calculate the decay rate within exponential accuracy as a function of temperature and current. Slightly below the critical current, the decay from the metastable state occurs via a unique ("rigid") saddlepoint solution of the Euclidean action describing the simultaneous decay of the phases in all the junctions. When the current is reduced, a crossover to a regime takes place, where the decay occurs via an "elastic" saddlepoint solution and the phases across the junctions leave the metastable state one after another. This leads to an increased decay rate compared with the rigid case both in the thermal and the quantum regime. The rigid-to-elastic crossover can be sharp or smooth analogous to first- or second- order phase transitions, respectively. The various regimes are summarized in a current-temperature decay diagram.Comment: 11 pages, RevTeX, 3 PS-figures, revised versio

Crossovers in the thermal decay of metastable states in discrete systems

The thermal decay of linear chains from a metastable state is investigated. A crossover from rigid to elastic decay occurs when the number of particles, the single particle energy barrier or the coupling strength between the particles is varied. In the rigid regime, the single particle energy barrier is small compared to the coupling strength and the decay occurs via a uniform saddlepoint solution, with all degrees of freedom decaying instantly. Increasing the barrier one enters the elastic regime, where the decay is due to bent saddlepoint configurations using the elasticity of the chain to lower their activation energy. Close to the rigid-to-elastic crossover, nucleation occurs at the boundaries of the system. However, in large systems, a second crossover from boundary to bulk nucleation can be found within the elastic regime, when the single particle energy barrier is further increased. We compute the decay rate in the rigid and in the elastic regimes within the Gaussian approximation. Around the rigid-to-elastic crossover, the calculations are performed beyond the steepest descent approximation. In this region, the prefactor exhibits a scaling property. The theoretical results are discussed in the context of discrete Josephson transmission lines and pancake vortex stacks that are pinned by columnar defects.Comment: 13 pages, RevTeX, 7 PS-figure

Construction and commissioning of a technological prototype of a high-granularity semi-digital hadronic calorimeter

A large prototype of 1.3m3 was designed and built as a demonstrator of the semi-digital hadronic calorimeter (SDHCAL) concept proposed for the future ILC experiments. The prototype is a sampling hadronic calorimeter of 48 units. Each unit is built of an active layer made of 1m2 Glass Resistive Plate Chamber(GRPC) detector placed inside a cassette whose walls are made of stainless steel. The cassette contains also the electronics used to read out the GRPC detector. The lateral granularity of the active layer is provided by the electronics pick-up pads of 1cm2 each. The cassettes are inserted into a self-supporting mechanical structure built also of stainless steel plates which, with the cassettes walls, play the role of the absorber. The prototype was designed to be very compact and important efforts were made to minimize the number of services cables to optimize the efficiency of the Particle Flow Algorithm techniques to be used in the future ILC experiments. The different components of the SDHCAL prototype were studied individually and strict criteria were applied for the final selection of these components. Basic calibration procedures were performed after the prototype assembling. The prototype is the first of a series of new-generation detectors equipped with a power-pulsing mode intended to reduce the power consumption of this highly granular detector. A dedicated acquisition system was developed to deal with the output of more than 440000 electronics channels in both trigger and triggerless modes. After its completion in 2011, the prototype was commissioned using cosmic rays and particles beams at CERN.Comment: 49 pages, 41 figure

Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS

A scintillating fibre tracker is proposed to measure elastic proton scattering at very small angles in the ATLAS experiment at CERN. The tracker will be located in so-called Roman Pot units at a distance of 240 m on each side of the ATLAS interaction point. An initial validation of the design choices was achieved in a beam test at DESY in a relatively low energy electron beam and using slow off-the-shelf electronics. Here we report on the results from a second beam test experiment carried out at CERN, where new detector prototypes were tested in a high energy hadron beam, using the first version of the custom designed front-end electronics. The results show an adequate tracking performance under conditions which are similar to the situation at the LHC. In addition, the alignment method using so-called overlap detectors was studied and shown to have the expected precision.Comment: 12 pages, 8 figures. Submitted to Journal of Instrumentation (JINST

Performance of Glass Resistive Plate Chambers for a high granularity semi-digital calorimeter

A new design of highly granular hadronic calorimeter using Glass Resistive Plate Chambers (GRPCs) with embedded electronics has been proposed for the future International Linear Collider (ILC) experiments. It features a 2-bit threshold semi-digital read-out. Several GRPC prototypes with their electronics have been successfully built and tested in pion beams. The design of these detectors is presented along with the test results on efficiency, pad multiplicity, stability and reproducibility.Comment: 16 pages, 15 figure