Resonance-continuum interference in the di-photon Higgs signal at the LHC

A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg -> H -> gamma gamma, with the continuum QCD background, gg -> gamma gamma induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg -> gamma gamma scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.Comment: 10 pages, 2 figure

Diffusion Process in a Flow

We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes. We establish circumstances under which the dispersion of passive contaminants in a forced, deterministic or random, flow can be consistently interpreted as a Markovian diffusion process. In case of conservative forcing the repulsive case only, $\vec{F}=\vec{\nabla }V$ with $V(\vec{x},t)$ bounded from below, is unquestionably admitted by the compatibility conditions. A class of diffusion processes is exemplified, such that the attractive forcing is allowed as well, due to an appropriate compensation coming from the "pressure" term. The compressible Euler flows form their subclass, when regarded as stochastic processes.Comment: 10 pages, Late

Numerical Schemes for Multivalued Backward Stochastic Differential Systems

We define some approximation schemes for different kinds of generalized backward stochastic differential systems, considered in the Markovian framework. We propose a mixed approximation scheme for a decoupled system of forward reflected SDE and backward stochastic variational inequality. We use an Euler scheme type, combined with Yosida approximation techniques.Comment: 13 page

Non-equilibrium phase transition in a sheared granular mixture

The dynamics of an impurity (or tracer particle) immersed in a dilute granular gas under uniform shear flow is investigated. A non-equilibrium phase transition is identified from an exact solution of the inelastic Boltzmann equation for a granular binary mixture in the tracer limit, where the impurity carries either a vanishing (disordered phase) or a finite (ordered phase) fraction of the total kinetic energy of the system. In the disordered phase, the granular temperature ratio (impurity "temperature" over that of the host fluid) is finite, while it diverges in the ordered phase. To correctly capture this extreme violation of energy equipartition, we show that the picture of an impurity enslaved to the host fluid is insufficient

Soil sampling bulk-density in the coastal lowlands of South-East Queensland

Bulk density is commonly measured in compaction, cultivation, land evaluation and site classification studies in forestry. Typically, measurements are made using a small-diameter core sampler (an integral open drive sampler) which is manually driven into the soil profile. The study reported in this paper was designed to determine the effects of sampler size on bulk density estimates, and to identify optimal sampling intensities for the coastal lowlands of south-east Queensland. Four sampler sizes were tested (internal diameters of 3.48, 4.83, 5.98 and 9.12 cm, and all approximately 10 cm in length). All sampler sizes provided consistent estimates of bulk density for a range of soil types and conditions. The accuracy of bulk density assessment was not improved by increasing sampler diameter beyond 5.98 cm. The results suggested that the core sampler technique can be used efficiently in a wider range of soil conditions than that recommended in the literature. Comparison of variances estimated for the four sampler sizes indicated no significant differences between either sampler size or site, and no significant 'site by sampler size' interaction. A single pooled estimate of variance was therefore used to recommend sampling intensities for coastal lowland soils. With any of the samplers used in this study, five replications will provide a point estimate of bulk density with a precision of ± 0.1 g cm -3; at the 95% probability level

Relationships between cone penetration resistance, bulk density, and moisture content in uncultivated, repacked, and cultivated hardsetting and non-hardsetting soils from the coastal lowlands of south-east Queensland

Relationships between cone penetration resistance (PR), soil moisture (SM), and bulk density (BD) were derived for: (i) cultivated (ripped) and uncultivated, hardsetting and non-hardsetting, field soils; and (ii) repacked cores of the uncultivated soils. Each of the soils supports commercial Pinus plantations in the coastal lowlands of south-east Queensland, Australia. Penetration resistance was positively correlated with bulk density and negatively correlated with soil moisture for all soils. In the uncultivated soils, penetration resistance was less sensitive to bulk density than typically reported in the literature, or than observed in the cultivated soils where a wider range of bulk density values was studied. In both the cultivated and the repacked soils, penetration resistance was more sensitive to soil moisture at higher bulk density, and more sensitive to bulk density at lower soil moisture. It was not possible to fit the same models to uncultivated, repacked, and cultivated soils, and therefore not possible to compare relationships for each statistically. Relationships between penetration resistance, bulk density, and soil moisture were best described by additive models in the uncultivated soils and multiplicative models in the cultivated soils. For the repacked soils, models had to be developed relating penetration resistance to bulk density for each soil moisture class separately. The study demonstrated that: (i) relationships between penetration resistance, bulk density, and soil moisture were insufficiently sensitive to predict responses in the penetration resistance of field soils tochanges in soil moisture, as might occur temporally, or bulk density, as might occur with compaction or reconsolidation after cultivation; and (ii) repacked soils could not be used to simulate the relationships between penetration resistance, bulk density, and soil moisture for cultivated field soils. Therefore, penetration resistances measured at different times in studies in which either bulk density or soil moisture are expected to change cannot be easily compared. In these situations, which include compaction and consolidation studies, both penetration resistance and bulk density, or bulk density alone, should be used to monitor change. Relationships between penetration resistance, soil moisture, and bulk density, together with moisture characteristic drying curves for individual soils, were used to define relationships between penetration resistance and matric suction. These relationships define a soil characteristic that may be useful for: (i) explaining varying responses of different soils to drying; (ii) explaining various Pinus seedling growth responses to cultivation and compaction; and (iii) delineating soils which are functionally hardsetting upon drying

Broken symmetries and directed collective energy transport

We study the appearance of directed energy current in homogeneous spatially extended systems coupled to a heat bath in the presence of an external ac field E(t). The systems are described by nonlinear field equations. By making use of a symmetry analysis we predict the right choice of E(t) and obtain directed energy transport for systems with a nonzero topological charge Q. We demonstrate that the symmetry properties of motion of topological solitons (kinks and antikinks) are equivalent to the ones for the energy current. Numerical simulations confirm the predictions of the symmetry analysis and, moreover, show that the directed energy current drastically increases as the dissipation parameter $\alpha$ reduces. Our results generalize recent rigorous theories of currents generated by broken time-space symmetries to the case of interacting many-particle systems.Comment: 4 pages, 2 figure

Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis

Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands

Driven diffusion in a periodically compartmentalized tube: homogeneity versus intermittency of particle motion

We study the effect of a driving force F on drift and diffusion of a point Brownian particle in a tube formed by identical ylindrical compartments, which create periodic entropy barriers for the particle motion along the tube axis. The particle transport exhibits striking features: the effective mobility monotonically decreases with increasing F, and the effective diffusivity diverges as F → ∞, which indicates that the entropic effects in diffusive transport are enhanced by the driving force. Our consideration is based on two different scenarios of the particle motion at small and large F, homogeneous and intermittent, respectively. The scenarios are deduced from the careful analysis of statistics of the particle transition times between neighboring openings. From this qualitative picture, the limiting small-F and large-F behaviors of the effective mobility and diffusivity are derived analytically. Brownian dynamics simulations are used to find these quantities at intermediate values of the driving force for various compartment lengths and opening radii. This work shows that the driving force may lead to qualitatively different anomalous transport features, depending on the geometry design