Simulation of transient energy distributions in sub-ns streamer formation

Breakdown and streamer formation is simulated in atmospheric pressure nitrogen for a 2D planar electrode system. A PIC code with multigrid potential solver is used to simulate the evolution of the non-equilibrium ionization front on sub-nanosecond timescales. The ion and electron energy distributions are computed, accounting for the inclusion of inelastic scattering of electrons, and collisionally excited metastable production and ionization. Of particular interest is the increased production of metastable and low-energy ions and electrons when the applied field is reversed during the progress of the ionization front, giving insight into the improved species yields in nanosecond pulsed systems

On multiplicities in length spectra of arithmetic hyperbolic three-orbifolds

Asymptotic laws for mean multiplicities of lengths of closed geodesics in arithmetic hyperbolic three-orbifolds are derived. The sharpest results are obtained for non-compact orbifolds associated with the Bianchi groups SL(2,o) and some congruence subgroups. Similar results hold for cocompact arithmetic quaternion groups, if a conjecture on the number of gaps in their length spectra is true. The results related to the groups above give asymptotic lower bounds for the mean multiplicities in length spectra of arbitrary arithmetic hyperbolic three-orbifolds. The investigation of these multiplicities is motivated by their sensitive effect on the eigenvalue spectrum of the Laplace-Beltrami operator on a hyperbolic orbifold, which may be interpreted as the Hamiltonian of a three-dimensional quantum system being strongly chaotic in the classical limit.Comment: 29 pages, uuencoded ps. Revised version, to appear in NONLINEARIT

Corrections to Gravity due to a Sol Manifold Extra Dimensional Space

The corrections to the gravitational potential due to a Sol extra dimensional compact manifold, denoted as $M_A^3$, are studied. The total spacetime is of the form $M^4\times M_A^3$. The range of the Sol corrections is investigated and compared to the range of the $T^3$ corrections.Comment: 13 pages, 10 figures, published versio

Seasonal variation and impact of waste-water lagoons as larval habitat on the population dynamics of Culicoides sonorensis (Diptera:Ceratpogonidae) at two dairy farms in northern California.

The Sacramento (northern Central) Valley of California (CA) has a hot Mediterranean climate and a diverse ecological landscape that is impacted extensively by human activities, which include the intensive farming of crops and livestock. Waste-water ponds, marshes, and irrigated fields associated with these agricultural activities provide abundant larval habitats for C. sonorensis midges, in addition to those sites that exist in the natural environment. Within this region, C. sonorensis is an important vector of bluetongue (BTV) and related viruses that adversely affect the international trade and movement of livestock, the economics of livestock production, and animal welfare. To characterize the seasonal dynamics of immature and adult C. sonorensis populations, abundance was monitored intensively on two dairy farms in the Sacramento Valley from August 2012- to July 2013. Adults were sampled every two weeks for 52 weeks by trapping (CDC style traps without light and baited with dry-ice) along N-S and E-W transects on each farm. One farm had large operational waste-water lagoons, whereas the lagoon on the other farm was drained and remained dry during the study. Spring emergence and seasonal abundance of adult C. sonorensis on both farms coincided with rising vernal temperature. Paradoxically, the abundance of midges on the farm without a functioning waste-water lagoon was increased as compared to abundance on the farm with a waste-water lagoon system, indicating that this infrastructure may not serve as the sole, or even the primary larval habitat. Adult midges disappeared from both farms from late November until May; however, low numbers of parous female midges were detected in traps set during daylight in the inter-seasonal winter period. This latter finding is especially critical as it provides a potential mechanism for the "overwintering" of BTV in temperate regions such as northern CA. Precise documentation of temporal changes in the annual abundance and dispersal of Culicoides midges is essential for the creation of models to predict BTV infection of livestock and to develop sound abatement strategies

Oral ibandronate for the treatment of metastatic bone disease in breast cancer: efficacy and safety results from a randomized, double-blind, placebo-controlled trial

Background: We report the first results of a randomized trial assessing a new oral aminobisphosphonate, ibandronate, in patients with bone metastases from breast cancer. Patients and methods: Patients (n = 435) received placebo, or oral ibandronate 20 mg or 50 mg once-daily for 96 weeks. The primary efficacy measure was the number of 12-week periods with new bone complications [skeletal morbidity period rate (SMPR)]. Multivariate Poisson regression analysis assessed the relative risk reduction of skeletal-related events. Secondary efficacy analyses included bone pain and analgesic use. Adverse events were monitored. Results: SMPR was significantly reduced with oral ibandronate [placebo 1.2, 20 mg group 0.97 (P = 0.024), 50 mg group 0.98 (P = 0.037)]. Ibandronate 50 mg significantly reduced the need for radiotherapy (P = 0.005 versus placebo). The relative risk of skeletal events was reduced by 38% (20 mg dose) and 39% (50 mg dose) versus placebo (P = 0.009 and P = 0.005). The tolerability profile of ibandronate was similar to placebo. Conclusions: Oral ibandronate is an effective and well-tolerated treatment for metastatic bone disease. The 50 mg dose is being further evaluated in clinical trials, and this dose was recently approved in the European Union for the prevention of skeletal events in patients with breast cancer and bone metastase

Fe-chitosan complexes for oxidative degradation of emerging contaminants in water: Structure, activity, and reaction mechanism

Versatile and ecofriendly methods to perform oxidations at near-neutral pH are of crucial importance for processes aimed at purifying water. Chitosan, a deacetylated form of chitin, is a promising starting material owing to its biocompatibility and ability to form stable films and complexes with metals. Here, we report a novel chitosan-based organometallic complex that was tested both as homogeneous and heterogeneous catalyst in the degradation of contaminants of emerging concern in water. The stoichiometry of the complex was experimentally verified with different metals, namely, Cu(II), Fe(III), Fe(II), Co(II), Pd(II), and Mn(II), and we identified the chitosan-Fe(III) complex as the most efficient catalyst. This complex effectively degraded phenol, triclosan, and 3-chlorophenol in the presence of hydrogen peroxide. A putative ferryl-mediated reaction mechanism is proposed based on experimental data, density functional theory calculations, and kinetic modeling. Finally, a film of the chitosan-Fe(III) complex was synthesized and proven a promising supported heterogeneous catalyst for water purification

Strange form factors of the nucleon in a two-component model

The strange form factors of the nucleon are studied in a two-component model consisting of a three-quark intrinsic structure surrounded by a meson cloud. A comparison with the available experimental world data from the SAMPLE, PVA4, HAPPEX and G0 collaborations shows a good overall agreement. The strange magnetic moment is found to be positive, 0.315 nm.Comment: 11 pages, 2 tables, 5 figures, accepted for publication in J. Phys. G. Revised version, new figures, extra table, new results, updated reference