Anti-vortex dynamics in magnetic nanostripes

In a thin magnetic nanostripe, an anti-vortex nucleates inside a moving domain wall when driven by an in-plane magnetic field greater than the so-called Walker field. The nucleated anti-vortex must cross the width of the nanostripe before the domain wall can propagate again, leading to low average domain wall speeds. A large out-of-plane magnetic field, applied perpendicularly to the plane of the nanostripe, inhibits the nucleation of the anti-vortex leading to fast domain wall speeds for all in-plane driving fields. We present micromagnetic simulation results relating the anti-vortex dynamics to the strength of the out-of-plane field. An asymmetry in the motion is observed which depends on the alignment of the anti-vortex core magnetic moments to the direction of the out-of-plane field. The size of the core is directly related to its crossing speed, both depending on the strength of the perpendicular field and the alignment of the core moments and direction of the out-of-plane field.Comment: 10 pages, 3 figure

Dark Matter Searches with HAWC

The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 0.5 TeV - 100 TeV gamma-rays and cosmic-rays in the State of Puebla, Mexico at an altitude of 4100m. The HAWC observatory performed an indirect search for dark matter via GeV-TeV photons resulting from dark matter annihilation and decay considering various sources, including dwarf spheroidal galaxies (dSphs), the M31 galaxy and the Virgo cluster, as well as a combined limit using the dSphs. HAWC has not seen statistically significant excess from these sources. We searched for dark matter annihilation and decay at dark matter masses above 1 TeV. We will present the annihilation cross-section and decay lifetime limits.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

The Restructuring and Privatisation of British Rail: Was it really that bad?

Following the government�s decision to place Railtrack into administration (October 2001), attention has focused on what went wrong with privatisation, and how crucial network investment will be financed in future. This paper uses a social cost-benefit analysis framework to assess whether the restructuring and privatisation of British Rail has produced savings in operating costs. The paper shows that major efficiencies have been achieved, consumers have benefited through lower prices, whilst the increased government subsidy has been largely recouped through privatisation proceeds. We find that output quality has also improved (pre-Hatfield). The achievement of further savings will be key to delivering improved rail services in the future. This paper finds that a privatised structure, where shareholders demand a return on their investment, has led to significant improvements in operating efficiency - it remains to be seen whether the new regime, with a not-for-profit infrastructure owner, will deliver the same efficiency improvements

Two-dimensional Moist Stratified Turbulence and the Emergence of Vertically Sheared Horizontal Flows

Moist stratified turbulence is studied in a two-dimensional Boussinesq system influenced by condensation and evaporation. The problem is set in a periodic domain and employs simple evaporation and condensation schemes, wherein both the processes push parcels towards saturation. Numerical simulations demonstrate the emergence of a moist turbulent state consisting of ordered structures with a clear power-law type spectral scaling from initially spatially uncorrelated conditions. An asymptotic analysis in the limit of rapid condensation and strong stratification shows that, for initial conditions with enough water substance to saturate the domain, the equations support a straightforward state of moist balance characterized by a hydrostatic, saturated, vertically sheared horizontal flow (VSHF). For such initial conditions, by means of long time numerical simulations, the emergence of moist balance is verified. Specifically, starting from uncorrelated data, subsequent to the development of a moist turbulent state, the system experiences a rather abrupt transition to a regime which is close to saturation and dominated by a strong VSHF. On the other hand, initial conditions which do not have enough water substance to saturate the domain, do not attain moist balance. Rather, the system remains in a turbulent state and oscillates about moist balance. Even though balance is not achieved with these general initial conditions, the time scale of oscillation about moist balance is much larger than the imposed time scale of condensation and evaporation, thus indicating a distinct dominant slow component in the moist stratified two-dimensional turbulent system.Comment: 23 pages. 9 figure

Synthesis of 4-Thiazolidinone Small Molecules as Potential Inhibitors of the Arp2/3 Complex

Life-essential cellular processes such as endocytosis, motility, and division rely on a cell’s ability to precisely regulate construction of actin filaments in response to external factors and signals. Intrinsically involved in this process is the Actin Related Protein 2/3 (Arp2/3) Complex, a seven-subunit ATPase that functions by nucleating a daughter branch of actin from the side of a pre-existing microfilament. Active Arp2/3 complex is necessary for the proliferation of certain metastatic cancers, and inhibition of Arp2/3 complex is emerging as a potentially useful treatment strategy for such cancers. We describe synthesis and in vitro assays of 4-thiazolidinones predicted by computational methods to inhibit of Arp2/3 Complex strongly, and therefore serve as potential lead compounds for drug development. Known Arp2/3 inhibitor CK-869 serves as the starting point for derivative synthesis. We discuss the efforts towards the synthesis of new compounds and the biochemical data collected about their potency

Antivortex Dynamics in Magnetic Nanostripes

In a thin magnetic nanostripe, an antivortex nucleates inside a moving domain wall when driven by an in-plane magnetic field greater than the so-called Walker field. The nucleated antivortex must cross the width of the nanostripe before the domain wall can propagate again, leading to low average domain wall speeds. A large out-of-plane magnetic field, applied perpendicularly to the plane of the nanostripe, inhibits the nucleation of the antivortex leading to fast domain wall speeds for all in-plane driving fields. We present micromagnetic simulation results relating the antivortex dynamics to the strength of the out-of-plane field. An asymmetry in the motion is observed which depends on the alignment of the antivortex core magnetic moments to the direction of the out-of-plane field. The size of the core is directly related to its crossing speed, both depending on the strength of the perpendicular field and the alignment of the core moments and direction of the out-of-plane field

Many new voters make the Granite State one to watch in November

A third of potential voters in New Hampshire during the fall of 2008 have become eligible to vote in the state. Further, these potential new voters are more likely to identify with the Democratic Party and less likely to identify as Republicans than are established New Hampshire voters, contributing to the state\u27s purple status

Invited commentary on Stewart and Davis " 'Big data' in mental health research-current status and emerging possibilities"

No abstract available