Type IIB Solutions with Interpolating Supersymmetries

We study type IIB supergravity solutions with four supersymmetries that interpolate between two types widely considered in the literature: the dual of Becker and Becker's compactifications of M-theory to 3 dimensions and the dual of Strominger's torsion compactifications of heterotic theory to 4 dimensions. We find that for all intermediate solutions the internal manifold is not Calabi-Yau, but has SU(3) holonomy in a connection with a torsion given by the 3-form flux. All 3-form and 5-form fluxes, as well as the dilaton, depend on one function appearing in the supersymmetry spinor, which satisfies a nonlinear differential equation. We check that the fields corresponding to a flat bound state of D3/D5-branes lie in our class of solutions. The relations among supergravity fields that we derive should be useful in studying new gravity duals of gauge theories, as well as possibly compactifications.Comment: 27pp, v2 REVTeX4, typographical fixes and minor clarifications, v3 added ref, modified discussion of RR axion slightl

Exotic ρ±ρ0\rho^\pm\rho^0 state photoproduction

It is shown that the list of unusual mesons planned for a careful study in photoproduction can be extended by the exotic states $X^\pm(1600)$ with $I^G(J ^{PC})=2^+(2^{++})$ which should be looked for in the $\rho^\pm\rho^0$ decay channels in the reactions $\gamma N\to\rho^\pm\rho^0N$ and $\gamma N\to\rho^\pm \rho^0\Delta$. The full classification of the $\rho^\pm\rho^0$ states by their quantum numbers is presented. A simple model for the spin structure of the $\gamma p\to f_2(1270)p$, $\gamma p\to a^0_2(1320)p$, and $\gamma N\to X^\pm (N, \Delta)$ reaction amplitudes is formulated and the tentative estimates of the corresponding cross sections at the incident photon energy $E_\gamma\approx 6$ GeV are obtained: $\sigma(\gamma p\to f_2(1270)p)\approx0.12$ $\mu$b, $\sigma(\gamma p\to a^0_2(1320)p)\approx0.25$ $\mu$b, $\sigma(\gamma N\to X^\pm N\to\rho^\pm\rho^0N)\approx0.018$ $\mu$b, and $\sigma(\gamma p\to X^-\Delta^{++ }\to\rho^-\rho^0\Delta^{++})\approx0.031$ $\mu$b. The problem of the $X^\pm$ signal extraction from the natural background due to the other $\pi^\pm\pi^0 \pi^+\pi^-$ production channels is discussed. In particular the estimates are presented for the $\gamma p\to h_1(1170)\pi^+n$, $\gamma p\to\rho'^{+}n\to \pi^+\pi^0\pi^+\pi^-n$, and $\gamma p\to\omega\rho^0p$ reaction cross sections. Our main conclusion is that the search for the exotic $X^\pm(2^+(2^{++}))$ states is quite feasible at JEFLAB facility. The expected yield of the $\gamma N\to X^\pm N\to\rho^\pm\rho^0N$ events in a 30-day run at the 100% detection efficiency approximates $2.8\times10^6$ events.Comment: 19 pages, revtex, 1 figure in postscipt, some comments and references added, a few minor typos corrected, to be published in Phys. Rev.

Applications of electrified dust and dust devil electrodynamics to Martian atmospheric electricity

Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kVm-1 to 100 kVm-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ measurements

A case-only study to identify genetic modifiers of breast cancer risk for BRCA1/BRCA2 mutation carriers

Breast cancer (BC) risk for BRCA1 and BRCA2 mutation carriers varies by genetic and familial factors. About 50 common variants have been shown to modify BC risk for mutation carriers. All but three, were identified in general population studies. Other mutation carrier-specific susceptibility variants may exist but studies of mutation carriers have so far been underpowered. We conduct a novel case-only genome-wide association study comparing genotype frequencies between 60,212 general population BC cases and 13,007 cases with BRCA1 or BRCA2 mutations. We identify robust novel associations for 2 variants with BC for BRCA1 and 3 for BRCA2 mutation carriers, P < 10−8, at 5 loci, which are not associated with risk in the general population. They include rs60882887 at 11p11.2 where MADD, SP11 and EIF1, genes previously implicated in BC biology, are predicted as potential targets. These findings will contribute towards customising BC polygenic risk scores for BRCA1 and BRCA2 mutation carriers

Fractionation of solar wind minor ion precipitation by the lunar paleomagnetosphere

The analysis of solar wind material implanted within lunar soil has provided significant insight into the makeup and evolutionary history of the solar wind and, by extension, the Sun and protosolar nebula. These analyses often rely on the tacit assumption that the Moon has served as an unbiased recorder of solar wind composition over its 4.5 billion yr lifetime. Recent work, however, has shown that for a majority of its lifetime, the Moon has possessed a dynamo that generates a global magnetic field with surface field strengths of at least 5 μT. In turn, the presence of such a field has been shown to significantly alter the lunar–solar wind interaction via the formation of a lunar “paleomagnetosphere.” This paleomagnetosphere has implications for the flux of solar wind minor ions to the lunar surface and their subsequent implantation in lunar soil grains. Here we use a three-dimensional hybrid plasma model to investigate the effects of the lunar paleomagnetosphere on the dynamics and precipitation of solar wind minor ions to the lunar surface. The model results show that the lunar paleomagnetosphere can suppress minor ion fluxes to the lunar surface by more than an order of magnitude and strongly fractionates the precipitating solar wind in a complex, nonlinear fashion with respect to both the minor ion charge-to-mass ratio and the surface paleomagnetic field strength. We discuss the implications of these results with respect to both the analysis of trapped material in lunar grains and the semiquantitative 40Ar/36Ar antiquity indicator for lunar soils

Ion Dynamics at the Magnetopause of Ganymede

We study the dynamics of the thermal O+ and H+ ions at Ganymede's magnetopause when Ganymede is inside and outside of the Jovian plasma sheet using a three-dimensional hybrid model of plasma (kinetic ions, fluid electrons). We present the global structure of the electric fields and power density (E ⋅ J) in the magnetosphere of Ganymede and show that the power density at the magnetopause is mainly positive and on average is +0.95 and +0.75 nW/m3 when Ganymede is inside and outside the Jovian plasma sheet, respectively, but locally it reaches over +20 nW/m3. Our kinetic simulations show that ion velocity distributions at the vicinity of the upstream magnetopause of Ganymede are highly non-Maxwellian. We investigate the energization of the ions interacting with the magnetopause and find that the energy of those particles on average increases by a factor of 8 and 30 for the O+ and H+ ions, respectively. The energy of these ions is mostly within 1–100 keV for both species after interaction with the magnetopause, but a few percentages reach to 0.1–1 MeV. Our kinetic simulations show that a small fraction ((Formula presented.) 25%) of the corotating Jovian plasma reach the magnetopause, but among those &gt;50% cross the high-power density regions at the magnetopause and gain energy. Finally, we compare our simulation results with Galileo observations of Ganymede's magnetopause crossings (i.e., G8 and G28 flybys). There is an excellent agreement between our simulations and observations, particularly our simulations fully capture the size and structure of the magnetosphere

Particle-In-Cell Modeling of Martian Magnetic Cusps and Their Role in Enhancing Nightside Ionospheric Ion Escape

Amongst various escape channels, ion outflow is a major contributor to atmospheric loss at Mars over geologic time. On Mars' nightside, observations have indicated that cusp regions within crustal magnetic fields are associated with phenomena such as accelerated particle populations, discrete auroral emissions, and ionospheric outflow; however, the kinetic physics occurring within crustal magnetic cusps is poorly understood. Here, we present 1.5-dimensional particle-in-cell simulations of magnetospheric-ionospheric interactions within martian crustal magnetic cusp regions of varying strength. Simulation results demonstrate the formation of quasi-static, field-aligned potentials pointing away from Mars that accelerate electrons into the martian atmosphere while accelerating ions away, thereby enhancing ionospheric escape. Escaping ionospheric flux scales with crustal field strength, with 160 nT crustal fields yielding >2× the ion escape flux than in the case with no crustal fields. We discuss these results andconclude that magnetic cusp regions may be significant sources of ion loss at Mars.Peer reviewe

Simulating the Reiner Gamma Swirl: The Long‐term Effect of Solar Wind Standoff

International audienceThe Reiner Gamma swirl is a prime location to investigate the lunar albedo patterns and their co‐location with magnetic anomalies. The precise relationship between impinging plasma and the swirl, and in particular, how these interactions vary over the course of a lunar day, remains an open issue. Here we use a fully kinetic particle‐in‐cell code, coupled with a magnetic field model based on orbital‐altitude observations, and simulate the interaction with the Reiner Gamma anomaly for all plasma regimes the region is exposed to along a typical orbit, including different solar wind incidence angles and the Moon's crossing through the terrestrial magnetosphere. Consistent with the hypothesis that swirls form as a result of plasma interactions with near‐surface magnetic fields, we show that the energy flux profile produces a pattern similar to Reiner Gamma's alternating bright and darkly colored bands, but only when integrating over the full lunar orbit. We additionally show that including He2+ as a self‐consistent plasma species improves the match

Augmenting and assisting model elicitation tasks with 3D virtual world context metadata

Accurate process model elicitation continues to be a time consuming task, requiring skill on the part of the interviewer to extract explicit and tacit process information from the interviewee. Many errors occur in this elicitation stage that would be avoided by better activity recall, more consistent specification methods and greater engagement in the elicitation process by interviewees. Theories of situated cognition indicate that interactive 3D representations of real work environments engage and prime the cognitive state of the viewer. In this paper, our major contribution is to augment a previous process elicitation methodology with virtual world context metadata, drawn from a 3D simulation of the workplace. We present a conceptual and formal approach for representing this contextual metadata, integrated into a process similarity measure that provides hints for the business analyst to use in later modelling steps. Finally, we conclude with examples from two use cases to illustrate the potential abilities of this approach