Van der Waals interactions in the ground state of Mg(BH4)2 from density functional theory

In order to resolve an outstanding discrepancy between experiment and theory regarding the ground-state structure of Mg(BH4)2, we examine the importance of long-range dispersive interactions on the compound's thermodynamic stability. Careful treatment of the correlation effects within a recently developed nonlocal van der Waals density functional (vdW-DF) leads to a good agreement with experiment, favoring the {\alpha}-Mg(BH4)2 phase (P6122) and a closely related Mn(BH4)2-prototype phase (P3112) over a large set of polymorphs at low temperatures. Our study demonstrates the need to go beyond (semi)local density functional approximations for a reliable description of crystalline high-valent metal borohydrides.Comment: Phys. Rev. B, accepted, 7 pages, 4 figure

Effect of nonlocal interactions on the disorder-induced zero-bias anomaly in the Anderson-Hubbard model

To expand the framework available for interpreting experiments on disordered strongly correlated systems, and in particular to explore further the strong-coupling zero-bias anomaly found in the Anderson-Hubbard model, we ask how this anomaly responds to the addition of nonlocal electron-electron interactions. We use exact diagonalization to calculate the single-particle density of states of the extended Anderson-Hubbard model. We find that for weak nonlocal interactions the form of the zero-bias anomaly is qualitatively unchanged. The energy scale of the anomaly continues to be set by an effective hopping amplitude renormalized by the nonlocal interaction. At larger values of the nonlocal interaction strength, however, hopping ceases to be a relevant energy scale and higher energy features associated with charge correlations dominate the density of states.Comment: 9 pages, 7 figure

Synesthesia for manual alphabet letters and numeral signs in second-language users of signed languages

Many synesthetes experience colors when viewing letters or digits. We document, for the first time, an analogous phenomenon among users of signed languages who showed color synesthesia for fingerspelled letters and signed numerals. Four synesthetes experienced colors when they viewed manual letters and numerals (in two cases, colors were subjectively projected on to the hands). There was a correspondence between the colors experienced for written graphemes and their manual counterparts, suggesting that the development of these two types of synesthesia is interdependent despite the fact that these systems are superficially distinct and rely on different perceptual recognition mechanisms in the brain

A Spectral Method for Elliptic Equations: The Neumann Problem

Let $\Omega$ be an open, simply connected, and bounded region in $\mathbb{R}^{d}$, $d\geq2$, and assume its boundary $\partial\Omega$ is smooth. Consider solving an elliptic partial differential equation $-\Delta u+\gamma u=f$ over $\Omega$ with a Neumann boundary condition. The problem is converted to an equivalent elliptic problem over the unit ball $B$, and then a spectral Galerkin method is used to create a convergent sequence of multivariate polynomials $u_{n}$ of degree $\leq n$ that is convergent to $u$. The transformation from $\Omega$ to $B$ requires a special analytical calculation for its implementation. With sufficiently smooth problem parameters, the method is shown to be rapidly convergent. For $u\in C^{\infty}(\overline{\Omega})$ and assuming $\partial\Omega$ is a $C^{\infty}$ boundary, the convergence of $\Vert u-u_{n}\Vert_{H^{1}}$ to zero is faster than any power of $1/n$. Numerical examples in $\mathbb{R}^{2}$ and $\mathbb{R}^{3}$ show experimentally an exponential rate of convergence.Comment: 23 pages, 11 figure

Comparison of in situ and columnar aerosol spectral measurements during TexAQS-GoMACCS 2006: testing parameterizations for estimating aerosol fine mode properties

During the 2006 Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS-GoMACCS 2006), the optical, chemical and microphysical properties of atmospheric aerosols were measured on multiple mobile platforms and at ground based stations. In situ measurements of the aerosol light extinction coefficient (σ<sub>ep</sub>) were performed by two multi-wavelength cavity ring-down (CRD) instruments, one located on board the NOAA R/V <i>Ronald H. Brown</i> (RHB) and the other located at the University of Houston, Moody Tower (UHMT). An AERONET sunphotometer was also located at the UHMT to measure the columnar aerosol optical depth (AOD). The σ<sub>ep</sub> data were used to extract the extinction Ångström exponent (å<sub>ep</sub>), a measure of the wavelength dependence of σ<sub>ep</sub>. There was general agreement between the å<sub>ep</sub> (and to a lesser degree σ<sub>ep</sub>) measurements by the two spatially separated CRD instruments during multi-day periods, suggesting a regional scale consistency of the sampled aerosols. Two spectral models are applied to the σ<sub>ep</sub> and AOD data to extract the fine mode fraction of extinction (η) and the fine mode effective radius (<i>R</i><sub>eff,f</sub>). These two parameters are robust measures of the fine mode contribution to total extinction and the fine mode size distribution, respectively. The results of the analysis are compared to <i>R</i><sub>eff,f</sub> values extracted using AERONET V2 retrievals and calculated from in situ particle size measurements on the RHB and at UHMT. During a time period when fine mode aerosols dominated the extinction over a large area extending from Houston/Galveston Bay and out into the Gulf of Mexico, the various methods for obtaining <i>R</i><sub>eff,f</sub> agree qualitatively (showing the same temporal trend) and quantitatively (pooled standard deviation = 28 nm)

Multinet : enabler for next generation enterprise wireless services

Wireless communications are currently experiencing a fast migration toward the beyond third-generation (B3G)/fourth generation (4G) era. This represents a generational change in wireless systems: new capabilities related to mobility and new services support is required and new concepts as individual-centric, user-centric or ambient-aware communications are included. One of the main restrictions associated to wireless technology is mobility management, this feature was not considered in the design phase; for this reason, a complete solution is not already found, although different solutions are proposed and are being proposed. In MULTINET project, features as mobility and multihoming are applied to wireless network to provide the necessary network and application functionality enhancements for seamless data communication mobility considering end-user scenario and preferences. The aim of this paper is to show the benefits of these functionalities from the Service Providers and final User point of view

Even Between-Lap Pacing Despite High Within-Lap Variation During Mountain Biking

Purpose: Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain. Methods: A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean ± SD age = 27.2 ± 5.0 y, stature = 176.8 ± 8.1 cm, mass = 76.3 ± 11.7 kg, VO2max = 55.1 ± 6.0 mL · kg–1 . min–1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation. Results: There was no significant difference in lap times (P = .99) or lap velocity (P = .65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain. Conclusion: Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise

Scientific rationale of a Saturn probe mission

We describe the main scientific goals to be addressed by future in situ exploration of Saturn

The within-participant Correlation between s-RPE and Heart Rate in Youth Sport

The monitoring of training load is important to ensure athletes are adapting optimally to a training stimulus. Before quanti ca- tion of training load can take place, coaches must be con dent that the tools available are accurate. We aimed to quantify the within-participant correlation between the session rating of perceived exertion (s-RPE) and summated heart rate zone (sHRz) methods of monitoring internal training load. Training load (s-RPE and heart rate) data were collected for rugby, soc- cer and eld hockey eld-based training sessions over a 14- week in-season period. A total of 397 sessions were monitored (rugby n = 170, soccer n = 114 and eld hockey n = 113). With- in-subject correlations between s-RPE and sHRz were quanti- ed for each sport using a general linear model. Large correla- tions between s-RPE and the sHRz method were found for rugby (r = 0.68; 95 % CI 0.59–0.75) and eld hockey (r = 0.60; 95 % CI 0.47–0.71) with a very large correlation found for soccer (r = 0.72; 95 % CI 0.62–0.80). No signi cant di erences were found between the correlations for each sport. The very large and large correlations found between s-RPE and the sHRz meth- ods support the use of s-RPE in quantifying internal training load in youth sport