The Jury System in Contemporary Ireland: In the Shadow of a Troubled Past

Jackson et al discuss the distinctive features of criminal trial by jury in Ireland, both north and south, to explain how the jury continues to survive within modern Ireland and how it also has managed to decline in significance

Parallel hierarchical global illumination

Solving the global illumination problem is equivalent to determining the intensity of every wavelength of light in all directions at every point in a given scene. The complexity of the problem has led researchers to use approximation methods for solving the problem on serial computers. Rather than using an approximation method, such as backward ray tracing or radiosity, we have chosen to solve the Rendering Equation by direct simulation of light transport from the light sources. This paper presents an algorithm that solves the Rendering Equation to any desired accuracy, and can be run in parallel on distributed memory or shared memory computer systems with excellent scaling properties. It appears superior in both speed and physical correctness to recent published methods involving bidirectional ray tracing or hybrid treatments of diffuse and specular surfaces. Like progressive radiosity methods, it dynamically refines the geometry decomposition where required, but does so without the excessive storage requirements for ray histories. The algorithm, called Photon, produces a scene which converges to the global illumination solution. This amounts to a huge task for a 1997-vintage serial computer, but using the power of a parallel supercomputer significantly reduces the time required to generate a solution. Currently, Photon can be run on most parallel environments from a shared memory multiprocessor to a parallel supercomputer, as well as on clusters of heterogeneous workstations

Efficacy of Flapping-wing Flight Via Dual Piezoelectric Actuation

A novel piezoelectric-actuated wing system featuring dual actuators for increased wing control is presented and evaluated for its forward-flight characteristics via theoretical modeling and physical wind tunnel testing. Flapping wing aerial systems serve as a middle ground between the traditional fixed-wing and rotary systems. Flapping wing aerial systems exhibit high maneuverability and stability at low speeds (like rotary systems) while maintaining increased efficiency (like fixed-wing systems). Flapping wings also eliminate the necessity of dangerous fast-moving propellers and open the door to actuation mechanisms other than traditional motors. This research explores one of these alternatives: the piezoelectric bending actuator. Piezoelectric materials produce a mechanical strain when an electric charge is applied. With an applied sinusoidal voltage, cantilevered bending piezoelectric actuators create oscillatory motion at the free end that can be translated into wing movement much more directly than a rotational motor. This direct actuation eliminates the need for gears and provides a mechanism for reducing the system\u27s weight. Furthermore, the simplified mechanism can improve robustness by removing contact surfaces that can become clogged or worn (e.g., using gears). While piezoelectric flapping-wing flight has many potential benefits, the combination has only been explored in insect-inspired hovering flight. This work explores the feasibility of larger, forward-flight systems to identify a framework for piezoelectrically-driven flapping-wing vehicles with wing-bending control. Theoretical and experimental analysis methods are presented to study piezoelectric flapping wing motion characteristics for lift and drag effects in flapping-wing aerial systems

Forming Disk Galaxies in Lambda CDM Simulations

We used fully cosmological, high resolution N-body + SPH simulations to follow the formation of disk galaxies with rotational velocities between 135 and 270 km/sec in a Lambda CDM universe. The simulations include gas cooling, star formation, the effects of a uniform UV background and a physically motivated description of feedback from supernovae. The host dark matter halos have a spin and last major merger redshift typical of galaxy sized halos as measured in recent large scale N--Body simulations. The simulated galaxies form rotationally supported disks with realistic exponential scale lengths and fall on both the I-band and baryonic Tully Fisher relations. An extended stellar disk forms inside the Milky Way sized halo immediately after the last major merger. The combination of UV background and SN feedback drastically reduces the number of visible satellites orbiting inside a Milky Way sized halo, bringing it in fair agreement with observations. Our simulations predict that the average age of a primary galaxy's stellar population decreases with mass, because feedback delays star formation in less massive galaxies. Galaxies have stellar masses and current star formation rates as a function of total mass that are in good agreement with observational data. We discuss how both high mass and force resolution and a realistic description of star formation and feedback are important ingredients to match the observed properties of galaxies.Comment: Revised version after the referee's comments. Conclusions unchanged. 2 new plots. MNRAS in press. 20 plots. 21 page

Psychometric evaluation of the functional walking test for children with cerebral palsy.

Purpose. This study examined the psychometric properties of the functional walking test (FWT). Method. Fifty-six subjects with cerebral palsy (CP) (21 females and 35 males, mean age 9 years 6 months, SD 3 years 9months, range 4-17 years) were assessed on two occasions, 6 months apart, using both the FWT and the gross motor function measure (GMFM). Results. Generalisability correlation coefficients (GCC) for all 11 items were high (0.91-0.99). Inter-rater reliability was also high with excellent consensus in the scores given by the eight raters (intra-class correlation coefficient and GCC 0.99). Intra-rater reliability was equally high (GCC 0.99). The internal consistency of the FWT was estimated using Cronbach\u27s α as 0.95 and 0.94 at Time 1 and 2, respectively. The FWT had a high degree of correlation with the GMFM, when total scores were compared at Time 1 and 2 (Pearson\u27s r = 0.86 and 0.87, n = 56, p \u3c 0.01). The FWT also found statistically significant differences in total scores between the three Gross Motor Function Classification System (GMFCS) levels. The correlation between the FWT scores and GMFCS was -0.70 at Time 1 and -0.76 Time 2 (p \u3c 0.01) indicating the construct validity of the FWT. Conclusions. This study has demonstrated that the FWT has sound psychometric properties and is valid and reliable in a sample population of ambulant children with CP

Pragmatic approach to gravitational radiation reaction in binary black holes

We study the relativistic orbit of binary black holes in systems with small mass ratio. The trajectory of the smaller object (another black hole or a neutron star), represented as a particle, is determined by the geodesic equation on the perturbed massive black hole spacetime. The particle itself generates the gravitational perturbations leading to a problem that needs regularization. Here we study perturbations around a Schwarzschild black hole using Moncrief's gauge invariant formalism. We decompose the perturbations into $\ell-$multipoles to show that all $\ell-$metric coefficients are $C^0$ at the location of the particle. Summing over $\ell$, to reconstruct the full metric, gives a formally divergent result. We succeed in bringing this sum to a generalized Riemann's $\zeta-$function regularization scheme and show that this is tantamount to subtract the $\ell\to\infty$ piece to each multipole. We explicitly carry out this regularization and numerically compute the first order geodesics. Application of this method to general orbits around rotating black holes would generate accurate templates for gravitational wave laser interferometric detectors.Comment: 5 pages, 2 figures, improved text and figures. To appear in PR

A Stirling Encounter with Harmonic Numbers

No abstract provided in this article