Death: A Philosophical Perspective on the Legal Definitions

In light of semantic and ethical requirements developed from a consideration of the problems and interests surrounding the definitional debate, the Article evaluates the various definitions of death recently set forth by state legislatures, courts, and professional organizations, all of which equate human death with a physiological state of one kind or another. In turn, a definition of human death on a psychological plane that identifies death with the permanent loss of all consciousness is recommended for public acceptance. Accordingly, certain physiological states, such as the functional disintegration of the brain (or of the brain cortex alone), become empirically established indicators (diagnostic criteria) of the occurrence of human death in the psychological sense

Effect of picosecond strain pulses on thin layers of the ferromagnetic semiconductor (Ga,Mn)(As,P)

The effect of picosecond acoustic strain pulses (ps-ASP) on a thin layer of (Ga,Mn)As co-doped with phosphorus was probed using magneto-optical Kerr effect (MOKE). A transient MOKE signal followed by low amplitude oscillations was evidenced, with a strong dependence on applied magnetic field, temperature and ps-ASP amplitude. Careful interferometric measurement of the layer's thickness variation induced by the ps-ASP allowed us to model very accurately the resulting signal, and interpret it as the strain modulated reflectivity (differing for $\sigma_{\pm}$ probe polarizations), independently from dynamic magnetization effects.Comment: 6 pages, 5 figure

Ultrafast Molecular Imaging by Laser Induced Electron Diffraction

We address the feasibility of imaging geometric and orbital structure of a polyatomic molecule on an attosecond time-scale using the laser induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO2 molecule excited by a near infrared few-cycle laser pulse. The molecular geometry (bond-lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms

Détermination à l'aide d'un modèle récepteur des zones sources à l'origine des concentrations mesurées dans les précipitations collectées en trois sites du réseau MERA (France)

Ces travaux s'inscrivent dans le cadre du programme national de MEsure des Retombées Atmosphériques (MERA). Ils portent sur la recherche de l'origine des précipitations collectées entre 1997 et 1999 dans trois (Morvan, Iraty, Le Casset) des onze stations du réseau MERA localisées en différents points du territoire français. Deux méthodes statistiques ont été utilisées dans cette étude. Les régions à l'origine des fortes concentrations mesurées au site récepteur ont d'abord été déterminées à l'aide d'un modèle (méthode de Seibert) combinant les mesures réalisées sur site et les rétrotrajectoires de masses d'air puis, dans un second temps les différents profils de transport atmosphérique, leur fréquence et concentrations associées ont été évaluées à l'aide d'une classification par Nuées Dynamiques (méthode K-means/distance Euclidienne simple) des rétrotrajectoires de masses d'air. Le test de Kruskal-Wallis a été utilisé pour vérifier si les médianes des concentrations associées à chaque classe sont statistiquement différentes. L'étude réalisée à Iraty (Pyrénées) et au Casset (Alpes) a montré que ces deux stations sont influencées différemment du Morvan. Plus exactement, ces deux sites ne sont pas, ou pratiquement pas, influencés par les zones d'Europe centrale ou du Nord-Ouest fortement émettrices de SO2, de NOx et de NH3. Seul le pH des précipitations collectées à Iraty semble dépendre des émissions de SO2 et de NOx d'une de ces zones. Iraty et le Casset sont très influencées par les émissions anthropiques et par les poussières d'origine terrestres en provenance d'Afrique du Nord. Néanmoins, les niveaux de concentrations mesurés dans les flux en provenance d'Afrique du Nord sont similaires pour Iraty, le Casset et le Morvan (sauf en ions calcium, pour lequel le Casset et Iraty montrent de fortes concentrations). Une autre région européenne peut influencer les niveaux en composés acidifiants mesurés au Casset, il s'agit de l'Italie et de la zone localisée au niveau de l'ex-Yougoslavie. Mais, les niveaux de concentrations qui en résultent sont faibles par rapport à ceux mesurés dans certains flux arrivant au Morvan.The chemistry of precipitation in France was examined using data from the French atmospheric deposition network (MERA). In order to examine the source-receptor relationships responsible for acid rain at three background sites in France, a receptor-oriented model was applied to the precipitation data collected from 1997 to 1999. This methodology combined precipitation and chemical data with air parcel backward trajectories to establish concentration field maps of likely contributing sources. Then, a clustering technique using partitioning methods (K-means/Euclidian distance) was performed to backward trajectories and the distributions of mixing samples associated with backward trajectories in each cluster were compared. The Kruskal-Wallis test was used to verify that the concentration medians associated with each cluster were statistically significant. The results of this study demonstrated that two stations (Iraty and le Casset) were not influenced by the same sources as Morvan. Specifically, these sites were less influenced by high emissions from Central or Northwestern Europe when compared to Morvan. Only the pH seemed under the influence of SO2 and NOx emissions from one of these areas. Iraty and Le casset are very influenced by anthropogenic emissions and the crustal sources around the Mediterranean Basin and North Africa. Other European areas (e.g. Italy) can influence the concentrations recorded at Le Casset but the levels of concentration are lower than those measured at Morvan.This paper represents a complete statistical analysis of wet-only deposition chemistry data for three stations (Iraty, Le Casset and Morvan). Two statistical methods were used in this study. In order to examine the source-receptor relationships responsible for acid rain at these three background sites in France, a receptor-oriented model was applied to the precipitation data collected from 1997 to 1999. This methodology combined chemical data with air parcel backward trajectories to establish concentration field maps of likely contributing sources. This receptor-oriented model was developed by Seibert and it assumes that if a trajectory endpoint falls in a grid cell (i,j), the air mass is assumed to collect components emitted in this cell and once the components are incorporated, they are transported along the trajectory to the receptor site. This model doesn't take into account the atmospheric diffusion and the removal mechanisms occurring during the trajectory from the sources to the receptor. Finally, a concentration field map for the selected species was calculated taking into account all grid cells. For mapping, the grid cells counting fewer than 10 endpoints were not taken in consideration because the confidence of their results was considered too low. The role of three-dimensional backward trajectories is fundamental, so we used three different information sources: the French Institute of Meteorology, Météo-France; the British Atmospheric Data Centre (BADC); and the Atmospheric Environment Service Long Range Transport model of Air Pollution (AES-LRTAP), Canada. These trajectory models were compared for different chemical species. All data were projected in the EMEP grid (150 x 150 km) for establishment of the concentration field map. A clustering technique by partitioning methods (K-means/Euclidian distance) was performed on backward trajectories and the distributions of mixing samples associated with backward trajectories in each cluster were compared. The Kruskal-Wallis test was used to verify that the median concentrations associated with each cluster were statistically significant.The results of this study for Morvan determined five classes of backward trajectories associated with the precipitation collected at this station located in the centre of France. The fluxes from SW and WSW sectors contribute for 52% of events, while the fluxes of NW and E contribute for 31% of events but are mainly responsible for high concentrations of sulphates, nitrates, ammonium and hydronium ion. Regions found to be responsible for rain events coincide with European regions known for their high anthropogenic emissions of SO2 and NOx (Great Britain, North of France, Belgium, The Netherlands and the North of sea).The results for Iraty (South of France) yielded five classes of backward trajectories associated with the precipitation collected in this station. The fluxes from W sectors (NNW, NW, W and WSW) were responsible for 71% of events, while the flux of S (low wind) was responsible for 29% of events but is mainly responsible for high concentrations of sulphates, nitrates, ammonium and calcium. High concentrations of hydronium ion were identified in the NNW sector.The results for Le Casset (East region and mountainous) gave four classes of backward trajectories associated with the precipitation collected in this station. The fluxes from W and WSW sectors were responsible for 35% of events, while the flux of SSW was responsible for 43% and the flux from the SE was responsible for 22% of events. This last sector was mainly responsible for high concentrations of sulphates, nitrates, ammonium and calcium. The concentrations measured at this station were low. Regions found to be responsible for rain events coincide with southern and eastern areas known for their high anthropogenic emissions of SO2 and NOx (north Africa, northern Italy, Yugoslavia).All these results demonstrate that the Iraty and Le Casset stations were not influenced by the same sources as Morvan. Specifically, these sites were less influenced by the high emissions from central or northwestern Europe than Morvan. Only the measurement of pH seemed to be under the influence of SO2 and NOx emissions of one of these areas. Iraty and Le Casset were very influenced by the anthropogenic emissions and the crustal sources around the Mediterranean Basin and North Africa. Other European areas (e.g., Italy) can influence the concentrations recorded at Le Casset but the levels were lower than those measured at Morvan. A relation between sulphates, nitrates and ammonium was identified for Morvan and Le Casset. This observation suggests that aerosol transport of NH4 HSO4, (NH4)2 SO4 and NH4 NO3 is occurring

Probably Safe or Live

This paper presents a formal characterisation of safety and liveness properties \`a la Alpern and Schneider for fully probabilistic systems. As for the classical setting, it is established that any (probabilistic tree) property is equivalent to a conjunction of a safety and liveness property. A simple algorithm is provided to obtain such property decomposition for flat probabilistic CTL (PCTL). A safe fragment of PCTL is identified that provides a sound and complete characterisation of safety properties. For liveness properties, we provide two PCTL fragments, a sound and a complete one. We show that safety properties only have finite counterexamples, whereas liveness properties have none. We compare our characterisation for qualitative properties with the one for branching time properties by Manolios and Trefler, and present sound and complete PCTL fragments for characterising the notions of strong safety and absolute liveness coined by Sistla

Topographical coloured plasmonic coins

The use of metal nanostructures for colourization has attracted a great deal of interest with the recent developments in plasmonics. However, the current top-down colourization methods based on plasmonic concepts are tedious and time consuming, and thus unviable for large-scale industrial applications. Here we show a bottom-up approach where, upon picosecond laser exposure, a full colour palette independent of viewing angle can be created on noble metals. We show that colours are related to a single laser processing parameter, the total accumulated fluence, which makes this process suitable for high throughput industrial applications. Statistical image analyses of the laser irradiated surfaces reveal various distributions of nanoparticle sizes which control colour. Quantitative comparisons between experiments and large-scale finite-difference time-domain computations, demonstrate that colours are produced by selective absorption phenomena in heterogeneous nanoclusters. Plasmonic cluster resonances are thus found to play the key role in colour formation.Comment: 9 pages, 5 figure

Laser induced electron diffraction: a tool for molecular orbital imaging

We explore the laser-induced ionization dynamics of N2 and CO2 molecules subjected to a few-cycle, linearly polarized, 800\,nm laser pulse using effective two-dimensional single active electron time-dependent quantum simulations. We show that the electron recollision process taking place after an initial tunnel ionization stage results in quantum interference patterns in the energy resolved photo-electron signals. If the molecule is initially aligned perpendicular to the field polarization, the position and relative heights of the associated fringes can be related to the molecular geometrical and orbital structure, using a simple inversion algorithm which takes into account the symmetry of the initial molecular orbital from which the ionized electron is produced. We show that it is possible to extract inter-atomic distances in the molecule from an averaged photon-electron signal with an accuracy of a few percents

Theoretical analysis of the implementation of a quantum phase gate with neutral atoms on atom chips

We present a detailed, realistic analysis of the implementation of a proposal for a quantum phase gate based on atomic vibrational states, specializing it to neutral rubidium atoms on atom chips. We show how to create a double--well potential with static currents on the atom chips, using for all relevant parameters values that are achieved with present technology. The potential barrier between the two wells can be modified by varying the currents in order to realize a quantum phase gate for qubit states encoded in the atomic external degree of freedom. The gate performance is analyzed through numerical simulations; the operation time is ~10 ms with a performance fidelity above 99.9%. For storage of the state between the operations the qubit state can be transferred efficiently via Raman transitions to two hyperfine states, where its decoherence is strongly inhibited. In addition we discuss the limits imposed by the proximity of the surface to the gate fidelity.Comment: 9 pages, 5 color figure

On reducing the complexity of matrix clocks

Matrix clocks are a generalization of the notion of vector clocks that allows the local representation of causal precedence to reach into an asynchronous distributed computation's past with depth $x$, where $x\ge 1$ is an integer. Maintaining matrix clocks correctly in a system of $n$ nodes requires that everymessage be accompanied by $O(n^x)$ numbers, which reflects an exponential dependency of the complexity of matrix clocks upon the desired depth $x$. We introduce a novel type of matrix clock, one that requires only $nx$ numbers to be attached to each message while maintaining what for many applications may be the most significant portion of the information that the original matrix clock carries. In order to illustrate the new clock's applicability, we demonstrate its use in the monitoring of certain resource-sharing computations