1,912 research outputs found
Legal approaches to management of the risk of cloud computing insolvencies
Cloud computing has revolutionised data handling in recent years in enabling the usage of computing resources, including for the storage of data, through flexible and on-demand services, often accessed through the internet. One potential consequential challenge which has only been briefly touched upon previously is the containment of the impact of an insolvency in this area, as access to data, as well as the means of processing this data, may be significantly delayed or even lost upon the failure of a cloud service provider. This is a matter of serious concern, as growing reliance on cloud computing technologies by businesses, including financial institutions, as well as public authorities presents risks of an insolvency having a potentially systemic nature. This article represents an initial attempt to identify possible approaches to the threat of cloud computing insolvencies, suggesting a double layered domestic approach in view of the significant risks for businesses and potential variations in scale and impact, as well as a need for supranational approach given the potential for a 'too big to fail' scenario. Lying at the intersection of insolvency law and technological innovation this is an area which is as yet almost entirely unexplored
Responses of salmonids to habitat changes
Streams in western North America provide spawning and rearing habitats for several species of salmon and trout that are of substantial economic importance in the region. Timber that grows on lands through which these streams flow is also economically important, and its harvest can substantially change habitat conditions and aquatic production in salmonid streams. Undisturbed forests, the streams that flow through them, and the salmonid communities in these streams have intrinsic scientific, genetic, and cultural values in addition to their economic importance. The complex relations between salmonids and their physical environment, and the changes in these relations brought about by timber harvest, have been investigated extensively (see the bibliography by Macdonald et al. 1988). However, in spite of considerable evidence of profound changes in channel morphology and in light, temperature, and flow regimes associated with timber harvests, much uncertainty exists about the responses of salmonids to these changes
Analyse centrographique de la population du Québec de 1951 à 1971
Avant de pouvoir expliquer les processus qui sous-tendent la redistribution de la population, il est trĂšs utile de dĂ©celer les tendances gĂ©nĂ©rales de cette redistribution. L'un des meilleurs outils Ă cette fin est l'analyse centrographique. Trois mesures centro-graphiques : le centre de gravitĂ©, la distance-type et un indice de dispersion relative, sont calculĂ©es pour la rĂ©partition de la population du QuĂ©bec Ă trois Ă©chelles diffĂ©rentes (division de recensement, rĂ©gion administrative et province) Ă trois points dans le temps (1951, 1961, 1971). Au premier niveau, la grande majoritĂ© des divisions de recensement sont caractĂ©risĂ©es par la stabilitĂ© ou par une tendance Ă la concentration. Au niveau rĂ©gional, la population tend Ă se concentrer dans toutes les rĂ©gions administratives sauf deux : l'Abitibi et la GaspĂ©sie. Au niveau de l'ensemble du QuĂ©bec, il y a eu tendance Ă la concentration, le centre de gravitĂ© se situant dans le lac Saint-Pierre, au nord de la municipalitĂ© de Nicolet, mais se dĂ©plaçant progressivement vers MontrĂ©al.A first step in explaining the processes which result in a redistribution of population over time is the identification of patterns and trends. A very useful tool to this end is centrographic analysis. The centrographic measures, centre of gravity, standard distance and a measure of relative dispersion, are determined for the population distribution of QuĂ©bec at varying scales (county, region, province) for three points in time (1951, 1961, 1971). At the first level, the large majority of the counties either exhibited stable patterns or tended toward concentration. At the regional level, population tended to concentrate in all but two of the administrative regions studied â Abitibi and GaspĂ©sie. At the provincial level, there has been a general trend toward concentration. The centre of gravity of the population, while remaining in the environs of the municipality of Nicolet, is wending its way progressively toward MontrĂ©al
Material Characterization and Real-Time Wear Evaluation of Pistons and Cylinder Liners of the Tiger 131 Military Tank
Material characterisation and wear evaluation of the original and replacement pistons and cylinder-liners of Tiger 131 is reported. Original piston and cylinder-liner were operative in the Tigersâ engine during WWII. The replacement piston and cylinder-liner were used as substitutes and were obtained after failure in two hours of operation in the actual engine. Material characterisation revealed that the original piston was aluminium silicon hypereutectic alloy whereas the replacement piston was aluminium copper alloy with very low silicon content. Both original and replacement cylinder-liners consisted of mostly iron which is indicative of cast iron, a common material for this application. The replacement piston average surface roughness was found to be 9.09 ÎŒm while for replacement cylinder-liner it was 5.78 ÎŒm
Hedgehog Signalling in Androgen Independent Prostate Cancer
Objectives: Androgen-deprivation therapy effectively shrinks hormone-naĂŻve prostate cancer, both in the prostate and at sites of distant metastasis. However prolonged androgen deprivation generally results in relapse and androgen-independent tumour growth, which is inevitably fatal. The molecular events that enable prostate cancer cells to proliferate in reduced androgen conditions are poorly understood. Here we investigate the role of Hedgehog signalling in androgen-independent prostate cancer (AIPC). Methods: Activity of the Hedgehog signalling pathway was analysed in cultured prostate cancer cells, and circulating prostate tumour cells were isolated from blood samples of patients with AIPC. Results: AIPC cells were derived through prolonged culture in reduced androgen conditions, modelling hormone therapy in patients, and expressed increased levels of Hedgehog signalling proteins. Exposure of cultured AIPC cells to cyclopamine, which inhibits Hedgehog signalling, resulted in inhibition of cancer cell growth. The expression of the Hedgehog receptor PTCH and the highly prostate cancer-specific gene DD3PCA3 was significantly higher in circulating prostate cancer cells isolated from patients with AIPC compared with samples prepared from normal individuals. There was an association between PTCH and DD3PCA3 expression and the length of androgen-ablation therapy. Conclusions: Our data are consistent with reports implicating overactivity of Hedgehog signalling in prostate cancer and suggest that Hedgehog signalling contributes to the androgen-independent growth of prostate cancer cells. As systemic anti-Hedgehog medicines are developed, the Hedgehog pathway will become a potential new therapeutic target in advanced prostate cancer.Peer reviewedFinal Accepted Versio
Performance modeling of ultraviolet Raman lidar systems for daytime profiling of atmospheric water vapor
We describe preliminary results from a comprehensive computer model developed to guide optimization of a Raman lidar system for measuring daytime profiles of atmospheric water vapor, emphasizing an ultraviolet, solar-blind approach
The sticking probability of D2O-water on ice: Isotope effects and the influence of vibrational excitation
International audienceThe present study measures the sticking probability of heavy water (D2O) on H2O- and on D2O-ice and probes the influence of selective OD-stretch excitation on D2O sticking on these ices. Molecular beam techniques are combined with infrared laser excitation to allow for precise control of incident angle, translational energy, and vibrational state of the incident molecules. For a translational energy of 69 kJ/mol and large incident angles (Ξ â„ 45°), the sticking probability of D2O on H2O-ice was found to be 1% lower than on D2O-ice. OD-stretch excitation by IR laser pumping of the incident D2O molecules produces no detectable change of the D2O sticking probability (<10â3). The results are compared with other gas/surface systems for which the effect of vibrational excitation on trapping has been probed experimentally
Volcaniclastic debris flow occurrences in the Campania region (southern Italy) and their relation to Holocene - late Pleistocene pyroclastic fall deposits: implications for large scale hazard mapping
The Campania Region (Southern Italy) is characterized by the frequent occurrence of volcaniclastic
debris flows that produce damage to property and loss of life (more than 170 deaths between 1996
and 1999). Historical investigation allowed the identification of more than 500 events during the
last four centuries; in particular, more than half of these occurred in the last 100 years, causing
hundreds of deaths. The aim of this paper is to identify debris flow proneness and to quantify
hazard. To this end, we compared several elements such as the thickness distribution of pyroclastic
fall deposits from the last 18 ka of the Vesuvius and Phlegrean Fields volcanoes, the slopes of
relieves, and the historical record of volcaniclastic debris flows from AD 1500 to the present.
Results show that flow occurrence is not only a function of the cumulative thickness of past
pyroclastic fall deposits but also depends on the age of emplacement. Deposits younger than 10 ka
(Holocene eruptions) apparently increase the risk of debris flows, while those older than 10 ka (Late
Pleistocene eruptions) seem to play a less prominent role. This is probably in relation to different climatic conditions, and therefore different rates of erosion of pyroclastic falls between the
Holocene and the Late Pleistocene. Based on the above considerations, we compiled a large-scale
debris flow hazard map of the study area in which five main hazard zones are identified: very low,
low, moderate, high and very high
Estimation de l'Ă©quivalent en eau du couvert nival au moyen d'images radar satellitaires
L'objectif de cette Ă©tude est de vĂ©rifier le potentiel des images radar Ă synthĂšse d'ouverture (RSO) pour estimer l'Ă©quivalent en eau du couvert nival sur le bassin de la riviĂšre La Grande (Baie de James, QuĂ©bec). Il s'agit d'un milieu dominĂ© par une forĂȘt ouverte d'Ă©pinettes noires, des brĂ»lis et des tourbiĂšres. Cette information intĂ©resse grandement Hydro-QuĂ©bec qui gĂšre plusieurs installations hydro-Ă©lectriques dans cette rĂ©gion subarctique. Durant deux ans, six campagnes de terrain ont Ă©tĂ© rĂ©alisĂ©es sur le bassin de la riviĂšre La Grande et une dizaine d'images RSO du satellite europĂ©en ERS-1 ont Ă©tĂ© acquises, Ă©talonnĂ©es et gĂ©orĂ©fĂ©rencĂ©es, afin de dĂ©terminer la relation entre les coefficients de rĂ©trodiffusion des images radar (hiver et automne) et la rĂ©sistance thermique du couvert nival. Cette relation constitue la premiĂšre partie d'un algorithme d'estimation de l'Ă©quivalent en eau. Elle utilise plus spĂ©cifiquement le rapport de rĂ©trodiffusion, qui est la diffĂ©rence entre une image avec neige et une image sans neige. La deuxiĂšme partie de cette algorithme dĂ©duit l'Ă©quivalent en eau du couvert de neige Ă partir de sa rĂ©sistance thermique et de sa densitĂ©, en se basant sur la relation physique Ă©tablie par les mesures de terrain. L'Ă©quivalent en eau du couvert nival a donc Ă©tĂ© estimĂ© pour quatre images de fĂ©vrier et mars 1994 et 1995. L'erreur moyenne sur l'estimation de l'Ă©quivalent en eau de la neige au sol est de 2% Ă 3% (-5 Ă 7mm) sur l'ensemble des sites d'Ă©chantillonnage avec un Ă©cart-type de 14 Ă 19% (-35 Ă 45mm). Ces rĂ©sultats ont encouragĂ© Hydro-QuĂ©bec Ă poursuivre la recherche avec les donnĂ©es du satellite canadien RADARSAT (opĂ©rationnel depuis le 1er avril 1996) et Ă dĂ©velopper un prototype pour la cartographie de l'Ă©quivalent en eau du couvert nival Ă partir d'images radar.The goal of this study was to evaluate the potential of synthetic aperture radar (SAR) images for estimating the snow water equivalent (SWE) on the La Grande river watershed (James Bay area, QuĂ©bec). This information is of major interest for Hydro-QuĂ©bec, which exploits many hydroelectric complexes throughout this subarctic region. The La Grande watershed is composed of moderately dense to opened black spruce forests, opened areas, burned areas and peat bogs. Over two years (1994-1995), six field campaigns were carried out on a study site located between the LG4 and Laforge1 reservoir, in the center of the La Grande river watershed. The field measurements were of two types: 20 snow lines (depth, snow water equivalent (SWE), density) and 8 snow profiles (depth, density, grain size, temperature, dielectric constant). With these data, the thermal resistance of the snowpack was calculated for every test-site, using the depth, density and thermal conductivity of each layer. Concurrently, more than 10 SAR images (European Satellite ERS-1) of the study site were acquired, calibrated and georeferenced. The backscattering coefficients of all winter images were extracted. Using a reference image (snow-free), backscattering ratios were calculated. They are the difference between a winter image and a snow-free image. This process is used to reduce the impact of vegetation and topography. Then, the relationship between the backscattering ratios and the snowpack thermal resistance of february and march 1994 are established, as the first part of an algorithm developed to estimate the snow water equivalent. The second part of the algorithm infers the snowpack water equivalent from its thermal resistance and density, based on the physical relationship established with field data. This approach is based on studies conducted by INRS-Eau in a southern Quebec agricultural area (BERNIER and FORTIN (1998)). The hypothesis are based on the following: - The snowpack characteristics influence the underlying soil temperature;- The dielectric constant of the soil varies with the soil temperature under 0°C;- The radar signal is influenced by the soil dielectric constant;- Thus, the snowpack characteristics (thermal resistance) influence the radar signal. However, due to variations of soil humidity on the date of the reference image (september 1994), two slightly different relationships were obtained. One for open areas and open forests and one for burned areas and peat bogs. This shows the importance of using a good reference image, with homogeneous soil conditions. It could be better to obtain an image later in the fall, when the soil is frozen. The relationships established here are preliminary, as they use a small dataset. It is estimated that a better regression should be obtained with the acquisition of more images and with a greater range of snow characteristics. However, the algorithm is applied to test the applicability of the method. First, the algorithm was applied on the test-sites, using the images from February and March of 1994 and 1995. The mean error on the estimation of the snow water equivalent is 2% to 3% ( 5 to 7mm), with a deviation of 14% to 19% ( 35 to 45mm). The results are comparable for both years, even if the algorithm is based on 1994 data only. Secondly, the algorithm is applied on the whole images. A classification of a Landsat-TM image is used to identify the land cover of every pixel, which determines the regression and the snow density to be used in the algorithm. Four maps of the SWE are produced and resampled to a resolution of 500m. These are compared with the field measurements from the four nearest Hydro-Quebec snow survey sites. The SWE measured by Hydro-Quebec are all within the most dominant SWE class of each map. Further validation of the results will be possible when the algorithm can be applied on a sub-watershed, which is the actual scale used by Hydro-Quebec. However, the results of this study were sufficiently promising to Hydro-Quebec to support a follow up research with data from the canadian satellite RADARSAT (operational since april 1996). Meanwhile, to improve the algorithm, it is important to obtain a good and homogeneous reference image, to better assess the impact of the land cover and to acquire a dataset with a greater range of snow characteristics
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