Data report: Seismic structure beneath the North Cascadia drilling transect of IODP Expedition 311

Between 1999 and 2004, new seismic data became available for the study of gas hydrates on the northern Cascadia margin. These data consist of multi- and single-channel data with two- and partly three-dimensional subsurface coverage and were acquired and used in support of the proposal for Integrated Ocean Drilling Program (IODP) Expedition 311 carried out in 2005. The working area lies across the continental slope off the coast of central Vancouver Island, British Columbia, Canada, with water depths ranging from 2600 m in the trench to 500 m on the upper slope, where it is well above the minimum depth for gas hydrate stability. This paper gives the details of the data acquisition and conventional processing and then focuses on describing the new data at six individual sites along a transect across the gas hydrate zone. Five of the sites were drilled during the Expedition 311. The transect of sites commences at the almost undeformed incoming sediments seaward of the region where gas hydrates are observed; these ocean basin sediments were drilled at a site 40 km southeast during Ocean Drilling Program (ODP) Leg 146. The transect continues up the continental slope into the area of hydrate stability, with a site on top of the frontal accretionary ridge where normal faulting indicates margin parallel extension; a site in the first slope basin overlying a buried ridge near a reflectivity wipe-out zone; a site adjacent to Site 889 of Leg 146 and therefore acting as a tie hole; the most landward site at the shallowest end of the hydrate stability field; and a cold vent site at one of several blank zones close to a bright spot region in the seismic records

Tectonic Consequences of a Uniformly Hot Backarc and Why is the Cordillera Mountain Belt High?

SUMMARYWhy is the North American Cordilleran mountain belt high? We expect a thick crust to support high elevations by isostasy but, remarkably, the Cordilleran crust is thin. There is no crustal root. An important recent recognition is that the high elevation is supported by thermal expansion rather than by thickened crust. The elevation of the Cordillera is only one consequence of the Cordillera being uniformly hot and having a thin lithosphere, in common with most current or recent backarcs. Some other consequences of the high temperatures compared to the adjacent cool craton include: (1) The Cordillera and other backarcs are hot, weak mobile belts that can be deformed by available plate-tectonic forces, in contrast to stable cratons that cannot; (2) Most continental seismicity is concentrated in backarcs; (3) In the Cordillera there is widespread sporadic ‘backarc’ volcanism; (4) The high temperatures result in very low strength in the lower crust that allows lower-crust detachment; (5) The lower crust weakness facilitates large-scale crustal oroclines that may be independent of the upper mantle; (6) The lower crust in the Cordillera and other backarcs is in amphibolite- to granulite-facies conditions, ~800–900°C at the Moho; (7) In ancient backarcs globally, regional Barrovian metamorphism is concluded to be the result of high temperatures that predate the orogenic collision and deformation. No "heat of orogeny" is required. Following the termination of subduction, backarcs cool with a time constant of 300–500 m.y.RÉSUMÉPourquoi la chaîne de montagnes de la Cordillère nord-américaine est-elle si haute? On comprend qu’une croûte sur-épaisse puisse expliquer une grande élévation, mais voilà, la croûte de la Cordillère est mince. Il n’existe pas de racine crustale. Or, récemment, une conclusion importante s’est imposée, soit que cette haute élévation s’explique par l’expansion thermique plutôt que par l’existence d’une croûte sur-épaisse. L’élévation de la Cordillère n’est qu’une des conséquences d’une Cordillère uniformément chaude flottant sur une lithosphère mince, caractéristiques communes aux zones d’arrière-arc actuelles ou récentes. Quelques unes des autres conséquences de cette haute température, par opposition aux froids cratons adjacents, comprennent: (1) La Cordillère et d’autres zones d’arrières-arcs sont des zones chaudes et facilement déformables par les forces tectoniques ambiantes, contrairement aux cratons stables; (2) La majorité de l’activité sismique continentale est concentrée dans le zones d’arrière-arc; (3) Dans la Cordillère l’activité volcanique sporadique est généralisé; (4) Ces températures élevées explique la très faible rigidité de la croûte inférieure et les décollements qu’elle subit; (5) La flaccidité de la croûte inférieure facilite la formation d’oroclinaux de grandes magnitudes qui peuvent être indépendants du manteau supérieur; (6) La croûte inférieure de la Cordillère et d’autres zones d’arrière-arc sont dans la zone de faciès amphibolite à granulite, soit 800 à 900oC à la discontinuité Moho; (7) Globalement dans les anciennes zones d’arrière-arc, le métamorphisme régional barrovien s’explique alors comme étant le résultat des hautes températures antérieures à la collision et à la déformation orogénique. Aucune « chaleur orogénique » n’est nécessaire. Après la période de subduction, les zones d’arrière-arc se refroidissent à l’intérieur d’un intervalle de temps de 300 à 500  millions d’années

No Money, Mo' Problems: The Role of the Remix in Restructuring Compensation for Producers of Electronic Dance Music

Based on fieldwork conducted between March and November 2011, this article argues that the popularity of remixing has led to a restructuring of compensation for producers of remixes within the context of electronic dance music (EDM). This article presents the different ways producers of EDM are currently compensated for their remixes, and how this compensation differs from the payment and intellectual property protections given for the composition of original songs. This article concludes by discussing how these producers are beginning to negotiate deals with labels and artists that will result in greater financial security and better protection of remixers' intellectual property rights.En se basant sur un travail de terrain effectué entre mars et novembre 2011, cet article a pour argument que la popularité du remix a conduit à la restructuration des revenus de ceux qui en produisent dans le contexte de l'electronic dance music, ou techno. Cet article présente les différents moyens par lesquels les producteurs de techno perçoivent des revenus pour leurs remix, et la façon dont ces indemnisations diffèrent des redevances et des protections de propriété intellectuelle obtenues pour la composition de chansons originales. Cet article se conclut par une discussion de la façon dont ces producteurs commencent à négocier des contrats avec les maisons de disques et les artistes afin de s'assurer une plus grande sécurité financière et une meilleure protection de leurs droits de propriété intellectuelle

The vector innovation structural time series framework: a simple approach to multivariate forecasting

The vector innovation structural time series framework is proposed as a way of modelling a set of related time series. Like all multi-series approaches, the aim is to exploit potential inter-series dependencies to improve the fit and forecasts. A key feature of the framework is that the series are decomposed into common components such as trend and seasonal effects. Equations that describe the evolution of these components through time are used as the sole way of representing the inter-temporal dependencies. The approach is illustrated on a bivariate data set comprising Australian exchange rates of the UK pound and US dollar. Its forecasting capacity is compared to other common single- and multi-series approaches in an experiment using time series from a large macroeconomic database.Vector innovation structural time series, state space model, multivariate time series, exponential smoothing, forecast comparison, vector autoregression.

The Challenge of Deep Ocean Drilling for Natural Gas Hydrate

Large reservoirs of natural gas hydrate have been sampled extensively by past DSDP, ODP, and other scientific ocean drilling. Gas hydrate is an ice-like solid consisting of gas molecules, commonly methane, trapped in a cage of water molecules. Global estimates of the methane content of natural gas hydrate are very large, potentially enormous. Such large quantities of gas hydrate could be important as a clean energy source, as a control in global climate, and as a factor in seafloor slumps and slides. Gas hydrate occurs only in water depths greater than about 600 m at temperate latitudes, but occurs on land and in shallow water in the Arctic. The formation mechanisms of gas hydrates are only partly understood. Gas hydrate appears to be formed usually by migrating fluids carrying biologically generated methane upward to regions of sufficiently low temperature and high pressure where the hydrate is stable. Quantitative aspects of this formation model need testing, however, and questions remain about the sources and sinks for methane, and the amount that can reach the atmosphere. In Canada, gas hydrates are found on most of its continental margins, notably on the continental slope off Vancouver Island and in the Mackenzie Delta-Beaufort Sea region. A drilling program off Vancouver Island would examine gas hydrates in a well-studied accretionary sedimentary wedge; such sediments appear to be the most common environment in which hydrates are found globally. Drilling for gas hydrate offshore in the Canadian Arctic, perhaps using an alternative drilling platform, would complement a current onshore Arctic gas hydrate drilling program in the permafrost environment. The Arctic land and shallow sea hydrate are important because such hydrate is especially susceptible to global climate change. Résumé De vastes réservoirs d'hydrate de gaz naturel ont été amplement échantillonnés par le DSDP, l'ODP et d'autres programmes de forage scientifiques. L'hydrate de gaz est un solide semblable à la glace, constitué de molécules de gaz, généralement du méthane, piégées dans une cage de molécules d'eau. Les estimations des volumes planétaires d'hydrate de gaz naturel sont très grandes, voire énormes. De telles quantités d'hydrate de gaz pourraient s'avérer important comme source d'énergie, comme tampon de régulation du climat de la planète, et comme facteur dans les mouvements et les glissements de terrains des fonds marins. Sous l'eau, les hydrate de gaz n'existent qu'à des profondeurs de plus de 600 m aux latitudes tempérées, mais ils existent sur terre et en eaux peu profondes dans les régions arctiques. Le mécanisme de formation des hydrates de gaz n'est que partiellement élucidé. Il semble que l'hydrate de gaz se forme généralement par la migration ascendante de fluides porteurs de méthane biologique vers des zones de température suffisamment basse et de pression suffisamment élevée, là où l'hydrate est stable. Cependant, les aspects quantitatifs de ce modèle de formation doivent être vérifiés, et certaines questions demeurent sans réponse quant aux sources et aux pièges du méthane, et à la quantité pouvant atteindre l'atmosphère. Au Canada, on trouve de l'hydrate de gaz sur la plupart de ses marges continentales, notamment sur la pente continentale au large de l'île de Vancouver de même que dans la zone du delta du Mackensie-mer de Beaufort. Un programme de forage au large de l'île de Vancouver permettrait d'étudier les hydrates de gaz au sein d'un biseau sédimentaire d'accrétion bien étudié; il semble que ce type de sédiments soit l'environnement le plus commun où l'on trouve des hydrates de gaz sur la planète. Le forage de prospection en mer pour l'hydrate de gaz dans l'Arctique canadien, peut-être avec une autre plateforme de forage, permettrait de compléter un programme de forage sur les hydrates de gaz en cours dans une région arctique du continent, dans un environnement de pergélîsol. L'hydrate de gaz des terres de l'Arctique et des mers peu profondes est important à cause de sa susceptibilité aux changements climatiques planétaires

From Zero to Over 2,500 Eportfolios in Six Years: The Eastern Kentucky University Experience

In 2000, Eastern Kentucky University (EKU) was awarded a Preparing Tomorrows Teachers to Use Technology (PT3) Implementation grant. One of the major goals of the grant was to create an electronic/multimedia portfolio (eportfolio) assessment system through which future teachers would document their proficiencies and amass strategies to enhance their future teaching. Between the fall of 2000 and the summer of 2003 an eportfolio development team, consisting of faculty from the College of Education and the College of Arts and Sciences, a college student, a public school teacher, and a technology expert, developed and implemented an eportfolio to be used by all teacher education candidates in the College of Education. Through systematic piloting and review, the obstacles and challenges of developing an eportfolio were met and a professional product was incorporated into the teacher education program in the College of Education. As of spring 2006, over 2,500 College of Education student eportfolios are online

Exponential Smoothing for Inventory Control: Means and Variances of Lead-Time Demand

Exponential smoothing is often used to forecast lead-time demand for inventory control. In this paper, formulae are provided for calculating means and variances of lead-time demand for a wide variety of exponential smoothing methods. A feature of many of the formulae is that variances, as well as the means, depend on trends and seasonal effects. Thus, these formulae provide the opportunity to implement methods that ensure that safety stocks adjust to changes in trend or changes in season.Forecasting; inventory control; lead-time demand; exponential smoothing; forecast variance.

Monitoring Processes with Changing Variances

Statistical process control (SPC) has evolved beyond its classical applications in manufacturing to monitoring economic and social phenomena. This extension requires consideration of autocorrelated and possibly non-stationary time series. Less attention has been paid to the possibility that the variance of the process may also change over time. In this paper we use the innovations state space modeling framework to develop conditionally heteroscedastic models. We provide examples to show that the incorrect use of homoscedastic models may lead to erroneous decisions about the nature of the process. The framework is extended to include counts data, when we also introduce a new type of chart, the P-value chart, to accommodate the changes in distributional form from one period to the next.Control charts, count data, GARCH, heteroscedasticity, innovations, state space, statistical process control