68,926 research outputs found
Growth history of fault-related folds and interaction with seabed channels in the toe-thrust region of the deep-water Niger delta
The deep-water fold and thrust belt of the southern Niger Delta has prominent thrusts and folds oriented perpendicular to the regional slope that formed as a result of the thin-skinned gravitational collapse of the delta above overpressured shale. The thrust-related folds have grown in the last 12.8 Ma and many of the thrusts are still actively growing and influencing the pathways of modern seabed channels. We use 3D seismic reflection data to constrain and analyse the spatial and temporal variation in shortening of four thrusts and folds having seabed relief in a study area of 2600 km2 size in 2200–3800 m water depth. Using these shortening measurements, we have quantified the variation in strain rates through time for both fault-propagation and detachment folds in the area, and we relate this to submarine channel response. The total amount of shortening on the individual structures investigated ranges from 1 to 4 km, giving a time-averaged maximum shortening rate of between 90 ± 10 and 350 ± 50 m/Myr (0.1 and 0.4 mm/yr). Fold shortening varies both spatially and temporally: The maximum interval shortening rate occurred between 9.5 Ma and 3.7 Ma, and has reduced significantly in the last 3.7 Ma. We suggest that the reduction in the Pliocene-Recent fold shortening rate is a response to the slow-down in extension observed in the up-dip extensional domain of the Niger Delta gravitational system in the same time interval. In the area dominated by the fault-propagation folds, the channels are able to cross the structures, but the detachment fold is a more significant barrier and has caused a channel to divert for 25 km parallel to the fold axis. The two sets of structures have positive bathymetric expressions, with an associated present day uphill slope of between 1.5° and 2°. However, the shorter uphill slopes of the fault-propagation folds and increased sediment blanketing allow channels to cross these structures. Channels that develop coevally with structural growth and that cross structures, do so in positions of recent strain minima and at interval strain rates that are generally less than −0.02 Ma−1 (−1 × 10−16 s−1). However, the broad detachment fold has caused channel diversion at an even lower strain rate of c. −0.002 Ma−1 (−7 × 10−17 s−1)
Ion-scale spectral break of solar wind turbulence at high and low beta
The power spectrum of magnetic fluctuations in the solar wind at 1 AU displays a break between two power laws in the range of spacecraft-frame frequencies 0.1 to 1 Hz. These frequencies correspond to spatial scales in the plasma frame near the proton gyroradius ρi and proton inertial length di. At 1 AU it is difficult to determine which of these is associated with the break, since [Formula: see text] and the perpendicular ion plasma beta is typically β⊥i∼1. To address this, several exceptional intervals with β⊥i≪1 and β⊥i≫1 were investigated, during which these scales were well separated. It was found that for β⊥i≪1 the break occurs at di and for β⊥i≫1 at ρi, i.e., the larger of the two scales. Possible explanations for these results are discussed, including Alfvén wave dispersion, damping, and current sheets
Conditional Image-Text Embedding Networks
This paper presents an approach for grounding phrases in images which jointly
learns multiple text-conditioned embeddings in a single end-to-end model. In
order to differentiate text phrases into semantically distinct subspaces, we
propose a concept weight branch that automatically assigns phrases to
embeddings, whereas prior works predefine such assignments. Our proposed
solution simplifies the representation requirements for individual embeddings
and allows the underrepresented concepts to take advantage of the shared
representations before feeding them into concept-specific layers. Comprehensive
experiments verify the effectiveness of our approach across three phrase
grounding datasets, Flickr30K Entities, ReferIt Game, and Visual Genome, where
we obtain a (resp.) 4%, 3%, and 4% improvement in grounding performance over a
strong region-phrase embedding baseline.Comment: ECCV 2018 accepted pape
Die Entwicklung der Vektorrechnung im französischen Mathematikunterricht seit Ende des 19. Jahrhunderts
Zusammenfassung: Dieser Text ist Teil eines größeren Forschungsprojekts über die Verbindungen zwischen Mathematik und Physik und stellt eine Analyse der Geschichte der Vektorrechnung im Unterricht in Frankreich dar, von ihren ersten Anfängen in der Sekundarstufe am Ende des 19 Jhd. bis zur Gegenwart. Unsere Analyse stützt sich auf einen theoretischen Rahmen, der durch die "Oekologie des Wissens" inspiriert ist (Chevallard, 1994). Über das historische Interesse hinaus wollen wir einen Bereich des Mathematikunterrichtes beleuchten (der unter dem Einfluss der jüngsten Reformen immer kleiner und kleiner wird) sowie seinen Bezug zum Physikunterricht, der - obwohl er von beiden Seiten als natürlich angesehen wird - nicht wirklich als effektive Unterstützung der Lehrer der jeweiligen Disziplin zu dienen schein
iPads, iBooks, Apps! What\u27s all the iFuss about?
The iVolution is here. It is iThis and iThat every way you turn. Is this just another iFad, or is it truly revolutionizing education? In a recent survey conducted by EDUCAUSE Center for Analysis and Research on undergraduates and technology, 31% of students reported owning tablet technology a 15% increase from the previous year and 76% of students reported owning smart phones. This finding was a 14% increase from the previous year. Students also reported using smart devices in class to access material, participate in activities, look up information and photograph material as learning strategies. Thomas Jefferson University is riding the iWave and taking strides to better integrate technology at all levels of medical training; leading the forefront of the iVolution, syllabi, course materials, and textbooks are now delivered in some of our courses via iPads. In the past few years, the Jefferson Health Mentors Program has embraced the use of new technologies, including Wikis, online discussion boards, Google docs, and Skype platforms to facilitate asynchronous IPE interactions. These platforms have helped to promote IPE by easing scheduling logistics and by allowing students to collaborate electronically on team-based assignments. Over the past summer, JCIPE, the Jefferson Health Mentors Program (JHMP), faculty from Jefferson Medical College and the School of Health Professions, Academic & Instructional Support & Resources (AISR) and Jeff Information Technology (IT) assembled a working group and developed yet another innovative tool to better integrate technology into our IPE efforts – the product was a new iBook, entitled “Assessing Patient Safety.
Key physicochemical characteristics governing organic micropollutant adsorption and transport in ion-exchange membranes during reverse electrodialysis
The co-generation of electricity and electrodialysis of seawater in a hybrid system is a promising approach to overcome water scarcity. Reverse electrodialysis harvests energy from the salinity gradient, where seawater is used as a high salinity stream while secondary treated wastewater can be used as a sustainable low salinity stream. Treated wastewater contains organic micropollutants, which can be transported to the seawater stream. The current research establishes a connection between adsorption and transport of organic micropollutants in ion exchange membranes, using a cross-flow stack in adsorption and zero-current experiments. To mimic the composition of treated wastewater, a mixture of nineteen organic micropollutants of varied physicochemical characteristics (e.g. size, charge, polarity, hydrogen donor/acceptor count, hydrophobicity) at environmentally relevant concentrations was used. Depending on the charge, micropollutants develop different types of mechanisms responsible for short-distance interactions with ion-exchange membranes, which has a direct influence in their transport behavior. This study provides a rational basis for the optimization/design of next-generation ion-exchange membranes, in which the permeability toward organic micropollutants should be also included. This investigation highly contributes to understanding the potential hazard posed by organic micropollutants in reverse electrodialysis in seawater desalination systems, where treated wastewater is used as a low salinity stream
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