415 research outputs found
Sinusoidally-Modulated Graphene Leaky-Wave Antenna for Electronic Beamscanning at THz
This paper proposes the concept, analysis and design of a
sinusoidally-modulated graphene leaky-wave antenna with beam scanning
capabilities at a fixed frequency. The antenna operates at terahertz
frequencies and is composed of a graphene sheet transferred onto a
back-metallized substrate and a set of polysilicon DC gating pads located
beneath it. In order to create a leaky-mode, the graphene surface reactance is
sinusoidally-modulated via graphene's field effect by applying adequate DC bias
voltages to the different gating pads. The pointing angle and leakage rate can
be dynamically controlled by adjusting the applied voltages, providing
versatile beamscanning capabilities. The proposed concept and achieved
performance, computed using realistic material parameters, are extremely
promising for beamscanning at THz frequencies, and could pave the way to
graphene-based reconfigurable transceivers and sensors.Comment: 7 pages; 10 figure
College Athletics: The Chink in the Seventh Circuit\u27s Law and Economics Armor
If any court is linked to the âlaw and economicsâ movement, it is the Seventh Circuit, home of former Judge Richard Posner, the âChicago School,â and analysis based on markets and economics. It thus comes as a surprise that in college-athletics cases, the court has replaced economic analysis with legal formalisms. In adopting a deferential approach that would uphold nearly every rule the National Collegiate Athletic Association (NCAA) claims is related to amateurism, the court recalls the pre- Chicago School era, in which courts aggressively applied âper seâ illegality based on a restraintâs form, rather than substance. While the Seventh Circuitâs detour of deference has taken several stops, this Essay focuses on the most recent, the 2018 decision in Deppe v. NCAA
Heparin - Messias or Verschlimmbesserung?
A heightened risk of thrombosis noted early on with the severe acute respiratory syndrome coronavirus 2 infection led to the widespread use of heparin anticoagulation in the coronavirus disease 2019 (COVID-19) pandemic. However, reports soon started appearing in the literature where an apparent failure of heparin to prevent thrombotic events was observed in hospitalized patients with this viral infection. In this review, we explore the likely mechanisms for heparin failure with particular relevance to COVID-19. We also explore the role of anti-Xa assays and global hemostatic tests in this context. The current controversy of dosing heparin in this disease is detailed with some possible mechanistic reasons for anticoagulant failure. We hope that lessons learnt from the use of heparin in COVID-19 could assist us in the appropriate use of this anticoagulant in the future
Optimisation de la culture de microalgues pour la production de biodiésel
Affiche prĂ©sentĂ©e dans le cadre du colloque de l'ARC "La gestion de la propriĂ©tĂ© intellectuelle : courants de pensĂ©e et facteurs de succĂšs", lors du 81e CongrĂšs de l'Acfas Ă l'UniversitĂ© Laval, le 8 mai 2013.Le troisiĂšme prix a Ă©tĂ© dĂ©cernĂ© Ă Marc-Olivier BĂ©liveau, Virginie Bertrand-Lehouillier, Jessica Carrier et Joannie Tremblay au concours des Prix Ă©tudiants 2012-2013 de l'ARC.Dans lâoptique de production de biodiĂ©sel, notre projet consistait Ă Ă©valuer des conditions de culture de microalgues influençant la croissance et la production lipidique. Les souches Chlorella vulgaris, Scenedesmus sp. et Pseudokirchneriella subcapitata ont Ă©tĂ© cultivĂ©es dans diffĂ©rents milieux, dont des eaux usĂ©es, en version immobilisĂ©e tout comme en suspension. En plus dâavoir comparĂ© les biomasses obtenues, des analyses en contenu lipidique des cultures ont Ă©tĂ© rĂ©alisĂ©es par coloration in situ et quantification par fluorescence
Value-Compressed Sparse Column (VCSC): Sparse Matrix Storage for Redundant Data
Compressed Sparse Column (CSC) and Coordinate (COO) are popular compression
formats for sparse matrices. However, both CSC and COO are general purpose and
cannot take advantage of any of the properties of the data other than sparsity,
such as data redundancy. Highly redundant sparse data is common in many machine
learning applications, such as genomics, and is often too large for in-core
computation using conventional sparse storage formats. In this paper, we
present two extensions to CSC: (1) Value-Compressed Sparse Column (VCSC) and
(2) Index- and Value-Compressed Sparse Column (IVCSC). VCSC takes advantage of
high redundancy within a column to further compress data up to 3-fold over COO
and 2.25-fold over CSC, without significant negative impact to performance
characteristics. IVCSC extends VCSC by compressing index arrays through delta
encoding and byte-packing, achieving a 10-fold decrease in memory usage over
COO and 7.5-fold decrease over CSC. Our benchmarks on simulated and real data
show that VCSC and IVCSC can be read in compressed form with little added
computational cost. These two novel compression formats offer a broadly useful
solution to encoding and reading redundant sparse data
Northern Ghana hydrogeological assessment project
Groundwater is the most viable source of potable water in northern Ghana, West Africa, especially for the
80% rural inhabitants. Millions of dollars have been expended there on groundwater-based water supply
infrastructures, and these expenditures are likely to continue in coming decades. The Hydrogeological Assessment
Project (HAP) of the Northern Regions of Ghana was initiated to provide scientific background for
groundwater-based supply projects as well as resource management. This paper summarizes the technical
approaches and results to date, which include a compilation of available data, targeted field data collection,
and the development of a regional hydrogeological synthesis
Anticoagulation of cancer patients with nonĂą valvular atrial fibrillation receiving chemotherapy: Guidance from the SSC of the ISTH
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150593/1/jth14478.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150593/2/jth14478_am.pd
Anticoagulation in splanchnic and cerebral vein thrombosis : an international vignette-based survey
Background: Anticoagulant treatment of splanchnic (SVT) and cerebral vein thrombosis (CVT) can be challenging due to the rarity of these conditions, the concomitantly high thrombotic and bleeding risks, and the available low-quality evidence.
Objectives: To explore the current therapeutic approaches to SVT and CVT, and the rationale behind the anticoagulant treatment choice.
Methods: A cross-sectional survey was conducted (October 2018-April 2019) among members of three thrombosis and hemostasis societies. The survey consisted of four vignette cases: (i) SVT secondary to transient risk factor; (ii) cirrhotic SVT with esophageal varices; (iii) CVT secondary to transient risk factor; and (iv) unprovoked CVT with intracranial hemorrhage.
Results: A total of 397 physicians responded to the survey. There was wide variability in anticoagulant treatment options, starting time, and duration. Vitamin K antagonists were the commonest choice across the four vignette cases (44.2%-63.0%). The direct oral anticoagulants (DOACs) were the second commonest choice in low-bleeding-risk scenarios (27.7% in case 1, 22.9% in case 3), while parenteral anticoagulation alone was the second commonest choice in high-bleeding-risk scenarios (39.9% in case 2, 39.8% in case 4). The most frequent reasons for selecting DOACs were oral route of administration (50.6%), lack of need for laboratory monitoring (48.1%), and favorable safety profile of these drugs (43.4%).
Conclusions: The results of our study showed that, despite being off-label, the DOACs were considered for the treatment of unusual-site venous thromboembolism. The wide variability among different physicians reflected the clinical difficulties and raised the need for more collaborative trials on these disorders.peer-reviewe
A survey of thrombosis experts evaluating practices and opinions regarding venous thromboprophylaxis in patients post major abdominal surgery
EEG functional connectivity prior to sleepwalking : evidence of interplay between sleep and wakefulness
Study Objectives: Although sleepwalking (somnambulism) affects up to 4% of adults, its pathophysiology remains poorly understood. Sleepwalking can be
preceded by fluctuations in slow-wave sleep EEG signals, but the significance of these pre-episode changes remains unknown and methods based on EEG
functional connectivity have yet to be used to better comprehend the disorder.
Methods: We investigated the sleep EEG of 27 adult sleepwalkers (mean age: 29 ± 7.6 years) who experienced a somnambulistic episode during slow-wave
sleep. The 20-second segment of sleep EEG immediately preceding each patientâs episode was compared with the 20-second segment occurring 2 minutes
prior to episode onset.
Results: Results from spectral analyses revealed increased delta and theta spectral power in the 20 seconds preceding the episodesâ onset as compared to
the 20 seconds occurring 2 minutes before the episodes. The imaginary part of the coherence immediately prior to episode onset revealed (1) decreased delta
EEG functional connectivity in parietal and occipital regions, (2) increased alpha connectivity over a fronto-parietal network, and (3) increased beta connectivity
involving symmetric inter-hemispheric networks implicating frontotemporal, parietal and occipital areas.
Conclusions: Taken together, these modifications in EEG functional connectivity suggest that somnambulistic episodes are preceded by brain processes
characterized by the co-existence of arousal and deep slee
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