348 research outputs found
Distribution quantique de clés avec des photomultiplicateurs digitaux à base de silicium
Les ordinateurs quantiques sont une technologie prometteuse qui pourrait permettre de
faire des calculs qui sont impossibles pour les ordinateurs modernes dans un temps raison-
nable. Dâautre part, les techniques cryptographiques modernes se basent sur des problĂšmes
computationnels difficiles pour assurer leur sĂ©curitĂ©. Ainsi, lâarrivĂ©e des ordinateurs quan-
tiques pourrait sévÚrement compromettre la sécurité des techniques courantes. La distri-
bution quantique de clés (QKD en anglais) est une façon de distribuer des clés de cryptage
secrĂštes qui utilise des propriĂ©tĂ©s quantiques. Ceci fait en sorte quâun malfaiteur (mĂȘme
avec un ordinateur quantique) ne pourrait pas essayer dâintercepter le message sans courir
la chance dâinduire des erreurs dans le message. En QKD, lâinformation (les qubits) est
transmise via des fibres optiques ou lâair libre, mais la distance et la vitesse de transmission
est limitée en ce moment. Le but de ce projet est de faire un circuit intégré qui servirait
de détecteur pour un receveur QKD. Il utilisera des PDC (Photon-to-Digital Converter)
et lâĂ©lectronique rapide de 65 nm TSMC afin de livrer un receveur Ă haut dĂ©bit. Lâavan-
tage dâun PDC est quâil offre la possibilitĂ© dâadapter le dĂ©tecteur pour lâapplication. Dans
ce cas, du traitement de donnĂ©es et un circuit de fenĂȘtrage ont Ă©tĂ© ajoutĂ©s pour rendre
le receveur plus efficace. Le PDC contient aussi des TDC (time-to-digital converter) qui
mesurent le temps dâarrivĂ©e des photons dĂ©tectĂ©s. Parmi mes contributions originales, jâai
dĂ©veloppĂ©, implĂ©mentĂ© et validĂ© un circuit de fenĂȘtrage pour les TDC ainsi quâun circuit
de catĂ©gorisation pour le QKD. Dans ce mĂ©moire et dans lâarticle publiĂ© (chapitre 7), je
prĂ©sente ces contributions et je dĂ©montre ainsi que les PDC peuvent ĂȘtre des receveurs
QKD qui offrent une excellente performance temporelle (22.7 ps gigue temporelle) qui est
trĂšs attrayante pour le QKD. Le but du projet Ă©tait de dĂ©montrer lâavantage des PDC et
la tùche a été accomplie. Toutefois, il y a certains éléments qui pourraient améliorer les
performances du systÚme. Par exemple, les senseurs monophotonique utilisés étaient des
SPAD (Single Photon Avalanche Diode) temporaires afin dâavoir un signal rĂ©aliste pour
lâĂ©lectronique. Dans les itĂ©rations futures, et avec lâavancement dâautres projets au sein du
groupe de recherche GRAMS, des SPAD optimisĂ©s pourraient ĂȘtre utilisĂ©s afin dâamĂ©liorer
la sensibilitĂ© Ă la lumiĂšre et rĂ©duire de bruit dâobscuritĂ© du systĂšme. De plus, des efforts
devraient ĂȘtre mis sur lâuniformisation des performances des composantes au travers de la
matrice de pixel du PDC. Des travaux sur des meilleurs formes de calibration des pixels
sont en cours
Early multifocal stenosis after coronary artery snaring during off-pump coronary artery bypass in a patient with diabetes
AbstractJ Thorac Cardiovasc Surg 2001;122:1044-
Business as usual? Cannabis legalisation and agrarian change in Zimbabwe
This article examines the emerging legal cannabis sector in Zimbabwe since 2018, which focuses on medicinal and industrial cannabis with unlicenced uses remaining criminalised, as well as its implications for agrarian change. It shows that the formal sector is set up in a way that prioritises those with substantial resources â marginalising small-scale farmers and illicit cultivators. While this presents the risk of corporate capture, various factors combine to undermine agribusiness' production. However, prohibition of recreational cannabis and the formal sectorâs focus on export markets combine to preserve illicit cannabis markets and allow continuation of illicit livelihoods
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
Focused Review on Transthoracic Echocardiographic Assessment of Patients with Continuous Axial Left Ventricular Assist Devices
Left ventricular assist devices (LVADs) are systems for mechanical support for patients with end-stage heart failure. Preoperative, postoperative and comprehensive followup with transthoracic echocardiography has a major role in LVAD patient management. In this paper, we will present briefly the hemodynamics of axial-flow LVAD, the rationale, and available data for a complete and organized echocardiographic assessment in these patients including preoperative assessment, postoperative and long-term evaluation
Solar-like oscillations in the G2 subgiant beta Hydri from dual-site observations
We have observed oscillations in the nearby G2 subgiant star beta Hyi using
high-precision velocity observations obtained over more than a week with the
HARPS and UCLES spectrographs. The oscillation frequencies show a regular comb
structure, as expected for solar-like oscillations, but with several l=1 modes
being strongly affected by avoided crossings. The data, combined with those we
obtained five years earlier, allow us to identify 28 oscillation modes. By
scaling the large frequency separation from the Sun, we measure the mean
density of beta Hyi to an accuracy of 0.6%. The amplitudes of the oscillations
are about 2.5 times solar and the mode lifetime is 2.3 d. A detailed comparison
of the mixed l=1 modes with theoretical models should allow a precise estimate
of the age of the star.Comment: 13 pages, 14 figures, accepted by ApJ. Fixed minor typo (ref to Fig
14
S100A4 as a Target of the E3-Ligase Asb2ÎČ and Its Effect on Engineered Heart Tissue
Background: S100A4 has recently emerged as an important player in cardiac disease, affecting phenotype development in animal models of myocardial infarction and pathological cardiac hypertrophy, albeit it is unclear whether S100A4 exerts a detrimental or beneficial function. The goal of the current study was to analyze S100A4 expression in models of cardiac pathology, investigate its degradation by the ubiquitin-proteasome system (UPS), and furthermore examine the functional effects of S100A4 levels in a 3D model of engineered heart tissue (EHT).Methods and Results: S100A4 mRNA and protein levels were analyzed in different models of cardiac pathology via quantitative RT-PCR and Western blot, showing a higher S100A4 steady-state protein concentration in hearts of Mybpc3-knock-in (KI) hypertrophic cardiomyopathy (HCM) mice. COS-7 cells co-transfected with plasmids encoding mutant (MUT) Asb2ÎČ lacking the E3 ligase activity in combination with V5-tagged S100A4 plasmid presented higher S100A4-V5 protein steady-state concentrations than cells co-transfected with the Asb2ÎČ wild type (WT) plasmid. This effect was blunted by treatment with the specific proteasome inhibitor epoxomicin. Adeno-associated virus serotype 6 (AAV6)-mediated S100A4 overexpression in a 3D model of EHT did not affect contractile parameters. Immunofluorescence analysis showed a cytosolic and partly nuclear expression pattern of S100A4. Gene expression analysis in EHTs overexpressing S100A4-V5 showed markedly lower steady-state concentrations of genes involved in cardiac fibrosis and pathological cardiac hypertrophy.Conclusion: We showed that S100A4 protein level is higher in cardiac tissue of Mybpc3-KI HCM mice probably as a result of a lower degradation by the E3 ligase Asb2ÎČ. While an overexpression of S100A4 did not alter contractile parameters in EHTs, downstream gene expression analysis points toward modulation of signaling cascades involved in fibrosis and hypertrophy
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