5,133 research outputs found
Unusual magneto-transport of YBa2Cu3O7-d films due to the interplay of anisotropy, random disorder and nanoscale periodic pinning
We study the general problem of a manifold of interacting elastic lines whose
spatial correlations are strongly affected by the competition between random
and ordered pinning. This is done through magneto-transport experiments with
YBa2Cu3O7-d thin films that contain a periodic vortex pinning array created via
masked ion irradiation, in addition to the native random pinning. The strong
field-matching effects we observe suggest the prevalence of periodic pinning,
and indicate that at the matching field each vortex line is bound to an
artificial pinning site. However, the vortex-glass transition dimensionality,
quasi-2D instead of the usual 3D, evidences reduced vortex-glass correlations
along the vortex line. This is also supported by an unusual angular dependence
of the magneto-resistance, which greatly differs from that of Bose-glass
systems. A quantitative analysis of the angular magnetoresistance allows us to
link this behaviour to the enhancement of the system anisotropy, a collateral
effect of the ion irradiation
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Lipotoxicity: a driver of heart failure with preserved ejection fraction?
Heart failure with preserved ejection fraction (HFpEF) is a growing public health concern, with rising incidence alongside high morbidity and mortality. However, the pathophysiology of HFpEF is not yet fully understood. The association between HFpEF and the metabolic syndrome (MetS) suggests that dysregulated lipid metabolism could drive diastolic dysfunction and subsequent HFpEF. Herein we summarise recent advances regarding the pathogenesis of HFpEF in the context of MetS, with a focus on impaired lipid handling, myocardial lipid accumulation and subsequent lipotoxicity.We thank the British Heart Foundation [grant numbers RG/18/7/33636 and FS/17/61/33473]; the Cambridge BHF Centre of Research Excellence [grant number RE/18/1/34212]; and the Medical Research Council [grant number MC UU 12012/2] for funding this work
A Nonperturbative Eliasson's Reducibility Theorem
This paper is concerned with discrete, one-dimensional Schr\"odinger
operators with real analytic potentials and one Diophantine frequency. Using
localization and duality we show that almost every point in the spectrum admits
a quasi-periodic Bloch wave if the potential is smaller than a certain constant
which does not depend on the precise Diophantine conditions. The associated
first-order system, a quasi-periodic skew-product, is shown to be reducible for
almost all values of the energy. This is a partial nonperturbative
generalization of a reducibility theorem by Eliasson. We also extend
nonperturbatively the genericity of Cantor spectrum for these Schr\"odinger
operators. Finally we prove that in our setting, Cantor spectrum implies the
existence of a -set of energies whose Schr\"odinger cocycle is not
reducible to constant coefficients
Descent of Equivalences and Character Bijections
Categorical equivalences between block algebras of finite groupsâsuch as Morita and derived equivalencesâare well known to induce character bijections which commute with the Galois groups of field extensions. This is the motivation for attempting to realise known Morita and derived equivalences over non-splitting fields. This article presents various results on the theme of descent to appropriate subfields and subrings. We start with the observation that perfect isometries induced by a virtual Morita equivalence induce isomorphisms of centres in non-split situations and explain connections with Navarroâs generalisation of the AlperinâMcKay conjecture. We show that Rouquierâs splendid Rickard complex for blocks with cyclic defect groups descends to the non-split case. We also prove a descent theorem for Morita equivalences with endopermutation source
Homogénéisation des signaux isotopiques, 18O et 3H, dans un systÚme hydrologique de haute montagne : la Vallée d'Aoste (Italie)
L'analyse de l'origine et de la dynamique des Ă©coulements souterrains dans l'aquifĂšre du milieu alluvial de la plaine d'Aoste (Italie) a Ă©tĂ© menĂ©e en Ă©tudiant les teneurs isotopiques (18O et 3H) des eaux sur l'ensemble du systĂšme hydrologique. La dĂ©marche a consistĂ© en un suivi isotopique des prĂ©cipitations pluvio-neigeuses, des sources de versants, du rĂ©seau de surface et de l'aquifĂšre alluvial, complĂ©tĂ© par des analyses ponctuelles concernant l'horizon superficiel des glaciers et les sous-Ă©coulements glaciaires. Le signal d'entrĂ©e en 18O portĂ© par les prĂ©cipitations prĂ©sente une grande variabilitĂ© liĂ©e au contexte orographique (effet d'Ă©cran) et climatique (pluie ou neige). Celle-ci est mise en Ă©vidence par les changements saisonniers du gradient 18O/altitude. En moyenne annuelle (1994), ce gradient Ă©tabli en VallĂ©e d'Aoste Ă partir de mesures sur les prĂ©cipitations rĂ©coltĂ©es entre 300 et 3500 m d'altitude (sur huit stations) est de - 0.18 ± 0.02 â° pour 100 m, avec un Ă©cart-type (s) des valeurs de ± 4,8 â°. L'ensemble des rĂ©sultats en 18O montre au cours du cycle hydrologique, un amortissement Ă la fois important et progressif du signal d'entrĂ©e fourni par les prĂ©cipitations. Cet amortissement, de l'ordre de 30 fois dans l'aquifĂšre alluvial (sigma=± 0.15 â°), est particuliĂšrement sensible au niveau de la glace et des sous-Ă©coulements glaciaires. En ce qui concerne les rĂ©sultats en 3H, les teneurs mesurĂ©es dans les prĂ©cipitations se rĂ©vĂšlent ĂȘtre Ă©troitement liĂ©es avec l'origine et la trajectoire des masses d'air humide. Par ailleurs, on note une bonne concordance entre les temps de sĂ©jour des eaux dans l'aquifĂšre alluvial calculĂ©s Ă partir des valeurs en 18O et ceux fournis par le 3H.The hydrogeological study of the alluvial aquifer of the Aosta plain (Italy) is chosen as one of the most appropriate examples representative of the Italian-French-Swiss Alps. This study has been carried out using two environmental isotopes (18O and 3H) for groundwater samples taken from this aquifer in order to shed light on the origin of water and the hydrodynamic characteristics of the aquifer.The surface area of this aquifer is 70 km_ and mean elevation ranges between 400 and 700 m (asl). This surface area constitutes a part of the watershed area that amounts 2400 km_ with a mean elevation of 2200 m (asl). The watershed possesses several mountain peaks, Mt. Blanc, Mt. Cervin, Mt. Grand Paradis, the elevation of which rise to over 4000 m.The input signal, quantitative and qualitative as well, provided by the precipitation shows a wide variability linked to both orographic (screen effect) and climatic (rain or snow) influences. This variability is marked by differences in the 18O/altitude gradient, which is seasonally dependent. A unique and linear relation is observed during spring and summer ; in autumn and winter results show an important gradient up to 2000 m but a less important one for higher altitudes.The mean annual (1994) gradient of - 0.18 ± 0.02 â° for 100 m is determined in Aosta valley for altitudes between 300 and 3500 m, and the standard deviation (sigma) of the mean volume-weighted value for precipitation is ± 4.8 â°. Furthermore, the 18O values measured in the alluvial aquifer have shown a very low dispersion (sigma=± 0.15 â°), which corresponds to a buffering effect of a factor 30. These results evidenced, thus, an homogenization process within the different water bodies.To analyze this homogenization process, the different components of the hydrologic system have been studied, i.e. the monitoring of the springs and runoff waters, with complementary local measurements of the upper part of ice cores and the glacier underflows. Using standard deviations (sigma) as criteria for the homogenization process, one can see a large and progressive decrease along the hydrological cycle, with a special amplitude in ice cores and glacier underflows : precipitation (± 4.8 â°), ice core (± 0.8 â°), glacier underflow (± 0.10 â°), spring (± 0.15 â°), surface runoff network (± 0.3 â°), alluvial aquifer (± 0.15 â°).In ice cores, the different process : freezing and thawing, compression, and vapor / liquid / solid exchanges have caused the 18O homogenization. Dealing with the springs on the slopes of the valley, the preferential flow paths linked to the fracturation lead to a mixing of waters and hence to a very buffered outflow signal. The combined effect of all these explains the stability and the uniformity of the data found in the alluvial water body.As far as the 3H concentrations are concerned, the values measured are tightly linked with the origin and the transport of humid air masses. For closely spaced stations, a significant difference in the input signal has been correlated to various climatic influences. Using 3H data from the Thonon-les-Bains station (included in the WMO-IAEA observation network) as input, the calculated transit times of 2.5 to 7.5 years are very close to those calculated with 18O, i.e. 4 to 7 years
Preparation and Loading with Rifampicin of Sub-50ânm Poly(ethyl cyanoacrylate) Nanoparticles by Semicontinuous Heterophase Polymerization
We report the preparation of poly(ethyl cyanoacrylate) (PECA) nanoparticles by semicontinuous heterophase polymerization carried out at monomer starved conditions at three monomer addition rates. Particles in the nanometer range were obtained, the size of which diminishes with decreasing monomer addition rate as shown by the fact that particles with mean diameters of ca. 42 and 30ânm were obtained at the faster and intermediate dosing rates, respectively, whereas two populations of particles, one of 15.5 and the other of 36ânm in mean diameters, were produced at the slower dosing rate. The obtained molecular weights were from 2,200 to 3,500âg/mol, depending on the addition rate, which are typical of the anionic polymerizations of cyanoacrylates in aqueous dispersions at low pHs. The rifampicin (RIF) loading into the nanoparticles was successful since the entire drug added was incorporated. The drug release study carried out at pH of 7.2 indicated a faster release from the free RIF at intermediate and larger release times as expected since, in the nanoparticles, first the drug has to diffuse through the nanoparticle structure. The comparison of several drug release models indicates that the RIF release from PECA nanoparticles follows that of Higuchi
Correction: Porous monoliths synthesized via polymerization of styrene and divinyl benzene in nonaqueous deep-eutectic solvent-based HIPEs (RSC Advances (2015) 5 (23255-23260) DOI: 10.1039/C5RA02374B)
© 2018 The Royal Society of Chemistry. The authors regret that there was an error in the results and discussion section of the original article. On page 23257, the text read, The surfactant employed here was sorbitan monooleate . This should have read, The surfactant employed here was sorbitan stearate . The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers
Eliashberg-type equations for correlated superconductors
The derivation of the Eliashberg -- type equations for a superconductor with
strong correlations and electron--phonon interaction has been presented. The
proper account of short range Coulomb interactions results in a strongly
anisotropic equations. Possible symmetries of the order parameter include s, p
and d wave. We found the carrier concentration dependence of the coupling
constants corresponding to these symmetries. At low hole doping the d-wave
component is the largest one.Comment: RevTeX, 18 pages, 5 ps figures added at the end of source file, to be
published in Phys.Rev. B, contact: [email protected]
Abnormal quality detection and isolation in water distribution networks using simulation models
This paper proposes a model based detection and localisation method to deal with abnormal quality levels based on the chlorine measurements and chlorine sensitivity analysis in a water distribution network. A fault isolation algorithm which correlates on line the residuals (generated by comparing the available chlorine measurements with their estimations using a model) with the fault sensitivity matrix is used. The proposed methodology has been applied to a District Metered Area (DMA) in the Barcelona network
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