771 research outputs found
Sublogarithmic uniform Boolean proof nets
Using a proofs-as-programs correspondence, Terui was able to compare two
models of parallel computation: Boolean circuits and proof nets for
multiplicative linear logic. Mogbil et. al. gave a logspace translation
allowing us to compare their computational power as uniform complexity classes.
This paper presents a novel translation in AC0 and focuses on a simpler
restricted notion of uniform Boolean proof nets. We can then encode
constant-depth circuits and compare complexity classes below logspace, which
were out of reach with the previous translations.Comment: In Proceedings DICE 2011, arXiv:1201.034
Enhancement of the magnetoelectric effect in multiferroic CoFeO/PZT bilayer by induced uniaxial magnetic anisotropy
In this study we have compared magnetic, magnetostrictive and piezomagnetic
properties of isotropic and anisotropic cobalt ferrite pellets. The isotropic
sample was prepared by the ceramic method while the sample exhibiting uniaxial
anisotropy was made by reactive sintering using Spark Plasma Sintering (SPS).
This technique permits to induce a magnetic anisotropy in cobalt ferrite in the
direction of the applied pressure during SPS process. Sample with uniaxial
anisotropy revealed a higher longitudinal magnetostriction and piezomagnetism
compared to the isotropic sample, but the transversal magnetostriction and
piezomagnetism were dramatically reduced. In the case of magnetoelectric
layered composite, the magnetoelectric coefficient is directly related to the
sum of the longitudinal and transversal piezomagnetic coefficients. These two
coefficients being opposite in sign, the use of material exhibiting high
longitudinal and low transversal piezomagnetic coefficient (or vice versa) in
ME devices is expected to improve the ME effect. Hence, ME bilayer devices were
made using isotropic and anisotropic cobalt ferrite stuck with a PZT layer. ME
measurements at low frequencies revealed that bilayer with anisotropic cobalt
ferrite exhibits a ME coefficient three times higher than a bilayer with
isotropic cobalt ferrite. We also investigated the behavior of such composites
when excited at resonant frequency
Vegetable oil hybrid films cross-linked at the air-water interface: formation kinetics and physical characterization
Vegetable oil based hybrid films were developed thanks to a novel solvent-
and heating- free method at the air-water interface using silylated castor oil
cross-linked via a sol-gel reaction. To understand the mechanism of the hybrid
film formation, the reaction kinetics was studied in detail by using
complementary techniques: rheology, thermogravimetric analysis, and infrared
spectroscopy. The mechanical properties of the final films were investigated by
nano-indentation, whereas their structure was studied using a combination of
wide-angle X-ray scattering, electron diffraction, and atomic force microscopy.
We found that solid and transparent films form in 24 hours and, by changing the
silica precursor to castor oil ratio, their mechanical properties are tunable
in the MPa-range by about a factor of twenty. In addition to that, a possible
optimization of the cross-linking reaction with different catalysts was
explored and finally, cytotoxicity tests were performed on fibroblasts proving
the absence of film toxicity. The results of this work pave the way to a
straightforward synthesis of castor-oil films with tunable mechanical
properties: hybrid films cross-linked at the air-water interface combine an
easy and cheap spreading protocol with the features of their thermal history
optimized for possible future micro/nano drug loading, thus representing
excellent candidates for the replacement of non-environment friendly
petroleum-based materials
Tunable double photochromism of a family of bis-DTE bipyridine ligands and their dipolar Zn complexes.
International audienceThe photoinduced ring-closure/ring-opening reactions of a series of bis-dithienylethene derivatives, as free ligands and Zn(II)-complexes, are investigated by resorting to theoretical (time-dependent density functional theory) and kinetic analyses in solution. The originality of the system stems from the tunability of the photoreaction quantum yields and conversion yields as a function of the electronic structure. The latter could be varied by modifying the electron-donating character of the DTE-end substituents L(a-d) (o,o) (a, D = H; b, D = OMe; c, D = NMe(2); d, D = NBu(2)) and/or the Lewis character of the metal ion center L(a-d)ZnX(2) (o,o) (L(a-c), X = OAc; L(d), X = Cl). The orbital description of the doubly-open form (o,o) and half-closed form (o,c) predicts that double closure to the form (c,c) would occur using UV irradiation. Photokinetic studies on the complete series demonstrate that photocyclization proceeds following a sequential ring closure mechanism. They clearly point out distinct quantum yields for the first and second ring closures, the latter being characterized by a significantly lower value. Dramatic decrease in both the quantum yields of the ring-closure and ring-opening processes is demonstrated for the complex L(d)ZnCl(2) exhibiting the strongest charge-transfer character in the series investigated. These studies show that this series of DTE derivatives provides an efficient strategy to tune the photochromic properties through the combination of the electron-donor and electron-acceptor (D-A) groups
Tricaesium tris(pyridine-2,6-dicarboxylato-κ3 O 2,N,O 6)lutetium(III) octahydrate
Colourless block crystals of the title compound, Cs3[Lu(dipic)3]·8H2O [dipic is dipicolinate or pyridine-2,6-dicarboxylate, C7H3NO4] were synthesized by slow evaporation of the solvent. The crystal structure of this LuIII-complex, isostructural with the DyIII and EuIII complexes, was determined from a crystal twinned by inversion and consists of discrete [Lu(dipic)3]3− anions, Cs+ cations and water molecules involving hydrogen bonding. The Lu atom lies on a twofold rotation axis and is coordinated by six O atoms and three N atoms of three dipicolinate ligands. One Cs atom is also on a twofold axis. The unit cell can be regarded as successive layers along the crystallographic c-axis formed by [Lu(dipic)3]3− anionic planes and [Cs+, H2O] cationic planes. In the crystal structure, although the H atoms attached to water molecules could not be located, short O—O contacts clearly indicate the occurrence of an intricate hydrogen-bonded network through contacts with other water molecules, Cs cations or with the O atoms of the dipicolinate ligands
Skills Alignment for Lifelong Learners in Higher Education: Smart Catalogues for Reskilling and Upskilling Pathways
The future of work and the ever-changing skills demand in the labour market has been a constant debate and pressing challenge for higher education institutions (HEI’s), governments and industry. In the current context, HEI’s must increase the transformational effect of education on people’s employability, on organizations’ competitiveness and on society’s progress. This paper presents the design and development of a mock-up career guidance tool to empower lifelong learners through digital reskilling and upskilling. We discuss the methods used for designing a skills alignment tool and a smart catalogue for identifying stackable training pathways in two specific disciplinary domains. The skills alignment methodology features a skill gap analysis (SGA) in the occupational domains of Data Science and Chemistry, linked to the evolution and demand of the European labour market through an ESCO compatible tool. The smart program catalog presents the necessary program information to facilitate the creation of stackable training pathways. Considerations are made for the importance of virtual career guidance tools for lifelong learners as we face the ever-changing demand of the labor market and as we continue to embrace online education, micro-credentialing and the digital transformation of higher education
A "reverse interrupter": the novel molecular design of a fluorescent photochromic DTE-based bipyridine
International audienceAn original design of a fluorescent dithienylethene (DTE)-based bipyridine, where donor (D) and acceptor (A) groups are located on the same thiophene ring of the DTE unit, is reported; in non-polar solvents, UV or visible excitation triggers a photochromic reaction, disrupting the conjugation and quenching the fluorescence
Translational Genomics in Legumes Allowed Placing In Silico 5460 Unigenes on the Pea Functional Map and Identified Candidate Genes in Pisum sativum L.
To identify genes involved in phenotypic traits, translational genomics from highly characterized model plants to poorly characterized crop plants provides a valuable source of markers to saturate a zone of interest as well as functionally characterized candidate genes. In this paper, an integrated view of the pea genetic map was developed. A series of gene markers were mapped and their best reciprocal homologs were identified on M. truncatula, L. japonicus, soybean, and poplar pseudomolecules. Based on the syntenic relationships uncovered between pea and M. truncatula, 5460 pea Unigenes were tentatively placed on the consensus map. A new bioinformatics tool, http://www.thelegumeportal.net/pea_mtr_translational_toolkit, was developed that allows, for any gene sequence, to search its putative position on the pea consensus map and hence to search for candidate genes among neighboring Unigenes. As an example, a promising candidate gene for the hypernodulation mutation nod3 in pea was proposed based on the map position of the likely homolog of Pub1, a M. truncatula gene involved in nodulation regulation. A broader view of pea genome evolution was obtained by revealing syntenic relationships between pea and sequenced genomes. Blocks of synteny were identified which gave new insights into the evolution of chromosome structure in Papillionoids and Eudicots. The power of the translational genomics approach was underlined
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