Evidence for the coexistence of Dirac and massive carriers in a-(BEDT-TTF)2I3 under hydrostatic pressure

Transport measurements were performed on the organic layered compound \aI3 under hydrostatic pressure. The carrier types, densities and mobilities are determined from the magneto-conductance of \aI3 . While evidence of high-mobility massless Dirac carriers has already been given, we report here, their coexistence with low-mobility massive holes. This coexistence seems robust as it has been found up to the highest studied pressure. Our results are in agreement with recent DFT calculations of the band structure of this system under hydrostatic pressure. A comparison with graphene Dirac carriers has also been done.Comment: 5 pages 5 figure

Radical cation salts of TTF donors with XF6 (X = Re,Ta) anions

Electrocrystallization of the dianionic Re(IV)F6 species with different organic π electron donors was carried out. Depending on the first oxidation potential of the TTF derivatives this crystallization technique gave rise to various radical cations salts involving Re(IV) or Re(V) anions. With tetramethyltetrathiafulvalene (TMTTF) the (TMTTF)2Re(IV)F6  salt was obtained. However, with tetramethyltetraselenafulvalene (TMTSF) we obtained very small needles of the (TMTSeF)2Re(V)F6 system, analogue to the so called “Bechgaard salts” [1]. We present some characteristics of this new metallic phase. We compare to the diamagnetic (TMTSeF)2Ta(V)F6 obtained by the same strategy using TBATaF6 prepared according to the Browstein’s method [2] and explore electrocrystallization of the tantalum based anions [3], [4]. References: [1] K. Bechgaard, C.S. Jacobsen, K. Mortensen, H.J. Pedersen, N. Thorup, Solid State Commun. 1980, 33, 1119-1125. [2] S. Brownstein, Inorg. Chem. 1973, 12, N°3, 584-589. [3] C. Lenoir, K. Boubekeur, P. Batail, E. Canadell, P. Auban, O. Traetteberg, D. Jérome, Synth. Met. 1991, 42, 1939-1942. [4] F. Iwase, K. Sugiura, K. Furukawa, T. Nakamura, J. Phys. Soc. Jpn. 2009, 78, N°10, 104717:1-104717:7

Crystal structure of tetrametyltetrathiafulvalenium (1S)-camphor-10-sulfonate dihydrate

Electro-oxidation of tetra­methyl­tetra­thia­fulvalene (TMTTF) in the presence of the chiral anion (1S)-camphor-10-sulfonate (S-camphSO3-) in tetra­hydro­furan/water medium afforded a 1/1 salt formulated as TMTTF·S-camphSO3·2H2O or 2-(4,5-dimethyl-1,3-di­thiol-2-yl­idene)-4,5-dimethyl-1,3-di­thiole radical ion (1+) [(1S)-7,7-dimethyl-2-oxobi­cyclo­[2.2.1]heptan-1-yl]methane­sulfonate dihydrate, C10H12S4+·C10H15O4S-·2H2O. In this salt, two independent TMTTF units are present but, in both cases, the observed bond lengths and especially the central C=C distance [1.392 (6) and 1.378 (6) Å] are in agreement with a complete oxidation of TMTTF which is thus present as TMTTF.+ radical cations. These cations form one-dimensional stacks in which they are associated two by two, forming dimers with short [3.472 (1) to 3.554 (2) Å] S...S contacts. The two S-camphSO3 anions present also form stacks and are connected with each other via the water mol­ecules with many O-H...O hydrogen bonds ranging from 1.86 (3) to 2.15 (4) Å; the O-H...O hydrogen-bonding network can be described as being constituted of C22(6) chains bearing R33(11) lateral rings. On the other hand, the columns of cations and anions are connected through C-H...O hydrogen bonds, forming a system expanding in three directions; finally, the result is a three-dimensional network of O-H...O and C-H...O hydrogen bonds

Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers

In the two-dimensional organic charge-transfer salts kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x} a systematic variation of the Br content from x = 0 to 0.9 allows us to tune the Mott transition by increasing the bandwidth. At temperatures below 50 K, an energy gap develops in the Cl-rich samples and grows to approximately 1000 cm-1 for T -> 0. With increasing Br concentration spectral weight shifts into the gap region and eventually fills it up completely. As the samples with x = 0.73, 0.85 and 0.9 become metallic at low temperatures, a Drude-like response develops due to the coherent quasiparticles. Here, the quasiparticle scattering rate shows a omega^2 dependence and the effective mass of the carriers is enhanced in agreement with the predictions for a Fermi liquid. These typical signatures of strong electron-electron interactions are more pronounced for compositions close to the critical value x_c \approx 0.7 where the metal-to-insulator transition occurs.Comment: 11 pages, 12 figure

Limits on prediction in language comprehension: A multi-lab failure to replicate evidence for probabilistic pre-activation of phonology

In current theories of language comprehension, people routinely and implicitly predict upcoming words by pre-activating their meaning, morpho-syntactic features and even their specific phonological form. To date the strongest evidence for this latter form of linguistic prediction comes from a 2005 Nature Neuroscience landmark publication by DeLong, Urbach and Kutas, who observed a graded modulation of article- and noun-elicited electrical brain potentials (N400) by the pre-determined probability that people continue a sentence fragment with that word ('cloze'). In a direct replication study spanning 9 laboratories (N=334), we failed to replicate the crucial article-elicited N400 modulation by cloze, while we successfully replicated the commonly-reported noun-elicited N400 modulation. This pattern of failure and success was observed in a pre-registered replication analysis, a pre-registered single-trial analysis, and in exploratory Bayesian analyses. Our findings do not support a strong prediction view in which people routinely pre-activate the phonological form of upcoming words, and suggest a more limited role for prediction during language comprehension

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Agroforestries: a new mixed technological network for agroforestry development in France

PosterFacing new challenges of agriculture, the research for more sustainable agrosystems includes a growing interest in agroforestry practices. Over the past years, a large number of experimental and demonstration plots have been established all around France. However, coordination between research and extension partners is lacking. In order to support innovations in agriculture, the French government encourages partnership between research, development and education stakeholders, through the creation of Mixed Technological Networks (Réseaux Mixtes Technologiques, RMT). These RMTs benefit from national recognition and receive a grant for network coordination and communication. In 2014, a new network was created: the RMT “AgroforesterieS” brings together about fifty members involved in agroforestry, from research, semi-public and associative farmers’ organizations, technical institutes, engineering offices, and agricultural schools. By sharing expertise, databases and demonstration sites, the network aims at (i) promoting collective dynamics for the development of sustainable and innovative agroforestry systems adapted to the French territorial constraints, and (ii) developing technical and methodological tools for the setting up and management of agroforestry systems. It will particularly achieve these by: 1. Creating an observatory of agroforestry practices, including both experimental and commercial sites, in order to provide technical references for farmers; 2. Carrying out a multicriteria assessment of agroforestry systems, in terms of economical, technical, agronomical and environmental performances, as well as adoption factors; 3. Ensuring the coordination of scientific and technical stakeholders in order to initiate new collectively-thought projects of research and development in agroforestry; 4. Developing and/or improve decision support tools for farmers and land managers for the design and management of agroforestry systems; 5. Drawing up a strategy for knowledge diffusion towards future advisors, learners, and users

Experimental observation of ultrasound fast and slow waves through three-dimensional printed trabecular bone phantoms.

International audienceIn this paper, ultrasound measurements of 1:1 scale three-dimensional (3D) printed trabecular bone phantoms are reported. The micro-structure of a trabecular horse bone sample was obtained via synchrotron x-ray microtomography, converted to a 3D binary data set, and successfully 3D-printed at scale 1:1. Ultrasound through-transmission experiments were also performed through a highly anisotropic version of this structure, obtained by elongating the digitized structure prior to 3D printing. As in real anisotropic trabecular bone, both the fast and slow waves were observed. This illustrates the potential of stereolithography and the relevance of such bone phantoms for the study of ultrasound propagation in bone

Pesticide-free agroforestry cropping system: re-conception and first evaluation of the global performances of the SCAOPEST

PresentationFrom mid 2000, in order to address global challenges, European member states’ strategies for agriculture have progressively identified and given priority to the set up of a multi-functional farm models. In France, to achieve both food security and socio-environmental sustainability, the design, test and deployment of new Productive and Efficient Cropping Systems (PECS) was then engaged. Therefore, those of the particular PECS targeting the re-conquest of water quality often work at reducing drastically, or even renouncing to chemical pesticides. For that, within the 2012 EXPE Dephy Ecophyto program, a 6-years SCA0PEST project (pesticide-free agroforestry cropping system) has been funded. Considering the experimental farm objectives and local sectors' potentials, SCA0PEST objectives are (i) the review of the current conventional agroforestry cropping system and its experts' opinions-based re-design by respecting principles of integrated pest & weed management, (ii) the set up of 6 over 8 of the crops of the crop rotation each year, (iii) the ex-ante and continuous economic, environmental and social assessments of its performances. Depending on raw products sale prices, energy and fertilizers costs, preliminary SCA0PEST ex-ante assessment provided limited economic prevision, as direct margin would decrease from 140 up to 250€/ha mainly due to yield losses and additional costs for seeds. Conversely, environmental performance would be improved as annual GHG emissions from the cultivated compartment fall down to 1140 kg eq.CO2/ha (48% of the reference cropping system with pesticides); additionally, when simulated, annualized carbon sequestration by trees should reach 650 kg eq.CO2/ha. Finally, inclusion of a 2-years alfalfa production within the rotation would provide a supplementary 230€/ha indirect gain when incorporated at 40% within the dairy cows ration. If this first SCA0PEST assessment points an acceptable economic balance and an improved environmental footprint, continuous assessments would have to confirm the potential of this innovative free-pesticide cropping system