Arable weeds in alley cropping agroforestry systems - results of a first year survey

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Disentangling the conductivity spectra of two-dimensional organic conductors

The optical spectrum of a κ -phase organic conductor is thoroughly analyzed for the example of κ -(BEDT-TTF) 2 Cu [ N(CN) 2 ] Br 0.85 Cl 0.15 in order to identify its various contributions. It is shown how the complex spectra can be decomposed using different approaches; the intradimer and interdimer contributions are discussed. In particular the fingerprints of electronic correlations in these spectra are considered

Phase diagram of quarter-filled band organic salts, [EDT-TTF-CONMe2]2X, X = AsF6 and Br

An investigation of the P/T phase diagram of the quarter-filled organic conductors, [EDT-TTF-CONMe2]2X, is reported on the basis of transport and NMR studies of two members, X=AsF6 and Br of the family. The strongly insulating character of these materials in the low pressure regime has been attributed to a remarkably stable charge ordered state confirmed by 13C NMR and the only existence of 1/4 Umklapp e-e scattering favoring a charge ordering instead of the 1D Mott localization seen in (TM)2X which are quarter-filled compounds with dimerization. A non magnetic insulating phase instead of the spin density wave state is stabilized in the deconfined regime of the phase diagram. This sequence of phases observed under pressure may be considered as a generic behavior for 1/4-filled conductors with correlations

Charge-transfer processes in radical ion molecular conductors κ-(BEDT-TTF)2Cu[N(CN)2]Br x Cl1 − x : The superconductor (x = 0.9) and the conductor with the metal-insulator transition (x = 0)

Optical spectral investigations of low-dimensional organic molecular conductors κ-(BEDT-TTF)2Cu[N(CN)2]Br x Cl1 − x with x = 0.9 (the superconductor with T c = 11.3 K) and x = 0 (the metal with the metal-insulator transition at T < 50 K) are performed in the range 50–6000 cm−1 (6 meV–0.74 eV) at temperatures from 300 to 20 K. The optical conductivity spectra are quantitatively analyzed in terms of the proposed model, according to which the charge transfer involves two types of charge carriers, i.e., electrons (holes) localized on clusters (dimers and tetramers formed by BEDT-TTF molecules) and quasi-free charge carriers, with the use of the tetramer “cluster“ model based on the Hubbard Hamiltonian for correlated electrons and the Drude model for quasi-free charge carriers. Physical parameters of the model, such as the energy of Coulomb repulsion between two electrons (holes) in one molecule, the transfer integrals between molecules inside the dimer and between dimers, and the electron-molecular vibration coupling constants, are determined. The anisotropy of the spectra in the conducting plane is explained. The inference is made that only electrons localized on clusters couple with intramolecular vibrations

Mott transition and transport crossovers in the organic compound κ−(BEDT−TTF)2Cu[N(CN)2]Cl\kappa-(BEDT-TTF)_2 Cu[N(CN)_2] Cl

We have performed in-plane transport measurements on the two-dimensional organic salt $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Cl. A variable (gas) pressure technique allows for a detailed study of the changes in conductivity through the insulator-to-metal transition. We identify four different transport regimes as a function of pressure and temperature (corresponding to insulating, semi-conducting, ''bad metal'', and strongly correlated Fermi liquid behaviours). Marked hysteresis is found in the transition region, which displays complex physics that we attribute to strong spatial inhomogeneities. Away from the critical region, good agreement is found with a dynamical mean-field calculation of transport properties using the numerical renormalization group technique.Comment: 4 pages, 6 figure

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

Dissociable effects of prediction and integration during language comprehension: Evidence from a large-scale study using brain potentials

Composing sentence meaning is easier for predictable words than for unpredictable words. Are predictable words genuinely predicted, or simply more plausible and therefore easier to integrate with sentence context? We addressed this persistent and fundamental question using data from a recent, large-scale (N = 334) replication study, by investigating the effects of word predictability and sentence plausibility on the N400, the brain's electrophysiological index of semantic processing. A spatiotemporally fine-grained mixed-effects multiple regression analysis revealed overlapping effects of predictability and plausibility on the N400, albeit with distinct spatiotemporal profiles. Our results challenge the view that the predictability-dependent N400 reflects the effects of either prediction or integration, and suggest that semantic facilitation of predictable words arises from a cascade of processes that activate and integrate word meaning with context into a sentence-level meaning

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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Does chronic lung inflammation induce an increase in tryptophan catabolism through IDO (indoleamine 2,3-dioxygenase) pathway in pigs ?

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