19,458 research outputs found
Dynamical photo-induced electronic properties of molecular junctions
Nanoscale molecular-electronic devices and machines are emerging as promising
functional elements, naturally flexible and efficient, for next generation
technologies. A deeper understanding of carrier dynamics in molecular junctions
is expected to benefit many fields of nanoelectronics and power-devices. We
determine time-resolved charge current flowing at donor- acceptor interface in
molecular junctions connected to metallic electrodes by means of quantum
transport simulations. The current is induced by the interaction of the donor
with a Gaussian-shape femtosecond laser pulse. Effects of the molecular
internal coupling, metal- molecule tunneling and light-donor coupling on
photocurrent are discussed. We then examine the junction working through the
time-resolved donor density of states. Non-equilibrium reorganization of
hybridized molecular orbitals through the light-donor interaction gives rise to
two phenomena: the dynamical Rabi shift and the appearance of Floquet-like
states. Such insights into the dynamical photoelectronic structure of molecules
are of strong interest for ultrafast spectroscopy, and open avenues toward the
possibility of analyzing and controlling the internal properties of quantum
nanodevices with pump-push photocurrent spectroscopy
Substitutability of Livestock Manure for Chemical Fertilizer: A Contingent Valuation Analysis of Crop Producers
The impact of new manure management regulations depends on the willingness of crop producers to accept manure. A contingent valuation analysis of crop producers was used to estimate the willingness of crop producers to accept or pay for manure. Results indicate that producers will pay a positive price on average, but some would require a payment before accepting manure.Farm Management,
Deterministic delivery of remote entanglement on a quantum network
Large-scale quantum networks promise to enable secure communication,
distributed quantum computing, enhanced sensing and fundamental tests of
quantum mechanics through the distribution of entanglement across nodes. Moving
beyond current two-node networks requires the rate of entanglement generation
between nodes to exceed their decoherence rates. Beyond this critical
threshold, intrinsically probabilistic entangling protocols can be subsumed
into a powerful building block that deterministically provides remote entangled
links at pre-specified times. Here we surpass this threshold using diamond spin
qubit nodes separated by 2 metres. We realise a fully heralded single-photon
entanglement protocol that achieves entangling rates up to 39 Hz, three orders
of magnitude higher than previously demonstrated two-photon protocols on this
platform. At the same time, we suppress the decoherence rate of remote
entangled states to 5 Hz by dynamical decoupling. By combining these results
with efficient charge-state control and mitigation of spectral diffusion, we
are able to deterministically deliver a fresh remote state with average
entanglement fidelity exceeding 0.5 at every clock cycle of 100 ms
without any pre- or post-selection. These results demonstrate a key building
block for extended quantum networks and open the door to entanglement
distribution across multiple remote nodes.Comment: v2 - updated to include relevant citatio
Expression levels influence ribosomal frameshifting at the tandem rare arginine codons AGG_AGG and AGA_AGA in Escherichia coli
Journal ArticleABSTRACT: The rare codons AGG and AGA comprise 2% and 4%, respectively, of the arginine codons of Escherichia coli K-12, and their cognate tRNAs are sparse. At tandem occurrences of either rare codon, the paucity of cognate aminoacyl tRNAs for the second codon of the pair facilitates peptidyl-tRNA shifting to the _x0001_1 frame. However, AGG_AGG and AGA_AGA are not underrepresented and occur 4 and 42 times, respectively, in E. coli genes. Searches for corresponding occurrences in other bacteria provide no strong support for the functional utilization of frameshifting at these sequences. All sequences tested in their native context showed 1.5 to 11% frameshifting when expressed from multicopy plasmids. A cassette with one of these sequences singly integrated into the chromosome in stringent cells gave 0.9% frameshifting in contrast to two- to four-times-higher values obtained from multicopy plasmids in stringent cells and eight-times-higher values in relaxed cells. Thus, _x0001_1 frameshifting efficiency at AGG_AGG and AGA_AGA is influenced by the mRNA expression level. These tandem rare codons do not occur in highly expressed mRNAs
Sanctions mémorielles et fragments littéraires au 1er siècle av. J.-C.
L\u27auteur "s\u27interroge (...) sur les liens pouvant exister entre l\u27état fragmentaire de différentes oeuvres latines du 1er siècle avant notre ère et les sanctions mémorielles, pouvant prendre la forme d\u27une véritable damnatio memoriae, sanctions auxquelles leurs auteurs respectifs ont été condamnés: Sylla, Marc Antoine et Caius Cornelius Gallus. De l\u27ouvrage considérable et novateur de Sylla, oeuvre autobiographique politique comportant vingt-deux livres, outre la trame fournie par Plutarque, il ne demeure que d\u27infimes fragments détachés de leurs contextes pour satisfaire la curiosité lexicologique et grammaticale d\u27auteurs tardifs (Aulu Gelle et Priscien). Marc Antoine fut littéralement réduit au silence par Auguste, son rival victorieux. Aucun fragment, au sens strict du terme, de ses écrits ne nous est parvenu. On ne connaît qu\u27une allusion à son pamphlet, De ebrietate sua, dans un passage de Pline, qui constitue une "destruction" en règle de l\u27ouvrage. De l\u27oeuvre de Gallus, poète élégiaque unanimement loué, il ne subsiste que deux fragments, dont l\u27un est transmis par un papyrus très endommagé. Tout laisse à penser que la disparition de son oeuvre s\u27explique par une censure, consécutive à la disgrâce qu\u27il subit, après avoir froissé Auguste..." (Fragments. Entre brisure et création, p.14-15)
Isolation of microsatellite loci in the Capricorn silvereye, Zosterops lateralis chlorocephalus (Aves : Zosteropidae)
The Capricorn silvereye (Zosterops lateralis chlorocephalus
) is ideally suited to investigating the genetic basis of body size evolution. We have isolated and characterized a set of microsatellite markers for this species. Seven out of 11 loci were polymorphic. The number of alleles
detected ranged from two to five and observed heterozygosities between 0.12 and 0.67. One locus, ZL49, was found to be sex-linked. This moderate level of diversity is consistent with that expected in an isolated, island population
Previous attentional set can induce an attentional blink with task-irrelevant initial targets
Identification of a second target is often impaired by the requirement to process a prior target in a rapid serial visual presentation (RSVP). This is termed the attentional blink. Even when the first target is task-irrelevant an attentional blink may occur providing this first target shares similar features with the second target (contingent capture). An RSVP experiment was undertaken to assess whether this first target can still cause an attentional blink when it did not require a response and did not share any features with the following target. The results revealed that such task-irrelevant targets can induce an attentional blink providing that they were task-relevant on a previous block of trials. This suggests that irrelevant focal stimuli can distract attention on the basis of a previous attentional set
On composite systems of dilute and dense couplings
Composite systems, where couplings are of two types, a combination of strong
dilute and weak dense couplings of Ising spins, are examined through the
replica method. The dilute and dense parts are considered to have independent
canonical disordered or uniform bond distributions; mixing the models by
variation of a parameter alongside inverse temperature we
analyse the respective thermodynamic solutions. We describe the variation in
high temperature transitions as mixing occurs; in the vicinity of these
transitions we exactly analyse the competing effects of the dense and sparse
models. By using the replica symmetric ansatz and population dynamics we
described the low temperature behaviour of mixed systems.Comment: 35 pages, 9 figures, submitted to JPhys
Development of a Critical Path Method Specification and a Training Program for use of CPM for KyTC
The Critical Path Method scheduling technique is outlined as it applies to KYTC projects. Special Provision 82 (94) and its requirements are outlined
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