4,243 research outputs found
Emergent Mott-insulators at non-integer fillings and devil's staircase induced by attractive interaction in many-body polarons
We investigate the ground state properties of an ultracold atom system
consisting of many-body polarons, quasiparticles formed by impurity atoms in
optical lattices immersing in a Bose-Einstein condensate. We find the
nearest-neighbor attractive interaction between polarons can give rise to rich
physics that is peculiar to this system. In a relatively shallow optical
lattice, the attractive interaction can drive the system being in a self-bound
superfluid phase with its particle density distribution manifesting a
self-concentrated structure. While in a relatively deep optical lattice, the
attractive interaction can drive the system forming the Mott-insulator phase
even though the global filling factor is not integer. Interestingly, in the
Mott-insulator regime, the system can support a series of different
Mott-insulators with their effective density manifesting a devil's staircase
structure with respect to the strength of attractive interaction. Detailed
estimation on relevant experimental parameters shows that these rich physics
can be readily observed in current experimental setups
Dual Long Short-Term Memory Networks for Sub-Character Representation Learning
Characters have commonly been regarded as the minimal processing unit in
Natural Language Processing (NLP). But many non-latin languages have
hieroglyphic writing systems, involving a big alphabet with thousands or
millions of characters. Each character is composed of even smaller parts, which
are often ignored by the previous work. In this paper, we propose a novel
architecture employing two stacked Long Short-Term Memory Networks (LSTMs) to
learn sub-character level representation and capture deeper level of semantic
meanings. To build a concrete study and substantiate the efficiency of our
neural architecture, we take Chinese Word Segmentation as a research case
example. Among those languages, Chinese is a typical case, for which every
character contains several components called radicals. Our networks employ a
shared radical level embedding to solve both Simplified and Traditional Chinese
Word Segmentation, without extra Traditional to Simplified Chinese conversion,
in such a highly end-to-end way the word segmentation can be significantly
simplified compared to the previous work. Radical level embeddings can also
capture deeper semantic meaning below character level and improve the system
performance of learning. By tying radical and character embeddings together,
the parameter count is reduced whereas semantic knowledge is shared and
transferred between two levels, boosting the performance largely. On 3 out of 4
Bakeoff 2005 datasets, our method surpassed state-of-the-art results by up to
0.4%. Our results are reproducible, source codes and corpora are available on
GitHub.Comment: Accepted & forthcoming at ITNG-201
Taxonomic studies on the subtribe Aphrastobraconina Ashmead (Hymenoptera: Braconidae: Braconinae) in China
The species of the subtribe Aphrastobraconina Ashmead from China were studied and five species belonging to three genera (Undabracon Quicke, 1986, Curriea Ashmead, 1900 and Aphrastobracon Ashmead, 1896) recognized. Three new species (Undabracon cariniventris sp. n., Aphrastobracon huanjiangensis sp. n. and A. politus sp. n.) are fully described and illustrated. The genus Undabracon (Quicke, 1986), the species Aphrastobracon flavipennis Ashmead and Curriea tibialis (Ashmead) are reported for the first time from China. A key to the species of the genus Undabracon is provided
Cloning and selection of reference genes for gene expression studies in Ananas comosus
Full length mRNA sequences of Ac-β-actin and Ac-gapdh, and partial mRNA sequences of Ac-18SrRNA and Ac-ubiquitin were cloned from pineapple in this study. The four genes were tested as housekeeping genes in three experimental sets. GeNorm and NormFinder analysis revealed that β-actin was the most appropriate reference gene for qPCR analysis of callus under induction conditions and in different tissue types, meanwhile, 18SrRNA was the most stable reference gene during organ development. Gapdh was the most unstable gene in all tested experimental sets. Transcript level analysis result of AcSERK1 in stressed callus normalized by β-actin and 18SrRNA further confirmed that reference genes selected in this study were suitable for transcript level analysis of pineapple. The expression pattern of AcSERK1 during somatic embryogenesis normalized by β-actin coincided with the cytological features of calluses during somatic embryogenesis. These results will enable more accurate and reliable normalization of qPCR results for transcription analysis in pineapple. Keywords: Reference genes, qPCR, pineapple, geNorm, NormFinder African Journal of Biotechnology Vol. 11(29), pp. 7424-7433, 10 April, 201
Triggers of Permo-Triassic boundary mass extinction in South China: the Siberian Traps or Paleo-Tethys ignimbrite flare-up?
Spindle oscillations are generated in the dorsal thalamus and modulated by the thalamic reticular nucleus
Spindle waves occur during the early stage of slow wave sleep and are thought to arise in the thalamic reticular nucleus (TRN), causing inhibitory postsynaptic potential spindle-like oscillations in the dorsal thalamus that are propagated to the cortex. We have found that thalamocortical neurons exhibit membrane oscillations that have spindle frequencies, consist of excitatory postsynaptic potentials, and co-occur with electroencephalographic spindles. TRN lesioning prolonged oscillations in the medial geniculate body (MGB) and auditory cortex (AC). Injection of GABA~A~ antagonist into the MGB decreased oscillation frequency, while injection of GABA~B~ antagonist increased spindle oscillations in the MGB and cortex. Thus, spindles originate in the dorsal thalamus and TRN inhibitory inputs modulate this process, with fast inhibition facilitating the internal frequency and slow inhibition limiting spindle occurrence
O,O′-Diisopropyl S-[2-(benzenesulfonamido)ethyl]phosphorodithioate
The molecular conformation of the title compound, C14H24NO4PS3, the selective herbicide bensulide, is stabilized by a weak intramolecular C—H⋯S interaction. In the crystal, chains are formed through intermolecular N—H⋯S hydrogen bonds
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