5,363 research outputs found
Fabrication and tuning of plasmonic optical nanoantennas around droplet epitaxy quantum dots by cathodoluminescence
We use cathodoluminescence to locate droplet epitaxy quantum dots with a
precision nm before fabricating nanoantennas in their vicinity by
electron-beam lithography. Cathodoluminescence is further used to evidence the
effect of the antennas as a function of their length on the light emitted by
the dot. Experimental results are in good agreement with numerical simulations
of the structures
Joint Video and Text Parsing for Understanding Events and Answering Queries
We propose a framework for parsing video and text jointly for understanding
events and answering user queries. Our framework produces a parse graph that
represents the compositional structures of spatial information (objects and
scenes), temporal information (actions and events) and causal information
(causalities between events and fluents) in the video and text. The knowledge
representation of our framework is based on a spatial-temporal-causal And-Or
graph (S/T/C-AOG), which jointly models possible hierarchical compositions of
objects, scenes and events as well as their interactions and mutual contexts,
and specifies the prior probabilistic distribution of the parse graphs. We
present a probabilistic generative model for joint parsing that captures the
relations between the input video/text, their corresponding parse graphs and
the joint parse graph. Based on the probabilistic model, we propose a joint
parsing system consisting of three modules: video parsing, text parsing and
joint inference. Video parsing and text parsing produce two parse graphs from
the input video and text respectively. The joint inference module produces a
joint parse graph by performing matching, deduction and revision on the video
and text parse graphs. The proposed framework has the following objectives:
Firstly, we aim at deep semantic parsing of video and text that goes beyond the
traditional bag-of-words approaches; Secondly, we perform parsing and reasoning
across the spatial, temporal and causal dimensions based on the joint S/T/C-AOG
representation; Thirdly, we show that deep joint parsing facilitates subsequent
applications such as generating narrative text descriptions and answering
queries in the forms of who, what, when, where and why. We empirically
evaluated our system based on comparison against ground-truth as well as
accuracy of query answering and obtained satisfactory results
Decay dynamics and exciton localization in large GaAs quantum dots grown by droplet epitaxy
We investigate the optical emission and decay dynamics of excitons confined
in large strain-free GaAs quantum dots grown by droplet epitaxy. From
time-resolved measurements combined with a theoretical model we show that
droplet-epitaxy quantum dots have a quantum efficiency of about 75% and an
oscillator strength between 8 and 10. The quantum dots are found to be fully
described by a model for strongly-confined excitons, in contrast to the
theoretical prediction that excitons in large quantum dots exhibit the
so-called giant oscillator strength. We attribute these findings to localized
ground-state excitons in potential minima created by material intermixing
during growth. We provide further evidence for the strong-confinement regime of
excitons by extracting the size of electron and hole wavefunctions from the
phonon-broadened photoluminescence spectra. Furthermore, we explore the
temperature dependence of the decay dynamics and, for some quantum dots,
observe a pronounced reduction in the effective transition strength with
temperature. We quantify and explain these effects as being an intrinsic
property of large quantum dots owing to thermal excitation of the ground-state
exciton. Our results provide a detailed understanding of the optical properties
of large quantum dots in general, and of quantum dots grown by droplet epitaxy
in particular.Comment: 13 pages, 7 figure
Revisiting The Certifying Role Of Financial Intermediaries On IPOs
This paper re-examines the role of commercial banks, investment banks, and venture capitalists in monitoring and certifying the value of the firms that went public in the 2000s. We find that investment banks that have better reputations are associated with larger underpricing for venture-capital-backed IPOs, but not for non-venture-capital-backed IPOs. The partial adjustment phenomenon observed in Carter et al. (2001) exists only for venture-capital-backed IPOs. The presence of venture capital is inversely related to IPO underpricing only when venture capitalists certify small firms. We do not find that the presence of bank debt reduces IPO underpricing. In addition, we do not find any substitutive or complementary role between commercial banks and venture capitalists in certifying IPOs
Eutrophication and succession of phytoplankton in reservoir of Korea - monthly variations of plankton community in Lake Soyang
The community of plankton and the environmental factors were investigated in Lake Soyang from January to July 1994. The relationship between transparency and biovolume of phytoplankton was negatively correlated. Phytoplankton dominants in Lake Soyang were Anabaena spp., Microcystis aeruginosa, Asterionella formosa, Asterionella gracillima Melosira distans, Synedra acus, and Asterococcus limneticus, Zooplankton dominants were Polyarthra spp., Keratella spp., Asplanchna placentula, Bosmina coregoni, and Daphnia longispona. Phytoplankton and zooplankton were clearly related each other with respect to biovolume, not to numbers. Microcystis aeruginosa rapidly increased and Daphnia longirostris disappeared in July, because Microcystis aeruginosa secret toxic substances to Daphnia longirostris. Transparency decreased from January to June, but increased in July. The highest number of phytoplankton was obserbed in April, and one month later, the zooplankton reached a maximal level in population density, implicating that spring bloom of phytoplankton was good feeding condition for zooplankton.Article信州大学理学部附属諏訪臨湖実験所報告 9: 175-186(1995)departmental bulletin pape
Multiple Functions of Nm23-H1 Are Regulated by Oxido-Reduction System
Nucleoside diphosphate kinase (NDPK, Nm23), a housekeeping enzyme, is known to be a multifunctional protein, acting as a metastasis suppressor, transactivation activity on c-myc, and regulating endocytosis. The cellular mechanisms regulating Nm23 functions are poorly understood. In this study, we identified the modifications and interacting proteins of Nm23-H1 in response to oxidative stress. We found that Cys109 in Nm23-H1 is oxidized to various oxidation states including intra- and inter-disulfide crosslinks, glutathionylation, and sulfonic acid formation in response to H2O2 treatment both in vivo and in vitro. The cross-linking sites and modifications of oxidized Nm23-H1 were identified by peptide sequencing using UPLC-ESI-q-TOF tandem MS. Glutathionylation and oxidation of Cys109 inhibited the NDPK enzymatic activity of Nm23-H1. We also found that thioredoxin reductase 1 (TrxR1) is an interacting protein of Nm23-H1, and it binds specifically to oxidized Nm23-H1. Oxidized Nm23 is a substrate of NADPH-TrxR1-thioredoxin shuttle system, and the disulfide crosslinking is reversibly reduced and the enzymatic activity is recovered by this system. Oxidation of Cys109 in Nm23-H1 inhibited its metastatic suppressor activity as well as the enzymatic activities. The mutant, Nm23-H1 C109A, retained both the enzymatic and metastasis suppressor activities under oxidative stress. This suggests that key enzymatic and metastasis suppressor functions of Nm23-H1 are regulated by oxido-reduction of its Cys109
Efficacy and Tolerability of GCSB-5 for Hand Osteoarthritis: A Randomized, Controlled Trial
AbstractPurposeThe aim of this study was to investigate the efficacy and tolerability of GCSB-5, a mixture of 6 purified herbal extracts, in treating hand osteoarthritis (OA).MethodsA randomized, double-blind, placebo-controlled trial enrolled 220 patients with hand OA who had baseline a visual analog scale joint pain score of >30 of 100 mm at 3 hospitals between September 2013 and November 2014. After randomization, patients were allocated to receive oral GCSB-5 600 mg or placebo, bid for 12 weeks. The primary end point was the change in the Australian/Canadian OA Hand Index (AUSCAN)-defined pain score at 4 weeks relative to baseline. Secondary end points included the frequency Outcome Measures in Rheumatology–OA Research Society International (OMERACT-OARSI)-defined response at 4, 8, 12, and 16 weeks after randomization.FindingsThe allocated treatment was received by 109 and 106 patients in the GCSB-5 and placebo groups, respectively. At 4 weeks, the median (interquartile range) change in AUSCAN pain score relative to baseline was significantly greater in the GCSB-5 group than in the placebo group (–9.0 [–23.8 to –0.4] vs –2.2 [–16.7 to 6.0]; P = 0.014), with sustained improvement at 8, 12, and 16 weeks (P = 0.039). The GCSB-5 group also had a significantly greater OMERACT-OARSI–defined response rate than did the placebo group at 4 weeks (44.0% vs 30.2%), 8 weeks (51.4% vs 35.9%), 12 weeks (56.9% vs 40.6%), and 16 weeks (50.5% vs 37.7%) (P = 0.0074). The 2 treatments exhibited comparable safety profiles.ImplicationsGCSB-5 was associated with improved symptoms of hand OA, with good tolerability, in these patients. GCSB-5 may be a well-tolerated alternative of, or addition to, the treatment of hand OA. ClinicalTrials.gov identifier: NCT01910116
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