140 research outputs found
Development of high resolution arrayed waveguide grating spectrometers for astronomical applications: first results
Astrophotonics is the next-generation approach that provides the means to
miniaturize near-infrared (NIR) spectrometers for upcoming large telescopes and
make them more robust and inexpensive. The target requirements for our
spectrograph are: a resolving power of about 3000, wide spectral range (J and H
bands), free spectral range of about 30 nm, high on-chip throughput of about
80% (-1dB) and low crosstalk (high contrast ratio) between adjacent on-chip
wavelength channels of less than 1% (-20dB). A promising photonic technology to
achieve these requirements is Arrayed Waveguide Gratings (AWGs). We have
developed our first generation of AWG devices using a silica-on-silicon
substrate with a very thin layer of silicon-nitride in the core of our
waveguides. The waveguide bending losses are minimized by optimizing the
geometry of the waveguides. Our first generation of AWG devices are designed
for H band and have a resolving power of around 1500 and free spectral range of
about 10 nm around a central wavelength of 1600 nm. The devices have a
footprint of only 12 mm x 6 mm. They are broadband (1450-1650 nm), have a peak
on-chip throughput of about 80% (-1 dB) and contrast ratio of about 1.5% (-18
dB). These results confirm the robustness of our design, fabrication and
simulation methods. Currently, the devices are designed for Transverse Electric
(TE) polarization and all the results are for TE mode. We are developing
separate J- and H-band AWGs with higher resolving power, higher throughput and
lower crosstalk over a wider free spectral range to make them better suited for
astronomical applications.Comment: 12 pages, 13 figures, 3 tables. SPIE Astronomical Telescopes and
Instrumentation, Edinburgh (26 June - 1 July, 2016
Exploiting Emotion-Semantic Correlations for Empathetic Response Generation
Empathetic response generation aims to generate empathetic responses by
understanding the speaker's emotional feelings from the language of dialogue.
Recent methods capture emotional words in the language of communicators and
construct them as static vectors to perceive nuanced emotions. However,
linguistic research has shown that emotional words in language are dynamic and
have correlations with other grammar semantic roles, i.e., words with semantic
meanings, in grammar. Previous methods overlook these two characteristics,
which easily lead to misunderstandings of emotions and neglect of key
semantics. To address this issue, we propose a dynamical Emotion-Semantic
Correlation Model (ESCM) for empathetic dialogue generation tasks. ESCM
constructs dynamic emotion-semantic vectors through the interaction of context
and emotions. We introduce dependency trees to reflect the correlations between
emotions and semantics. Based on dynamic emotion-semantic vectors and
dependency trees, we propose a dynamic correlation graph convolutional network
to guide the model in learning context meanings in dialogue and generating
empathetic responses. Experimental results on the EMPATHETIC-DIALOGUES dataset
show that ESCM understands semantics and emotions more accurately and expresses
fluent and informative empathetic responses. Our analysis results also indicate
that the correlations between emotions and semantics are frequently used in
dialogues, which is of great significance for empathetic perception and
expression.Comment: 12 pages, 3 figures, Findings of EMNLP 202
Genome-wide identification of germin-like proteins in peanut (Arachis hypogea L.) and expression analysis under different abiotic stresses
Peanut is an important food and feed crop, providing oil and protein nutrients. Germins and germin-like proteins (GLPs) are ubiquitously present in plants playing numerous roles in defense, growth and development, and different signaling pathways. However, the GLP members have not been comprehensively studied in peanut at the genome-wide scale. We carried out a genome-wide identification of the GLP genes in peanut genome. GLP members were identified comprehensively, and gene structure, genomic positions, motifs/domains distribution patterns, and phylogenetic history were studied in detail. Promoter Cis-elements, gene duplication, collinearity, miRNAs, protein-protein interactions, and expression were determined. A total of 84 GLPs (AhGLPs ) were found in the genome of cultivated peanut. These GLP genes were clustered into six groups. Segmental duplication events played a key role in the evolution of AhGLPs, and purifying selection pressure was underlying the duplication process. Most AhGLPs possessed a well-maintained gene structure and motif organization within the same group. The promoter regions of AhGLPs contained several key cis-elements responsive to ‘phytohormones’, ‘growth and development’, defense, and ‘light induction’. Seven microRNAs (miRNAs) from six families were found targeting 25 AhGLPs. Gene Ontology (GO) enrichment analysis showed that AhGLPs are highly enriched in nutrient reservoir activity, aleurone grain, external encapsulating structure, multicellular organismal reproductive process, and response to acid chemicals, indicating their important biological roles. AhGLP14, AhGLP38, AhGLP54, and AhGLP76 were expressed in most tissues, while AhGLP26, AhGLP29, and AhGLP62 showed abundant expression in the pericarp. AhGLP7, AhGLP20, and AhGLP21, etc., showed specifically high expression in embryo, while AhGLP12, AhGLP18, AhGLP40, AhGLP78, and AhGLP82 were highly expressed under different hormones, water, and temperature stress. The qRT-PCR results were in accordance with the transcriptome expression data. In short, these findings provided a foundation for future functional investigations on the AhGLPs for peanut breeding programs
A Novel Recombinant Peste des Petits Ruminants-Canine Adenovirus Vaccine Elicits Long-Lasting Neutralizing Antibody Response against PPR in Goats
BACKGROUND: Peste des petits ruminants (PPR) is a highly contagious infectious disease of goats, sheep and small wild ruminant species with high morbidity and mortality rates. The Peste des petits ruminants virus (PPRV) expresses a hemagglutinin (H) glycoprotein on its outer envelope that is crucial for viral attachment to host cells and represents a key antigen for inducing the host immune response. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether H can be exploited to generate an effective PPRV vaccine, a replication-competent recombinant canine adenovirus type-2 (CAV-2) expressing the H gene of PPRV (China/Tibet strain) was constructed by the in vitro ligation method. The H expression cassette, including the human cytomegalovirus (hCMV) promoter/enhancer and the BGH early mRNA polyadenylation signal, was inserted into the SspI site of the E3 region, which is not essential for proliferation of CAV-2. Infectious recombinant rCAV-2-PPRV-H virus was generated in transfected MDCK cells and used to immunize goats. All vaccinated animals produced antibodies upon primary injection that were effective in neutralizing PPRV in vitro. Higher antibody titer was obtained following booster inoculation, and the antibody was detectable in goats for at least seven months. No serious recombinant virus-related adverse effect was observed in immunized animals and no adenovirus could be isolated from the urine or feces of vaccinated animals. Results showed that the recombinant virus was safe and could stimulate a long-lasting immune response in goats. CONCLUSIONS/SIGNIFICANCE: This strategy not only provides an effective PPR vaccine candidate for goats but may be a valuable mean by which to differentiate infected from vaccinated animals (the so-called DIVA approach)
The LVRT Control Scheme for PMSG-Based Wind Turbine Generator Based on the Coordinated Control of Rotor Overspeed and Supercapacitor Energy Storage
With the increasing penetration level of wind turbine generators (WTGs) integrated into the power system, the WTGs are enforced to aid network and fulfill the low voltage ride through (LVRT) requirements during faults. To enhance LVRT capability of permanent magnet synchronous generator (PMSG)-based WTG connected to the grid, this paper presents a novel coordinated control scheme named overspeed-while-storing control for PMSG-based WTG. The proposed control scheme purely regulates the rotor speed to reduce the input power of the machine-side converter (MSC) during slight voltage sags. Contrarily, when the severe voltage sag occurs, the coordinated control scheme sets the rotor speed at the upper-limit to decrease the input power of the MSC at the greatest extent, while the surplus power is absorbed by the supercapacitor energy storage (SCES) so as to reduce its maximum capacity. Moreover, the specific capacity configuration scheme of SCES is detailed in this paper. The effectiveness of the overspeed-while-storing control in enhancing the LVRT capability is validated under different levels of voltage sags and different fault types in MATLAB/Simulink
Techniques adopted in the rice azolla fish system with ridge culture
Meeting: National Rice Fish Farming Systems Symposium, 4-8 Oct. 1988, Wuxi, CNIn IDL-1614
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