1,066 research outputs found
Exploring The Media Strategy For International Marketers With Small Budgets: A Cross-Country Consumer Perspective
This paper reports a cross-country comparative study of the media choices for the marketing of Master of Business Administration education in China and the United States from a consumer perspective. To date, limited discussion in the standardization versus adaptation debate has focused specifically on the issue of media strategy from the perspective of a specific category of international marketers, even though media planning is often the most costly and challenging part of international marketing communication. The current study is an effort to bridge this gap
Experimental investigation of film cooling effectiveness on gas turbine blades
The hot gas temperature in gas turbine engines is far above the permissible metal temperatures. Advanced cooling technologies must be applied to cool the blades, so they can withstand the extreme conditions. Film cooling is widely used in modern high temperature and high pressure blades as an active cooling scheme. In this study, the film cooling effectiveness in different regions of gas turbine blades was investigated with various film hole/slot configurations and mainstream flow conditions. The study consisted of four parts: 1) effect of upstream wake on blade surface film cooling, 2) effect of upstream vortex on platform purge flow cooling, 3) influence of hole shape and angle on leading edge film cooling and 4) slot film cooling on trailing edge. Pressure sensitive paint (PSP) technique was used to get the conduction-free film cooling effectiveness distribution. For the blade surface film cooling, the effectiveness from axial shaped holes and compound angle shaped holes were examined. Results showed that the compound angle shaped holes offer better film effectiveness than the axial shaped holes. The upstream stationary wakes have detrimental effect on film effectiveness in certain wake rod phase positions. For platform purge flow cooling, the stator-rotor gap was simulated by a typical labyrinth-like seal. Delta wings were used to generate vortex and modeled the passage vortex generated by the upstream vanes. Results showed that the upstream vortex reduces the film cooling effectiveness on the platform. For the leading edge film cooling, two film cooling designs, each with four film cooling hole configurations, were investigated. Results showed that the shaped holes provide higher film cooling effectiveness than the cylindrical holes at higher average blowing ratios. In the same range of average blowing ratio, the radial angle holes produce better effectiveness than the compound angle holes. The seven-row design results in much higher effectiveness than the three-row design. For the trailing edge slot cooling, the effect of slot lip thickness on film effectiveness under the two mainstream conditions was investigated. Results showed thinner lips offer higher effectiveness. The film effectiveness on the slots reduces when the incoming mainstream boundary layer thickness decreases
APETALA2 antagonizes the transcriptional activity of AGAMOUS in regulating floral stem cells in Arabidopsis thaliana.
APETALA2 (AP2) is best known for its function in the outer two floral whorls, where it specifies the identities of sepals and petals by restricting the expression of AGAMOUS (AG) to the inner two whorls in Arabidopsis thaliana. Here, we describe a role of AP2 in promoting the maintenance of floral stem cell fate, not by repressing AG transcription, but by antagonizing AG activity in the center of the flower. We performed a genetic screen with ag-10 plants, which exhibit a weak floral determinacy defect, and isolated a mutant with a strong floral determinacy defect. This mutant was found to harbor another mutation in AG and was named ag-11. We performed a genetic screen in the ag-11 background to isolate mutations that suppress the floral determinacy defect. Two suppressor mutants were found to harbor mutations in AP2. While AG is known to shut down the expression of the stem cell maintenance gene WUSCHEL (WUS) to terminate floral stem cell fate, AP2 promotes the expression of WUS. AP2 does not repress the transcription of AG in the inner two whorls, but instead counteracts AG activity
Establishment, optimization, and application of genetic technology in Aspergillus spp.
Aspergillus is widely distributed in nature and occupies a crucial ecological niche, which has complex and diverse metabolic pathways and can produce a variety of metabolites. With the deepening of genomics exploration, more Aspergillus genomic informations have been elucidated, which not only help us understand the basic mechanism of various life activities, but also further realize the ideal functional transformation. Available genetic engineering tools include homologous recombinant systems, specific nuclease based systems, and RNA techniques, combined with transformation methods, and screening based on selective labeling. Precise editing of target genes can not only prevent and control the production of mycotoxin pollutants, but also realize the construction of economical and efficient fungal cell factories. This paper reviewed the establishment and optimization process of genome technologies, hoping to provide the theoretical basis of experiments, and summarized the recent progress and application in genetic technology, analyzes the challenges and the possibility of future development with regard to Aspergillus
Selection of reliable reference genes for gene expression studies in peach using real-time PCR
<p>Abstract</p> <p>Background</p> <p>RT-qPCR is a preferred method for rapid and reliable quantification of gene expression studies. Appropriate application of RT-qPCR in such studies requires the use of reference gene(s) as an internal control to normalize mRNA levels between different samples for an exact comparison of gene expression level. However, recent studies have shown that no single reference gene is universal for all experiments. Thus, the identification of high quality reference gene(s) is of paramount importance for the interpretation of data generated by RT-qPCR. Only a few studies on reference genes have been done in plants and none in peach <it>(Prunus persica </it>L. Batsch). Therefore, the present study was conducted to identify suitable reference gene(s) for normalization of gene expression in peach.</p> <p>Results</p> <p>In this work, eleven reference genes were investigated in different peach samples using RT-qPCR with SYBR green. These genes are: actin 2/7 (<it>ACT</it>), cyclophilin (<it>CYP2</it>), RNA polymerase II (<it>RP II</it>), phospholipase A2 (<it>PLA2</it>), ribosomal protein L13 (<it>RPL13</it>), glyceraldehyde-3-phosphate dehydrogenase (<it>GAPDH</it>), 18S ribosomal RNA (<it>18S rRNA</it>), tubblin beta (<it>TUB</it>), tubblin alpha (<it>TUA</it>), translation elongation factor 2 (<it>TEF2</it>) and ubiquitin 10 (<it>UBQ10</it>). All eleven reference genes displayed a wide range of C<sub>q </sub>values in all samples, indicating that they expressed variably. The stability of these genes except for <it>RPL13 </it>was determined by three different descriptive statistics, geNorm, NormFinder and BestKeeper, which produced highly comparable results.</p> <p>Conclusion</p> <p>Our study demonstrates that expression stability varied greatly between genes studied in peach. Based on the results from geNorm, NormFinder and BestKeeper analyses, for all the sample pools analyzed, <it>TEF2</it>, <it>UBQ10 </it>and <it>RP II </it>were found to be the most suitable reference genes with a very high statistical reliability, and <it>TEF2 </it>and <it>RP II </it>for the other sample series, while <it>18S rRNA</it>, <it>RPL13 </it>and <it>PLA2 </it>were unsuitable as internal controls. <it>GAPDH </it>and <it>ACT </it>also performed poorly and were less stable in our analysis. To achieve accurate comparison of levels of gene expression, two or more reference genes must be used for data normalization. The combinations of <it>TEF2</it>/<it>UBQ10/RP II </it>and <it>TEF2/RP II </it>were suggested for use in all samples and subsets, respectively.</p
Unveiling the nucleon tensor charge at Jefferson Lab: A study of the SoLID case
Future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the
Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in
the region where the partonic structure of the nucleon is dominated by the
valence quarks. One of the main goals is to constrain the quark transversity
distributions. We apply recent theoretical advances of the global QCD
extraction of the transversity distributions to study the impact of future
experimental data from the SoLID experiments. Especially, we develop a simple
strategy based on the Hessian matrix analysis that allows one to estimate the
uncertainties of the transversity quark distributions and their tensor charges
extracted from SoLID data simulation. We find that the SoLID measurements with
the proton and the effective neutron targets can improve the precision of the
u- and d-quark transversity distributions up to one order of magnitude in the
range 0.05 < x < 0.6.Comment: 11 pages, 3 figures, published on Physics Letters
Pre-training Multi-task Contrastive Learning Models for Scientific Literature Understanding
Scientific literature understanding tasks have gained significant attention
due to their potential to accelerate scientific discovery. Pre-trained language
models (LMs) have shown effectiveness in these tasks, especially when tuned via
contrastive learning. However, jointly utilizing pre-training data across
multiple heterogeneous tasks (e.g., extreme multi-label paper classification,
citation prediction, and literature search) remains largely unexplored. To
bridge this gap, we propose a multi-task contrastive learning framework,
SciMult, with a focus on facilitating common knowledge sharing across different
scientific literature understanding tasks while preventing task-specific skills
from interfering with each other. To be specific, we explore two techniques --
task-aware specialization and instruction tuning. The former adopts a
Mixture-of-Experts Transformer architecture with task-aware sub-layers; the
latter prepends task-specific instructions to the input text so as to produce
task-aware outputs. Extensive experiments on a comprehensive collection of
benchmark datasets verify the effectiveness of our task-aware specialization
strategy, where we outperform state-of-the-art scientific pre-trained LMs.
Code, datasets, and pre-trained models can be found at
https://scimult.github.io/.Comment: 17 pages; Accepted to Findings of EMNLP 2023 (Project Page:
https://scimult.github.io/
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