317 research outputs found
Research on Improving Online Purchase Intention of Poverty-Alleviation Agricultural Products in China: From the Perspective of Institution-Based Trust
Poverty alleviation by consumption is a powerful way to help the poor people get rid of poverty, which plays a significant role in China's rural revitalization. However, the achievement of poverty alleviation by consumption mostly depends on government procurement, and the enthusiasm of customers to participate is low, facing the severe challenge of poor sustainability. Helping the poor is the most common motivation for customers to buy poverty-alleviation agricultural products (PAAP). However, as the negative events of poverty alleviation such as “tragic marketing” constantly appear in news reports, customers' trust in sellers has been seriously damaged. The psychological protection system for fear of being cheated hinders customers' purchase intention. Therefore, we believed that trust is an important factor in enhancing customers' purchase intention of PAAP. Customers buy PAAP mainly through online channels, and institution-based trust is the most important way to generate trust in online channels. Thus, this study investigated the institutional mechanisms that affect customers' trust in the sellers of PAAP and discussed the influence of trust on the online purchase intention of PAAP. Data were obtained through a questionnaire survey and tested empirically. The results showed that the effectiveness of the user feedback mechanism, platform supervision mechanism, product traceability mechanism, and product certification mechanism can enhance customers' purchase intention by enhancing their trust. Individual trust tendency positively regulated the relationship between the effectiveness of institutional mechanisms and consumer trust. The conclusion can not only provide new theoretical guidance for the practice of poverty alleviation by consumption in China but also offer new ideas for the poverty alleviation undertakings in other countries
Study on Colour Reaction of Vanadium(V) with 2-(2-Quinolylazo)-5-Diethylaminophenol and Its Application
A sensitive, selective and rapid method has been developed for the determination of vanadium based on the rapid reaction of vanadium(V) with 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP). The QADEAP reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH =3.5) and cetyl trimethylammonium bromide (CTMAB) medium to form a violet chelate of a molar ratio 1:2 (V(V) to QADEAP). The molar absorptivity of the chelate is 1.23 x 105 L mol-1 cm-1 at 590 nm in the measured solution. Beer's law is obeyed in the range of 0.01~0.6 mg mL-1. This method was applied to the determination of vanadium(v) with good results.
South African Journal of Chemistry Vol.57 2004: 15-1
Analysis of internal crack healing mechanism under rolling deformation
A new experimental method, called the \u27hole filling method\u27, is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing mechanism. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic deformation, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic deformation followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion mechanism is used to explain the source of material needed for crack healing. The recrystallisation mechanism is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface
Exotic electronic states in gradient-strained untwisted graphene bilayers
Many exotic electronic states were discovered in moire superlattices hosted
in twisted homo-bilayers in the past decade, including unconventional
superconductivity and correlated insulating states. However, it is technically
challenging to precisely and orderly stack two or more layers into certain
twisting angles. Here, we presented a theoretical strategy that introduces
moire superlattices in untwisted homo-bilayers by applying different in-plane
strains on the two layers of a graphene homo-bilayer, respectively. Our density
functional theory calculations indicate that the graphene bilayer exhibits
substantial out-of-plane corrugations that form a coloring-triangular structure
in each moire supercell under gradient in-plane strains. Such structure leads
to a set of kagome bands, namely one flat-band and, at least, one Dirac band,
developing along the M-K path after band-folding. For comparison, uniformly
applied in-plane strain only yields a nearly flat band within path K-G, which
is originated from local quantum confinement. These findings highlight the
gradient strain as a route to feasibly fabricate exotic electronic states in
untwisted flexible homo-bilayers.Comment: 15 pages, 4 figure
Unsupervised Adaptation for High-Dimensional with Limited-Sample Data Classification Using Variational Autoencoder
High-dimensional with limited-sample size (HDLSS) datasets exhibit two critical problems: (1) Due to the insufficiently small-sample size, there is a lack of enough samples to build classification models. Classification models with a limited-sample may lead to overfitting and produce erroneous or meaningless results. (2) The 'curse of dimensionality' phenomena is often an obstacle to the use of many methods for solving the high-dimensional with limited-sample size problem and reduces classification accuracy. This study proposes an unsupervised framework for high-dimensional limited-sample size data classification using dimension reduction based on variational autoencoder (VAE). First, the deep learning method variational autoencoder is applied to project high-dimensional data onto lower-dimensional space. Then, clustering is applied to the obtained latent-space of VAE to find the data groups and classify input data. The method is validated by comparing the clustering results with actual labels using purity, rand index, and normalized mutual information. Moreover, to evaluate the proposed model strength, we analyzed 14 datasets from the Arizona State University Digital Repository. Also, an empirical comparison of dimensionality reduction techniques shown to conclude their applicability in the high-dimensional with limited-sample size data settings. Experimental results demonstrate that variational autoencoder can achieve more accuracy than traditional dimensionality reduction techniques in high-dimensional with limited-sample-size data analysis
Topic Sentiment Joint Model with Word Embeddings
Abstract. Topic sentiment joint model is an extended model which aims to deal with the problem of detecting sentiments and topics simultaneously from online reviews. Most of existing topic sentiment joint modeling algorithms infer resulting distributions from the co-occurrence of words. But when the training corpus is short and small, the resulting distributions might be not very satisfying. In this paper, we propose a novel topic sentiment joint model with word embeddings (TSWE), which introduces word embeddings trained on external large corpus. Furthermore, we implement TSWE with Gibbs sampling algorithms. The experiment results on Chinese and English data sets show that TSWE achieves significant performance in the task of detecting sentiments and topics simultaneously
Performance of several simple, noninvasive models for assessing significant liver fibrosis in patients with chronic hepatitis B
Aim To compare the performance of several simple, noninvasive
models comprising various serum markers in diagnosing
significant liver fibrosis in the same sample of
patients with chronic hepatitis B (CHB) with the same judgment
standard.
Methods A total of 308 patients with CHB who had undergone
liver biopsy, laboratory tests, and liver stiffness
measurement (LSM) at the Southwest Hospital, Chongqing,
China between March 2010 and April 2014 were retrospectively
studied. Receiver operating characteristic (ROC)
curves and area under ROC curves (AUROCs) were used to
analyze the results of the models, which incorporated ageplatelet
(PLT) index (API model), aspartate transaminase
(AST) to alanine aminotransferase (ALT) ratio (AAR model),
AST to PLT ratio index (APRI model), Îł-glutamyl transpeptidase
(GGT) to PLT ratio index (GPRI model), GGT-PLT-albumin
index (S index model), age-AST-PLT-ALT index (FIB-4
model), and age-AST-PLT-ALT-international normalized ratio
index (Fibro-Q model).
Results The AUROCs of the S index, GPRI, FIB-4, APRI, API,
Fibro-Q, AAR, and LSM for predicting significant liver fibrosis
were 0.726 (P < 0.001), 0.726 (P < 0.001), 0.621 (P = 0.001),
0.619 (P = 0.001), 0.580 (P = 0.033), 0.569 (P = 0.066), 0.495
(P = 0.886), and 0.757 (P < 0.001), respectively. The S index
and GPRI had the highest correlation with histopathological
scores (r = 0.373, P < 0.001; r = 0.372, P < 0.001, respectively)
and LSM values (r = 0.516, P < 0.001; r = 0.513,
P < 0.001, respectively). When LSM was combined with S
index and GPRI, the AUROCs were 0.753 (P < 0.001) and
0.746 (P < 0.001), respectively.
Conclusion S index and GPRI had the best diagnostic performance
for significant liver fibrosis and were robust predictors
of significant liver fibrosis in patients with CHB for
whom transient elastography was unavailable
Communicative focus on form and second language suprasegmental learning: teaching Cantonese learners to perceive mandarin tones
The current study examined how form-focused instruction (FFI) with and without corrective feedback (CF) as output enhancement can facilitate L2 perception of Mandarin tones at both the phonetic and phonological levels in 41 Cantonese learners of Mandarin. Two experimental groups, FFI-only and FFI-CF, received a 90-minute FFI treatment designed to encourage them to notice and practice the categorical distinctions of Mandarin tones through a range of communicative input and output activities. During these activities, the instructors provided CF only to students in the FFI-CF group by recasting and pushing them to repair their mispronunciations of the target features (i.e., output enhancement). The control group received comparable meaning-oriented instruction without any FFI. The effectiveness of FFI was assessed via a forced-choice identification task with both trained and untrained items for a variety of tonal contrasts in Mandarin (high level Tone 1 vs. mid-rising Tone 2 vs. high falling Tone 4). According to statistical comparisons, the FFI-only group attained significant improvement in all lexical and tonal contexts, and such effectiveness was evident particularly in the acquisition of Tone 1 and Tone 4—supposedly the most difficult instances due to their identical phonological status in the learners’ L1, Cantonese. The FFI-CF group, however, demonstrated marginally significant gains only under the trained lexical conditions. The results in turn suggest that FFI promotes learners’ attentional shift from vocabulary to sound learning (generalizable gains in trained and untrained items) and facilitates their access to new phonetic and phonological categories. Yet, the relative advantage of adding CF to FFI as output enhancement remains unclear, especially with respect to the less experienced L2 learners in the current study
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Slc39a7/zip7 Plays a Critical Role in Development and Zinc Homeostasis in Zebrafish
Background: Slc39a7/Zip7, also known as Ke4, is a member of solute carrier family 39 (Slc39a) and plays a critical role in regulating cell growth and death. Because the function of Zip7 in vivo was unclear, the present study investigated the function of zip7 in vertebrate development and zinc metabolism using zebrafish as a model organism. Principal Finding: Using real-time PCR to determine the gene expression pattern of zip7 during zebrafish development, we found that zip7 mRNA is expressed throughout embryonic development and into maturity. Interestingly, whole mount in situ hybridization revealed that while zip7 mRNA is ubiquitously expressed until 12 hours post-fertilization (hpf); at 24 hpf and beyond, zip7 mRNA was specifically detected only in eyes. Morpholino-antisense (MO) gene knockdown assay revealed that downregulation of zip7 expression resulted in several morphological defects in zebrafish including decreased head size, smaller eyes, shorter palates, and shorter and curved spinal cords. Analysis by synchrotron radiation X-ray fluorescence (SR-XRF) showed reduced concentrations of zinc in brain, eyes, and gills of zip7-MO-injected embryos. Furthermore, incubation of the zip7 knockdown embryos in a zinc-supplemented solution was able to rescue the MO-induced morphological defects. Significance: Our data suggest that zip7 is required for eye, brain, and skeleton formation during early embryonic development in zebrafish. Moreover, zinc supplementation can partially rescue defects resulting from zip7 gene knockdown. Taken together, our data provide critical insight into a novel function of zip7 in development and zinc homeostasis in vivo in zebrafish
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