2,200 research outputs found
The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China.
This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO₂e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO₂e is 8215.31 tons. Based on the evaluation results, the CO₂e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO₂e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO₂e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO₂ in each phase, which accounts for more than 98% of total emissions. N₂O and CH₄ emissions are relatively insignificant
Functional conservation and divergence of Miscanthus lutarioriparius GT43 gene family in xylan biosynthesis
Background: Xylan is the most abundant un-cellulosic polysaccharides of plant cell walls. Much progress in xylan biosynthesis has been gained in the model plant species Arabidopsis. Two homologous pairs Irregular Xylem 9 (IRX9)/9L and IRX14/14L from glycosyltransferase (GT) family 43 have been proved to play crucial roles in xylan backbone biosynthesis. However, xylan biosynthesis in grass such as Miscanthus remains poorly understood
Composition, variation, expression and evolution of low-molecular-weight glutenin subunit genes in Triticum urartu
BACKGROUND: Wheat (AABBDD, 2n = 6x = 42) is a major dietary component for many populations across the world. Bread-making quality of wheat is mainly determined by glutenin subunits, but it remains challenging to elucidate the composition and variation of low-molecular-weight glutenin subunits (LMW-GS) genes, the major components for glutenin subunits in hexaploid wheat. This problem, however, can be greatly simplified by characterizing the LMW-GS genes in Triticum urartu, the A-genome donor of hexaploid wheat. In the present study, we exploited the high-throughput molecular marker system, gene cloning, proteomic methods and molecular evolutionary genetic analysis to reveal the composition, variation, expression and evolution of LMW-GS genes in a T. urartu population from the Fertile Crescent region. RESULTS: Eight LMW-GS genes, including four m-type, one s-type and three i-type, were characterized in the T. urartu population. Six or seven genes, the highest number at the Glu-A3 locus, were detected in each accession. Three i-type genes, each containing more than six allelic variants, were tightly linked because of their co-segregation in every accession. Only 2-3 allelic variants were detected for each m- and s-type gene. The m-type gene, TuA3-385, for which homologs were previously characterized only at Glu-D3 locus in common wheat and Aegilops tauschii, was detected at Glu-A3 locus in T. urartu. TuA3-460 was the first s-type gene identified at Glu-A3 locus. Proteomic analysis showed 1-4 genes, mainly i-type, expressed in individual accessions. About 62% accessions had three active i-type genes, rather than one or two in common wheat. Southeastern Turkey might be the center of origin and diversity for T. urartu due to its abundance of LMW-GS genes/genotypes. Phylogenetic reconstruction demonstrated that the characterized T. urartu might be the direct donor of the Glu-A3 locus in common wheat varieties. CONCLUSIONS: Compared with the Glu-A3 locus in common wheat, a large number of highly diverse LMW-GS genes and active genes were characterized in T. urartu, demonstrating that this progenitor might provide valuable genetic resources for LMW-GS genes to improve the quality of common wheat. The phylogenetic analysis provided molecular evidence and confirmed that T. urartu was the A-genome donor of hexaploid wheat. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-014-0322-3) contains supplementary material, which is available to authorized users
Wasserstein Differential Privacy
Differential privacy (DP) has achieved remarkable results in the field of
privacy-preserving machine learning. However, existing DP frameworks do not
satisfy all the conditions for becoming metrics, which prevents them from
deriving better basic private properties and leads to exaggerated values on
privacy budgets. We propose Wasserstein differential privacy (WDP), an
alternative DP framework to measure the risk of privacy leakage, which
satisfies the properties of symmetry and triangle inequality. We show and prove
that WDP has 13 excellent properties, which can be theoretical supports for the
better performance of WDP than other DP frameworks. In addition, we derive a
general privacy accounting method called Wasserstein accountant, which enables
WDP to be applied in stochastic gradient descent (SGD) scenarios containing
sub-sampling. Experiments on basic mechanisms, compositions and deep learning
show that the privacy budgets obtained by Wasserstein accountant are relatively
stable and less influenced by order. Moreover, the overestimation on privacy
budgets can be effectively alleviated. The code is available at
https://github.com/Hifipsysta/WDP.Comment: Accepted by AAAI 202
ASXL1 interacts with the cohesin complex to maintain chromatid separation and gene expression for normal hematopoiesis
ASXL1 is frequently mutated in a spectrum of myeloid malignancies with poor prognosis. Loss of Asxl1 leads to myelodysplastic syndrome-like disease in mice; however, the underlying molecular mechanisms remain unclear. We report that ASXL1 interacts with the cohesin complex, which has been shown to guide sister chromatid segregation and regulate gene expression. Loss of Asxl1 impairs the cohesin function, as reflected by an impaired telophase chromatid disjunction in hematopoietic cells. Chromatin immunoprecipitation followed by DNA sequencing data revealed that ASXL1, RAD21, and SMC1A share 93% of genomic binding sites at promoter regions in Lin-cKit+ (LK) cells. We have shown that loss of Asxl1 reduces the genome binding of RAD21 and SMC1A and alters the expression of ASXL1/cohesin target genes in LK cells. Our study underscores the ASXL1-cohesin interaction as a novel means to maintain normal sister chromatid separation and regulate gene expression in hematopoietic cells
The Impact of Merkel Cell Polyomavirus Positivity on Prognosis of Merkel Cell Carcinoma: A Systematic Review and Meta-Analysis
INTRODUCTION: There are numerous findings over the past decade have indicated that Merkel cell carcinoma (MCC) may have two pathways of pathogenesis: one related to ultraviolet irradiation and the other to the Merkel cell polyomavirus (MCPyV). However, the predictive and clinicopathological value of MCPyV positivity in MCC patients is still debatable. This article aims to examine the most recent data regarding this issue.
METHODS: The thorough literature searches were conducted in the Medline Ovid, PubMed, Web of Science, the Cochrane CENTRAL Databases, and Embase Databases until December 31, 2021. The associations between overall survival (OS), Merkel cell carcinoma-specific survival (MSS), recurrence-free survival (RFS), progression-free survival (PFS), clinicopathologic features, and MCPyV positivity were examined in our meta-analysis.
RESULTS: This meta-analysis included a total of 14 studies involving 1595 patients. Our findings demonstrated a significant correlation between MCPyV positivity and improved OS (HR=0.61, 95%CI:0.39-0.94, P=0.026) and improved PFS (HR=0.61, 95% CI: 0.45-0.83, P=0.002). MCPyV positivity did not, however, appear to be associated with either MSS (HR=0.61, 95%CI: 0.28-1.32, P=0.209) or RFS (HR= 0.93, 95%CI: 0.37-2.34, P=0.873). Pooled results revealed a correlation between MCPyV positivity with gender (male vs. female, OR=0.606, 95%CI: 0.449-0.817, P=0.001), histopathological stage (AJCC I-II vs. III-IV, OR=1.636, 95%CI: 1.126-2.378, P=0.010) and primary site (head and neck vs. other sites, OR=0.409, 95%CI: 0.221-0.757, P=0.004).
CONCLUSION: These results imply that MCPyV positivity may present a promising predictive biomarker for human MCC and call for further study
Model and Evaluation: Towards Fairness in Multilingual Text Classification
Recently, more and more research has focused on addressing bias in text
classification models. However, existing research mainly focuses on the
fairness of monolingual text classification models, and research on fairness
for multilingual text classification is still very limited. In this paper, we
focus on the task of multilingual text classification and propose a debiasing
framework for multilingual text classification based on contrastive learning.
Our proposed method does not rely on any external language resources and can be
extended to any other languages. The model contains four modules: multilingual
text representation module, language fusion module, text debiasing module, and
text classification module. The multilingual text representation module uses a
multilingual pre-trained language model to represent the text, the language
fusion module makes the semantic spaces of different languages tend to be
consistent through contrastive learning, and the text debiasing module uses
contrastive learning to make the model unable to identify sensitive attributes'
information. The text classification module completes the basic tasks of
multilingual text classification. In addition, the existing research on the
fairness of multilingual text classification is relatively simple in the
evaluation mode. The evaluation method of fairness is the same as the
monolingual equality difference evaluation method, that is, the evaluation is
performed on a single language. We propose a multi-dimensional fairness
evaluation framework for multilingual text classification, which evaluates the
model's monolingual equality difference, multilingual equality difference,
multilingual equality performance difference, and destructiveness of the
fairness strategy. We hope that our work can provide a more general debiasing
method and a more comprehensive evaluation framework for multilingual text
fairness tasks
An Effective Deployment of Contrastive Learning in Multi-label Text Classification
The effectiveness of contrastive learning technology in natural language
processing tasks is yet to be explored and analyzed. How to construct positive
and negative samples correctly and reasonably is the core challenge of
contrastive learning. It is even harder to discover contrastive objects in
multi-label text classification tasks. There are very few contrastive losses
proposed previously. In this paper, we investigate the problem from a different
angle by proposing five novel contrastive losses for multi-label text
classification tasks. These are Strict Contrastive Loss (SCL), Intra-label
Contrastive Loss (ICL), Jaccard Similarity Contrastive Loss (JSCL), Jaccard
Similarity Probability Contrastive Loss (JSPCL), and Stepwise Label Contrastive
Loss (SLCL). We explore the effectiveness of contrastive learning for
multi-label text classification tasks by the employment of these novel losses
and provide a set of baseline models for deploying contrastive learning
techniques on specific tasks. We further perform an interpretable analysis of
our approach to show how different components of contrastive learning losses
play their roles. The experimental results show that our proposed contrastive
losses can bring improvement to multi-label text classification tasks. Our work
also explores how contrastive learning should be adapted for multi-label text
classification tasks.Comment: Accepted by ACL-Findings 2023, 13 page
CL-XABSA: Contrastive Learning for Cross-lingual Aspect-based Sentiment Analysis
As an extensive research in the field of Natural language processing (NLP),
aspect-based sentiment analysis (ABSA) is the task of predicting the sentiment
expressed in a text relative to the corresponding aspect. Unfortunately, most
languages lack of sufficient annotation resources, thus more and more recent
researchers focus on cross-lingual aspect-based sentiment analysis (XABSA).
However, most recent researches only concentrate on cross-lingual data
alignment instead of model alignment. To this end, we propose a novel
framework, CL-XABSA: Contrastive Learning for Cross-lingual Aspect-Based
Sentiment Analysis. Specifically, we design two contrastive strategies, token
level contrastive learning of token embeddings (TL-CTE) and sentiment level
contrastive learning of token embeddings (SL-CTE), to regularize the semantic
space of source and target language to be more uniform. Since our framework can
receive datasets in multiple languages during training, our framework can be
adapted not only for XABSA task, but also for multilingual aspect-based
sentiment analysis (MABSA). To further improve the performance of our model, we
perform knowledge distillation technology leveraging data from unlabeled target
language. In the distillation XABSA task, we further explore the comparative
effectiveness of different data (source dataset, translated dataset, and
code-switched dataset). The results demonstrate that the proposed method has a
certain improvement in the three tasks of XABSA, distillation XABSA and MABSA.
For reproducibility, our code for this paper is available at
https://github.com/GKLMIP/CL-XABSA
FlattenQuant: Breaking Through the Inference Compute-bound for Large Language Models with Per-tensor Quantization
Large language models (LLMs) have demonstrated state-of-the-art performance
across various tasks. However, the latency of inference and the large GPU
memory consumption of LLMs restrict their deployment performance. Recently,
there have been some efficient attempts to quantize LLMs, yet inference with
large batch size or long sequence still has the issue of being compute-bound.
Fine-grained quantization methods have showcased their proficiency in achieving
low-bit quantization for LLMs, while requiring FP16 data type for linear layer
computations, which is time-consuming when dealing with large batch size or
long sequence. In this paper, we introduce a method called FlattenQuant, which
significantly reduces the maximum value of the tensor by flattening the large
channels in the tensor, to achieve low bit per-tensor quantization with minimal
accuracy loss. Our experiments show that FlattenQuant can directly use 4 bits
to achieve 48.29% of the linear layer calculation in LLMs, with the remaining
layers using 8 bits. The 4-bit matrix multiplication introduced in the
FlattenQuant method can effectively address the compute-bound caused by large
matrix calculation. Our work achieves up to 2 speedup and 2.3
memory reduction for LLMs with negligible loss in accuracy
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