147 research outputs found
An Efficiency-Improved Tightly Coupled Dipole Reflectarray Antenna Using Variant-Coupling-Capacitance Method
In this paper, a tightly coupled dipole reflectarray antenna as well as a variant-coupling-capacitance method to improve the antenna aperture efficiency is presented. Tightly coupled elements and true-time-delay lines are employed in the design of a wideband reflectarray. The proposed reflectarray can operate from 2 GHz to 5 GHz with the gain varying from 11.3 dBi to 21 dBi. Moreover, we propose a variant-coupling-capacitance method to improve the reflectarray aperture efficiency at lower frequency. By changing the coupling capacitance between neighboring elements according to their positions in the reflecting surface, a more linear equivalent distance delay line is achieved. Hence, phase error is reduced. According to measurement, the reflectarray gain in 2 GHz using the proposed method is increased by 3 dBi compared with the previous design. Aperture efficiency in 2 GHz is improved by 21.6%
GraphPrompt: Biomedical Entity Normalization Using Graph-based Prompt Templates
Biomedical entity normalization unifies the language across biomedical
experiments and studies, and further enables us to obtain a holistic view of
life sciences. Current approaches mainly study the normalization of more
standardized entities such as diseases and drugs, while disregarding the more
ambiguous but crucial entities such as pathways, functions and cell types,
hindering their real-world applications. To achieve biomedical entity
normalization on these under-explored entities, we first introduce an
expert-curated dataset OBO-syn encompassing 70 different types of entities and
2 million curated entity-synonym pairs. To utilize the unique graph structure
in this dataset, we propose GraphPrompt, a prompt-based learning approach that
creates prompt templates according to the graphs. GraphPrompt obtained 41.0%
and 29.9% improvement on zero-shot and few-shot settings respectively,
indicating the effectiveness of these graph-based prompt templates. We envision
that our method GraphPrompt and OBO-syn dataset can be broadly applied to
graph-based NLP tasks, and serve as the basis for analyzing diverse and
accumulating biomedical data.Comment: 12 page
From Terahertz Imaging to Terahertz Wireless Communications
Terahertz (THz) technology is probably best known to the public as a powerful tool for imaging, since it has been applied in security and medical scanning, resulting in numerous impressive images that would be unobtainable using other technologies. With the roll-out of 5G mobile networks, research into 6G wireless communications is heating up. It is envisioned that THz technology will be used for 6G and future wireless communications. In this paper, we review how THz technology has been employed for imaging and wireless communications, identify state-of-the-art developments in the field, and then examine and compare common devices and issues in both applications. The possibility of integrating THz imaging/sensing and wireless communications is considered, and challenges and future perspectives are presented and discussed. It is shown that THz technology is indeed a key enabling technology for both imaging and wireless communications in the future
PromptAgent: Strategic Planning with Language Models Enables Expert-level Prompt Optimization
Highly effective, task-specific prompts are often heavily engineered by
experts to integrate detailed instructions and domain insights based on a deep
understanding of both instincts of large language models (LLMs) and the
intricacies of the target task. However, automating the generation of such
expert-level prompts remains elusive. Existing prompt optimization methods tend
to overlook the depth of domain knowledge and struggle to efficiently explore
the vast space of expert-level prompts. Addressing this, we present
PromptAgent, an optimization method that autonomously crafts prompts equivalent
in quality to those handcrafted by experts. At its core, PromptAgent views
prompt optimization as a strategic planning problem and employs a principled
planning algorithm, rooted in Monte Carlo tree search, to strategically
navigate the expert-level prompt space. Inspired by human-like trial-and-error
exploration, PromptAgent induces precise expert-level insights and in-depth
instructions by reflecting on model errors and generating constructive error
feedback. Such a novel framework allows the agent to iteratively examine
intermediate prompts (states), refine them based on error feedbacks (actions),
simulate future rewards, and search for high-reward paths leading to expert
prompts. We apply PromptAgent to 12 tasks spanning three practical domains:
BIG-Bench Hard (BBH), as well as domain-specific and general NLP tasks, showing
it significantly outperforms strong Chain-of-Thought and recent prompt
optimization baselines. Extensive analyses emphasize its capability to craft
expert-level, detailed, and domain-insightful prompts with great efficiency and
generalizability.Comment: 34 pages, 10 figure
Myloid cell-specific lipin-1 deficiency stimulates endocrine adiponectin-FGF15 axis and ameliorates ethanol-induced liver injury in mice
Lipin-1 is a phosphatidate phosphohydrolase (PAP) required for the generation of diacylglycerol during glycerolipid synthesis, and exhibits dual functions in the regulation of lipid metabolism. Lipin-1 has been implicated in the pathogenesis of alcoholic liver disease (ALD). In the present study, we assessed lipin-1 function in myeloid cells in ALD using a myeloid cell-specific lipin-1 knockout (mLipin-1KO) mouse model. Utilizing the Gao-binge ethanol feeding protocol, matched mLipin-1KO mice and littermate loxP control (WT) mice were pair-fed with either an ethanol-containing diet or an ethanol-free diet (control). Surprisingly, deletion of lipin-1 in myeloid cells dramatically attenuated liver inflammatory responses and ameliorated liver injury that would normally occur following the ethanol feeding protocol, but slightly exacerbated the ethanol-induced steatosis in mice. Mechanistically, myeloid cell-specific lipin-1 deficiency concomitantly increased the fat-derived adiponectin and ileum-derived fibroblast growth factor (FGF) 15. In concordance with concerted elevation of circulating adiponectin and FGF15, myeloid cell-specific lipin-1 deficiency diminished hepatic nuclear factor kappa B (NF-κB) activity, limited liver inflammatory responses, normalized serum levels of bile acids, and protected mice from liver damage after ethanol challenge. Our novel data demonstrate that myeloid cell-specific deletion of lipin-1 ameliorated inflammation and alcoholic hepatitis in mice via activation of endocrine adiponectin-FGF15 signaling
Genetic Relationships of Ethnic Minorities in Southwest China Revealed by Microsatellite Markers
Population migrations in Southwest and South China have played an important role in the formation of East Asian populations and led to a high degree of cultural diversity among ethnic minorities living in these areas. To explore the genetic relationships of these ethnic minorities, we systematically surveyed the variation of 10 autosomal STR markers of 1,538 individuals from 30 populations of 25 ethnic minorities, of which the majority were chosen from Southwest China, especially Yunnan Province. With genotyped data of the markers, we constructed phylogenies of these populations with both DA and DC measures and performed a principal component analysis, as well as a clustering analysis by structure. Results showed that we successfully recovered the genetic structure of analyzed populations formed by historical migrations. Aggregation patterns of these populations accord well with their linguistic affiliations, suggesting that deciphering of genetic relationships does in fact offer clues for study of ethnic differentiation
W-Band Cavity-backed Folded-slot Antenna Using GaAs Integrated Passive Device Technology
A W-band cavity-backed folded-slot antenna based on GaAs integrated passive device technology is proposed in this paper for the first time. A via-cavity is formed to produce TE120 mode resonance and suppress surface waves, and an offset folded slot is designed to match the high impedance of the cavity. The simulated and measured S11 and the simulated radiation patterns are presented, which demonstrate that the antenna can operate from 97.8 GHz to 98.6 GHz with a maximum gain of 2.5 dBi while consuming a small area of only 0.84 mm× 1.325 mm. The proposed antenna is suitable for system-on-chip millimeter-wave applications where front-end modules and the antenna are built on the same chip for minimal signal transfer loss
QTL-seq analysis identified the genomic regions of plant height and days to heading in high-latitude rice
Introduction: Rice (Oryza sativa L.) is one of the most extensive crops in the world. China’s Heilongjiang Province is the northernmost rice-growing region in the world. However, rice cultivars suitable for growth in low-latitude regions may not mature normally due to their distinct climate and short frost-free period. It is necessary to precisely determine the frost-free period for each region to make the best use of the rice growth stage so as to ensure the maturity and yield of different rice cultivars in Heilongjiang Province. The time span of the heading stage is a key parameter for evaluating the adaptability of a rice cultivar to a specific rice-growing region. Given the above facts, it is of high importance to study the associated genes and sites controlling days to heading (DH) and plant height (PH) of rice in Heilongjiang Province. Bulked segregant analysis (BSA) combined with high-throughput sequencing can effectively exclude interferences from background genomic differences, making it suitable for analyzing the associated sites of complex agronomic traits in early generations.Methods: In this study, an F3 segregating population was obtained by crossing two main cultivars that are grown under different temperatures and day-light conditions in Heilongjiang. Two pools of extreme phenotypes were built for the DH and PH of the population. For SNP and InDel variants obtained from whole-genome resequencing in the pools, an association analysis was performed using the Euclidean distance (ED) algorithm and the SNP/InDel index algorithm.Results: The intersection of SNP and InDel regions associated with the phenotypes was considered to obtain the final associated sites. After excluding interferences from the cloned genes on chromosomes 2 and 7, a total length of 6.34 Mb on chromosomes 1, 3, and 10 and 3.16 Mb on chromosomes 1 and 10 were left associated with PH and DH, respectively. Then, we performed a gene annotation analysis for candidate genes in the remaining regions using multiple genome annotation databases. Our research provides basic data for subsequent gene mapping and cloning.Discussion: By mining more genetic loci associated with the days to heading and plant height of rice, we may provide abundant genetic resources for refined molecular breeding in Heilongjiang Province
Crop Diversity for Yield Increase
Traditional farming practices suggest that cultivation of a mixture of crop species in the same field through temporal and spatial management may be advantageous in boosting yields and preventing disease, but evidence from large-scale field testing is limited. Increasing crop diversity through intercropping addresses the problem of increasing land utilization and crop productivity. In collaboration with farmers and extension personnel, we tested intercropping of tobacco, maize, sugarcane, potato, wheat and broad bean – either by relay cropping or by mixing crop species based on differences in their heights, and practiced these patterns on 15,302 hectares in ten counties in Yunnan Province, China. The results of observation plots within these areas showed that some combinations increased crop yields for the same season between 33.2 and 84.7% and reached a land equivalent ratio (LER) of between 1.31 and 1.84. This approach can be easily applied in developing countries, which is crucial in face of dwindling arable land and increasing food demand
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