398 research outputs found
Effects of Body Composition on Weight-Bearing Staging in Firefighters: Based on Linear, PLS Regression Model Analysis
Firefighters are often exposed to traumatic events such as high temperatures, heavy fumes, and toxic gases during rescue services. The challenges require firefighters to have a higher level of physical performance compared to a typical person. In urbanized settings, weight-bearing staging is a necessary skill for firefighters. Currently, research has found a positive correlation between firefighter body composition and occupational activity performance. This study aims to examine effects of body composition on the weight-bearing staging performance of firefighters, providing guidance for firefighters\u27 daily training routines. Participants were 47 male firefighters in Yangjiang City, Guangdong Province (age: 25.2 Ā± 3.9; height: 169.8 Ā± 5.1cm; 68.9 Ā± 8.0kg; 24.2 Ā± 2.4kg / m2). Load climbing tests were organized by the fire rescue brigade in Yangjiang City. The tested wore a full set of fire protective clothing, carried a positive pressure air respirator and carried two water belts (with a total load of 30kg), climb to a 10-story building and record the test completion time by manual timing. For body compositions, body weight, body fat, skeletal muscle content and lean weight were measured by machine with the help of Inbody 360 body composition tester. Linear and PLS regressions were used for data analysis. In the Gray\u27s association degree analysis, the association degree of the weight indicators was ranked first, meaning that weight had the strongest association with weight-bearing indoor performance. In linear regression analysis, the model equation was derived as follows: weight-bearing floor performance (s) = 16.20 + 0.9056 * weight (kg), and the R-square of the model was 0.1927, implying that body weight could explain 19.27% of the variance in weight-bearing floor performance. An F-test of the linear model yielded F = 10.74, P \u3c 0.05. In the PLS regression analysis, the principal component of 1 was the optimal number of extractions from the projection importance index VIP value, and the final result was that the regression of weight and body fat on weight-bearing dengue performance had a significant effect. Based on the results, the highest association emerged between weight and weight-bearing performance; weight had a significant effect on the weight-bearing performance, with greater weight-bearing sitting time; weight and body fat had significant effects on weight-bearing staging performance. To maintain adequate occupational mobility, firefighters are recommended to manage body composition through aerobic endurance and strength training
Optical property of few-mode fiber with non-uniform refractive index for cylindrical vector beam generation
This paper investigates optical properties of few-mode fiber with non-uniform refractive index, namely: the few mode fiber with U-shape refractive index and the two-mode and four-mode few-mode fiber with bent radius. Finite element method is used to analyze the mode distributions based on their non-uniform refractive index. Effective mode control can be achieved through these few mode fibers to achieve vector beam generation. Finally, reflection spectra of a few-mode fiber Bragg grating are calculated theoretically and then measured under different bending conditions. Experimental results are in good accordance with the theoretical ones. These few mode fibers show potential applications in generation of cylindrical vector beam both for optical lasing and sensing systems
Experimental analysis of gene assembly with TopDown one-step real-time gene synthesis
Herein we present a simple, cost-effective TopDown (TD) gene synthesis method that eliminates the interference between the polymerase chain reactions (PCR) assembly and amplification in one-step gene synthesis. The method involves two key steps: (i) design of outer primers and assembly oligonucleotide set with a melting temperature difference of >10Ā°C and (ii) utilization of annealing temperatures to selectively control the efficiencies of oligonucleotide assembly and full-length template amplification. In addition, we have combined the proposed method with real-time PCR to analyze the step-wise efficiency and the kinetics of the gene synthesis process. Gel electrophoresis results are compared with real-time fluorescence signals to investigate the effects of oligonucleotide concentration, outer primer concentration, stringency of annealing temperature, and number of PCR cycles. Analysis of the experimental results has led to insights into the gene synthesis process. We further discuss the conditions for preventing the formation of spurious DNA products. The TD real-time gene synthesis method provides a simple and efficient method for assembling fairly long DNA sequence, and aids in optimizing gene synthesis conditions. To our knowledge, this is the first report that utilizes real-time PCR for gene synthesis
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Transcriptome profiling reveals the crucial biological pathways involved in cold response in Moso bamboo (Phyllostachys edulis).
Most bamboo species including Moso bamboo (Phyllostachys edulis) are tropical or subtropical plants that greatly contribute to human well-being. Low temperature is one of the main environmental factors restricting bamboo growth and geographic distribution. Our knowledge of the molecular changes during bamboo adaption to cold stress remains limited. Here, we provided a general overview of the cold-responsive transcriptional profiles in Moso bamboo by systematically analyzing its transcriptomic response under cold stress. Our results showed that low temperature induced strong morphological and biochemical alternations in Moso bamboo. To examine the global gene expression changes in response to cold, 12 libraries (non-treated, cold-treated 0.5, 1 and 24Ā h at -2 Ā°C) were sequenced using an Illumina sequencing platform. Only a few differentially expressed genes (DEGs) were identified at early stage, while a large number of DEGs were identified at late stage in this study, suggesting that the majority of cold response genes in bamboo are late-responsive genes. A total of 222 transcription factors from 24 different families were differentially expressed during 24-h cold treatment, and the expressions of several well-known C-repeat/dehydration responsive element-binding factor negative regulators were significantly upregulated in response to cold, indicating the existence of special cold response networks. Our data also revealed that the expression of genes related to cell wall and the biosynthesis of fatty acids were altered in response to cold stress, indicating their potential roles in the acquisition of bamboo cold tolerance. In summary, our studies showed that both plant kingdom-conserved and species-specific cold response pathways exist in Moso bamboo, which lays the foundation for studying the regulatory mechanisms underlying bamboo cold stress response and provides useful gene resources for the construction of cold-tolerant bamboo through genetic engineering in the future
Meta-augmented Prompt Tuning for Better Few-shot Learning
Prompt tuning is a parameter-efficient method, which freezes all PLM
parameters and only prepends some additional tunable tokens called soft prompts
to the input text. However, soft prompts heavily rely on a better
initialization and may easily result in overfitting under few-shot settings,
which causes prompt-tuning performing much worse than fine-tuning. To address
the above issues, this paper proposes a novel Self-sUpervised Meta-prompt
learning framework with MEtagradient Regularization for few shot generalization
(SUMMER). We leverage self-supervised meta-learning to better initialize soft
prompts and curriculum-based task augmentation is further proposed to enrich
the meta-task distribution. Besides, a novel meta-gradient regularization
method is integrated into the meta-prompt learning framework, which meta-learns
to transform the raw gradient during few-shot learning into a
domain-generalizable direction, thus alleviating the problem of overfitting.
Extensive experiments show that SUMMER achieves better performance for
different few-shot downstream tasks, and also exhibits a stronger domain
generalization ability
A superconducting wireless energiser based on electromechanical energy conversion
A superconducting magnet (SM) can produce high magnetic fields up to a dozen times stronger than those generated by an electromagnet made of normal conductors or a permanent magnet (PM), and thus has attracted increasing research efforts in many domains including medical devices, large scientific equipment, transport, energy storage, power systems, and electric machines. Wireless energisers, e.g., high temperature superconducting (HTS) flux pumps, can eliminate the thermal load from current leads and arc erosion of slip rings, and are thus considered a promising energisation tool for SMs. However, the time-averaged DC output voltage in existing HTS flux pumps is generated by dynamic resistance: the dynamic loss is unavoidable, and the total AC loss will become significant at high frequencies. This study introduces a highly efficient superconducting wireless energizer (SWE) designed specifically for SMs. The SWE takes advantage of the inherent properties of a superconducting loop, including flux conservation and zero DC resistivity. Extensive theoretical analysis, numerical modelling exploiting the H-Ļ formulation, and experimental measurements were conducted to demonstrate the efficiency and efficacy of the novel SWE design. The electromechanical performance and loss characteristics of the SWE system have also been investigated. Compared to conventional HTS flux pumps, the proposed SWE has lower excitation loss, in the order of 10ā1 mW, and thus can achieve a high system efficiency of no less than 95%. Furthermore, it has a simpler structure with higher reliability, considered ready for further industrial development. In addition to deepening the understating of the intricate electromechanical dynamics between magnetic dipoles and superconducting circuits, this article provides a novel wireless energisation technique for SMs and opens the way to step changes in future electric transport and energy sectors
An injection-locked single-longitudinal-mode fiber ring laser with cylindrical vector beam emission
We demonstrate a fiber ring laser with narrow bandwidth single-longitudinal-mode cylindrical vector beam (CVB) output at C-band wavelength range for the first time to the best of our knowledge. A step index two-mode fiber Bragg grating is used as a transverse mode selector for CVB generation, while both the injection-locking technique and narrow bandwidth of the fiber Bragg grating lead to single-longitudinal-mode operation. The 3-dB bandwidth of the laser output is measured to be 60 dB. Mode distribution and optical spectra of few-mode fibers with periodic modulated refractive index profile, namely the few-mode fiber Bragg gratings with bent radius, are investigated theoretically and experimentally, which provide a comprehensive exploration of CVB's generation
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