368 research outputs found
Global exponential stability of impulsive dynamical systems with distributed delays
In this paper, the global exponential stability of dynamical systems with distributed delays and impulsive effect is investigated. By establishing an impulsive differential-integro inequality, we obtain some sufficient conditions ensuring the global exponential stability of the dynamical system. Three examples are given to illustrate the effectiveness of our theoretical results
Applications of Wavelet Transforms in Biomedical Optoacoustics
We discuss the utility of wavelet transform methods in signal processing in general, and in particular, demonstrate the technique in optoacoustic applications. In several optoacoustic experiments with different samples, we have successfully enhanced the signal to noise ratios. Wavelet transforms optimize resolution by utilizing a tailored, variable time-window in different frequency regions. The technique\u27s great advantage lies in the fact that the wavelet transform adds some redundancy to the original signal, and some desired features can be enhanced in the transformed space. In addition, proper choice of the basis set allows a sparse representation of the signal. Therefore, even when some components are suppressed in the transformed space, the signal itself can maintain its fidelity. This technique has great potential in biomedical optoacoustics, such as medical image processing and signal denoising. We use the wavelet transform technique to resolve acoustic echoes in the time-dilation space. White noise was removed by the wavelet shrinkage method. This processing was used to analyze several experimental results. These include optoacoustic measurements in solid samples as well as in biological tissues
Early selection of \u3cem\u3ebZIP73\u3c/em\u3e facilitated adaptation of \u3cem\u3ejaponica\u3c/em\u3e rice to cold climates
Cold stress is a major factor limiting production and geographic distribution of rice (Oryza sativa). Although the growth range of japonica subspecies has expanded northward compared to modern wild rice (O. rufipogon), the molecular basis of the adaptation remains unclear. Here we report bZIP73, a bZIP transcription factor-coding gene with only one functional polymorphism (+511 G\u3eA) between the two subspecies japonica and indica, may have facilitated japonica adaptation to cold climates. We show the japonica version of bZIP73 (bZIP73Jap) interacts with bZIP71 and modulates ABA levels and ROS homeostasis. Evolutionary and population genetic analyses suggest bZIP73 has undergone balancing selection; the bZIP73Jap allele has firstly selected from standing variations in wild rice and likely facilitated cold climate adaptation during initial japonica domestication, while the indica allele bZIP73Ind was subsequently selected for reasons that remain unclear. Our findings reveal early selection of bZIP73Jap may have facilitated climate adaptation of primitive rice germplasms
A Pseudo DNA Cryptography Method
The DNA cryptography is a new and very promising direction in cryptography
research. DNA can be used in cryptography for storing and transmitting the
information, as well as for computation. Although in its primitive stage, DNA
cryptography is shown to be very effective. Currently, several DNA computing
algorithms are proposed for quite some cryptography, cryptanalysis and
steganography problems, and they are very powerful in these areas. However, the
use of the DNA as a means of cryptography has high tech lab requirements and
computational limitations, as well as the labor intensive extrapolation means
so far. These make the efficient use of DNA cryptography difficult in the
security world now. Therefore, more theoretical analysis should be performed
before its real applications.
In this project, We do not intended to utilize real DNA to perform the
cryptography process; rather, We will introduce a new cryptography method based
on central dogma of molecular biology. Since this method simulates some
critical processes in central dogma, it is a pseudo DNA cryptography method.
The theoretical analysis and experiments show this method to be efficient in
computation, storage and transmission; and it is very powerful against certain
attacks. Thus, this method can be of many uses in cryptography, such as an
enhancement insecurity and speed to the other cryptography methods. There are
also extensions and variations to this method, which have enhanced security,
effectiveness and applicability.Comment: A small work that quite some people asked abou
DISC-LawLLM: Fine-tuning Large Language Models for Intelligent Legal Services
We propose DISC-LawLLM, an intelligent legal system utilizing large language
models (LLMs) to provide a wide range of legal services. We adopt legal
syllogism prompting strategies to construct supervised fine-tuning datasets in
the Chinese Judicial domain and fine-tune LLMs with legal reasoning capability.
We augment LLMs with a retrieval module to enhance models' ability to access
and utilize external legal knowledge. A comprehensive legal benchmark,
DISC-Law-Eval, is presented to evaluate intelligent legal systems from both
objective and subjective dimensions. Quantitative and qualitative results on
DISC-Law-Eval demonstrate the effectiveness of our system in serving various
users across diverse legal scenarios. The detailed resources are available at
https://github.com/FudanDISC/DISC-LawLLM
Reliable Detection of Myocardial Ischemia Using Machine Learning Based on Temporal-Spatial Characteristics of Electrocardiogram and Vectorcardiogram
Background: Myocardial ischemia is a common early symptom of cardiovascular disease (CVD). Reliable detection of myocardial ischemia using computer-aided analysis of electrocardiograms (ECG) provides an important reference for early diagnosis of CVD. The vectorcardiogram (VCG) could improve the performance of ECG-based myocardial ischemia detection by affording temporal-spatial characteristics related to myocardial ischemia and capturing subtle changes in ST-T segment in continuous cardiac cycles. We aim to investigate if the combination of ECG and VCG could improve the performance of machine learning algorithms in automatic myocardial ischemia detection. Methods: The ST-T segments of 20-second, 12-lead ECGs, and VCGs were extracted from 377 patients with myocardial ischemia and 52 healthy controls. Then, sample entropy (SampEn, of 12 ECG leads and of three VCG leads), spatial heterogeneity index (SHI, of VCG) and temporal heterogeneity index (THI, of VCG) are calculated. Using a grid search, four SampEn and two features are selected as input signal features for ECG-only and VCG-only models based on support vector machine (SVM), respectively. Similarly, three features (S ( I ), THI, and SHI, where S ( I ) is the SampEn of lead I) are further selected for the ECG + VCG model. 5-fold cross validation was used to assess the performance of ECG-only, VCG-only, and ECG + VCG models. To fully evaluate the algorithmic generalization ability, the model with the best performance was selected and tested on a third independent dataset of 148 patients with myocardial ischemia and 52 healthy controls. Results: The ECG + VCG model with three features (S ( I ),THI, and SHI) yields better classifying results than ECG-only and VCG-only models with the average accuracy of 0.903, sensitivity of 0.903, specificity of 0.905, F1 score of 0.942, and AUC of 0.904, which shows better performance with fewer features compared with existing works. On the third independent dataset, the testing showed an AUC of 0.814. Conclusion: The SVM algorithm based on the ECG + VCG model could reliably detect myocardial ischemia, providing a potential tool to assist cardiologists in the early diagnosis of CVD in routine screening during primary care services
Bio-inspirations for the Development of Light Materials based on the Nanomechanical Properties and Microstructures of Beetle Dynastes tityus
Dynastes tityus (D. tityus) is a typical beetle whose elytra are light and strong. The primary function of elytra is to protect beetle’s
hindwings. In this paper, D. tityus elytra were selected as the biological prototype for the investigation to obtain bio-inspirations for the
design and development of light materials with high ratio of strength to mass. Firstly, the microstructure investigation and quasi-static
nanoindentation tests have been carried out on the ten samples of the selected elytra of D. tityus to reveal their mechanical properties and
microstructures. Secondly, based on the findings from the microstructure investigation and nanoindentation tests, three models of
bio-inspired materials have been proposed for further study to gain the deep understanding of the relationships between the special mechanical
characteristics and microstructures. Then Finite Element Analysis (FEA) simulations have been performed on the three models
for harvesting the bio-inspirations for the initial design of light materials. Finally, through comparative analysis of the findings from the
microstructure investigation, the nanoindentation tests and the simulations, some meaningful bio-inspirations have been reaped for the
future optimization of the design and development of light materials with high ratio of strength to mass
Distribution and conservation status of Camellia longzhouensis (Theaceae), a critically endangered plant species endemic to southern China
Camellia longzhouensis (Theaceae) is an endemic evergreen shrub or small tree with a distribution restricted to South China. It is listed as Grade-II in the National Key Protected Wild Plants List. In this study, we surveyed its distribution, examined its population structure, identified factors affecting its survival, and reassessed its extinction risk. We found that C. longzhouensis was only distributed in the Nonggang National Nature Reserve and the surrounding area. Its individuals only grew under the secondary forest canopy in the karst mountain. A total of 58 individuals of C. longzhouensis in three sub-populations were found. Soil fertility and understory light availability were the main habitat factors influencing the survival of C. longzhouensis. Anthropogenic disturbances and reproductive obstacles have caused a low seed-setting rate, poor seedling survival, and a lack of adult plants of C. longzhouensis in the natural habitat. The population structure of C. longzhouensis is spindle-shaped, indicating poor natural regeneration and inhibited seedling recruitment. Cleistanthus petelotii had a significant positive interspecific interaction with C. longzhouensis in the community. Based on the information obtained here and IUCN criterion C2ai, we recommend that C. longzhouensis be categorized in the International Union for Conservation of Nature (IUCN) Red List as Critically Endangered. We also developed a comprehensive protection strategy, consisting of in situ conservation, ex situ conservation, reintroduction, and commercial utilization. This strategy can be readily applied to protect other endangered plants with economic value in karst poor regions
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