44 research outputs found
Distribution of Three Congeneric Shrub Species Along an Aridity Gradient Is Related to Seed Germination and Seedling Emergence
Environmental tolerance of a species has been shown to correlate positively with its geographical range. On the Ordos Plateau, three Caragana species are distributed sequentially along the precipitation gradient. We hypothesized that this geographical distribution pattern is related to environmental tolerances of the three Caragana species during seed germination and seedling emergence stages. To test this hypothesis, we examined seed germination under different temperature, light and water potentials, and monitored seedling emergence for seeds buried at eight sand depths and given different amounts of water. Seeds of C. korshinskii germinated to high percentages at 5 : 15 to 25 : 35 °C in both light and darkness, while those of C. intermedia and C. microphylla did so only at 15 : 25 and 25 : 35 °C, respectively. Nearly 30 % of the C. korshinskii seeds germinated at -1.4 MPa at 20 and 25 °C, while no seeds of the other two species did so. Under the same treatments, seedling emergence percentages of C. korshinskii were higher than those of the other two species. The rank order of tolerance to drought and sand burial of the three species is C. korshinskii \u3e C. intermedia \u3e C. microphylla. The amount of precipitation and sand burial depth appear to be the main selective forces responsible for the geographical distribution of these species
LC–MS-Based Urine Metabolomics Analysis for the Diagnosis and Monitoring of Medulloblastoma
Medulloblastoma (MB) is the most common type of brain cancer in pediatric patients. Body fluid biomarkers will be helpful for clinical diagnosis and treatment. In this study, liquid chromatography–mass spectrometry (LC–MS)-based metabolomics was used to identify specific urine metabolites of MB in a cohort, including 118 healthy controls, 111 MB patients, 31 patients with malignant brain cancer, 51 patients with benign brain disease, 29 MB patients 1 week postsurgery and 80 MB patients 1 month postsurgery. The results showed an apparent separation for MB vs. healthy controls, MB vs. benign brain diseases, and MB vs. other malignant brain tumors, with AUCs values of 0.947/0.906, 0.900/0.873, and 0.842/0.885, respectively, in the discovery/validation group. Among all differentially identified metabolites, 4 metabolites (tetrahydrocortisone, cortolone, urothion and 20-oxo-leukotriene E4) were specific to MB. The analysis of these 4 metabolites in pre- and postoperative MB urine samples showed that their levels returned to a healthy state after the operation (especially after one month), showing the potential specificity of these metabolites for MB. Finally, the combination of two metabolites, tetrahydrocortisone and cortolone, showed diagnostic accuracy for distinguishing MB from non-MB, with an AUC value of 0.851. Our data showed that urine metabolomics might be used for MB diagnosis and monitoring
DeepSeek LLM: Scaling Open-Source Language Models with Longtermism
The rapid development of open-source large language models (LLMs) has been
truly remarkable. However, the scaling law described in previous literature
presents varying conclusions, which casts a dark cloud over scaling LLMs. We
delve into the study of scaling laws and present our distinctive findings that
facilitate scaling of large scale models in two commonly used open-source
configurations, 7B and 67B. Guided by the scaling laws, we introduce DeepSeek
LLM, a project dedicated to advancing open-source language models with a
long-term perspective. To support the pre-training phase, we have developed a
dataset that currently consists of 2 trillion tokens and is continuously
expanding. We further conduct supervised fine-tuning (SFT) and Direct
Preference Optimization (DPO) on DeepSeek LLM Base models, resulting in the
creation of DeepSeek Chat models. Our evaluation results demonstrate that
DeepSeek LLM 67B surpasses LLaMA-2 70B on various benchmarks, particularly in
the domains of code, mathematics, and reasoning. Furthermore, open-ended
evaluations reveal that DeepSeek LLM 67B Chat exhibits superior performance
compared to GPT-3.5
A Tourist Behavior Analysis Framework Guided by Geo-Information Tupu Theory and Its Application in Dengfeng City, China
With the development of tourism and the change in urban functions, the analysis of the spatial pattern of urban tourist flows has become increasingly important. Existing studies have explored and analyzed tourist behavior well, using the appropriate digital footprint data and research methods. However, most studies have ignored internal mechanisms analysis and tourism decision making. This paper proposed a novel framework for tourist behavior analysis inspired by geo-information Tupu, including three modules of the spatiotemporal database, symptom, diagnosis, and implementation. The spatiotemporal database module is mainly used for data acquisition and data cleaning of the digital footprint of tourists. The symptom module is mainly used for revealing the spatial patterns and network structures of tourist flows. The diagnosis and implementation module is mainly used for internal mechanism analysis and tourism decision making under different tourist flow patterns. This paper applied the proposed research framework to Dengfeng City, China, using online travel diaries as the source of digital footprint data, to analyze its tourist behavior. The results were as follows: tourist flows of Dengfeng were unevenly distributed, thus forming an obvious core–periphery structure with intense internal competition and unbalanced power. The difference in tourism resources between its northern and southern areas remains a challenge for future tourism development in Dengfeng
Safety and efficacy of indocyanine green fluorescence imaging for real-time guidance of laparoscopic thermal ablation in patients with liver cancer
AbstractPurpose To evaluate the safety and efficacy of indocyanine green fluorescence imaging for real-time guidance of laparoscopic thermal ablation in patients with liver cancer.Materials and methods A total of 27 patients with 40 liver lesions underwent fluorescence-assisted laparoscopic ablation between January 2020 to March 2023. The sensitivity of indocyanine green (ICG)-fluorescence imaging, technique effectiveness rate and complications of fluorescence-assisted laparoscopic thermal ablation were evaluated.Results In total, 33 out of the 40 lesions were identified by ICG-fluorescence imaging technique, with the sensitivity of 82.5%. The sensitivity of ICG-fluorescence imaging of tumor detection in liver surface of parenchyma was significantly higher than that in the deeply located hepatic parenchyma (96.8% vs 33.3%, p = 0.002). ICG-fluorescence imaging procedures detected 4 lesions that cannot be seen on intraoperative ultrasound. It provides clear demarcation lines on the hepatic surface. Technical success is achieved if the necrotic zone had at least a 5 mm ablative margin around the outer edge of the ICG-fluorescence image. Technical success of fluorescence laparoscopic radiofrequency ablation (FLRFA) and fluorescence laparoscopic microwave ablation (FLMWA) was 100% (27/27). Technical effectiveness is defined by the complete necrotic lesions of the local tumor tissue during follow-up. According to the CT/MRI one month after FLRFA or FLMWA, the technical efficacy rate was 92.5% (37/40) and local tumor progression occurred in 7.5% (3/40) of the enrolled lesions. During the follow-up period, no major complications were observed.Conclusion ICG-fluorescence imaging guided laparoscopic thermal ablation was feasible, safe and effective
Thermodynamic Calculation and Analysis of Equilibrium Precipitated Phases in Mar-M247 Superalloy
Effects of alloying elements on the equilibrium precipitated phases, incipient and final melting temperature of Mar-M247 superalloy were studied through thermodynamic calculation. The results show that the main phases are Îł' precipitates, MC, M6C, M23C6 carbides, ÎĽ phases, MB2 and M3B2 borides. Hf and Ta segregate more seriously mostly during solidification process. Around the composition range, Cr, Mo, Ti and Hf influence the initial melting temperature mostly. Precipitation temperature and precipitation amount of carbides increase linearly with the increase of the C content. Furthermore, Hf, Ti and Ta are contributed to the precipitation of MC carbides, Cr improves the precipitation of M23C6 and W and Mo are beneficial to the precipitation of M6C. The precipitation of ÎĽ phase is mainly influenced by Mo and W, the precipitation temperature and mass fraction of ÎĽ phase increase as the content of Mo and W increase. The precipitation behavior of Îł' phase is affected by Al, Ti and Ta contents, and their effects decrease in turn
Analysis of Tourist Market Structure and Its Driving Factors in Small Cities before and after COVID-19
Based on the digital footprint data, exploring the differences in tourist market structure and driving factors before and after COVID-19 is important for identifying tourist market demand and optimizing tourism product supply in the post-pandemic era. Most of the existing studies have explored the impact of the pandemic on the tourist market in well-known or large cities and have provided suggestions for tourism recovery. However, these suggestions are not entirely applicable to smaller cities. Small cities have a single level of tourism product, high homogeneity of tourism resources, small tourist market scale, and high volatility of the tourism industry. Therefore, it is necessary to study the differences in the tourist market structure of small cities and its driving factors before and after the pandemic and to propose targeted measures for the tourism recovery in the post-pandemic period. This paper, taking small cities as the study area and using online travel diaries as the data source, analyzed the differences in the spatial and temporal structures of tourist markets and their driving factors in Dengfeng and Kaifeng, China, before and after the pandemic. Then, countermeasures for tourism industry recovery in the post-pandemic era were proposed. The results were as follows: the difference in the tourism off-peak season increased after the pandemic, and the concentration of tourist market spatial distribution in Dengfeng showed a decreasing trend while that in Kaifeng showed an increasing trend. In addition to region traffic, the driving effects of leisure time, climate comfort and residents’ income level weakened after the outbreak. Dengfeng and Kaifeng can enhance the tourist market tendency and attractiveness by creating special indoor tourism projects, strengthening tourism product promotion and marketing and enhancing the facilities related to self-driving tours