RESUMEN
Nitrogen (N) deposition has increased dramatically in recent decades, which is significantly affecting the invasion and growth of exotic plants. Whether N deposition leads to invasive alien species becoming competitively superior to native species remains to be investigated. In the present study, an invasive species (Oenothera biennis L.) and three co-occurring native species (Artemisia argyi Lévl. et Vant., Inula japonica Thunb., and Chenopodium album L.) were grown in a monoculture (two seedlings of the same species) or mixed culture (one seedling of O. biennis and one seedling of a native species) under three levels of N deposition (0, 6, and 12 gâm-2âyear-1). Nitrogen deposition had no effect on soil N and P content. Nitrogen deposition enhanced the crown area, total biomass, leaf chlorophyll content, and leaf N to phosphorus ratio in both invasive and native plants. Oenothera biennis dominated competition with C. album and I. japonica due to its high resource acquisition and absorption capacity (greater height, canopy, leaf chlorophyll a to chlorophyll b ratio, leaf chlorophyll content, leaf N content, leaf mass fraction, and lower root-to-shoot ratio). However, the native species A. argyi exhibited competitive ability similar to O. biennis. Thus, invasive species are not always superior competitors of native species; this depends on the identities of the native species. High N deposition enhanced the competitive dominance of O. biennis over I. japonica by 15.45% but did not alter the competitive dominance of O. biennis over C. album. Furthermore, N deposition did not affect the dominance of O. biennis or A. argyi. Therefore, the species composition of the native community must be considered when preparing to resist future biological invasions. Our study contributes to a better understanding of the invasion mechanisms of alien species under N-loading conditions.
Asunto(s)
Nitrógeno , Plantas , Clorofila A , Plantones , Clorofila , Especies Introducidas , SueloRESUMEN
Coronary heart disease preoperative diagnosis plays an important role in the treatment of vascular interventional surgery. Actually, most doctors are used to diagnosing the position of the vascular stenosis and then empirically estimating vascular stenosis by selective coronary angiography images instead of using mouse, keyboard and computer during preoperative diagnosis. The invasive diagnostic modality is short of intuitive and natural interaction and the results are not accurate enough. Aiming at above problems, the coronary heart disease preoperative gesture interactive diagnostic system based on Augmented Reality is proposed. The system uses Leap Motion Controller to capture hand gesture video sequences and extract the features which that are the position and orientation vector of the gesture motion trajectory and the change of the hand shape. The training planet is determined by K-means algorithm and then the effect of gesture training is improved by multi-features and multi-observation sequences for gesture training. The reusability of gesture is improved by establishing the state transition model. The algorithm efficiency is improved by gesture prejudgment which is used by threshold discriminating before recognition. The integrity of the trajectory is preserved and the gesture motion space is extended by employing space rotation transformation of gesture manipulation plane. Ultimately, the gesture recognition based on SRT-HMM is realized. The diagnosis and measurement of the vascular stenosis are intuitively and naturally realized by operating and measuring the coronary artery model with augmented reality and gesture interaction techniques. All of the gesture recognition experiments show the distinguish ability and generalization ability of the algorithm and gesture interaction experiments prove the availability and reliability of the system.
Asunto(s)
Enfermedad Coronaria , Gestos , Algoritmos , Mano , Humanos , Reproducibilidad de los ResultadosRESUMEN
The aim of this study was to investigate the relationship between green biomass composition and thermal environment, as well as their optimal composition pattern. We decomposed total green biomass in a certain spatial range into two categories: trees and shrubs-grasses, with urban residential areas as sampling sites and based on aerial photography and field research data of green biomass and optimized green biomass measurement method. We analyzed the correlation between the green biomass composition indicators (shrub and grass biomass, tree canopy biomass, green biomass, mean tree canopy biomass, number of trees) and ambient temperature and humidity in different spatial ranges. The results showed that the most significant cooling and humidifying effect of different green biomass composition indicators was at 50 m below the building scale. The mean tree canopy biomass and tree canopy biomass were the key factors affecting ambient temperature and humidity, respectively, in different time periods during the day. With an average canopy biomass of about 211 m3 and 62 trees in a 50 m space, the regulation effects of trees on ambient temperature and humidity were closer to the thermal comfort requirements of human body.
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Frío , Fotograbar , Humanos , Biomasa , Estaciones del Año , Humedad , Poaceae , ÁrbolesRESUMEN
OBJECTIVES: Variceal hemorrhage is a fatal complication of cirrhosis. In this study, we aimed to investigate the role of serum interleukin 2 receptor (sIL-2R) as a predictive indicator in patients with a previous history of cirrhosis-related variceal bleeding. METHODS: A total of 340 cirrhotic patients who had experienced variceal bleeding from December 2016 to December 2018 were enrolled, and were randomly assigned to the modeling group and the validation group. The 3-year variceal rebleeding rate and other outcomes including adverse events were analyzed between patients with different sIL-2R levels. RESULTS: A time-dependent receiver operating characteristic (ROC) curve of variceal rebleeding indicated that sIL-2R had an area under the ROC curve (AUROC] of 0.731 and 0.837 for the modeling and validation groups, respectively, with a cut-off value of 426 U/mL. Kaplan-Meier analysis showed that higher sIL-2R level was related to an increased risk of variceal rebleeding rate (55.33% vs 24.34%, P = 0.024 and 51.28% vs 15.32%, P = 0.049) and decreased 3-year survival rate (91.16% vs 98.92%, P = 0.013 and 90.52% vs 97.50%, P = 0.180) in the modeling and validation groups. Elevated sIL-2R levels were associated with an increased risk of portal vein thrombosis and severe ascites as well as inferior liver function, hypercoagulable state, and increased portal pressure. CONCLUSION: High sIL-2R levels were associated with poor prognosis in cirrhotic patients with previous variceal bleeding.
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Várices Esofágicas y Gástricas , Humanos , Pronóstico , Várices Esofágicas y Gástricas/complicaciones , Hemorragia Gastrointestinal , Cirrosis Hepática/complicaciones , Receptores de Interleucina-2RESUMEN
OBJECTIVES: Gastric varices (GV), a common complication of liver cirrhosis, often cause serious consequences. However, the management of GV remains debated. In this study we aimed to explore the practice patterns of Chinese practitioners in GV treatment and discuss whether these patterns conform to the guidelines in China and around the world. METHODS: Between October 2020 and January 2021, an online questionnaire was sent to doctors from different regions in China via WeChat. Data on the practice patterns for endoscopic treatment with and without a multidisciplinary discussion team (MDT) clinic for GV were analyzed. RESULTS: Questionnaires were collected from 241 practitioners from 29 provinces in China. Before endoscopic treatment, 100 (41.5%) of the practitioners arranged computed tomography angiography (CTA) examination. In endoscopic tissue adhesive (ETA) treatment, 183 (75.9%) of the practitioners chose ETA combined with lauromacrogol. Approximately one-fourth of all practitioners did not prescribe drugs to reduce portal pressure. Only 75 (31.1%) of physicians preferred using early transjugular intrahepatic portosystemic shunt (TIPS) for patients at a high risk of treatment failure for GV. Compared to those without MDT clinics, practitioners with MDT clinics more often chose early TIPS for high-risk patients (39.0% vs 18.9%, P = 0.001). CONCLUSIONS: Treatment for GV differ across China. Practitioners with MDT clinics can better use assistant strategies such as CTA to evaluate the risk and efficacy. Further clinical studies are needed, and more guidelines and consensuses are warranted to standardize clinical practice for GV.
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Várices Esofágicas y Gástricas , Derivación Portosistémica Intrahepática Transyugular , Adhesivos Tisulares , Várices Esofágicas y Gástricas/etiología , Várices Esofágicas y Gástricas/cirugía , Hemorragia Gastrointestinal/etiología , Humanos , Presión Portal , Derivación Portosistémica Intrahepática Transyugular/efectos adversos , Encuestas y Cuestionarios , Adhesivos Tisulares/uso terapéutico , Resultado del TratamientoRESUMEN
Previous studies suggested an association between the EGF +61 A>G polymorphism and susceptibility to gastric cancer, but the results have been inconsistent. To draw a more precise risk estimation of the association, we performed a meta-analysis of published studies. PubMed, EMBASE, Google Scholar and the Chinese Wanfang databases were systematically searched to identify relevant studies. There were 7 studies involving 1992 cases of gastric cancer and 3202 controls in this meta-analysis. Our study showed that, overall, the EGF +61 A>G polymorphism was significantly associated with the increased risk of gastric cancer in allele model (G vs. A: OR=1.18, 95% CI=1.00-1.39), dominant model (GG + GA vs. AA: OR=1.28, 95% CI=1.05-1.55), homozygous model (GG vs. AA: OR=1.31, 95% CI=1.06-1.63) and heterozygous model (GA vs. AA: OR=1.25, 95% CI=1.01-1.53). The stratified analysis by ethnicity revealed a significant association between EGF +61 A>G polymorphism and gastric cancer risks in Asians. This meta-analysis indicates that EGF +61 A>G polymorphism may increase the risk of gastric cancer, especially in Asians. Large-sized, well-designed studies involving different ethnic groups should be conducted to confirm this association.