Competing risk model to determine the prognostic factors and treatment strategies for elderly patients with glioblastoma.

The prognostic factors and optimal treatment for the elderly patient with glioblastoma (GBM) were poorly understood. This study extracted 4975 elderly patients (≥ 65 years old) with histologically confirmed GBM from Surveillance, Epidemiology and End Results (SEER) database. Firstly, Cumulative incidence function and cox proportional model were utilized to illustrate the interference of non-GBM related mortality in our cohort. Then, the Fine-Gray competing risk model was applied to determine the prognostic factors for GBM related mortality. Age ≥ 75 years old, white race, size > 5.4 cm, frontal lobe tumor, and overlapping lesion were independently associated with more GBM related death, while Gross total resection (GTR) (HR 0.87, 95%CI 0.80-0.94, P = 0.010), radiotherapy (HR 0.64, 95%CI 0.55-0.74, P < 0.001), chemotherapy (HR 0.72, 95%CI 0.59-0.90, P = 0.003), and chemoRT (HR 0.43, 95%CI 0.38-0.48, P < 0.001) were identified as independently protective factors of GBM related death. Based on this, a corresponding nomogram was conducted to predict 3-, 6- and 12-month GBM related mortality, the C-index of which were 0.763, 0.718, and 0.694 respectively. The calibration curve showed that there was a good consistency between the predicted and the actual mortality probability. Concerning treatment options, GTR followed by chemoRT is suggested as optimal treatment. Radiotherapy and chemotherapy alone also provide moderate clinical benefits.

[Effects of nitrogen supplementation on forage yield and quality of a degraded grassland in Hulunbuir, China.] / æ°®ç´ è¡¥ç»™å¯¹å‘¼ä¼¦è´å°”è‰ç”¸è‰åŽŸé€€åŒ–è‰åœ°ç‰§è‰äº§é‡å’Œå“è´¨çš„å½±å“.

Long-term overuse of grasslands results in quantitative and qualitative decline of forage yield. Nutrient supplementation is a key strategy to improve forage yield. While mounting evidence showed that nitrogen (N) supplementation can increase forage yield, little is known about its impacts on forage quality. To understand the effects of N supplementation on forage quality at the community level, we carried out a field experiment in the meadow steppe of Hulunbuir. Our results showed that N supplementation significantly increased forage yield by 23%, which was mainly due to positive responses of perennial rhizomatous grass. The yield of other plant functional groups showed neutral response to N supplementation. The concentrations of crude protein, crude fat, and crude fiber varied significantly among different plant functional groups. Nitrogen supplementation significantly enhanced the concentration of crude protein in rhizomatous grass, bunchgrass, legume, and sedge. It enhanced the content of crude fat in rhizomatous grass but with no effect on other functional groups. Nitrogen supplementation had no effect on the concentration of crude fibre in all functional groups. At the community level, N supplementation significantly increased the concentrations of crude protein and crude fat. Our results are important for understanding the responses of forage production in meadow steppe under the scenarios of N enrichment.

Correction to: Mowing mitigates the negative impacts of N addition on plant species diversity.

Unfortunately, the panels of (f) in Figures 1, 2, and 4.

The relative contributions of intra- and inter-specific variation in driving community stoichiometric responses to nitrogen deposition and mowing in a grassland.

AIMS: The stoichiometric characteristics of plant communities are important controller for several fundamental ecological processes. The effects of environmental changes on community stoichiometric characteristics are driven by intra- and inter-specific variation. However, the relative importance of both pathways has seldom been empirically examined. METHODS: We quantified the relative contribution of intra- and inter-specific variation to the changes of community nitrogen (N) and phosphorus (P) concentrations after seven-year factorial N addition and mowing treatments in a semi-arid grassland of northern China. RESULTS: Nitrogen addition significantly increased community N and P concentrations and N:P ratio. Mowing significantly increased community N concentration and N:P. Intra-specific variation contributed more than inter-specific variation to the total variability of all the nutritional and stoichiometric characteristics, with intra-specific variation accounting for 68%, 70%, and 75% of the total variation in community-level N, P, and N:P, respectively. Negative covariations between the contribution of intra- and inter-specific variation occurred for community N and P concentrations. Further, N addition and mowing interacted to affect the impacts of intra- and inter-specific variation on community N concentration and N:P stoichiometry. CONCLUSIONS: Our results highlight different ways of trait selection for N addition and mowing treatments. Interactions between those two factors make it more difficult to accurately predict the responses of plant-mediated biogeochemical cycles under co-occurrence of environmental changes.

Mowing mitigates the negative impacts of N addition on plant species diversity.

Increasing availability of reactive nitrogen (N) threatens plant diversity in diverse ecosystems. While there is mounting evidence for the negative impacts of N deposition on one component of diversity, species richness, we know little about its effects on another one, species evenness. It is suspected that ecosystem management practice that removes nitrogen from the ecosystem, such as hay-harvesting by mowing in grasslands, would mitigate the negative impacts of N deposition on plant diversity. However, empirical evidence is scarce. Here, we reported the main and interactive effects of N deposition and mowing on plant diversity in a temperate meadow steppe with 4-year data from a field experiment within which multi-level N addition rates and multiple N compounds are considered. Across all the types of N compounds, species richness and evenness significantly decreased with the increases of N addition rate, which was mainly caused by the growth of a tall rhizomatous grass, Leymus chinensis. Such negative impacts of N addition were accumulating with time. Mowing significantly reduced the dominance of L. chinensis, and mitigated the negative impacts of N deposition on species evenness. We present robust evidence that N deposition threatened biodiversity by reducing both species richness and evenness, a process which could be alleviated by mowing. Our results highlight the changes of species evenness in driving the negative impacts of N deposition on plant diversity and the role of mowing in mediating such negative impacts of N deposition.