Effects of grazing disturbance of spatial distribution pattern and interspecies relationship of two desert shrubs

Grazing significantly affects the distribution,growth,and productivity of shrubs.In this study,we evalu-ated the effects of grazing disturbance on the spatial distri-bution patterns and interspecific relationships of two desert shrubs,Ammopiptanthus mongolicus and Sarcozygium xan-thoxylon.Three types of grazing conditions were considered,including enclosed area(EA),seasonal rotational grazing area(SRGA),and grazing area(GA)(100 m×100 m),in the West Ordos Nature Reserve of Inner Mongolia,China.The results showed that A.mongolicus and S.xanthoxylon populations were uniformly distributed at a small scale,and the distribution in EA and SRGA became gradually ran-dom.In GA,A.mongolicus population showed aggregated distribution but S.xanthoxylon population showed random distribution at a small scale. Moreover, both A. mongolicus and S. xanthoxylon populations at the 5-7 m scale showed random distribution. At the small and intermediate scales, the two species showed positive interspecific relationships of GA. However, no interspecific relationship was noted between the two species in EA and SRGA. A significant positive relationship (P < 0.01) was noted between the two species at 2-9 m and a negative relationship (P < 0.01) at 13-17 m scales in GA. Positive relationship (P < 0.01) was noted between the two species at 6-13 m scales and a sig-nificant negative relationship (P < 0.01) at 14-24 m scales in SRGA. The two species of desert shrubs showed posi-tive interspecific relationships at the small scale, and they showed negative relationships as the interspecific compe-tition intensified in the presence of grazing disturbance. When the grazing intensity exceeds a certain threshold, the interspecific relationships become weak. Therefore, moder-ate grazing would facilitate interspecific competition and species succession, whereas excessive grazing would disrupt natural competition causing desertification ultimately.

Prediction of Th17/Treg cell balance on length of stay in intensive care units of patients with sepsis

Background Prolonged length of stay(LOS)of sepsis can drain a hospital's material and human resources.This study investigated the correlations between T helper type 17(Th17)and regulatory T(Treg)balance with LOS in sepsis.Methods A prospective clinical observational study was designed in Changhai Hospital affiliated to Naval Medical University in Shanghai,China,from January to October 2020.The patients diagnosed with sepsis and who met the inclusion and exclusion criteria were recruited and whether the levels of cytokines,procalcitonin,subtypes,and biomarkers of T cells in the peripheral blood were detected.We analyzed the correlation between these and LOS.Results Sixty septic patients were classified into two groups according to whether their intensive care unit(ICU)stay exceeded 14 days.The patients with LOS≥14 days were older([72.6±7.5]years vs.[63.3±10.4]years,P=0.015)and had higher Sequential Organ Failure Assessment(SOFA)(median[interquartile range]:6.5[5.0–11.0]vs.4.0[3.0–6.0],P=0.001)and higher Acute Physiology and Chronic Health Evaluation(APACHE)II scores(16.0[13.0–21.0]vs.8.5[7.0–14.0],P=0.001).There was no difference in other demographic characteristics and cytokines,interleukin-6,tumor necrosis factor-α,and interleukin-10 between the two groups.The Th17/Treg ratio of sepsis with LOS<14 days was considerably lower(0.48[0.38–0.56]vs.0.69[0.51–0.98],P=0.001).For patients with LOS≥14 days,the area under the receiver operating characteristic curve for the Th17/Treg ratio was 0.766.It improved to 0.840 and 0.850 when combined with the SOFA and APACHE II scores,respectively.Conclusions The Th17/Treg ratio was proportional to septic severity and can be used as a potential predictor of ICU stay in sepsis,presenting a new option for ICU practitioners to better care for patients with sepsis.