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In the era of the knowledge economy, with the increasing role of knowledge and entrepreneurship in cities, the impact of the urban knowledge environment on entrepreneurship has become an important research topic. Cities are the primary carriers of knowledge and entrepreneurship. However, few studies examine the impact of an urban knowledge environment on entrepreneurship. The impact of the urban knowledge environment on entrepreneurship in China remains unclear. Therefore, this study constructs an urban knowledge environment index from the two aspects of urban knowledge stock and knowledge infrastructure, measures the spatial distribution characteristics of the knowledge environment index of 275 cities at the prefecture level and above in China, and analyzes its impact using a spatial regression model. The results show that: (1) The urban knowledge environment index in the eastern coastal areas is relatively high, while that in the central and western areas is relatively low. Cities in major urban agglomerations, such as the Beijing Tianjin Hebei, Shandong Peninsula, Yangtze River Delta, Pearl River Delta, and Chengdu Chongqing urban agglomerations, have a high urban knowledge environment. The level of urban knowledge environment in provincial capitals and above is relatively high, whereas it is relatively low in general, prefecture-level cities. (2) Urban knowledge environments promote entrepreneurship. When other factors are controlled, entrepreneurship increases by 0.239% for every 1% increase in the urban knowledge environment index. (3) Spatial heterogeneity exists in the influence of the urban knowledge environment on entrepreneurship, and its marginal effect differs among cities in different regions and levels. Cities in the east had higher values than those in the central and western regions, and cities at or above the provincial capital level in the same region had higher values than ordinary prefecture-level cities. Among these, the increase in entrepreneurship caused by improving the knowledge environment index of cities at the provincial capital level and above is the largest, nearly three times higher than that of the eastern, central, western, and general cities. This study provides a theoretical basis and practical reference for the development of urban entrepreneurship in China in the new era by revealing the internal laws and impact mechanisms of the urban knowledge environment.

Purpose: New-onset proteinuria, as a pivotal sign of representative renal lesions in preeclampsia, is still the most common diagnostic tool for this condition and has been proven to be related to a significantly abnormal sFlt-1/VEGF ratio in circulation. At the same time, blood pressure control plays a vital role in the occurrence and evolution of proteinuria. Therefore, it is particularly helpful to investigate their interval, not only for performing urinalysis for protein more accurately but also for evaluating blood pressure as well as the aggravation of illness, as the related research is limited. Methods: This retrospective study included 515 preeclampsia patients and 358 normotensive pregnant women who labored in the Second Hospital of Tianjin Medical University from January 2016 to January 2020. First, we described the onset circumstance of high blood pressure and proteinuria as well as the interval among the case group and the subgroups. Then, we determined whether there were significant differences in the basic information, laboratory test results, and newborns between the case and normal groups. Finally, multifactor ANOVA was used to determine the factors influencing the interval. Results: 1. The two most common complications in preeclampsia were proteinuria (88.35%) and placental dysfunction (5.05%). Moreover, 72.04% of preeclampsia cases were diagnosed by abnormal blood pressure together with new-onset proteinuria. 2. The average interval between high blood pressure and proteinuria was 22 gestational days (from 0 to 106 days), and this interval was not significantly different between mild and severe PE (26 days vs. 21 days, P > 0.05) but significantly differed between early-onset and late-onset PE (9 days vs. 28 days, P < 0.05). 3. The number of prenatal visits, serum creatinine in the early trimester, gestational time and diastolic blood pressure value when increased blood pressure was initially detected may influence the interval between the onset of increased blood pressure and proteinuria. Conclusion: New-onset proteinuria was still the main parameter for identifying preeclampsia. The interval between increased blood pressure and proteinuria was probably related to the imbalance in the sFlt-1/VEGF ratio; therefore, we should pay attention to monitor proteinuria during the prenatal visits, especially for patients with a lower frequency of prenatal visits, higher serum creatinine in the early trimester, earlier onset and higher diastolic blood pressure at the initial onset of increased blood pressure. [ABSTRACT FROM AUTHOR]

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Invasive alien plants have rapidly established and spread in nature reserves via roads and now pose a threat to biodiversity. To understand the mechanism and distribution patterns of invasive alien herbs, we compared the altitude patterns of native and invasive alien herbs based on 105 plots in the Dayao Mountain National Nature Reserve. This study also compared the distribution patterns of new (introduced to China after 1900) and old (introduced to China before 1900) invasive alien herbs. In addition, we examined the effects of climatic factors and human activities on the distribution patterns of species richness. In our study, 151 native herbs species and 18 invasive alien herbs species were observed, of which 12 were new invasive alien herbs. Old invasive alien herbs occurred more frequently and occupied a wider range of altitudes than new invasive alien herbs. The richness of native herbs tended to decrease with increasing altitude, and the altitude patterns of the richness of all invasive herbs and new invasive alien herbs were hump-shaped. Based on an analysis using the linear mixed model, the results indicated that temperature was the main factor limiting the altitude patterns of native herbs, and that temperature and human activities were essential factors in the distribution and spread of all invasive alien herbs and new invasive alien herbs. The intensity of human interference is a crucial driver of the spread of new invasive alien herbs to higher altitudes. [ABSTRACT FROM AUTHOR]

As multiple invaders often co-occur, understanding the interactions between different invasive species is important. Previous studies have reported on invasional meltdown and neutral and interference relationships between invasive species. However, interspecific interactions may vary with environmental change owing to the different responses of interacting invaders. To better understand the interaction of notorious invasive alien plants under CO2 enrichment and N deposition, the growth characteristics of common ragweed (Ambrosia artemisiifolia) and redroot pigweed (Amaranthus retroflexus) were studied when they were planted in monoculture (4Rag and 4Pig) or mixture (1Rag:3Pig, 2Rag:2Pig, 3Rag:1Pig) under four environmental treatments: elevated CO2, increased N, elevated CO2 + increased N and a control. Increased N positively affected almost all the traits (basal stem diameter, height, shoot biomass, root biomass and total biomass) of common ragweed, except for branch number and root-shoot ratio. But increased N only promoted redroot pigweed's height and basal stem diameter. interspecific competition promoted basal stem diameter and number of branches but decreased root biomass of common ragweed, and the basal stem diameter was significantly higher in 1Rag:3Pig and 2Rag:2Pig compared to the other two treatments. interspecific competition inhibited almost all the characteristics of redroot pigweed. The interaction between elevated CO2 and increased N also increased the biomass characteristics (shoot biomass, root biomass and total biomass) of common ragweed. However, elevated CO2 inhibited the root biomass of redroot pigweed. The results indicated that common ragweed was a superior competitor under conditions of elevated CO2 and increased N. Moreover, environmental change might strengthen the super-invasive plant common ragweed's competitive ability. [ABSTRACT FROM AUTHOR]