Survey of Urban Geographical Environment Research Based on Urban Planning and Land-use

Every city was constructed on a region with special geomorphology. The construction and development of the city was based on it. The relationship between urban geographical environment and urban planning was intimate. This paper gave a brief introduction of the history and development of the urban geological research, urban geographical research, urban geomorphic disasters research and urban geographical environmental quality comprehensive assessment research based on the condition of urban planning and land-use. At last, the problem and the trend of urban geographical environment research were discussed

Abundance- and functional-based mechanisms of plant diversity loss with fertilization in the presence and absence of herbivores

Nutrient supply and herbivores can regulate plant species composition, biodiversity and functioning of terrestrial ecosystems. Nutrient enrichment frequently increases plant productivity and decreases diversity while herbivores tend to maintain plant diversity in productive systems. However, the mechanisms by which nutrient enrichment and herbivores regulate plant diversity remain unclear. Abundance-based mechanisms propose that fertilization leads to the extinction of rare species due to random loss of individuals of all species. In contrast, functional-based mechanisms propose that species exclusion is based on functional traits which are disadvantageous under fertilized conditions. We tested mechanistic links between fertilization and diversity loss in the presence or absence of consumers using data from a 4-year fertilization and fencing experiment in an alpine meadow. We found that both abundance- and functional-based mechanisms simultaneously affected species loss in the absence of herbivores while only abundance-based mechanisms affected species loss in the presence of herbivores. Our results indicate that an abundance-based mechanism may consistently play a role in the loss of plant diversity with fertilization, and that diversity decline is driven primarily by the loss of rare species regardless of a plant's functional traits and whether or not herbivores are present. Increasing efforts to conserve rare species in the context of ecosystem eutrophication is a central challenge for grazed grassland ecosystems

Intra-annual growing season climate variability drives the community intra-annual stability of a temperate grassland by altering intra-annual species asynchrony and richness in Inner Mongolia, China

Understanding the factors that regulate the functioning of our ecosystems in response to environmental changes can help to maintain the stable provisioning of ecosystem services to mankind. This is especially relevant given the increased variability of environmental conditions due to human activities. In particular, maintaining a stable production and plant biomass during the growing season (intra-annual stability) despite pervasive and directional changes in temperature and precipitation through time can help to secure food supply to wild animals, livestock, and humans. Here, we conducted a 29-year field observational study in a temperate grassland to explore how the intra-annual stability of primary productivity is influenced by biotic and abiotic variables through time. We found that intra-annual precipitation variability in the growing season indirectly influenced the community intra-annual biomass stability by its negative effect on intra-annual species asynchrony. While the intra-annual temperature variability in the growing season indirectly altered community intra-annual biomass stability through affecting the intra-annual species richness. At the same time, although the intra-annual biomass stability of the dominant species and the dominant functional group were insensitive to climate variability, they also promoted the stable community biomass to a certain extent. Our results indicate that ongoing intra-annual climate variability affects community intra-annual biomass stability in the temperate grassland, which has important theoretical significance for us to take active measures to deal with climate change

Species richness and asynchrony maintain the stability of primary productivity against seasonal climatic variability

The stability of grassland communities informs us about the ability of grasslands to provide reliable services despite environmental fluctuations. There is large evidence that higher plant diversity and asynchrony among species stabilizes grassland primary productivity against interannual climate variability. Whether biodiversity and asynchrony among species and functional groups stabilize grassland productivity against seasonal climate variability remains unknown. Here, using 29-year monitoring of a temperate grassland, we found lower community temporal stability with higher seasonal climate variability (temperature and precipitation). This was due to a combination of processes including related species richness, species asynchrony, functional group asynchrony and dominant species stability. Among those processes, functional group asynchrony had the strongest contribution to community compensatory dynamics and community stability. Based on a long-term study spanning 29 years, our results indicate that biodiversity and compensatory dynamics a key for the stable provision of grassland function against increasing seasonal climate variability

A geometric dilution of precision based 3D indoor positioning scheme

A geometric dilution of precision(GDOP) based 3D indoor positioning scheme was proposed for the layout of anchor nodes.Through the proposed scheme,the biconical configuration could be obtained.The performance of the scheme was evaluated by utilizing two different ranging error models.Simulation results indicated that the scheme can be applied to various scenes with different sizes.Furthermore,the proposed scheme had considerable accuracy improvement in the same positioning environment compared with existing layout scheme

A familiar peer improves students’ behavior patterns, attention, and performance when learning from video lectures

Abstract Synchronous online learning via technology has become a major trend in institutions of higher education, allowing students to learn from video lectures alongside their peers online. However, relatively little research has focused on the influence of these peers on students’ learning during video lectures and even less on the effect of peer familiarity. The present study aimed to test the various effects of peer presence and peer familiarity on learning from video lectures. There were three experimental conditions: individual-learning, paired-learning with an unfamiliar peer, and paired-learning with a familiar peer. ANCOVA results found that students paired with a familiar peer reported higher motivation in learning and more self-monitoring behaviors than those paired with an unfamiliar peer or who learned alone. Furthermore, students paired with both unfamiliar or familiar peers demonstrated better learning transfer than those who learned alone. Together, these results confirm the benefits of and support learning alongside a familiar peer during video lectures