Dynamics of soil organic carbon and microbial biomass carbon in relation to water erosion and tillage erosion.

Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the (137)Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of (137)Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. (137)Cs data revealed that soil loss occurred at upper slope positions of the two landscapes and soil accumulation at the lower slope positions. Soil erosion rates as well as distribution patterns of the <0.002-mm clay shows that water erosion is the major process of soil redistribution in the gentle slope landscape, while tillage erosion acts as the dominant process of soil redistribution in the steep slope landscape. In gentle slope landscapes, both SOC and MBC contents increased downslope and these distribution patterns were closely linked to soil redistribution rates. In steep slope landscapes, only SOC contents increased downslope, dependent on soil redistribution. It is noticeable that MBC/SOC ratios were significantly lower in gentle slope landscapes than in steep slope landscapes, implying that water erosion has a negative effect on the microbial biomass compared with tillage erosion. It is suggested that MBC dynamics are closely associated with soil redistribution by water erosion but independent of that by tillage erosion, while SOC dynamics are influenced by soil redistribution by both water erosion and tillage erosion

Distribution of the <0.002-mm particle-size fraction on eroded slopes.

<p>Distribution of the <0.002-mm particle-size fraction on eroded slopes.</p

Descriptive statistics of ¹³⁷Cs inventories, SOC and MBC contents in different positions for gentle and steep slope landscapes.

♀<p>single value in the position.</p

Distribution of ¹³⁷Cs inventories over eroded slopes.

<p>(a) gentle slope landscape; (b) steep slope landscape.</p

Relationship between MBC and SOC in gentle and steep slope landscapes.

<p>(a) mass basis; (b) area basis.</p

SOC contents vs. ¹³⁷Cs inventories in gentle and steep slope landscapes.

<p>SOC contents vs. ¹³⁷Cs inventories in gentle and steep slope landscapes.</p

Using Geotagged Social Media Data to Explore Sentiment Changes in Tourist Flow: A Spatiotemporal Analytical Framework

Understanding sentiment changes in tourist flow is critical in designing exciting experiences for tourists and promoting sustainable tourism development. This paper proposes a novel analytical framework to investigate the tourist sentiment changes between different attractions based on geotagged social media data. Our framework mainly focuses on visualizing the detailed sentiment changes of tourists and exploring the valuable spatiotemporal pattern of the sentiment changes in tourist flow. The tourists were first identified from social media users. Then, we accurately evaluated the tourist sentiment by constructing a Chinese sentiment dictionary, grammatical rule, and sentiment score. Based on the location information of social media data, we built and visualized the tourist flow network. Last, to further reveal the impact of attractions on the sentiment of tourist flow, the positive and negative sentiment profiles were generated by mining social media texts. We took Beijing, a famous tourist destination in China, as a case study. Our results revealed the following: (1) the temporal trend of tourist sentiment has seasonal characteristics and is significantly influenced by government control policies against COVID-19; (2) due to the impact of the attraction’s historical background, some tourist flows with highly decreased sentiment strength are linked to attractions; (3) on the long journey to the attraction, the sentiment strength of tourists decreases; and (4) bad traffic conditions can significantly decrease tourist sentiment. This study highlights the methodological implications of visualizing sentiment changes during collective tourist movement and provides comprehensive insight into the spatiotemporal pattern of tourist sentiment

Multidrug- Resistant Atypical Variants of Shigella flexneri

We identified 3 atypical Shigella flexneri varieties in China, including 92 strains with multidrug resistance, distinct pulse types, and a novel sequence type. Atypical varieties were prevalent mainly in developed regions, and 1 variant has become the dominant Shigella spp. serotype in China. Improved surveillance will help guide the prevention and control of shigellosis. Each year worldwide, ≈1.5 million children &lt;5 years of age die from diarrheal diseases (1), which is of particular concern in developing countries. Shigella spp. are leading bacterial causes of diarrhea, responsible for&gt;80 million cases of bloody diarrhea and 700,000 deaths each year (2), and S. flexneri serotype 2a has been recognized as the most prevalent serotype in China for many years (3). To better understand the etiology of bacterial diarrhea in China and to determine if S. flexneri serotype 2a is still the most prevalent serotype in China, we conducted a study during May 2008–December 2010. The Study A total of 10,021 fecal samples were obtained from patients with diarrhea or dysentery at hospitals in 8 provinces within the eastern, southern, western, northern, an