Travel Behaviours of Sharing Bicycles in the Central Urban Area Based on Geographically Weighted Regression: The Case of Guangzhou, China

Mobile information and communication technologies(MICTs) have fully penetrated everyday life in smart societies;this has greatly compressed time, space, and distance, and consequently, reshaped residents’ travel behaviour patterns. As a new mode of shared mobility, the sharing bicycle offers a variety of options for the daily travel of urban residents. Extant studies have mainly examined the travel characteristics and influencing factors of public bicycles with piles, while the travel patterns for sharing bicycles and their driving mechanisms have been largely ignored. Using one week’s travel data for Mobike, this study investigated the spatial and temporal distribution patterns of sharing bicycle travel behaviours in the central urban area of Guangzhou, China;furthermore, it identified the influences of built environment density factors on sharing bicycle travel behaviours based on the geographically weighted regression method. Obvious morning and evening peaks were observed in the sharing bicycle travel patterns for both weekdays and weekends. The old urban area, which had a high degree of mixed function, dense road networks, and cycling-friendly built environments, was the main travel area that attracted sharing bicycles on both weekdays and weekends. Furthermore, factors including the point of interest(POI) for the density of public transport stations, the functional mixing degree, and the density of residential POIs significantly affected residents’ travel behaviours. These findings could enrich discourse regarding shared mobility with a Chinese case characterised by rapidly developing MICTs and also provide references to local authorities for improving slow traffic environments.

Building Height Trends and Their Influencing Factors under China’s Rapid Urbanization:A Case Study of Guangzhou,1960–2017

Understanding the spatiotemporal patterns of three-dimensional urban forms,especially building height,can have important implications for improving urban air quality and mitigating the urban heat island effect by optimizing urban planning and management policies.This study investigated building height evolution and its influencing factors over approximately half a century(1960–2017)in Guangzhou,China.The results indicated that the logarithmic declines in height,quantity,and area of urban buildings followed Zapf’s law,which restricts the three-dimensional shape of the urban form.The urban building height decreased from the center to the periphery of the city and decreased with decreasing altitude and increasing distance from main roads.These characteristics constituted the three main spatial differentiation rules of building height in the central district of Guangzhou,and all exhibited a logarithmic decrease,which gradually strengthened over time.The development of a double-layered height structure of low-rise and high-rise buildings between 1990 and 2017 was a notable manifestation of the increase in vertical urban height over time.The three factors of city center,altitude,and accessibility,which represent centrality,low relief,proximity to water,and proximity to road networks,highlighted the roles of traffic accessibility and commercial attraction in building height evolution.The importance of location macroscopically depends on the combined effect of the geographical pattern,urban planning,and market forces of cities located on a plain near hill or by a river.The principle of profit orientation restricted spatiotemporal building height patterns.

Excess Commuting in Transitional Urban China:A Case Study of Guangzhou

During the reform era, Chinese cities witnessed dramatic institutional transformation and spatial restructuring in general and profound change of commuting patterns in particular. Using household surveys collected in Guangzhou, China, in 2001, 2005 and 2010, excess commuting measurements are estimated. Excess commuting shows an overall trend of increasing during 1990–1999, and then declining during 2000–2010. We argue that deepening marketization of the jobs and housing sectors has induced spatial separation of jobs and housing. In other words, institutional transition and urban spatial restructuring are underpinning the changes of commuting patterns in Chinese cities. Excess commuting has strong relationship with individual socio-demographic status, which is by and large due to the increasing flexibilities of jobs and housing location choices enjoyed by urban residents. The findings call for considerations on balancing jobs-housing in making public policies relevant to urban development in general, and land use and transportation in particular.

Dengue Fever Epidemiological Status and Relationship with Meteorological Variables in Guangzhou, Southern China, 2007-2012

Ecological methodology plus negative binomial regression were used to identify dengue fever （DF） epidemiological status and its relationship with meteorological variables. From 2007 to 2012, annual incidence rate of DF in Guangzhou was 0.33, 0.11, 0.15, 0.64, 0.45, and 1.34 （per 100 000） respectively, showing an increasing trend. Each 1℃ rise of temperature corresponded to an increase of 10.23% （95% CI 7.68% to 12.83%） in the monthly number of DF cases, whereas l hPa rise of atmospheric pressure corresponded to a decrease in the number of cases by 5.14% （95% CI： 7.10%-3.14%）. Likewise, each one meter per second rise in wind velocity led to an increase by 43.80% or 107.53%, and one percent rise of relative humidity led to an increase by 2.04% or 2.19%.

Spatial-temporal Characteristics and Factors Influencing Commuting Activities of Middle-class Residents in Guangzhou City, China

The middle class in metropolitan Chinese cities has become an important social group. With the rapid development of urbanization and constant advancement of suburbanization, the middle class has increasingly come to influence city traffic. Research into middle-class commuting activities thus has practical significance for improving traffic congestion and reducing the commuting burden in metropolitan cities. Based on a dataset formed by 816 completed surveys, this paper analyzes the commuting mode, time and distance of middle-class residents in Guangzhou City using the descriptive statistical method. The results indicate that private cars are the main commuting mode, followed by public transport. Meanwhile, middle-class residents mainly undertake medium-short time and medium-short distance commuting. The study subsequently uses multilevel logistic regression and multiple linear regression models to analyze the factors that influence commuting mode choice, time and distance. The gender, age, number of family cars, housing source and jobs-housing balance are the most important factors influencing commuting mode choice; housing, population density, jobs-housing balance and commuting mode significantly affect commuting time; and transport accessibility, jobs-housing balance and commuting mode are the notable factors affecting commuting distance. Finally, this paper analyzes what is affecting the commuting activities of middle-class residents and determines the differences in commuting activity characteristics and influence factors between middle-class and ordinary residents. Policy suggestions to improve urban planning and urban management are also proposed.

Distribution of Microbiota in Fine Particulate Matter Particles in Guangzhou, China

Objective High PM2.5 concentration is the main feature of increasing haze in developing states,but information on its microbial composition remains very limited.This study aimed to determine the composition of microbiota in PM2.5 in Guangzhou,a city located in the tropics in China.Methods In Guangzhou,from March 5th to 10th,2016,PM2.5 was collected in middle volume air samplers for 23 h daily.The 16 S rDNA V4 region of the PM2.5 sample extracted DNA was investigated using high-throughput sequence.Results Among the Guangzhou samples,Proteobacteria,Bacteroidetes,Firmicutes,Cyanobacteria,and Actinobacteria were the dominant microbiota accounting for more than 90%of the total microbiota,and Stenotrophomonas was the dominant gram-negative bacteria,accounting for 21.30%–23.57%.We examined the difference in bacterial distribution of PM2.5 between Beijing and Guangzhou at the genus level;Stenotrophomonas was found in both studies,but Escherichia was only detected in Guangzhou.Conclusion In conclusion,the diversity and specificity of microbial components in Guangzhou PM2.5 were studied,which may provide a basis for future pathogenicity research in the tropics.

Contamination of Prohibited Substances in Various Food Products in Guangzhou, China

The use of antibiotics to maintain animal health has widely been practiced,for both therapeutic and prophylactic purposes.Along with the identification of serious adverse effects of some antibiotics on human and domestic animals[1],chloramphenicol.

The First Congress of New Development on Molecular Imaging Dec 22 to 24,2011,Guangzhou,China

"The First Congress of New Development on Molecular Imaging" will be held in Guangdong Hotel in Guangzhou, Guangdong province, Dec 22 to 24, 2011. This conference is hosted by Ultrasound Medical Branch of Guangdong Medical Association, Ultrasound Medical Branch of Guangzhou Medical Association, is undertaken by

First Asia-Pacific Symposium on Visual Sciences November 2-5,1994 Guangzhou,PR China

With the largest population in the world,the Asia-Pacific area is in a great need for the fundamentalresearch of visual sciences,the protection of vision and the prevention and treatment of visual diseases.The Symposium will open a new era of the academic exchanges in the field of visual sciences in thisarea.It also will enhance the academic exchanges of visual sciences worldwide.

Fabrics China Trends Released in Guangzhou

During April 8th-14th,China Textiles Development center,along with China Textile Information Center,released their newly

Roles of urban vegetation on balance of carbon and oxygen in Guangzhou, China

The plant biomass and net primary production(NPP) of urban vegetation in Guangzhou were estimated by dimension analysis, tree truck volume, and harvest methods as well as relationship between biomass and NPP and so on. The biomass and NPP were respectively 2875150t and 1058122 t/a. They were respectively 392495t and 64948 t/a in the built-up area and 2482655t and 993147 t/a in the unbuilt-up area. It would make plant biomass, especially NPP decline obviously, if the unbuilt-up area were changed to the built-up area. The carbon content of plant was 1328649 for the total and 13.78 t/hm 2 for the mean, and amounts of carbon fixed and oxygen made by urban vegetation were respectively 4.80 t/(hm 2·a) and 12.79 t/(hm 2·a) for the mean and 462624 t/a and 1232430 t/a for the total, which were equal to 1.45 times and 1.04 times of those by human breathing. However, they were only equal to 7.61% and 4.97% of amount of carbon released and oxygen consumption in urban Guangzhou. The biomass and NPP of urban vegetation in Guangzhou only corresponded to 7.8% and 47.3% of those of southern subtropical evergreen broad-leaf forest in Dinghu Mountain. Therefore, the roles of Guangzhou urban vegetation in balance of carbon and oxygen would be increased greatly if it could be conserved and improved in some way.

Evaluation of ambient air quality in Guangzhou, China

On the basis of the reported air quality index （API） and air pollutant monitoring data provided by the Guangzhou Environment Monitoring Stations over the last twenty-five years, the characteristics of air quality, prominent pollutants, and variation of the average annual concentrations of SOE, NOE, total suspended particulate （TSP）, fine particulates （PM10）, CO and dustfall in Guangzhou City were analyzed. Results showed that TSP was the prominent pollutant in the ambient air environment of Guangzhou City. Of the prominent pollutants, TSP accounted for nearly 62%, SOE 12.3%, and NOx 6.4%, respectively. The average API of Guangzhou over 6 years was higher than that of Beijing, Tianjin, Nanjing, Hangzhou, Suzhou and Shanghai, and lower than that of Shenzhen, Zhuhai and Shantou. Concentrations of air pollutants have shown a downward trend in recent years, but they are generally worse than ambient air quality standards for USA, Hong Kong and EU. SOE and NOx pollution were still serious, impling that waste gas pollution from all kinds of vehicles had become a significant problem for environmental protection in Guangzhou. The possible causes of worsening air quality were also discussed in this paper.

Distribution and deposition of polycyclic aromatic hydrocarbons in precipitation in Guangzhou, South China

Polycyclic aromatic hydrocarbons （PAHs） were measured in precipitation from March to August 2005 in Guangzhou, South China. Fourteen PAHs were studied, and their total concentrations varied from 616.6 to 3486.7 ng/L in dissolved phase and from 403.8 to 3125.5 ng/L in particulate phase. The estimated deposition loading of PAHs was 3568 ug/m^2 during the monitoring period. The deposition of PAHs was a potential source for Pearl River comparing with the contents of surface water. In addition, the high concentration in precipitation here implied that PAHs pollution was a potential environmental problem in Guangzhou. Most precipitation concentrations of PAHs in March （the last month in winter in Guangzhou） were higher than in the other months （in rainy season）. PAHs inclined to be adsorbed to particulate phase with the increase of molecular weight in rainwater. Combustion of fossil fuel and biomass might be the major source of PAHs, while the direct leakage or volatilization from petroleum products might be insignificant.

Impact of Heat Wave in 2005 on Mortality in Guangzhou, China

Objective To assess the impact of the heat wave in 2005 on mortality among the residents in Guangzhou and to identify susceptible subpopulations in Guangzhou, China. Methods The data of daily number of deaths and meteorological measures from 2003 to 2006 in Guangzhou were used in this study. Heat wave was defined as 〉7 consecutive days with daily maximum temperature above 35.0 ~C and daily mean temperature above the 97th percentile during the study period. The excess deaths and rate ratio （RR） of mortality in the case period compared with the reference period in the same summer were calculated. Results During the study period, only one heat wave in 2005 was identified and the total number of excess deaths was 145 with an average of 12 deaths per day. The effect of the heat wave on non-accidental mortality （RR=l.23, 95% CI： 1.11-1.37） was found with statistically significant difference. Also, greater effects were observed for cardiovascular mortality （RR=l.34, 95% Cl： 1.13-1.59） and respiratory mortality （RR=I.31, 95% CI： 1.02-1.69）. Females, the elderly and people with lower socioeconomic status were at significantly higher risk of heat wave-associated mortality. Conclusion The 2005 heat wave had a substantial impact on mortality among the residents in Guangzhou, particularly among some susceptible subpopulations. The findings from the present study may provide scientific evidences to develop relevant public health policies and prevention measures aimed at reduction of preventable mortality from heat waves.

Landscape ecological analysis of urban vegetation in Guangzhou,China

The compositions, patches and landscape heteorogentity of Guangzhou urban vegetation are studied by using the principles of landscape ecology in this paper. The results showed that the area of urban vegetation was 26901 4hm 2, and the distribution of vegetation types and regional vegetation coverage were uneven. The patch areas of vegetation were large in scenery vegetation and shelter vegetation, and small in street corner vegetation and small garden vegetation. Most of patches fell in range between 100 and 10000 m 2. Only 1.13% of patches were larger than 1000000 m 2. Structure features of vegetation landscape in old urban areas were small patch, high scattering degree, high diversity, random distribution of vegetation patches and high heterogeneity. In new urban areas, the features were big patches, fine planning, medium landscape heterogeneity. Some suggestions are made according to landscape character of urban vegetation in Guangzhou.

Trans Fatty Acid Levels in Foods and Intakes among Population Aged 3 Years and above in Beijing and Guangzhou Cities,China

Objective To understand the dietary intake levels of trans fatty acids （TFA） in a Chinese population and establish a basis for health risk assessment of trans fatty acids. Methods The TFA contents data of 2613 food items and food consumption data of 10,533 people aged 3 years and above in two large cities in China were matched and a simple assessment method was used to estimate the distribution of dietary TFA intake. Results The mean content of TFA was highest in margarine （1.68±0.83 g/100g）, followed by chocolate and candy （0.89±2.68 g/100g）, edible vegetable oils （0.86±0.82 g/100g）, milk （0.83±1.56 g/100g）, and bakery foods （0.41±0.91 g/100g）. TFA intake accounted for 0.34%, 0.30%, 0.32%, and 0.29% of the total energy intake in the 3-6, 7-12, 13-17, and 〉18 year age groups, respectively. Of the populations studied, 0.42% demonstrated TFA intakes （as percentage of energy intake） greater than 1%. The main sources of dietary TFA intake were edible vegetable oils, milk, mutton, and beef, and baked foods, which accounted for 49.8%, 16.56%, 12.21%, and 8.87%, respectively. Conclusion The current intake of TFA among concern regarding the threshold of TFA intake people in two cities did not appear to be of major health as the percentage of total energy recommended by the World Health Organization. Because most TFA were derived from industrially processed foods, the government should reinforce nutrition labeling and regulate food producers to further reduce TFA in food and to provide scientific instruction for consumers to make sound choices.

Private Car Travel Characteristics and Influencing Factors in Chinese Cities——A Case Study of Guangzhou in Guangdong,China

Taking Guangzhou as a case,this paper adopted a questionnaire survey to gather first-hand data and analyzed the characteristics and influencing factors of private car travel in Chinese cities.As the research indicated,trip purposes of private car travel are mainly commute and business affairs with a more flexible trip in the urban core area.And trip intensities are concentrated in a certain extent,with trip frequency being lower in the urban core area than the peripheral area.In addition,the trip time has two significant peaks occurring in the morning and afternoon,and one trough in the midday.And trip spatial distribution is mainly within commute with both residence and employment in urban area and inward commute with residence in suburban area while employment in urban area.Both kinds of commutes direct to the urban area.The study also shows that the characteristics of private car travel are principally influenced by two aspects:travelers' attributes and urban characteristics.The main travelers' social and economic attributes influenced it include the gender,education attainment,age,driving experience and per capita monthly household income.The urban characteristics influenced it mainly cover the land use pattern,public traffic facilities and spatial attributes of residential environment.

Identification and Typing of Respiratory Adenoviruses in Guangzhou, Southern China Using a Rapid and Simple Method

Human adenoviruses (HAdVs), especially HAdV-B3, -E4 and -B7, are associated with Acute Respiratory Disease in Chinese children, and occasionally in adults. In order to establish and document the profiles of the respiratory adenovirus pathogen among children in Guangzhou, Southern China, a rapid, simple and practical method for identification and typing of respiratory adenoviruses was developed and evaluated. One pair of universal PCR primers was designed according to the conserved region of the hexon gene, which can detect not only HAdV-B3, -E4 and -B7, but also HAdV-B14, -F40 and -F41, with a specific 300bp PCR product. Three pairs of type-specific PCR primers were also designed according to the hypervariable regions of the hexon gene to type HAdV-B3, -E4 and -B7 by three independent PCR reactions, making it easy to optimize the PCR conditions. By using this method, one hundred throat swab specimens collected during Oct 2010 to Dec 2011 and suspected of being positive for adenoviral infection were identified and typed for adenoviruses. Of these samples, fifty-five were adenovirus-positive. The most common HAdV type was HAdV-B3, identified in 92.7% of samples, which is not only consistent with the data reported in 2004-2006, but also consistent with the recent report in Hangzhou, eastern China, indicating that HAdV-B3 has been circulating in Guangzhou, and maybe in eastern China, for many years. The method for the respiratory adenovirus identification and typing we developed is rapid, simple and practical, which has a potential in the real-time surveillance of circulating adenovirus strains and also to provide etiological evidence for the adenovirus-relative disease control and prevention in China.