The effect of portal hypertension on transforming growth factor-alpha and epidermal growth factor receptor in the gastric mucosa of rats

BACKGROUND: The physical activity levels of US children are declining. Opportunities for physical activity within city schools are constrained by time and space limits. This study determined whether a supplemental program of physical activity would significantly alter the fitness levels of low-income, minority, urban elementary schoolchildren. METHODS: Ninety-nine students from two Cleveland Public Schools served as subjects. One school received a 15-week intervention program where teams of two medical students met with urban elementary schoolchildren three times a week for physical activity sessions. The other school served as a control and received no supplemental activity other than a regularly scheduled physical education class held once a week. We obtained field measurements of skinfold thickness, heart rate response to submaximal exercise, and sit and reach flexibility. RESULTS: The supplemental activity group showed significant improvements in flexibility, body composition, and heart rate response to submaximal exercise. CONCLUSIONS: This investigation indicates that a program of fitness activities conducted within the classroom can significantly improve levels of fitness in urban elementary schoolchildren.     

中国县域可达性研究——特征及其对人口分布的影响

This paper calculated spatial accessibility of all counties (city, urban district) in China with cost weighted distance method. Region divisions of county accessibility were conducted, and relation of traffic accessibility and population aggregation was discussed in this paper. The results indicated that county accessibility in China had mainly low values and a distribution structure of circle layer and reverse-to-natural gradient. There was an obvious correlation between county accessibility and population density in China. With these analyses,inner mechanisms of population migration in different traffic conditions and region types were revealed, and can provide useful proposals to regional planning, traffic planning and smart distribution of people in China.     

区域尺度城市增长时空动态模型及其在京津唐都市圈应用

Dynamic urban expansion simulation at regional scale is one of the important re-search methodologies in Land Use/Cover Change (LUCC) and global environmental change influenced by urbanization. However, previous studies indicate that the single urban expan-sion simulation for future scenarios at local scale cannot meet the requirements for charac-terizing and interpreting the interactive mechanisms of regional urbanization and global en-vironmental change. This study constructed a regional Dynamic Urban Expansion Model (Reg-DUEM) suitable for different scenarios by integrating the Artificial Neural Network (ANN)and Cellular Automaton (CA) model. Firstly we analyzed the temporal and spatial character-istics of urban expansion and acquired a prior knowledge rules using land use/cover change datasets of Beijing-Tianjin-Tangshan metropolitan area. The future urban expansion under different scenarios is then simulated based on a baseline model, economic models, policy models and the structural adjustment model. The results indicate that Reg-DUEM has good reliability for a non-linear expansion simulation at regional scale influenced by macro-policies.The simulating results show that future urban expansion patterns from different scenarios of the metropolitan area have the tremendous spatio-temporal differences. Future urban ex-pansion will shift quickly from Beijing metropolis to the periphery of Tianjin and Tangshan city along coastal belt.     

Growth screening and urban deprivation

OBJECTIVES: To assess the effect of urban deprivation on childhood growth in a modern British society by analysing data from a regional growth survey, the Tayside growth study. SETTING: The Tayside Region in Scotland, which has three districts with distinct socioeconomic status: Dundee (D, urban city), Angus (A, rural), and Perth (P, rural and county town). SUBJECTS AND METHODS: Height and weight of 23,046 children (> 90% of the regional childhood population) were measured as part of a child health surveillance programme, by community health care workers at 3, 5, 7, 9, 11, and 14 years. Height standard deviation score (calculated against Tanner) and body mass index (BMI-weight (kg)/height (m)2) were calculated for each child by a central computer program; mean height standard deviation score and BMI standard deviation score were calculated for each measuring centre (school, health clinic). A deprivation score for each centre was calculated from the prevalence of single parent families; families with more than three children; unemployment rate; the number of social class V individuals; the percentage of council houses. RESULTS: Mean height standard deviation score for Tayside was 0.11. An intraregional difference was demonstrated: mean height standard deviation score (SD) D = 0.04 (1.0); A = 0.14 (1.1); P = 0.21 (1.1); P < 0.002. There was a positive association between short stature and increasing social deprivation seen throughout Tayside (P < 0.05), with a strong association in Dundee primary school children (r = 0.6; P < 0.001). Analysis by district showed that the association was significant only above the age of 8 (P < 0.004). There was no relation between BMI and social deprivation. CONCLUSIONS: In an industrialised developed society, urban deprivation appears to influence height mostly in late childhood, and this association should be taken into consideration in the clinical management of short stature. Height seems to be a better physical indicator of urban deprivation, and hence an index of childhood health, than BMI.     

胶西北焦家金矿田控矿构造分析

焦家金矿田是胶西北矿集区最大的金矿田。在简要概述区域构造背景的基础上,结合玲珑花岗杂岩体重力异常、杂岩体重力延拓特征与矿田构造分析,重点探讨了郭家店幔枝构造的形态特征及其成矿控矿作用,认为地幔热柱多级演化沟通了深部成矿物质来源,郭家店幔枝构造外围拆离带发育的一系列韧-脆性剪切带控制着招远-平度矿集区的矿床分布。在研究焦家金矿控矿构造、矿体展布、垂向延伸和蚀变特征等基础上,总结了焦家金矿田的成矿作用,推测该区进一步找矿方向。     

基于CiteSpace的资源型产业研究知识图谱分析

资源型产业发展为推进国家经济增长和工业化进程提供了重要保障。为深入了解资源型产业的研究情况，以CNKI数据库为数据源，搜集2000—2020年关于资源型产业的核心及以上期刊论文，利用CiteSpace软件从发文作者与研究机构分布、关键词共现网络和时区图谱等方面，绘制知识图谱，进行可视化分析。研究发现：资源型产业领域的研究成果愈加丰富，但研究群体间联系合作较少，且现有的合作研究主要集中在所处地域资源富集和具有学科优势的研究机构及学者；资源型产业领域的研究热点可概括为产业发展、资源型城市、产业集群、产业结构、产业链和产业集聚等方面；针对资源型产业领域未来可从资源型产业相关理论研究、创新发展模式和可持续发展等方面深入展开。     

基于GIS的城市土壤氡浓度分布规律和健康风险评价

研究城市土壤氡浓度分布特征和健康风险评价,填补城市地质调查放射性领域空白,为城市开发建设提供基础数据。运用GIS分析技术,将研究区划分为特定区域型、线型和区域型三种调查尺度,应用地累积指数法、内梅罗指数法和潜在生态危害指数法进行了土壤氡风险评价。结果表明：1)用地累积指数、内梅罗指数、潜在生态危害指数测算健康风险,全区污染等级和污染指数分别为清洁(-0.287)、轻度污染(2.585)和生态危害高(103.42),各尺度调查对象土壤氡污染程度排序为：全区地质体>全区>秋长构造>沙田构造>秋长社区空地;2)地累积指数、内梅罗指数和潜在生态危害指数测算不同调查尺度的土壤氡健康风险水平基本一致,可作为土壤氡健康风险评价较有效方法。     

Evolutionary artificial neural networks

Evolutionary artificial neural networks (EANNs) can be considered as a combination of artificial neural networks (ANNs) and evolutionary search procedures such as genetic algorithms (GAs). This paper distinguishes among three levels of evolution in EANNs, i.e. the evolution of connection weights, architectures and learning rules. It first reviews each kind of evolution in detail and then analyses major issues related to each kind of evolution. It is shown in the paper that although there is a lot of work on the evolution of connection weights and architectures, research on the evolution of learning rules is still in its early stages. Interactions among different levels of evolution are far from being understood. It is argued in the paper that the evolution of learning rules and its interactions with other levels of evolution play a vital role in EANNs.     

Urban Runoff Quality Characterization and Load Estimation in Saskatoon, Canada

The improvement in the effluent quality of the treated sanitary sewage entering the South Saskatchewan River at Saskatoon, Canada, and the impending change in provincial legislation governing urban runoff, provided the impetus for Saskatchewan Environment to initiate the stormwater runoff quality study reported in this paper. Among others, the study involved a field program for characterizing the urban runoff water quality from four catchments, each representing a different type of land use. Both a site mean concentration approach and a multiple variable regression analysis approach were used to quantify the pollutant load contained within the runoff. Thereafter, using the runoff water quality characterizations developed in the study, rainfall–runoff pollutant loads from the entire city were estimated and compared with two local point sources to the receiving stream. On the basis of this analysis, it was found that urban runoff contributes more total suspended solids and total Kjeldahl nitrogen load, similar chemical oxygen demand load, and slightly less total phosphorus load than the two local point sources.     

PCC Airfield Pavement Response during Thaw-Weakening Periods

A field study was performed at two regional airports in Wisconsin during spring thaw to determine its effects on portland cement concrete (PCC) airport pavements. This study was part of a research program to model the performance of airfield pavements for the Federal Aviation Administration. Subsurface temperature and falling weight deflection measurements of the pavement structures were taken at both airports and used to calculate the frost penetration depths, the changes in bearing capacity, and the joint and load transfer efficiencies. This paper summarizes the findings of this study and includes several relationships between various engineering properties of the subsurface layers below the PCC layer, along with a procedure for evaluating pavement performance using falling weight deflection data for PCC pavements during spring thaw.