Development of Trigger Levels to Assess Catchment Disturbance on Stream Suspended Sediment Loads in the Magela Creek Catchment,Northern Territory,Australia

Trigger levels for fine suspended sediment (FSS) load in streams are required to identify rainfall-runoff events that have significantly elevated FSS loads, compared with expected background loads, as a result of catchment disturbance. Stream FSS load data collected in the mine-impacted Magela Creek catchment in the wet-dry tropics were used to derive water quality management trigger levels for two approaches – a Before-After-Control-Impact Paired difference design (BACIP) and a regression relationship between observed FSS load and corresponding event discharge characteristics. The results indicate that both the BACIP and regression relationship approaches behave similarly, with similar FSS load events elevated above trigger levels. Notwithstanding this, it is recommended that in order to reliably assess the location and magnitude of a catchment disturbance on FSS load, a combination of BACIP and regression relationship approaches must be adopted. In this study, an event with a FSS load above trigger levels associated with both BACIP and the regression relationship fitted for the downstream site is considered to be significantly elevated as a result of a disturbance within the mine-impacted region. While this technique cannot conclusively determine whether the cause of the disturbance is mine-related or natural (such as fire or bank erosion), it is an efficient statistical method of identifying events that warrant further investigation and management action, if required.     

基于快递物流测度的区域流动空间特征——以江苏省为例

在信息技术推动下,流动空间作为新时期的新空间形式在带来时空压缩效应的同时不断地强化着区域城市间联系,推动着社会经济资源的城际流通。快递物流是互联网交易的虚拟流与快速交通实体流交互产生的物质流动,其代表了流动空间的虚实二元性,是研究流动空间网络特征的有效切入点。以江苏十三个城市为研究区域,以六家物流公司的网站数据为数据来源,采用权重分析法和重力模型方法建立起区域城市的快递物流水平、城市间流动空间连接度及城市快递物流总体评价等三项指标,结合区域流动空间的指标分析发现区域流动空间具有网络一体化、去中心化、扁平化、等级化及点轴式等五大特征,基于流动空间的可视化研究发现江苏省区域城市间关系显示出了一个具有等级特征的多中心扁平化点轴网络,围绕南京、苏州、徐州的都市圈一体化发展态势成为提高区域流动空间流动能力的重要突破方向。     

Studying Immigrant Policy One Law at a Time

This article shows that, in the study of immigrant integration policy in the U.S. states, it is critical to report data and coding decisions for individual laws. This analysis uses an updated and public database of law‐level decisions, which includes 2,703 legislative actions recorded by the National Conference of State Legislatures from 2005 to 2016. These data are used to estimate models of aggregate state policy activity in a variety of ways: as a single continuum of policy balance versus separate models of welcoming and hostile, lumping all policy subareas together versus analyzing a specific subarea, and lumping all years together in one cross section versus panel analysis. The results in these models differ enough to indicate that reporting codes for individual‐level laws is absolutely essential so that each researcher easily can construct the measure that fits his or her theoretical framework best.     

An investigation of factors determining cycling experience and frequency

A bicycle tourism destination is composed of complexes of different attributes that are crucial for the determination of tourist satisfaction levels. However, the relative impact of sector-specific destination attributes on bicycle touring and leisure cycling experience and frequency has been both poorly understood and studied. This study is an attempt to fill this literature gap by exploring a demand-side perspective on the important contributors of overall satisfaction with cycling experience and the key determinants of cycling frequency. The 28 sector-specific destination attributes were drawn from the relevant literature, and then modified by a panel of industry experts. Using exploratory factor analysis, three destination-specific attribute-level satisfaction factors were identified in descending order of satisfaction degree: ‘provision of signage services,’ ‘provision of safety and emergency services,’ and ‘quality of bicycle routes.’ Among these factors, ‘provision of safety and security services’ and ‘provision of signage services’ were found to be the most important contributors to overall satisfaction. Finally, ‘monthly income’ was proven to be a significant predictor of cycling frequency. This study is of great importance as there is a growing body of evidence that the use of bicycle for leisure, recreation, and tourism is undergoing a resurgence worldwide. The findings of this study may be of interest to scholars in Western countries where bicycle tourism is mature and highly developed and in Asian countries where the sector is at an early stage of development. Since bicycle touring and leisure cycling experience and frequency can be increased by modifying destination marketing and management practices, the government and industry sectors should focus more attention on ensuring the provision of multi-functional grocery and convenience stores along designated bicycle routes, developing an informative and visible signage system for designated bicycle routes, and targeting middle- to high-income bicyclists with diverse bicycle touring and leisure cycling experience options.     

Statistical methods for bioarchaeology: applications of age-adjustment and logistic regression to comparisons of skeletal populations with differing age-structures

Previous studies of patterns of osteoarthritis involvement in prehistoric skeletal populations have been used to suggest differences in lifestyle or subsistence patterns. In spite of the intriguing nature of such studies, inadequate controls for the potential confounding effects of age have made results less secure than they appear. While researchers remain unable to control for the inherent limitations imposed by preservation bias, meaningful advancement could be made in the analysis of these data. Here we propose two methods from epidemiology that would allow more robust comparisons between populations with differing age-structures: age-adjustment and logistic regression. We apply these two methods to previously published data from prehistoric populations of the American Great Basin. In doing so, we are able to discern sex differences in risk for osteoarthritis at the shoulder (beta = −1.82, SE = 0.74, OR = 0.16, 95% CI = 0.04–0.69, p = 0.013), elbow (beta = −2.07, SE = 0.82, OR = 0.13, 95% CI = 0.03–0.63, p = 0.011), and in the foot (beta = −3.11, SE = 1.57, OR = 0.04, 95% CI = 0.00–0.97, p = 0.048), that were not noted in previous analyses of these data. These findings suggest that greater clarity of results and more precise comparisons of risk may be achieved by using these methods. We conclude that further application of these methods to bioarchaeological studies would potentially improve what can be said about prehistoric health patterns and lifeways.     

基于SEA的AGA-SVR节假日客流量预测方法研究

节假日旅游客流量由于游客在短期内大量集中于同一地点、不同节假日休假时间长短、所处季节等不同,呈现复杂非线性特征和明显季节性特点.本文提出一种基于季节指数调整(Seasonal Exponential Adjustment,SEA)的自适应遗传算法(Adaptive Genetic Algorithm,AGA)-支持向量回归 (Support Vector Regression,SVR)预测模型,即基于SEA的AGA-SVR模型,并用国内著名5A级风景区黄山2008~2012年节假日客流量数据对模型进行验证.研究结果表明,基于SEA的AGA-SVR预测模型能够准确处理节假日旅游客流量预测中的非线性和季节性问题,较AGA-SVR和GA-SVR等方法具有更高的预测精度,在旅游预测领域应用前景广阔.     

The estimation of live fish size from archaeological cranial bones of the New Zealand blue cod Parapercis colias

Twenty-four measurements were taken on five of the paired cranial bones and the otoliths of a modern sample of 177 blue cod. Parapercis colias. Regression analysis was performed on these measurements to estimate live fork length and ungutted weight. A number of regression models were examined (linear, logarithmic, exponential and power curve) to work out the optimum estimator for each bone measurement. It was found that live fork length of this species can be estimated with a standard error of less than ±28 mm, and the weight to less than ±140 g. Coefficients are provided for 48 equations linking bone size to live characteristics. This is followed by a study of blue cod from an archaeological site at Waihora in the Chatham Islands. Measurements were made on 8036 archaeological bones with a minimum number of individuals of 2547. It was found that the blue cod catch had near normal characteristics, with a mean fork length of 327 mm and SD of 57 mm. The mean body weight was estimated at 569 g. The usable meat weight represented by these fish is estimated to be 1.0 t. © 1997 John Wiley & Sons, Ltd.     

正规商业与流动商贩的空间分布关系及其影响因素——以北京市朝阳区为例

流动商贩是城市商业的重要组成部分,其空间分布格局与正规商业不相同。本文以正规商业和流动商贩的引力可达性指数,比较两者在同一区位的可达性差异,依此将两者的空间分布关系划分为五种类型,这些类型在空间上呈同心圆、扇形与多核心相结合的分布模式。通过无序多分类logistic回归,发现以人口密度和人口结构为代表的社会力、以国际资本为代表的市场力和具有不同监管强度的政府力均对正规商业与流动商贩的空间分布关系有显著影响。     

日韩东盟8国入境我国旅游与进出口贸易关系的研究

国际旅游与国际贸易是相互联系的,旅游引发贸易、贸易推动旅游。本文在前期研究工作的基础上,提出了一个旅游与贸易互动的三阶段模型,即旅游引发贸易、贸易推动旅游和偏好-容量限制3个阶段。以日韩东盟8国为例,选用1986年-2009年统计数据,分析了8国入境我国旅游与进出口贸易的关系,构建了入境客流量与进口贸易、出口贸易和进出口贸易3组24个推拉方程。在此基础上,以1992年和2002年为分界点,分析了各阶段入境客流量与进口贸易、出口贸易增长率的变化及弧弹性;依据每万人次入境旅游引发的进出口贸易强度,将日韩东盟8国划分为四种类型,分析了近10年来旅游引起进出口贸易强度的变化,为通过旅游拉动贸易或通过贸易推动入境旅游发展提供了科学依据。