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.     

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.     

The in situ preservation of archaeological remains: using lysimeters to assess the impacts of saturation and seasonality

Recent research has studied the effects of seasonal variability on waterlogged burial environments. In a new approach to the study of archaeological contexts, the use of controlled laboratory conditions via lysimeters has enabled new insights into the nature of short term fluctuations in saturation, and the impact that these can have on burial contexts. In addition, the protocols used have facilitated interesting insights into burial environments and the way in which fluctuations in saturation and seasonality can impact on the contained organic components within them.     

基于电阻率成像法的莫高108窟墙体内水盐运移过程分析

非均质的砂砾石层是莫高窟壁画的主要墙体,但砂砾石层的非均质性如何在水盐运移过程中发挥作用却还不清楚。为此,通过在108窟西壁面上1 m×1 m和2 m×2 m范围的三维高密度电阻率成像监测,发现在这些区域上,墙体电阻率的空间分布都是非均匀的,低阻值区域在空间位置、大小和形状上都会随时间而变化。这明确说明在构成墙体的非均质砂砾石层内存在着重要的水分饱和与非饱和过程(再分配过程),正是这一不断重复的饱和与非饱和过程促进了墙体内水分的运移和盐分在一些特定区域的聚集。研究成果对全面认识莫高窟墙体内的水盐运移机理,减轻和防治壁画盐害都具有重要意义。     

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.     

前剂量饱和指数法测定瓷器的热释光年代

用前剂量饱和指数法测定39件历代瓷器的热释光年代。结果表明,热释光年代与考古年代在一个标准偏差(±1σ)为29％以内的一致性非常良好。这样的误差在瓷器年代测定中是可以接受的。     

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。