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.     

Stable Isotopes,Chronology, and Bayesian Models for the Viking Archaeology of North-East Iceland

This paper reviews the results of a long-term research project that used stable isotope analyses (δ¹³C, δ¹⁵N, δ³⁴S) and Bayesian mixing models to better model the chronology for a presumed Viking Age cemetery at Hofstaðir, near Lake Mývatn in north-east Iceland. δ¹³C and radiocarbon dating indicated that many of the individuals consumed a large amount of marine protein, which results in a marine reservoir effect (MRE), making ages older than expected. In addition to the MRE, geological activity in the region has the potential to introduce massive quantities of radioactive ‘dead’ carbon into the freshwater system, resulting in a very large freshwater reservoir effect (FRE) that can offset radiocarbon ages on the order of a few thousand years. The radiocarbon dates of organisms that derive an unknown proportion of their carbon from both marine and freshwater reservoirs are extremely difficult to ‘correct’, or, more appropriately, model. The research not only highlights the complexities of dealing with multiple reservoirs, but also how important it is to develop models that are temporally and geographically relevant to the site under study. Finally, it shows how this data can be used to inform the development of chronological models for refining the dating for archaeological activity.     

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.     

About time: age,period, and cohort effects on support for Quebec sovereignty

Can age, period and cohort effects help explain support for Quebec sovereignty? Previous work on this question has focused mostly on the effects of age and cohort. We contribute to this debate by adding a period perspective. As such, our study is the first to investigate the impact of age, cohort and period effects in a single study of opinion towards sovereignty in Quebec. We take advantage of an original dataset that includes survey data collected between 1985 and 2012. We use these data to examine the impact of age, birth year and survey year on support for this constitutional option among francophone Quebeckers. Our results are in line with previous work: we show that younger Quebeckers are more likely to support sovereignty, and that some cohorts – namely, respondents born between 1945 and 1959 – are also more likely to favour this option. Perhaps more surprisingly, we find that specific events are comparatively the most important factor to explain fluctuations in Quebeckers' attitudes towards sovereignty.     

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.     

Factor Decomposition of Rural Income Inequalities in China

A Chinese geographer explores changes in inter-provincial rural income inequality in China since the late-1970s economic reforms by decomposing it into different component factors based on the Gini index (more specifically, into contributions by different income sources: wages, household operations, properties, and transfers). The influence of each factor on inequality changes is further decomposed into its structure effects and its real inequality effects. Quantitative analysis then makes it possible to determine the relative influence of each component on changes in rural provincial inequality over time.     

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.     

港口经济及其地域空间作用:对鹿特丹港的案例研究

港口经济在国民经济中起着越来越重要的作用,面临全球化竞争的挑战,借鉴国外港口经济的经验对我国三角洲地区和海港城市的发展具有重要意义。本文将分析荷兰鹿特丹港的港口经济发展,研究港口产业对于港口地区的社会经济带动作用,港口产业的时间演替规律和在港口产业带动下的港口地区地域空间扩展规律。