Changes in stream channel morphology at tributary junctions,Lower Hunter Valley,New South Wales

Many empirically derived models of downstream changes in channel form are based on the concept of hydraulic geometry, whereby changes in channel morphological variables are related by a continuous power function to increasing discharge or its surrogate. However, changes in discharge throughout a drainage basin are normally concentrated at the junctions of stream channels. At junctions, the relationship between discharge and channel morphology is discontinuous. Some Lower Hunter Valley stream channels were surveyed upstream and downstream of tributary junctions. While significant regional downstream relationships were established, consistent trends at tributary junctions were not apparent from the data. It is possible that considerable scatter evident in ratios of change on either side of each junction was due to local within-site variability. In addition, the relative timing of discharge inputs and the nature of introduced sediment loads could be important in determining the magnitude and direction of channel change at tributary junctions. Interrelated changes in cross-sectional, profile and planform variables may be expected below junctions. The resultant channel morphology, in terms of these variables, might not be wholly determinate.     

History and Effects of Channelisation on the Latrobe River,Victoria

Channel changes on the lower Latrobe River since the late 1800s include a 25 per cent reduction in channel length due to artificial meander cutoffs, increases in mean channel width, increased channel instability and incision of up to 1.05 m. Hydraulic changes at the Rosedale gauge include increases in bankfull flow velocity and a 67 per cent increase in channel capacity, resulting in a threefold reduction of over-bank flow duration. The extensive channelisation works have reduced the frequency of minor flooding and the period offloodplain inundation, but these and other human impacts have severely degraded the stream environment.     

A NOTE ON THE DIFFERENTIAL THERMAL ANALYSIS OF ARCHAEOLOGICAL CERAMICS

Evidence is presented that the clay in ancient ware fired at a temperature below 700–800°C becomes rehydrated over the millennia, such that it behaves somewhat like an unfired clay, rendering DTA a useful tool in identifying the clay minerals present. More recent samples can be artificially rehydrated by heating in a steam autoclave.     

Domestic abuse and the public/private divide in the British military

Divisions between the social spheres of public and private are always fluid, mutually constitutive, and politically and socially formulated. Within the British military, such divisions are further framed through the needs of operational effectiveness. In the pursuit of operational effectiveness the public/private divide functions at times as porous, in large part through the military's provision of services such as housing, welfare and policing to personnel and their families and through the notion of a close-knit military community, and at others as firm, bolstering operational effectiveness through recourse to militarised ideas of the private sphere as the fixed space of hearth, home and femininity which is to be protected by military force. This article employs narratives of domestic abuse as a window through which to analyse enactments of the public/private divide in the British military. The analysis draws upon interview participants' experiences of abuse and of help-seeking to illustrate the complex and fluid ways in which the prioritisation of operational effectiveness frames and delimits the public and the private within the contemporary British military in relation to domestic abuse. The impacts of this upon victim-survivors' help-seeking experiences are discussed.     

Evaluation of soluble benzene migration in the Uinta Basin

Field sampling and mathematical modeling are used to study the long‐distance transport and attenuation of petroleum‐derived benzene in the Uinta Basin, Utah. Benzene concentration was measured from oil and oil field formation waters of the Altamont‐Bluebell and Pariette Bench oil fields in the basin. It was also measured from springs located in the regional groundwater discharge areas, hydraulically down‐gradient from the oil fields sampled. The average benzene concentration in oils and co‐produced waters is 1946 and 4.9 ppm at the Altamont‐Bluebell field and 1533 and 0.6 ppm at the Pariette Bench field, respectively. Benzene concentration is below the detection limit in all springs sampled. Mathematical models are constructed along a north–south trending transect across the basin through both fields. The models represent groundwater flow, heat transfer and advective/dispersive benzene transport in the basin, as well as benzene diffusion within the oil reservoirs. The coupled groundwater flow and heat transfer model is calibrated using available thermal and hydrologic data. We were able to reproduce the observed excess fluid pressure within the lower Green River Formation and the observed convective temperature anomalies across the northern basin. Using the computed best‐fit flow and temperature, the coupled transport model simulates water washing of benzene from the oil reservoirs. Without the effect of benzene attenuation, dissolved benzene reaches the regional groundwater discharge areas in measurable concentration (>0.01 ppm); with attenuation, benzene concentration diminishes to below the detection limit within 1–4 km from the reservoirs. Attenuation also controls the amount of water washing over time. In general, models that represent benzene attenuation in the basin produce results more consistent with field observations.     

Thermal springs and heat flow in North America

Thermal springs are commonly thought to be an indicator of geothermal resource potential. However, there have been few analyses of the relationship between thermal springs and the underlying thermal regime. An examination of temperature and discharge rates for a large database of thermal springs in North America demonstrates that there is not a simple relationship between these measurements made at the surface and subsurface heat flow. Hydrogeological factors appear to exert strong controls on the temperature and discharge at these springs and should be carefully considered in geothermal resource assessments.     

Integrating Transportation Network and Regional Economic Models to Estimate the Costs of a Large Urban Earthquake

In this paper we summarize an integrated, operational model of losses due to earthquake impacts on transportation and industrial capacity, and how these losses affect the metropolitan economy. The procedure advances the information provided by transportation and activity system analysis techniques in ways that help capture the most important ecomonic implications of earthquakes. Network costs and origin-destination requirements are modeled endogenously and consistently. Indirect and induced losses associated with direct impacts on transportation and industrial capacity are distributed across zones and ecomonic sectors. Preliminary results are summarized for a magnitude 7.1 earthquake on the Elysian Park blind thrust fault in Los Angeles.     

THERMOLUMINESCENT DATING OF COLOMBIAN POTTERY IN THE YOTOCO STYLE

Two contexts from the Colombian sites, Yotoco Ferry and Moralba, had been linked by archaeological similarities in pottery style, and dated by association with ware from other sites at circaa.d. 1000. However, radiocarbon dating of those contexts set Moralba at circa 800 b.c. , some 2000 yr older than Yotoco Ferry. Thermoluminescent dating of pottery from Yotoco Ferry dated it at circaa.d. 900, and pottery from Moralba was dated at circaa.d. 870. In addition a metal-smelting pottery crucible, thought to be prehispanic, was studied by thermoluminescence and dated, on the contrary, at less than 120 yr old.     

Military command in the last decade

On 11 September 2010, the United States commemorated the ninth anniversary of the 9/11 attacks. In those nine years, British forces have been engaged in military operations of unexpected location, intensity, scale and duration. While the performance of British troops has been repeatedly praised on these operations, there has been growing disquiet among commentators and, indeed, among the military establishment itself about the conduct of these campaigns. Specifically, the issue of British military command has come under increasing scrutiny. This article examines command frictions at the strategic and operational levels and seeks to provide a sociological explanation of these difficulties. It claims that British commanders have failed to identify a coherent strategy over the past decade while in‐theatre operational command has often been characterized by an ad hoc‐ery, incoherence and inconsistency. The article suggests that a ‘laissez faire’ command culture has been evident at strategic and operational levels. While individual mistakes may not be irrelevant, the article explores the way in which this command culture may be a product of institutional pressures within defence and, above all, a product of inter‐service rivalry. However, the laissez faire system of command in the armed forces may also be a reflection of much deeper cultural presumptions and preferences within British professional society itself which has always had a strong tendency towards pragmatism, decentralization and shorttermism. The article concludes by offering some suggestions as to how military command might be reformed in light of its potentially profound cultural origins.     

HIGH‐RESOLUTION (PIXE) ANALYSES OF CARBONATE DEPOSITS IN A ROMAN AQUEDUCT (FRÉJUS,SE FRANCE): IMPLICATIONS FOR THE STUDY OF PALAEOHYDROLOGICAL VARIABILITY AND WATER RESOURCES MANAGEMENT IN SOUTHERN GAUL DURING THE ROMAN PERIOD*

Urban water was supplied to the Roman city of Forum Julii (Fréjus, southeastern France) for at least 200 years by a 39.4 km long aqueduct, operating in ad 50. Two perennial springs were successively collected, the Foux and the Siagnole, located at the outlet of Triassic and Jurassic karstic reservoirs, respectively. In this study, we performed high‐resolution PIXE (Particle‐Induced X‐ray Emission) measurements of Ca, Si, Fe and Sr concentrations on selected cross‐sections of laminated carbonate sampled along the sidewalls, before and after the connection of the two collection channels. Seasonal variations of water composition, suspended sediment load and discharge are recorded by alternating clear and dark layers, and can be traced by their Sr and Fe contents. On the basis of an annual bimodal high‐discharge regime for the two karstic reservoirs, the concentration measurements allow the derivation of a chronological record (117.5 years) of water supply and maintenance activities for a part of the operational period of the aqueduct. The water level in the channel was mainly controlled by the extent of carbonate deposition and by dredging, repair and maintenance operations rather than by the past hydrological regime of the two springs.     

Spring temperatures in the Sagehen Basin, Sierra Nevada, CA: implications for heat flow and groundwater circulation

Heat flow in the Sierra Nevada, CA, is low despite its young geologic age. We investigate the possibility that advective heat transport by groundwater flow leads to an underestimate of heat flow in the Sierras based purely on borehole measurements. Using temperature and discharge measurements at springs in Sagehen Basin, we find that groundwater removes the equivalent of approximately 20–40 mW m⁻² of geothermal heat from the basin. This is comparable with other heat flow measurements in the region and indicates that, in this basin, at least, groundwater does transport a significant amount of geothermal heat within the basin. Additionally, we use estimates of the mean residence time of water discharged at the springs along with hourly temperature records in springs to provide constraints on groundwater flow depths within the basin. An analytical model based on these constraints indicates that the heat removed by groundwater may represent 20% to >90% of the total heat flow in the basin. Without better constraints on the regional hydrogeology and the depth of circulation, we cannot determine whether the heat discharged at the springs represents a change in the mode of heat transfer, i.e. from conduction to advection at shallow depths (<100 m) or whether this is a component of heat transfer that should be added to measured conductive values. If the latter is true, and Sagehen Basin is representative of the Sierras, basal heat flow in the Sierra Nevada may be higher than previously thought.     

A Correlation Between Radiation and Health Problems in Belarus'?

An international authority on the effects of the Chernobyl' nuclear power station accident surveys the emerging controversy over the severity of its impact upon the health of the population of Belarus', the republic most seriously affected by the radiation release. A broad spectrum of assessments is analyzed, ranging from those which are inclined to attribute negligible health impacts to the disaster to those citing dramatic increases in the incidence of thyroid cancer among children in the most severely impacted oblasts as a possible precursor of significant long-term health risks to the population at large. 1 map, 1 table, 17 references.     

Response of Alum Rock springs to the October 30, 2007 Alum Rock earthquake and implications for the origin of increased discharge after earthquakes

The origins of increased stream flow and spring discharge following earthquakes have been the subject of controversy, in large part because there are many models to explain observations and few measurements suitable for distinguishing between hypotheses. On October 30, 2007 a magnitude 5.5 earthquake occurred near the Alum Rock springs, California, USA. Within a day we documented a several‐fold increase in discharge. Over the following year, we have monitored a gradual return towards pre‐earthquake properties, but for the largest springs there appears to be a permanent increase in discharge. The Alum Rock springs discharge waters that are a mixture between modern (shallow) meteoric water and old (deep) connate waters expelled by regional transpression. After the earthquake, there was a small and temporary decrease in the fraction of connate water in the largest springs. Accompanying this geochemical change was a small (1–2°C) temperature decrease. Combined with the rapid response, this implies that the increased discharge has a shallow origin. Increased discharge at these springs occurs both for earthquakes that cause static volumetric expansion and for those that cause contraction, supporting models in which dynamic strains are responsible for the subsurface changes that cause flow to increase. We make a quantitative comparison between the observed changes and model predictions for three types of models: (i) a permanent increase in permeability; (ii) an increase in permeability followed by a gradual decrease to its pre‐earthquake value; and (iii) an increase of hydraulic head in the groundwater system discharging at the springs. We show that models in which the permeability of the fracture system feeding the springs increases after the earthquake are in general consistent with the changes in discharge. The postseismic decrease in discharge could either reflect the groundwater system adjusting to the new, higher permeability or a gradual return of permeability to pre‐earthquake values; the available data do not allow us to distinguish between these two scenarios. However, the response of these springs to another earthquake will provide critical constraints on the changes that occur in the subsurface and should permit a test of all three types of models.     

THE ACTUAL AND PERCEIVED EFFECTS OF FLOODPLAIN LAND-USE REGULATIONS ON RESIDENTIAL PROPERTY VALUES IN LONDON, ONTARIO

The impacts associated with floodplain management adjustments should be understood. This paper addresses this need by describing the perceived and actual impacts floodplain regulations have had on residential land values in a portion of London, Ontario. The institutional arrangements for floodplain regulation and the actual practice of regulation in the City of London for the period 1978–1989 are described. Actual impacts on land values were determined through use of a geographical matching technique based on data obtained from mls sources and permit data available at the Upper Thames River Conservation Authority office. Perceptual data were acquired from a questionnaire survey of floodplain landowners. Findings indicate that most residents perceived that no impact on land values was associated with floodplain regulations. This view was supported by the analysis of actual home transactions     

Construction and Interpretation of a 60‐year Flow Record for the river Tay at Kenmore

The backward extension of a river flow record for the River Tay, based on daily water level observations from 1937–76, has created the third‐longest sensibly continuous daily flow record for any Scottish river based on direct observations. The paper describes the derivation of the record, and assesses the variability of the Tay discharge over the 60‐year period covered. Unprecedented winter, spring and flood flows in the late 1980s/1990s are reported, in the context of improving the understanding of hydroclimatic variability.     

Geophysical and geochemical evidence of large scale fluid flow within shallow sediments in the eastern Gulf of Mexico,offshore Louisiana

We analyse the fluid flow regime within sediments on the Eastern levee of the modern Mississippi Canyon using 3D seismic data and downhole logging data acquired at Sites U1322 and U1324 during the 2005 Integrated Ocean Drilling Program (IODP) Expedition 308 in the Gulf of Mexico. Sulphate and methane concentrations in pore water show that sulphate–methane transition zone, at 74 and 94 m below seafloor, are amongst the deepest ever found in a sedimentary basin. This is in part due to a basinward fluid flow in a buried turbiditic channel (Blue Unit, 1000 mbsf), which separates sedimentary compartments located below and above this unit, preventing normal upward methane flux to the seafloor. Overpressure in the lower compartment leads to episodic and focused fluid migration through deep conduits that bypass the upper compartment, forming mud volcanoes at the seabed. This may also favour seawater circulation and we interpret the deep sulphate–methane transition zones as a result of high downward sulphate fluxes coming from seawater that are about 5–10 times above those measured in other basins. The results show that geochemical reactions within shallow sediments are dominated by seawater downwelling in the Mars‐Ursa basin, compared to other basins in which the upward fluid flux is controlling methane‐related reactions. This has implications for the occurrence of gas hydrates in the subsurface and is evidence of the active connection between buried sediments and the water column.     

Salt tectonics and shallow subseafloor fluid convection: models of coupled fluid‐heat‐salt transport

Thermohaline convection associated with salt domes has the potential to drive significant fluid flow and mass and heat transport in continental margins, but previous studies of fluid flow associated with salt structures have focused on continental settings or deep flow systems of importance to petroleum exploration. Motivated by recent geophysical and geochemical observations that suggest a convective pattern to near‐seafloor pore fluid flow in the northern Gulf of Mexico (GoMex), we devise numerical models that fully couple thermal and chemical processes to quantify the effects of salt geometry and seafloor relief on fluid flow beneath the seafloor. Steady‐state models that ignore halite dissolution demonstrate that seafloor relief plays an important role in the evolution of shallow geothermal convection cells and that salt at depth can contribute a thermal component to this convection. The inclusion of faults causes significant, but highly localized, increases in flow rates at seafloor discharge zones. Transient models that include halite dissolution show the evolution of flow during brine formation from early salt‐driven convection to later geothermal convection, characteristics of which are controlled by the interplay of seafloor relief and salt geometry. Predicted flow rates are on the order of a few millimeters per year or less for homogeneous sediments with a permeability of 10^?15 m², comparable to compaction‐driven flow rates. Sediment permeabilities likely fall below 10^?15 m² at depth in the GoMex basin, but such thermohaline convection can drive pervasive mass transport across the seafloor, affecting sediment diagenesis in shallow sediments. In more permeable settings, such flow could affect methane hydrate stability, seafloor chemosynthetic communities, and the longevity of fluid seeps.     

Three Common Machine Learning Algorithms Neither Enhance Prediction Accuracy Nor Reduce Spatial Autocorrelation in Residuals: An Analysis of Twenty-five Socioeconomic Data Sets

Machine learning (ML) is being applied in an increasing volume of geographical research. However, the aspects of spatial autocorrelation (SAC) in the residuals produced by ML models have been understudied compared to the benefit of ML, namely, reduction of prediction errors. In this study, we examined the relationship between predictive accuracy and the reduction in the residual SAC for 597 variables from 25 geographical socio-economic data sets using spatial and nonspatial cross-validation of three ML algorithms such as random forests, support vector machine, and artificial neural network (ANN) to provide an extensive empirical diagnosis—but not a definitive theory—of the relationship between SAC and ML. Our results highlighted that the ML algorithms with tuned hyperparameters yielded marginal predictive accuracy gains and the minimal decreases in residual SAC. ANN revealed lower accuracy and higher reduction in the residual SAC than others. This implies ML algorithms in geographical research in socio-economic domains would not always result in higher prediction accuracy. We suggest that ML in geographical research should be cautiously employed when the main objective is related to the residual SAC. We also showed that spatial cross-validation neither improves predictive accuracy substantially nor reduce the residual SAC effectively.     

旅游影响生成机制探析

本文从系统论的角度,探讨了旅游对目的地影响的生成机制问题。分析了旅游影响三大因子模块：旅游影响动力因子模块,即旅游流系统;旅游影响应力因子模块,即旅游目的地系统;旅游影响规范因子模块,即旅游制度创新系统。旅游流系统是通过旅游流各因子的各种行为对旅游影响产生驱动作用,从而使旅游目的地系统各旅游利益相关者产生响应行为,旅游制度创新系统通过规范各旅游利益相关者的行为来达到对旅游影响的调适和优化。这三大旅游影响因子模块是在5种旅游影响场：经济场、信息场、心理场、引力场和生态场的作用下相互影响、相互作用,以及通过旅游影响的不断反馈而生成的,从而得到一个旅游影响生成机制模型。     

Rhetoric versus reality in the rise of policing in UN peace operations: ‘More blue,less green’?

ABSTRACT

United Nations police (UNPOL) have become increasingly important to operational effectiveness of peace operations. For some time, their contribution to re-establishing the rule of law in conflict-affected states has been seen as a cornerstone for building sustainable peace and enabling mission exit strategies. In a departure from traditional peacekeeping and post-conflict assistance, recent years have seen UN peace operations directed to stabilise countries and protect civilians in the context of on-going violent conflict. As a result, UNPOL have had to undertake a range of expanded tasks, exacerbating long-standing challenges and producing new impediments to their operational effectiveness. At the same time, a ‘pragmatic turn’ is generating increased interest in more police-centric concepts of peacekeeping as a possible alternative to today’s expensive and military-focused peace operations. Drawing on extensive fieldwork in multiple peace operations and at UN headquarters, this article examines the changing roles of UNPOL in a new breed of UN peace operations, identifies the major associated challenges and proposes a series of recommendations for overcoming them. It argues that if police are to respond to unfolding challenges while becoming more central to peacekeeping outcomes, then significant reforms and further research into their impacts will be required.