Reduced fine sediment flux and channel change in response to the managed diversion of an upland river channel

This paper describes the implementation of a novel mitigation approach and subsequent adaptive management, designed to reduce the transfer of fine sediment (< 2 mm) in Glaisdale Beck, a small, predominantly upland catchment in the UK. Hydro-meteorological and suspended sediment data sets are collected over a 2-year period spanning pre- and post-diversion periods in order to assess the impact of the channel reconfiguration scheme on the fluvial suspended sediment dynamics. Analysis of the river response demonstrates that the fluvial sediment system has become more restrictive with reduced fine sediment transfer. This is characterized by reductions in flow-weighted mean suspended sediment concentrations from 77.93 mg L−1 prior to mitigation, to 74.36 mg L−1 following the diversion. A Mann–Whitney U test found statistically significant differences (p < 0.001) between the pre- and post-monitoring median suspended sediment concentrations (SSCs). Whilst application of one-way analysis of covariance (ANCOVA) on the coefficients of sediment rating curves developed before and after the diversion found statistically significant differences (p < 0.001), with both Loga and b coefficients becoming smaller following the diversion. Non-parametric analysis indicates a reduction in residuals through time (p < 0.001), with the developed LOWESS model over-predicting sediment concentrations as the channel stabilizes. However, the channel is continuing to adjust to the reconfigured morphology, with evidence of a headward propagating knickpoint which has migrated 120 m at an exponentially decreasing rate over the last 7 years since diversion. The study demonstrates that channel reconfiguration can be effective in mitigating fine sediment flux in headwater streams but the full value of this may take many years to achieve whilst the fluvial system slowly readjusts

WMTrace : a lightweight memory allocation tracker and analysis framework

The diverging gap between processor and memory performance has been a well discussed aspect of computer architecture literature for some years. The use of multi-core processor designs has, however, brought new problems to the design of memory architectures - increased core density without matched improvement in memory capacity is reduc- ing the available memory per parallel process. Multiple cores accessing memory simultaneously degrades performance as a result of resource con- tention for memory channels and physical DIMMs. These issues combine to ensure that memory remains an on-going challenge in the design of parallel algorithms which scale. In this paper we present WMTrace, a lightweight tool to trace and analyse memory allocation events in parallel applications. This tool is able to dynamically link to pre-existing application binaries requiring no source code modification or recompilation. A post-execution analysis stage enables in-depth analysis of traces to be performed allowing memory allocations to be analysed by time, size or function. The second half of this paper features a case study in which we apply WMTrace to five parallel scientific applications and benchmarks, demonstrating its effectiveness at recording high-water mark memory consumption as well as memory use per-function over time. An in-depth analysis is provided for an unstructured mesh benchmark which reveals significant memory allocation imbalance across its participating processes

Entrepreneurial decision-making in internationalization: propositions from mid-size firms

Research into international entrepreneurship tends to focus on new ventures rather than larger established firms. Few studies have considered why an entrepreneurial manager in an established firm is motivated to undertake international market entry. Propositions relating to factors motivating the international market entry decision of entrepreneurial managers in mid-sized firms are created and evaluated through in-depth interviews with entrepreneurial managers. We find contrary to extant theory that cultural context, industry environment and resource constraints do not motivate or hinder an entrepreneurial manager's decision to internationalize. Rather, the entrepreneurial manager's connection with the customer, tacit knowledge and vision and product-service complexity are the strongest influences on the decision to internationalize, which is moderated by the strength of the business case and resource-based risk tolerance. This implies a much greater strategic approach by entrepreneurial managers than typically portrayed in current literature. Our research provides researchers with grounded propositions for further empirical testing

The development of a theoretical framework for the internationalization process of fast growth medium-sized firms in Europe

The experience of the author and a review of the literature identifies a number of possible limitations in current theories of internationalization. Existing theories can be broadly classified under the headings of either "stage school" or contingency theories. There appears to have been little research on the interface between the two theoretical approaches, nor on the dynamism of the internationalization process within an individual firm. While scholars challenge the current theory, few have attempted to develop or propose alternative theories. Therefore, the central aim and contribution of this doctoral research has been to develop a theoretical framework from the literature, evaluated in an empirical study of European firms. The research and theoretical development, whilst exploratory, suggests that the internationalization process of firms is contingent on exogenous and endogenous influences. These influences are dynamic, complex and vary according to the specific contexts used in the research. The contingency contexts are summarized here as: The industry and country environment in which the organization operates; the mindset of the entrepreneur decision-maker(s); the nature of the product, the market demographics, and the mindset and nature of the seller and buying organization. The results indicate that the theoretical framework is rigorous enough to demonstrate the variety in the internationalization processes of the firms in the study. The findings are, that whilst there are some common processes and patterns among the firms in the study, there are variations, explained by the contingency theory and contexts in which the firms operate. Previous research has neglected specific contexts as important factors in the internationalization process. The thesis addresses this gap in the research by developing the theory in the context of specific sectors (electronics, software and metal-mechanical) countries (UK, Germany, France and Italy), firm size (medium-sized) and fast growth.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Use of spatially distributed time-integrated sediment sampling networks and distributed fine sediment modelling to inform catchment management

Under the EU Water Framework Directive, suspended sediment is omitted from environmental quality standards and compliance targets. This omission is partly explained by difficulties in assessing the complex dose-response of ecological communities. But equally, it is hindered by a lack of spatially distributed estimates of suspended sediment variability across catchments. In this paper, we demonstrate the inability of traditional, discrete sampling campaigns for assessing exposure to fine sediment. Sampling frequencies based on Environmental Quality Standard protocols, whilst reflecting typical manual sampling constraints, are unable to determine the magnitude of sediment exposure with an acceptable level of precision. Deviations from actual concentrations range between −35 and +20% based on the interquartile range of simulations. As an alternative, we assess the value of low-cost, suspended sediment sampling networks for quantifying suspended sediment transfer (SST). In this study of the 362 km2 upland Esk catchment we observe that spatial patterns of sediment flux are consistent over the two year monitoring period across a network of 17 monitoring sites. This enables the key contributing sub-catchments of Butter Beck (SST: 1141 t km2 yr−1) and Glaisdale Beck (SST: 841 t km2 yr−1) to be identified. The time-integrated samplers offer a feasible alternative to traditional infrequent and discrete sampling approaches for assessing spatio-temporal changes in contamination. In conjunction with a spatially distributed diffuse pollution model (SCIMAP), time-integrated sediment sampling is an effective means of identifying critical sediment source areas in the catchment, which can better inform sediment management strategies for pollution prevention and control

1881 Proceedings of the Ecumenical Methodist Conference

https://place.asburyseminary.edu/wmcproceedings/1007/thumbnail.jp

Understanding the evolution of native pinewoods in Scotland will benefit their future management and conservation

Scots pine (Pinus sylvestris L.) is a foundation species in Scottish highland forests and a national icon. Due to heavy exploitation, the current native pinewood coverage represents a small fraction of the postglacial maximum. To reverse this decline, various schemes have been initiated to promote planting of new and expansion of old pinewoods. This includes the designation of seed zones for control of the remaining genetic resources. The zoning was based mainly on biochemical similarity among pinewoods but, by definition, neutral molecular markers do not reflect local phenotypic adaptation. Environmental variation within Scotland is substantial and it is not yet clear to what extent this has shaped patterns of adaptive differentiation among Scottish populations. Systematic, rangewide common-environment trials can provide insights into the evolution of the native pinewoods, indicating how environment has influenced phenotypic variation and how variation is maintained. Careful design of such experiments can also provide data on the history and connectivity among populations, by molecular marker analysis. Together, phenotypic and molecular datasets from such trials can provide a robust basis for refining seed transfer guidelines for Scots pine in Scotland and should form the scientific basis for conservation action on this nationally important habitat

Abiotic and spatiotemporal factors affect activity of European bat species and have implications for detectability for acoustic surveys

Bat activity surveys are essential in the contexts of scientific research, conservation, assessment of ecosystem health, monitoring progress towards sustainable development goals, and legislative compliance in development and infrastructure construction. However, environmental conditions have the potential to influence bat activity and, in turn, their detectability in acoustic surveys. Here we use 3242 hours of acoustic survey data from 323 nights of bat monitoring at 14 sites over a 4-year period to explore the influence of spatiotemporal factors, lunar phase and weather conditions on bat activity. All spatiotemporal and abiotic factors analysed (site, hour post sunset, length of night, duration of moonlight, temperature, rain, wind and cloud cover) contributed to the optimal multivariate model for at least one bat species/genus; all factors except cloud cover and temperature were significant in the optimal model for total bat activity. However, there were notable species-specific differences. Among the key findings were differences between Pipistrellus species, with periods of rainfall being negatively related to soprano pipistrelle Pipistrellus pygmaeus registrations but not those of common pipistrelle Pipistrellus pipistrellus. In addition, overcast conditions showed a strong positive relationship with the number of Myotis registrations while duration of moonlight was positively correlated with common pipistrelle. Temperature was only important for Nyctalus species. These findings demonstrate that understanding the effect multifaceted and interlinked environmental factors on the activity of different bat species is a vital step in developing maximally effective survey protocols, which, in turn, will improve the reliability of conservation and planning decisions underpinned by survey data

High-frequency monitoring of nitrogen and phosphorus response in three rural catchments to the end of the 2011–2012 drought in England

This paper uses high-frequency bankside measurements from three catchments selected as part of the UK government-funded Demonstration Test Catchments (DTC) project. We compare the hydrological and hydrochemical patterns during the water year 2011–2012 from the Wylye tributary of the River Avon with mixed land use, the Blackwater tributary of the River Wensum with arable land use and the Newby Beck tributary of the River Eden with grassland land use. The beginning of the hydrological year was unusually dry and all three catchments were in states of drought. A sudden change to a wet summer occurred in April 2012 when a heavy rainfall event affected all three catchments. The year-long time series and the individual storm responses captured by in situ nutrient measurements of nitrate and phosphorus (total phosphorus and total reactive phosphorus) concentrations at each site reveal different pollutant sources and pathways operating in each catchment. Large storm-induced nutrient transfers of nitrogen and or phosphorus to each stream were recorded at all three sites during the late April rainfall event. Hysteresis loops suggested transport-limited delivery of nitrate in the Blackwater and of total phosphorus in the Wylye and Newby Beck, which was thought to be exacerbated by the dry antecedent conditions prior to the storm. The high rate of nutrient transport in each system highlights the scale of the challenges faced by environmental managers when designing mitigation measures to reduce the flux of nutrients to rivers from diffuse agricultural sources. It also highlights the scale of the challenge in adapting to future extreme weather events under a changing climate