178 research outputs found

    A review of the science and logic associated with approach used in the universal soil loss equation family of models

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    Soil erosion caused by rain is a major factor in degrading agricultural land, and agricultural practices that conserve soil should be used to maintain the long-term sustainability of agricultural land. The Universal Soil Loss Equation (USLE) was developed in the 1960s and 1970s to predict the long-term average annual soil loss from sheet and rill erosion on field-sized areas as an aid to making management decisions to conserve soil. The USLE uses six factors to take account of the effects of climate, soil, topography, crops, and crop management, and specific actions designed to conserve soil. Although initially developed as an empirical model based on data from more than 10,000 plot years of data collected in plot experiments in the USA, the selection of the independent factors used in the model was made taking account of scientific understanding of the drivers involved in rainfall erosion. In addition, assumptions and approximations were needed to make an operational model that met the needs of the decision makers at that time. Those needs have changed over time, leading to the development of the Revised USLE (RUSLE) and a second version of that, the Revised USLE, Version 2 (RUSLE2). While the original USLE model was not designed to predict short-term variations in erosion well, these developments have involved more use of conceptualization in order to deal with the time-variant impacts of the drivers involved in rainfall erosion. The USLE family of models is based on the concept that the “unit” plot, a bare fallow area 22.1 m long on a 9% slope gradient with cultivation up and down the slope, provides a physical situation where the effect of climate and soil on rainfall erosion can be determined without the need to consider the impact of the four other factors. The science and logic associated with this approach is reviewed. The manner by which the soil erodibility factor is determined from plot data ensures that the long-term average annual soil loss for the unit plot is predicted well, even when the assumption that event soil loss is directly related to the product of event rainfall energy, and the maximum 30-min intensity is not wholly appropriate. RUSLE2 has a capacity to use CLIGEN, the weather generator used in WEPP, and so can predict soil losses based on individual storms in a similar way to WEPP. Including a direct consideration of runoff in determining event erosivity enhances the ability to predict event soil losses when runoff is known or predicted well, but similar to more process-based models, this ability is offset by the difficulty in predicting runoff well

    Mechanical structures for smart-phone enabled sensing

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    Development of CO2 snow cleaning for in situ cleaning of µCMM stylus tips

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    Contamination adhered to the surface of a µCMM stylus tip compromises the measurement accuracy of the µCMM system, potentially causing dimensional errors that are over ten times larger than the uncertainty of a modern µCMM. In prior work by the authors, the use of a high pressure CO2 gas stream was demonstrated to achieve significant cleaning rate for a range of contaminant without damage to the stylus tip surface. This paper explores the practical challenges of achieving effective stylus tip cleaning in situ on µCMM systems. Two types of snow cleaning approaches were evaluated for their coverage of cleaning, thermal impact and gas flow forces. This work then presents a novel multi-nozzle prototype system using pulsed snow streams to achieve cleaning coverage over the entire stylus tip, and balances forces from the snow streams reducing drag force imparted by the gas stream to levels comparable to the probing force of µCMMs, as well as allowing automated cleaning procedure integrated into a µCMM system

    Prokineticin ligands and receptors are expressed in the human fetal ovary and regulate germ cell expression of COX2

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    CONTEXT: Fetal ovarian development and primordial follicle formation underpin future female fertility. Prokineticin (PROK) ligands regulate cell survival, proliferation and angiogenesis in adult reproductive tissues including the ovary. However, their expression and function during fetal ovarian development remains unclear.OBJECTIVE: To investigate expression and localization of the PROK ligands, receptors and their downstream transcriptional targets in the human fetal ovary.SETTING: This study was conducted at the University of Edinburgh.PARTICIPANTS: Ovaries were collected from 37 morphologically normal human fetuses.DESIGN AND MAIN OUTCOME MEASURES: mRNA and protein expression of PROK ligands and receptors was determined in human fetal ovaries using qRT-PCR, immunoblotting and immunohistochemistry. Functional studies were performed using a human germ tumour cell line (TCam-2) stably transfected with PROKR1.RESULTS: Expression of PROK1 and PROKR1 was significantly higher in mid-gestation ovaries (17-20 weeks) than at earlier gestations (8-11 and 14-16 weeks). PROK2 significantly increased across the gestations examined. PROKR2 expression remained unchanged. PROK ligand and receptor proteins were predominantly localised to germ cells (including oocytes within primordial follicles) and endothelial cells, indicating these cell types to be the targets of PROK signalling in the human fetal ovary. PROK1 treatment of a germ cell line stably-expressing PROKR1 resulted in ERK phosphorylation, and elevated COX2 expression.CONCLUSIONS: Developmental changes in expression and regulation of COX2 and pERK by PROK1 suggest that PROK ligands may be novel regulators of germ cell development in the human fetal ovary, interacting within a network of growth and survival factors prior to primordial follicle formation.</p

    Violent and non-violent crimes against sex workers : the influence of the sex market on reporting practices in the United Kingdom

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    Previous research has shown that sex workers experience extremely high rates of victimization but are often reluctant to report their experiences to the police. This paper explores how the markets in which sex workers operate in the United Kingdom impact upon the violent and non-violent crimes they report to a national support organization and their willingness to report victimization to the police. We use a secondary quantitative data analysis of 2,056 crime reports submitted to the UK National Ugly Mugs (NUM) scheme between 2012 and 2016. The findings indicate that although violence is the most common crime type reported to NUM, sex workers operating in different markets report varying relative proportions of different types of victimization. We also argue that there is some variation in the level of willingness to share reports with the police across the different sex markets, even when the type crime, presence of violence, and other variables are taken into account. Our finding that street sex workers are most likely to report victimization directly to the police challenges previously held assumptions that criminalization is the key factor preventing sex workers from engaging with the police. Key words: sex work; violence; policing; reported victimizatio

    Soluble Abrasives for Waterjet Machining

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    This is an Accepted Manuscript of an article published by Taylor & Francis on 14th Aug 2014, available online: http://dx.doi.org/10.1080/10426914.2014.930949.© 2014 Taylor & Francis Group, LLC. The addition of hard abrasives to the jet in waterjet machining can improve machining rate, however, embedding of particles in machined surfaces is a limitation, which results in reduced fatigue life, and limits the application of well adhered subsequent coatings to the surface. In this study, softer soluble abrasives were investigated as a potential solution. Soluble abrasives yielded a higher material removal rate compared to plain waterjet, although were not as effective as traditional hard abrasives. Soluble abrasives reduced grit embedment on all four workpiece materials. A post-machining surface cleaning operation demonstrated that any remaining soluble abrasive could be removed

    Geometric quality assurance for 3D concrete printing and hybrid construction manufacturing using a standardised test part for benchmarking capability

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    The need for quality control and assurance in 3D Concrete Printing (3DCP) is widely recognised. Achieving geometric accuracy to a specified tolerance is a cornerstone of component-based production and assembly. Although published work within the field recognises such issues, these fall short of proposing systematic methods to evaluate, diagnose, improve, monitor and compare system performance. This work takes inspiration from the test geometry approach readily deployed in Additive Manufacturing and develops a full-scale test part to establish a reproducible benchmark for evaluating and assuring part geometric quality of 3DCP systems. The approach is used to evaluate the benefits of a new fabrication approach that combines subtractive milling on green cement mortar in combination with 3DCP. It was demonstrated to yield useful information for direct comparison of different processes and diagnosing problems for performance improvement. The test part and measurement approach offer the 3DCP community a means of cross-platform benchmarking of 3DCP system performance

    Digital technology and governance in transition: The case of the British Library

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    Comment on the organizational consequences of the new information and communications technologies (ICTs) is pervaded by a powerful imagery of disaggregation and a tendency for ?virtual? forms of production to be seen as synonymous with the ?end? of bureaucracy. This paper questions the underlying assumptions of the ?virtual organization?, highlighting the historically enduring, diversified character of the bureaucratic form. The paper then presents case study findings on the web-based access to information resources now being provided by the British Library (BL). The case study evidence produces two main findings. First, radically decentralised virtual forms of service delivery are heavily dependent on new forms of capacity-building and information aggregation. Second, digital technology is embedded in an inherently contested and contradictory context of institutional change. Current developments in the management and control of digital rights are consistent with the commodification of the public sphere. However, the evidence also suggests that scholarly access to information resources is being significantly influenced by the ?information society? objectives of the BL and other institutional players within the network of UK research libraries

    The Anti-social Behaviour, Crime and Policing Act 2014: implications for sex workers and their clients

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    © 2015 Taylor & Francis. The Anti-social Behaviour, Crime and Policing Act 2014 introduced new powers to deal with behaviour deemed to be ‘anti-social’. In this paper we consider how the new law could be used against sex workers and their clients and the impact this may have. Although the new powers were not intentionally designed to respond to prostitution, we suggest that they will be utilised to tackle it. We argue that the law will be used inconsistently in a way which will go directly against policy which seeks to ‘tackle demand’ and take a less punitive approach to dealing with sex workers. Despite a policy shift to see sex workers more as victims and less as offenders, we draw on existing evidence to demonstrate that the new anti-social behaviour order law will be utilised to exclude street sex workers from public spaces. We claim that a degree of ‘policy re-fraction’ will occur when the new laws are implemented by practitioners
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