1,218 research outputs found
Dependence on agriculture and ecosystem services for livelihood in Northeast India and Bhutan: vulnerability to climate change in the Tropical River Basins of the Upper Brahmaputra
No full textThe Upper Brahmaputra River Basin is prone to natural disasters and environmental stresses (floods, droughts and bank erosion, delayed rainfall, among others) creating an environment of uncertainty and setting the basin back in terms of socio-economic development. The climate change literature shows that agriculture and ecosystems and their services are highly climate sensitive, yet they are the main sources of livelihood that supports a large proportion of residents of the tributaries of the Brahmaputra River Basin. The continuous depletion of ecosystems and loss of agricultural outputs resulting from environmental stressors has a substantial impact on the socio-economic wellbeing of the basins residents, particularly the vulnerable rural poor. This paper uses spatially explicit data from Census, Household Surveys and Earth Observation to develop a transferable methodological approach which investigates the extent of dependence on agriculture and ecosystems as a source of livelihood in the contrasting sub-basins of the Brahmaputra River in the State of Assam, India and Bhutan, and the risk to these livelihood dependencies in these sub-basins due to potential environmental impacts of climate change. The results from this study constitute a case study in the development of a systematic and spatially explicit set of tools that inform and assist policy makers in the appropriate interventions to secure the livelihood benefits of sustainably managed agriculture in the face of environmental change
Flood inundation model updating using an ensemble Kalman filter and spatially distributed measurements
No full textThis paper examines critically the application to a site along the River Crouch,
Essex of a river-flow forecasting approach based on a one-dimensional hydraulic flow simulation
model updated using real-time data within an ensemble Kalman filtering framework.
Given a specified validation location and forecast period the objective of the forecasting
model was to estimate water level more accurately with updating than without. The method
used to estimate both model state and state uncertainty was evaluated in terms of its forecast
accuracy and representation of forecast uncertainty. The ensemble Kalman filter lead
to an increase in forecast accuracy of between 50% and 70% depending on location. The
hyperparameters of the filter could be calibrated to make estimates of forecast uncertainty
at a specific location, where the most data were available. However, the presence of systematic
errors in the simulation model and especially measurement data meant that uncertainty
estimates were inaccurate at other locations. Although, the major source of
uncertainty in this model came from the boundary condition, additional uncertainty within
the model domain was required, particularly between channel and floodplain. Changing the
temporal sampling rate and spatial density of samples had little effect on the accuracy of
forecasts at this site. However, uncertainty was under-estimated when the temporal sampling
rate was decreased, indicating that the relative uncertainties prescribed to the simulation
model and measurement model were inadequate
Is the fulfilment of objective wellbeing reflected in subjective wellbeing? A case study of vulnerable communities in Volta Delta, Ghana
No full textThere is growing interest in the measurement and conceptualisation of wellbeing due to its increasing importance within policy outcomes; however, the understanding of how different wellbeing outcomes associate within sustainability research is limited. This paper uses household survey data from the vulnerable Volta Delta, South Ghana, as a case study to illustrate the different philosophical approaches and measures of wellbeing, and the potential impact upon policy interventions. The frequent use of objective wellbeing measures, such as monetary poverty, within development policy is challenged as to whether it sufficiently reflects overall wellbeing. For example, objective monetary measures may not incorporate the intangible components of wellbeing, which can alternatively be captured within individuals’ self-evaluated, subjective wellbeing. This study first outlines the conceptual and methodological choices required when measuring wellbeing, before drawing on ideas of objective and subjective wellbeing to examine whether these concepts from different disciplines align or oppose one another. Contrasting theories within the literature justify this focus. By testing for associations between objective and subjective wellbeing outcomes, this study highlights how the methodological and conceptual choices made when measuring wellbeing can result in differing conclusions. Despite statistically significant associations being found amongst some wellbeing measures, results which show opposing outcomes highlight how subjective and objective wellbeing are not entirely interchangeable. Our study concludes there is a benefit to incorporating both objective and subjective measures in research and development targets across multiple scales to more-comprehensibly capture, and improve our understanding of, human wellbeing in vulnerable locations.<br/
Deriving Regression Lines Without Calculus
No full textThis article, C.W. Puritz of the Royal Grammar School - High Wycombe, describes a method to calculate the least squares line algebraically. First, the author uses a numeric example, which uses calculus, then describes a simpler algebraic method. This is a great lesson plan for those instructors attempting to teach this method with having students with prior knowledge of calculus. The author uses a step by step approach to help best describe both the technique and subsequent ways to best teach this method
Development and optimisation of a duplex real-time reverse transcription quantitative PCR assay targeting the VP7 and NS2 genes of African horse sickness virus
No full textNucleotide sequences of 52 South African isolates of African horse sickness virus (AHSV) collected during 2004–2005 and including viruses of all nine AHSV serotypes, were used to design and develop a duplex real-time reverse transcription quantitative PCR (RT-PCR) assay targeting the VP7 (S8) and NS2 (S9) genes of AHSV. The assay was optimized for detection of AHSV in fresh and frozen blood of naturally infected horses. Assay performance was enhanced using random hexamers rather than gene-specific primers for RT, and with denaturation of double-stranded RNA in the presence of random hexamers. The assay was efficient with a linear range of at least five orders of magnitude. The analytical sensitivity of the assay was 132 copies of the target genes (4125 copies per ml of blood), and the assay was at least 10-fold more sensitive than virus isolation on BHK-21 cells. The assay was also highly specific because it did not detect related orbiviruses, such as bluetongue and equine encephalosis viruses.ID: S0166093410000893; M3: Article; Accession Number: S0166093410000893; Author: M. Quan (a, b, ⁎); Author: C.W. Lourens (a, b); Author: N.J. MacLachlan (c); Author: I.A. Gardner (d); Author: A.J. Guthrie (a); Affiliation: Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Affiliation: Equine Viral Disease Laboratory, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Keyword: African horse sickness virus; Keyword: Real-time quantitative RT-PCR; Keyword: VP7 gene; Keyword: NS2 gene; Keyword: Duplex; Number of Pages: 8; Language: English
Nota, betreffende berekeningen omtrent rivierverbeteringen: opgemaakt door den ingenieur van den Rijkswaterstaat C.W. Lely
No full textHydraulische basis voor de normalisatiewerken van de grote rivieren. Berekingen van optimale breedte en diepte
Onderzoek naar signaalgeneratie met behulp van fasedraaiers ten behoeve van reflectie-compensatie in een F.M.-C.W. radarsysteem
No full textVoor onderzoek aan de troposfeer wordt gebruik gemaakt van een F.M.-C.W. radarsysteem. Een aspect van het radarsysteem waarnaar nog onderzoek gewenst is, is de onderdrukking van de overspraak van zender naar ontvanger, en van sterke reflecties aan nabije obstakels: deze signalen houden nl. het gevaar in van oversturing van de ontvanger. Dit aspect is met name van belang voor een mogelijk nog te realiseren F.M. -C.V. radarsysteem met één antenne…Applied SciencesElectrotechniekTelecommunicatie- en Verkeersbegeleidingssysteme
A Fourier-Based Valuation Method for Bermudan and Barrier Options under Heston’s Model
No full textWe develop an efficient Fourier-based numerical method for pricing Bermudan and discretely monitored barrier options under the Heston stochastic volatility model. The two-dimensional pricing problem is dealt with by a combination of a Fourier cosine series expansion, as in [F. Fang and C.W. Oosterlee, SIAM J. Sci. Comput., 31 (2008), pp. 826–848, F. Fang and C. W. Oosterlee, Numer. Math., 114 (2009), pp. 27–62], and high-order quadrature rules in the other dimension. Error analysis and experiments confirm a fast error convergence.Delft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
Nota betreffende het verband tusschen bodemhelling en kromtestraal bij rivieren, opgemaakt door den ingenieur van den Rijkswaterstaat dr. C.W. Lely
No full textRelatie kromtestraal en dwarshelling van rivieren, bevat data van de Nederlandse rivieren
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