Regional variability in relationships between climate and dengue/DHF in Indonesia   总被引：2，自引：0，他引：2  

Paula Arcari  Nigel Tapper  Sharron Pfueller 《Singapore journal of tropical geography》2007,28(3):251-272

Since 1970, the worldwide distribution, frequency and intensity of epidemics of dengue and dengue haemorrhagic fever (DHF) have increased dramatically. In Indonesia, as elsewhere, the geographic distribution and behaviour of the two main vectors – Aedes aegypti and Aedes albopictus – and the consequent transmission dynamics of the disease are strongly influenced by climate. Monthly incidence data were examined in relation to monthly data for temperature, rainfall, rainfall anomalies, humidity and the Southern Oscillation Index for 1992–2001. Focusing on eight provinces, significant Pearson correlations were observed between dengue/DHF incidence and at least one climate variable ( r  = ±0.2 to ±0.43; P  < 0.05). Multiple regression analyses showed that 12.9–24.5 per cent of variance in incidence was explained by two or three climate variables in each province ( P  < 0.1–0.01). Rainfall appears to be the principal climatic agent affecting the geographic distribution and temporal pattern of incidence while temperature appears to play a critical role in outbreak intensity. Wide regional and temporal variations in the strength and nature of the observed associations led to the identification of three groups of provinces where increases in dengue/DHF incidence were variously associated with increased rainfall, decreased rainfall and/or high susceptibility to climate variability. Although climatic factors play an important role in explaining the timing and intensity of dengue/DHF outbreaks, a wide range of other factors specific to local environments also appear to be involved – information that may assist in the prediction and mitigation of regional dengue/DHF outbreaks.  相似文献   

Effectiveness of simple approaches in mitigating residual deformations in buildings     

Didier Pettinga  Constantin Christopoulos  Stefano Pampanin  Nigel Priestley 《地震工程与结构动力学》2007,36(12):1763-1783

Developments in performance‐based seismic design and assessment approaches have emphasized the importance of considering residual deformations. Recent investigations have also led to a proposed direct displacement‐based design (DDBD) approach which includes an explicit consideration of the expected residual deformations as an integral part of the design process. Having estimated the expected residual deformations in a structure, engineers are faced with the problem of reducing them to meet the targeted performance levels under pre‐defined seismic hazard levels. Previous studies have identified the post‐yield stiffness as a primary factor influencing the magnitude of residual deformations in single degree of freedom and multiple degree of freedom structures. In this paper, a series of simple approaches to increase the post‐yield stiffness of traditional framed and braced systems for the purpose of reducing residual deformations are investigated. These methods do not utilize recentring post‐tensioned technology. This contribution addresses the feasibility of altering the lateral post‐yield stiffness of structural systems by: (i) using different reinforcement materials with beneficial features in their stress–strain behaviour; (ii) re‐designing the section geometry and properties of primary seismic‐resisting elements; and (iii) introducing a secondary elastic frame to act in parallel with the primary system. The efficiency of each of these techniques is investigated through monotonic and cyclic moment‐curvature and non‐linear time‐history analyses. Of these approaches the design and introduction of an elastic secondary system was found to be most effective and consistent in reducing residual deformations. A simplified design approach for achieving the desired increase of a system's post‐yield stiffness is also presented. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Adapting to climate change: Public water supply in England and Wales   总被引：1，自引：0，他引：1  

Nigel W. Arnell  E. Kate Delaney 《Climatic change》2006,78(2-4):227-255

This paper describes an assessment of the ways in which water supply companies in England and Wales are adapting to climate change, evaluated in the context of a model of the adaptation process. The four components of the model are (i) awareness of and concern about the potential impacts of climate change, (ii) adaptation strategy, (iii) the concept of an adaptation space from which options are selected, and (iv) the notion that three groups of factors influence awareness, strategy and option selection: susceptibility to change, internal characteristics of the organisation, and regulatory and market context.Public water supply in England and Wales is provided by private sector companies, subject to environmental and economic regulation. Hydrological simulations suggest that climate change has the potential to reduce the reliability of supply sources over the next few decades. The industry in December 2004 completed a review of investment requirements over the next five years.Awareness of climate change is high in the water industry, but by developing assessment procedures and incorporating them into the investment review the regulators forced companies to consider explicitly the potential impacts of climate change in a consistent and rigorous manner. These analyses combined climate change with other pressures on water resources, and in practice companies did not attribute specific investment decisions or proposals to climate change or indeed any other individual drivers. The broad strategy adopted by all water supply companies – to maintain standards of service – is determined by regulatory controls and market considerations, but the degree of concern about the impacts of climate change and precise adaptation options necessary to address supply-demand imbalances varied between water supply companies, reflecting local geographic conditions. The water supply companies and regulators have different perspectives on the relative merits of supply-side and demand-side measures, reflecting different organisational priorities.The 2004 investment review determined that no specific actions were necessary to deal with future climate change, but that measures set in place – in terms of methodologies and investment in investigations into specific resource developments – provided a sound foundation for more specific actions in the next investment review in five years time. The paper concludes by summarising the factors assisting and constraining adaptation over the next few decades.  相似文献   

Shark interactions in pelagic longline fisheries   总被引：1，自引：0，他引：1  

Eric Gilman  Shelley Clarke  Nigel Brothers  Joanna Alfaro-Shigueto  John Mandelman  Jeff Mangel  Samantha Petersen  Susanna Piovano  Nicola Thomson  Paul Dalzell  Miguel Donoso  Meidad Goren  Tim Werner 《Marine Policy》2008

Substantial ecological, economic and social problems result from shark interactions in pelagic longline fisheries. Improved understanding of industry attitudes and practices towards shark interactions assists with managing these problems. Information on fisher knowledge and new strategies for shark avoidance may benefit sharks and fishers. A study of 12 pelagic longline fisheries from eight countries shows that incentives to avoid sharks vary along a continuum, based on whether sharks represent an economic disadvantage or advantage. Shark avoidance practices are limited, including avoiding certain areas, moving when shark interaction rates are high, using fish instead of squid for bait and deeper setting. Some conventionally employed fishing gear and methods used to target non-shark species contribute to shark avoidance. Shark repellents hold promise; more research and development is needed. Development of specifically designed equipment to discard sharks could improve shark post release survival prospects, reduce gear loss and improve crew safety. With expanding exploitation of sharks for fins and meat, improved data collection, monitoring and precautionary shark management measures are needed to ensure that shark fishing mortality levels are sustainable.  相似文献   

A structural and geophysical approach to the study of fractured aquifers in the Scansano-Magliano in Toscana Ridge, southern Tuscany, Italy   总被引：1，自引：0，他引：1  

Roberto Francese  Francesco Mazzarini  Andrea Bistacchi  Gianfranco Morelli  Giorgio Pasquarè  Nicola Praticelli  Henry Robain  Nigel Wardell  Annalisa Zaja 《Hydrogeology Journal》2009,17(5):1233-1246

Fresh water availability has recently become a serious concern in the Italian Apennines, as various activities rely on a predictable supply. Along the ridge between Scansano and Magliano in Toscana, in southern Tuscany, the situation is further complicated by contamination of the nearby alluvial aquifers. Aquifers locally consist of thin fractured reservoirs, generally within low-permeability formations, and it can be difficult to plan the exploitation of resources based on conventional techniques. An integrated study based on geological data investigated the link between tectonics and groundwater circulation, to better define the hydrological model. After the regional identification of fault and fracture patterns, a major structure was investigated in detail to accurately map its spatial position and to understand the geometry and properties of the associated aquifer and assess its exploitation potential. The subsurface around the fault zone was clearly imaged using ground probing radar, two-dimensional and three-dimensional resistivity tomography, and three-dimensional shallow seismic surveys. The vertical and horizontal contacts between the different geological units of the Ligurian and Tuscan series were resolved with a high degree of spatial accuracy. Three-dimensional high-resolution geophysical imaging proved to be a very effective means of characterising small-scale fractured reservoirs.  相似文献   

Strata and Time: Probing the Gaps in our Understanding,edited by D.G. Smith,R.J. Bailey,P.M. Burgess and A.J. Fraser. Geological Society,London, Special Publication, 404, 2015. No. of pages: vii+325. Price: UK £120.00. ISBN 978-1-86239-655-5 (hardback).     

Nigel Ainsworth 《Geological Journal》2016,51(6):966-966

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Archean to Recent aeolian sand systems and their sedimentary record: Current understanding and future prospects     

Juan Pedro Rodríguez‐López  Lars B. Clemmensen  Nick Lancaster  Nigel P. Mountney  Gonzalo D. Veiga 《Sedimentology》2014,61(6):1487-1534

The sedimentary record of aeolian sand systems extends from the Archean to the Quaternary, yet current understanding of aeolian sedimentary processes and product remains limited. Most preserved aeolian successions represent inland sand‐sea or dunefield (erg) deposits, whereas coastal systems are primarily known from the Cenozoic. The complexity of aeolian sedimentary processes and facies variability are under‐represented and excessively simplified in current facies models, which are not sufficiently refined to reliably account for the complexity inherent in bedform morphology and migratory behaviour, and therefore cannot be used to consistently account for and predict the nature of the preserved sedimentary record in terms of formative processes. Archean and Neoproterozoic aeolian successions remain poorly constrained. Palaeozoic ergs developed and accumulated in relation to the palaeogeographical location of land masses and desert belts. During the Triassic, widespread desert conditions prevailed across much of Europe. During the Jurassic, extensive ergs developed in North America and gave rise to anomalously thick aeolian successions. Cretaceous aeolian successions are widespread in South America, Africa, Asia, and locally in Europe (Spain) and the USA. Several Eocene to Pliocene successions represent the direct precursors to the present‐day systems. Quaternary systems include major sand seas (ergs) in low‐lattitude and mid‐latitude arid regions, Pleistocene carbonate and Holocene–Modern siliciclastic coastal systems. The sedimentary record of most modern aeolian systems remains largely unknown. The majority of palaeoenvironmental reconstructions of aeolian systems envisage transverse dunes, whereas successions representing linear and star dunes remain under‐recognized. Research questions that remain to be answered include: (i) what factors control the preservation potential of different types of aeolian bedforms and what are the characteristics of the deposits of different bedform types that can be used for effective reconstruction of original bedform morphology; (ii) what specific set of controlling conditions allow for sustained bedform climb versus episodic sequence accumulation and preservation; (iii) can sophisticated four‐dimensional models be developed for complex patterns of spatial and temporal transition between different mechanisms of accumulation and preservation; and (iv) is it reasonable to assume that the deposits of preserved aeolian successions necessarily represent an unbiased record of the conditions that prevailed during episodes of Earth history when large‐scale aeolian systems were active, or has the evidence to support the existence of other major desert basins been lost for many periods throughout Earth history?  相似文献   

A non-main-sequence secondary in SY Cancri     

Robert Connon Smith  Otto Mehes  Dave Vande Putte  Nigel A. Hawkins 《Monthly notices of the Royal Astronomical Society》2005,360(1):364-374

Simultaneous spectroscopic and photometric observations of the Z Cam type dwarf nova SY Cancri were used to obtain absolute flux calibrations. A comparison of the photometric calibration with a wide-slit spectrophotometric calibration showed that either method is equally satisfactory. A radial velocity study of the secondary star, made using the far-red Na  i doublet, yielded a semi-amplitude of   K ₂= 127 ± 23 km s⁻¹  . Taking the published value of  86 ± 9 km s⁻¹  for K ₁ gives a mass ratio of   q = M ₂/ M ₁= 0.68 ± 0.14  ; this is very different from the value of  1.13 ± 0.35  quoted in the literature. Using the new lower mass ratio, and constraining the mass of the white dwarf to be within reasonable limits, then leads to a mass for the secondary star that is substantially less than would be expected for its orbital period if it satisfied a main-sequence mass–radius relationship. We find a spectral type of M0 that is consistent with that expected for a main-sequence star of the low mass we have found. However, in order to fill its Roche lobe, the secondary must be significantly larger than a main-sequence star of that mass and spectral type. The secondary is definitely not a normal main-sequence star.  相似文献   

A proposal for a new scenario framework to support research and assessment in different climate research communities   总被引：1，自引：0，他引：1  

Detlef P. van Vuuren  Keywan Riahi  Richard Moss  Jae Edmonds  Allison Thomson  Nebojsa Nakicenovic  Tom Kram  Frans Berkhout  Rob Swart  Anthony Janetos  Steven K. Rose  Nigel Arnell 《Global Environmental Change》2012,22(1):21-35

In this paper, we propose a scenario framework that could provide a scenario “thread” through the different climate research communities (climate change – vulnerability, impact, and adaptation - and mitigation) in order to support assessment of mitigation and adaptation strategies and climate impacts. The scenario framework is organized around a matrix with two main axes: radiative forcing levels and socio-economic conditions. The radiative forcing levels (and the associated climate signal) are described by the new Representative Concentration Pathways. The second axis, socio-economic developments comprises elements that affect the capacity for mitigation and adaptation, as well as the exposure to climate impacts. The proposed scenarios derived from this framework are limited in number, allow for comparison across various mitigation and adaptation levels, address a range of vulnerability characteristics, provide information across climate forcing and vulnerability states and span a full century time scale. Assessments based on the proposed scenario framework would strengthen cooperation between integrated-assessment modelers, climate modelers and vulnerability, impact and adaptation researchers, and most importantly, facilitate the development of more consistent and comparable research within and across these research communities.  相似文献   

Aerosols and their influence on radiation partitioning and savanna productivity in northern Australia     

Kasturi Devi Kanniah  Jason Beringer  Nigel J. Tapper  Chuck N. Long 《Theoretical and Applied Climatology》2010,100(3-4):423-438

Aerosols have been shown to affect the quantity and quality of solar radiation on the Earth’s surface. Savanna regions are subject to frequent burning and release of aerosols that may impact on radiation components and possibly vegetation productivity in this region. Therefore, in this study, we have analyzed the optical properties of aerosols (aerosol optical depth (AOD) and Angstrom coefficient) from the Atmospheric Radiation Measurement site in Darwin for the periods from April 2002 to June 2005 as measured by a multifilter rotating shadowband radiometer. The influence of aerosols and their effect on surface shortwave incoming solar radiation and savanna productivity were examined for the dry season using sky radiation collection of radiometers and eddy covariance measurements from the Howard Springs flux site. Results indicated that aerosol concentrations in the region were relatively low compared to other savanna regions with the maximum monthly average AOD over the period being the greatest in October (0.29?±?0.003 standard error at 500 nm). The highest monthly average Angstrom exponent was also found in October (1.38?±?0.008). The relatively low aerosol concentration in this region can be attributed to the mixture of smoke aerosols with humidity haze and local circulations. Over a range of AODs from 0.1 to 0.4, we found a modest increase in the fraction of diffuse radiation to total radiation from 11% to 21%. This small increase in diffuse fraction did not affect the carbon flux significantly. However, because the current range of AOD in the region is relatively low, the region could be sensitive to increases in aerosols and diffuse fraction in the future.  相似文献