Risk of injury and death from lightning in Northern Malawi     

Jonathan Salerno  Lameck Msalu  Tim Caro  Monique Borgerhoff Mulder 《Natural Hazards》2012,62(3):853-862

Rates of lightning mortality in communities on the western shore of Lake Malawi are higher than any other reported rate in the world: 419 strike victims per million people per annum and 84 deaths per million per annum. To document the background to this phenomenon, we conducted comprehensive household interviews with surviving victims and witnesses of every case of lightning strike in seven administrative areas around Nkhata Bay, Malawi. We find that the consequential lightning strikes are significantly more common in the rainy season and during the morning. Among those victims struck by lightning, there is an average ratio of approximately one death to four injuries, which is substantially higher than the commonly accepted ratio of 1:10. Children and adults are at equal risk of being struck. If struck, the probability of death is greater when the victim is outside in the open or outside under cover than indoors under a tin or thatched roof, but is unaffected by different kinds of footwear or whether it is raining. Reported explanations for strikes often center on witchcraft or other forms of social conflict. Our findings extend the study of consequential lightning strikes in the developing world and highlight cultural factors associated with this hazard. We end with recommendations for reducing the risk of lightning for rural populations.  相似文献   

Comparing the activity of aluminum in two B horizons developed from volcanic ash deposits in Japan, dominated by short-range ordered aluminosilicates and crystalline clay minerals, respectively     

Yasumi Yagasaki  Jan Mulder 《Geochimica et cosmochimica acta》2006,70(1):147-163

Mechanisms controlling the activity of free aluminum (Al) in Bw1 horizons of soils developed from volcanic ash deposits in Japan were investigated by means of acid-base titrations and kinetic studies. In a Bw1 horizon, with a high content of acid-oxalate extractable Al, soil solution reached equilibrium with short-range ordered aluminosilicates in the order of days. Relatively fast kinetics of the release and precipitation of Al and Si indicate a high reactivity of short-range ordered aluminosilicates in the soil. In the Bw1 horizon of an adjacent soil, with a high content of crystalline clay minerals like halloysite and interlayered vermiculite, solution remained well undersaturated with respect to short-range ordered aluminosilicates and aluminum hydroxide. Apparent equilibrium with respect to halloysite occurred after more than 30 days. This halloysite ( (25 °C)) has a solubility that is less than that reported in the literature ( (25°C)). Our findings suggest that different reactive aluminosilicates may control the activity of free Al in sub-surface horizons of volcanic ash soils with different mineralogy.  相似文献   

Concepts and science for coastal erosion management - An introduction to the Conscience framework     

Marcel Marchand  Agustin Sanchez-ArcillaMaria Ferreira  Jeremy GaultJosé A. Jiménez  Marina MarkovicJan Mulder  Leo van RijnAdrian St?nic?  Wojciech SuliszJames Sutherland 《Ocean & Coastal Management》2011,54(12):859-866

The main objective of the Conscience project was to develop and test concepts, guidelines and tools for the sustainable management of erosion along the European coastline, based on the best available scientific knowledge and on existing practical experience. Four concepts are potentially capable of providing the nexus between scientific knowledge and management: coastal resilience, coastal sediment cell, favourable sediment status and strategic sediment reservoir. The project has tested the use of these concepts and found that they are useful, provided that they are positioned and linked within a logical structure that we shall call the Conscience “Frame of Reference”, defined in time and space and supported through data and monitoring. Practical experience in six coastal sites in Europe has shown that the use of this Frame of Reference together with these concepts can make management objectives explicit and transparent. It can therefore support the design of an appropriate, resilience based coastal erosion management practice.  相似文献   

Characteristics of post-separation families in the Netherlands: shared residence versus resident mother arrangements     

Wilma Bakker  Clara H. Mulder 《GeoJournal》2013,78(5):851-866

Besides the traditional post-separation residential arrangement in which the children live with the mother and have regular contact with the father, new arrangements have emerged and become more widespread in which parents strive for a more equal division of tasks. We used an explanatory mixed methods research design to enhance insight into the life course characteristics of separated parents involved in shared residence arrangements. Survey data derived from the Netherlands Kinship Panel Study (NKPS) and Divorce in the Netherlands 1998 were supplemented with information from in-depth interviews with NKPS respondents. We found that shared residence parents seem to be a typical modern category of separated parents with a specific set of characteristics. The distance between the residences of the ex-partners plays a crucial role in maintaining a shared residence arrangement. Highly educated, dual-career ex-couples, and those with high incomes are also more likely to be involved in a shared residence arrangement. Shared residence arrangements were more likely when the woman had a new partner, but less likely when the man had a new partner. Our findings on gender differences are in line with the idea that involvement in non-traditional residential arrangements is a sign of increased paternal involvement, but decreased maternal involvement, compared with the traditional arrangements.  相似文献   

A comparison of continuous mass‐lumped finite elements with finite differences for 3‐D wave propagation     

Elena Zhebel  Sara Minisini  Alexey Kononov  Wim A. Mulder 《Geophysical Prospecting》2014,62(5):1111-1125

The finite‐difference method on rectangular meshes is widely used for time‐domain modelling of the wave equation. It is relatively easy to implement high‐order spatial discretization schemes and parallelization. Also, the method is computationally efficient. However, the use of finite elements on tetrahedral unstructured meshes is more accurate in complex geometries near sharp interfaces. We compared the standard eighth‐order finite‐difference method to fourth‐order continuous mass‐lumped finite elements in terms of accuracy and computational cost. The results show that, for simple models like a cube with constant density and velocity, the finite‐difference method outperforms the finite‐element method by at least an order of magnitude. Outside the application area of rectangular meshes, i.e., for a model with interior complexity and topography well described by tetrahedra, however, finite‐element methods are about two orders of magnitude faster than finite‐difference methods, for a given accuracy.  相似文献   

Isotope Approach to Assess Hydrologic Connections During Marcellus Shale Drilling     

Shikha Sharma  Michon L. Mulder  Andrea Sack  Karl Schroeder  Richard Hammack 《Ground water》2014,52(3):424-433

Water and gas samples were collected from (1) nine shallow groundwater aquifers overlying Marcellus Shale in north‐central West Virginia before active shale gas drilling, (2) wells producing gas from Upper Devonian sands and Middle Devonian Marcellus Shale in southwestern Pennsylvania, (3) coal‐mine water discharges in southwestern Pennsylvania, and (4) streams in southwestern Pennsylvania and north‐central West Virginia. Our preliminary results demonstrate that the oxygen and hydrogen isotope composition of water, carbon isotope composition of dissolved inorganic carbon, and carbon and hydrogen isotope compositions of methane in Upper Devonian sands and Marcellus Shale are very different compared with shallow groundwater aquifers, coal‐mine waters, and stream waters of the region. Therefore, spatiotemporal stable isotope monitoring of the different sources of water before, during, and after hydraulic fracturing can be used to identify migrations of fluids and gas from deep formations that are coincident with shale gas drilling.  相似文献   

THE EFFECT OF MEAN CENTERING ON PREDICTION IN MULTIVARIATE CALIBRATION     

MARY BETH SEASHOLTZ  BRUCE R.KOWALSKI 《地理学报(英文版)》1992,(2)

Traditionally,one form of preprocessing in multivariate calibration methods such as principal componentregression and partial least squares is mean centering the independent variables(responses)and thedependent variables(concentrations).However,upon examination of the statistical issue of errorpropagation in multivariate calibration,it was found that mean centering is not advised for some datastructures.In this paper it is shown that for response data which(i)vary linearly with concentration,(ii)have no baseline(when there is a component with a non-zero response that does not change inconcentration)and(iii)have no closure in the concentrations(for each sample the concentrations of allcomponents add to a constant,e.g.100%)it is better not to mean center the calibration data.That is,the prediction errors as evaluated by a root mean square error statistic will be smaller for a model madewith the raw data than a model made with mean-centered data.With simulated data relativeimprovements ranging from 1% to 13% were observed depending on the amount of error in thecalibration concentrations and responses.  相似文献   

Description of a drifter system used in experiments in the southern part of the North Sea     

Roelof Mulder  Marinus Wilhelmus Manuels 《Ocean Dynamics》1982,35(5):203-210

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"三七"高炮防雹对昭苏县气象站雹日数影响的统计分析   总被引：1，自引：0，他引：1  

瓦黑提  施文全  王红岩  邱辉  巴吾尔江 《沙漠与绿洲气象(新疆气象)》2003,26(1):25-26

根据昭苏县气象站1956－1973年（防雹前）和1974－1998年（防雹后）6－8月平均雹日数的变化，就“37”高炮防雹对下游地区雹日数的影响进行了统计分析。经计算，防雹后25年的平均雹日数比防雹前减少了3.8d，为了证明这一结果是人为影响还是自然变化，进行了序列检验和回归分析，表明，人工防雹使防区内雹日数显著减少，显著性水平分析达到0.001和0．01。  相似文献   

Controls on basalt terrace formation in the eastern Lesotho highlands     

Stefan Grab  Craig van Zyl  Nicholas Mulder 《Geomorphology》2005,67(3-4):473-485

The objective of this study is to ascertain the relative importance of lithological controls and geomorphological processes in the development of Drakensberg basalt terraces. Various hypotheses for terrace formation are considered, including geological controls, macroscale geomorphology, and climatic–geomorphological controls. The variations in strength and relative age differences for scarp surface exposures on two slopes of varying aspect are determined, so that a comparison can be made between various scarp outcrops and relative rates of weathering. Scarp outcrops were measured for their rock mass strength, rock surface roughness, and percentage lichen cover. The ethylene glycol test was performed on prepared rock samples to determine susceptibility to tensional breakup. A satellite image depicting the distribution of late-lying contemporary snow was used to assist in the construction of topo-climatic linkages with scarp terrace localities. Findings show that terraces are most common on southeast-facing aspects, and coincide with the major joint strike direction. Lithological factors are thus considered the primary control to such terrace development. It is suggested that a different set of geomorphological processes operates on various slope-altitudinal and slope-orientational positions at any given time.  相似文献