Modeling of space–time infectious disease spread under conditions of uncertainty     

José Miguel Angulo  Andreas Langousis  Ana Esther Madrid  George Christakos 《International journal of geographical information science》2013,27(10):1751-1772

A theoretical model for the spread of infectious diseases in a composite space–time domain is developed. The model has a general form that enables it to account for the basic mechanisms of disease distribution and to incorporate the considerable multisourced uncertainty (caused by physiographic features, disease variability, meteorological conditions, etc.). Starting from the general model formulation regarding the specification of transmission and recovery rates, as well as the population migration dynamics, several subsequent assumptions are introduced that simplify analytical tractability and practical implementation. In particular, linearization involving a deterministic functional representation for the average evolution of the fraction of susceptible individuals allows the formulation of an extended Kalman filter approach for estimation based on the time series observed at a finite set of locations. Different aspects of interest derived from the epidemic space–time model proposed, as well as the performance of the extended Kalman filter procedure, are illustrated through simulations.  相似文献   

Assessing progress in MRV capacity development: experience with a scorecard approach     

Till Neeff  Zoltán Somogyi  Corinna Schultheis  Esther Mertens  Joachim Rock  Johannes Brötz 《Climate Policy》2013,13(2):203-212

This article reports experiences gathered in 12 developing countries in Latin America and Africa with capacity development for national GHG inventory systems. The national systems and their ability to deliver on measurement, reporting and verification (MRV) requirements is assessed using a scorecard that covers the transparency, accuracy, completeness, consistency, and comparability of the GHG inventory as well as its institutional set-up and management aspects. The analysis shows that a quantitative assessment of GHG inventory systems with a scorecard is feasible and useful, and could commonly be used for tracking progress in MRV capacity development.

Policy relevance

A large number of capacity development initiatives are underway to advance national GHG inventory systems in developing countries, particularly in the land-use sector. These aim to promote the reliable MRV of GHG emissions and removals, which is expected to underpin developing countries’ contributions to global mitigation efforts, including through results-based payments. Although MRV is a cornerstone of climate change policy and despite widespread capacity gaps, there is little conclusive evidence about the effectiveness of such capacity development. This article relates the positive experience from one initiative, the Capacity Development for REDD+ project, which employed a novel, scorecard-based approach to results monitoring. Considerable progress is observed and provides reassurance regarding the soundness of development agencies’ significant investments in MRV. Disaggregating scores by countries and by underlying criteria also provides insights to prioritize further investments.  相似文献   

Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)     

Sofia Loureiro  Albert Reñé  Esther Garcés  Jordi Camp  Dolors Vaqué 《Journal of Sea Research》2011,65(4):401-413

The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007–October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment (Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) “spin-up” of upwelling (SU-Uw), and (3) “spin-down” and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local accumulation of harmful species. The associations found between harmful algal species and bacterioplankton and virioplankton call for detailed studies in order to evaluate species-specific interactions.  相似文献   

Finding a Way: Modeling Landscape Prerequisites for Roman and Early‐Medieval Routes in the Netherlands     

Rowin J. van Lanen  Menne C. Kosian  Bert J. Groenewoudt  Esther Jansma 《Geoarchaeology》2015,30(3):200-222

This study focuses on reconstructing landscape prerequisites for Roman and early‐medieval routes in the Netherlands. We applied spatial modeling to modern and paleogeographical landscape data in order to determine geographical obstacles for possible translocation in ca. A.D. 100 and 800 via land and water. Network‐friction values were calculated to produce a spatial model of possible movement corridors and to enable the integration of archaeological data. Results show that in geographically dynamic lowland regions such as the current Netherlands, landscape units such as water, peat, and levees must have had a high impact on route orientation. The lower parts of the western Netherlands were almost inaccessible by land, implying that its inhabitants largely must have depended on rivers and streams for transportation. In Dutch coastal and river areas, the landscape changed drastically between A.D. 100 and 800, the largest changes occurring along the coast.  相似文献   

Evaluation of the budget for silicic acid in Cascadia Basin deep water     

Tabitha A. Esther  Douglas E. Hammond  Susan L. Hautala  H. Paul Johnson  Richard J. Schwartz  Amelia N. Paukert 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(5):677-686

Between 2 and 3 km depth, North Pacific deep waters contain a plume of water with high silicic acid concentrations. The plume extends outward from Cascadia Basin (the Washington Margin), where waters can contain in excess of 200 μM off the coast of Oregon and Washington. To identify the source of the high Si concentrations in Cascadia Basin, we measured silicic acid and germanium concentrations in deep waters, and their fluxes from sediments using incubated cores. The mean flux of silicic acid into bottom waters is 0.81±0.05 mmol/m²-day, and the Ge/Si ratio of this flux is 0.7±0.1 μmol/mol. A box model, incorporating these results with hydrographic data, indicates that (1) no more than 5% of the silicic acid added to Basin deep waters can have a hydrothermal source (either hot or warm seeps), and (2) the total input of silicic acid to Basin deep waters is 0.06±0.02 Tmol/y. This input is nearly all from remineralized biogenic debris and should contribute about 0.5% of the 14 Tmol/y that are estimated to be necessary to maintain the North Pacific plume.  相似文献   

Women's participation in forest management: A cross-country analysis     

Eric A. Coleman  Esther Mwangi 《Global Environmental Change》2013,23(1):193-205

The role of women's participation in community forestry has recently been investigated in a number of theoretical and empirical papers. This paper takes an existing theoretical framework developed by Agarwal (2001) and applies it to examine two questions: (1) What determines women's participation in forestry institutions? and (2) What effect does women's participation have on institutional outcomes (such as levels of conflict and rule fairness)? To answer these questions data is used from two sources: (1) a detailed household survey conducted with 1.433 households in Bolivia, Kenya, Mexico, and Uganda and (2) a more aggregated dataset from forest associations investigated by the International Forestry Resources and Institutions (IFRI) program in 10 countries. The analyses suggest that women's participation is likely when institutions exist that are less exclusionary, when households have more education, and when there is small economic inequality in general and across genders in particular. A history of women's participation, especially when women are seated on forest councils or attain leadership positions, is highly correlated with less disruptive conflict.  相似文献   

Revised age estimate of the Mjáuvøtn tephra A on the Faroe Islands based on Bayesian modelling of 14C dates from two lake sequences     

Jesper Olsen  Esther Ruth Gudmundsdóttir  Svante Björck  Bent V. Odgaard  Jan Heinemeier 《第四纪科学杂志》2010,25(5):612-616

Tephra horizons are potentially perfect time markers for dating and cross‐correlation among diverse Holocene palaeoenvironmental records such as ice cores and marine and terrestrial sequences, but we need to trust their age. Here we present a new age estimate of the Holocene Mjáuvøtn tephra A using accelerator mass spectrometry ¹⁴C dates from two lakes on the Faroe Islands. With Bayesian age modelling it is dated to 6668–6533 cal. a BP (68.2% confidence interval) – significantly older and better constrained than the previous age. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Correlating Bedrock Folds to Higher Rates of Arsenic Detection in Groundwater,Southeast Wisconsin,USA     

Eric D. Stewart  Esther K. Stewart  Kenneth R. Bradbury  William Fitzpatrick 《Ground water》2021,59(6):829-838

Arsenic in private drinking water wells is a significant problem across much of eastern Wisconsin, USA. The release mechanism and stratigraphic distribution of sulfide and iron (hydr)oxide sources of arsenic in bedrock aquifers are well understood for northeastern Wisconsin. However, recent geologic mapping has identified numerous small bedrock folds to the south, and the impact of these geologic structures on local groundwater flow and well contamination has been little studied. This paper examines the hydrologic and structural effects of the Beaver Dam anticline, southeast Wisconsin, on arsenic in groundwater in the region. Multivariate logistic regression shows wells near the Beaver Dam anticline are statistically more likely to detect arsenic in groundwater compared to wells farther away. Structural and hydrologic changes related to folding are interpreted to be the cause. Core drilled near the fold axis is heavily fractured, and many fractures are filled with sulfides. Elevated hydraulic conductivity estimates are also recorded near the fold axis, which may reflect a higher concentration of vertical fractures. These structural and hydrologic changes may have led to systematic changes in the distribution and concentration of arsenic-bearing mineral hosts, resulting in the observed detection pattern. For areas with similar underlying geology, this approach may improve prediction of arsenic risk down to the local level.  相似文献   

Spatial p-q Resonant Orbits of the RTBP     

Esther Barrabés  Gerard Gómez 《Celestial Mechanics and Dynamical Astronomy》2002,84(4):387-407

The purpose of this paper is to extend the study of the so called p-q resonant orbits of the planar restricted three-body problem to the spatial case. The p-q resonant orbits are solutions of the restricted three-body problem which have consecutive close encounters with the smaller primary. If E, M and P denote the larger primary, the smaller one and the infinitesimal body, respectively, then p and q are the number of revolutions that P gives around M and M around E, respectively, between two consecutive close approaches. For fixed values of p and q and suitable initial conditions on a sphere of radius around the smaller primary, we will derive expressions for the final position and velocity on this sphere for the orbits under consideration.  相似文献   

Lower Miocene gypsum palaeokarst in the Madrid Basin (central Spain): dissolution diagenesis, morphological relics and karst end-products     

Juan P. Rodríguez-Aranda  José P. Calvo  M. Esther Sanz-Montero 《Sedimentology》2002,49(6):1385-1400

Abstract The Miocene sedimentary record of the Madrid Basin displays several examples of palaeokarstic surfaces sculpted within evaporite formations. One of these palaeokarstic surfaces represents the boundary between two main lithostratigraphic units, the Miocene Lower and Intermediate units of the Madrid Basin. The palaeokarst formed in lacustrine gypsum deposits of Aragonian age and corresponds to a surface palaeokarst (epikarst), further buried by terrigenous deposits of the overlying unit. Karst features are recognized up to 5·5 m beneath the gypsum surface. Exokarst and endokarst zones are distinguished by the spatial distribution of solution features, i.e. karren, dolines, pits, conduits and caves, and collapse breccias, sedimentary fills and alteration of the original gypsum across the karst profiles. The development of the gypsum palaeokarst began after drying out of a saline lake basin, as supported by recognition of root tubes, later converted to cylindrical and funnel‐shaped pits, at the top of the karstic profiles. The existence of a shallow water table along with low hydraulic gradients was the main factor controlling the karst evolution, and explains the limited depth reached by both exokarst and endokarst features. Synsedimentary fill of the karst system by roughly laminated to massive clay mudstone with subordinate carbonate and clastic gypsum reflects a punctuated sedimentation regime probably related to episodic heavy rainfalls typical of arid to semi‐arid climates. Duration of karstification is of the order of several thousands of years, which is consistent with previous statements that gypsum karstification can develop rapidly over geologically short time periods.  相似文献