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971.
Jorge M. Mendes Patrícia Cortés de Zea Bermudez José Pereira K. F. Turkman M. J. P. Vasconcelos 《Environmental and Ecological Statistics》2010,17(1):1-28
In Portugal, due to the combination of climatological and ecological factors, large wildfires are a constant threat and due
to their economic impact, a big policy issue. In order to organize efficient fire fighting capacity and resource management,
correct quantification of the risk of large wildfires are needed. In this paper, we quantify the regional risk of large wildfire
sizes, by fitting a Generalized Pareto distribution to excesses over a suitably chosen high threshold. Spatio-temporal variations
are introduced into the model through model parameters with suitably chosen link functions. The inference on these models
are carried using Bayesian Hierarchical Models and Markov chain Monte Carlo methods. 相似文献
972.
Traditionally it has been assumed by ecologists that the dispersion of positions with respect to leks of female capercaillies
during the mating season is superior to the dispersion of positions of male capercaillies. However some recently published
articles suggest the idea that dispersion is not sex-biased, but both sexes show a similar dispersion. This article introduces
a mathematical model to approach the study of the above question by means of an indexed dispersion criterion. This model is
developed in detail thus deriving its main mathematical properties. On this basis, the model is applied to the analysis of
the motivating problem with real data of positions of leks and female and male capercaillies. The results derived by means
of the model put into doubt the traditional assumption of a superior dispersion of females supporting the new theories, that
is, both sexes show a similar dispersion. 相似文献
973.
Persistence models for mark-recapture 总被引:1,自引:0,他引:1
The stable of models available for analyzing mark-recapture data (Otis et al. Wild Momogr 66:135, 1978) includes those having
behavioral characteristics, time variation, heterogeneity, along with combinations of those characteristics. This paper proposes
use of a series of models based on the persistence model of Ramsey and Usner (Biometrics 59:331–339, 2003). We show that persistence
can be modeled in combination with behavior and with time variation. We apply the persistence model to situations in which
capture occasions are not equally-spaced in time. Two case studies illustrate the use of these extended persistence models. 相似文献
974.
Susan Barrett Peter Whittle Kerrie Mengersen Richard Stoklosa 《Environmental and Ecological Statistics》2010,17(4):503-519
We consider the problem of designing a surveillance system to detect a broad range of invasive species across a heterogeneous
sampling frame. We present a model to detect a range of invertebrate invasives whilst addressing the challenges of multiple
data sources, stratifying for differential risk, managing labour costs and providing sufficient power of detection. We determine
the number of detection devices required and their allocation across the landscape within limiting resource constraints. The
resulting plan will lead to reduced financial and ecological costs and an optimal surveillance system. 相似文献
975.
Climate change associated with sea level rise (SLR) is one of the major environmental concerns of today. This paper presents
an assessment of the impacts of sea level rise on the coastal zone of Kanyakumari District in Tamilnadu, India. Digital Elevation
Model (DEM) combined with overlay techniques in GIS are used in determining the inundation zones along the coastal region.
The analysis evaluated the impact on coastal fishing villages, landuse, tourist spots and sensitive areas under threat. The
vulnerability of the coastal areas in Kanyakumari to inundation was quantified, based on the projected sea level rise scenarios
of 0.5 and 1 m. Our findings reveal that approximately 13 km2 of the land area of Kanyakumari would be permanently inundated due to SLR. This would result in loss of land, alteration
of the coastal zone and affects coastal ecosystem. From the study, the mitigation measures (engineering measures) and Coastal
Zone Management practices that can be taken to protect human life and property from sea level rise are suggested. 相似文献
976.
Akshay A. Gowardhan Michael J. Brown Eric R. Pardyjak 《Environmental Fluid Mechanics》2010,10(3):311-328
This work describes and evaluates a pressure solver that has been incorporated into a fast response three-dimensional building-resolving
diagnostic wind modeling system. The solver computes the three-dimensional pressure field around buildings and on exterior
walls in terms of a coefficient of pressure by solving a simplified pressure Poisson equation (that neglects turbulence stresses
in the Navier-Stokes) for incompressible flow. The input to the solver is the three-dimensional mean wind field obtained from
a fast response empirical-diagnostic urban wind model. The present study is an evaluation of the pressure solver using wind-tunnel
data for flow normal to and at a 45° angle to an isolated cubical building. Results for the normal incident wind angle case
indicate that the model satisfactorily reproduces the general spatial patterns and the magnitude of the pressure difference
around much of the cube. Details of the flow field that are not satisfactorily predicted include the spatial distribution
of pressure on the roof and the lower half of the front side of the building and the magnitude along the sidewalls where pressures
are over predicted. The results for the 45° case show reasonable agreement between the model and experiments on the front
and the back walls, but over predict pressures on the leading edge of the rooftop. Regions with poor pressure predictions
appear to be a result of unsatisfactory mean wind modeling. 相似文献
977.
Mohammad Salehi Mohammad Mohammadi J. N. K. Rao Yves G. Berger 《Environmental and Ecological Statistics》2010,17(1):111-123
Adaptive cluster sampling (ACS) is an efficient sampling design for estimating parameters of rare and clustered populations.
It is widely used in ecological research. The modified Hansen-Hurwitz (HH) and Horvitz-Thompson (HT) estimators based on small
samples under ACS have often highly skewed distributions. In such situations, confidence intervals based on traditional normal
approximation can lead to unsatisfactory results, with poor coverage properties. Christman and Pontius (Biometrics 56:503–510,
2000) showed that bootstrap percentile methods are appropriate for constructing confidence intervals from the HH estimator.
But Perez and Pontius (J Stat Comput Simul 76:755–764, 2006) showed that bootstrap confidence intervals from the HT estimator
are even worse than the normal approximation confidence intervals. In this article, we consider two pseudo empirical likelihood
functions under the ACS design. One leads to the HH estimator and the other leads to a HT type estimator known as the Hájek
estimator. Based on these two empirical likelihood functions, we derive confidence intervals for the population mean. Using
a simulation study, we show that the confidence intervals obtained from the first EL function perform as good as the bootstrap
confidence intervals from the HH estimator but the confidence intervals obtained from the second EL function perform much
better than the bootstrap confidence intervals from the HT estimator, in terms of coverage rate. 相似文献
978.
Vittorio Barale 《Journal of Coastal Conservation》2010,14(4):317-326
The ecosystem approach requires that all elements of an ecosystem, and their mutual interactions, be taken into consideration
in any management effort. The selection of suitable geographical units, where this approach can be taken, requires the assessment
of ecological provinces, characterized by a coherent set of environmental traits. The marine side of coastal zones, where
the interaction between atmosphere, land and sea is not bounded by evident geographic markers, represents a critical factor
in this assessment. A coastal province can be defined by physical setting, but also by its bio-geo-chemical features, ideally
on the basis of synoptic remote sensing data, collected at space/time scales not accessible by other means. Classifications
based on indicators such as temperature, wind speed and chlorophyll-like pigments, demonstrate the identification of potential
ecological provinces in the Mediterranean Sea. The results suggest remote sensing as the ideal tool to set up the basis for
an ecosystem approach to the management of each province. 相似文献
979.
980.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the urban atmosphere and the atmospheric pollutants to be identified
as the most suspected carcinogens. In early measurements of urban PAH concentrations in Tehran area, the correlation between
concentrations of different species indicated that automobiles were the predominant source of emission of PAHs in this city.
From the diagnostic ratios, the results indicated that PAHs in the ambient air in Tehran originate primarily from diesel and
gasoline engines, but contribution of the related diesel emission is apparently higher, or dominant, at the sampling sites
and therefore considered as the major emission of PAHs in the ambient air. 相似文献