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71.
Assessment of Spatiotemporal Varying Relationships Between Rainfall,Land Cover and Surface Water Area Using Geographically Weighted Regression 总被引:6,自引:0,他引:6
Stuart?BrownEmail author Vincent?L.?Versace Laurie?Laurenson Daniel?Ierodiaconou Jonathon?Fawcett Scott?Salzman 《Environmental Modeling and Assessment》2012,17(3):241-254
Traditional regression techniques such as ordinary least squares (OLS) are often unable to accurately model spatially varying
data and may ignore or hide local variations in model coefficients. A relatively new technique, geographically weighted regression
(GWR) has been shown to greatly improve model performance compared to OLS in terms of higher R
2 and lower corrected Akaike information criterion (AICC). GWR models have the potential to improve reliabilities of the identified relationships by reducing spatial autocorrelations
and by accounting for local variations and spatial non-stationarity between dependent and independent variables. In this study,
GWR was used to examine the relationship between land cover, rainfall and surface water habitat in 149 sub-catchments in a
predominately agricultural region covering 2.6 million ha in southeast Australia. The application of the GWR models revealed
that the relationships between land cover, rainfall and surface water habitat display significant spatial non-stationarity.
GWR showed improvements over analogous OLS models in terms of higher R
2 and lower AICC. The increased explanatory power of GWR was confirmed by the results of an approximate likelihood ratio test, which showed
statistically significant improvements over analogous OLS models. The models suggest that the amount of surface water area
in the landscape is related to anthropogenic drainage practices enhancing runoff to facilitate intensive agriculture and increased
plantation forestry. However, with some key variables not present in our analysis, the strength of this relationship could
not be qualified. GWR techniques have the potential to serve as a useful tool for environmental research and management across
a broad range of scales for the investigation of spatially varying relationships. 相似文献
72.
The technique of diffusion gradient in thin films (DGT) for assessing bioavailable metals has not been tested under field
conditions. We assessed the relationships of DGT- and cation exchange resin-membrane-measured concentrations of Cd, Cu, Pb,
and Zn with plant uptake of the metals under greenhouse and field conditions. In the greenhouse, the effective concentrations
of Cu, Pb, and Zn by DGT correlated significantly with uptake by sorghum (Sorghum bicolor), but cation exchange resin-membrane-measured concentrations of Cd, Pb, and Zn did not correlate with sorghum uptake. In
the field, the DGT-measured concentrations of Cd, Pb, and Zn were not linearly related to uptake Cd, Pb, and Zn by lettuce
(Lactuca sativa) except for Cu uptake (r = 0.87, p < 0.05). Similarly, it was only the resin-membrane-extractable Pb that correlated with Pb uptake by lettuce (r = 0.77; p < 0.05). However, fitting non-linear regression models improved the plant metal uptake predictions by DGT-measured bioavailable
Cd, Cu, Pb, and Zn under field conditions. In conclusion, the DGT technique was fairly predictive of bioavailability in the
greenhouse, but not in the field. 相似文献
73.
74.
75.
Sónia?Roxo José?António?de?AlmeidaEmail author Filipa?Vieira?Matias Herlander?Mata-Lima Sofia?Barbosa 《Environmental monitoring and assessment》2016,188(3):129
This paper proposes a multistep approach for creating a 3D stochastic model of total petroleum hydrocarbon (TPH) grade in potentially polluted soils of a deactivated oil storage site by using chemical analysis results as primary or hard data and classes of sensory perception variables as secondary or soft data. First, the statistical relationship between the sensory perception variables (e.g. colour, odour and oil–water reaction) and TPH grade is analysed, after which the sensory perception variable exhibiting the highest correlation is selected (oil–water reaction in this case study). The probabilities of cells belonging to classes of oil–water reaction are then estimated for the entire soil volume using indicator kriging. Next, local histograms of TPH grade for each grid cell are computed, combining the probabilities of belonging to a specific sensory perception indicator class and conditional to the simulated values of TPH grade. Finally, simulated images of TPH grade are generated by using the P-field simulation algorithm, utilising the local histograms of TPH grade for each grid cell. The set of simulated TPH values allows several calculations to be performed, such as average values, local uncertainties and the probability of the TPH grade of the soil exceeding a specific threshold value. 相似文献
76.
Combining field and laboratory work, this study investigated the reproductive cycle, aggregative behavior, spawning periodicity,
development and early growth of the sea star Henricia lisa living at bathyal depths off eastern Canada. Marked differences were found between individuals from ~1,300 and ~600 m deep.
The former had a male biased sex ratio and an aperiodic reproductive cycle, whereas the latter displayed an equal sex ratio
and a biannual breeding pattern. Furthermore, the maximum size was larger and female fecundity roughly five times higher in
shallower compared to deeper populations. In the tanks, aggregative behavior was recorded twice a year during the summer and
winter breeding periods. The onset of aggregations and spawning coincided with a temperature of 3–4°C. Males spawned first
and females typically responded inside 30–60 min. Between 12 and 20 eggs were retained to be brooded under the arched arms
of the female, whereas the remainder were broadcasted and developed without parental care. The fertilized eggs underwent a
first cleavage after 12 h, reached the brachiolaria stage in 1 month, became juveniles within 3–4 months and reached ~ 4 mm
in diameter after 14–17 months of growth. The embryos and juveniles developed at the same rate whether brooded or not, and
development of winter cohorts was typically slower due to lower prevailing temperatures. This study of H. lisa provides the first evidence of lecithotrophy in a seasonally breeding deep-sea echinoderm and of brooding in a deep-sea asteroid. 相似文献
77.
This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord,
Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night.
The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle,
to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further
understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer
along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence
potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical
migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination. 相似文献
78.
Pascal D. Leroy Ahmed Sabri Fran?ois J. Verheggen Fr��d��ric Francis Philippe Thonart Eric Haubruge 《Chemoecology》2011,21(3):113-122
In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects,
plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect
species, inducing particular behaviours, such as the localisation of a source of food, the orientation to an adequate oviposition
site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown
to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing
on the semiochemically mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as
important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted
by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect
evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many
interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest
management, advances in this field are discussed in the context of biological control against insect pests. 相似文献
79.
Elaine S. Carvalho Rubén J. Sánchez Maria I. B. Tavares álano C. Lam?nica 《Journal of Polymers and the Environment》2010,18(4):661-667
The chemical modification of Acrylamidomethyl Cellulose Acetate Propionate (AMCAP) was carried out by radical addition of
acrylic acid. The structural modification was confirmed with the aid of FTIR, MS and NMR techniques. Thermal properties of
hydrophilic cellulose derivative (AMCAP–H2O2) such as glass transition (Tg 153 °C) and thermal stability (372.7 °C) were determined by DSC and TGA techniques, respectively. These thermal properties
confirmed the introduction of carboxylic groups into AMCAP structure, which causes an impact in their properties. The AMCAP–H2O2 shows minor contact angle compared to AMCAP, giving a more hydrophilic characteristic, due to acrylic acid addition into
the side chains of AMCAP polymer. 相似文献
80.
The concentrations of heavy metals and metals (Zn, Pb, Bi, Cd, Ni, Co, Fe, Mn, Mg, Cu, Cr, Ca, Sr, Na, Li, K) were measured in muscle of five species Cyprinus carpio (from I??kl? dam), Scardinius erythrophthalmus (from I??kl? dam), Tinca tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), Carassius carassius (from Karaca?ren dam) caught from I??kl? and Karaca?ren. The highest metal was Na (466.95 μg/g) in C. carassius, while the lowest levels were Fe (0.37 μg/g) and Cu (0.37 μg/g) in C. carpio from I??kl? dam. The mean concentrations μg/g d.w. some of heavy metals in muscle of C. carpio (from I??kl? dam), S. erythrophthalmus (from I??kl? dam), T. tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), C. carassius (from Karaca?ren dam) were as follows: Cd 2.00-2.10-1.95-2.06-2.27, Zn 4.36-2.64-13.13-13.33-24.47, Pb 1.65-1.24-1.90-2.37-2.41, Co 2.46-2.37-2.48-2.58-2.80, Mg 138.51-154.35-218.59-204.58-202.16, Fe 0.37-2.62-3.17-3.01-12.33, respectively. 相似文献