The emerging chemical society and new political demands on improved ecological sustainability have put the urban water and sanitation system under pressure. It is recognised that the users need to partake in the problem solving, but to influence human practice we must understand it. A theoretical framework, founded on time-geography and cultural analysis, was developed and applied in a study on the interrelationship between changes in water and sanitation arrangements at the household level and residents’ routines. This article describes the theory cross-fertilisation and its prospect of application in studies of human environmental action. 相似文献
The aim of the study was to evaluate pattern of the aquatic macrophyte species distribution along the Danube fluvial corridor in Slovakia, and to identify the impact of environmental abiotic parameters on macrophyte species diversity. Field sampling was performed in the period 1999–2005 from the boat. Aquatic habitats were divided into 365 survey unit (SU). The survey of aquatic macrophytes and abiotic parameters followed the European standard approach EN 144184 2003. The plant mass estimate (PME – a semi-quantitative estimation of the amount of individual species in a SU, which takes into account three-dimensional development of plant stands) was estimated according to a five-point-scale in each SU; environmental pattern, were assessed over six abiotic parameters (river km, bank type, sediment type, flow velocity class, land-use type, and heavily man-modified water bodies). Altogether, four hydrologic connectivity types of aquatic habitats were distinguished: the Danube River, Open Arms, Separated Arms, and Seepage Water-bodies.
In total, 54 aquatic macrophytes were recorded for the whole data set of the Danube fluvial corridor. The PME data of true aquatic macrophytes and the length of SUs created a basis for numerical derivates, relative plant mass (RPM), mean mass indices (MMT, MMO) and the distribution ratio (d).
The results correspond with comparable studies on this topic: the highest macrophytes species diversity occurred in Separated Arms. On the contrary, macrophytes had the lowest richness in the Danube River main channel, although their diversity was slightly higher in heavily man-modified water bodies (such as the hydropower plant's reservoir and the abandoned main channel of the so-called Old Danube). Our results suggest that the lateral connectivity types of the river water bodies, primarily characterised by different hydrologic dynamics and human impact expressed as land-use types are responsible for the variability of aquatic macrophyte assemblages along the Danube corridor in Slovakia. 相似文献
In this paper we consider a Linear Regression Model with a design matrix that fits the periodic structure of a time series.
As a consequence, the residuals are very often autocorrelated. The main problem is that residual autocorrelation does not
necessarily entail error autocorrelation. To analyse the effects of selecting different formulations to accommodate the autocorrelation
in the residuals, we consider two seemingly different ways to deal with this problem: the Linear Regression Model with the
error terms following an Autoregressive Stationary Process and the Partial Adjustment Model. We study the equivalence between
the two formulations. We go over the problem of estimating the parameters and, especially, of making inferences in this framework.
After parameter estimation, we analyse the adequacy of the models. We demonstrate that the issue of selecting the most appropriate
model to capture the autocorrelation in the residuals is, in this context, a kind of an artefact since the main results concerning
the fitted values and forecasting features are the same. These modelling procedures are applied to the Portuguese coastal
upwelling data and we compare the estimated models. 相似文献
Methylmercury (MeHg) and inorganic mercury (Hginorg) were evaluated in the water of a Brazilian estuary, with two size classes of plankton and seven fish species of different feeding habits. Water partition coefficients (PCs) in microplankton were fourfold higher for MeHg than for Hginorg; and water PCs in mesoplankton were 26 times higher for MeHg than Hginorg. Difference between microplankton and mesoplankton MeHg bioaccumulation factor (BAF) was higher (0.60 log units) than Hginorg BAF (0.24 log units), indicating that trophic transfer of MeHg between planktonic organisms is more efficient than Hginorg transference. MeHg concentrations, proportion of mercury as MeHg and its biotransference factors (BTFs) in the microplankton, mesoplankton and fish increased with increasing trophic level while biotic concentrations of Hginorg and proportion of mercury as Hginorg decreased thus indicating that MeHg was indeed the biomagnified species of mercury. MeHg reflected the vertical trophic guilds distribution, due to the fact that the top predator fish presented the highest concentration (0.77 μg g−1 d.w.), followed by the less voracious species (0.43 μg g−1 d.w.); while planktivorous fish presented the lowest concentrations (0.044 μg g−1 d.w.). Hginorg did not present the same behavior. Results suggest that feeding habits and trophic guild are important parameters, influencing biotransference and biomagnification processes. 相似文献
Only a few chronological constraints on Lateglacial and Early Holocene glacier variability in the westernmost Alps have hitherto been obtained. In this paper, moraines of two palaeoglaciers in the southern Écrins massif were mapped. The chronology of the stabilization of selected moraines was established through the use of 10Be cosmic ray exposure (CRE) dating. The equilibrium line altitude (ELA) during moraine deposition was reconstructed assuming an accumulation area ratio (AAR) of 0.67. Ten pre‐Little Ice Age (LIA) ice‐marginal positions of the Rougnoux palaeoglacier were identified and seven of these have been dated. The 10Be CRE age of a boulder on the lowermost sampled moraine indicates that the landform may have been first formed during a period of stable glaciers at around 16.2±1.7 ka (kiloyears before AD 2017) or that the sampled boulder experienced pre‐exposure to secondary cosmic radiation. The moraine was re‐occupied or, alternatively, shaped somewhat before 12.2±0.6 ka when the ELA was lowered by 230 m relative to the LIA ELA. At least six periods of stable ice margins occurred thereafter when the ELA was 220–160 m lower than during the LIA. The innermost dated moraine stabilized at or before 10.9±0.7 ka. Three 10Be CRE ages from a moraine of the Prelles palaeoglacier indicate a period of stationary ice margins at or before 10.9±0.6 ka when the ELA was lowered by 160 m with respect to the end of the LIA. The presented 10Be CRE ages are in good agreement with those of moraines that have been attributed to the Egesen stadial. Assuming unchanged precipitation, summer temperature in the southern Écrins massif at ~12 ka must have been at least 2 °C lower relative to the LIA. 相似文献
Synoptic climatology relates the atmospheric circulation with the surface environment. The aim of this study is to examine the variability of the surface meteorological patterns, which are developing under different synoptic scale categories over a suburban area with complex topography. Multivariate Data Analysis techniques were performed to a data set with surface meteorological elements. Three principal components related to the thermodynamic status of the surface environment and the two components of the wind speed were found. The variability of the surface flows was related with atmospheric circulation categories by applying Correspondence Analysis. Similar surface thermodynamic fields develop under cyclonic categories, which are contrasted with the anti-cyclonic category. A strong, steady wind flow characterized by high shear values develops under the cyclonic Closed Low and the anticyclonic H–L categories, in contrast to the variable weak flow under the anticyclonic Open Anticyclone category. 相似文献
An attempt is made to explore the vertical structure of the surface explosive cyclones in the Mediterranean on a climatological basis during the cold period of the year in order to get a better insight in the interaction between the upper and lower levels responsible for the genesis and evolvement of the phenomenon. The vertical profile of the explosive cyclones was examined with the aid of the vertical tracing software of the University of Melbourne Cyclone Tracking Algorithm, using the 1?×?1° spatial resolution of ERA-40 reanalysis data. It was found that about 57?% of the track steps of surface explosive cyclones extend up to 500?hPa. The north-westward tilting of the surface cyclones with height during the stage of explosive cyclogenesis, with a mean distance of 350?km between mean sea and 500?hPa levels, confirms the importance of baroclinicity. About 45?% of the surface explosive cyclones reached their maximum depth before their 500?hPa counterparts, implying the role of surface processes. 相似文献
Lake Duluti is a small, topographically closed crater lake located on the flanks of Mt Meru, northern Tanzania. Analyses of diatoms in three short sediment cores and four modern samples from Lake Duluti were used to infer past environmental changes. 210Pb and 137Cs activity profiles combined with AMS 14C dates provide the chronological framework. Weak agreement between the 210Pb and 14C records, together with dating uncertainty, precludes construction of precise age models. The modern diatom flora, from plankton and three periphytic habitats, is dominated by Aulacoseira ambigua (Grunow) Simonsen, Gomphonema parvulum (Kützing) Grunow and Nitzschia amphibia Grunow. All three cores display similar stratigraphic succession, but the relative ratio of habitats represented by the diatoms varies substantially between cores. Diatoms indicate that the oldest part of the record is characterized by relatively low lake level and swampy vegetation. In the late nineteenth or early twentieth century there was a rapid lake level rise and the swamp turned into an open-water lake. High lake levels have prevailed since that time. 相似文献