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51.
David W. Watkins Jr. Márcia M. G. Alcoforado de Moraes Heidi Asbjornsen Alex S. Mayer Julian Licata Jose Gutierrez Lopez Thomas G. Pypker Vivianna Gamez Molina Guilherme Fernandes Marques Ana Cristina Guimaraes Carneiro Hector M. Nuñez Hayri Önal Bruna da Nobrega Germano 《Environmental management》2015,56(6):1295-1314
52.
Using system dynamics to model water-reallocation 总被引:2,自引:0,他引:2
Improving the efficiency of water allocation has long been recognised as a key problem for the water resources management
decision-makers. However, assessing the efficacy of management decision is difficult due to the complexity and interconnectivity
of water resource systems. For this reason, it is vital that robust modelling approaches are employed to deal with the feedback
loops inherent in the water resource systems. Whilst many studies have applied modelling to various aspects of water resource
management, little attention has been given to innovations in modelling approaches to deal with the modelling challenges associated
with improving decision-making.
The aim of this study is to apply a System Dynamics modelling approach to improve the efficiency of water allocation incorporating
a myriad of irrigation system constraints. The system dynamic approach allows the different system components to be organised
as a collection of discrete objects that incorporate data, structure and function to generate complex system behaviour. Through
the application of a system dynamic approach, a robust model (named the Economical Reallocating Water Model (ERWM)) was developed
which was used to examine the options of re-allocating water resources that minimize the water cost all over an irrigated
agricultural area. The EWRM incorporated a wide range of complexities likely to be encountered in water resource management:
surface and ground water sources, water trading between sources, system constraint such as maximum ground water pumping, rates,
maximum possible trading volumes and differential water resource prices. Two hypothetical systems have been presented here
as an example. The results show that the System Dynamics approach has a significant advantages in estimating and assessing
the outcomes of alternative water management strategies through time and space. 相似文献
53.
54.
Because of the significant impacts on both human interests and bird conservation, it is imperative to identify patterns and anticipate drivers of human–bird conflicts (HBCs) worldwide. Through a global systematic review, following the PRISMA 2020 guidelines, we analyzed the socioeconomic factors and bird ecological traits driving the degree of knowledge and extent of HBCs. We included 166 articles published from 1971 to 2020 in our analyses through which we built a profile of the socioeconomic conditions of 52 countries with reported conflicts and the ecological traits of the 161 bird species involved in HBCs. Although HBC expanded worldwide, it had the greatest impact in less-developed countries (estimate 0. 66 [SE 0.13], p< 0.05), where agriculture is critical for rural livelihoods. Species with a relatively greater conflict extent had a relatively broader diet (estimate 0.80 [SE 0.22], p<0.05) and an increasing population trend (estimate 0.58 [SE 0.15], p<0.05) and affected human interests, such as agriculture and livestock raising. In countries with greater biodiversity, HBCs caused greater socioeconomic impacts than in more developed countries. Our results highlight the importance of understanding and addressing HBCs from multiple perspectives (ecological, sociocultural, and political) to effectively protect both biodiversity and local livelihoods. 相似文献
55.
The city of Salamanca in central Mexico is surrounded by heavy industry, i.e., a refinery, a thermoelectric plant and chemical industries. Variable concentrations of vanadium (V) have been reported in the groundwater, and their presence has been related to particulates so this hypothesis was tested by sampling soil in the urban area and the surrounding uncontaminated country site. The 0-10-cm soil layer in the industrial and rural area was analyzed for V and other metal trace elements found in hydrocarbons, i.e., chromium (Cr), lead (Pb), zinc (Zn), and nickel (Ni). The concentrations of V were higher in the urban rather than in the rural soil, reaching values of >600 mg kg(-1) in the urban soils. In the rural area, V in the soil was related to regional geology, i.e., volcanic rocks such as basalts and rhyolites but not in the urban area where it was related to particulate distribution mostly emitted from the industries burning fuel oil number 6. 相似文献
56.
This study assessed the changes in extent of fringing mangrove located in Punta Mala Bay, Panama in relation to coastal development over a period of two decades. Punta Mala Bay was chosen for this study, due to its social importance and its biological significance, as it is one of the few mangrove areas left around Panama City. Fieldwork confirmed the importance of Laguncularia racemosa in the bay, which formed nearly monospecific stands with a large number of seedlings indicating that the forest was rejuvenating. The mangrove was mapped from 1980 to 2002 using digitised aerial photographs and a GIS was used to determine the location and rates of mangrove growth and loss before and after the construction of a road and water treatment works in 1998. The land use maps were produced with an overall accuracy of 83.8%. The user's accuracy of the maps for L. racemosa dominated stands was 89.7%, although the producer's accuracy was lower due to the omission of seedlings on intertidal areas. It was found that the mangrove was spatially dynamic and had grown substantially in the bay at a rate ranging from 6 to 215% per year until the construction commenced. Between 1997 and 2002 there were 100% loss of mangrove in some areas due to the coastal development. The resilience of the dominant species L. racemosa at this locality was shown by the continued growth of two mangrove zones during the construction period 1997-2002, with one zone increasing in area by 61%. The pioneering ability of L. racemosa after disturbance was demonstrated by the development of two new mangrove zones of 498 and 1254 m2 on bare intertidal areas after construction finished. Future mapping and fieldwork could provide information on the development of mangrove communities and their response to reoccurring human impacts. 相似文献
57.
Wendy Bailey Gary R. Freidenberg Hector E. James John R. Hesselink Kenneth Lee Jones MD 《黑龙江环境通报》1990,10(10):623-629
We report an infant with a craniopharyngioma which was detected in utero. Maternal uterine ultrasonography, done at 27 weeks because of polyhydramnios, revealed a 4 cm midline mass near the base of the fetal skull. At 31 weeks, magnetic resonance imaging of the maternal abdomen confirmed the presence of a mass in the region of the third ventricle and revealed hydrocephalus. Two days post-partum a computed tomography (CT)-guided needle biopsy of the mass was performed and recovered tissue which was histologically consistent with a craniopharyngioma. The infant' s postnatal period was complicated by seizures, which were treated with phenobarbital, and by progressive hydrocephalus, necessitating placement of a ventriculo-peritoneal shunt. He also received therapy for central hypothyroidism and diabetes insipidus. The infant' s parents refused permission for attempted resection of the tumour and he died at 8 weeks of age. This represents the second reported case of an antenatally detected craniopharyngioma. Four other cases of different intracranial tumours have been detected in utero using ultrasound, with no reported survivors past 3 days of age. There is a uniformly poor prognosis of such infants, but earlier diagnosis and intervention may change this result. 相似文献
58.
The fate and effect of nanomaterials in the environment is of paramount importance towards the technological application of the materials. This work shows the ecotoxicological potential of polyaniline (PANI) nanofibers in the larvae Rhinella arenarum by means of AMPHITOX test. Acute toxicity of PANI nanofibers towards embryos of the common South American toad R. arenarum (Anura: bufonidae) was evaluated in the premetamorphosis (stage 25) larvae. The exposure of R. arenarum larvae to at dose of 150, 250 and 400 mg L−1 resulted in 100% viability within 96 h exposure. The embryos at 2-4 blastomers stage (early life stage teratogenic test) revealed that embryos were not killed and no teratogenic effects were observed when embryos were incubated with PANI nanofibers (150 and 250 mg L−1), while only a growth retardation of embryos was induced at levels of 250 mg PANI nanofibers L−1. On the other hand, at 400 mg L−1 concentration, a reduction in the body length of larvae and tail malformation was observed. This results suggest that a concentration-dependent toxicity is operative, typified by phenotypes that had abnormal body axes. The presence of PANI nanofibers in gut contents and its excretion by larval stages of R. arenarum was confirmed by UV-visible spectroscopy. 相似文献
59.
Rubio MA Lissi E Jorquera H Salinas E Castro J Cádiz M 《Environmental monitoring and assessment》2008,140(1-3):161-173
Carbon monoxide concentrations were measured at ground level (1 m) near heavy traffic streets in downtown Santiago de Chile
in periods of low (November and December), intermediate (April) and high (May) ambient concentrations. Also, measurements
were carried out at several heights (from 1 to 127 m) in Santiago’s main street during winter time. Measurements carried out
at ground level show maximum values during the morning rush hour, with values considerably higher than those reported by the
urban air quality network, particularly in summer time. However, the measured values are below air quality standards. Vertical
CO profiles were measured in a tower located in the center of downtown. Below 40 m (average altitude of neighboring buildings),
the profiles do not show a consistent vertical gradient, with CO concentrations increasing or decreasing with height, regardless
of atmospheric stability. In this low altitude range, the observed vertical profiles are poorly predicted by a street canyon
model, and the measured concentrations can not be described by a simple exponential decay. At higher altitudes (40 and 127 m)
a negative gradient in CO concentrations is observed, both for stable and unstable atmospheric conditions. The values of CO
measured at 127 m are relatively well described by an Eulerian dispersion model running with current CO emission inventories
for Santiago, although this model tends to predict stepper CO gradients than the observed ones. 相似文献
60.
José Luis Iriarte Silvio Pantoja Humberto E. González Gabriela Silva Hector Paves Pamela Labbé Lorena Rebolledo Murat Van Ardelan V. Häussermann 《Environmental monitoring and assessment》2013,185(6):5055-5070
Anthropogenic (aquaculture) changes in environment nutrient concentrations may affect phytoplankton (biomass and taxa composition) in marine coastal waters off the Chilean Patagonia. The effects of adding nitrate (NO3 ?) to natural phytoplankton assemblages were evaluated considering biomass, cell abundance, and taxonomic composition. Microcosm experiments were performed in the spring, summer, and winter in the Comau Fjord located in Subantarctic Patagonia. At the end of the experiments, NO3 ? decreased rapidly and was undetectable in treatments, indicating a strong NO3 ? deficiency associated with an exponential increase in Chl-a concentrations, particulate organic nitrogen, and carbon in these treatments. Moreover, given the depleted nitrate concentrations of the spring and summer experiments, the micro-phytoplankton taxa structure shifted from mixed diatom and dinoflagellate assemblages (Ceratium spp., Dinophysis spp., Coscinodiscus sp., Rhizosolenia pungens) to assemblages dominated by blooms of the classic chain-forming diatoms found in temperate and cold waters such as Chaetoceros spp., Skeletonema spp., and Thalassiosira spp. Thus, nitrogen sources (i.e., nitrate, ammonia) may influence phytoplankton abundance and biomass accumulation dynamics in the northern section of Patagonia. It also emphasizes the importance of diatom taxa in regards to the short-term response of phytoplankton to changing environmental nutrient conditions due to natural (decreasing freshwater stream flow) and anthropogenic (aquaculture) events. This situation may be one of the future scenarios in the Patagonian fjords, thus stressing the needs for active environmental monitoring and impact assessment. 相似文献