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71.
Dilini Abeygunawardane Angela Kronenburg García Zhanli Sun Daniel Müller Almeida Sitoe Patrick Meyfroidt 《Ambio》2022,51(6):1535
Actor-level data on large-scale commercial agriculture in Sub-Saharan Africa are scarce. The peculiar choice of transnational investing in African land has, therefore, been subject to conjecture. Addressing this gap, we reconstructed the underlying logics of investment location choices in a Bayesian network, using firm- and actor-level interview and spatial data from 37 transnational agriculture and forestry investments across 121 sites in Mozambique, Zambia, Tanzania, and Ethiopia. We distinguish four investment locations across gradients of resource frontiers and agglomeration economies to derive the preferred locations of different investors with varied skillsets and market reach (i.e., track record). In contrast to newcomers, investors with extensive track records are more likely to expand the land use frontier, but they are also likely to survive the high transaction costs of the pre-commercial frontier. We highlight key comparative advantages of Southern and Eastern African frontiers and map the most probable categories of investment locations.Supplementary informationThe online version contains supplementary material available at 10.1007/s13280-021-01682-z. 相似文献
72.
Stefanelli P Barbini DA Girolimetti S Santilio A Dommarco R 《Journal of environmental science and health. Part. B》2011,46(4):341-349
A simple method for the determination of dimethyl fumarate (DMFu) in silica gel pouches has been developed. The gas chromatographic behaviour of DMFu was investigated; the instrumental method, based on EI mass spectrometry coupled with an Ion Trap Detector operating whether in full scan mode or in MS/MS mode was also investigated. Several factors have been evaluated and optimized during the development process: solvent and temperature of extraction, type of stationary phase in capillary column. The analytical procedure consists of two steps as follows: (a) the sample preparation using 10 g of sample extracted with acetonitrile in an ultrasonic, heated bath and (b) the determination by gas chromatography-ion trap mass spectrometry. Mass spectrometry in conjunction with chromatographic separation is a very powerful combination for identification of an analyte in the extract in spite of selective detectors employed with GC, such as ECD, FPD and NPD, that offer only limited specificity. Blank samples show no interfering peaks in the areas of interest, so the specificity of the method was assured under the investigated GC/MS conditions. The method has been validated in terms of recovery, repeatability, linearity, detection limits and measurement uncertainty. The results obtained meet both the method validation criteria and requirements of the European/National legislation. The method was verified to be accurate with 97 % mean recoveries at 0.05 mg/kg and 1.00 mg/kg levels; the repeatability (expressed as RSD %) was found to be better than 15 %. Good linearity was found in the range between 0.05 μg/mL and 5.0 μg/mL and a value of R2 > 0.9998 was calculated. The procedure ensures high specificity and a good sensitivity with detection limit (ld) of 0.02 mg/kg and quantification limit (LOQ) of 0.05 mg/kg. This procedure has been successfully applied for the analysis of several hundred of real samples collected during a monitoring control plan started last year in our country. All samples exceeding the maximum allowed level of DMFu (0, 1 mg/kg) were confirmed by GC/MS/MS (ITD) for a higher degree of confidence in identification. The main advantages of this method include: rapidity, simplicity (few, simple steps), reliability, cheapness, no need for long and difficult clean-up and evaporation steps, high specificity by using GC/MS and GC/MS/MS, availability for routine monitoring. 相似文献
73.
Angela M. Wallace Melanie V. Croft-White Jan Moryk 《Environmental monitoring and assessment》2013,185(9):7857-7875
Impacts of urbanization on aquatic ecosystems are intensifying as urban sprawl spreads across the global land base. The urban stream syndrome (USS) identifies “symptoms” associated with urban development including changes in biotic communities, hydrology, water chemistry, and channel morphology. Direct relationships between road density (as surrogate of urbanization) and indicators of the USS were identified for streams in the Toronto region. Significant negative relationships were revealed between road density and biological (fish and benthic macroinvertebrate) richness, diversity, and fish Index of Biotic Integrity scores. Significant positive relationships were found between road density and tolerant fish/benthic macroinvertbrates, benthos Family Biotic Index scores, mean summer stream temperature, stream flashiness, and several water quality variables. Analysis of biological data showed that only four fish species and a reduced number of benthic macroinvertebrate families remained at the most urbanized sites. Road density was found to be a major determinant in both the fish and benthic macroinvertebrate community structure. 相似文献
74.
Angela M. Bayer Heather E. Danysh Mijail Garvich Guillermo Gonzálvez William Checkley María Álvarez Robert H. Gilman 《Disasters》2014,38(2):351-374
During the 1997–98 El Niño, Tumbes, Peru received 16 times the annual average rainfall. This study explores how Tumbes residents perceived the impact of the El Niño event on basic necessities, transport, health care, jobs and migration. Forty‐five individuals from five rural communities, some of which were isolated from the rest of Tumbes during the event, participated in five focus groups; six of these individuals constructed nutrition diaries. When asked about events in the past 20 years, participants identified the 1997–98 El Niño as a major negative event. The El Niño disaster situation induced a decrease in access to transport and health care and the rise in infectious diseases was swiftly contained. Residents needed more time to rebuild housing; recover agriculture, livestock and income stability; and return to eating sufficient animal protein. Although large‐scale assistance minimized effects of the disaster, residents needed more support. Residents' perspectives on their risk of flooding should be considered in generating effective assistance policies and programmes. 相似文献
75.
The potential of purple non-sulphur bacteria for bioremediation was assessed by investigating the ability of Rhodobacter sphaeroides strain R26.1 to grow photosynthetically in heavy metal contaminated environments. Bacterial cultures were carried out in artificially polluted media, enriched with the transition metal ions Hg2+, Cu2+, Fe2+, Ni2+, Co2+, MoO4(2-), and CrO4(2-) in millimolar concentration range. For each investigated ion the effect on growth parameters was evaluated. The analysis of concentration-effect curves revealed a differentiated response, indicating that diverse mechanisms of tolerance and/or resistance are involved. Adaptation or selection procedures were not applied, leading to assess intrinsic abilities of coping with these contaminants. The microorganism proved to be highly tolerant to heavy metal exposure, especially towards Co2+, Fe2+ and MoO4(2-). In addition Ni2+ and Co2+ were found to decrease the cellular content of light harvesting complexes. A characteristic behavior was observed with mercuric ions, which produced a significant increase of the lag-phase. 相似文献
76.
77.
Sandrin CZ Figueiredo-Ribeiro Rde C Carvalho MA Delitti WB Domingos M 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):915-921
This study analyzed the relationship between environmental factors, especially air pollution and climatic conditions, and non-structural carbohydrates (NSC) in plants of Lolium multiflorum exposed during 10 consecutive periods of 28 days at a polluted site (Congonhas) and at a reference site in São Paulo city (Brazil). After exposure, NSC composition and leaf concentrations of Al, Fe, Cu, Zn, Pb and Cd were measured. The seasonal pattern of NSC accumulation was quite similar in both sites, but plants at Congonhas showed higher concentrations of these compounds, especially fructans of low and medium degree of polymerization. Regression analysis showed that NSC in plants growing at the polluted site were explained by variations on temperature and leaf concentration of Fe (positive effect), as well as relative humidity and particulate material (negative effect). NSC in the standardized grass culture, in addition to heavy metal accumulation, may indicate stressing conditions in a sub-tropical polluted environment. 相似文献
78.
79.
Philip Drake Angela Smith 《Environmental Communication: A Journal of Nature and Culture》2016,10(6):689-703
ABSTRACTThis article considers the format and cultural politics of the hugely successful UK television program Top Gear (BBC 2002–2015). It analyzes how—through its presenting team—it constructed an informal address predicated around anti-authoritarian or contrarian banter and protest masculinity. Regular targets for Top Gear presenter’s protest—curtailed by broadcast guidelines in terms of gender and ethnicity—are deflected onto the “soft” targets of government legislation on environmental issues or various forms of regulation “red tape. Repeated references to speed cameras, central London congestion charges and “excessive” signage are all anti-authoritarian, libertarian discourses delivered through a comedic form of performance address. Thus, the BBC’s primary response to complaints made about this program was to defend the program’s political views as being part of the humor. The article draws on critical discourse analysis and conversation analysis to consider how the program licensed a particular form of engagement that helped it to deflect criticisms, and considers the limits to such discursive positioning. We conclude by examining the controversies that finally led, in 2015, to the removal of the main presenter, Jeremy Clarkson, and the ending of this version of the program through the departure of the team to an on-demand online television service. 相似文献
80.