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81.
National and international efforts to develop natural capital accounts are proliferating. The newly agreed 2030 Agenda for Sustainable Development echoes these efforts. Continued cooperation is needed to overcome key scientific and policy challenges.  相似文献   
82.
This paper examines the relationship between economic growth and environmental degradation in Ecuador from 1971 to 2010. We estimate this relationship in a country with a heavy reliance on revenue from the exploitation of natural resources, the depletion of vegetation cover in recent decades and a low level of participation of industry in GDP. We show the existence of an inverse relationship between real GDP and vegetation cover, indicating that the output of this country is based on environmental degradation. Through Johansen co-integration tests, we check that there is a relationship of long-term equilibrium between the first differences of real GDP, vegetal cover and the urbanization rate. The ECM shows that there is a short-term relationship between vegetation cover, the GDP and the rate of urbanization. Finally, we did not found Granger causality between the variables. A policy implication based on our findings is that policies to protect the environment should not jeopardize economic growth and not limit the rapid urbanization in the country.  相似文献   
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Terrascope is a freshman learning community at the Massachusetts Institute of Technology (MIT) in which teams of students work to find solutions to large ‘unsolvable’ problems and to communicate about those problems with a wide variety of audiences in multiple formats. The program strongly promotes students’ autonomy in focusing and structuring their work, and student projects culminate in public presentations, both to general audiences and to panels of technical specialists. Students who have completed the program tend to show strong engagement with environmental and sustainability issues, as well as the skills and experience to work intensively on such issues within multidisciplinary teams. Here, we present the program as a case study, with some discussion of the factors that are key to its operation.
Ari W. EpsteinEmail:
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84.
Long-lived species are particularly susceptible to bioaccumulation of lead in bone tissues. In this paper we gain insights into the sublethal effects of lead contamination on Egyptian vultures (Neophron percnopterus). Our approach was done on the comparison of two populations (Canary Islands and Iberian Peninsula) differing in exposures to the ingestion of lead ammunition. Blood lead levels were higher in the island population (Canary Islands range: 5.10-1780 μg L−1n = 137; Iberian Peninsula range: 5.60-217.30 μg L−1n = 32) showing clear seasonal trends, peaking during the hunting season. Moreover, males were more susceptible to lead accumulation than females. Bone lead concentration increased with age, reflecting a bioaccumulation effect. The bone composition was significatively altered by this contaminant: the mineralization degree decreased as lead concentration levels increased. These results demonstrate the existence of long-term effects of lead poisoning, which may be of importance in the declines of threatened populations of long-lived species exposed to this contaminant.  相似文献   
85.
Genotoxic damage was evaluated in 70 agricultural workers, 25 women and 45 men, exposed to pesticides in Las Grullas, Ahome, Sinaloa, Mexico, with an average of 7 years of exposure. The effect was detected through the sister chromatid exchanges (SCE) in lymphocytes of peripheral blood and micronuclei (MN) and other nuclear anomalies (NA) in buccal exfoliated cells. Also, the influence on cellular proliferation kinetics (CPK) was studied by means of the replication index (RI) and the cytotoxic effect was examined with the mitotic index (MI). The non-exposed group consisted of 70 other persons, 21 women and 47 men from the city of Los Mochis, Sinaloa, Mexico. Significant differences between the exposed and the non-exposed groups were observed in SCE, CPK, MI, MN and NA. Analysis of variance revealed that age, gender, smoking and alcohol consumption did not have a significant effect on genetic damage. However, there was a correlation between exposure time to pesticides and SCE frequency. These results could have been due to the exposure of workers to pesticides containing different chemical compounds. This study afforded valuable data to estimate the possible risk to health associated with pesticide exposure.  相似文献   
86.
The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants,whose effluents flow into aquatic environments;concentrations in the 0.1-100 ng/L range are commonly found in surface waters,and its fate is unknown.Here,biological,photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time.The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin(2 μg/L) in less than 6 hr,but indomethacin was detected over a period of 4 months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited,as occurs inside a body of water.The biological degradation in water was negligible,while the hydrolysis at pH 7.8 was slow.Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction,and six degradation products were found;their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra.4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products,persisting for at least 30 weeks in water kept under non-stress conditions.Furthermore,the degradation in the presence of sediment was also monitored over time,with some differences being noted.The adsorption coefficients of indomethacin and degradation products on river sediment were calculated;long-term degradation products did not have significant adsorption to sediment.  相似文献   
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The genus Callinectes encompasses 16 species of commercially important swimming crabs. Most (13) occur on the Pacific and Atlantic coasts of the Americas. We compare mtDNA regions corresponding to 964 basepairs of the large (16S) and small (12S) ribosomal subunits among American Callinectes in order to examine phylogenetic relationships. The status of Callinectes affinis Fausto-Filho and Callinectes maracaiboensis Taissoun is questioned, and C. maracaiboensis is concluded to be a junior synonym of Callinectes bocourti A. Milne-Edwards, from which it cannot be consistently distinguished. We find two major lineages, one of which includes C. affinis, C. bocourti, Callinectes rathbunae Contreras, Callinectes sapidus Rathbun, and Callinectes toxotes Ordway. A second lineage is comprised of Callinectes arcuatus Ordway, Callinectes bellicosus (Stimpson), Callinectes danae Smith, Callinectes exasperatus (Gerstaecker), Callinectes larvatus Ordway, Callinectes ornatus Ordway, and Callinectes similis Williams. Definition of these clades is supported by previously described morphological differences in the length of the gonopods and shared physioecological adaptations. A calibrated molecular clock is used to estimate divergence of the two lineages near 13 mybp. Our analyses suggest that C. ornatus is the closest relative of C. arcuatus, and that C. affinis is closest to C. bocourti.  相似文献   
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