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991.
Specific ecogenetic features of solods in the forest-steppe zone has been studied, and the role of biotic and abiotic factors of soil formation has been estimated. Differentiation of soil horizons with respect to the physical clay fraction accounts for specific features of their moistening, which is reflected in the ratio of strongly and weakly crystallized forms of iron. Periodic changes in redox conditions results in iron segregation, and a high content of fulvic acids accounts for its eluvial migration. These processes are controlled by soil geochemical barriers. 相似文献
992.
The composition of pied flycatcher (Ficedula hypoleuca Pall.) nestling diet was studied in the zone of strong pollution with emissions from the Middle Ural Copper Smelter (Revda,
Sverdlovsk oblast) and in the background area from 2005 to 2007. The results show that diversity of the diet decreases and
prevalence in it of one insect taxon (Lepidoptera) increases near the source of emissions. The proportion of uncharacteristic
food objects (orthopterans, herpetobiont invertebrates) and variation in the size of invertebrates brought by parents to their
nestlings increase, which is explained by degradation of forest habitats in the polluted area. Pied flycatchers provide nestlings
with sufficient quantities of food, but its quality in the polluted zone is lower than in the background area. 相似文献
993.
Daniel Q. Tong Nicholas Z. Muller Haidong Kan Robert O. Mendelsohn 《Environment international》2009,35(8):1109-1117
Human exposure to ambient ozone (O3) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source–receptor relationships between nitrogen oxides (NOx) emissions and population exposure to ambient O3 in 48 states over the continental United States. By removing NOx emissions from each state one at a time, we calculate the change in O3 exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source–receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NOx emissions from upwind states contribute more to O3 exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O3 exposures in 90% of U.S. states. A state's NOx emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O3 exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O3 exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NOx is equal. In this study, the average O3 exposures caused by one ton of NOx emissions ranges from ? 2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NOx emissions varies considerably over space. 相似文献
994.
One of the major consequences of global warming is a rise in sea surface temperature which may affect the survival of marine
organisms including phytoplankton. Here, we provide experimental evidence for heat-induced cell death in a symbiotic microalga.
Shifting Symbiodinium microadriaticum from 27 to 32°C resulted in an increase in mortality, an increase in caspase 3-like activity, and an increase in nitric oxide
(NO) production. The caspase-like activity was strongly correlated with the production of NO in thermally challenged microalgae.
For this experiment, the application of Ac-DEVD-CHO, a mammalian caspase 3-specific inhibitor, partly prevented (by 65%) the
increase in caspase-like activity. To verify the relationship between NO and the caspase-like activity, S. microadriaticum were subsequently incubated with 1.0 mM of the following chemical NO donors: sodium nitroprusside (SNP), S-nitrosoglutathione (GSNO), S-nitroso-N-acetylpenicillamine (SNAP) and 3,3bis(Aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18). The supplementation of both SNP and
NOC-18 caused a significant increase in caspase-like activity compared to the control treatment. Pre-treatment of the microalgae
with the inhibitor Ac-DEVD-CHO before the supplementation of the different NO donors completely prevented the increase in
caspase-like activity. These results suggest that NO could play a role in the induction of cell death in heat-stressed S. microadriaticum by mediating an increase in caspase-like activity. 相似文献
995.
Payments for Environmental Services in Latin America as a Tool for Restoration and Rural Development
Payments for Environmental Services (PES) can encourage projects that enhance restoration, production, and rural development.
When projects promote differentiated systems by paying farmers for the provision of services, the application of PES requires
evaluation of the environmental services provided by each system. We present evaluations of carbon stocks and biodiversity
in pure and mixed native tree plantations in Costa Rica. To illustrate how monetary values can be assigned, we discuss a project
that awarded PES to silvopastoral systems in Costa Rica, Nicaragua, and Colombia based on carbon stocks and biodiversity.
PES can promote positive environmental attitudes in farmers. Currently this project is being scaled up in Colombia based on
their positive experiences with PES as a tool to promote adoption. Compared to PES systems that include only one environmental
service, systems that incorporate bundling or layering of multiple services can make sustainable land uses more attractive
to farmers and reduce perverse incentives. 相似文献
996.
A. O. Oyeyiola C. M. Davidson K. O. Olayinka T. O. Oluseyi B. I. Alo 《Environmental monitoring and assessment》2013,185(3):2167-2177
Surface sediments collected from the Lagos Lagoon, Nigeria, and three adjoining rivers were analysed for their physicochemical properties and pseudo-total concentration of the potentially toxic metals (PTM) Cd, Cr, Cu, Pb and Zn. The concentration of the PTM varied seasonally and spatially. Odo-Iyaalaro was observed to be the most polluted river, with highest concentrations of 42.1 mg kg?1, 102 mg kg?1, 185 mg kg?1, 154 mg kg?1 and 1040 mg kg?1 of Cd, Cr, Cu, Pb and Zn, respectively, while Ibeshe River was the least contaminated, apart from a site affected by Cu from the textile industry. Some of the sediments were found to be above the consensus-based probable effect concentrations and Dutch sediment guideline for metals. Overall metal concentrations were similar to those reported for other tropical lagoon and estuarine systems affected by anthropogenic inputs as a result of rapid urbanisation. Due to the large number of samples, principal component analysis was used to examine relationships within the data set. Generally, sediments collected during the dry season were observed to have higher concentration of PTM than those collected during the rainy season. This means that PTM could accumulate over a prolonged period and then be released relatively rapidly, on an annual basis, into tropical lagoon systems. 相似文献
997.
Merlin Aydın Hale Tozlu Sebnem Kemaloglu Ayse Aytac Guralp Ozkoc 《Journal of Polymers and the Environment》2011,19(1):11-17
In this study, the influence of alkali (NaOH) treatment on the mechanical, thermal and morphological properties of eco-composites
of short flax fiber/poly(lactic acid) (PLA) was investigated. SEM analysis conducted on alkali treated flax fibers showed
that the packed structure of the fibrils was deformed by the removal non-cellulosic materials. The fibrils were separated
from each other and the surface roughness of the alkali treated flax fibers was improved. The mechanical tests indicated that
the modulus of the untreated fiber/PLA composites was higher than that of PLA; on the other hand the modulus of alkali treated
flax fiber/PLA was lower than PLA. Thermal properties of the PLA in the treated flax fiber composites were also affected.
Tg values of treated flax fiber composites were lowered by nearly 10 °C for 10% NaOH treatment and 15 °C for 30% NaOH treatment.
A bimodal melting behavior was observed for treated fiber composites different than both of neat PLA and untreated fiber composites.
Furthermore, wide angle X-ray diffraction analysis showed that the crystalline structure of cellulose of flax fibers changed
from cellulose-I structure to cellulose-II. 相似文献
998.
M. Jawaid H. P. S. Abdul Khalil P. Noorunnisa Khanam A. Abu Bakar 《Journal of Polymers and the Environment》2011,19(1):106-109
In this research, hybrid composite materials were prepared from combination of oil palm Empty fruit bunches (EFB) fibre and
jute fibre as reinforcement, epoxy as polymer matrix. This study intended to investigate the effect of jute fiber hybridization
and different layering pattern on the physical properties of oil palm EFB-Epoxy composites. Water absorption and thickness
swelling test reveal that hybrid composite shows a moderate water absorption which is 11.20% for hybrid EFB/Jute/EFB composite
and 6.08% for hybrid Jute/EFB/Jute composite. The thickness swelling and water absorption of the hybrid composites slightly
increased as the layering pattern of hybrid composites changed. Hybrid composites are more water resistance and dimensional
stable compare to the pure EFB composites. This is attributed to the more hydrophilic nature of EFB composites. Hybridization
of oil palm EFB composites with jute fibres can improve the dimensional stability and density of pure EFB and Jute fibre reinforced
composites has higher density of 1.2 g/cm3 compared to all other composites. 相似文献
999.
J. Ram Pillarisetti Jeroen C. J. M. van den Bergh 《Environment, Development and Sustainability》2010,12(1):49-62
What is a ‘sustainable nation’ and how can we identify and rank ‘sustainable nations?’ Are nations producing and consuming in a sustainable way? Although several aggregate indexes have been proposed to answer such questions, comprehensive and internationally comparable data are not available for most of these. This paper quantitatively compares three aggregate indexes of sustainability: the World Bank’s ‘Genuine Savings’ measure, the ‘Ecological Footprint,’ and the ‘Environmental Sustainability Index.’ These three indexes are available for a large number of countries and also seem to be the most influential among the aggregate indexes. This paper first discusses the main limitations and weaknesses of each of these indexes. Subsequently, it shows that rankings of sustainable nations and aggregate assessments of unsustainable world population and world GDP shares vary considerably among these indexes. This disagreement leads to suggestions for analysis and policy. One important insight is that climate change, arguable the most serious threat currently faced by humanity, is not or arbitrarily captured by the indexes. 相似文献
1000.
Romeu Casarano Denise F. S. Petri Michael Jaffe Luiz H. Catalani 《Journal of Polymers and the Environment》2010,18(1):33-44
A new aliphatic block copolyester was synthesized in bulk from transesterification techniques between poly((R)-3-hydroxybutyrate)
(PHB) and poly(isosorbide succinate) (PIS). Additionally, other two block copolyesters were synthesized in bulk either from
transesterification reactions involving PHB and poly(l-lactide) (PLLA) or from ring-opening copolymerization of l-lactide and hydroxyl-terminated PHB, as result of a previous transesterification reactions with isosorbide. Two-component
blends of PHB and PIS or PLLA were also prepared as comparative systems. SEC, MALDI-TOF mass spectrometry (MALDI-TOFMS), 1H and 13C NMR spectroscopy, WAXD, solubility tests, and TG thermal analysis were used for characterization. The block copolymer structures
of the products were evidenced by MALDI-TOFMS, 13C NMR, and WAXD data. The block copolymers and the corresponding binary blends presented different solubility properties,
as revealed by solubility tests. Although the incorporation of PIS sequences into PHB main backbone did not enhance the thermal
stability of the product, it reduced its crystallinity, which could be advantageous for faster biodegradation rate. These
products, composed of PHB and PIS or PLLA sequences, are an interesting alternative in biomedical applications. 相似文献