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951.
It has been proposed that blue colouration in eggs has evolved as a signal of female quality that males can use to modulate
their parental investment. This hypothesis is based in the antioxidant properties of biliverdin whose costly deposition in
the eggshell is expected to signal female antioxidant capacity and egg quality. Since maternally derived androgens are costly
to produce and may adaptively affect offspring phenotype, high-quality females may benefit by signalling their androgen investment
through egg colouration. Our aim was to investigate whether egg colour variation in the spotless starling reflected the amount
of pigments on the eggshell and whether egg pigmentation was related to female and egg quality. Chromatography analyses revealed
that spotless starling eggshells contained two different pigments: biliverdin and protoporphyrin IX with no correlation between
them. Biliverdin contents correlated positively with egg colouration indicating that darker eggs with a higher peak in the
blue–green segment of the spectrum contained higher amounts of biliverdin. Eggs containing more biliverdin were laid by high-quality
females and contained higher yolk testosterone levels. However, despite the strong correlation between biliverdin and colorimetric
variables, egg colouration did not reflect accurately female and egg quality. Our results provide evidence that eggshell pigmentation
in the spotless starling is related to female and egg quality as shown by the yolk testosterone levels. However, the lack
of relation between egg colour and female condition and egg quality do not provide evidence to support the signalling function
of egg colouration. 相似文献
952.
Pre-spawning reproductive biology and population structure of the sea cucumber Isostichopus fuscus were analysed at the Caamaño Island, Galápagos Islands, Ecuador on a monthly basis between January 1995 and June 1996. An average of 25 individuals of all sizes were collected each month. Using microscopic characteristics of the gonads three gonadal stages were described: (1) immature; (2) mature, and (3) spent. Mature individuals showed statistically different morphometric characteristics. I. fuscus was continuously sexually mature throughout the year independent of changes in sea water temperature. Mean oocyte diameter indicated planktotrophic larval development. Mean fecundity for this species was 567,884 (±95,528 SE) eggs per gonad. Size at first maturity was between 161.0 and 170.9 g drained weight and the smallest individual found with mature gonads had a drained weight between 121.0 and 130.9 g. The population sampled ranged between 13 and 31 cm (81.0–400.0 g) with less than 10% of the population of individuals ≥25 cm (≥300.0 g). No juveniles were recorded. 相似文献
953.
Agnar Ingólfsson 《Journal of Coastal Conservation》2007,11(2):75-90
The Environmental Impact Assessment (EIA) project instigated in connection with the near-closure of the large fjord-like lagoon Gilsfjörður in sub-arctic western Iceland with a road is described and discussed. Three phases were involved: a survey of pre-impact conditions of areas possibly affected as well as control areas, predictions of impacts of the road, and assessment of impacts up to 5–6 years after completion of the project. Emphasis was placed on birds and benthic flora and fauna. Although several predictions were upheld, others were not. The most unexpected changes were the elimination of kelp forest and some associated fauna inside the road as well as from large areas outside it. Feeding areas of the knot (Calidris canutus) and female eiders (Somateria mollissima) with ducklings also changed in unexpected ways. Unforeseen changes can partly be traced to inadequate knowledge of communities and their functioning in the area. The ecological requirements of many species involved, e.g. with respect to salinity, were imperfectly known. The predictions of engineers on the effects of the project on physical factors were not as accurate or detailed as desired. Some critical predictions of the engineers failed to make an impact on the ecologists, who then failed to predict some major changes in the biota, such as the disappearance of kelp forest outside the road. This study highlights some problems probably shared by many EIAs: (a) the near impossibility of finding suitable control areas, (b) the lack of ecological understanding of even common species, and possibly (c) inadequate communication between engineers and ecologists. 相似文献
954.
Odón R. Sánchez-Ccoyllo Leila Droprinchinski Martins Rita Y. Ynoue Maria de Fátima Andrade 《Environmental Fluid Mechanics》2007,7(2):95-119
The main sources of reactive hydrocarbons (RHC) and nitrogen oxides (NOx), ozone precursors, in the Metropolitan Area of São Paulo (MASP) in the southeast of Brazil are emissions from vehicles fleets. Ambient surface ozone and particulate matter concentrations are air quality problem in the MASP. This study examined the impact that implementing a control program for mobile emissions has on ozone concentrations, An episode of high surface ozone concentrations occurring in the MASP during the March 13–15, 2000 period was used as a case study that was modeled for photochemical oxidants using the California Institute of Technology/Carnegie Mellon University three-dimensional photochemical model. Different scenarios were analyzed in relationship to the implementation of the Programa Nacional de Controle de Poluição por Veículos Automotores (PROCONVE, National Program to Control Motor Vehicle Pollution). Scenario 1 assumed that all vehicles were operating within PROCONVE guidelines. Scenarios 2 and 3 considered hypothetical situations in which the PROCONVE was not implemented. Scenario 2 set the premise that vehicles were using pre-1989 technology, whereas scenario 3 allowed for technological advances. A base case scenario, in which the official emission inventory for the year 2000 was employed, was also analyzed. The CIT model results show agreement with most measurements collected during 13–15 March 2000 modeling episode. Mean normalized bias for ozone, CO, RHC and NO x are approximately 9.0, 6.0, ?8.3, 13.0%, respectively. Tropospheric ozone concentrations predicted for scenario 2 were higher than those predicted for scenarios 1, 3 and base case. This study makes a significant contribution to the evaluation of air quality improvement and provides data for use in evaluating the economic costs of implementing a program of motor vehicle pollution control aimed at protecting human health. 相似文献
955.
956.
957.
Karina A. Rìos-Montes Roberto Briones-Gallardo Gustavo Peñuela 《Journal of environmental science and health. Part. B》2017,52(4):274-281
The most efficient system of horizontal subsurface flow constructed wetlands (HSSFCW) for removing dissolved organic carbon (DOC) in the presence of chlorothalonil pesticide (CLT) present in synthetic domestic wastewater was determined using the macrophyte Phragmites australis. Two concentrations of CLT (85 and 385 μg L?1) and one concentration of glucose (20 mg L?1) were evaluated in four pilot scale horizontal surface flow constructed wetlands coupled with two sizes of silica gravel, igneous gravel, fine chalky gravel (3.18–6.35 mm), coarse gravel (12.70–25.40 mm) and two water surface heights (20 and 40 cm). For a month, wetlands were acclimated with domestic wastewater. Some groups of bacteria were also identified in the biofilm attached to the gravel. In each treatment periodic samplings were conducted in the influent and effluent. Chlorothalonil was quantified by gas chromatography (GC-ECD m), DOC by an organic carbon analyzer and bacterial groups using conventional microbiology in accordance with Standard Methods. The largest removals of DOC (85.82%–85.31%) were found when using fine gravel (3.18–6.35 mm) and the lower layer of water (20 cm). The bacterial groups quantified in the biofilm were total heterotrophic, revivable heterotrophic, Pseudomonas and total coliforms. The results of this study indicate that fine grain gravel (3.18–6.35 mm) and both water levels (20 to 40 cm) can be used in the removal of organic matter and for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT in HSSFCW. 相似文献
958.
Sunflower Oil Industry By-product as Natural Filler of Biocomposite Foams for Packaging Applications
Versino Florencia López Olivia V. García María Alejandra 《Journal of Polymers and the Environment》2021,29(6):1869-1879
Journal of Polymers and the Environment - The use of agroindustry by-products as reinforcements and/or composites filler is an innovative and economically attractive option that is still under... 相似文献
959.
Irene Iniesta-Arandia Federica Ravera Stephanie Buechler Isabel Díaz-Reviriego María E. Fernández-Giménez Maureen G. Reed Mary Thompson-Hall Hailey Wilmer Lemlem Aregu Philippa Cohen Houria Djoudi Sarah Lawless Berta Martín-López Thomas Smucker Grace B. Villamor Elizabeth Edna Wangui 《Ambio》2016,45(3):383-393
This synthesis article joins the authors of the special issue “Gender perspectives in resilience, vulnerability and adaptation to global environmental change” in a common reflective dialogue about the main contributions of their papers. In sum, here we reflect on links between gender and feminist approaches to research in adaptation and resilience in global environmental change (GEC). The main theoretical contributions of this special issue are threefold: emphasizing the relevance of power relations in feminist political ecology, bringing the livelihood and intersectionality approaches into GEC, and linking resilience theories and critical feminist research. Empirical insights on key debates in GEC studies are also highlighted from the nine cases analysed, from Europe, the Americas, Asia, Africa and the Pacific. Further, the special issue also contributes to broaden the gender approach in adaptation to GEC by incorporating research sites in the Global North alongside sites from the Global South. This paper examines and compares the main approaches adopted (e.g. qualitative or mixed methods) and the methodological challenges that derive from intersectional perspectives. Finally, key messages for policy agendas and further research are drawn from the common reflection. 相似文献
960.
Eduardo Hernández-Miranda José Cisterna Ernesto Díaz-Cabrera Rodrigo Veas Renato A. Quiñones 《Marine Biology》2014,161(3):681-696
On February 27, 2010, the world’s sixth strongest earthquake on record (8.8 M w) and tsunami hit central Chile. We assess the response of the epibenthic macrofaunal community following this event in Coliumo Bay, one of the areas most affected by this mega-perturbation. The indicators of aggregate and compositional variability show that 3 years after this event, the community appears to have undergone the following dynamics: (1) At an inter-annual timescale, the community (both in density and biomass) shifted through different structures with apparent directionality; (2) Oceanographic and biological seasonality had a strong cyclical influence on the inter-annual community response; (3) There was spatial homogenization of the community over time (i.e., recovery of diversity), probably promoted by the ecological functionality of scavenger species (i.e., crab Cancer coronatus and snail Nassarius spp.) and by the proportional increase in non-dominant species; (4) Bathymetry and bottom dissolved oxygen also played significant roles in the spatial structure of this community; (5) Three years after the perturbation, total density and total community biomass were still considerably below those described under unperturbed conditions, mainly associated with the decrease in density and biomass of dominant species. Therefore, in spite of this apparent community compositional recovery, the aggregate variability currently remains below the levels reported prior to the effect of the mega-earthquake and tsunami. These results provide evidence that supports both the Cross-Scale Resilience Hypothesis and the Response Diversity Hypothesis. 相似文献