Homogeneous Catalytic Ozonation of Lipids Involving Fe2+ and Mn2+: An Experimental and Modeling Study     

Rúbia Martins Bernardes Ramos  Ana Paula Biz  Deolinda Alvarez Tavares  Mnica Beatriz Kolicheski  Tirzh Lins Porto Dantas 《洁净——土壤、空气、水》2020,48(7-8)

Given the issue of lipids in effluent treatment systems and their negative impact on the environment, this study aimed to examine lipid degradation by homogenous catalytic ozonation with the aid of iron and manganese ions. This technology presents the possibility of completely mineralizing pollutants using hydroxyl radicals. Milk is chosen as the lipid source because of the high concentration of triglycerides in its matrix, this kind of lipid being the one found most frequently in food and, consequently, in effluent treatment systems. The milk pH value is controlled, and acidic, neutral, and basic conditions are evaluated. The rates of pseudo‐first‐order reactions and the effective value are estimated. It is shown that under acidic conditions low catalyst dosages are enough to cause the complete degradation of lipids. Under neutral conditions, a similar behavior is observed. Under basic conditions, higher catalyst dosages give higher reaction rates. The order of effectiveness of the catalysts under acidic and basic conditions is Fe²⁺ > Mn²⁺, with Mn²⁺ > Fe²⁺ under neutral conditions. Homogeneous catalytic ozonation is therefore efficient at lipid degradation. This technique is viable economically, since the lipid removal occurred at low ozone levels. In addition, the ions used as catalysts are naturally abundant.  相似文献   

Rethinking the dumping grounds: questioning assumptions about movement into the relocation settlement of Bilanyoni     

Paula Meth 《Area》2001,33(3):228-241

Historical accounts of relocation settlements in South Africa have emphasized processes of dispossession in the creation of these settlements. This paper considers other related histories of movement into relocation settlements as evidence of seldom considered contradictory and ambiguous experiences around movement and attachment to place — hence encouraging a rethink of the laden term 'the dumping grounds'.  相似文献   

Demersal fishes in a tropical bay in southeastern Brazil: Partitioning the spatial, temporal and environmental components of ecological variation     

Mrcia Cristina Costa de Azevedo  Francisco Gerson Araújo  Antnio Gomes da Cruz-Filho  Andr Luiz Machado Pessanha  Mrcio de Araújo Silva  Ana Paula Penha Guedes 《Estuarine, Coastal and Shelf Science》2007,75(4):468-480

This study analyzed the factors structuring demersal fish community in a tropical bay in southeastern Brazil. The results were used to quantify the partitioning of ecological variation among the environmental, spatial and temporal components molding the fish community. Three bay zones (inner, middle and outer) were defined according to depth and salinity gradient. Monthly samplings were conducted by bottom trawl tows during daylight hours, between October 1998 and September 1999. In each zone, three replicate samples were taken. Ninety-three fish species from 73 genera and 37 families were recorded in the 108 samples. Two demersal fish assemblages were evidenced, one in the inner and the other in the outer zone. These assemblages were characterized by changes in species composition and relative abundance. Depth, followed by transparency and salinity, influenced spatial pattern of fish assemblages. The largest part of the explained variation occurred as a result of the spatial structure of environmental variables, which means that both species and environmental variables presented similar spatial structure. The spatial effect, not the seasonal, explained the highest part of species variations. The amount of unexplained variation was relatively high (76%), even assuming that part of it is due to nondeterministic fluctuation, which could be due to local effects of unmeasured (biotic and abiotic) controlling variables. Knowing the relative importance of these factors can be of decisive importance when applying casual hypotheses in the framework of some precise ecological theory and should facilitate management, planning, and usage of bay resources.  相似文献   

Unbleached pulp mill effluents affect cytochrome P450 monooxygenase enzyme activities     

Pirjo Lindstrm-Sepp  Sirpa Huuskonen  Maija Pesonen  Paula Muona  Osmo Hnninen 《Marine environmental research》1992,34(1-4)

The polysubstrate monooxygenase system has been shown to be highly responsive to chemical pollution. The present study summarizes the enzyme based biomonitoring of the waste waters released by a pulp mill producing unbleached pulp and paperboard. Cytochrome P4501A enzyme activities of feral and caged fish, as well as cultures of fish hepatocytes, were tested. The 7-ethoxyresorufin-O-deethylase (EROD) activity was clearly induced in fish hepatocytes exposed to biotreated unbleached pulp mill effluent fractions in vitro. The effluent increased EROD activities also in feral perch, compared with controls. Caging experiments showed similar effects to those seen in feral fish: however, the maximal induction coefficients observed were higher. Unbleached effluents contain compounds that are able to affect the P4501A activities in fish.  相似文献   

Usefulness of microsatellite markers developed from Pagellus bogaraveo to genetically study five different species of Sparidae     

Jorge A. Piñera  David Bernardo  Gloria Blanco  Emilia Vázquez  & José A. Sánchez 《Marine Ecology》2007,28(S1):184-187

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Larval fish distribution in shallow coastal waters off North Western Iberia (NE Atlantic)   总被引：2，自引：1，他引：2  

Ulisses Miranda Azeiteiro  Leonor Bacelar-Nicolau  Paula Resende  Fernando Gonalves  Mrio Jorge Pereira 《Estuarine, Coastal and Shelf Science》2006,69(3-4):554

Monthly sampling for ichthyoplankton was conducted at three stations very near to the coast (near to shore shallow stations before the surf zone in direction to the shoreline) of Atlantic northwestern Portugal within contrasting localities: rocky shore, in front of a sandy beach receiving an estuary and a fishing port with heavy anthropogenic impact. Sampling was conducted from August 2002 to October 2003, always at full moon, at low tide and high tide in daylight hours, at the water column using a 48 cm diameter plankton net with 335 μm mesh. Analysis of the physico-chemical parameters pointed out the spatial (horizontal) homogeneity of the sampling area. Fish larvae from 41 taxa belonging to 17 families were identified; Blenniidae, Labridae, Ammodytidae, Clupeidae, Gobiidae, Soleidae and Gobiesocidae were the most representative during the study period. Parablennius gattorugine, Ammodytes tobianus, Symphodus melops, Sardina pilchardus, Lipophrys pholis and Coryphoblennius galerita were the most representative species (percentage contribution to total abundance). Peak abundance of fish eggs occurred during May, June and August 2003 and fish larvae occurred during May and July 2003 and August 2002 and 2003; there was a pronounced winter/early spring (March 2003) peak in larval abundance dominated by the small sandeel A. tobianus. This study identifies the occurrence of a conspicuous assemblage of larval fishes at very nearshore shallow environments of a variety of species with different adult habitats: the fish larvae assemblage was dominated by intertidal species. The present study has shown that temporal and spatial variations in the larval fish assemblage are related to environmental conditions and biological dynamics: the results suggest that abiotic conditions mediate biotic parameters, and that both abiotic and biotic characteristics regulated the larval fishes at very nearshore shallow environments.  相似文献   

Increasing Aridity is Enhancing Silver Fir Abies Alba Mill.) Water Stress in its South-Western Distribution Limit     

Marc Macias  Laia Andreu  Oriol Bosch  J. Julio Camarero  Emilia Gutiérrez 《Climatic change》2006,79(3-4):289-313

Tree populations located at the geographical distribution limit of the species may provide valuable information about the response of tree growth to climate warming across climatic gradients. Dendroclimatic information was extracted from a network of 10 silver-fir (Abies alba) populations in the south-western distribution limit of the species (Pyrenees, NE Iberian Peninsula). Ring-width chronologies were built for five stands sampled in mesic sites from the Main Range in the Pyrenees, and for five forests located in the southern Peripheral Ranges where summer drought is more pronounced. The radial growth of silver-fir in this region is constrained by water stress during the summer previous to growth, as suggested by the negative relationship with previous September temperature and, to a lesser degree, by a positive relationship with previous end of summer precipitation. Climatic data showed a warming trend since the 1970s across the Pyrenees, with more severe summer droughts. The recent warming changed the climate-growth relationships, causing higher growth synchrony among sites, and a higher year-to-year growth variation, especially in the southernmost forests. Moving-interval response functions suggested an increasing water-stress effect on radial growth during the last half of the 20th century. The growth period under water stress has extended from summer up to early autumn. Forests located in the southern Peripheral Ranges experienced a more intense water stress, as seen in a shift of their response to precipitation and temperature. The Main-Range sites mainly showed a response to warming. The intensification of water-stress during the late 20th century might affect the future growth performance of the highly-fragmented A. alba populations in the southwestern distribution limit of the species.  相似文献   

A Methodology for Monitoring Vertical Dynamic Sub-Centimeter Displacments with GPS     

Ricardo Ernesto Schaal  Ana Paula Camargo Larocca 《GPS Solutions》2002,5(3):15-18

This article describes a methodology to monitor dynamic vertical sub-centimeter displacement, of a GPS antenna. The dynamic movement of an antenna is determined by choosing the appropriate reference satellite for measurement differencing and by applying a FFT filter on the double-difference phase residuals. The validity of the method depends on the time variations of the GPS residuals and errors, such as, receiver noise, atmospheric contribution, multipath effects, and the antenna movement. This research is under development and results for simulated motion are presented here. ? 2002 Wiley Periodicals, Inc.  相似文献   

Geophysics and geology of an explosion crater in the Ethiopian rift valley     

D. A. Emilia  B. J. Last  C. A. Wood  F. M. Dakin 《Bulletin of Volcanology》1977,40(3):133-140

Geophysical and geological studies of an Ethiopian maar, Haro Maja, demonstrate that its eruptive history is more complex than surface geology alone suggests. The crater is 750 m by 1000 m in diameter and varies in depth from 70 m to 110 m. A strong magnetic anomaly is caused by a central basaltic mound, but a broader crater-wide anomaly is best modelled by a 50 m thick frozen lava lake, 30 m below the crater floor. The central mound was not erupted directly onto the lava lake, but was extruded onto top of the sedimentary infill after a quiescent depositional interval. Electrical resistivity measurements further indicate that other basaltic intrusions failed to reach the surface during that eruptive period.  相似文献   

Analytische geochemie in 2 bänden. Band 1 methodik. Band II Grindlagen und Anwendungen: Erich Schroll. Ferdinand Enke Verlag Stuttgart, 1975, 1976. Vol. 1, 292 pp. (DM 59, —); Vol. 2, 374 pp. (DM 69, —)     

Paula Hahn-Weinheimer 《Geochimica et cosmochimica acta》1977,41(8):1179

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