排序方式: 共有45条查询结果,搜索用时 15 毫秒
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Vincenzo Augugliaro Claudio Baiocchi Alessandra Bianco Prevot Elisa García-Lpez Vittorio Loddo Sixto Malato Giuseppe Marcí Leonardo Palmisano Marco Pazzi Edmondo Pramauro 《Chemosphere》2002,49(10)
The photodegradation of two common and very stable azo-dyes, i.e. methyl-orange (C14H14N3SO3Na) and orange II (C16H11N2SO4Na), is reported. The photocatalytic oxidation was carried out in aqueous suspensions of polycrystalline TiO2 irradiated by sunlight. Compound parabolic collectors, installed at the “Plataforma Solar de Almería” (PSA, Spain) were used as the photoreactors and two identical reacting systems allowed to perform photoreactivity runs for the two dyes at the same time and under the same irradiation conditions. The disappearance of colour and substrates together with the abatement of total organic carbon content was monitored. The main sulfonate-containing intermediates were found to be in lower number in respect to those obtained under artificial irradiation. In particular there were no more evidence of the presence of hydroxylated transients. The dependence of dye photooxidation rate on: (i) substrate concentration; (ii) catalyst amount; and (iii) initial pH was investigated. The influence of the presence of strong oxidant species (H2O2, S2O82−) and some ions (Cl−, SO42−) on the process was also studied. 相似文献
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Daniela Canestrari Marta Vila José M. Marcos Vittorio Baglione 《Behavioral ecology and sociobiology》2012,66(9):1225-1235
In cooperatively breeding species, parents should bias offspring sex ratio towards the philopatric sex to obtain new helpers (helper repayment hypothesis). However, philopatric offspring might increase within-group competition for resources (local resource competition hypothesis), diluting the benefits of helper acquisition. Furthermore, benefits of offspring sex bias on parents’ fitness may depend on different costs of production and/or different breeding opportunities of sons and daughters. Because of these counteracting factors, strategies of offspring sex allocation in cooperative species are often difficult to investigate. In carrion crows Corvus corone corone in northern Spain, sons are more philopatric and more helpful at the nest than daughters, which disperse earlier and have higher chances to find a breeding vacancy. Consistent with the helper repayment hypothesis, we found that crows fledged more sons in groups short of subordinate males than in groups with sufficient helper contingent, where daughters were preferred. Crow females also proved able to bias primary sex ratio, allocating offspring sex along the hatching sequence in a way that provided the highest fledging probability to sons in the first breeding attempt and to daughters in the following ones. The higher cost of producing male offspring may explain this pattern, with breeding females shifting to the cheapest sex (female) as a response to the costs generated by previous reproductive attempts. Our results suggest complex adjustments of offspring sex ratio that allowed crows to maximize the value of daughters and sons. 相似文献
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D. Pitea M. Lasagni G. Moro R. Todeschini S. Clementi G. Cruciani G. Chiesa 《Chemosphere》1990,20(10-12)
Experimental data on PCDD and PCDF emissions in raw gases from municipal solid waste combustion in a pilot plant were processed by Response Surface models to gain information on process parameter values which minimize both the total PCDD/PCDF concentrations and those of a selected congener group. 相似文献
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