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291.
Valeria Mezzanotte Nadia Prato Sergio Sgorbati Sandra Citterio 《Water environment research》2004,76(5):463-467
Microbial populations were studied by plate counts and flow cytometry along the polishing sequence of a wastewater plant. The comparison between plate count and flow cytometry showed comparable trends, but plate counts detected less than 10% of the total intact bacteria counted by flow cytometry. Six months monitoring showed that, in spite of the high ozone doses, the disinfection effect of ozonation was insignificant. This is in agreement with the variability of ozone demand, not only related to chemical oxygen demand or total suspended solids. Membrane-intact bacterial population decreased after ozonation, slightly regrew between ozone and biological activated carbon (BAC), and sharply increased after BAC, probably for damaged bacteria regrowth and saprophytes release; BAC effluent had the highest bacterial counts. Preliminary investigations on the effluent microbial composition showed that the beta Proteobacteria subclass is the most represented in the BAC effluent, whereas the alpha subclass is the most sensitive to ozone effect. 相似文献
292.
Liquid wastes from the fish meal and oil processing industries produce serious environmental impacts in coastal embayments on the coasts of Chile and Peru. This article presents an analysis of an environmental monitoring program at Lota Bay, a shallow coastal indentation in central Chile (37 degrees S) exposed to industrial fishing activity. The study of the environmental impact produced by waste effluents permitted making an evaluation of the bay's capacity for seasonal recovery from this impact. Seasonal cruises were carried out during 1994 and in 1996, 1997, and 1998. Variables analyzed included salinity, temperature, dissolved oxygen, ammonium concentration and surface oil and grease. The hydrographic regime of Lota Bay follows a seasonal pattern, where, typical of most SE pacific embayments, waters from subsuperficial oxygen minimum zones moved into the bay. The percentages of dissolved oxygen were critical in the area of organic waste discharge. The impact of wastewater is related to the type and status of the fishery, including: (i) overloads of plant production lines, (ii) maintenance and cleaning of installations, and (iii) degree of shipboard fishing conservation. Major alterations were observed in summer, when the highest discharge of organic load occurred. In winter, an improvement in the re-aeration conditions reduced the impact. Remedial measures implemented beginning in 1997 arose from the monitoring program and had to be separated into two recovery factors including (a) internal management of plants and (b) treatment of plant effluents. 相似文献
293.
Georgios Tsounis Sergio Rossi Maria Aranguren Josep-Maria Gili Wolf Arntz 《Marine Biology》2006,148(3):513-527
Red coral (Corallium rubrum, L. 1758) is an over-exploited Mediterranean gorgonian. The gonadal development cycle of this gorgonian is examined at the
Costa Brava (NW Mediterranean) taking into account for the first time colony size, depth and spatial horizontal variability.
This study compares the gonad development and fertility in two colony size classes (colonies <6-cm height, and >10-cm height,
both at 40–45-m depth), and two populations at different depths (16–18-m depth, and 40–45-m depth, both consisting of <6-cm
high colonies) in a 15-month period. The fertility of seven size classes (<2 cm to >12 cm high colonies, in 2 cm intervals)
was examined in the deep population, where large colonies were present. Furthermore, reproductive output was compared in 6
populations (distributed along more than 70-km coastline) one month before spawning (June). Red coral was found to be dioecious
and gonochoric with a sex ratio of 1:1, which differs from other NW Mediterranean populations. On the other hand, fertility
of different size classes indicates that small colonies of 2-cm height already produce gonads, which is in line with previous
studies. Female and male polyp fertility and sperm sac size increase significantly with colony size [sperm sac diameter: 476±144 μm
(mean±SD) and 305±150 μm in the >10-cm and <6-cm height colonies, respectively), whereas no significant effect on oocyte diameter
was found (oocyte diameter: 373.7±18.7 μm). Depth staggered spawning, that is, an earlier release of gonads in the shallow
populations, was observed in summer 2003, coinciding with the highest temperature gradient between shallow and deep water
during the study period. Colonies of <6-cm height were significantly less fertile than colonies >12 cm, thus the recommendation
of this study is that a minimum height should be incorporated into fishing regulations. The six studied populations at the
Costa Brava showed a comparable reproductive potential, which demonstrates little variability within the homogenous population
structure and range of size classes (due to overharvesting) found at the Costa Brava. The study of reproductive output is
an important tool for ecosystem management, and this work recommends basing specific exploitation laws for distinctive populations
on colony size, which is found to have a larger effect on reproductive potential than mesoscale variability.
An erratum to this article can be found at 相似文献
294.
Xiuhua Wang Carol Seaman Myunghee Paik Timothy Chen Arthur Bank Sergio Piomelli M.D. 《黑龙江环境通报》1994,14(9):851-857
Prenatal diagnosis of sickle cell diseases is obtained rapidly and precisely by polymerase chain reaction (PCR) with Ddel restriction analysis and dot-blotting with alllele-specific oligonucleotides (ASO). Prenatal diagnosis of HgbSS and HgbSC was performed in 500 pregnancies, 196 by Southern blot and 304 by PCR. PCR drastically shortened the interval from sampling to reporting, allowing acceptance even of samples with unknown paternal phenotype, and resulted in an overall four-fold increase in diagnoses. In 108 pregnancies, the diagnosis was an affected fetus; 25 were HgbSC: 3 (12 per cent) were terminated; 83 were HgbSS: four ended in miscarriage; 40/79 (51 per cent) were terminated. The gestational age at the time of report to the mother appeared to be a major outcome determinant when the fetal diagnosis was HgbSS. The change-point in the maternal decision was found at 20 weeks of gestation. Before the 20th week, most mothers (64 per cent) chose termination; thereafter, the majority (72 per cent) chose continuation. The odds ratio of termination in earlier relative to later reporting was 4·7. In order to offer a choice to the mothers at risk of delivering a fetus affected by sickle cell disease, the diagnosis should be reported before the 20th week of gestation. 相似文献
295.
Summary. Orb-web-spiders present a series of different strategies for prey capture, involving the use of different types of silk for
web building, the use of adhesive traps in the webs, the secretion of toxic compounds to the spider’s preys in the adhesive
coating of the capture web and the biosynthesis of a wide range of structurally related acylpolyamine toxins in their venoms.
The polyamine toxins usually block neuromuscular junctions and/or the central nervous system (CNS) of Arthropods, targeting
specially the ionotropic glutamate receptors; this way these toxins are used are as chemical weapons to kill / paralyze the
spider’s prey. Polyamine toxins contain many azamethylene groups involved with the chelation of metal ions, which in turn
can interact with the glutamate receptors, affecting the toxicity of these toxins. It was demonstrated that the chelation
of Ni+2, Fe+2, Pb+2, Ca+2 and Mg+2 ions by the desalted crude venom of Nephilengys cruentata and by the synthetic toxin JSTX-3, did not cause any significant change in the toxicity of the acylpolyamine toxins to the
model-prey insect (honeybees). However, it was also reported that the chelation of Zn+2 ions by the acylpolyamines potentiated the lethal / paralytic action of these toxins to the honeybees, while the chelation
of Cu+2 ions caused the inverse effect. Atomic absorption spectrometry and Plasma-ICP analysis both of N. cruentata venom and honeybee’s hemolymph revealed that the spider’s venom concentrates Zn+2 ions, while the honeybee’s hemolymph concentrates Cu+2 ions. These results are suggesting that the natural accumulation of Zn+2 ions in N. cruentata venom favors the prey catching and/or its maintenance in the web, while the natural accumulation of Cu+2 ions in prey’s hemolymph minimizes the efficiency of the acylpolyamine toxins as killing/paralyzing tool. 相似文献
296.
Susana L. H. Rebelo A. Melo R. Coimbra M. Emília Azenha Mariette M. Pereira Hugh D. Burrows Mohamed Sarakha 《Environmental Chemistry Letters》2007,5(1):29-33
The photodegradation of the herbicides atrazine and ametryn with visible light in aerated neutral aqueous solutions and 5,
10, 15, 20-tetrakis (2,6-dichloro-3-sulfophenyl) porphyrin or 5, 10, 15, 20-tetrakis (4-sulfophenyl) porphyrin as sensitizers
are reported for the first time. Our findings show that the degradation percentage reached 30% for atrazine and 63% for ametryn.
The final photoproducts were characterized as dealkylated s-triazines. Photolysis of the pesticides in the presence of a singlet oxygen quencher showed only a minor contribution of
this type of mechanism, while a bimolecular quenching reaction between the triplet state of the sensitizer and the pesticides
is excluded by flash photolysis studies. It is proposed that the mechanism may involve the formation of a superoxide radical
anion from the triplet state of the sensitizer and molecular oxygen, followed by a radical decomposition pathway.
Selected article from 1st International Meeting on Photochemistry, Photocatalysis and Environmental Applications, Agadir,
2006, organised by Prof. Dr. Ait Ichou, University Ibn Zohr, Agadir, Morocco 相似文献
297.
Andrea Gori Cristina Linares Sergio Rossi Rafel Coma Josep-Maria Gili 《Marine Biology》2007,151(4):1571-1584
Paramuricea clavata (Risso, 1826) and Eunicella singularis (Esper, 1794) are the most representative gorgonian species in hard bottoms sublittoral communities in the Western Mediterranean
Sea. Reproductive cycles of two populations of both species were studied in two distinct locations approximately 600 km apart
(Medes Islands and Cape of Palos), in order to assess interpopulation variability on a relevant geographic scale. Seasonal
variation of lipid concentration levels in the gorgonian tissue was used as a tool to quantify energy storage by each studied
population in order to explain possible interpopulation differences in gonadal output. Sex ratio in Medes Islands populations
of both species was 1:1, while in Cape of Palos sex ratio was significantly male biased (1:7) in P. clavata, and female biased (1.7:1) in E. singularis populations. Spawning timing occurred in all cases coinciding with a marked increase in sea-water temperature in spring,
and after the most successful feeding season, but comparing localities there was a clear temporal shift in the time of gametes
release, appearing well linked to the shift in sea-water temperature rising in spring in both sites at the depth where populations
are placed. Therefore, in this study the temperature appears as the main synchronizing factor of gonadal development within
these populations. Significant differences in gonadal volume per polyp were found in both species owing mainly to differences
in the number of gonads per polyp between populations, with Cape of Palos populations displaying higher values in both studied
species, suggesting that the exposition to different local conditions may be reverted in a different gonadal output. But the
observed patterns in lipid concentrations levels in gorgonians disable us to conclude that lipid concentration levels explain
the observed differences in gonadal output found in this study. 相似文献
298.
299.
Susana de Melo Abreu Paulo Herbert Pierluigi Caboni Paolo Cabras Arminda Alves Vincenzo Luigi Garau 《Journal of environmental science and health. Part. B》2013,48(7):817-822
Fenamidone is an imidazolinone fungicide recently introduced in viticulture practices. This work reports the validation and assessment of global uncertainty of a gas chromatographic with mass spectrometry method to analyze fenamidone in grapes and wines. This method consists in a simple and fast liquid-liquid extraction step followed by chromatographic determination. Limits of detection for fenamidone in grapes and wines were, respectively, 0.05 mg/kg and 0.06 mg/L, precision was below 9.4% and average recovery was 89 ± 5%. In the concentration range from 0.05 to 1.00 mg/kg (or mg/L) of fenamidone, global uncertainty calculated following the EURACHEM/CITAC rules, and also by the Horwitz function, was below 25%. The EURACHEM/CITAC global uncertainty budget used gave lower estimates than those obtained from the Horwitz function. 相似文献
300.
Potential fecundity in Loligo vulgaris reynaudii was estimated to be about 17 000 eggs, calculated as the total number of discernible oocytes in the ovary and oviduct. Squid
were observed to spawn up to 8140 eggs over a 36 h period in captivity. First estimations of actual fecundity are therefore
between 8000 and 17 000 eggs. Factors complicating a more accurate estimation of actual fecundity in this species include
difficulties with aquarium maintenance, their behaviour of spawning over a protracted period and in multiple sites, and atretic
oocytes observed in both developing and mature ovaries. Detailed morphological and histological analysis of gonads collected
at regular intervals over a complete spawning season will allow a more precise calculation of actual fecundity.
Received: 9 October 1998 / Accepted: 22 April 1999 相似文献