Beach nourishment: an ecologically sound coastal defence alternative? A review     

Jeroen Speybroeck  Dries Bonte  Wouter Courtens  Tom Gheskiere  Patrick Grootaert  Jean‐Pierre Maelfait  Mieke Mathys  Sam Provoost  Koen Sabbe  Eric W.M. Stienen  Vera Van Lancker  Magda Vincx  Steven Degraer 《水产资源保护:海洋与淡水生态系统》2006,16(4):419-435

• 1. Even though beach nourishment is generally considered as an environment‐friendly option for coastal protection and beach restoration, sizeable impacts on several beach ecosystem components (microphytobenthos, vascular plants, terrestrial arthropods, marine zoobenthos and avifauna) are described in the literature, as reviewed in this paper.
• 2. Negative, ecosystem‐component specific effects of beach nourishment dominate in the short to medium term, with the size of the impact being determined by (1) activities during the construction phase, (2) the quality and (3) the quantity of the nourishment sand, (4) the timing, place and size of project, and (5) the nourishment technique and strategy applied. Over the long term the speed and degree of ecological recovery largely depend on the physical characteristics of the beach habitat, mainly determined by (1) sediment quality and quantity, (2) the nourishment technique and strategy applied, (3) the place and the size of nourishment and (4) the physical environment prior to nourishment.
• 3. The limited information available on indirect and cumulative ecological effects indicates that these effects cannot be neglected in an overall impact assessment. Hence, for ecologically good practice of beach nourishment it is advised (1) to choose nourishment sands with a sediment composition comparable to that of the natural sediment, (2) to avoid short‐term compaction by ploughing immediately after construction, (3) to execute the nourishment in a period of low beach use by birds and other mobile organisms, (4) to choose a number of smaller projects rather than a single large nourishment project and (5) to select the nourishment technique with respect to the local natural values.
• 4. In order to allow an objective, scientifically sound, ecological adjustment of future nourishments, research should aim at (1) taking into account the full sandy beach ecosystem, (2) avoiding strategic imperfections in experimental design and (3) elucidating the biological processes behind impact and recovery of all ecosystem components.

Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Introducing undeinked old newsprint as a new resource of electrical purposes paper     

Tamer Y. A. Fahmy  Fardous Mobarak  Magda G. El-Meligy 《Wood Science and Technology》2008,42(8):691-698

This work introduces, for the first time worldwide, undeinked recycled old newsprint as a new resource of electrical purposes paper. Impregnation of undeinked recycled old newsprint paper with linseed oil enhances the breaking length of paper and remarkably improves its electrical properties, i.e., the dielectric constant increases greatly and the a.c. conductivity decreases significantly due to impregnation. It was found that the electrical properties of the undeinked old newsprint paper and its linseed oil impregnated counterpart are close to the electrical properties of paper made from the more expensive virgin wood pulps and their linseed oil impregnated counterparts. Using the undeinked pulp is more privileged than using the deinked pulp; because eliminating the deinking step saves money, time, and reagents. In addition, eliminating the deinking step improved the breaking length of paper. Electron dispersive X-ray elemental analysis (EDX) was used to investigate the undeinked and deinked pulps for residual elements originating from the printing materials. EDX was correlated to the slight differences in electrical properties of paper made from undeinked and deinked pulps. However, impregnation was able to overcome these slight differences. It was shown that improvement in electrical properties, due to impregnation, is sustained at elevated temperatures.  相似文献   

Molecular characterization of the VP1 gene of a Mexican isolate of infectious pancreatic necrosis virus     

Barrera-Mejía M  Simón-Martínez J  Ulloa-Arvizu R  Salgado-Miranda C  Soriano-Vargas E 《Canadian journal of veterinary research》2010,74(3):218-222

The presence of infectious pancreatic necrosis virus (IPNV) in salmonids predominantly produces a high mortality rate in first-feeding fry. Genomic analysis of the vp2 gene sequence is most commonly used to determine the genetic diversity of IPNV isolates. Recently, information obtained from the vp1 gene allowed for efficient analysis of the genetic diversity of IPNV. In this study, the vp1 gene from a Mexican IPNV isolate was characterized and compared with IPNV isolates from Europe, North America, and Asia. The results indicate that the Mexican isolate is most closely related genetically to the 2310 strain from Spain.  相似文献   

Evaluation of the effects of footwear hygiene protocols on nonspecific bacterial contamination of floor surfaces in an equine hospital     

Stockton KA  Morley PS  Hyatt DR  Burgess BA  Patterson G  Dunowska M  Lee DE 《Journal of the American Veterinary Medical Association》2006,228(7):1068-1073

OBJECTIVE: To evaluate the effects of footwear hygiene protocols on bacterial contamination of floor surfaces in an equine hospital. DESIGN: Field trial. PROCEDURES: Footwear hygiene protocols evaluated included use of rubber overboots with footbaths and footmats containing a quaternary ammonium disinfectant, rubber overboots with footbaths and footmats containing a peroxygen disinfectant, and no restrictions on footwear type but mandatory use of footbaths and footmats containing a peroxygen disinfectant. Nonspecific aerobic bacterial counts were determined via 2 procedures for sample collection and bacterial enumeration (contact plates vs swabbing combined with use of spread plates), and the effects of each footwear hygiene protocol were compared. RESULTS: There were no consistent findings suggesting that any of the protocols were associated with differences in numbers of bacteria recovered from floor surfaces. Although there were detectable differences in numbers of bacteria recovered in association with different footwear hygiene protocols, differences in least square mean bacterial counts did not appear to be clinically relevant (ie, were < 1 log10). CONCLUSIONS AND CLINICAL RELEVANCE: Although cleaning and disinfection of footwear are important aids in reducing the risk of nosocomial transmission of infectious agents in veterinary hospitals, the numbers of aerobic bacteria recovered from floor surfaces were not affected by use of rubber overboots or the types of disinfectant used in this study. Further study is warranted to evaluate the usefulness of footwear hygiene practices relative to their efficacy for reducing transmission of specific pathogens or decreasing nosocomial disease risk.  相似文献   

Consequences of less intensive farming on the landscape: an example of vegetation dominance by Chaerophyllum aureum in the meadows of a Pyrenean valley in France     

Danièle Magda  Jean-François Gonnet 《Landscape Ecology》2001,16(6):491-500

The impact of agricultural practices on the dynamics of weed invasion in a rural landscape was studied by describing the spatial distribution of Chaerophyllum aureum populations colonising less intensive managed hay meadows. Polyphenol compounds were used as individual markers to identify the structure of C. aureum diversity, in terms of its scale and patterns, within and between fields along the bottom of a Pyrenean valley. The results revealed, firstly, the existence of a dominant `genotype' successfully colonising the entire area, and secondly, the maintenance of high levels of polyphenol diversity within five different populations. This spatial arrangement of `genetic' population diversity was obviously not related to the natural reproduction and dispersal patterns of this species, but to human practices of hay production, the principal effect of which is to mix seeds of different genetic origin and thus accelerate and amplify the colonisation process of adapted `genotypes'.  相似文献   

Can sodium regulation be used to predict the relative acid-sensitivity of various life-stages and different species of aquatic fauna?     

Magda Havas  Eric Advokaat 《Water, air, and soil pollution》1995,85(2):865-870

Fishes, Zooplankton, insect larvae, and benthic invertebrates differ in their sensitivity to acidic waters. Some species are able to survive and complete their life-cycle below pH 3.5 while others are eliminated once the pH drops below 5.5. Generally, acid-sensitive fauna are highly water permeable and have difficulty regulating osmotically essential ions, such as sodium and chloride, at low pH. Increased permeability during certain stages of a life-cycle (post-molt crayfish, for example) are often associated with increased acid-sensitivity. Special adaptations, including enlarged anal papillae in Chironomids and the number and morphology of chloride cells in such diverse organisms as crustaceans, insect larvae, and fishes, may enhance acid-tolerance. To test the hypothesis that Na⁺ regulation can be used to predict relative acid-sensitivity of aquatic fauna we will need a mechanism for standardizing Na⁺ regulatory capability.  相似文献   

Vitamin B₆ supplementation increases the docosahexaenoic acid concentration of muscle lipids of rainbow trout (Oncorhynchus mykiss)     

Magda Maranesi  Mario Marchetti  Davide Bochicchio  & Luciana Cabrini 《Aquaculture Research》2005,36(5):431-438

Fish fillet quality is influenced by feed quality. In particular, vitamin B₆ availability improves growth rate and nutritional value, because it is related to protein and lipid metabolism. The present study investigates the effect of increasing amounts of vitamin B₆ on growth, fatty acid composition and lipid peroxidation of muscle tissue of rainbow trout (Oncorhynchus mykiss). Quadruplicate groups of trout of a mean initial weight of 110 g were fed commercial diets supplemented with four different quantities of vitamin B₆ (0, 10, 25 and 50 mg kg^?1 diet). Over the experimental period, there were no significant differences in weight gain and feed intake, while vitamin B₆ concentration of muscle was affected by dietary intake, even though its increase was not proportional to the concentrations in the feed. The fatty acid composition of muscle lipid showed differences between the four groups. The percentage of long‐chain unsaturated fatty acids, in particular docosahexaenoic acid, increased significantly in vitamin B₆‐supplemented groups. However, despite the increased fatty acid unsaturation index, lipid peroxidation parameters such as vitamin E content, malondialdehyde production, glutathione reductase and glutathione peroxidase activities did not show significant differences, meaning that the higher level of long‐chain unsaturated fatty acid did not increase the muscle susceptibility to oxidative stress.  相似文献   

Three new Chromadoropsis species (Nematoda,Desmodoridae) from Southern Africa and the North Sea     

J.P. Furstenberg  Magda Vincx 《African Zoology》2013,48(3):215-223

Three new Chromadoropsis species with four pharyngeal bulbi are described from Southern Africa, Namibia (S.W.A.) and the North Sea. C. granulosus sp.nov. is described from a sandy beach near Port Elizabeth. This species is characterized by a very distinct layer of yellow granules just below the cuticle. C. namibiensis sp.nov. is described from a sandy beach at Langstrand, Namibia. This species can be distinguished by the length and shape of the gubernaculum and spicules as well as the size of the capitulum. C. longispiculosa sp.nov. is described from the North Sea and is characterized by the long spicules and the presence of numerous porids. The genus Chromadoropsis Filipjev, 1918 is revised.  相似文献   

Effect of cultivar on the protection of cardiomyocytes from oxidative stress by essential oils and aqueous extracts of basil (Ocimum basilicum L.)     

Danesi F  Elementi S  Neri R  Maranesi M  D'Antuono LF  Bordoni A 《Journal of agricultural and food chemistry》2008,56(21):9911-9917

Notwithstanding the wide range of biological and pharmacological activities reported for sweet basil (Ocimum basilicum L.), many discrepancies are still present in the evaluation of its health-promoting properties. These discordances could be at least in part due to insufficient details of qualitative and quantitative composition, connected to the ample variability of this species. Furthermore, many investigations have been carried out in vitro, with few data available on the effectiveness in biological systems. In this study, the protective effect of essential oils and water-soluble extracts derived from three different cultivars of sweet basil has been evaluated in cultured cardiomyocytes. To verify the effectiveness of supplemented oils/extracts in counteracting oxidative damage, cardiomyocytes were stressed by the addition of hydrogen peroxide. The results indicate that (a) in vitro antioxidant activity is not predictive of biological activity and (b) basil can yield extracts with substantially different protective effects, in relation to composition and extraction techniques. Variation among different cultivars has also been detected.  相似文献   

Differential Bos taurus cattle response to Babesia bovis infection     

Benavides MV  Sacco AM 《Veterinary parasitology》2007,150(1-2):54-64

Bovine babesiosis is a tick-borne disease caused by Babesia spp. haemoprotozoans. The disease is of great importance at tick enzootic unstable areas and hampers cattle production in several developing countries. The available immunisation alternatives are pre-immunition and attenuated vaccines. Despite being efficient and protective, they are unsafe as they use cattle blood cells as inoculum and may potentially spread other diseases. Another alternative to help in babesiosis control would be the identification of genetically resistant cattle to Babesia bovis infection. The objective of this work was to phenotype cattle based on primary response against B. bovis infection. Two-hundred and forty half-sib Hereford and Aberdeen Angus heifers (120 animals from each breed), 12-18-month-old na?ve cattle, originated from a tick-free area in Southern Brazil, were used in the experiment. Animals were monitored following an inoculation with 1x10(7)B. bovis parasitised erythrocytes. Results showed three different phenotypes: 1-'susceptible', animals with babesiosis clinical signs that received treatment to avoid death; 2-'intermediate', animals with clinical signs: parasitaemia, >or=21.5% reduction in packed cell volume (PCV) and increase in body temperature when compared to their pre-challenge physiological parameters, no specific treatment was needed as animals self recovered from the disease, and 3-'resistant', animals without clinical signs that showed B. bovis presence in blood smears, <21.5% PCV reductions, with little or no increase in body temperature and no need for babesiosis treatment. The frequencies of each phenotype were: 45.4, 26.7, and 27.9%, respectively, demonstrating the existence of phenotypic variation for B. bovis in Bos taurus cattle.  相似文献