Keys to the adult male Chironomidae of Britain and Ireland     

Gerard van der Velde 《Aquaculture Research》2007,38(15):1692-1692

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Energy balance of Litopenaeus vannamei postlarvae fed on animal or vegetable protein based compounded feeds     

Luis Jimnez-Yan  Abelardo Brito  Gerard Cuzon  Gabriela Gaxiola  Toms García  Gabriel Taboada  Luis A. Soto  Roberto Brito 《Aquaculture (Amsterdam, Netherlands)》2006,260(1-4):337-345

L. vannamei postlarvae are normally raised with a protein dense diet (50% protein) rich in fishmeal. Part of the protein is utilized for energy purpose instead of protein synthesis. Based on a previous energy partitioning study, the effects of two isoenergetic compounded feed treatments – animal protein (AP) and vegetable protein and carbohydrates (VPC) – upon growth efficiency and energy budget of shrimp postlarvae and early juveniles were determined. Recovered energy (RE) or production (P) after 50 days trial was similar (2 J day^− 1) in both treatments, from PL₁₄ to PL₁₉. However, early juveniles discriminated between animal protein (116 J day^− 1) and vegetable protein and carbohydrates (88 J day^− 1). The difference in respiration indicated a higher heat increment with AP compared to VPC. At maintenance level, energy used was lower with AP than VPC treatment. Postlarvae and early juveniles employed protein as a main energy substrate (O:N < 20). Differences in the efficiencies observed in the calculated energy budget were attributed to the presence of carbohydrates in diet and not to the protein source. The advantage of incorporating vegetable protein source in the diet of harvesting shrimp may eventually contribute towards a reduction of fishmeal costs and waste products as well as to achieve sustainable shrimp farming.  相似文献   

Changing patterns in insect pests on trees in The Netherlands since 1946 in relation to human induced habitat changes and climate factors—An analysis of historical data     

Leen G. Moraal  Gerard A.J.M. Jagers op Akkerhuis 《Forest Ecology and Management》2011,261(1):50-61

In The Netherlands, insect pests on trees and shrubs are being monitored continuously since 1946. During these years, almost all insect pest populations showed marked changes, which may be the result of changes in forest management, shifts in forest composition, climate change and the arrival of new pests from the Mediterranean region or from other continents. In order to generate hypothesis about possible relationships between species ecology and environmental factors, we have analyzed 61 years of population development of the 98 most abundant species in the database while paying attention to life history traits and preferred host plants. The 22 species with infestations lasting a few years only were excluded from the analysis. Of the remaining 76 species, 18 were present over the entire observation period of 61 years. Of the other species, 27 showed a decline and 31 showed an increase. On coniferous trees most species showed decreasing populations. Increasing populations were found most on deciduous trees. Not directly climate-related factors such as changes in forest age, tree composition and forest management were identified as the most important causes for the fluctuations in pest insect populations. Climate change is a possible driver of the population increase in Thaumetopoea processionea, Haematoloma dorsatum and of the population decrease in Euproctis chrysorrhoea. The recently increasing exotic species Eupulvinaria hydrangeae and Pulvinaria regalis were exclusively found on trees in cities, presumably in relation to the higher temperatures of the urban habitat.  相似文献   

The conservation effects of meadow bird agreements on farmland in Zeeland, The Netherlands, in the period 1989-1995     

David Kleijn  Gerard J.C van Zuijlen 《Biological conservation》2004,117(4):443-451

Meadow bird agreements are the most important Dutch agri-environment schemes, both in terms of uptake and of aim. Meadow bird agreements postpone the first agricultural activities on grassland thus reducing egg and chick mortality due to mowing or grazing. We investigated the conservation effects of meadow bird agreements by analysing settlement densities of meadow birds on 34 fields in 1989, 1992 and 1995 in the province of Zeeland, The Netherlands. We compared territory numbers on fields with meadow bird agreements with paired nearby control fields that were conventionally managed. In 1995, the number of territories of black-tailed godwit (Limosa limosa), lapwing (Vanellus vanellus) and the total number of meadow birds were significantly higher on fields with conservation management. These differences were partly caused by the higher quality (i.e. higher groundwater level) of fields with meadow bird agreements. Population trends were similar on fields with and without meadow bird agreements and the observed difference in settlement density in 1995 was already present in 1989. Furthermore the effectiveness of the scheme did not increase with time. Thus we found no conclusive evidence that the conservation measures themselves did result in higher territory numbers. Currently, we do not have sufficient ecological and behavioural knowledge of meadow birds to explain why the higher reproductive success does not result in higher settlement densities.  相似文献   

Deposition and depletion of five anticoccidials in eggs     

Mortier L  Huet AC  Daeseleire E  Huyghebaert G  Fodey T  Elliott C  Delahaut P  Van Peteghem C 《Journal of agricultural and food chemistry》2005,53(18):7142-7149

Anticoccidials are compounds that are widely used as feed additives to prevent and treat coccidiosis. They are licensed for use in a prescribed concentration and during a certain time interval for broilers and pullets but not for laying hens. It was shown in the past that carry-over at the feeding mill is found to be the main reason for the presence of residues in eggs. An animal experiment was set up to investigate the effect of carry-over at the feeding mill on the presence of residues of anticoccidials in eggs. For the compounds diclazuril, robenidine, halofuginone and nicarbazin in combination with narasin, two concentration levels were tested: the maximum allowed concentration for broilers (100%) and a concentration corresponding to 5% carry-over during feed preparation. Also dimetridazole was included in the experiment but only at one concentration level. Eggs were sampled during treatment (14 days) and for a period of 30 days after withdrawal of the anticoccidial-containing feed. Residues were determined, and deposition and depletion curves were generated. Analyses were performed by ELISA and LC-MS/MS. For all compounds, substantial residues could be found in the 5% groups, which points out the risk of carry-over at the feeding mill. The distribution of the residues between egg yolk and white was determined by analyzing both fractions.  相似文献   

Monitoring Metal Speciation in The rivers Meuse and Rhine Using DGT     

Rob Cleven  Yusuf Nur  Petra Krystek  Gerard Van Den Berg 《Water, air, and soil pollution》2005,165(1-4):249-263

Although a number of metal speciation methods are nowadays available, most water quality regulations are based on total metal concentrations. One of the main reasons for the ignorance of speciation is the lack of methods with potentiality for monitoring. Conditions that have to be met by such speciation methods are: simple performance, robust and sufficiently accurate. In this study the potential for monitoring purposes of Diffusive Gradients in Thin films (DGT) is investigated as part of a European project for sensor development for routine prediction of metal biouptake in natural waters. Performance characteristics of DGT have been assessed in experiments under controlled laboratory conditions and during in situ application over 4–9 months under different hydrological conditions in the rivers Meuse and Rhine. Results have been worked out for Cu, Ni and Pb. The study shows that DGT has sufficient potential as a robust tool in routine monitoring to observe trends in water quality. However, it appears that during in situ application of DGT the measurement uncertainty of the results is much larger than under laboratory conditions. The increase in measurement uncertainties will partially be due to uncertainties in some as constant considered factors in the calculation of the DGT concentration. For Cu and Ni, the average values for the reproducibility in the rivers Meuse and Rhine appeared to be 28% and 17%, respectively, whereas under laboratory conditions the reproducibilities for both metals were better than 10%. In the speciation of Cu, Ni and Pb in the rivers Meuse and Rhine, the labile fraction, determined using DGT, decreased in the series Ni, Cu, Pb. The ratio of the non-labile and labile fractions of the metals appeared to decrease with increasing content of Dissolved Organic Carbon (DOC).  相似文献   

Phenolic diterpenes,flavones, and rosmarinic acid distribution during the development of leaves,flowers, stems,and roots of Rosmarinus officinalis. Antioxidant activity     

del Baño MJ  Lorente J  Castillo J  Benavente-García O  del Río JA  Ortuño A  Quirin KW  Gerard D 《Journal of agricultural and food chemistry》2003,51(15):4247-4253

The distribution of six compounds with three different polyphenol skeletons have been studied in Rosmarinus officinalis: phenolic diterpenes (carnosic acid, carnosol, and 12-O-methylcarnosic acid), caffeoyl derivatives (rosmarinic acid), and flavones (isoscutellarein 7-O-glucoside and genkwanin), each showing a characteristic behavior and distribution during the vegetative cycle. Only in leaves were all six compounds present, and the highest accumulation rate was related with the young stages of development. Rosmarinic acid showed the highest concentrations of all the polyphenols in all organs. The distribution of this acid in leaves, flowers, and stems suggests that in the first stages of flower growth, levels were due to in situ biosynthesis, and in the last stages, the contribution of transport phenomena was increased. The antioxidant activity of six extracts with different polyphenolic composition was evaluated in aqueous and lipid systems. The results clearly suggest that rosemary extracts are excellent antioxidants in both aqueous and lipid systems.  相似文献   

West Nile Virus on the rise: alertness recommended     

van Maanen K  Reusken C  Martin B  Sonder G  van Gorp E  Koopmans M 《Tijdschrift voor diergeneeskunde》2011,136(7):518-520

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Steroid-responsive meningitis-arteritis with spontaneous echocardiographic contrast and elevated cardiac troponin I in a dog     

Navarro-Cubas J  Bell R  Wotton PR  Gutierrez-Quintana R  McLauchlan G 《The Veterinary record》2011,169(20):527

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Corrigendum to “Automated observation and analysis of earthworm surface behaviour under experimental habitat quality and availability conditions” [Pedobiologia – International Journal of Soil Biology (53/4) 259–263]     

Jan Valckx  Annabel Pennings  Toon Leroy  Daniël Berckmans  Gerard Govers  Martin Hermy  Bart Muys 《Pedobiologia》2011,54(1):53-55

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