Application of aquariological techniques to an intensive fish-rearing process using recycled, warmed water for the production of rainbow trout fry, Oncorhynchus mykiss     

P. Fontaine  D. Terver  A. Georges 《Aquacultural Engineering》1996,15(6):485-498

Since 1991, the Laboratoire de Biologie Appliquée has been developing a new, intensive fish-rearing process. Based on simple aquariological techniques used at the Nancy Aquarium Tropical, the process involves recycled, warmed (18–20°C) water, and autonomous modular units both technically simple and small in size. Among its applications is the production of rainbow trout fry, Oncorhynchus mykiss. At present, from an initial batch of 100 000 eye-stage embryonated eggs, it allows 85 000 fry of 0·8-1 g to be produced in 60 days for a water consumption of less than 10 m³.  相似文献   

Temporal and spatial patterns of denitrification enzyme activity and nitrous oxide fluxes in three adjacent vegetated riparian buffer zones     

Karel?Dhondt  Pascal?BoeckxEmail author  Georges?Hofman  Oswald?Van?Cleemput 《Biology and Fertility of Soils》2004,40(4):243-251

The aim of this study was to investigate temporal and spatial patterns of denitrification enzyme activity (DEA) and nitrous oxide (N₂O) fluxes in three adjacent riparian sites (mixed vegetation, forest and grass). The highest DEA was found in the surface (0–30 cm) soil and varied between 0.7±0.1 mg N kg^–1 day^–1 at 5°C and 5.9±0.4 mg N kg^–1 day^–1 at 15°C. There was no significant difference (P >0.05) between the DEA in the uppermost (0–30 cm and 60–90 cm) soil depths under different vegetation covers. In the two deepest (120–150 cm and 180–210 cm) soil depths the DEA varied between 0.0±0.0 mg N kg^–1 day^–1 at 5°C and 4.4±0.9 mg N kg^–1 day^–1 at 15°C and was clearly associated with the accumulation of buried organic carbon (OC). Two threshold values of OC were observed before DEA started to increase significantly, namely 5 and 25 g OC kg^–1 soil at 10–15°C and 5°C, respectively. In the three riparian sites N₂O fluxes varied between a net N₂O uptake of –0.6±0.4 mg N₂O-N m^–2 day^–1 and a net N₂O emission of 2.5±0.3 mg N₂O-N m^–2 day^–1. The observed N₂O emission did not lead to an important pollution swapping (from water pollution to greenhouse gas emission). Especially in the mixed vegetation and forest riparian site highest N₂O fluxes were observed upslope of the riparian site. The N₂O fluxes showed no clear temporal trend.  相似文献   

Genetic analysis of broad spectrum resistance to potyviruses using doubled haploid lines of pepper (Capsicum annuum L.)   总被引：4，自引：0，他引：4  

Catherine Dogimont  Alain Palloix  Anne-Marie Daubze  Georges Marchoux  Kashay Gebre Selassie  E. Pochard 《Euphytica》1996,88(3):231-239

Summary Genetic analysis of resistance to PVY in androgenetic doubled haploid lines, F1, F2 and backcross progenies of the Mexican pepper line, CM 334 (Capsicum annuum L.), was performed. Three reaction types were observed when seedlings were inoculated with several PVY strains of different pathotypes and with an American PeMV strain. Resistant genotypes never showed systemic symptoms although some individuals sporadically developed necrotic local lesions on inoculated cotyledons. Susceptible genotypes exhibited either a typical systemic mosaic or a systemic necrosis that caused the death of the inoculated seedlings. Segregation analyses indicated that resistance to pepper potyviruses in CM 334 is conferred by two genes. The first one, tentatively named Pr4, is dominant and confers the resistance to all now known pathotypes of PVY and to PeMV. The second one, tentatively named pr5, is recessive; it confers only the resistance to common strains of PVY. The systemic necrotic response is conferred by an independent dominant gene, tentatively named Pn1.  相似文献   

Bovine viral diarrhea (BVD) eradication in Switzerland--experiences of the first two years     

Presi P  Struchen R  Knight-Jones T  Scholl S  Heim D 《Preventive veterinary medicine》2011,99(2-4):112-121

A national eradication programme was designed with the aim of achieving total freedom from bovine viral diarrhea virus (BVDV) infection in the Swiss cattle population. The eradication programme consisted of testing every Swiss bovine for antigen, culling virus-positive animals and applying movement restrictions. Starting in 2008, the campaign achieved the goal of reducing the proportion of newborn calves that were virus-positive from 1.8% to under 0.2% within two years (situation in September 2010). Both good data flow between the parties involved as well as speed and efficiency (e.g. concerning the application of tests, movement restrictions and slaughter) are central to the success of the programme. Since the beginning of the programme 2.85 million cattle have been tested for bovine viral diarrhea virus (BVDV). The BVD-prevalence in cattle at the individual and herd levels following the implementation of the eradication programme was assessed. Using data collected during this campaign a risk factor analysis was conducted in order to identify factors associated with the appearance of virus positive newborn calves in herds where BVD had not previously been detected; these risk factors would allow targeting of future surveillance. Herd size, early death rate (i.e. the number of animals that either die before 15 days of age or are stillborn per number of newborns per year), buying in stock, using communal summer grazing, production type, age structure and management strategy were factors associated with the appearance of new cases of infection. Testing of newborn calves for antigen will continue to be conducted until the end of 2011, this is combined with outbreak investigation of newly infected herds (consisting of re-testing dams of virus-positive calves and if necessary all cattle on or that recently left the farm). This process is done to identify infected animals that may have been missed during prior testing (false negatives), it also serves to identify other factors that may be responsible for the introduction of BVDV onto the farm. Since October 2009, testing of calves for antigen combined with outbreak investigation has led to the detection of 55 infected animals that had tested negative (presumably false negative) during previous rounds of testing.  相似文献   

Furan formation from lipids in starch-based model systems, as influenced by interactions with antioxidants and proteins     

Owczarek-Fendor A  De Meulenaer B  Scholl G  Adams A  Van Lancker F  Eppe G  De Pauw E  Scippo ML  De Kimpe N 《Journal of agricultural and food chemistry》2011,59(6):2368-2376

The formation of furan upon sterilization of a lipid-containing starch gel was investigated in the presence of various antioxidants, namely, α-tocopherol, β-carotene, and ascorbic acid, with and without proteins. Results indicated that α-tocopherol did not significantly influence furan formation from oxidized lipids. β-Carotene, suggested previously to be a furan precursor itself, did influence the generation of furan in a concentration-dependent manner, although to a limited extent. Surprisingly, the presence of lipids seemed to limit the furan generation from β-carotene. Interestingly, the addition of ascorbic acid to the emulsions containing soybean or sunflower oils considerably enhanced the formation of furan from these oils. This was also the case when fresh oils were applied, shown previously to be nearly unable to generate furan. This observation can be explained by an intensified ascorbic acid degradation stimulated by the presence of lipids.  相似文献   

Temporal dynamics of soil hydraulic properties and the water-conducting porosity under different tillage   总被引：1，自引：0，他引：1  

Andreas Schwen  Gernot Bodner  Peter Scholl  Graeme D. Buchan  Willibald Loiskandl   《Soil & Tillage Research》2011,113(2):89-98

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Non-experimental validation of ethnoveterinary plants and indigenous knowledge used for backyard pigs and chickens in Trinidad and Tobago     

Lans C  Georges K  Brown G 《Tropical animal health and production》2007,39(5):375-385

This paper presents the findings of an exploratory study on ethnoveterinary medicines used for backyard pigs and backyard chickens in Trinidad and Tobago. Research data was collected from 1995 to September 2000. Six plants are used for backyard pigs. Crushed leaves of immortelle (Erythrina pallida, E. micropteryx) are used to remove dead piglets from the uterus. Leaf decoctions of bois canôt (Cecropia peltata) and bamboo (Bambusa vulgaris) are used for labour pains or leaves are fed as a postpartum cleanser. Boiled green papaya fruit (Carica papaya) is fed to pigs to induce milk let-down. The leaves and flowers of male papaya plants (Carica papaya) are fed to de-worm pigs. Sour orange juice (Citrus aurantium) is given to pigs to produce lean meat, and coffee grounds are used for scours. Eyebright and plantain leaves (Plantago major) are used for eye injuries of backyard chickens. Worm grass (Chenopodium ambrosioides) and cotton bush (Gossypium species) are used as anthelmintics. Aloe gel (Aloe vera) is used for internal injuries and the yellow sap from the cut Aloe vera leaf or the juice of Citrus limonia is used to purge the birds. A literature review revealed few toxicity concerns and the potential usefulness of the plants.  相似文献   

Observation of antiferromagnetic domains in epitaxial thin films     

Scholl A  Stohr J  Luning J  Seo JW  Fompeyrine J  Siegwart H  Locquet J  Nolting F  Anders S  Fullerton EE  Scheinfein MR  Padmore HA 《Science (New York, N.Y.)》2000,287(5455):1014-1016

Antiferromagnetic domains in an epitaxial thin film, LaFeO(3) on SrTiO(3)(100), were observed using a high-spatial-resolution photoelectron emission microscope with contrast generated by the large x-ray magnetic linear dichroism effect at the multiplet-split L edge of Fe. The antiferromagnetic domains are linked to 90 degrees twinned crystallographic regions in the film. The Neel temperature of the thin film is reduced by 70 kelvin relative to the bulk material, and this reduction is attributed to epitaxial strain. These studies open the door for a microscopic understanding of the magnetic coupling across antiferromagnetic-ferromagnetic interfaces.  相似文献   

Comment on "How science survived: medieval manuscripts' 'demography' and classic texts' extinction"     

Declercq G 《Science (New York, N.Y.)》2005,310(5754):1618; author reply 1618

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Influence of variety,date of harvest and storage time on factors connected with the crystallisation on canned scorzonera (Scorzonera hispanica)     

Georges Vulsteke  André Calus 《Plant foods for human nutrition (Dordrecht, Netherlands)》1990,40(2):149-166

In the period 1983–1986, research was carried out into the inulin content of scorzonera during ripening and storage. Since the inulin content is determining for the occurrence of crystallisation with canned scorzonera, the effects of the varieties, the time of harvest and storage of the scorzonera were investigated.The changing of the inulin content on the conversion into reducing sugars was checked; the effect of the dry matter and nitrate content were also defined.The aim was to define whether the determination of the inulin content was a useful parameter for the ripening of the scorzonera. On the whole, the different varieties showed remarkable difference where fructosanes+inulin, as well as pure inulin, were concerned.A significant decrease of the inulin content was obtained from the middle of November, by so far that it was below the limit above which crystallisation takes place.A two-month storage period of scorzonera harvested in early October also led to a very low inulin content, so that no problems could occur while canning. Storage conditions of the scorzonera seemed of importance too.The nitrate content of the different scorzonera varieties was low, although some variations were noted. The crops harvested in early December showed considerably lower contents when compared to those harvested in early October or mid-November.The inulin content as well as the content of reducing sugars are a useful parameter to determine the maturity of the scorzonera.This research was subsidized by the Instituut tot Aanmoediging van het Wetenschappelijk Onderzoek in Nijverheid en Landbouw (I.W.O.N.L.).  相似文献