Sediments in the Catchment-coast Continuum (7 pp)     

Wim Salomons 《Journal of Soils and Sediments》2005,5(1):2-8

-  Dedicated to Prof. Dr. Ulrich Förstner on his 65th birthdayBackground   Sediments pose problems at their deposition sites when there is too little sediment (e.g. wetlands) or too much sediment (e.g. navigable waterways) and, additionally, when they are contaminated. These problems often have their origin upstream in the river catchment. Objective   Global aspects of changes concerning sediment quantity and quality, as they affect downstream areas, are reviewed. A case study of estuarine sediments demonstrates how a holistic approach helps in understanding and predicting their present and future quality. Results and Conclusions   Globally, large reservoirs intercept between 25 and 30% of the sediment and consequently supply the coast with impacts on wetlands and coastal morphology. In estuaries, the composition of sediments is determined by the mixing of marine sediments supplied from the coast and the supply by rivers. Natural tracers can be used to predict mixing ratios of marine to fluvial sediments in estuaries, and hence their contamination. Scenarios on implementation of pollution abatement, the implementation of regulations as well as climate change are needed to predict future sediment quality in downstream areas. The results show, even for a ‘green’ scenario, that sediment quality in the Rhine catchment will pose future problems due to the temporal storage of contaminants in soils and sediments.Recommendations and Outlook   The current methods applied make use of existing models linking sediment transport with point and diffuse sources in the river catchments and scenarios on the development of strength of point and diffuse sources. However, more effort is needed to come to a uniform framework which includes land use changes and links with more advanced scenario methodology for long to medium-term management of sediment quality and quantity in river catchments.  相似文献   

Comparison of measured and simulated changes in base cation amounts using a one-layer and a multi-layer soil acidification model     

Harmke Van Oene  Wim De Vries 《Water, air, and soil pollution》1994,72(1-4):41-65

Biogeochemical processes describing nutrient cycling strongly affect the development of different soil horizons and soil acidification. However, in many soil acidification models these processes are not directly simulated, and spatially distributed soil properties are lumped into average values. This paper describes the extension of a one-layer soil acidification model (SMART) to a multi-layer model (SMARTEX) by including nutrient cycling, and the performance of both models regarding their ability for the assessment of the effects of acid deposition on forest soil. This was done by comparing simulation results of the two models with respect to changes in base cation amounts to historical data from sites in south Sweden. The results showed that the multi-layer model gives better results for the top soil, whereas the one-layer model gives better results for the rootzone and the total profile. Since the top soil is most important, the extended model is more suited to relate acid deposition to forest growth than the more general results of the one-layer model. However, the sensitivity of the multi-layer model to some parameters is large. A change in these parameters had strong effects on the separate layers, whereas the effects were cancelled out over the total profile. This sensitivity requires a careful parameterization of the model which might be troublesome to lack of data.  相似文献   

A regional scale model for the calculation of episodic concentrations and depositions of acidifying components     

H. Jetske van Rheineck Leyssius  Frank A. A. M. de Leeuw  Bert H. Kesseboom 《Water, air, and soil pollution》1990,51(3-4):327-344

An eulerian long-range transport model for the calculation of concentrations of SO₂, SO₄, NO _x , and NO₃ and wet and dry depositions of SO _x (sum of SO₂ and SO₄) and NO _y (sum of NO, NO₂ and NO₃) over Europe is presented. The model is developed in such a way that only routinely available, analyzed or prognostic meteorological fields are required as input data. In this way it is possible to obtain a forecast of the air quality during smog episodes. For evaluation of smog episodes the model provides a way to estimate the contributions of different sources and the effect of emission scenarios. The model has been evaluated for four winter and three summer episodes. The modeled concentrations of SO₂ and SO, are in agreement with the available measurements. A less good agreement is found for NO₂ and NO _x (sum of NO and NO₂) concentrations. For these components the model tends to underpredict the measured values.  相似文献   

Gynogen Production in Hybrid Striped Bass     

Gilles M.  Leclerc  Bert  Ely  Xiao Lan  Xu Reginal M.  Harrell 《Journal of the World Aquaculture Society》1996,27(1):119-124

Abstract.— Meiotic gynogens were produced using hybrid striped bass (♀ white bass, Morone chrysops , ×♂ striped bass, M. saxatilis ) eggs and white perch M. americana UV-irradiated sperm. Diploidy of the fertilized eggs was restored by application of hydrostatic pressure, which induced retention of the second polar body. Use of white perch sperm provided an unmistakable marker for detection of a paternal genetic contribution. Two assays were developed using the polymerase chain reaction (PCR) to amplify specific regions of the Morone genome . Primers for gene amplification were developed based on the DNA sequence of the striped bass growth hormone gene (SB-GH) or an anonymous striped bass locus (SBI-10). Control experiments using DNA from the three Morone species demonstrated that gene amplification yielded species-specific patterns of DNA fragments for both of these loci. Therefore, any progeny with a paternal contribution of a set of white perch chromosomes could be identified. Using these assays, we demonstrated that greater than 75% of the progeny obtained from successful experiments were true gynogens. These striped bass hybrid gynogens will provide the basis for future efforts to calculate gene-centromere distances and to identify markers linked to specific traits of interest to aquaculture.  相似文献   

Legal regulations and practical application of studies of slaughtered game animals and their meat     

R M Hadlok  F Bert 《Tier?rztliche Praxis》1989,17(4):347-351

Meat regulations also involve game inspection. The previous publications on the one hand dealt with the regulations and their practice concerning game intended for slaughter, especially the control of fences and the gaining of meat. On the other hand regulations concerning game hunted for food (Deer: Red deer, Sika deer, Fallow deer, Roe deer; Horned ungulates: European mouflon, Chamois; Wild boar; European hare; European rabbit; game such as Badger and Raccoon) and regulations to be observed by hunters, mainly for the gaining of meat were discussed. The recent publication regarded meat inspection (routine inspection) of slaughter game. The following publication deals with meat inspection (routine inspection) of game hunted for food and with meat inspection (additional inspection) of slaughtered game as well as game hunted for food.  相似文献   

Experimental data on the pathogenesis of edema disease of swine. Clinical picture, gross and microscopic lesions related to endotoxin shock   总被引：2，自引：0，他引：2  

Z Nagy  I Berczi  L Bertók 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1968,15(4):504-511

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Superficial keratectomy and cryosurgery as therapy for limbal neoplasms in 13 horses   总被引：1，自引：1，他引：0  

Bosch G  Klein WR 《Veterinary ophthalmology》2005,8(4):241-246

Objective To determine the usefulness and clinical outcome of a combined procedure of superficial keratectomy and cryosurgery as a treatment for limbal neoplasms in horses. Study design Retrospective study. Animals Thirteen horses with 14 limbal tumors. Methods Medical records of all patients with limbal tumors, referred to the Department of Equine Sciences of Utrecht University between 1995 and 2002, were retrieved. Patient data were analyzed with respect to signalment, tumor surface area and histologic diagnosis. Surgery, performed under general anesthesia, included surgical debulking of the tumor followed by cryosurgery. Long‐term follow‐up information was obtained by re‐evaluation in the clinic, by the referring veterinarian, and/or by telephone enquiry. Results Therapy was successful in 9 out of 14 eyes after the first attempt (64%); one eye needed retreatment (7%), and four eyes were eventually enucleated (29%). The mean follow‐up period was 4.8 years. The initial surface area of the tumor significantly influenced outcome (P < 0.01). Squamous cell carcinoma was the most predominant tumor type (79%). Haflinger horses accounted for 69% of the cases whereas their occurrence in the overall hospital population is approximately 5%. Conclusions and clinical relevance The described technique of superficial keratectomy and cryosurgery is a simple procedure for the treatment of limbal tumors in equine patients that does not require sophisticated equipment. Nor is it tampered by legal restriction, and appears to be effective in tumors with a small surface area (< 2 cm²). Haflinger horses seem to be predisposed for the development of ocular squamous cell carcinoma.  相似文献   

Letter to the members of the Dutch Veterinary Medicine Societies Update new quality control management     

van den Ekker W  den Hertog A  Gostelie E  Verburgh M  Bouwhuis G  Hooijer GA  van Dongen F  Urlings B  van Mameren J  Hof M  Mandigers P 《Tijdschrift voor diergeneeskunde》2005,130(13):428-429

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Clomipramine and selegiline: do they influence impulse control?     

Bert B  Harms S  Langen B  Fink H 《Journal of veterinary pharmacology and therapeutics》2006,29(1):41-47

Anxiety disorders in dogs are often accompanied by loss of impulse control and can result in inappropriate behaviour such as destructiveness, excessive barking and aggression. The reduction of these undesirable actions is the focus of behaviour therapy. Clomipramine and selegiline have been approved for the treatment of separation anxiety in dogs, but there are anecdotal reports that they produce inconsistent therapeutic effect. Hence, the aim of this study was to verify the efficacy of clomipramine and selegiline for regulating impulse control by using a rat model based on the delay of reward procedure. The principle is that the animal has to decide between an immediate small food reward, normally preferred by impulsive animals, and a delayed large food reward. In this study, acute effects of clomipramine (0.3-10.0 mg/kg), selegiline (0.3-3.0 mg/kg), and diazepam (1.0-3.0 mg/kg) on the impulsive behaviour of two breeding lines of rats with different anxiety-related behaviour were investigated. Neither clomipramine nor selegiline had an effect on impulse control in either breeding line. However, motor activity was decreased by clomipramine and increased by selegiline. Diazepam led to an increase in impulsive behaviour of one rat line concomitant with an increase in motor activity. The results of this rat model for studying impulsive behaviour suggest that a single administration of selegiline and clomipramine has no influence on impulsive behaviour.  相似文献   

A bacterial protein enhances the release and efficacy of liposomal cancer drugs     

Cheong I  Huang X  Bettegowda C  Diaz LA  Kinzler KW  Zhou S  Vogelstein B 《Science (New York, N.Y.)》2006,314(5803):1308-1311

Clostridium novyi-NT is an anaerobic bacterium that can infect hypoxic regions within experimental tumors. Because C. novyi-NT lyses red blood cells, we hypothesized that its membrane-disrupting properties could be exploited to enhance the release of liposome-encapsulated drugs within tumors. Here, we show that treatment of mice bearing large, established tumors with C. novyi-NT plus a single dose of liposomal doxorubicin often led to eradication of the tumors. The bacterial factor responsible for the enhanced drug release was identified as a previously unrecognized protein termed liposomase. This protein could potentially be incorporated into diverse experimental approaches for the specific delivery of chemotherapeutic agents to tumors.  相似文献