Judging Fitness for Purpose of a X-ray Fluorescence Based Method Investigating the Vertical Distribution of Metals and Metalloids in Soil Profiles     

Peter Morgenstern  Lutz Brüggemann  Frank Krüger  Anke Hofacker  Rainer Wennrich 《Water, air, and soil pollution》2008,193(1-4):289-298

A column of soil, excavated from a contaminated landscape was evaluated by means of X-ray fluorescence analysis. The measurements were intended to assess the vertical distribution of heavy metals and toxic elements in the depth profile. To judge fitness for purpose of the analytical method used the element specific power functions were derived yielding the minimum detectable variations of analyte concentrations refer to the investigated soil profile. The required measurement uncertainty components caused by both the sampling procedure and chemical analysis were empirically estimated using a nested sampling design (duplicate method). For this purpose the full length of the soil core was divided into horizontal layers. From each selected layer (sampling target) two composite samples were taken by simple random sampling to represent the typical composition of the sampling target. The pool of measurement results, obtained for the nested sampling design finally was subjected to variance analysis. The evaluation of the estimated variance components in terms of the percentage of total variance confirmed fitness for purpose for the method used.  相似文献   

A pilot survey of socio-economic differences in child-feeding behaviours among parents of primary-school children     

Clark HR  Goyder E  Bissell P  Blank L  Walters SJ  Peters J 《Public health nutrition》2008,11(10):1030-1036

OBJECTIVE: Parentss food choices and weight, but little is known about the social class distribution of parent self-reported child-feeding behaviours in two socio-economically contrasting areas. DESIGN: A cross-sectional survey using the Parental Feeding Style Questionnaire. Mean scores were calculated for five child-feeding behaviours: control over eating, emotional feeding, encouragement/prompting, instrumental feeding and restriction. Parents behaviours that might be used to directly influence children's food intake and weight. CONCLUSIONS: Child-feeding behaviours differ between areas within a single city and within a largely white population, and this distribution is related to socio-economic and educational factors. Experimental and longitudinal studies are needed to further investigate the potential role of child-feeding behaviours in childhood overweight and obesity.  相似文献   

Effects of humus content,farmyard manuring,and mineral‐N fertilization on yields and soil properties in a long‐term trial     

Hermann Stumpe  Joachim Garz  Wilfried Schliephake  Lutz Wittenmayer  Wolfgang Merbach 《植物养料与土壤学杂志》2000,163(6):657-662

Investigations carried out at Field F3 of the Halle long‐term fertilization trials using data from 1974 to 1983 showed that with adequate supply of mineral N‐fertilizer soil organic matter (SOM) had no significant effects of yield. Similarly enhanced SOM did not justify a reduction of mineral N (Stumpe et al., 2000). The studies presented here examine the effects of the SOM differences existing after the termination of those trials in 1986 up until 1997 (then mainly differences of hardly decomposable SOM) in comparison to farmyard manuring with enhanced mineral N application (3‐factor‐experiment). As with total SOM, hardly decomposable SOM did not directly affect yields. The effects of FYM treatment observed at lower mineral‐N levels were compensated for by enhanced mineral‐N supply. The direct effect of FYM (40 t ha^—1) corresponded to a mineral‐N supply of about 60 kg ha^—1 and the residual effect to about 20 kg ha^—1. The differences of the C‐content in the soil at the beginning of the present studies continued throughout the experimental period of 12 years. In addition, significant differentiation has been caused by FYM and N fertilization in comparison to unfertilized treatments. The major finding is that differences in SOM content do not lead to yield differences on physically good soils (chernozem‐like soils) if appropriate compensation by mineral‐N fertilization takes place.  相似文献   

Ermittlung kinetischer Parameter der sauren Phosphatasen intakter Zuckerrübenwurzeln bei variierter Phosphaternährung     

Lutz Beißner  Wilhelm Rmer 《植物养料与土壤学杂志》1999,162(6):561-569

Determination of kinetic parameters of acid phosphatases in intact sugar beet roots of variable phosphorus nutrition Organically bound phosphorus has to be hydrolysed before its P can be taken up by plants. Both microbes and plant roots possess phosphatases, which could be of importance especially in soils with low concentrations of inorganic phosphorus in the soil solution. This could be the reason why nutrient uptake models underestimate the P-uptake by plants when P-mobilization by the phosphatases of roots is not taken into consideration. Therefore the activity of acid phosphatases (P_ase) was determined to answer the following questions: 1) To which extent does the root bound acid phosphatase (P_ase) follow Michaelis-Menten kinetics? 2) By which of the four linear transformations of the Michaelis-Menten equation (Lineweaver/Burk, Hanes, Eadie/Hofstee, Eisenthal/Cornish-Bowden) can plausible values of V_max and K_m be determined? 3) Which effect has the P nutrition of the plant on these kinetic parameters? Sugar beet plants were grown in full nutrient solution containing 1 and 100 μM P respectively. The P_ase activity of the intact roots was measured at pH 5 using p-nitrophenylphosphate (25—15000 μM p-NPP). V_max values were calculated per m root length. Acid phosphatase activity principally followed Michaelis-Menten kinetics. Transformations and calculations of V_max and K_m after Eadie/Hofstee and Eisenthal/Cornish-Bowden suggested the existence of at least two enzyme systems (P_{ase 1}, P_{ase 2}). The following kinetic parameters were found: P_{ase 1}: P deficient plants: V_max: 43—45 nmol m^—1 min^—1, K_m: 31—37 μM NPP; P sufficient plants: V_max: 7 nmol m^—1 min^—1, K_m: 47—53 μM NPP. P_{ase 2}: P deficient plants: V_max: 230—293 nmol m^—1 min^—1, K_m: 1579—3845 μM NPP; P sufficient plants: V_max: 123—171 nmol m^—1 min^—1, K_m: 3027—7000 μM NPP. Thus plants with sufficient P nutrition have a lower affinity to P_org and a lower hydrolysis of P_org. For P nutrition of crops P_{ase 1} might be the most important enzyme.  相似文献   

Effect of natural predators on Queensland fruit fly,Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) control by sterile insect technique (SIT)     

Darshana N Rathnayake  Elizabeth C Lowe  Polychronis Rempoulakis  Marie E Herberstein 《Pest management science》2019,75(12):3356-3362

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Cancer of unknown primary in a mare: case report and comparative pathology review     

Emily J. Brinker  Serena Ceriotti  Maria C. Naskou  Elizabeth A. Spangler  Erin S. Groover  Rachel L. A. L. T. Neto 《Journal of veterinary diagnostic investigation》2021,33(6):1142

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Assessment of aluminum sensitivity of maize cultivars using roots of intact plants and excised root tips     

Lutz Collet  Carlos de Leon  Malte Kollmeier  Nicole Schmohl  Walter J. Horst 《植物养料与土壤学杂志》2002,165(3):357-365

Maize cultivars (Zea mays L.) were evaluated for their aluminum (Al) sensitivity using intact plants and excised root tips exposed to 25 μM Al in nutrient solution of low ionic strength and pH 4.3. Aluminum supply increased callose formation and Al concentrations in root tips of intact plants as well as in excised root tips. Using intact plants, differences in Al sensitivity among cultivars could be characterized by Al‐induced callose formation, Al‐induced inhibition of root elongation, as well as Al contents in root tips as parameters. Significant correlations between Al‐induced callose formation and Al contents in root tips (r² = 0.64**) and inhibition of root elongation (r² = 0.80***) were found. Excised root tips did not show a significant Al‐induced inhibition of root elongation. While average Al‐induced callose formation was similar for root tips of intact plants and excised root tips, mean Al contents in excised root tips were up to 1.5‐fold higher than in root tips of intact plants after 24 h of Al treatment. Aluminum‐induced callose formation as found in excised root tips did neither correspond to Al‐induced callose formation nor to inhibition of root elongation of intact plants. The addition of 10 mM glucose to the incubation medium led to a significant increase in the elongation of excised root tips and a 2‐3‐fold increase in Al‐induced callose formation. Staining with triphenyl‐tetrazolium‐chloride (TTC) revealed increased viability of these root segments. However, these effects of glucose supply did not improve the characterization of the cultivars for Al resistance. The results presented suggest that Al exclusion mechanisms expressed in root tips of intact plants might be non‐operational in excised root tips. Therefore, the characterization of maize germplasm for Al resistance using excised root tips appears not to be reliable.  相似文献   

Expression analyses of digestive enzymes during early development and in adults of the chame fish Dormitator latifrons     

Rosa María Morelos‐Castro  Jos Cristbal Romn‐Reyes  Irasema Elizabeth Luis‐Villaseor  Jorge Saúl Ramírez‐Prez  Gustavo Alejandro Rodríguez‐Montes de Oca 《Aquaculture Research》2020,51(1):265-275

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Mapping quantitative trait loci for infectious salmon anaemia resistance in a North American strain of Atlantic salmon     

Forest M. Dussault  Keng Pee Ang  James. A. K. Elliott  Brian D. Glebe  Steven Leadbeater  Anthony J. Manning  Frank Powell  Elizabeth Grace Boulding 《Aquaculture Research》2020,51(1):80-90

Infectious salmon anaemia (ISA) is a highly virulent viral disease of Atlantic salmon that causes massive economic losses to infected aquaculture operations. Our goal was to detect and map quantitative trait loci (QTL) that confer resistance to ISA in an admixed commercial strain of Atlantic salmon that was largely founded from the Saint John River (SJR) in North America. Full‐sibling families were challenged with a virulent strain of ISA virus. Mortality was tracked during two annual trials with individual fish that survived to the end of the trial being classified as ‘resistant’, and those that died were classified as ‘susceptible’. Ten families with intermediate levels of mortality and an average size of 54.2 individuals were chosen for genotyping with a 50K SNP array designed for the SJR strain. Single nucleotide polymorphisms that were segregating within families were first used to make a composite 11K female linkage map that was then used to find the positions of QTL for ISA resistance using a half‐sib model. The dam‐based HS model detected a total of three QTL for ISA resistance including an experiment‐wide significant QTL on Ssa25 that accounted for 8.3% of the phenotypic variance and chromosome‐wide significant QTL on Ssa03 and on Ssa04 that accounted for 6.0% and 6.6% respectively. We conclude that classic linkage mapping within families continues to be an important method of detecting QTL for oligogenic traits in strains founded from multiple populations. Single nucleotide polymorphisms with moderate trait effects are being used to select within families for more ISA‐resistant strains of Atlantic salmon.  相似文献   

Taxonomic status of Oryza glumaepatula Steud. III. Assessment of genomic affinity among AA genome species from the New World, Asia, and Australia     

Bao-Rong Lu  Ma. Elizabeth B. Naredo  Amita B. Juliano  Michael T. Jackson 《Genetic Resources and Crop Evolution》1998,45(3):215-223

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