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1.
Intensification of cyprinid production has resulted in substantial increases in aquafeed demand for these species and a requirement for studies on new protein sources. Increased availability of presscakes from biodiesel crops may help to meet this requirement. The suitability of detoxified Jatropha curcas kernel meal (JKM), in combination with a dietary organic acid/salt blend (NDF), was tested in practical diets for juvenile common carp (Cyprinus carpio). Four treatment diets contained between 0% and 13.5% fishmeal with the fishmeal protein replaced by JKM (0%, 30%, 70%, and 100%). Four further diets of the same composition but including 0.5% NDF were also prepared, and all diets were fed to carps for eight weeks. There were no statistical differences in growth between diets containing JKM and the control. Furthermore, addition of dietary NDF significantly improved final weights, specific growth rates, feed conversion ratios, and protein efficiency ratios. Body composition analysis showed a significant impact of dietary JKM inclusion on increasing body lipid content. The addition of NDF showed a tendency to lower body lipid content (P = 0.11). JKM is a suitable protein source in diets for carp, and the inclusion of 0.5% of NDF proved to be beneficial.  相似文献   
2.
Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped.  相似文献   
3.

Purpose

The in situ stabilization of multielement-contaminated agricultural soils has limited effectiveness when using common single amendments. This study examined the use of drinking water treatment residues (WTR), based on (hydr)oxides of Fe, Al, or Mn, as a cost-effective solution to optimize the immobilization of metals (Cd, Pb, Zn) and As.

Materials and methods

Trace elements (TE) bioavailability was assessed under semi-controlled conditions in a pot study cultivating winter wheat (Triticum aestivum L. cv. Tiger) until maturity. An Fe-based WTR and a Mn-based WTR, applied at rates of 0.5 and 1% (m/m), were related to effects of lime marl (LM) application. Additionally, a bioassay with earthworms (Dendrobaena veneta) was conducted. Both bioassays were compared with measurements of NH4NO3-soluble, diffusive gradients in thin film (DGT)-available and soil solution TE concentrations, representing well-established surrogates for mimicking the bioavailable element fractions in soil.

Results and discussion

The application of the Fe-based WTR reduced As accumulation in vegetative wheat tissues (by up to 75%) and earthworms (by up to 41%), which corresponded with the findings from soil chemical analyses and improved plant growth and earthworm body weight. However, As concentrations in cereal grains were not affected, Cd or Pb accumulation by wheat was not mitigated, and Zn uptake was enhanced. By contrast, the Mn-based WTR effected the greatest reduction in Pb uptake, and lowered Cd transfer to wheat grain (by up to 25%). Neither the NH4NO3-soluble nor DGT-available concentrations matched with Cd and Zn accumulation in plants or earthworms, indicating interferences due to competition for binding sites according to the biotic ligand model.

Conclusions

The results obtained in this study suggest that a bioassay with key species prior to field application should be mandatory when designing in situ stabilization options. The application of WTR to an agricultural soil strongly affected TE bioavailability to plants and earthworms. Low application rates tended to improve biomass production of biota. Higher application rates involved risks (e.g., P fixation, TE inputs), and none of the amendments tested could immobilize all targeted elements.
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4.
<正>近期伊利诺伊大学的J.A.Almeida博士、 Hans H.Stein博士以及Carsten Pedersen博士联手展开体重对于标准化回肠蛋白质和氨基酸吸收率的影响试验,结论证明,20 kg以下的仔猪回肠对于粗蛋白和氨基酸的吸收率比20~50 kg的育成猪和50~110 kg的育肥猪低。而且同一猪群的不同猪只也表现出吸收率的差异性。例如,在测定的300只仔猪中粗蛋白和氨基酸的吸收率  相似文献   
5.
6.
Wood modification with alkoxysilanes   总被引:4,自引:0,他引:4  
Wood was treated with three different alkoxysilanes which are able to undergo a sol–gel process: tetraethoxysilane (TEOS), methyl triethoxysilane (MTES) and propyl triethoxysilane (PTEO). Two types of treatments were compared: impregnation of fibre saturated wood with monomeric silane solutions, and impregnation with pre-hydrolysed partly oligomeric silanes. Wood properties such as cell wall bulking, anti-swelling efficiency (ASE), moisture uptake and durability were more significantly improved in samples treated with monomeric silanes than in samples treated with oligomeric silanes. SEM-EDX mapping showed that this treatment resulted in a higher degree of silicon incorporation into the cell wall, although the weight percent gain (WPG) was lower compared to the treatment with pre-hydrolysed partly oligomeric silanes. The resistance against soil micro-organisms was enhanced in the initial phase of incubation especially in those samples treated with organo-functional-alkoxysilanes. In miniaturised block tests with the white-rot basidiomycete Trametes versicolor, an improved durability was observed within the test period. During an air conditioning step, a weight loss of the treated samples occurred which was accompanied by a reduction in bulking and ASE. The initial reduction of moisture uptake observed after treatment diminished almost completely. This effect was explained by an ageing of the gels in the wood cell wall which is a consequence of uncompleted hydrolysis and condensation of the silanes during the treatment.  相似文献   
7.
We synthesized nano-scaled periodic ripple patterns on silicon and titanium dioxide (TiO(2)) surfaces by xenon ion irradiation, and performed adsorption experiments with human plasma fibrinogen (HPF) on such surfaces as a function of the ripple wavelength. Atomic force microscopy showed the adsorption of HPF in mostly globular conformation on crystalline and amorphous flat Si surfaces as well as on nano-structured Si with long ripple wavelengths. For short ripple wavelengths the proteins seem to adsorb in a stretched formation and align across or along the ripples. In contrast to that, the proteins adsorb in a globular assembly on flat and long-wavelength rippled TiO(2), but no adsorbed proteins could be observed on TiO(2) with short ripple wavelengths due to a decrease of the adsorption energy caused by surface curvature. Consequently, the adsorption behavior of HPF can be tuned on biomedically interesting materials by introducing a nano-sized morphology while not modifying the stoichiometry/chemistry.  相似文献   
8.
Beech wood (Fagus sylvatica L.) was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU). The equilibrium moisture content (EMC) of wood modified with DMDHEU calculated on a dry modified basis is reduced. Previous results have shown that the modification with DMDHEU does not alter the capillary condensation; therefore, the reduction in EMC seems exaggerated. The equilibrium constants of the Hailwood–Horrobin model (K d and K h) and the molecular weight of a hypothetical polymer of modified wood capable of adsorbing one molecule of water (W i) were calculated from the EMC on a dry modified wood basis (M) and on a dry wood basis (M R). The hypothetical polymer was also calculated by stoichiometry (W c) and compared to W i to estimate the number of operative OH groups. The number of operative OH groups decreased when M was used, in contradiction with the previously obtained results of differential heat of adsorption (∆H s). Therefore, the use of M R is recommended for the analysis of moisture sorption in wood modified with DMDHEU.  相似文献   
9.
Objective – To compare the placement feasibility and amount of bone trauma induced by 3 intraosseous (IO) access techniques in cats: an automatic impact penetration device (A), an automatic rotary insertion device (B), and a manual IO needle (C). Design – Prospective ex vivo study. Setting – University. Animals – Eighteen adult mixed breed feline cadavers. Interventions – Cadavers provided 72 total IO insertion locations divided equally between the right and left humerus and tibia. The 3 IO techniques were randomly allocated to these locations. Time to successful insertion, ease of insertion, and success rate were recorded. Each insertion site was analyzed for the number of bone fragments and defect diameter by computed tomography. Measurements and Main Results – Device B had lower time of insertion (P=0.01) compared with devices A and C. Device B had better ease of insertion scores (P<0.01) compared with devices A and C. No differences were detected between insertion sites (tibia versus humerus). No differences in the number of bone fragments, defect diameter, or success rate were detected among devices (P=0.06, 0.31, and 0.14, respectively). Conclusions – All 3 IO access methods evaluated yield acceptable results. Device B is significantly faster and easier to place in cat cadavers when compared with other methods.  相似文献   
10.
Trustworthy eco-labels provide consumers with valuable information on environmentally friendly products and thus promote green consumerism. But what makes an eco-label trustworthy and what can government do to increase consumer confidence? The scant existing literature indicates that low governmental involvement increases confidence. This suggests that government should just provide the basic legal framework for eco-labeling and leave the rest to non-governmental organizations. However, the empirical underpinning of this conclusion is insufficient. This paper analyses consumer confidence in different organic food labeling regimes with varying degrees of governmental involvement. Using unique and detailed survey data from the US, United Kingdom, Denmark, and Sweden, the analysis shows that confidence is highest in countries with substantial state involvement. This suggests that governments can increase green consumerism through active and substantial involvement in eco-labeling.  相似文献   
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