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101.
A 7‐year‐old Quarter Horse gelding was referred for magnetic resonance (MR) imaging due to chronic left hindlimb lameness localised to the foot. On presentation, a previously undiagnosed draining tract was identified at the plantar aspect of the pastern. Radiographs revealed severe osteolysis of the navicular bone. Positive contrast MR fistulography was performed using a gadolinium based contrast agent following conventional MR imaging of the left hind foot. Fistulography allowed characterisation of a fistulous tract, which was closely associated with the deep digital flexor tendon, navicular bursa and osteomyelitis of the navicular bone.  相似文献   
102.
Urban nature is of vital importance for human well-being in an increasingly urbanized world. Despite the wide variety of urban greenspaces, previous research has mostly focussed on parks and in particular presence of trees. Although streets are fundamental urban structures and offer an array of green elements beyond trees, the perception and valuation of other kinds of roadside vegetation by urban residents is understudied so far. This study explores the range of roadside vegetation and associated ecosystem services perceived by city dwellers in densely populated inner city districts of two German cities. Further, we explored how wild-grown roadside vegetation is valued by interviewees. Results confirmed the important role of trees but also demonstrated that city dwellers perceive a variety of cultivated and “wild” green components other than trees. Respondents attached a wide range of meanings and values to roadside greenery and showed a surprisingly high awareness of associated ecosystem services. Wild urban roadside vegetation met with high approval, although planted and maintained vegetation was preferred. Our study illustrated that trees and other elements of roadside vegetation fulfil important functions in the view of the public. For many respondents, ecological and economical functions of roadside vegetation were more important than orderliness. This indicates opportunities for enhancing the biodiversity of urban streetscapes. As public green spaces are in short supply in many cities, enhancing cultivated and wild roadside vegetation could help to deliver ecosystem services in the areas near where people move and live.  相似文献   
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对取自德国Solling的挪威云杉林的不同枯枝落叶层样品进行了一系列浸提实验,结果表明,枯落物分解程度、水∶物的比值和浸提液pH值都是元素浸提的主要控制因素.多数阳离子的浸提受到H+交换机制的很大影响,较低的pH值会导致较高的浸提量;而较高的pH值和稀释作用导致的pH值升高会导致较低的浸提量.在水∶物的比值增加到某一数值之前,水∶物的比值增加会导致浸提液内元素浓度与枯落物元素含量的新平衡,并导致浸提量增大.另外一方面,水∶物的比值增加导致的pH值升高会成为新的限制因素,导致较低的浸提量,尤其对于2、3价阳离子.这两种作用机制的复合效应使浸提量与水∶物的比值的关系曲线非常复杂.建立了森林枯枝落叶层元素含量(T, μmol(+)·kg-1)、浸提液pH值、水∶物的比值(W,kg·kg-1)对元素浸提量(Y,μmol(+)·kg-1枯落物)影响的数学模型.对Na+、K+,Ca2+、Mg2+、Mn2+、Al3+和Fet,模型为Y=A+(T-A)·exp(-B·pH)/[1+C·exp(-W)];对H+,模型为Y=a+bW c.对严重酸化的枯枝落叶层元素的浸提,不存在所期盼的最优水∶物的比值.水∶物的比值较低时,元素浓度比值变化较大;在水∶物的比值较高时,元素数量比值变化较大.但对严重酸化的枯枝落叶层元素进行浸提时,可把各枯枝落叶层的饱和含水量作为一个折中的水∶物的比值.挪威云杉林枯枝落叶层的未分解层、半分解层、全分解层的饱和含水量分别为3.4、3.2、2.0 kg·kg-1.  相似文献   
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106.
The increasing use of recirculating nutrient solutions and drainage water for irrigation purposes requires effective sanitation methods to minimise the dispersal of plant pathogens. Among these, plant viruses are of particular interest because they cannot be cured. A new disinfection system was tested in regard to its ability to inactivate plant viruses in nutrient solution in greenhouses. Potassium hypochlorite produced onsite by an electrolytic disinfector and injected once weekly into the nutrient solution by a sensor, prevented the dispersal of Pepino mosaic virus in the tomato crop. The management program assures that virus particles released from infected plants do not accumulate, forming an infectious virus reservoir which represents an inoculum potential in the hydroponic system. Both tested applications at 0.2 or 0.5 mg free chlorine/l nutrient solution for 60 or 30 min ensured virus inactivation and did not cause phytotoxicity. The yield of tomato plants grown in KCIO-treated nutrient solution was even significantly higher than that of control plants. PepMV-infected source plants solely bore unmarketable tomatoes showing discoloration. By inhibiting the dispersal of PepMV and the infection of test plants, the amount of unmarketable tomato fruits was reduced rigorously in treated variants.  相似文献   
107.
Influence of the VA-Mycorrhiza on P uptake and recovery potential of corn (Zea mays L.) under water stress conditions In a seven week pot experiment the influence of the VA-Mycorrhiza on P uptake and water stress tolerance of corn was investigated. During the eight day water stress period the VAM-plants took up less phosphorus than the control plants. However, during the successive five day recovery period under a normal water regime the VAM-plants showed an increased root growth and an enhanced phosphorus uptake compared with the control plants. The free prolin concentration was lower in leaves of VAM-plants than in those of nonmycorrhizal plants at the end of the water stress period, pointing to a different water stress tolerance.  相似文献   
108.
A procedure is proposed for the determination of the authenticity of white wines from four German wine-growing regions (Baden, Rheingau, Rheinhessen, and Pfalz) based on their content of some major, trace, and ultratrace elements. One hundred and twenty-seven white wine samples possessing a certificate of origin, all of the 2000 vintage, were analyzed. The concentrations of 13 elements (Li, B, Mg, Ca, V, Mn, Co, Fe, Zn, Rb, Sr, Cs, and Pb) were determined in wine diluted 1:20 by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Indium was routinely used as internal standard. Supervised pattern recognition techniques such as discriminant analysis and classification trees were applied for the interpretation of the data. A quadratic discriminant analysis (QDA) allowed the four regions to be discriminated with 83% accuracy when using only eight variables (Li, B, Mg, Fe, Zn, Sr, Cs, and Pb), and the prediction ability for classifying new samples was 76%. By use of a second method, a decision tree, the classification of samples coming from the four regions could be performed with an accuracy of 84% when only four elements were used: Li (very low in samples from Baden), Zn (abnormally low in the samples from the Rheingau), and Mg and Sr (both important for the differentiation between Pfalz and Rheinhessen samples). For this method, the prediction ability was only 74% in the identification of unknown samples. The robustness of the QDA model was not good enough, and therefore the tree is better recommended for the classification of new wine samples from these areas of German wine production.  相似文献   
109.
An important feature of maintaining the agricultural stability in millennia-old mountain oases of northern Oman is the temporary abandonment of terraces. To analyse the effects of a fallow period on soil microbial performance, i.e. microbial activity and microbial biomass, samples of eight terrace soils abandoned for different periods were collected in situ, assigned to four fallow age classes and incubated for 30 days in the laboratory after rewetting. The younger fallow age classes of 1 and 5 years were based on the records of the farmers recollections, the two older fallow age classes of 10–20 and 25–60 years according to the increase in the d -to- l ratio of valine and leucine enantiomers. The increase in these two ratios was in agreement with that of the d -to- l ratio of lysine. The strongest relationship was observed between the increase in the d -to- l ratio of lysine and the decrease in soil microbial biomass C. However, the most stringent coherence between the increase in fallow age and soil properties was revealed by the decreases in cumulative respiration and net N mineralisation rates with decreasing availability of substrate to soil microorganisms. During the 30-day incubation following rewetting, relative changes in microbial activity (respiration and net N mineralisation) and microbial biomass (C and N) indices were similar in the eight terrace soils on a fallow age-class-specific level, indicating that the same basic processes occurred in all of the sandy terrace soils investigated.  相似文献   
110.
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