Impacts of land use/cover change on soil properties in the Mediterranean region of northwestern Jordan

This study was carried out to evaluate the effects of deforestation on physical and chemical properties of soils under native forest in the Mediterranean region of northwestern Jordan. Land use/cover maps of 1953, 1978 and 2002 were interpreted and analysed within GIS to quantify the shift from forest to rainfed cultivation. Six sites were sampled in a non‐changed forest and in cultivated fields, three for each. Different soil properties of texture, bulk density, organic matter, total nitrogen, pH, cation exchange capacity (CEC), phosphorous and potassium were analysed. Results showed that many forests were changed into cultivated lands at a rate more than the reforestation. Subsequently, adverse effects on the studied physical and chemical properties were observed. The most affected properties were particle size distribution, bulk density of surface soil and subsoil. Organic matter and CEC decreased in cultivated soil as compared to the forest soil. Cultivated soils were found to exhibit a significantly lower status in physical and chemical soil properties as compared to forest soils. This general decline in the soil physical and chemical properties, in turn, contributed to soil erosion, reduction of soil fertility and land degradation. There is an urgent need to improve soil quality by developing sustainable land use practices to reduce the rate of soil degradation and to ensure long‐term sustainability of the farming system in the study area and in similar biophysical settings. Copyright © 2008 John Wiley & Sons, Ltd.     

Pharmacokinetics and urinary excretion of sulphadimidine in sheep and goats

Pharmacokinetics and urinary excretion of sulphadimidine were determined in sheep and goats following a single intravenous injection (100 mg/kg). The disposition of the drug was described in terms of exponential expression: C _p= Be ^-βt. Based on total (free and bound) sulphonamide level in plasma, pseudo-distribution equilibrium was rapidly attained and the half-life for elimination was 3.88 ± 0.64 h and 4.00 ± 0.34 h in sheep and goats, respectively. Body clearance, which is the sum of all clearance processes was 88 ± 19 and 55 ± 4 ml/kg/h in sheep and goats. Based on this study a satisfactory intravenous dosage regimen might consist of 100 and 60 mg sulphadimidine/kg body wt for sheep and goats and should be repeated at 12 h intervals. The influence of disease conditions on predicted plasma levels remain to be verified experimentally. Three-quarters of an intravenously injected dose of sulphadimidine was excreted in the urine of sheep and goats within 24 h of administration. The drug was mainly excreted as free amine while acetylated drug constituted 7 and 8% of total drug content in the urine of sheep and goats, respectively.     

Ⅲ型分泌系统2转录因子YqeI对禽致病性大肠杆菌生物被膜调控机制的研究

生物被膜是导致细菌产生耐药性的主要原因之一,本文通过探究Ⅲ型分泌系统2（ETT2）转录调节因子YqeI对禽致病性大肠杆菌生物被膜形成的影响及其影响机制,为探究ETT2对禽致病性大肠杆菌致病机制的影响提供研究基础。利用Red同源重组的方法构建yqeI基因缺失株,并通过检测野生株与缺失株生物被膜形成能力、结合转录组学测序及荧光定量检测生物被膜基因表达量等,探究转录调节因子YqeI对禽致病性大肠杆菌生物被膜形成能力的影响。结果显示成功构建了yqeI基因缺失株,且yqeI的缺失并不影响生长曲线,但生物被膜形成能力显著下降,且相关生物被膜基因转录量显著下调。禽致病性大肠杆菌ETT2转录调节因子YqeI显著影响了禽致病性大肠杆菌生物被膜形成能力,为从ETT2及yqeI的角度发掘潜在的调控网络提供依据。     

Biology of milk thistle (Silybum marianum) and the management options for growers in north-western Pakistan

Milk thistle ( Silybum marianum ) is cultivated as a medicinal plant but it also can be a troublesome weed. It is an annual or biennial herb that prefers high rainfall and fertile soils. Milk thistle has become a widespread weed in north-western Pakistan, where it causes yield reductions ≤37% in wheat and poses harvesting problems due to its thorny nature. Shortcomings in cultural practises, such as a low crop seed rate, wide row spacing, broadcast fertilizer, and limited crop rotation have contributed to milk thistle becoming a severe weed problem for farmers in this region. This paper reviews the biology of milk thistle and discusses the possible management options for its control, considering the socioeconomic conditions of farmers in Pakistan.     

Is it possible to successfully rear meagre (Argyrosomus regius Asso 1801) larvae without using rotifers?

In hatcheries, meagre Argyrosomus regius larvae still depend on an adequate supply of rotifers and Artemia, as no artificial diet can totally fulfil their nutritional requirements. However, production of live feed is highly expensive and demands intensive labour and specific facilities. This study investigated the effect of a dietary regime without the use of rotifers, to simplify the meagre larval rearing protocol. Two feeding treatments (T₁ & T₂) are compared to investigate their effects on survival and growth of meagre larvae. In T₁, larvae were fed rotifers from 2 to 5 days post hatch (dph), and Artemia from 4 to 15 dph. In T_2, larvae were kept under dark conditions and fed Artemia from 6 to 15 dph. Standard larval length (SL) was significantly higher in T₁ (p < .01) until 8 dph in comparison with larvae reared initially without rotifers. No significant difference in SL was found among treatments (p = .187) at 15 dph. Significant difference was found among treatments in survival rate at 15 dph (p < .003). The survival rate observed at 15 dph in T₂ (30 ± 4.2%) represents an important finding, although the highest survival rate was observed in T₁ (45.0 ± 3.4%). This study showed that it is possible to conduct larval rearing of meagre without using rotifers. Nevertheless, further research efforts are still needed to improve these results in comparison with the common larval rearing protocol.     

稻壳和麦麸对鲜玉米秸秆青贮品质的影响

为更好地利用稻壳和麦麸,本试验将2者与新鲜玉米（Zea mays L.）秸秆按不同比例混合青贮,发酵60天后测定其青贮品质和营养成分,以期筛选出混贮的最佳比例。结果表明,与鲜玉米秸秆单独青贮（对照）相比,麦麸和鲜玉米秸秆混合青贮的干物质、可溶性碳水化合物和粗蛋白含量均显著提高（P<0.05）,但丁酸含量超过1%,发酵品质较差;与对照相比,稻壳与鲜玉米秸秆混合青贮的粗蛋白、可溶性碳水化合物含量和氨态氮/总氮的值均显著下降（P<0.05）;稻壳、麦麸与鲜玉米秸秆混合青贮的发酵品质与对照相当,但干物质含量显著提高（P<0.05）,且M1F1（5%麦麸+10%稻壳+85%鲜玉米秸秆）处理的Kaiser法评分最高。因此,建议将麦麸、稻壳和鲜玉米秸秆按5∶10∶85的鲜重比混合青贮。     

EFFECT OF POTASSIUM NUTRITION ON SOLUTE ACCUMULATION,ION COMPOSITION AND YIELD OF MAIZE HYBRIDS GROWN UNDER SALINE CONDITIONS

An experiment was conducted to study the response of two maize hybrids to external potassium (K) application under saline conditions. The data showed that there was an increase in the organic solute contents and sodium ion under salinity stress, though potassium, calcium, nitrogen and phosphorus were decreased. There was a non-significant effect of K application on glycinebetaine and total soluble sugar, however; the proline, protein and total free amino acids were increased with the application of external K. The enzymatic activity like nitrate reductase and nitrite reductase activity were severely reduced under salinity stress and improved by K application. The maize hybrids differed significantly for all the parameters discussed in the study except sugar, phosphorus and number of grain rows per cob. The increase in yield parameters was more pronounced under control than under saline conditions. The enhanced yield and yield components of these maize hybrids might be due to the quick response to external K application, resulting in high contents of leaf potassium, calcium, nitrogen and phosphorus. The results indicated that the maize hybrid ‘Pioneer32B33’ might perform better than ‘Dekalb979’ under saline conditions when sufficient potassium is applied in the rooting medium.     

Pharmacokinetics and dosage of chlorpromazine in goats

Pharmacokinetic parameters which describe the distribution and elimination of chlorpromazine in goats were determined. Following the intravenous administration of a single dose (2.5 mg/kg), disposition of the drug was described in terms of the biexponential expression C _p= Ae^-αt+ Be^-βt. Based on total (free and bound) chlorpromazine levels in plasma, pseudo-distribution equilibrium was rapidly attained, and the elimination half-life was 1.51 ± 0.48 h (mean ± SD, n = 8). Total body clearance, which is the sum of all clearance processes, was 80 ± 25 ml/min/kg. The curves of an animal representative of the group, based on individual rate constants associated with the two-compartment open model, showed that at 5 h after drug administration 8% and 6% of the dose were present in the peripheral and central compartments, respectively. The kinetic parameters of chlorpromazine determined at a dosage level of 10 mg/kg body weight in six goats showed that the drug followed first-order kinetics and kinetic parameters were similar after both dose levels. Based on these findings and therapeutic plasma levels, a satisfactory intravenous regimen should be 2.0 – 3.5 mg/kg and the drug action will persist for 5–6 h.     

Pharmacokinetics of sulphadimidine in normal and febrile dogs

Pharmacokinetic parameters which describe the distribution and elimination of sulphadimidine were determined in normal dogs and dogs in which fever was produced by an intravenous injection of escherichia and staphylococcal species of bacteria. Sulphadimidine was injected as a single intravenous bolus at the dose of 100 mg/kg and the kinetics of the drug were described in terms of the bi-exponential expression: C_p = Ae ^{-α t} + Be ^{-β t} . The distribution half-times of the drug were 1.52 h in the normal and 0.81 h in the febrile dogs. The drug distribution was significantly more rapid ( P < 0.05) in febrile than in normal dogs. Average ± SD values for the half-lives of the drug were 16.2 ± 5.7 h in normal and 16.7 ± 4.7 h in the febrile dogs. The apparent volume of distribution ( V ' _d (area)) was 628 ± 251 ml/kg in the normal dogs, and was not statistically different from 495 ± 144 ml/kg in the febrile dogs. The volume of the central compartment ( V ' _c ) was 445 ± 55 ml/kg in normal dogs and this was significantly higher ( P < 0.01) than the V ' _c of 246 ± 72 ml/kg in the febrile dogs. The body clearance was 22.4 ± 4.8 and 20.2 ± 3.6 ml/hour. kg in the normal and febrile dogs, respectively. The investigation revealed that the dosage regimen of sulphadimidine did not differ significantly between normal and febrile dogs.