Spatiotemporal trends in reference evapotranspiration over South Korea     

Hwang  Ju Ha  Azam  Muhammad  Jin  Maeng Seung  Kang  Yong Ho  Lee  Jae Eun  Latif  Muhammad  Ahmed  Rehan  Umar  Muhammad  Hashmi  Muhammad Zaffar 《Paddy and Water Environment》2020,18(1):235-259

Paddy and Water Environment - The universal phenomena of global warming caused by climate change have direct linkage with different hydro-meteorological variables which in turn affect the...  相似文献   

Effects of supplementary fennel (Foeniculum vulgare) essential oil in diet on growth and reproductive performance of the ornamental fish,Convict cichlid (Cichlasoma nigrofasciatum)          下载免费PDF全文

Azam Sotoudeh  Sakineh Yeganeh 《Aquaculture Research》2017,48(8):4284-4291

This study evaluated the effects of diet containing 0 (C: control), 75 (D₁), 100 (D₂), 125 (D₃) and 150 (D₄) mg kg^?1 F. vulgare essential oil on growth and reproductive performance of C. nigrofasciatum. A total of 225 Convict cichlids female with mean weight (1.65 ± 0.02 g) were distributed into 15 glass aquaria (15 fish tank^?1) in triplicate treatments. During 40 days of experimental period, fish fed at 3% of their body weight daily. At the end of experiment, growth indices, gonadosomatic index and reproductive indices were determined. The best feed conversion ratio was obtained in D₄ (1.19 ± 0.03, P < 0.05). The addition of F. vulgare essential oil did not have any statistical effects on other growth indices (specific growth rate, weight gain and condition factor). Total survival rates in all treatments and control were uniformly high, ranging from 93% to 97% (P > 0.05). F. vulgare essential oil has no negative effect on survival rate of C. nigrofasciatum. There were no significant differences among protein content of fish body (P > 0.05). The lowest value of fat content (26.5 ± 0.5%) was observed in D_2, and it had significant difference with control and other groups (P < 0.05). The ash percentage in treatments fed with F. vulgare essential oil were higher than control fish (P < 0.05). The highest moisture content was detected in D₄ (72.68 ± 0.19%) and D₂ (71.23 ± 2%) groups. Among the used dosage, D₄ was the most effective dosage that could significantly increase GSI (11.06 ± 1.55%), fecundity (340 ± 21) and hatching ratio (92.33 ± 1.63%). There were no significant differences in diameter of eggs among various treatments (P > 0.05).  相似文献   

Efficacy of insect larval meal to replace fish meal in juvenile barramundi,Lates calcarifer reared in freshwater     

Katya  Kumar  Borsra  M. Z. S.  Ganesan  Dev  Kuppusamy  Giva  Herriman  Max  Salter  Andrew  Ali  Sayed Azam 《International Aquatic Research》2017,9(4):303-312

International Aquatic Research - The present experiment was conducted to evaluate the efficacy of dietary protein from black soldier fly, Hermetia illucens, larval meal (BSFL) to replace fish meal...  相似文献   

Spatio-temporal variability of drought characteristics across Pakistan     

Lee  Jae Eun  Azam  Muhammad  Rehman  Saif Ur  Waseem  Muhammad  Anjum  M. Naveed  Afzal  Arslan  Cheema  M. J. M.  Mehtab  Muhammad  Latif  Muhammad  Ahmed  Rehan  Umar  Muhammad  Sarwar  Abid  Rehman  Syed Aziz Ur 《Paddy and Water Environment》2022,20(1):117-135

Climate change in Pakistan has a great impact on the spatial and temporal variation of precipitation and ultimately alters the frequency and duration of droughts. In this study, spatial and temporal trend analyses of precipitation and droughts were observed at 58 meteorological stations across Pakistan from 1981 to 2018. The existing trend analysis methods were evaluated to address the issue of serial correlation in the climatic data. Results of precipitation analysis showed significant decreasing trends in winter (November, December) and significant increasing trends were observed in summer (June and September) at a confidence level of 95 percent. The magnitude of the precipitation trends showed the highest variation during summer season and the least variation in winter season. Rotated Principal Component (RPC) analysis showed the severe droughts (high positive loading) in southeastern side (Sindh province) of Pakistan due to lack of summer rains. Furthermore, variance correction approaches are identified as the most suitable in coping with the effect of serial correlation. The highest drought frequencies were observed in the southern areas of Pakistan and the drought events are expected to occur more frequently in the late winter, early spring, and early autumn, while droughts were expected to occur least frequently in summer.

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Synthesis of 15N-labelled microbial biomass in soil in situ and extraction of biomass N     

F. Azam  R. L. Mulvaney  F. J. Stevenson 《Biology and Fertility of Soils》1989,7(2):180-185

Summary A Pakistani soil (Hafizabad silt loam) was incubated at 30°C with varying levels of ¹⁵N-labelled ammonium sulphate and glucose (C/N ratio of 30 at each addition rate) in order to generate different insitu levels of ¹⁵N-labelled microbial biomass. At a stage when all of the applied ¹⁵N was in organic forms, as biomass and products, the soil samples were analysed for biomass N by the chloroform (CHCl₃) fumigation-extraction method, which involves exposure of the soil to CHCl₃ vapour for 24 h followed by extraction with 500 mM K₂SO₄. A correction is made for inorganic and organic N in 500 mM K₂SO₄ extracts of the unfumigated soil. Results obtained using this approach were compared with the amounts of immobilized ¹⁵N extracted by 500 mM K₂SO₄ containing different amounts of CHCl₃. The extraction time varied from 0.5 to 4 h.The amount of N extracted ranged from 27 to 270 g g^–1, the minimum occurring at the lowest (67 g g^–1) and the maximum at the highest (333 g g^–1) N-addition rate. Extractability of biomass ¹⁵N ranged from 25% at the lowest N-addition rate to 65%a for the highest rate and increased consistently with an increase in the amount of ¹⁵N and glucose added. The amounts of both soil N and immobilized ¹⁵N extracted with 500 mM K₂SO₄ containing CHCl₃ increased with an increase in extraction time and in concentration of CHCl₃. The chloroform fumigation-extraction method gives low estimates for biomass N because some of the organic N in K₂SO₄ extracts of unfumigated soil is derived from biomass.  相似文献   

Transformation of 15N-labelled leguminous plant material in three contrasting soils     

F. Azam  R. L. Mulvaney  F. J. Stevenson 《Biology and Fertility of Soils》1989,8(1):54-60

Summary Two soils from Pakistan (Hafizabad silt loam and Khurrarianwala silt loam) and one from Illinois, USA (Drummer silty clay loam) were incubated with ¹⁵N-labelled soybean tops for up to 20 weeks at 30°C. Mineralization of soybean ¹⁵N was slightly more rapid in the Pakistani soils, and after 20 weeks of incubation, 50%, 53%, and 56% of the applied ¹⁵N was accounted for as (NH₄ ⁺+NO₃ ^–)-N in Drummer, Hafizabad, and Khurrarianwala soils, respectively. Potentially mineralizable N (determined by anaerobic incubation) varied between 1.5% and 10% of the applied ¹⁵N in the three soils at different stages of incubation; somewhat higher percentages were mineralizable in the Pakistani soils than in the Drummer soil. From 3.7% to 9% of the applied ¹⁵N was accounted for in the microbial biomass. From 10% to 32% of the applied N was recovered in the humic acid and fulvic acid fractions of the organic matter by sequential extraction with Na₄P₂O₇ and NaOH; from 12% to 49% was recovered in the humin fraction. Of the three soils, Drummer soil contained more ¹⁵N as humic and fulvic acids. In all cases, the ¹⁵N was approximately equally distributed between the humic and fulvic acid fractions. A significant percentage of the humin ¹⁵N (52%–78%, equivalent to 8%–34% of the applied ¹⁵N) occurred in non-hydrolyzable (6 N HCl) forms. Of the hydrolyzable ¹⁵N, 42%–51% was accounted for as amino acid-N followed in order by NH₃ (17%–30%), hydrolyzable unknown forms (20%–22%), and amino sugars (6%–2%). The recovery of applied ¹⁵N for the different incubation stages was 87±22%. Recovery was lowest with the Khurrarianwala soil, presumably because of NH₃ volatilization losses caused by the high pH of this soil.  相似文献   

Use of 15N isotope dilution for quantification of N2 fixation associated with roots of kallar grass (Leptochloa fusca (L.))     

K. A. Malik  Y. Zafar  R. Bilal  E. Azam 《Biology and Fertility of Soils》1987,4(1-2):103-108

Summary Leptochloa fusca (L.) Kunth (kallar grass) has previously been found to exhibit high rates of nitrogen fixation. A series of experiments to determine the level of biological nitrogen fixation using ¹⁵N isotopic dilution were carried out in nutrient solution and saline soil. In the nutrient solution, E. coli inoculated plants were taken as non-nitrogen-fixing control. It was observed that nearly 60%–80% of the plant N was derived from atmospheric fixation. Estimations based on the N difference method gave much lower values (18%–35%). In experiments with saline soil which was initially sterilized with chloroform fumigation, a mixed culture of N₂-fixing rhizospheric isolates from kallar grass roots was inoculated and planted to kallar grass. Uninoculated treatments were regarded as controls. The soil was previously labelled with ¹⁵N by adding cellulose and (¹⁵NH₄)₂SO₄. The results of these studies showed fixation values of 6%–32% when estimated by ¹⁵N dilution, whereas by the N difference method 54% of the plant N was estimated to be derived from fixation. This discrepancy is due to the increase in root proliferation due to inoculation, which results in greater uptake of soil N. The distribution of ¹⁵N in different fractions of the soil-N indicted isotopic dilution due to bacterial fixation of atmospheric N₂.  相似文献   

Pharmacokinetics of Mirtazapine and Its Main Metabolites after Single Oral Administration in Fasting/Fed Horses     

Mohammad-Reza Rouini  Hoda Lavasani  Behjat Sheikholeslami  Vahid Nikoui  Azam Bakhtiarian  Micaela Sgorbini  Mario Giorgi 《Journal of Equine Veterinary Science》2013

Mirtazapine (MRZ) is a human antidepressant drug that is metabolized, predominantly by the cytochrome P450 enzyme system, to 8-OH mirtazapine (8-OH MRZ) and dimetilmirtazapine (DMR) metabolites. In veterinary medicine, this drug is currently administered to cats and dogs with anorexia, although it could also have applications as an antidepressant, antiemetic, and analgesic agent in these species. The aim of this study was to assess the pharmacokinetics of MRZ and its metabolites DMR and 8-OH MRZ in horses. Six healthy female horses were administered MRZ (2 mg/kg) in fasting and fed states according to a balanced crossover study design. Plasma MRZ and metabolite concentrations were evaluated by high-performance liquid chromatography fluorescence detection method. Pharmacokinetic profiles of MRZ and DMR were similar (detected from 0.5 up to 34 and 48 hours, respectively), with an MRZ AUC_0-N/DMR AUC_0-N ratio range varying between 1.1 and 1.7. Surprisingly, 8-OH MRZ was undetected. Most of the pharmacokinetic parameters were not altered by food, with the exception of the time required to reach maximum concentration; this showed a statistical increase in subjects in the fasting state as compared with the fed state. However, because MRZ is an active substance intended for long-term administration, the slight increase of the time required to reach maximum concentration is not considered to be of any clinical consequence. In conclusion, the pharmacokinetic parameters demonstrated in this study suggest that MRZ is suitable for oral administration in the horse. However, further investigations are required to evaluate both its safety and effectiveness in this animal species.  相似文献   

Quantifying sources of environmental contamination with Toxocara spp. eggs     

E.R. Morgan  D. Azam  K. Pegler 《Veterinary parasitology》2013

A rich body of work has reported levels of infection with Toxocara species in definitive hosts, and the frequency of eggs in the environment, in many different regions and situations. These have greatly increased our understanding of the relationship between egg excretion from companion and wild animals and the risk of human infection by inadvertent ingestion of eggs from soil and other environmental reservoirs. Nevertheless, it is difficult to compare studies directly because of vagaries in sampling and laboratory methods, a preponderance of prevalence rather than abundance data, and a lack of studies that systematically sample different sympatric definitive host populations. Such comparisons could be instructive, for example to determine the relative contributions of different definitive host populations and categories to environmental contamination in specified areas, and hence guide priorities for control. In this article we use estimates of host density and infection levels in the city of Bristol, UK, as a case study to evaluate the relative contribution of sympatric cats, dogs and foxes to overall environmental contamination with eggs. Results suggest that dogs, especially those less than 12 weeks of age, dominate total egg output, but that this is modified by degree of access to public areas and removal of faeces, such that foxes could take over as the primary source of eggs. Results and conclusions are likely to differ among specific locations. The general aim is to show how an improved quantitative framework for epidemiological studies of Toxocara spp. egg contamination can help to advance understanding and the effectiveness of control strategies in future.  相似文献   

Tillage and N application effects on crop yield,N uptake and soil properties in a corn-based rotation     

Sayyed Shahaboddin Moinoddini  Mehdi Nassiri Mahalati  Azam Borzooei 《Archives of Agronomy and Soil Science》2017,63(8):1150-1162

The objective of this study was to determine the influence of tillage methods (conventional tillage (CT) and minimum tillage (MT)) and N rates (0, 50, 150, 250 kg N ha^?1) on crop yield, N uptake and soil organic carbon (SOC), bulk density (BD), total N (TN), electrical conductivity (EC), pH and soil nutrient contents on a clay-loam near Hashtgerd, Iran. A successive corn-based rotation (2012–2014) was conducted as a split-plot in a randomized complete block design in which tillage methods were considered as main plots, and N rates as subplots. Tillage had no significant effect on corn 2012 and canola 2012–2013 grain yields. CT and MT systems showed different critical N rates to reach their maximum grain yield in corn (2013) and wheat (2013–2014). MT system required more N application to reach its maximum grain yield. Tillage × N rate effect on none of the soil properties was significant. Tillage had no significant (P ≤ 0.05) effect on soil pH, BD, TN and SOC. However, soil EC of 0–5 cm depth in MT system was higher than CT system by 64%. MT system under higher N application could increase corn grain yield, but on the other hand probably adversely changes soil chemical properties.  相似文献