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- Abstract：The objective was to study the effects of the specific inhibitors of PDEs on oocyte spontaneous meiotic maturation of mouse in vitro.Mouse cumulus-oocyte complexes(COCs) and denuded oocytes(DOs) were collected and cultured in a medium supplemented with specific inhibitors of PDEs and the rates of GVBD and PB1 extrusion were observed at different culture periods.The results indicated that both PDE3 inhibitor,cilostamide and PDE5 inhibitor,zaprinast,prevented oocyte spontaneous meiotic maturation.However,the PDE4 inhibitor,rolipram had no effect.The inhibitory effects of both cilostamide and zaprinast did not abate with increasing culture time but was reversed.Collectively,these results suggest that different PDEs have different roles in meiotic maturation of mouse oocytes.0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Exon 4 to intron 6 sequence of lipoprotein lipase(LPL) gene was cloned to determine genome characteristics in goose.The total DNA from goose serum was extracted.Two pairs of primers,P and Q,were designed to amplify the LPL gene exon 4 to intron 6 which were then cloned and sequenced.The results showed that the LPL gene exon 4 to intron 6 were 3 404 bp.Blasting the sequence homology among chicken,human,pig,mouse,cattle and cat showed that the DNA homology between goose and chicken was 91.9% which was the highest between goose and other species.The homology between goose and mammal(human,sheep,cattle and pig) was 74 to 77%.Also the hydrophilicity,average charge,surface probability and condon usage of amino acides coded by LPL gene exon 4 to exon 6 in goose were analysed.2|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The effect of protein elicitor from Alternaria tenuissima on main characteristics and enzymatic activity of co-tton.Was studied.The number of plant bell was significantly promoted by Alternaria tenuissima protein elicitor.The plant height,weight of single bell,lint-index,seed-index and lint-percent were increased in different degrees,whereas the weight of single bell hull was decreased.The protein elicitor promoted the growth and yield of cotton.Seed treatment by soaking seeds increased the unginned and lint-yield to 3 800.60 and 1 596.15 kg/hm2,respectively,being 22.15% and 26.11% higher than those of control.Many parameters were markedly improved by applying the protein activator at the right time and concentration.The Seed soaking plus spraying at the bud development stage was the most efficient.POD(peroxidase),NR(nitrate reductase) and SOD(superoxide dismulasc) were increased in all treatments by Alternaria tenuissima protein elicitor.MDA(malondialdehyde) decreased in all treatments studied.2|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
Establishment and evaluation of the core collection of peach (Prunus persica (L.) Batsch.) cultivars
Abstract：This study was aimed at establishing a core collection based on the analysis of MOR and SSR alleles of the primary core collection data of peach cultivars.The index of genetic diversity,and frequency ratio of retention and loss of alleles were studied in cluster and random samples at 9 sampling ratios.The cluster sampling method preceded random sampling,and cluster sampling of MOR combined with SSR at the sampling ratio of 80% was the best sampling strategy across sampling methods.Based on this sampling strategy,45 accessions were selected as the core collection of peach with the highest index of genetic diversity which retained 100% phenotypic characters and 96.6% alleles of primary core collection.Two alleles were lost at frequencies below 0.05 and all alleles were retained at frequencies between 0.05 and 1.The core collection developed was evaluated by using 6 quantitative traits and the data showed that it can satisfactorily represent the genetic diversity of the original collection of 558 peach accessions.The core collection of peach with a fair representation was established in this study based on pre-determined best sampling strategy.0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：Hail is a major natural calamity that is harmful to crops and often causes heavy losses in agricultural production.In this article,countermeasures are proposed to reduce the damage.Based on data from 20 meteorological stations in Beijing between 1978 and 2006,statistical analyses on spatial-temporal characteristics of hail distribution were made.The results showed marked temporal and spatial characteristics of hail in Beijing.The yearly,seasonal and daily variations were evident.Spatially,the high-frequency hail disaster occured mainly in mountainous areas rather than urban areas.In Beijing,the northeastern part is much more likely to have hail storms than the southern area.Possible countermeasures are proposed based on hail distribution and specific influence on crops.12|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to investigate influencing theory of stocking density on the incidence of breast blister for broilers,the behavior patterns of broilers caged in different densities,17 birds/m2,14 birds/m2 and 11 birds/m2 from the ages of four weeks to six weeks were observed.The results showed that broilers performed more sitting on the cage floor(arrived at 77.08%).The stocking density had the greatest effect on the behavior of broilers in 6 weeks compared with 4 and 5weeks.The duration and number of sitting were more in high density(17 birds/m2) than in low density(11 birds/m2)(P<0.05),while the duration and number of active behaviors,such as walking,drinking,feeding,preening,stretching and shaking in low density,were more than high density(P<0.05).Meanwhile the incidence of breast blister was significantly higher in high density than in low density(P<0.05).There was significantly negative correlation between the incidence of breast blister and the duration of shaking,preening and the number of sitting(r=-0.997,P=0.048;r=-0.999,P=0.028;r=-0.996,P=0.034).This present study showed that the duration or number of sitting,shaking and preening were much effected by stocking density,so as to the incidence of breast blister was done.1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Layer's health and welfare were compared under different cage conditions.Three commercial layer farms in Beijing were chosen(named A,B and C,respectively) and their stocking densities were 411,420 and 450 cm2,respectively.The environmental parameters,atmospheric NH3,CO2 and H2S concentrations were measured;and laying performance,mortality and incidence frequency of abnormal behavior of layers were recorded and analyzed.The results show that the wind speed,maximum wind gust and average wind speed of C were significantly higher than those of A and B(P<0.05);atmospheric temperature,wind chill,hot stress and dew point in A and C were significantly lower than those B(P<0.05).There were significant differences for average NH3 and CO2 concentration among the farms(P=0.003 and P=0.011) and NH3 and CO2 concentrations in C were lowest(1 mg/m3 and 83.73 mg/m3,respectively)(P<0.05); average H2S concentration was below the limit of 1 mg/m3.The birds from C were observed to have a greater sensitivity to outside visitors compared with those from A and B.Appearance score had no significant difference,but gait score and egg contamination score had significant difference among the farms(P=0.042 and P=0.023),in which gait score of C was significantly higher than that of A and B,and egg contamination score of C was significantly lower than that of A and B.The incidence frequency of abnormal behaviours had no significant differences among the farms.The hen-week egg production was significantly different among the farms(P=0.004),in which C was significantly higher than A and B(P<0.05);there had no significant differences for average egg mass,feed egg ratio,average egg production rate,egg production rate at peak period,leg diseases incidence,layer fatigue incidence,and mortality,except that the production period of C was significantly shorter than that of A and B(P<0.05).The study showed that great differences among the three cage conditions had greater effects on the health and welfare of layers than the stocking density and cage way themselves.To increase the current layer's health and welfare,more emphasis should be put on the improvement of the total environmental condition and management measures.0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The wind pressure coefficient used for greenhouse natural ventilation rate is similar to the wind load figure coefficient for greenhouse wind load calculation.In this paper authors differentiated them efficiently through theoretical analysis by which we can find the method of obtaining the wind pressure coefficient.Applying FLUENT software,in condition of window closed and opening to greenhouse of single-span and two-sides,authors simulated the wind pressure coefficient and wind load figure coefficient.Contrasted of two parameters,their values have a big difference;when the wind pressure coefficient is compared to wind load figure coefficient,the value of windward is smaller,the absolute value of leeward is bigger and in the same part the biggest difference is 60%.So,if the value of wind pressure coefficient used in greenhouse ventilation calculation is the same as the value of wind load figure coefficient,the calculation will result in a big error.0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This paper is concerned with a fuzzy support vector classifier in which the type of the figures for both the output of the training point and the value of the final fuzzy classification function is real number.The characteristic of real number is propitious to indicate the class of the figures as either positive or negative one.First,a fuzzy classification problem was formulated as a fuzzy coefficient programming problem.Then this programming was transformed into its optimal programming.As a result,we proposed a fuzzy support vector classification algorithm.In order to show its rationality,two examples were presented.In addition,we also proposed a strategy to decide the optimal threshold value in our algorithm.1|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The control differential equations for analysis of the cross section inner-force,the interface slip and bending deformation of a steel-concrete composite beam were established based on the Euler-Bernoulli beam model and partial-interaction theory to analyze the effect of the interface slip.The general equations of interface slip,cross section inner-forces and flexure deformation were build up and the deflection formulas of steel-concrete composite beams under various loads were obtained,which were compared with those from other models.1|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：A nonlinear finite element model was established and numerical analysis of casing plug joints of steel tubular was performed by the ANSYS software.The law of load capability was investigated by changing the ratio of diameter and length(l/d) and the ratio of the casing length and the main tube length(l/L),respectively.The influences of the casing thickness and the gap between main tube and casing for the load capability were also analyzed.The results indicated that the load capability and stiffness of the joint were both increased with the increases of both ratios of the l/d and the l/L.When the main tube thickness is equal to casing thickness,the load capability of joints will be the best.In terms of the gap between the main tube and casing,the results indicated the effect of the gap of 0.5-2.0 mm on the load capability is not prominent.0|6|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
