西方蜜蜂产浆量的动态遗传研究

应用条件和非条件遗传效应分析方法对3个西方蜜蜂(Apis mellifera L.)品种的蜂群产浆量、台浆量和台基接受率进行了发育遗传研究。结果表明：蜂群产浆量、台浆量在各个时期均存在显著或极显著的基因型方差,台基接受率在大部分时期存在显著或极显著的基因型方差,说明这3个性状主要由遗传因素决定。条件遗传分析发现,在某些无法检测到非条件方差的时期存在显著水平的条件方差,证明在产浆期的不同阶段,3个性状都有基因的新表达。同一性状不同时期的遗传相关分析表明：蜂群产浆量以及台浆量在各个时期均检测到显著或极显著的基因型相关,台基接受率在大多时期存在显著的基因型相关,表明控制产浆量和台浆量早期表现的遗传效应总是以相同的方式调节后期的表现,而台基接受率则不然。成对性状之间的相关研究表明：蜂群产浆量和台浆量之间在各个时期存在显著或极显著的遗传相关,说明2性状基因效应之间的协同作用是一致的,而蜂群产浆量和台基接受率之间在大多时期存在显著的遗传相关,但在一些时期没有相关,2性状之间的基因效应协同作用较差。     

固定化细胞分布对动力学影响的模型化研究

通过对固定化Gluconobacter oxydans和Bacillus cereus的活细胞系统的研究,提出了固定化细胞不均匀分布模型,将此类分布与均匀分布(最劣分布模型)进行比较,分析了它们对固定化细胞内部的基质浓度分布、有效速率因子和选择率的影响,指出不均匀分布和均匀分布对于该固定化活细胞系统的动力学行为无显著影响,这一模型分析结果在实验中得以验证。通过无因次化分析,建立了适用于固定化生物催化剂动力学研究的模型方法。     

一类三维非线性系统空间周期解的存在性及唯一性

本文研究了一类描述天然林内红松林种群变化的三维非线性教学模型     

Discovery of isolated patches ofIcerya purchasi byRodolia cardinalis: A field study

The discovery of isolated patches of prey by the natural enemies of the cottony-cushion scaleIcerya purchasi Maskell was tested in the field on potted plants ofAcacia baileyana and citrus between November and February in South Australia. The survival of scales to adults in patches in the 4 fortnightly releases (cohort sets) was not significantly different between location-1 (under anAcacia tree harbouring scales and its natural enemies) and location-2 (about 500 m away from the nearest host plant of the scale). The temporal distribution of mortality in the scale cohorts was described by the Weibull model. The proportion of scales surviving at the 2 locations (on the 3^rd & 6^th fornight) was not significantly different suggesting that the total effect of all the mortality factors on the scales at the 2 locations was the same. The trends in prey patches destroyed in time could be explained from the period of activity of the natural enemies in the field.Rodolia cardinalis (Mulsant) had discovered the prey patches within a fortnight of the release of scale crawlers. The results substantiate earlier reports thatRodolia can find and destroy isolated scale colonies.      

Infection, reinfection, and vaccination under suboptimal immune protection: epidemiological perspectives

The SIR (susceptible-infectious-resistant) and SIS (susceptible-infectious-susceptible) frameworks for infectious disease have been extensively studied and successfully applied. They implicitly assume the upper and lower limits of the range of possibilities for host immune response. However, the majority of infections do not fall into either of these extreme categories. We combine two general avenues that straddle this range: temporary immune protection (immunity wanes over time since infection), and partial immune protection (immunity is not fully protective but reduces the risk of reinfection). We present a systematic analysis of the dynamics and equilibrium properties of these models in comparison to SIR and SIS, and analyse the outcome of vaccination programmes. We describe how the waning of immunity shortens inter-epidemic periods, and poses major difficulties to disease eradication. We identify a "reinfection threshold" in transmission when partial immunity is included. Below the reinfection threshold primary infection dominates, levels of infection are low, and vaccination is highly effective (approximately an SIR model). Above the reinfection threshold reinfection dominates, levels of infection are high, and vaccination fails to protect (approximately an SIS situation). This association between high prevalence of infection and vaccine failure emphasizes the problems of controlling recurrent infections in high-burden regions. However, vaccines that induce a better protection than natural infection have the potential to increase the reinfection threshold, and therefore constitute interventions with a surprisingly high capacity to reduce infection where reduction is most needed.     

Characterization of a continuous supermacroporous monolithic matrix for chromatographic separation of large bioparticles

A continuous supermacroporous monolithic chromatographic matrix has been characterized using a capillary model, experimental breakthrough curves, and pressure drop experiments. The model describes the convective flow and its dispersive mixing effects, mass transfer resistance, pore size distribution, and the adsorption behavior of the monolithic matrix. It is possible to determine an effective pore size distribution by fitting the capillary model to experimental breakthrough curves and pressure drop experiments. The model is able to describe the flow rate dependence of the experimental breakthrough curves. Mass transport resistance was due to: (i) dispersive mixing effects in the convective flow in the pores; and (ii) slow diffusion in the stagnant film covering the surface within each pore, under adsorption conditions. The monolithic matrix can be described by a very narrow pore size distribution, illustrating one of the advantages of the gel. A broader pore size distribution results in increased band broadening. This can be studied easily using the model developed in this investigation.     

重庆市城市化与生态环境交互关系的协整分析

运用协整理论和误差修正模型考察了重庆市1978-2007年期间城市化与生态环境相互作用的关系,遴选出作用于生态环境的2项主要的城市化指标和影响城市化的4项主要的生态环境指标,它们能反映出交互作用的机制。结果发现:1978-2007年,重庆市城市化与生态环境之间存在长期均衡关系,城市化对生态环境的正向作用明显强于生态环境对城市化的反向影响,误差修正系数较长期协整方程中的系数要小。从长期来看,城市化水平对生态环境变化的解释能力正在逐步增强,这充分证明生态环境功能的弱化是城市化步伐推进的必然结果。就城市化对生态环境的响应效果而言,一方面城市化是影响重庆市生态环境的重要原因,另一方面生态环境对城市化也存在着反作用。生态环境对城市化进程产生外在压力,但这一反馈机制往往具有一定的滞后效应。城市化对解释生态环境预测方差分解起着重要作用,然而生态环境对城市化预测方差的贡献度较小。     

栀子粗提物对抑郁模型小鼠行为学及海马神经发生的影响

目的观察栀子粗提物对慢性轻度应激模型小鼠行为学及海马神经发生的影响。方法采用10种不同应激源实施对小鼠连续10周刺激,从第3周开始口服给予栀子粗提物3个剂量治疗8周后,测定各组小鼠行为学改变,并采用NeuN和BrdU免疫组化观察海马区神经细胞的增殖情况。结果栀子粗提物高剂量组蔗糖饮水量明显增加（P〈0.05）,强迫游泳不动时间明显缩短（P〈0.05）;NeuN阳性表达升高（P〈0.01）,BrdU阳性细胞的面数密度亦显著增加（P〈0.05）。结论栀子粗提物对抑郁模型小鼠行为有明显改善作用,并能显著促进海马区神经元发生,提示栀子粗提物具有良好的抗抑郁作用。     

东北羊草草原综合生态因子对微生物生长的作用──IRM模型的研究

本文从分解者亚系统水平研究了东北羊草草原土壤中微生物生长的季节变化．多种生态因子的季节变化及环境因子对微生物的综合作用规律。微生物总数,总生物量和总呼吸强度的季节动态呈单峰上凸式曲线变化,８月份有明显的高峰值出现,它们分别为：２６８９．０×１０￣４个／ｇ·干土、２５．４１×１０￣（０３）ｇ／ｇ·干土、０．８９５２×１０￣（－３）ｇＣＯ＿２／ｇ·干土·ｄ。土壤生态因子的季节变化与土壤微生物呈现不同程度的正相关和负相关。同时利用ＩＲＭ的模型─—探讨了生态因子对微生物生长的综合作用规律：生态因子对微生物生长的综合作用指数ｒ＿ｎ在整个生长季节中为０．００３１８－０．１１１５,其中７－９月份ｒ＿ｎ较大,对出生物生长的限制作用较小,微生物生长较快,５、６和１０月份ｒ＿ｎ较小,对微生物生长限制作用较大,微生物生长较慢。     

Prey-taxis destabilizes homogeneous stationary state in spatial Gause–Kolmogorov-type model for predator–prey system

We consider a continuous taxis-diffusion-reaction system of partial-differential equations describing spatiotemporal dynamics of a predator–prey system. The local kinetics of the system is defined by general Gause–Kolmogorov-type model. The predator ability to pursue the prey is modelled by the Patlak–Keller–Segel taxis model, assuming that movement velocities of predators are proportional to the gradients of specific cues emitted by prey (e.g., odour, pheromones, exometabolites). The linear stability analysis of the model showed that the non-trivial homogeneous stationary regime of the model becomes unstable with respect to small heterogeneous perturbations with increase of prey-taxis activity; an Andronov–Hopf bifurcation occurs in the system when the taxis coefficient of predator exceeds its critical bifurcation value that exists for all admissible values of model parameters. These findings generalize earlier results obtained for particular cases of the Gause–Kolmogorov-type model assuming logistic reproduction of the prey population and the Holling types I and II functional responses of the predator population. Numerical simulations with theta-logistic growth of the prey population and the Ivlev functional response of predators illustrate and support results of the analytical study.