Understanding the epidemiology of sheep-pox outbreaks among vaccinated Algerian sheep and post vaccination evaluation of the antibodies kinetics of the commercially used vaccine

Sheep pox is a disease of veterinary concern to small ruminant producers and veterinary diagnosticians, because of the associated tangible economic losses. The epidemiological analysis of sheep pox, among vaccinated sheep flock in Algeria from 2007 to 2016, showed that the disease outbreaks occurred every year and across all Algeria region with an average of 44.9 outbreaks per year, these outbreaks correlate with the region climate, the flocks’ density and the transhumance practices. The one-year post vaccination antibody kinetics evaluation study of the commercially used vaccine in Algeria demonstrated a mild humoral response, the neutralization index range between 0.73 and 1.22. Therefore, the present study recommends a challenge study, using a virulent local strain, to evaluate the vaccine efficacy. Furthermore, quality control approach for the vaccine production processes is required.     

重金属对水稻光合作用和同化物输配的影响

光合速率测定表明,0.025～1.0mmolL的Cu2+、Cd2+和Hg2+显著抑制水稻叶片的光合速率,且抑制程度随Cu2+、Cd2+和Hg2+浓度的增高而增强。示踪动力学分析表明,0.5mmolL的Cu2+、Cd2+和Hg2+抑制光合产物在叶内不同状态间的转化,影响叶中光合产物的输出,导致叶内小分子糖的累积,使叶片光合速率受糖浓度增高的反馈调节而下降。电泳分析表明,Cu2+、Cd2+和Hg2+抑制叶内淀粉酶同功酶的表达,并进而抑制光合同化物在叶内可输配态和暂贮态之间的转化。     

稻米淀粉糊老化动力学研究

以不同类型稻米为原料，用旋转粘度仪研究较稀浓度淀粉糊的老化动力学，以预测和控制稻米淀粉糊老化。结果表明：稻米淀粉糊呈假塑性流体的特征，随存放时间的延长，其流变指数上升，淀粉糊的刚性增大。用流变指数和一级化学反应动力学模型能较好的描述淀粉糊的老化特性。淀粉糊的老化与其分散相的凝聚、沉淀和连续相的特性有关。淀粉糊中直链淀粉和支链淀粉的相互作用会使其老化进一步加深。     

煤矸石燃烧过程中的动力学特性研究

采用非等温热重分析法研究煤矸石燃烧动力学过程，通过热重（ＴＧ）、差热（ＤＴＡ）、微商热重（ＤＴＧ）实验，提出煤矸石挥发分析出过程的特性参数和反应动力学方程，测算了反映煤矸石燃烧放热特性的差热峰面积指标，并分析探讨了氯化钠等碱金属化合物对煤矸石燃烧动力学过程的影响规律。     

Soil organic matter decomposition driven by microbial growth: A simple model for a complex network of interactions

Priming effects are expressions of complex interactions within soil microbial communities. Thus, we aimed at building a microbial population growth model which could deal with different substrates, resources and populations. Our model divides the decomposition/growth process at the population level in two stages, mimicking mechanisms taking place at molecular and cellular scales: (1) the first stage is a reversible process whereby microbial biomass capture their substrate to form a complex within definite proportions; (2) the second stage is the irreversible rate-limiting utilization of substrate per se. It is supposed to be a first order process with respect to the quantity of complex. We put these assumptions into equations using an analogy with chemical reactions at equilibrium. We show that this model (1) provides a mathematical formalism that bridges the gap between first order decay of substrates and Monod kinetics; (2) sets constraints on the possible combinations of microbial functional traits, yielding microbial strategies in agreement with observations; (3) allows to model both positive and negative priming effects, and more generally complex interactions between the various components of a soil system. This model is designed to be used as a kernel in any soil organic matter model.     

不同钾水平下杂交稻~(14)C-光合产物运转动力学

用~(14)CO_2饲喂杂交籼稻威优35功能叶,研究光合产物在体内的运转。结果表明,源叶光合产物的输出及库(幼叶或谷粒)同化物输入的百分率(v)和时间(t)之间的关系均极显著地符合回归方程v=V[t+k)/[K_m+(t+k))。在分蘖期,主茎顶部完全展开叶可输出66％～79％的~(14)C-光合产物;低钾处理使源叶输出潜能和速率下降,过量钾处理加快光合产物输出速率;未展开的幼叶可输入28％～59％的~(14)C-光合产物,低钾不仅降低输入潜力,且使输入延迟。在灌浆期,剑叶可输出83％～97％的光合产物,其中77％～88％运往谷粒;低钾处理延迟光合产物输出时间,降低输出速率;过量钾处理降低输出潜力,但提高输出速率;低钾处理还降低同化物输入谷粒的比例和速率,过量钾处理降低同化物输入谷粒的比例,但提高输入速率。所以,从总体上看,低钾和过量钾处理都不利于新固定的同化物在体内的运输。     

Phosphorus concentrations in sodium bicarbonate and citric acid extracts from arid sandy soils

Abstract

The aim of this study was to compare 1% citric acid and 1% bicarbonate solutions as extracts for the determination of phosphorus in sandy arid‐zone soils, using 64 samples from the Kalahari dunefield. For 56 of these samples, measured phosphorus concentrations were <8 ppm in both extracts, and for these 56 samples the acid‐extractable and bicarbonate‐extractable phosphorus concentrations were statistically equivalent. For the remaining 8 samples, with phosphorus concentrations >8 ppm in at least one of the extracts, phosphorus concentrations in citric acid extracts were consistently greater than those in bicarbonate extracts.     

多壁碳纳米管对五氯苯酚的电催化还原动力学研究

化学气相沉积法在石墨基体上制备多壁碳纳米管,作用电极,应用于电催化还原处理水中典型难降解多氯代有机物-五氯苯酚。考察了多壁碳纳米管对五氯苯酚的电催化还原特性和动力学。结果表明,电催化还原处理五氯苯酚主要受温度,电解质,催化剂,偏压的影响。动力学研究表明,电催化还原处理五氯苯酚反应是准一级反应。反应速率常数受温度(T),阴极电解质浓度(M),催化剂含量(Q),阳极电解质浓度(M′),偏压(E)的影响。动力学方程为:C=C0exp(0.01658T0.351M0.263Q0.370M′0.436E0.775t)。     

A quantitative study of native soil phosphorus supply to plants

Abstract

Rhodes grass (Chloris gayana Kunth ) plants were grown on various soil types In order to study the relationships between the available and hardly available soil P fractions. Results indicate that when plants are grown intensively in soils for long periods without additional P fertilization, recharge rate of the available fraction of soil P becomes a limiting factor. An approach to determine the recharge rate, using data on plant uptake and changes in sodium bicarbonate extractable soil P content are suggested.