雷州黑鸭内脏器官的结构观察

对6只雷州黑鸭(公母各半)的消化器官、生殖器官和免疫器官进行解剖及切片观察,了解其内在器官的形态位置和结构特征。观察结果显示,雷州黑鸭的消化管长,有发达的肌胃和较发达的小肠,消化吸收功能强;雷州黑鸭产青壳蛋的概率高,蛋壳结构坚实,蛋黄颜色呈深红色,有红心海鸭蛋之称;雷州黑鸭的胸腺、脾脏发达,免疫力强。     

Interactive Sorption of Metal Ions and Humic Acids onto Mineral Particles

The sorption of metal ions (Pb2+, Zn2+ and Cu2+) and soil humic acids (HA) from aqueous solutions onto mineral particles (sand, calcite and clay) was investigated using a batch equilibrium system. The sorption reactions in two- component systems (heavy metals-mineral particles and humic acids- mineral particles), as well as interactions in three-component system (heavy metals-humic acids-mineral particles) were examined. Results showed that the presence of humic acids, dissolved or bound onto mineral surfaces, considerably influenced the fixation of heavy metals. The various effects, depending on mineral type, humic concentration and specific metal-ion, were observed in three- component system. Sorption of Cu2+-ions on all minerals studied rapidly increased as the concentration of dissolved HA increased. The amount of Pb2+-ions sorbed on sand slightly decreased, while on kaolin increased between 15 and 20%. Sorption of Zn2+-ions on all minerals studied decreased at pH 4. At pH 5.5 the sorption of Zn2+-ions onto calcite decreased, while on kaolin and sand increased as a function of the humic acid concentration giving the curve with maximum at c(HA) = 2.5 mmol C L-1. At pH 6.5 sorption onto kaolin and sand increased. This effect occurs as a result of the conditional stability constant of Zn-HA complexes increasing at higher pH which in turn promotes the chelation of Zn2+-ions to mineral- bound humic substances. The enhanced sorption of metal ions from the aqueous phase in three-component systems is not only the result of mineral sorption of free metals but also the result of chelation with HA sorbed on the mineral surface.     

水稻"三控"施肥技术在高要市的示范应用效果

介绍了高要市2007~2008年连续2年开展水稻"三控"施肥技术示范的效果.试验结果表明:与当地习惯施肥相比,水稻"三控"施肥技术每667 m2产量早季增加26.98 kg、晚季增加52.95 kg.增产率分别为7.29%和12.64%;早季节省氮肥28%、节约肥料成本18%左右,晚季节省氮肥13%、节约肥料成本14.5%;每667 m2纯收益增加85.76-139.45元:氮肥利用率提高22.2%-59.5%,产投比提高11.3%-15.6%;同时,水稻"三控"施肥处理的稻株更健壮、抗倒性和抗病虫能力更强,稻飞虱和稻纵卷叶螟危害率分别减少了21.97%和48.00%.     

Symbiotic bacteria direct expression of an intestinal bactericidal lectin

The mammalian intestine harbors complex societies of beneficial bacteria that are maintained in the lumen with minimal penetration of mucosal surfaces. Microbial colonization of germ-free mice triggers epithelial expression of RegIIIgamma, a secreted C-type lectin. RegIIIgamma binds intestinal bacteria but lacks the complement recruitment domains present in other microbe-binding mammalian C-type lectins. We show that RegIIIgamma and its human counterpart, HIP/PAP, are directly antimicrobial proteins that bind their bacterial targets via interactions with peptidoglycan carbohydrate. We propose that these proteins represent an evolutionarily primitive form of lectin-mediated innate immunity, and that they reveal intestinal strategies for maintaining symbiotic host-microbial relationships.     

新疆落叶松地理种源区划

以新疆落叶松地理种源试验的代表性区试点布尔津、富蕴和哈密的种源子代综合性状的主分量结果为依据，参考气候因子和阻隔基因交流的自然条件，将新疆落叶松区划为2个种源区和4个种源亚区，即阿尔泰山种源区（编号Ⅰ），含西部种源亚区（编号Ⅰ1）和东部种源亚区（编号Ⅰ2）；天山种源区（编号Ⅱ），含东部种源亚区（编号Ⅱ1）和中东部种源亚区（编号Ⅱ2）。     

Stress and fold localization in thin elastic membranes

Thin elastic membranes supported on a much softer elastic solid or a fluid deviate from their flat geometries upon compression. We demonstrate that periodic wrinkling is only one possible solution for such strained membranes. Folds, which involve highly localized curvature, appear whenever the membrane is compressed beyond a third of its initial wrinkle wavelength. Eventually the surface transforms into a symmetry-broken state with flat regions of membrane coexisting with locally folded points, reminiscent of a crumpled, unsupported membrane. We provide general scaling laws for the wrinkled and folded states and proved the transition with numerical and experimental supported membranes. Our work provides insight into the interfacial stability of such diverse systems as biological membranes such as lung surfactant and nanoparticle thin films.     

基于光谱参数的棉花叶面积指数监测和敏感性分析

研究棉花冠层光谱参数对不同叶面积指数的响应,建立棉花叶面积指数光谱参数最佳估测模型,并对所选光谱参数进行敏感性分析.利用高光谱仪测定不同时期不同叶面积指数条件下的棉花冠层光谱反射率.结果表明,694 nm和1099nm分别为可见光和近红外波段区域内与叶面积指数相关性最好的波段,并用于改进前人所建立的光谱参数;宽范围动态...     

T and B lymphocytes in horses persistently infected with equine infectious anaemia virus

The percentage of T and B lymphocytes in the peripheral blood of horses chronically infected with equine infectious anaemia (EIA) virus was determined and the results were compared with the percentage of these cells in healthy uninfected horses. Cells with membrane receptors for sheep erythrocytes (T and active T lymphocytes) were determined by E and A rosette techniques, while cells with receptors for the C3b component of complement and those with receptors for mouse erythrocytes (B lymphocytes), were determined by the EAC rosette method. The percentage of Fc positive cells was assayed by the EA rosette test.The majority of peripheral blood lymphocytes (PBL) from both uninfected and EIA-infected horses formed rosettes of each kind with only three erythrocytes indicating a low density of the corresponding receptors on the cell membrane under the condition of the assays used. The percentage of T lymphocytes in the peripheral blood of diseased horses (52.4±1.6%), as detected by E rosettes, was significantly (p<0.01) higher than in control animals (42.4±3.5%). In clinically healthy horses 8.9±1.1% of PBL were identified by A rosettes as active T cells, whereas animals with a chronic form of EIA had a much lower (p<0.001) percentage of these cells (4.7±0.7%). In the B lymphocyte subpopulations the percentages of cells bearing Fc and C3b receptors were markedly elevated (p<0.001) in EIA-infected horses (24.7±0.8% and 42.8±2.2% respectively) as compared to uninfected animals (15.1±1.4% and 29.6±1.2% respectively). Receptors for mouse erythrocytes, as yet undescribed on equine PBL, were demonstrated in approximately equal proportions on lymphocytes from EIA-infected (24.8±1.5%) and uninfected horses (24.3±2.1%).     

丘陵红壤区旱稻需水量试验的研究

应用“坑测法”测定了旱稻需水量 ,结果表明 :中亚热带丘陵红壤地区旱稻需水量为 5 14 .0 mm。该需水量约为同期降雨量的 6 1% ,一般年景不用灌溉。过多过少水量都影响旱稻生长 ;低于 35 0 .0 mm不能成穗。旱稻根系发达 ,吸水吸肥和抗旱能力强 ,特别适宜丘陵地区种植。