Soluble Mn(III) in suboxic zones

Soluble manganese(III) [Mn(III)] has been thought to disproportionate to soluble Mn(II) and particulate Mn(IV)O2 in natural waters, although it persists as complexes in laboratory solutions. We report that, in the Black Sea, soluble Mn(III) concentrations were as high as 5 micromolar and constituted up to 100% of the total dissolved Mn pool. Depth profiles indicated that soluble Mn(III) was produced at the top of the suboxic zone by Mn(II) oxidation and at the bottom of the suboxic zone by Mn(IV)O2 reduction, then stabilized in each case by unknown natural ligands. We also found micromolar concentrations of dissolved Mn(III) in the Chesapeake Bay. Dissolved Mn(III) can maintain the existence of suboxic zones because it can act as either an electron acceptor or donor. Our data indicate that Mn(III) should be ubiquitous at all water column and sediment oxic/anoxic interfaces in the environment.     

Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis

Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. O?mycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known o?mycete avirulence genes.     

Probing the faintest stars in a globular star cluster

NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed an ultradeep color-magnitude diagram for this cluster. We see a clear truncation in each of its two major stellar sequences. Faint red main-sequence stars run out well above our observational limit and near to the theoretical prediction for the lowest mass stars capable of stable hydrogen burning in their cores. We also see a truncation in the number counts of faint blue stars, namely white dwarfs. This reflects the limit to which the bulk of the white dwarfs can cool over the lifetime of the cluster. There is also a turn toward bluer colors in the least luminous of these objects. This was predicted for the very coolest white dwarfs with hydrogen-rich atmospheres as the formation of H(2) and the resultant collision-induced absorption cause their atmospheres to become largely opaque to infrared radiation.     

The intra- and inter-assessor reliability of measurement of functional outcome by lameness scoring in horses

The objective of this study was to assess the reliability of lameness scoring in horses. One veterinary surgeon examined nineteen lame horses on four occasions. Gait was recorded by camcorder, and scored from 0 to 10 ranging from sound to non-weight bearing lameness. A global score of overall change in lameness during the study was also determined for each horse. To measure intra-assessor reliability of the scoring systems, one veterinary surgeon scored videotapes of the horses' gaits on two occasions. To measure inter-assessor reliability, three veterinary surgeons viewed the videotapes, assigning individual lameness scores plus global scores to each horse. Reliability of individual lameness scoring was good intra-assessor, but only just within our acceptable limit inter-assessor. However, global scoring of change in lameness throughout the study was found to be reliable overall. Since clinician scoring is commonly used to assess lameness in horses, this is an important finding, fundamental to future clinical studies.     

基于OpenCV的精量喷雾图像处理技术

为了实现喷雾设备的精量喷雾、有效节省农药的使用量,基于开源计算机视觉OpenCV技术,提出了一种能实现精量喷雾的图像处理技术。通过提取、识别绿色植株,计算出绿色区域的面积,并以此为依据,对其进行试验验证。结果表明:该系统能够实现对植株图像的高速处理,并能计算出图像中待施药植株的表面积,为喷雾设备的精准喷雾打下了基础。     

振动铲式马铃薯收获机的设计与仿真分析

马铃薯作为世界主要的经济作物之一,其种植规模不断扩大。为此,针对小规模种植地区的种植情况,设计了振动铲式马铃薯收获机,动力来源为8.8~11k W小四轮拖拉机。同时,运用Solid Works构建各结构及整机的三维模型,并借助ADAMS仿真软件对振动铲进行动力学和振动仿真分析。结果显示:仿真后的位移、速度及加速度曲线随着时间的变化都保持平稳,其加速度数值在-2.7~1.7mm/s2范围内;仿真后的振动频率处于1 4~2 4 Hz范围内,与土壤的固有频率1 4 HZ很接近,说明该振动频率能够实现挖掘铲的最佳挖掘效果。     

番茄高产栽培管理方法

正一、品种选择选择高产、耐高温高湿、高抗病毒病和耐根结线虫的品种,要求早熟的还应选择中早熟或自封顶类型品种,如金粉二号、金粉早粉红等;要求采摘期长的选中晚熟无限生长型品种。基地番茄栽培要选择厚皮、硬肉、耐贮运的品种。二、种子处理番茄种子表面一般附着早疫、叶霉、溃疡病等病原菌,可以对种子进行温汤浸种处理和药剂消毒。温汤浸种先把种子放在凉水中浸泡10～20分钟,然后立即投入到50℃的水中浸泡,始终保持水温并不断搅拌,20～30分钟后捞出     

健康养猪对乡村振兴与农民增收的调研与对策建议——以扬州市为例

为更好地保障国家重大战略粮食安全和稳定猪肉价格，实现畜牧业助力“乡村振兴”和“建设新时代鱼米之乡”。扬州市作为苏中主要的养猪地区，近年来随着国家级生猪产能调控基地获批，及一大批省市级养殖基地建设，扬州市生猪养殖规模不断扩大，生产效益不断提高。本文以扬州市生猪养殖为研究对象，紧密围绕健康养猪对乡村振兴与农民增收，进行了科学的调研分析及针对问题提出对策建议。首先，通过对扬州市境内大中小规模养猪进行全面调研和摸底，掌握养猪业对当地市场需求供应及农户经济收入的影响。其次，精准掌握近三年生猪养殖常见的传染病和繁殖疾病，分析发病原因、传播途径及病理损伤。对养猪业造成的具体危害细致分析，为政府科学决策提出相应举措，尤其是传染性病和繁殖疾病对健康养殖的威胁和挑战。最后，提出建立科研单位与当地养殖企业服务对接，不断引进先进养殖技术、提高猪群繁殖效率、保障农民收入的增加。该文为健康养猪对乡村振兴提供详实的科学调研数据，及农民增收提出宝贵的对策建议。     

不同八角家系高接穗条成活率及结实量分析

本研究以八角不同家系(1号、3号、4号、7号、11号、12号、14号)为穗条,以容县天堂山树龄相似的八角为砧木,进行高接,并对成活率及生长情况调查研究。结果表明:八角7号家系在容县天堂山高接后,成活率最高100%,枝条最长为121.25 cm,结出的鲜果最多为20个,鲜果重0.261 1 kg,平均角数为8.25个,风干重0.044 kg。