Approach for a Vegetation Index Resistant to Atmospheric Effect

Estimation of vegetation information at the regional scales using remote sensing data has been a subject of considerable research and development in view of the importance of land-atmosphere interactions in global climate change. The normalized difference vegetation index (NDVI) approach has been a popular method. Many experiments on the' ground had indicated that NDVI was closely correlated to the leaf area index (LAI) and photosynthetically active radiation (PAR). In order to determine LAI and PAR accurately in a region by means of NDVI from available satellite inages, atmospheric effects must be largely elucidated. Although substantial progress has been made to improve the NDVI method, removal of the atmospheric effects has not been completely satisfactory. The atmospheric effect on NDVI has been contemplated in the experiments conducted at Yucheng Experimental Comprehensive Station, China. Kaufman and his colleagues also had verified the atmospheric effect on NDVI even the effect still existed after using 5s algorithm to remove rayleigh scattering and ozone absorption. For this reason they presented an atmosphere resistant vegetation index (ARVI) which was based on correlation between blue and red wave bands of the atmo. The authors also proposed the values for calculating IAVI in absence of the gound-based spectrum-radiometer measurements to approximately correct the atmosphere effect. For summer condition: γ↑=0. 656–0.006 sinθ+0.124 Sin2θ for rural area, visibility〉22 km γ↑=0. 656–0. 018 sinθ+0. 106 Sin2θ for urban area, Visibility〉22 km γ↑ =0. 722–0. 011 sinθ+0.165 sin2θ for rural area, 7 km〈visibility〈20 km γ↑=0. 646–0.002 sinθ+0, 140 sin2θ for urban area, 7 km〈visibility〈20 km γ↑ =0. 788+0. 015 sinθ+0. 206 sin2θ for rural area, visibility<5 km γ↑ =0. 643+0. 007 sinθ+0. 174 sin2θ for urban area, visibility〈5 km For winter condition γ↑ =0. 677+0. 019 sinθ+0. 200 sin2θ for rural area, visibility>22 km γ↑ =0. 642-0. 009 sinθ+0. 196 sin2θ for urban area, visibility>22 km γ↑ =0. 785+0, 040 sinθ+0. 237 sin2θ for rural area, 7 km〈visibility〈20 km γ↑ =0. 664+0. 021 sinθ+0.223 sin2θ for urban area, 7 km〈visibility〈20 km γ↑ =0. 893+0.060 sinθ+0. 273 sin2θ for rural area, visibility〈5 km γ↑ =0. 686+0. 051 sinθ+0. 249 sin2θ for urban area, visibility〈5 km The correction factor γ↑ was a crucial parameter for upward path radiance. It varied with atmosphere aerosol co ndition and viewing angles and was deviated from 1. Based on the above analysis: the range of γ↑ was from 0.65 to 1.21. For hazy atmosphere conditions it varied more significantly with aerosol type and viewing angles than clear condition. The percentage of error of vegetation index for the two cases studied were less than 4 % as compared with 16% and 31% using NDVI, and 19% using ARVI.     

Hydrolysis of concentrated raw starch: A new very efficient α-amylase from Anoxybacillus flavothermus

A new α-amylase from Anoxybacillus flavothermus (AFA) was found to be effective in hydrolyzing raw starch in production of glucose syrup at temperatures below the starch gelatinization temperature. AFA is very efficient, leading to 77% hydrolysis of a 31% raw starch suspension. The final hydrolysis degree is reached in 2-3 h at starch concentrations lower than 15% and 8-24 h at higher concentrations. AFA is also very efficient in hydrolyzing the crystalline domains in the starch granule. The major A-type crystalline structure is more rapidly degraded than amorphous domains in agreement with the observed preferential hydrolysis of amylopectin. Amylose-lipid complexes are degraded in a second step, yielding amylose fragments which then re-associate into B-type crystalline structures forming the final α-amylase resistant fraction. The mode of action of AFA and the factors limiting complete hydrolysis are discussed in details.     

Heat–moisture treatment under mildly acidic conditions alters potato starch physicochemical properties and digestibility

Potato starch was subjected to heat–moisture treatment (HMT; 120 °C, 3 h) under mildly acidic conditions (pH 5, 6, or 6.5 [control]) at moisture levels of 15, 20 or 25%. HMT starches exhibited significantly delayed pasting times and reduced overall paste viscosities, amylose leaching, and granular swelling characteristics relative to native starch, as well as enhanced levels of thermo-stable resistant starch (≈24%). HMT appeared to alter/enhance short-range chain associations (FT-IR) within amorphous and/or crystalline regions of starch granules. However, the extent of physicochemical change and RS enhancement during HMT was most facilitated by a mildly acidic condition (pH 6) at higher treatment moisture levels (20 or 25%). These conditions promoted limited hydrolysis of amylopectin molecules, primarily at α-(1 → 6) branch points, likely enhancing mobility and interaction of starch chains during HMT. Thus, a slightly acidic pH might reduce conditions and/or timeframe needed to impart physicochemical changes and reduced digestibility to potato starch.     

Genetic diversity among late blight resistant and susceptible potato genotypes

RAPD polymerase chain reaction analysis was used to study the genetic diversity among a wild potato variety Solanum demissum (very resistant to late blight) and six potato cultivars (Hanna, Lady-Olympia, Lady-Rosetta, Spunta, Diamant and Cara) varied in their resistance to Phytophthora infestans. Cluster analysis of six potato genotypes showed that, all tested genotypes were separated into two clusters (1 and 2). Cluster 1, included only the wild potato variety (S. demissum), whereas cluster 2 divided into two groups (G1 and G2). Late blight high resistant cultivars Hanna and Cara were grouped in G1. Group 2 included the moderate resistant cultivar Spunta and the susceptible cultivars Diamant, Lady-Rosetta and Lady-Olympia. The potato cultivars that showed highest genetic similarity to the wild potato variety were the resistant cultivars Hanna and Cara. Lowest genetic similarity was obtained with the susceptible cultivars Lady-Rosetta, Diamant and Lady-Olympia. RAPD primer K17 yielded a band with molecular weight of 936 bp found in all susceptible potato cultivars (Lady-Rosetta, Lady-Olympia and Diamant). On the other hand, band with molecular weight of 765 bp were detected in the wild potato and the resistant cultivars Hanna and Cara. Results of this study suggested that, the RAPD marker technique could be beneficial for revealing the genetic variability of different genotypes of potato varied in their resistibility to late blight.     

大气污染对38种木本植物的伤害特征

38种苗龄1—2a生的木本植物盆栽于相对清洁区(华南植物园和2个污染点：佛山市南海区五星和佛山市禅城区东村。1a后,根据叶片伤害程度、新叶增长率、种个体长势、翌春植株恢复状况等综合评价植物对氟化物、硫化物和酸雨组成的大气复合污染的敏感性反应。根据试验结果将供试植物对大气污染的敏感性反应分为3种类型：(1)低敏感性(抗性强),有茶花、红花油茶、傅园榕、小叶榕、桂花、环榕、菩提榕、石笔木、毛黄肉楠、幌伞枫10种。(2)中等敏感(抗性中等),有仪花、格木、吊瓜树、腊肠树、海南红豆、猫尾木、红桂木、灰莉、铁冬青、密花树、白桂木、小叶胭脂、大头茶、复羽叶栾、灰木莲、火焰木、华润楠17种。(3)高度敏感(抗性弱),有铁刀木、观光木、白木香、日本杜英、蓝花楹、蝴蝶树、印度紫檀、柳叶楠、无忧树、海南木莲、乐昌含笑11种。研究结果可为热带、南亚热带地区有类似大气污染的环境进行园林绿化,生态公益林营造提供参考。     

Experience of the Eliava Institute in bacteriophage therapy

<正>The rapid propagation of multidrug resistant bacterial strains is leading to renewed interest in bacteriophage therapy.With challenges in the treatment of bacterial infections,it is essential for people worldwide to understand how alternative approaches,such as bacteriophages,could be used to combat antibiotic resistant bacteria.The Eliava Institute     

Aspergillosis by cryptic Aspergillus species: A case series and review of the literature

BackgroundThe cryptic Aspegillus species are rare, these microorganisms are usually more resistant to common antifungal therapies. Therefore, a correct identification is important when evaluating the impact of such species in aspergillosis.AimsWe aimed to describe the frequency, clinical and microbiological characteristics, and the outcomes of those cases of aspergillosis caused by cryptic species in a tertiary hospital.MethodsWe retrospectively identified all microbiologically documented cases of aspergillosis between January 2013 and December 2018. Definitive species identification of clinically significant isolates was achieved via sequencing methods. The polymerase chain reaction (PCR) products were sequenced, and the results obtained were compared to sequences deposited in GenBank. Antifungal susceptibility testing was performed using the Sensititre® YeastOne® panel.ResultsA total of 679 Aspergillus isolates were recovered from 489 patients, of which 109 were clinically relevant. Ten (9.2%) isolates were identified as cryptic species: Aspergillus arcoverdensis (2), Aspergillus lentulus (2), Aspergillus ellipticus (2), Aspergillus alliaceus (1), Aspergillus nomius (1), Aspergillus tubingensis (1) and Aspergillus montevidensis (1). Most patients already suffered some type of immunosuppression. Half of these patients had required intensive care before the infection showed up, and most of them had a pulmonary infection. Mortality at the 100-day follow-up was 40%. Antifungal susceptibility testing was performed on three of the isolates (A. arcoverdensis, A. tubingensis and A. nomius), which showed high minimum inhibitory concentrations (MIC) for azoles and amphotericin B.ConclusionsThe frequency of cryptic species in our centre was 9.2%. Most patients had some degree of immunosuppression, and the mortality rate was 40%.