Determination of the quantitative content of chlorophylls in leaves by reflection spectra using the random forest algorithm

Determining the quantitative content of chlorophylls in plant leaves by their reflection spectra is an important task both in monitoring the state of natural and industrial phytocenoses, and in laboratory studies of normal and pathological processes during plant growth. The use of machine learning methods for these purposes is promising, since these methods allow inferring the relationships between input and output variables (prediction model), and in order to improve the quality of the prediction, a researcher may modify predictors and selects a set of method parameters. Here, we present the results of the implementation and evaluation of the random forest algorithm for predicting the total concentration of chlorophylls a and b from the ref lection spectra of plant leaves in the visible and infrared wavelengths. We used the ref lection spectra for 276 leaf samples from 39 plant species obtained from open sources. 181 samples were from the sycamore maple (Acer pseudoplatanus L.). The ref lection spectrum represented wavelengths from 400 to 2500 nm with a step of 1 nm. The training set consisted of the 85 % of A. pseudoplatanus L. samples, and the performance was evaluated on the remaining 15 % samples of this species (validation sample). Six models based on the random forest algorithm with different predictors were evaluated. The selection of control parameters was performed by cross-checking on five partitions. For the f irst model, the intensity of the ref lection spectra without any transformation was used. Based on the analysis of this model, the optimal ranges of wavelengths for the remaining f ive models were selected. The best results were obtained by models that used a two-point estimation of the derivative of the ref lection spectrum in the visible wavelength range as input data. We compared one of these models (the two-point estimation of the derivative of the ref lection spectrum in the range of 400–800 nm with a step of 1 nm) with the model by other authors (which is based on the functional dependence between two unknown parameters selected by the least squares method and two ref lection coeff icients, the choice of which is described in the article). The comparison of the results of predictions of the model based on the random forest algorithm with the model of other authors was carried out both on the validation sample of maple and on the sample from other plant species. In the f irst case, the predictions of the method based on a random forest had a lower estimate of the standard deviation. In the second case, the predictions of this method had a large error for small values of chlorophyll, while the third-party method had acceptable predictions. The article provides the analysis of the results, as well as recommendations for using this machine learning method to assess the quantitative content of chlorophylls in leaves

ABOUT THE PROJECT ON DEVELOPMENT OF PERSONALLY-ORIENTED ELECTRONIC EDUCATIONAL COURSES

Развитие самостоятельной познавательной деятельности, познавательного интереса, умения самостоятельно планировать, выполнять и контролировать результаты выполненной работы является личностным требованием к результатам освоения образовательных программ основного общего и среднего общего образования. Для этого следует активно внедрять в образовательный процесс дистанционные образовательные технологии и электронное обучение. Цель проекта заключается в разработке электронных учебных курсов, ориентированных на развитие самостоятельной познавательной деятельности обучающихся, учитывающих личностные, метапредметные и предметные требования к результатам освоения обучающимися основных образовательных программ соответствующего уровняThe development of independent cognitive activity, cognitive interest, the ability to independently plan, perform and monitor the results of work performed are personal requirements to the results of mastering educational programs of basic general and secondary general education. For this, distance educational technologies and e learning should be actively introduced into the educational process. The aim of the project is to develop e learning courses aimed at developing independent cognitive activity of students, taking into account personal, meta-subject and subject requirements to the results of mastering the basic educational programs of the appropriate leve

Assessment of the possibility to use the of hot dip galvanizing waste-zinc dust for zinc-rich paints

The chemical and grain-size analysis of zinc dust – waste of hot – dip zinc plating were made. The research results showed that zinc dust is a dispersed waste with particles of mainly circular shape and sizes from 3 to 200 microns, and in chemical composition it mainly meets the requirements of ISO 3549. The presence of lead in the zinc dust composition, which is slightly higher than the acceptable level will be taken into account in the development of zinc-rich paints compositions. Analysis of the results of sieving of zinc dust showed that it contains particles of size £15 µm, which is about 27% of its fractional composition and which can be recommended for the manufacture of zinc-rich paints

Analysis of corrosive properties of zinc-containing coatings based on dispersed waste hot zinc plating

A comparative analysis of the corrosion properties of zinc-containing coatings obtained on the basis of metallic powder zinc and dispersed hot-dip galvanized waste has been carried out. The results of a study of the corrosion resistance of zinc-containing coatings by the electrochemical method and in a salt spray chamber have shown that coatings obtained on the basis of dispersed hot-dip galvanized waste are not inferior in protective properties to coatings based on powder standard zinc

Assessing the Efciency of Detection of Vibrio cholerae Genetic Determinants Through Waterbody Vibrioflora Monitoring System

Objective of the study was to assess the effectiveness of PCR screening of Vibrio cholerae genetic determinants in samples from surface water reservoirs for optimization of the cholera microbiological monitoring system.Materials and methods. The study was carried out as a part of the vibrioflora monitoring in surface water bodies in Irkutsk city. The study design included: 1) PCR screening of V. cholerae genetic determinants in nutrient-enriched (1 % peptone water) samples from surface water reservoirs during the monitoring period (824 samples); 2) studying of the V. cholerae DNA accumulation dynamics applying PCR assay of the samples from surface water reservoirs during cultivation on the enriched media (16 samples in dynamics); 3) experimental study of the detected V. cholerae concentrations in samples from surface water reservoirs. Species-specifc (hlyA, toxR) and serogroup-specifc (wbeT, wbfR) V. cholerae determinants were indicated in PCR with hybridization-fluorescent and electrophoretic detection.Results and discussion. At the frst stage it was found that the proportion of the positive samples through PCR screening (33.9 %) exceeded the percentage of the positive samples in bacteriological examination (19.3 %) (t=6.6; p<0,01). In the assessment of DNA accumulation dynamics, a decrease in the threshold cycle (Ct) by 1.2–5.2 times was recorded, indicating an increase in the V. cholerae concentration and proving the detection of genetic determinants of viable forms during PCR screening. An extended study of PCR-positive but bacteriologically negative samples made it possible to additionally isolate 4 V. cholerae cultures. However, there were no differences in the sensitivity of PCR screening and bacteriological analysis in the experiment with water samples artifcially contaminated with V. cholerae unlike the analysis of the enriched native samples. It can be determined by the metabolism and adaptation peculiarities of the microorganism in different environmental conditions. The results of the integrated study indicate the epidemiological effectiveness of PCR screening which gives grounds to recommend its application in monitoring studies of vibrioflora from environment after preliminary enrichment on liquid nutrient media in the work of federal, territorial, and regional laboratories