Relationships between photosystem II efficiency and photochemical reflectance index under different levels of illumination: comparison among species grown at high- and low elevations through different seasons

This study aimed to propose an approach for orchard trees segmentation using aerial images based on a deep learning convolutional neural network variant, namely the U-net network. The purpose was the automated detection and localization of the canopy of orchard trees under various conditions (i.e., different seasons, different tree ages, different levels of weed coverage). The implemented dataset was composed of images from three different walnut orchards. The achieved variability of the dataset resulted in obtaining images that fell under seven different use cases. The best-trained model achieved 91%, 90%, and 87% accuracy for training, validation, and testing, respectively. The trained model was also tested on never-before-seen orthomosaic images or orchards based on two methods (oversampling and undersampling) in order to tackle issues with out-of-the-field boundary transparent pixels from the image. Even though the training dataset did not contain orthomosaic images, it achieved performance levels that reached up to 99%, demonstrating the robustness of the proposed approach.

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Photosynthesis, photosystem II efficiency and the xanthophyll cycle in the salt-adapted halophyte Atriplex centralasiatica

New Phytologist ◽

10.1046/j.1469-8137.2003.00825.x ◽

2003 ◽

Vol 159 (2) ◽

pp. 479-486 ◽

Cited By ~ 134

Author(s):

Nianwei Qiu ◽

Qingtao Lu ◽

Congming Lu

Keyword(s):

Photosystem Ii ◽

Xanthophyll Cycle ◽

Photosystem Ii Efficiency

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Improving the hydrobiological analysis of activated sludge at the Minsk wastewater treatment facilities

Vodosnabzhenie i sanitarnaia tehnika ◽

10.35776/vst.2021.10.03 ◽

2021 ◽

pp. 26-36

Author(s):

О.С. Дубовик ◽

Р.М. Маркевич ◽

Е.В. Гаврилович ◽

И.А. Гребенчикова ◽

В.В. Иванович

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Point System ◽

Treatment Conditions ◽

Filamentous Microorganisms ◽

Different Seasons ◽

Treatment Facilities ◽

Favorable Conditions ◽

Quantitative Account ◽

Different Levels

На основании накопленного опыта эксплуатации сооружений Минской очистной станции и обзора источников информации определена схема гидробиологического анализа активного ила, приведена форма регистрации результатов проведенного анализа. Для количественного учета нитчатых микроорганизмов разработана собственная пятибалльная система. Для нитчатых микроорганизмов, выявленных в активном иле, на основании анализа литературных данных определены условия, благоприятствующие их массовому развитию. В течение длительного периода времени, включающего разные сезоны года, проведена апробация усовершенствованной методики для мониторинга состояния иловой суспензии очистных сооружений двух площадок станции: классических четырехкоридорных аэротенков-вытеснителей первой площадки и биореакторов с каскадной денитрификацией второй площадки. Определены представители нитчатых микроорганизмов, постоянно обитающие в очистных сооружениях, выявлены доминирующие виды. Проведено сопоставление результатов анализа нитчатых форм и седиментационных характеристик активного ила. Сделаны заключения об особенностях биоценоза аэротенков первой площадки и биореакторов второй площадки, идентичности по видовому составу сообществ нитчатых бактерий, влиянии состава сточных вод и условий их очистки (нагрузка на ил, наличие зон с разным уровнем аэрации) на свойства иловой суспензии. Based on the accumulated experience in operating the Minsk Wastewater Treatment Facilities and a review of information sources, a scheme for the hydrobiological analysis of activated sludge was determined, and a form for recording the results of the analysis was provided. For the quantitative account of filamentous microorganisms, an original five-point system was developed. Based on the literature data analysis, favorable conditions for the mass growth of filamentous microorganisms found in activated sludge were determined. Over a long period of time, including different seasons of the year, the improved methodology was tested for monitoring the state of the sludge suspension at two sites of the treatment facilities: traditional four-line continuous-flow aeration tanks at the first site and bioreactors with cascade denitrification at the second site. The species of filamentous microorganisms, permanently living in wastewater treatment structures, have been identified, and the dominant species have been determined. The results of the analysis of filamentous forms and sedimentation characteristics of activated sludge are compared. Conclusions were made about the features of the biocenosis in the aeration tanks at the first site and in the bioreactors at the second site; about the identity of the species composition of the filamentous bacteria communities, the effect of the wastewater composition and treatment conditions (sludge load, occurrence of zones with different levels of aeration) on the properties of the sludge suspension.

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Light response of D1 turnover and photosystem II efficiency in the seagrassZostera capricorni

Planta ◽

10.1007/bf00620046 ◽

1996 ◽

Vol 198 (3) ◽

pp. 319-323 ◽

Cited By ~ 23

Author(s):

Yvette S. Flanigan ◽

Christa Critchley

Keyword(s):

Photosystem Ii ◽

Light Response ◽

Photosystem Ii Efficiency ◽

D1 Turnover

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Studies of the Biting-habits of African Mosquitos. An Appraisal of Methods employed, with special Reference to the twenty-four-hour Catch

Bulletin of Entomological Research ◽

10.1017/s0007485300026900 ◽

1954 ◽

Vol 45 (1) ◽

pp. 199-242 ◽

Cited By ~ 127

Author(s):

A. J. Haddow

Keyword(s):

Vertical Distribution ◽

Special Reference ◽

Geometric Mean ◽

Seasonal Abundance ◽

Central Tendency ◽

Valuable Method ◽

Different Seasons ◽

Working Out ◽

Different Levels ◽

Biting Behaviour

It is felt that the 24-hour catch presents a valuable method of studying the biting-behaviour of mosquitos in the field, and further that conclusions concerning seasonal abundance, vertical distribution and times of biting-activity must be based on catches of this type if serious errors of interpretation are to be avoided.The time-divisions of the catch should not exceed one hour, and even shorter intervals may be desirable. Timing should be related to the actual times of sunrise and sunset. Where possible, a series of consecutive catches should be carried out, and a shift system must be carefully considered in relation to the particular series projected.Usually the results from different levels above ground should be treated separately in working out biting-cycles, and this may also apply to results from different seasons or different localities. Further, while in some instances the summation of long series of catches seems permissible, in others it is not, and in these detailed analysis of the figures may be necessary before consistent behaviour-patterns become apparent.In cases where a measure of the central tendency is to be employed, the geometric mean as modified by C. B. Williams appears to be the most suitable.

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Reduction in photosystem II efficiency during a virus-controlled Emiliania huxleyi bloom

Marine Ecology Progress Series ◽

10.3354/meps10527 ◽

2014 ◽

Vol 495 ◽

pp. 65-76 ◽

Cited By ~ 13

Author(s):

SA Kimmance ◽

MJ Allen ◽

A Pagarete ◽

J Martínez Martínez ◽

WH Wilson

Keyword(s):

Photosystem Ii ◽

Emiliania Huxleyi ◽

Photosystem Ii Efficiency

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Photosynthesis, quenching of chlorophyll fluorescence and thermal energy dissipation in iron-deficient sugar beet leaves

Functional Plant Biology ◽

10.1071/pp97130 ◽

1998 ◽

Vol 25 (4) ◽

pp. 403 ◽

Cited By ~ 31

Author(s):

Fermín Morales ◽

Anunciación Abadía ◽

Javier Abadía

Keyword(s):

Energy Dissipation ◽

Iron Deficiency ◽

Photosystem Ii ◽

Sugar Beet ◽

Electron Flow ◽

Reaction Centers ◽

O2 Evolution ◽

Photosystem Ii Efficiency ◽

Iron Deficient ◽

Additional Support

In sugar beet (Beta vulgaris L.) iron deficiency decreased not only the photosynthetic rate but also the actual photosystem II efficiency at steady-state photosynthesis. In moderate iron deficiency, the decrease in actual photosystem II efficiency under illumination was related to closure of photosystem II reaction centers, whereas in severe iron deficiency it was associated to decreases of intrinsic photosystem II efficiency. The O2 evolution, on an absorbed light basis, decreased more than the actual photosystem II efficiency, suggesting the presence of a significant fraction of electron transport to molecular oxygen or the existence of some form of cyclic electron flow. Iron-deficient leaves reduced the excess of light absorbed that cannot be used in photosynthesis not only by decreasing absorptance, but also by dissipating a large part of the light absorbed by the photosystem II antenna. This mechanism, that protects the photosystem II reaction centers through the enhancement of energy dissipation, was related to the de-epoxidation of violaxanthin (V) to antheraxanthin (A) and zeaxanthin (Z) in iron-deficient leaves. These data provide additional support for a role of Z+A in photoprotection under conditions of excess photosynthetic light absorption.

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