scholarly journals Retrieval of Solar-induced Chlorophyll Fluorescence from TanSat Measurements: Comparison of SIF between TanSat and OCO-2

2021 ◽  
Author(s):  
Lu Yao ◽  
Yi Liu ◽  
Dongxu Yang ◽  
Zhaonan Cai ◽  
Chao Lin ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Data Quality ◽  
Comparable Data ◽  
Plant Leaves ◽  
Quality Testing ◽  
One Year ◽  
The Relationship ◽  
Global Carbon ◽  
Strong Linear Relationship ◽  
Spatiotemporal Consistency

Abstract. Solar-induced chlorophyll fluorescence (SIF) is emitted during photosynthesis in plant leaves. It constitutes a small additional offset to reflected radiance and can be observed by sensitive instruments. The Chinese global carbon dioxide monitoring satellite (TanSat), as its mission, acquires greenhouse gas column density. The advanced technical characteristics of the hyper-spectrum grating spectrometer (ACGS) onboard TanSat enable SIF retrieval from space observations in the O2-A band. In this study, one-year SIF data was processed from Orbiting Carbon Observatory-2 (OCO-2) and TanSat using a physical-based algorithm. A comparison between the SIF retrieved from OCO-2 and its official product shows their strong linear relationship (R2 > 0.85) and suggests the reliability of the algorithm. The global distribution showed that the SIF retrieved from the two satellites shared the same spatial pattern for all seasons with the grided SIF difference less than 0.3 W m−2 μm−1 sr−1, and they also agreed with the official OCO-2 SIF product. The retrieval uncertainty of seasonal-grided TanSat SIF is less than 0.03 W m−2 μm−1 sr−1 whereas the uncertainty of each sounding ranges from 0.1 to 0.6 W m−2 μm−1 sr−1. The relationship between SIF and terrestrial gross primary productivity was also estimated for data quality testing. The spatiotemporal consistency between TanSat and OCO-2 and their comparable data quality make the comprehensive usage of the two mission products possible. Data supplemented by TanSat observations are expected to contribute to the development of global SIF maps with more spatiotemporal detail, which will advance global research on vegetation photosynthesis.

Bankruptcy Model Construction and its Limitation in Input Data Quality

2019 ◽  
Vol 10 (2) ◽  
pp. 117-125
Author(s):  
Dana Kubíčková ◽  
◽  
Vladimír Nulíček ◽  
Keyword(s):  
Data Quality ◽  
Normal Distribution ◽  
Input Data ◽  
Model Construction ◽  
The Third ◽  
Third Stage ◽  
Discriminant Analyses ◽  
One Year ◽  
The University ◽  
Multivariate Discriminant

The aim of the research project solved at the University of Finance and administration is to construct a new bankruptcy model. The intention is to use data of the firms that have to cease their activities due to bankruptcy. The most common method for bankruptcy model construction is multivariate discriminant analyses (MDA). It allows to derive the indicators most sensitive to the future companies’ failure as a parts of the bankruptcy model. One of the assumptions for using the MDA method and reassuring the reliable results is the normal distribution and independence of the input data. The results of verification of this assumption as the third stage of the project are presented in this article. We have revealed that this assumption is met only in a few selected indicators. Better results were achieved in the indicators in the set of prosperous companies and one year prior the failure. The selected indicators intended for the bankruptcy model construction thus cannot be considered as suitable for using the MDA method.

scholarly journals Evaluating the diagnostic test accuracy of molecular xenomonitoring methods for characterising community burden of lymphatic filariasis

2021 ◽  
Author(s):  
Joseph Pryce ◽  
Lisa J Reimer
Keyword(s):  
Systematic Review ◽  
Lymphatic Filariasis ◽  
Meta Analysis ◽  
Test Accuracy ◽  
Sample Sizes ◽  
Pathogen Dna ◽  
Low Sensitivity ◽  
The Relationship ◽  
Molecular Xenomonitoring ◽  
Strong Linear Relationship

Abstract Background Molecular xenomonitoring (MX), the detection of pathogen DNA in mosquitoes, is a recommended approach to support lymphatic filariasis (LF) elimination efforts. Potential roles of MX include detecting presence of LF in communities and quantifying progress towards elimination of the disease. However, the relationship between MX results and human prevalence is poorly understood. Methods :We conducted a systematic review and meta-analysis from all previously conducted studies that reported the prevalence of filarial DNA in wild-caught mosquitoes (MX rate) and the corresponding prevalence of microfilaria (mf) in humans. We calculated a pooled estimate of MX sensitivity for detecting positive communities at a range of mf prevalence values and mosquito sample sizes. We conducted a linear regression to evaluate the relationship between mf prevalence and MX rate. Results We identified 24 studies comprising 144 study communities. MX had an overall sensitivity of 98.3% (95% CI 41.5, 99.9%) and identified 28 positive communities that were negative in the mf survey. Low sensitivity in some studies was attributed to small mosquito sample sizes (<1,000) and very low mf prevalence (<0.25%). Human mf prevalence and mass drug administration status accounted for approximately half of the variation in MX rate (R 2 = 0.49, p<0.001). Data from longitudinal studies showed that, within a given study area, there is a strong linear relationship between MX rate and mf prevalence (R 2 = 0.78, p < 0.001). Conclusion MX shows clear potential as tool for detecting communities where LF is present and as a predictor of human mf prevalence.

scholarly journals CO2 dynamics and heterogeneity in a cave atmosphere: role of ventilation patterns and airflow pathways

2021 ◽  
Author(s):  
Lovel Kukuljan ◽  
Franci Gabrovšek ◽  
Matthew D. Covington ◽  
Vanessa E. Johnston
Keyword(s):  
Temporal Variations ◽  
Observation Point ◽  
Spatially Distributed ◽  
Combined Action ◽  
Karst Systems ◽  
The Relationship ◽  
Co2 Dynamics ◽  
Global Carbon

AbstractUnderstanding the dynamics and distribution of CO2 in the subsurface atmosphere of carbonate karst massifs provides important insights into dissolution and precipitation processes, the role of karst systems in the global carbon cycle, and the use of speleothems for paleoclimate reconstructions. We discuss long-term microclimatic observations in a passage of Postojna Cave, Slovenia, focusing on high spatial and temporal variations of pCO2. We show (1) that the airflow through the massif is determined by the combined action of the chimney effect and external winds and (2) that the relationship between the direction of the airflow, the geometry of the airflow pathways, and the position of the observation point explains the observed variations of pCO2. Namely, in the terminal chamber of the passage, the pCO2 is low and uniform during updraft, when outside air flows to the site through a system of large open galleries. When the airflow reverses direction to downdraft, the chamber is fed by inlets with diverse flow rates and pCO2, which enter via small conduits and fractures embedded in a CO2-rich vadose zone. If the spatial distribution of inlets and outlets produces minimal mixing between low and high pCO2 inflows, high and persistent gradients in pCO2 are formed. Such is the case in the chamber, where vertical gradients of up to 1000 ppm/m are observed during downdraft. The results presented in this work provide new insights into the dynamics and composition of the subsurface atmosphere and demonstrate the importance of long-term and spatially distributed observations.

scholarly journals Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kuang-Yu Chang ◽  
William J. Riley ◽  
Sara H. Knox ◽  
Robert B. Jackson ◽  
Gavin McNicol ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Spatial Scales ◽  
Biogeochemical Model ◽  
Spatial And Temporal Variability ◽  
Biogeochemical Models ◽  
Model Parameterization ◽  
Machine Learning Model ◽  
Meta Analyses ◽  
The Relationship ◽  
Global Carbon

AbstractWetland methane (CH4) emissions ($${F}_{{{CH}}_{4}}$$ F C H 4 ) are important in global carbon budgets and climate change assessments. Currently, $${F}_{{{CH}}_{4}}$$ F C H 4 projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent $${F}_{{{CH}}_{4}}$$ F C H 4 temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that $${F}_{{{CH}}_{4}}$$ F C H 4 are often controlled by factors beyond temperature. Here, we evaluate the relationship between $${F}_{{{CH}}_{4}}$$ F C H 4 and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between $${F}_{{{CH}}_{4}}$$ F C H 4 and temperature, suggesting larger $${F}_{{{CH}}_{4}}$$ F C H 4 sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.

The Relationship between the Binding of Dicyclohexylcarbodiimide and Quenching of Chlorophyll Fluorescence in the Light-Harvesting Proteins of Photosystem II†

Biochemistry ◽  
1998 ◽  
Vol 37 (33) ◽  
pp. 11586-11591 ◽  
Author(s):  
Alexander V. Ruban ◽  
Paolo Pesaresi ◽  
Ulrich Wacker ◽  
Klaus-Dieter J. Irrgang ◽  
Roberto Bassi ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
The Relationship

Dresden commemorative meetings: Vladimir Scherbachev — Nikolay Medtner

2020 ◽  
pp. 25-39
Author(s):  
Р.Н. Слонимская
Keyword(s):  
Musical Culture ◽  
Russian Culture ◽  
Opera House ◽  
Boris Godunov ◽  
One Year ◽  
Relationship Of ◽  
The Relationship

В статье рассматриваются взаимоотношения выдающихся музыкальных деятелей русской культуры Владимира Владимировича Щербачёва и Николая Карловича Метнера. Фактический материал анализируется на основе писем Щербачёва к жене, Марии Илларионовне, написанных в период командировки 1922-1923 годов в Пильниц под Дрезденом. В письмах раскрывается атмосфера музыкальной культуры Германии этого периода (в том числе постановка в Дрезденской опере Бориса Годунова Модеста Петровича Мусоргского). Подробно описывается процесс работы Щербачёва над партитурой монументального симфонического полотна Второй симфонии на стихи Александра Блока и приводится мнение Метнера о ней. Раскрываются музыкально-эстетические позиции Щербачёва и Метнера в отношении разных сторон техники сочинения, педагогики, исполнительского искусства. Одна из ключевых проблем сохранение традиции и радикальное новаторство, вызывавшее у Метнера весьма сложную реакцию. В целом, письма музыкантов дают возможность воссоздать живой и органичный облик двух композиторов разных творческих ориентаций, но искренне переживающих за музыкальное искусство. В конце статьи представлена роль Щербачёва в становлении ленинградской школы композиции. The article considers the relationship of outstanding music figures of the Russian culture VladimirV.Scherbachev and NikolayK.Medtner. The analyzed factual material is based on Scherbachevs letters to his wife Maria Illarionovna, written during a one-year trip to Pilnitz on the Elbe near Dresden 19221923. The letters reveal the atmosphere of musical culture of Germany of this period (including the production of Boris Godunov by Mussorgsky in the Dresden opera house). The author gives a detailed description of the process of Scherbachevs work on the score of the monumental symphonic canvas the Second Symphony on the poems by A.Blok, and Medtners opinion about it. In general, the letters of the two musicians give us an opportunity to recreate living and organic image of the two composers possessing different creative bearings, but sincerely worried about the music art.

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