scholarly journals How many measurements are needed to estimate accurate daily and annual soil respiration fluxes? Analysis using data from a temperate rainforest

2016 ◽  
Author(s):  
Jorge F. Perez-Quezada ◽  
Carla E. Brito ◽  
Julián Cabezas ◽  
Mauricio Galleguillos ◽  
Juan P. Fuentes ◽  
...  
Keyword(s):  
High Frequency ◽  
Data Series ◽  
Sampling Strategies ◽  
Full Data ◽  
Temperate Rainforest ◽  
Partial Data ◽  
Frequency Sampling ◽  
Using Data ◽  
One Year ◽  
High Frequency Sampling

Abstract. Making accurate estimations of daily and annual Rs fluxes is key for understanding the carbon cycle process and projecting effects of climate change. In this study we used high-frequency sampling (24-measurements per day) of Rs in a temperate rainforest during one year, with the objective of answering the questions of when and how often measurements should be made to obtain accurate estimations of daily and annual Rs. In this aim, we randomly selected data to simulate samplings of 1, 2, 4 or 6 measurements per day (distributed either during the whole day or only during daytime) combined with 4, 6, 12, 26 or 52 measurements per year. Based on the comparison of partial-data series with the full-data series, we estimated the performance of different partial sampling strategies based on bias, precision and accuracy. In the case of annual Rs estimation, we compared the performance of interpolation vs. using non-linear modelling based on soil temperature. The results show that, under our study conditions, sampling twice a day was enough to accurately estimate daily Rs (RMSE 

scholarly journals How many measurements are needed to estimate accurate daily and annual soil respiration fluxes? Analysis using data from a temperate rainforest

2016 ◽  
Vol 13 (24) ◽  
pp. 6599-6609 ◽  
Author(s):  
Jorge F. Perez-Quezada ◽  
Carla E. Brito ◽  
Julián Cabezas ◽  
Mauricio Galleguillos ◽  
Juan P. Fuentes ◽  
...  
Keyword(s):  
Linear Interpolation ◽  
Data Series ◽  
Full Data ◽  
Night Time ◽  
Temperate Rainforest ◽  
Acceptable Error ◽  
Linear Modelling ◽  
Non Linear ◽  
Field Campaigns ◽  
Using Data

Abstract. Making accurate estimations of daily and annual Rs fluxes is key for understanding the carbon cycle process and projecting effects of climate change. In this study we used high-frequency sampling (24 measurements per day) of Rs in a temperate rainforest during 1 year, with the objective of answering the questions of when and how often measurements should be made to obtain accurate estimations of daily and annual Rs. We randomly selected data to simulate samplings of 1, 2, 4 or 6 measurements per day (distributed either during the whole day or only during daytime), combined with 4, 6, 12, 26 or 52 measurements per year. Based on the comparison of partial-data series with the full-data series, we estimated the performance of different partial sampling strategies based on bias, precision and accuracy. In the case of annual Rs estimation, we compared the performance of interpolation vs. using non-linear modelling based on soil temperature. The results show that, under our study conditions, sampling twice a day was enough to accurately estimate daily Rs (RMSE  <  10 % of average daily flux), even if both measurements were done during daytime. The highest reduction in RMSE for the estimation of annual Rs was achieved when increasing from four to six measurements per year, but reductions were still relevant when further increasing the frequency of sampling. We found that increasing the number of field campaigns was more effective than increasing the number of measurements per day, provided a minimum of two measurements per day was used. Including night-time measurements significantly reduced the bias and was relevant in reducing the number of field campaigns when a lower level of acceptable error (RMSE  <  5 %) was established. Using non-linear modelling instead of linear interpolation did improve the estimation of annual Rs, but not as expected. In conclusion, given that most of the studies of Rs use manual sampling techniques and apply only one measurement per day, we suggest performing an intensive sampling at the beginning of the study to determine minimum daily and annual frequencies of sampling.

Temporal Properties Study of Ocular Wave Aberrations with High Frequency Sampling

2014 ◽  
Vol 34 (7) ◽  
pp. 0733001
Author(s):  
郑贤良 Zheng Xianliang ◽  
刘瑞雪 Liu Ruixue ◽  
夏明亮 Xia Mingliang ◽  
李大禹 Li Dayu ◽  
宣丽 Xuan Li
Keyword(s):  
High Frequency ◽  
Temporal Properties ◽  
Frequency Sampling ◽  
High Frequency Sampling

Multipoint High-Frequency Sampling System to Gain Deeper Insights on the Fate of Nitrate in Artificially Drained Fields

2020 ◽  
Vol 146 (1) ◽  
pp. 06019012 ◽  
Author(s):  
Wenlong Liu ◽  
Bryan Maxwell ◽  
François Birgand ◽  
Mohamed Youssef ◽  
George Chescheir ◽  
...  
Keyword(s):  
High Frequency ◽  
Sampling System ◽  
Frequency Sampling ◽  
High Frequency Sampling

scholarly journals Cohort profile: molecular signature in pregnancy (MSP): longitudinal high-frequency sampling to characterise cross-omic trajectories in pregnancy in a resource-constrained setting

BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e041631
Author(s):  
Tobias Brummaier ◽  
Basirudeen Syed Ahamed Kabeer ◽  
Pornpimon Wilaisrisak ◽  
Mupawjay Pimanpanarak ◽  
Aye Kyi Win ◽  
...  
Keyword(s):  
Preterm Birth ◽  
Pregnant Women ◽  
Pregnancy Outcomes ◽  
High Frequency ◽  
Molecular Signature ◽  
Resource Constrained ◽  
Targeted Interventions ◽  
Frequency Sampling ◽  
High Frequency Sampling ◽  
In Pregnancy

PurposeA successful pregnancy relies on the interplay of various biological systems. Deviations from the norm within a system or intersystemic interactions may result in pregnancy-associated complications and adverse pregnancy outcomes. Systems biology approaches provide an avenue of unbiased, in-depth phenotyping in health and disease. The molecular signature in pregnancy (MSP) cohort was established to characterise longitudinal, cross-omic trajectories in pregnant women from a resource constrained setting. Downstream analysis will focus on characterising physiological perturbations in uneventful pregnancies, pregnancy-associated complications and adverse outcomes.ParticipantsFirst trimester pregnant women of Karen or Burman ethnicity were followed prospectively throughout pregnancy, at delivery and until 3 months post partum. Serial high-frequency sampling to assess whole blood transcriptomics and microbiome composition of the gut, vagina and oral cavity, in conjunction with assessment of gene expression and microbial colonisation of gestational tissue, was done for all cohort participants.Findings to date381 women with live born singletons averaged 16 (IQR 15–18) antenatal visits (13 094 biological samples were collected). At 5% (19/381) the preterm birth rate was low. Other adverse events such as maternal febrile illness 7.1% (27/381), gestational diabetes 13.1% (50/381), maternal anaemia 16.3% (62/381), maternal underweight 19.2% (73/381) and a neonate born small for gestational age 20.2% (77/381) were more often observed than preterm birth.Future plansResults from the MSP cohort will enable in-depth characterisation of cross-omic molecular trajectories in pregnancies from a population in a resource-constrained setting. Moreover, pregnancy-associated complications and unfavourable pregnancy outcomes will be investigated at the same granular level, with a particular focus on population relevant needs such as effect of tropical infections on pregnancy. More detailed knowledge on multiomic perturbations will ideally result in the development of diagnostic tools and ultimately lead to targeted interventions that may disproportionally benefit pregnant women from this resource-limited population.Trial registration numberNCT02797327.

High frequency sampling by means of miniaturized reversed plasmapheresis in the analysis of episodic hormone secretion

1986 ◽  
Vol 113 (1_Suppl) ◽  
pp. S201
Author(s):  
A. GÖHRING ◽  
A. PRECHEL ◽  
A. KRAUSE ◽  
T.O.F. WAGNER ◽  
A. VON ZUR MÜHLEN
Keyword(s):  
High Frequency ◽  
Hormone Secretion ◽  
Frequency Sampling ◽  
High Frequency Sampling
Sign in / Sign up

Export Citation Format

Share Document