scholarly journals Comparison of Two PARAFAC Models of Dissolved Organic Matter Fluorescence for a Mid-Atlantic Forested Watershed in the USA

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Shatrughan Singh ◽  
Shreeram Inamdar ◽  
Durelle Scott
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Specific Model ◽  
Forested Watershed ◽  
Strongly Correlated ◽  
Site Specific ◽  
The Usa ◽  
Study Sites ◽  
Model Components ◽  
A Site

The composition of dissolved organic matter (DOM) in a mid-Atlantic forested watershed was evaluated using two fluorescence models—one based on previously validated model (Cory and McKnight, 2005) and the other developed specifically for our study site. DOM samples for the models were collected from multiple watershed sources over a two-year period. The previously validated parallel factor analysis (PARAFAC) model had 13 DOM components whereas our site-specific model yielded six distinct components including two terrestrial humic-like, two microbial-derived humic-like, and two protein-like components. The humic-like components were highest in surficial watershed sources and decreased from soil water to groundwater whereas the protein-like components were highest for groundwater sources. Discriminant analyses indicated that our site-specific model was more sensitive to subtle differences in DOM and the sum of the humic- and protein-like constituents yielded more pronounced differences among watershed sources as opposed to the prevalidated model. Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) concentrations and selected DOM metrics were also more strongly correlated with the site-specific model components. These results suggest that while the pre-validated model may capture broader trends in DOM composition and allow comparisons with other study sites, a site-specific model will be more sensitive for characterizing within-site differences in DOM.

Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

2012 ◽  
Vol 117 (G3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Robert G. M. Spencer ◽  
Kenna D. Butler ◽  
George R. Aiken
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Dissolved Organic Carbon ◽  
Chromophoric Dissolved Organic Matter ◽  
The Usa

scholarly journals Dissolved organic matter export from a forested watershed during Hurricane Irene

2012 ◽  
Vol 39 (18) ◽  
Author(s):  
Byungman Yoon ◽  
Peter A. Raymond
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forested Watershed ◽  
Hurricane Irene

scholarly journals Tracing the transport of colored dissolved organic matter in water masses of the Southern Beaufort Sea: relationship with hydrographic characteristics

2012 ◽  
Vol 9 (3) ◽  
pp. 925-940 ◽  
Author(s):  
A. Matsuoka ◽  
A. Bricaud ◽  
R. Benner ◽  
J. Para ◽  
R. Sempéré ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Layer ◽  
Dissolved Organic Matter ◽  
Heat Budget ◽  
Ocean Color ◽  
Beaufort Sea ◽  
The Arctic ◽  
Strongly Correlated ◽  
Colored Dissolved Organic Matter ◽  
Color Data

Abstract. Light absorption by colored dissolved organic matter (CDOM) [aCDOM(λ)] plays an important role in the heat budget of the Arctic Ocean, contributing to the recent decline in sea ice, as well as in biogeochemical processes. We investigated aCDOM(λ) in the Southern Beaufort Sea where a significant amount of CDOM is delivered by the Mackenzie River. In the surface layer, aCDOM(440) showed a strong and negative correlation with salinity, indicating strong river influence and conservative transport in the river plume. Below the mixed layer, a weak but positive correlation between aCDOM(440) and salinity was observed above the upper halocline, resulting from the effect of removal of CDOM due to brine rejection and lateral intrusion of Pacific summer waters into these layers. In contrast, the relationship was negative in the upper and the lower haloclines, suggesting these waters originated from Arctic coastal waters. DOC concentrations in the surface layer were strongly correlated with aCDOM(440) (r2 = 0.97), suggesting that this value can be estimated in this area, using aCDOM(440) that is retrieved using satellite ocean color data. Implications for estimation of DOC concentrations in surface waters using ocean color remote sensing are discussed.

Dissolved organic matter transformation in the hyporheic zone of a small lowland river

2010 ◽  
Vol 39 (2) ◽  
Author(s):  
Piotr Zieliński ◽  
Elżbieta Jekatierynczuk-Rudczyk
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Small Scale ◽  
Lowland River ◽  
Organic Matter Transformation ◽  
Doc Concentration ◽  
Different Depths ◽  
Study Sites

Dissolved organic matter transformation in the hyporheic zone of a small lowland riverThe objective of this study was to examine dissolved organic carbon (DOC) concentration and specific ultraviolet absorbance (SUVA) changes in porewaters that occur over a small scale (cm) in the hyporheic zone (HZ) of a lowland stream in the Knyszynska Forest in northeast Poland. Hyporheic zone porewaters were sampled at different depths of 10, 30, 50, 70 cm at two study sites with different sediment material. The results showed significant differences in DOC concentrations between the upper and lower stream HZ. The current results indicate that small lowland sediments provide both a source and a sink of DOC for stream water, depending on the river course. The higher DOC level observed in the hyporheic zone suggests that porewater can be an autonomic site of biogeochemical changes of dissolved organic matter, which is very clear in the SUVA fluctuations.

Variations in the composition and adsorption behavior of dissolved organic matter at a small, forested watershed

2004 ◽  
Vol 67 (1) ◽  
pp. 39-56 ◽  
Author(s):  
Monique Meier ◽  
Yu-Ping Chin ◽  
Patricia Maurice
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Adsorption Behavior ◽  
Forested Watershed

scholarly journals A site specific model and analysis of the neutral somatic mutation rate in whole-genome cancer data

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Johanna Bertl ◽  
Qianyun Guo ◽  
Malene Juul ◽  
Søren Besenbacher ◽  
Morten Muhlig Nielsen ◽  
...  
Keyword(s):  
Somatic Mutation ◽  
Mutation Rate ◽  
Specific Model ◽  
Whole Genome ◽  
Site Specific ◽  
Cancer Data ◽  
A Site

scholarly journals Simulating streamflow and dissolved organic matter export from a forested watershed

2012 ◽  
Vol 48 (5) ◽  
Author(s):  
Na Xu ◽  
James E. Saiers ◽  
Henry F. Wilson ◽  
Peter A. Raymond
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forested Watershed

scholarly journals A Plasma 5-Marker Host Biosignature Identifies Tuberculosis in High and Low Endemic Countries

2021 ◽  
Vol 12 ◽  
Author(s):  
Bih H. Chendi ◽  
Candice I. Snyders ◽  
Kristian Tonby ◽  
Synne Jenum ◽  
Martin Kidd ◽  
...  
Keyword(s):  
South African ◽  
Respiratory Diseases ◽  
High Accuracy ◽  
University Hospital ◽  
Site Specific ◽  
Diagnostic Potential ◽  
Single Marker ◽  
Study Sites ◽  
A Site ◽  
Study Participants

Background: Several host inflammatory markers have been proposed as biomarkers for diagnosis and treatment response in Tuberculosis (TB), but few studies compare their utility in different demographic, ethnic, and TB endemic settings.Methods: Fifty-four host biomarkers were evaluated in plasma samples obtained from presumed TB cases recruited at the Oslo University Hospital in Norway, and a health center in Cape Town, South Africa. Based on clinical and laboratory assessments, participants were classified as having TB or other respiratory diseases (ORD). The concentrations of biomarkers were analyzed using the Luminex multiplex platform.Results: Out of 185 study participants from both study sites, 107 (58%) had TB, and 78 (42%) ORD. Multiple host markers showed diagnostic potential in both the Norwegian and South African cohorts, with I-309 as the most accurate single marker irrespective of geographical setting. Although study site-specific biosignatures had high accuracy for TB, a site-independent 5-marker biosignature (G-CSF, C3b/iC3b, procalcitonin, IP-10, PDGF-BB) was identified diagnosing TB with a sensitivity of 72.7% (95% CI, 49.8–82.3) and specificity of 90.5% (95% CI, 69.6–98.8) irrespective of geographical site.Conclusion: A 5-marker host plasma biosignature has diagnostic potential for TB disease irrespective of TB setting and should be further explored in larger cohorts.

scholarly journals Effect of Dissolved Organic Matter on Stream Water Quality in Forested Watershed

1995 ◽  
Vol 39 ◽  
pp. 223-228
Author(s):  
Seiji Hayashi ◽  
Koki Goto ◽  
Ryuich Sudo
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Stream Water ◽  
Forested Watershed ◽  
Stream Water Quality

scholarly journals Modeling site-specific nucleotide biases affecting Himar1 transposon insertion frequencies in TnSeq datasets

2021 ◽  
Author(s):  
Sanjeevani Choudhery ◽  
A Jacob Brown ◽  
Chidiebere D Akusobi ◽  
Eric J. Rubin ◽  
Christopher M Sassetti ◽  
...  
Keyword(s):  
Markov Models ◽  
A Priori ◽  
Growth Conditions ◽  
Specific Model ◽  
Site Specific ◽  
Transposon Insertion ◽  
Local Sequence ◽  
A Site ◽  
Analytical Approaches ◽  
Insertion Mutants

In bacterial TnSeq experiments, a library of transposons insertion mutants is generated, selected under various growth conditions, and sequenced to determine the profile of insertions at different sites in the genome, from which the fitness of mutant strains can be inferred. The widely used Himar1 transposon is known to be restricted to insertions at TA dinucleotides, but otherwise, few site-specific biases have been identified. As a result, most analytical approaches assume that insertion counts are expected a priori to be randomly distributed among TA sites in non-essential regions. However, recent analyses of independent Himar1 Tn libraries in M. tuberculosis have identified a local sequence pattern that is non-permissive for Himar1 insertion. This suggests there are site-specific biases that affect the frequency of insertions of the Himar1 transposon at different TA sites. In this paper, we use statistical and machine learning models to characterize patterns in the nucleotides surrounding TA sites associated with high and low insertion counts. We not only affirm that the previously discovered non-permissive pattern (CG)GnTAnC(CG) suppresses insertions, but conversely show that an A in the -3 position or T in the +3 position from the TA site encourages them. We demonstrate that these insertion preferences exist in Himar1 TnSeq datasets other than M. tuberculosis, including mycobacterial and non-mycobacterial species. We build predictive models of Himar1 insertion preferences as a function of surrounding nucleotides. The final predictive model explains about half of the variance in insertion counts, presuming the rest comes from stochastic variability between libraries or due to sampling differences during sequencing. Based on this model, we present a new method, called the TTN-Fitness method, to improve the identification of conditionally essential genes or genetic interactions, i.e., to better distinguish true biological fitness effects by comparing the observed counts to expected counts using a site-specific model of insertion preferences. Compared to previous methods like Hidden Markov Models, the TTN-Fitness method is able to classify the essentiality of many small genes (with few TA sites) that were previously characterized as Uncertain.

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