scholarly journals Concentration-discharge relationships vary among hydrological events, reflecting differences in event characteristics

2020 ◽  
Author(s):  
Julia Knapp ◽  
Jana von Freyberg ◽  
Björn Studer ◽  
Leonie Kiewiet ◽  
James Kirchner
Keyword(s):  
Trace Metals ◽  
Major Ions ◽  
Low Frequency ◽  
Solute Concentration ◽  
Biologically Active ◽  
Storm Events ◽  
Event Scale ◽  
Wide Range ◽  
Insight Into

<p>Studying the response of streamwater chemistry to changes in discharge can improve our understanding of how catchments store and release water and solutes. Previous studies have determined concentration-discharge (cQ) relationships from long-term, low-frequency data for many different solutes. These analyses, however, provide little insight into the coupling of solute concentrations and flow during individual hydrologic events. Although intra-event cQ relationships have been determined for selected solutes and storm events, they have rarely been investigated across a wide range of solutes and over extended periods of time. Thus, little is known about how intra-event and longer-term cQ relationships may differ, potentially providing different perspectives on processes regulating transport through the landscape.</p><p>We present cQ relationships of 14 different solutes, ranging from major ions to trace metals, as well as electrical conductivity, in the Swiss Erlenbach catchment (0.7 km<sup>2</sup>). From a 2-year time series of sub-hourly solute concentration measurements, we determined long-term cQ relationships for each solute. We compared these to cQ relationships spanning the hydrograph recessions of 30 individual events. Solutes sharing the same dominant water sources exhibited similar behavior. Groundwater-sourced solutes exhibited dilution patterns, and their long-term cQ behavior was representative of their cQ behavior during hydrologic events. Other solutes, however, exhibited highly variable cQ behavior from one event to the next, and very different cQ patterns at intra-event and longer-term time scales. This was particularly true for trace metals as well as atmospherically derived and/or biologically active solutes. Most of the observed event-to-event variability in cQ behavior could be explained by factors such as catchment wetness, season, event size, input concentrations, and event-water contributions. These relationships help to clarify how the release of solutes depends on their catchment sources and pathways. Our analysis thus provides insight into controls on solute variations at the hydrologic event scale.</p>

scholarly journals Concentration-discharge relationships vary among hydrological events, reflecting differences in event characteristics

2020 ◽  
Author(s):  
Julia L. A. Knapp ◽  
Jana von Freyberg ◽  
Bjørn Studer ◽  
Leonie Kiewiet ◽  
James W. Kirchner
Keyword(s):  
Trace Metals ◽  
Major Ions ◽  
Low Frequency ◽  
Solute Concentration ◽  
Biologically Active ◽  
Concentration Data ◽  
Event Scale ◽  
Wide Range ◽  
Insight Into

Abstract. Studying the response of streamwater chemistry to changes in discharge can provide valuable insights into how catchments store and release water and solutes. Previous studies have determined concentration-discharge (cQ) relationships from long-term, low-frequency data of a wide range of solutes. These analyses, however, provide little insight into the coupling of solute concentrations and flow during individual hydrologic events. Event-scale cQ relationships have rarely been investigated across a wide range of solutes and over extended periods of time, and thus little is known about differences and similarities between event-scale and long-term cQ relationships. Differences between event-scale and long-term cQ behavior may provide useful information about the processes regulating their transport through the landscape. Here we analyze cQ relationships of 14 different solutes, ranging from major ions to trace metals, as well as electrical conductivity, in the Swiss Erlenbach catchment. From a 2-year time series of sub-hourly solute concentration data we determined long-term cQ relationships for each solute and compared them to cQ relationships of 30 individual events. The long-term cQ behavior of groundwater-sourced solutes was representative of their cQ behavior during hydrologic events. Other solutes, however, exhibited very different cQ patterns at the event and long-term scale. This was particularly true for trace metals as well as atmospheric and/or biologically active solutes, many of which exhibited highly variable cQ behavior from one event to the next. Most of this inter-event variability in cQ behavior can be explained by factors such as catchment wetness, season, event size, input concentrations, and event-water contributions. We present an overview of the processes regulating different groups of solutes, depending on their origin in and pathways through the catchment. Our analysis thus provides insight into controls on solute variations at the hydrologic event scale.

scholarly journals Concentration–discharge relationships vary among hydrological events, reflecting differences in event characteristics

2020 ◽  
Vol 24 (5) ◽  
pp. 2561-2576 ◽  
Author(s):  
Julia L. A. Knapp ◽  
Jana von Freyberg ◽  
Bjørn Studer ◽  
Leonie Kiewiet ◽  
James W. Kirchner
Keyword(s):  
Trace Metals ◽  
Major Ions ◽  
Low Frequency ◽  
Solute Concentration ◽  
Biologically Active ◽  
Concentration Data ◽  
Event Scale ◽  
Wide Range ◽  
Insight Into

Abstract. Studying the response of streamwater chemistry to changes in discharge can provide valuable insights into how catchments store and release water and solutes. Previous studies have determined concentration–discharge (cQ) relationships from long-term, low-frequency data of a wide range of solutes. These analyses, however, provide little insight into the coupling of solute concentrations and flow during individual hydrologic events. Event-scale cQ relationships have rarely been investigated across a wide range of solutes and over extended periods of time, and thus little is known about differences and similarities between event-scale and long-term cQ relationships. Differences between event-scale and long-term cQ behavior may provide useful information about the processes regulating their transport through the landscape. Here we analyze cQ relationships of 14 different solutes, ranging from major ions to trace metals, as well as electrical conductivity, in the Swiss Erlenbach catchment. From a 2-year time series of sub-hourly solute concentration data, we determined 2-year cQ relationships for each solute and compared them to cQ relationships of 30 individual events. The 2-year cQ behavior of groundwater-sourced solutes was representative of their cQ behavior during hydrologic events. Other solutes, however, exhibited very different cQ patterns at the event scale and across 2 consecutive years. This was particularly true for trace metals and atmospheric and/or biologically active solutes, many of which exhibited highly variable cQ behavior from one event to the next. Most of this inter-event variability in cQ behavior could be explained by factors such as catchment wetness, season, event size, input concentrations, and event-water contributions. We present an overview of the processes regulating different groups of solutes, depending on their origin in and pathways through the catchment. Our analysis thus provides insight into controls on solute variations at the hydrologic event scale.

scholarly journals Closing up onto our sun: solar imaging

2020 ◽  
Vol 240 ◽  
pp. 07011
Author(s):  
Kushagra Shrivastava ◽  
Keith Wen Kai Chia ◽  
Kang Jun Wong ◽  
Alfred Yong Liang Tan ◽  
Hwee Tiang Ning
Keyword(s):  
Solar Activity ◽  
The Sun ◽  
Research Needs ◽  
Large Numbers ◽  
Wide Range ◽  
Future Science ◽  
Insight Into ◽  
Term Data ◽  
Made In

Solar activity research provides insight into the Sun’s past, future (Science Daily, 2018). The solar activity includes observations of large numbers of intense sunspots, flares, and other phenomena; and demands a wide range of techniques and measurements on the observations. This research needs long term data collection before critical analyses can occur, to generate meaningful learning and knowledge. In this project, we will use solar imaging to make observations of solar activity, and take our baby steps to make contributions in citizen science. Observations will be made in 3 wavelengths to gain a more thorough analysis by looking at different perspectives of the Sun, namely H-Alpha, Calcium-K, and white light.

scholarly journals Devising a new filtration method and proof of self-similarity of electromyograms

2021 ◽  
Vol 4 (9(112)) ◽  
pp. 15-22
Author(s):  
Gennady Chuiko ◽  
Olga Dvornik ◽  
Yevhen Darnapuk ◽  
Yevgen Baganov
Keyword(s):  
Low Frequency ◽  
Fractal Dimensionality ◽  
Data Matrix ◽  
Self Similarity ◽  
Short Term ◽  
Poincaré Plot ◽  
Filtration Method ◽  
Wide Range ◽  
Jacobi Rotation

The main attention is paid to the analysis of electromyogram (EMG) signals using Poincaré plots (PP). It was established that the shapes of the plots are related to the diagnoses of patients. To study the fractal dimensionality of the PP, the method of counting the coverage figures was used. The PP filtration was carried out with the help of Haar wavelets. The self-similarity of Poincaré plots for the studied electromyograms was established, and the law of scaling was used in a fairly wide range of coverage figures. Thus, the entire Poincaré plot is statistically similar to its own parts. The fractal dimensionalities of the PP of the studied electromyograms belong to the range from 1.36 to 1.48. This, as well as the values of indicators of Hurst exponent of Poincaré plots for electromyograms that exceed the critical value of 0.5, indicate the relative stability of sequences. The algorithm of the filtration method proposed in this research involves only two simple stages: Conversion of the input data matrix for the PP using the Jacobi rotation. Decimation of both columns of the resulting matrix (the so-called "lazy wavelet-transformation", or double downsampling). The algorithm is simple to program and requires less machine time than existing filters for the PP. Filtered Poincaré plots have several advantages over unfiltered ones. They do not contain extra points, allow direct visualization of short-term and long-term variability of a signal. In addition, filtered PPs retain both the shape of their prototypes and their fractal dimensionality and variability descriptors. The detected features of electromyograms of healthy patients with characteristic low-frequency signal fluctuations can be used to make clinical decisions.

Interaction between biomass-burning aerosol and clouds under different climate/weather regimes

2020 ◽  
Author(s):  
Azusa Takeishi ◽  
Chien Wang
Keyword(s):  
Biomass Burning ◽  
Extended Period ◽  
Climate Regime ◽  
Maritime Continent ◽  
Convective Clouds ◽  
Wide Range ◽  
Biomass Burning Aerosol ◽  
Biomass Burning Particles ◽  
Insight Into

<p>The maritime continent in Southeast Asia is characterized by the frequent convective activities on a wide range of scales, as well as by the seasonal emissions of biomass-burning particles. The emission of biomass-burning particles in this region typically peaks in September and October, whereas its intensity varies considerably from year to year. Since the atmospheric circulation over the region is heavily influenced by a range of meteorological and climatological variabilities, such as ENSO, it is important to quantitatively examine the impacts of biomass-burning particles on clouds while taking weather/climate regimes into account. We investigate the effects of biomass-burning particles on clouds, especially convective ones, with cloud-resolving simulations by the WRF-CHEM model. Instead of focusing on a particular case, our simulations cover an extended period of time in the month of September, allowing us to examine both individual convection and an ensemble of convective clouds developing under different weather/climate regimes and hence different aerosol abundance and distributions. Such long-term and high-resolution simulations over the region will give us an insight into the climate-regime dependent two-way interaction between aerosols and clouds.</p>

Some conclusions regarding long -term biological effects of some major oil spills

1982 ◽  
Vol 297 (1087) ◽  
pp. 335-351 ◽  
Keyword(s):  
Oil Spills ◽  
Biological Effects ◽  
Biologically Active ◽  
Long Term Effects ◽  
Sediment Grain Size ◽  
Petroleum Fractions ◽  
Wide Range ◽  
Time Courses

Many of the world ’s major spills exhibit long-term consequences, associated mainly with lagoons, estuaries and marshes. This is due to the persistence of oil or petroleum fractions in these low-energy environments. The bioavailability of residual oil to infauna is influenced by several factors, such as solubility in water, feeding habit, weathering rate and sediment grain size. The time-courses for these long-term effects vary, but may run into decades for some community perturbations. The effects are at all levels of organization, including cellular, organismic and the community. Although the number of documented long-term effects is small, they involve a wide range of biological processes: development, genetic, growth, feeding and assimilation, photosynthesis, recruitment and fecundity, and community stability. It is important to note that the known effects are probably only representative of a much wider range of possible disorders that have occurred, but which have not been detected. This is due mainly to the selective nature of spill follow-up studies. Long-term spill consequences are generally local phenomena and so far no single spill has, to our limited knowledge, significantly altered entire ecosystems or materially affected fisheries. The combination of several spills can, however, place considerable stress on an environment. Also, so far there is no indication of an increasing mutagenic or carcinogenic load in the marine environment due to biologically active petroleum fractions or to carcinogenic or mutagenic metabolites. There is, however, the possibility of local build-up of these compounds, as in ‘hydrocarbon sink’ areas, where such a burden may become a local problem .

scholarly journals Studying models of balancing selection using phase-type theory

2020 ◽  
Author(s):  
Kai Zeng ◽  
Brian Charlesworth ◽  
Asger Hobolth
Keyword(s):  
Population Size ◽  
Type Theory ◽  
Balancing Selection ◽  
Gene Tree ◽  
Low Frequency ◽  
Allele Frequencies ◽  
Inhomogeneous Phase ◽  
Wide Range ◽  
Phase Type

ABSTRACTBalancing selection is an important process, which maintains genetic variability in many functionally important genes. To increase our understanding of its effects on patterns of genetic diversity, we analyse two models of long-term balancing selection at a biallelic locus, one with a constant population size and the other with recent population size changes, as well as a model of recent balancing selection. We use time-inhomogeneous phase-type theory to obtain the expected properties of the gene tree at a neutral site linked to the target of selection, and the linkage disequilibrium (LD) between the selected and neutral sites. For long-term balancing selection, we show that selection targets with equilibrium allele frequencies close to 50% are easier to detect than targets with unequal allele frequencies. The target is also easier to identify after a population size reduction. The spread of a new mutation under balancing selection initially produces diversity patterns in linked neutral regions that are similar to those for a selective sweep caused by positive selection, including reduced diversity and an excess of both high and low frequency derived variants, as well as excess LD with the selected locus. Although the effects of recent balancing selection are more subtle, patterns of diversity and LD remain in a non-equilibrium state for a much longer period than with a sweep, and provide complementary information regarding the selection event. These results can be used for developing new methods for detecting loci under balancing selection, and illustrate the power of time-inhomogeneous phase-type theory, which can be applied to a wide range of population genetic problems.

Major ions behaviour during evaporation of different saline type water of Western Mongolian lakes (geochemical modelling)

2017 ◽  
Vol 49 (1) ◽  
pp. 163-176 ◽  
Author(s):  
Marina N. Kolpakova ◽  
Olga L. Gaskova
Keyword(s):  
Major Ions ◽  
Geochemical Evolution ◽  
Evaporative Concentration ◽  
Wide Range ◽  
Chloride Sulfate ◽  
Type Water ◽  
Saline Solutions ◽  
First Time ◽  
Calculated Model

Abstract The main Mongolian water resources are lakes whose volume has significantly reduced in recent years as a consequence of global warming. This article presents research on three different types of nearly disposed Western Mongolian lakes with a wide range of brines’ composition: Shaazgai-Nuur (soda), Davsan-Nuur (chloride) and Tonhil-Nuur (sulfate). The aim of this study was to determine the differences in geochemical evolution associated with evaporation-crystallization processes of representative lakes of various chemical types. The modelling was performed by using PHREEQC and HCh software that allows application of Pitzer's approach for saline solutions. The modelling was performed for these natural objects for the first time. The model demonstrated that the evaporation-crystallization processes are different for soda and chloride/sulfate brines. Soda type lake maintained unchanged ion composition while chemical composition of chloride and sulfate lakes went through significant alterations according to a sequence of mineral precipitation. The calculated model did not confirm the possibility of long-term transformation from SO4-Mg brines to Cl-Mg due to evaporative concentration only; additional factors including mixing with inflow water also influence sodium and chloride increase. Close agreement between the model and the actual mineralogical data was observed, testifying to the proper software and reliability of our assumptions.

scholarly journals Stabile Isotope in der Dendroklimatologie | Stable isotopes and dendroclimatology

2004 ◽  
Vol 155 (6) ◽  
pp. 222-232 ◽  
Author(s):  
Kerstin Treydte ◽  
Jan Esper ◽  
Holger Gärtner
Keyword(s):  
Stable Isotopes ◽  
Carbon Isotopes ◽  
Low Frequency ◽  
High Mountain ◽  
Wide Range ◽  
Decadal Variations ◽  
Relevant Field ◽  
Laboratory Procedures ◽  
Stabile Isotope

This paper expounds the basics of isotope fixation in tree rings and relevant field and laboratory procedures. Examples from high mountain regions show both the potential and limits of employing these methods in dendroclimatological studies. Carbon isotopes yield seasonally resolved information on temperature,precipitation and relative humidity, whilst oxygen isotopes provide information on the isotope values of the source water,and thus, on precipitation. Inter-annual and decadal variations, in particular, reflect a strong common climatic signal that extends across a wide range of site ecologies. However, low frequency trends are masked by a non-climatic, human induced long-term trend, especially where carbon isotopes are concerned. At present,detrending methods are of a provisional nature and set a limit to stable isotopes for paleoclimatic questions. Highly resolved plant physiological and biochemical investigations should provide more insight into these unsolved problems.

scholarly journals Performance and hemocompatibility of a novel polysulfone dialyzer: a randomized controlled trial

Kidney360 ◽  
2021 ◽  
pp. 10.34067/KID.0000302021
Author(s):  
Götz Ehlerding ◽  
Ansgar Erlenkötter ◽  
Adelheid Gauly ◽  
Bettina Griesshaber ◽  
James Kennedy ◽  
...  
Keyword(s):  
Cell Activation ◽  
Removal Rate ◽  
Controlled Trial ◽  
Membrane Surface ◽  
Low Frequency ◽  
Contact Activation ◽  
Β2 Microglobulin ◽  
Wide Range ◽  
Middle Molecules

Background: High-flux dialyzers shall effectively remove uremic toxins and be hemocompatible to minimize intradialytic humoral and cellular stimulation and long-term impact on patient outcomes. A new dialyzer with a modified membrane surface has been tested for performance and hemocompatibility. Methods: This multicenter, prospective, randomized, cross-over study applied for one week each the new polysulfone-based FX CorAL 600 (Fresenius Medical Care, Bad Homburg, Germany), the polyarylethersulfone-based Polyflux 170H (Baxter Healthcare Corporation, Deerfield, IL, USA) and the cellulose-triacetate-based SureFluxTM 17UX (Nipro Medical Europe, Mechelen, Belgium) to assess non-inferiority of removal rate of β2-microglobulin of the FX CorAL 600. Performance was assessed by removal rate and clearance of small and middle molecules. Hemocompatibility was assessed through markers of complement, cell activation, contact activation and coagulation. Results: Of 70 patients, 58 comprised the intention-to-treat population. The removal rate of β2-microglobulin of the FX CorAL 600 was non-inferior to both comparators (P<0.0001 vs SureFluxTM 17UX; P=0.0006 vs Polyflux 170H), and superior to SureFluxTM 17UX. The activation of C3a and C5a with FX CorAL 600 was significantly lower 15 min after treatment start than with SureFluxTM 17UX. The activation of sC5b-9 with FX CorAL 600 was significantly lower over the whole treatment than with SureFluxTM 17UX, and lower after 60 min than with Polyflux 170H. The treatments with FX CorAL 600 were well tolerated. Conclusions: FX CorAL 600 efficiently removed small and middle molecules, showed a favorable hemocompatibility profile and was associated with a low frequency of adverse events in the present study with a limited patient number and follow-up time. Further studies with longer observation times are warranted to provide further evidence supporting the use of the new dialyzer in a wide range of therapeutic options and long-term treatments of hemodialysis patients to minimize the potential impact on inflammatory processes.

Sign in / Sign up

Export Citation Format

Share Document