scholarly journals An effective parameterization to quantify multiple solute flux breakthrough curves

2014 ◽  
Vol 11 (6) ◽  
pp. 6993-7017
Author(s):  
E. Bloem ◽  
M. de Gee ◽  
G. H. de Rooij
Keyword(s):  
Solute Transport ◽  
Flux Density ◽  
Breakthrough Curves ◽  
Solute Flux ◽  
Spatial Effects ◽  
Solute Fluxes ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
Temporal And Spatial ◽  
The Individual

Abstract. To understand soil and groundwater contamination we study the temporal and spatial aspects of solute transport in the unsaturated zone. One monitoring instrument that captures both aspects is the multi-compartment sampler (MCS). With the MCS developed by Bloem et al. (2010) we are able to measure the downward solute fluxes in 100 compartments at the depth of installation of the MCS, with a minimal disturbance of the flow field. Over time this dataset results in 100 individual solute flux breakthrough curves (BTCs) (temporal aspect). Sorting the BTCs in descending order of solute mass gives the spatial solute distribution curve (spatial aspect). We present a method to quantitatively characterize datasets gathered with MCS (or single samplers installed at multiple locations in a field at the same depth). The method approximates the full set of breakthrough curves using only a single function with four to eight parameters, which combines both temporal and spatial effects of solute transport in soils. This is achieved by modeling the scaled solute flux density breakthrough curves (BTCF) for each compartment as the solution of a conventional one-dimensional equilibrium convection disperion equation (CDE), without modifications. We detect and parameterize any relationships between the resulting transport velocities and dispersion coefficients of the individual BTCFs. Finally the spatial aspect is parameterized using the Beta distribution. This method is based on the flux density BTCs directly, which for transport phenomena is preferred over solute concentrations. In three experiments on undisturbed soils, the resulting approximation matched the data well.

Claudin Tight Junction Proteins: Novel Aspects in Paracellular Transport

2008 ◽  
Vol 28 (6) ◽  
pp. 577-584 ◽  
Author(s):  
Constanze Will ◽  
Michael Fromm ◽  
Dominik Müller
Keyword(s):  
Tight Junction ◽  
Solute Transport ◽  
Molecular Mechanisms ◽  
Family Members ◽  
Transport Processes ◽  
Paracellular Transport ◽  
Solute Flux ◽  
Solute Fluxes ◽  
Essential Components ◽  
Renal Tubular

Claudins are essential components of the intercellular tight junction and major determinants of paracellular solute fluxes across epithelia and endothelia. Many members of this family display a distinct charge or size specificity, whereas others render the epithelium impermeable to transport. Due to intercellular localization, claudin-mediated transport processes are passive and driven by an electrochemical gradient. In epithelial tissues, claudins exhibit a temporal–spatial expression pattern corresponding with regional and local solute transport profiles. Whereas paracellular transport mechanisms in organs such as intestine and kidney have been extensively investigated, little is known about the molecular mechanisms determining solute transport in the peritoneum, and thus the determinants of peritoneal dialysis. Given the ubiquitous expression of claudins in endothelia and epithelia, it is predictable that claudins also contribute to pore formation and determination in the peritoneum, and that they are involved in solute flux. Therefore, we review the basic characteristics of claudin family members and their function as exemplified in renal tubular transport and give an outlook to what extent claudin family members might be of importance for solute reabsorption across the peritoneal membrane.

The Lagrangian Picture, Part I : Fundamentals of the Lagrangian Approach to Solute Transport

2003 ◽  
Author(s):  
Yoram Rubin
Keyword(s):  
Velocity Field ◽  
Solute Transport ◽  
Complex Geometry ◽  
Concentration Field ◽  
Breakthrough Curves ◽  
Lagrangian Approach ◽  
Travel Times ◽  
Solute Fluxes ◽  
Reactive Solutes ◽  
Solute Particle

This chapter explores the principles of the Lagrangian approach to solute transport, with an emphasis on the dispersive action of the spatial variability of the velocity field. We start by developing the tools for characterizing the displacement of a single, small solute particle that will subsequently be used for characterization of the concentration’s variability and uncertainty, and we continue with a discussion of the stochastic description of solute travel times and fluxes. The principles presented in this chapter will be employed in chapter 10 to derive tools for applications such as macrodispersion coefficients, solute travel time moments, the moments of the solute fluxes and breakthrough curves, and transport of reactive solutes. As has been observed in many field studies and numerical simulations, the motion of solute bodies in geological media is complex, making the geometry of the solute bodies hard to predict. Furthermore, the concentration varies erratically, sometimes by orders of magnitude, over very short distances. The variability of the velocity field plays a significant role in shaping this complex geometry, and makes it impossible to characterize the concentration field deterministically. The alternatives we will pursue include characterizing the concentration through its moments such as the expected value and variance, and other descriptors of transport such as solute fluxes and travel times. This line was pursued in chapter 8 using the Eulerian framework. In this chapter we pursue this line from the Lagrangian perspective. Applications of these concepts are presented in chapter 10. Let us consider the displacement of a marked solute particle over time.

scholarly journals Short-term monitoring of Arctic trace metal contamination based on Cetrariella delisei bioindicator in Svalbard

2018 ◽  
Vol 87 (4) ◽  
Author(s):  
Michal Hubert Wegrzyn ◽  
Paulina Wietrzyk-Pełka ◽  
Paweł Nicia ◽  
Sara Lehmann-Konera ◽  
Maria Olech
Keyword(s):  
Trace Metals ◽  
Trace Metal ◽  
Short Term ◽  
Svalbard Archipelago ◽  
Metal Levels ◽  
Spatial Differences ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
Temporal And Spatial ◽  
Term Monitoring

This study focuses on short-term monitoring of trace metals in the Svalbard archipelago. Short-term studies using lichen bioindicators are important because temporary changes in lichen trace metal levels are mainly dependent on air pollutants. Here, we investigated temporal and spatial differences in the content of trace metals such as Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and Zn measured in the lichen thalli of <em>Cetrariella delisei</em>. The temporal aspect was studied in the marine plain of Calypsostranda between 1988 and 2016 and that of Hornsundneset between 1985 and 2008. The spatial aspect was studied between Hornsundneset in 1985 and Calypsostranda in 1988 as well as between Hornsundneset in 2008 and Calypsostranda in 2016. The results revealed an increase in the concentration of Cr, Mn, Ni, and Co for both the aspects, while a decrease in the contents of Cu, Cd, and Mo was observed. Pb content varied, as Pb level increased with time in Hornsundneset but decreased in Calypsostranda. The Zn content showed no significant changes in both temporal and spatial aspects.

Aspect and space

2017 ◽  
Author(s):  
Lucas Champollion
Keyword(s):  
Spatial Domain ◽  
The Other ◽  
Alternative View ◽  
Temporal Domain ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
The Way

This chapter models the relation between temporal aspect (run for an hour vs. *run all the way to the store for an hour) and spatial aspect (meander for a mile vs. *end for a mile) previously discussed by Gawron (2009). The chapter shows that for-adverbials impose analogous conditions on the spatial domain and on the temporal domain, and that an event may satisfy stratified reference with respect to one of the domains without satisfying it with respect to the other one as well. This provides the means to extend the telic-atelic opposition to the spatial domain. The chapter argues in some detail that stratified reference is in this respect empirically superior to an alternative view of telicity based on divisive reference (Krifka 1998).

scholarly journals The role of action effects in motor sequence planning and execution: exploring the influence of temporal and spatial effect anticipation

2021 ◽  
Author(s):  
Rachel M. Brown ◽  
Erik Friedgen ◽  
Iring Koch
Keyword(s):  
Action Planning ◽  
Spatial Effects ◽  
Motor Sequence ◽  
Action Sequence ◽  
Sequential Action ◽  
Spatial Features ◽  
Temporal Features ◽  
Action Sequences ◽  
Temporal And Spatial ◽  
Anticipation Effect

AbstractActions we perform every day generate perceivable outcomes with both spatial and temporal features. According to the ideomotor principle, we plan our actions by anticipating the outcomes, but this principle does not directly address how sequential movements are influenced by different outcomes. We examined how sequential action planning is influenced by the anticipation of temporal and spatial features of action outcomes. We further explored the influence of action sequence switching. Participants performed cued sequences of button presses that generated visual effects which were either spatially compatible or incompatible with the sequences, and the spatial effects appeared after a short or long delay. The sequence cues switched or repeated across trials, and the predictability of action sequence switches was varied across groups. The results showed a delay-anticipation effect for sequential action, whereby a shorter anticipated delay between action sequences and their outcomes speeded initiation and execution of the cued action sequences. Delay anticipation was increased by predictable action switching, but it was not strongly modified by the spatial compatibility of the action outcomes. The results extend previous demonstrations of delay anticipation to the context of sequential action. The temporal delay between actions and their outcomes appears to be retrieved for sequential planning and influences both the initiation and the execution of actions.

scholarly journals Multiple Evidence for Climate Patterns Influencing Ecosystem Productivity across Spatial Gradients in the Venice Lagoon

2021 ◽  
Vol 9 (4) ◽  
pp. 363
Author(s):  
Camilla Bertolini ◽  
Edouard Royer ◽  
Roberto Pastres
Keyword(s):  
Time Series ◽  
Primary Productivity ◽  
Clustering Analysis ◽  
Venice Lagoon ◽  
Spatial Effects ◽  
Spatial Gradients ◽  
Climate Forecasting ◽  
Oxygen Production Rate ◽  
Temporal And Spatial

Effects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy.

Analiza spaţio-temporară a duratei de strălucire a soarelui

2019 ◽  
Author(s):  
Rodica Cojocari ◽  
Keyword(s):  
Sunshine Duration ◽  
Meteorological Station ◽  
Upward Trend ◽  
Trend Line ◽  
Maximum Value ◽  
Increasing Trend ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
Seasonal Aspect ◽  
Annual Amount

In temporal aspect, the duration of sunshine shows a general upward trend. In seasonal aspect, spring season demonstrates an increase of about +0.2 hours, summer - about 0.1 hours, in autumn there is a trend of decreasing, according to the trend line, and the oscillation is equal to zero hours. Also we observe the increase in the number of hours in the spatial aspect. For Briceni meteorological station, the annual amount of sunshine duration varies within the limits of 1544 hours (1980) and 2326 hours (2015). The oscillation limits at the Cahul meteorological station are 1880 hours (1976) and 2604 hours (1963). At the Chisinau meteorological station, there's general increasing trend for the number of hours during which the sunshine duration is maintained, and it exhibits oscillations within 1783 hours (1989) and 2498 hours (1963). In the spatial aspect for winter, this increase +1 hour in Cahul, +0.38 hours in Briceni, and + 0.4 hours / season in Chisinau. In spring, the highest value of +2.2 hours is observed at Briceni and the lowest in Chisinau +1.9 hours / season. At Cahul meteorological station the increase was +1.4 hours. The increase in summer is +1.7 hours in Briceni and Chisinau, and only +0.9 hours in Cahul. Autumn trend line is a downward trend with a -0.3 hours decrease registered at Briceni and Chisinau meteorological stations (minimum values), and -0.6 hours in Cahul, maximum value.

scholarly journals Comparisons between SCIAMACHY and ground-based FTIR data for total columns of CO, CH<sub>4</sub>, CO<sub>2</sub> and N<sub>2</sub>O

2006 ◽  
Vol 6 (7) ◽  
pp. 1953-1976 ◽  
Author(s):  
B. Dils ◽  
M. De Mazière ◽  
J. F. Müller ◽  
T. Blumenstock ◽  
M. Buchwitz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Polynomial Interpolation ◽  
Global Network ◽  
Target Species ◽  
Time Period ◽  
Order Polynomial ◽  
Temporal And Spatial ◽  
The Individual ◽  
Near Future ◽  
Total Column

Abstract. Total column amounts of CO, CH4, CO2 and N2O retrieved from SCIAMACHY nadir observations in its near-infrared channels have been compared to data from a ground-based quasi-global network of Fourier-transform infrared (FTIR) spectrometers. The SCIAMACHY data considered here have been produced by three different retrieval algorithms, WFM-DOAS (version 0.5 for CO and CH4 and version 0.4 for CO2 and N2O), IMAP-DOAS (version 1.1 and 0.9 (for CO)) and IMLM (version 6.3) and cover the January to December 2003 time period. Comparisons have been made for individual data, as well as for monthly averages. To maximize the number of reliable coincidences that satisfy the temporal and spatial collocation criteria, the SCIAMACHY data have been compared with a temporal 3rd order polynomial interpolation of the ground-based data. Particular attention has been given to the question whether SCIAMACHY observes correctly the seasonal and latitudinal variability of the target species. The present results indicate that the individual SCIAMACHY data obtained with the actual versions of the algorithms have been significantly improved, but that the quality requirements, for estimating emissions on regional scales, are not yet met. Nevertheless, possible directions for further algorithm upgrades have been identified which should result in more reliable data products in a near future.

scholarly journals Impact of Climate Change on Crop & Predict the Disease

2021 ◽  
Vol 9 (VI) ◽  
pp. 3063-3070
Author(s):  
Shraddha S. Garud
Keyword(s):  
Climate Change ◽  
Growth And Development ◽  
Climate Changes ◽  
Plant Diseases ◽  
Life Stages ◽  
Social Changes ◽  
Temporal And Spatial Distribution ◽  
Climate Influences ◽  
Temporal And Spatial ◽  
The Individual

The prime need of this world is that the simplest agriculture which decides the event of each country because the survival of the individual is completely obsessed with farming and its best production. Climate changes are in response to changes within the hydrosphere, biosphere, and other atmospheric and interacting factors. Human activities driven by demographic, economic, technological, and social changes have a big impact on activity. The climate influences the incidence further as the temporal and spatial distribution of plant diseases. the foremost factors that control the growth and development of diseases are temperature, light, and water. Climate affects all life stages of the pathogen and host and poses a challenge to many pathosystems. The environmental change, especially when combined with the pathogen and host introductions, may cause unprecedented effects.

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