Transport of bacteria through geologic media

1996 ◽  
Vol 42 (4) ◽  
pp. 410-422 ◽  
Author(s):  
J. R. Lawrence ◽  
M. J. Hendry
Keyword(s):  
Ionic Strength ◽  
Model Development ◽  
Theoretical Development ◽  
Bacterial Transport ◽  
Confocal Laser ◽  
Column Studies ◽  
Advection Dispersion ◽  
And Behavior ◽  
Transport Of Bacteria ◽  
Geologic Media

A review of the current literature on transport of bacteria through geologic media is presented. The review addresses the major controls on bacterial transport. These controls include the nature of the substratum, the solute, and the bacterial cell. Most knowledge on the transport of bacteria through geologic media has been gained from column studies. There is need for some standardization of approaches, particularly with regard to data collection and controls on factors such as ionic strength and flow velocity. Other systems including glass micromodels have been used in conjunction with microscopy and scanning confocal laser microscopy to examine the controls on transport at the pore scale rather than porous medium scale of column studies. Many inconsistencies exist regarding the effect of the numerous variables that impact bacterial sorption in porous media. These variables include the nature of the substratum (i.e., the presence or absence of coatings), chemical composition of the solute (particularly ionic strength), system hydrodynamics, and bacterial variables such as size, shape, hydrophobicity, and electrostatic charge. Mathematical models based on the advective–dispersion equation have been developed to simulate bacterial transport. Within specific limits, these models can approximate most aspects of bacterial transport; however, they neglect parameters such as growth and behavior of bacteria. There is a need for theoretical development, extensive laboratory investigation, and model development before the goal of prediction of bacterial transport at field scale may be realized.Key words: sorption, advection, dispersion, models, facilitated transport.

scholarly journals Inferring the Genetic Influences on Psychological Traits Using MRI Connectivity Predictive Models: Demonstration with Cognition

2019 ◽  
Author(s):  
Alexander S. Hatoum ◽  
Andrew E. Reineberg ◽  
Philip A. Kragel ◽  
Tor D. Wager ◽  
Naomi P. Friedman
Keyword(s):  
Predictive Models ◽  
Model Development ◽  
Genetic Correlations ◽  
Additive Model ◽  
Brain Regions ◽  
Imaging Genetics ◽  
Psychological Traits ◽  
Genetics Research ◽  
Brain Models ◽  
And Behavior

AbstractGenetic correlations between brain and behavioral phenotypes in analyses from major genetic consortia have been weak and mostly non-significant. fMRI models of systems-level brain patterns may help improve our ability to link genes, brains, and behavior by identifying reliable and reproducible endophenotypes. Work using connectivity-based predictive modeling (CBPM) has generated brain-based proxies of behavioral and neuropsychological variables. If such models capture activity in inherited brain systems, they may offer a more powerful link between genes and behavior. As a proof of concept, we develop models predicting intelligence (IQ) based on fMRI connectivity and test their effectiveness as endophenotypes. We link brain and IQ in a model development dataset of N=3,000 individuals; and test the genetic correlations between brain models and measured IQ in a genetic validation sample of N=13,092 individuals from the UKBiobank. We compare an additive connectivity-based model to multivariate LASSO and ridge models phenotypically and genetically. We also compare these approaches to single “candidate” brain areas. We find that predictive brain models were significantly phenotypically correlated with IQ and showed much stronger correlations than individual edges. Further, brain models were more heritable than single brain regions (h2=.155-.181) and capture about half of the genetic variance in IQ (rG=.422-.576), while rGs with single brain measures were smaller and non-significant. For the different approaches, LASSO and Ridge were similarly predictive, with slightly weaker performance of the additive model. LASSO model weights were highly theoretically interpretable and replicated known brain IQ associations. Finally, functional connectivity models trained in midlife showed genetic correlations with early life correlates of IQ, suggesting some stability in the prediction of fMRI models. We conclude that multi-system predictive models hold promise as imaging endophenotypes that offer complex and theoretically relevant conclusions for future imaging genetics research.

scholarly journals XZ-series of unmanned aerial vehicles in 2020

2020 ◽  
Vol 32 ◽  
pp. 134-151
Author(s):  
Svetoslav Zabunov
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Model Development ◽  
Unmanned Aircraft ◽  
Theoretical Development ◽  
Major Work ◽  
Scientific Impact ◽  
Aerial Vehicles ◽  
Utility Models ◽  
Current Article ◽  
Concise Guide

The XZ-series of unmanned aerial vehicles was initiated in 2014 initially as an endeavour of theoretical development of multirotor unmanned aircraft models. The idea and major work was done by the author of the current article, and now, by the year of 2020, the series is still in constant process of inventing new designs. Most of the models were patented at the Bulgarian Patent Office through patents for inventions or utility models. In the recent years, publications on the XZ-series models have appeared in foreign scientific journals with high scientific impact metric. The XZ-series of flying machines includes various types of multi-rotor machines such as standard multi-rotors, fixed wing multi-rotors and compound multi-rotors. This article is a concise guide, as concise as it can be, to the XZ-series of unmanned aerial vehicles as of middle 2020 and, as such, it shall be followed in the future by sequels, published regularly, summarizing the ongoing process of the XZ-series aircraft model development.

scholarly journals Monitoring Bacterial Transport by Stable Isotope Enrichment of Cells

2000 ◽  
Vol 66 (11) ◽  
pp. 4935-4939 ◽  
Author(s):  
William E. Holben ◽  
Peggy H. Ostrom
Keyword(s):  
Stable Isotope ◽  
Stable Carbon Isotope ◽  
Sensitive Detection ◽  
Bacterial Transport ◽  
Spectrometric Analysis ◽  
Bacterial Cells ◽  
Bacterial Populations ◽  
Native Communities ◽  
Groundwater Samples ◽  
And Behavior

ABSTRACT Understanding the transport and behavior of bacteria in the environment has broad implications in diverse areas, ranging from agriculture to groundwater quality, risk assessment, and bioremediation. The ability to reliably track and enumerate specific bacterial populations in the context of native communities and environments is key to developing this understanding. We report a novel bacterial tracking approach, based on altering the stable carbon isotope value (δ13C) of bacterial cells, which provides specific and sensitive detection and quantification of those cells in environmental samples. This approach was applied to the study of bacterial transport in saturated porous media. The transport of introduced organisms was indicated by mass spectrometric analysis of groundwater samples, where the presence of 13C-enriched bacteria resulted in increased δ13C values of the samples, allowing specific and sensitive detection and enumeration of the bacteria of interest. We demonstrate the ability to produce highly13C-enriched bacteria, present data indicating that results obtained with this approach accurately represent intact introduced bacteria, and include field data on the use of this stable isotope approach to monitor in situ bacterial transport. This detection strategy allows sensitive detection of an introduced, unmodified bacterial strain in the presence of the indigenous bacterial community, including itself in its unenriched form.

scholarly journals Psychology of Stress and Coping

Psychology ◽  
2018 ◽  
Author(s):  
Angela R. Wendorf ◽  
Amanda M. Brouwer
Keyword(s):  
Coping Styles ◽  
Stress And Coping ◽  
Coping Resources ◽  
Theoretical Development ◽  
Management Interventions ◽  
Definition Of ◽  
As Stress ◽  
The Mind ◽  
And Coping ◽  
And Behavior

The psychology of stress and coping has been a prominent topic of scientific study and of popular interest over the last century. Applying the study of the mind and behavior to a concept such as stress and coping has led to an evolving definition of stress, more research on its physical, psychological and social effects, and the development of comprehensive ways in which individuals cope with stress. Our understanding of how individuals cope with stress has advanced to include perception of one’s ability to cope, approach to coping, assessment and utilization of coping resources available, and enacting of strategies. We review the psychology of stress and coping as it presents itself in the current evolving research and theoretical development, documenting historical, theoretical, and methodological perspectives on stress and coping. In so doing, we will provide sources and commentary on the definitions of stress, main theories of stress, categories of stressors, consequences of stress, definitions of coping, main theories of coping, coping styles and strategies, assessment of coping, descriptions of coping processes, coping functions and goals, coping resources, and coping and stress management interventions. We would like to acknowledge Samantha Lee for her assistance with this project.

Bacterial transport in laboratory columns and filters: Influence of ionic strength and pH on collision efficiency

1995 ◽  
Vol 29 (7) ◽  
pp. 1673-1680 ◽  
Author(s):  
David G. Jewett ◽  
Thomas A. Hilbert ◽  
Bruce E. Logan ◽  
Robert G. Arnold ◽  
Roger C. Bales
Keyword(s):  
Ionic Strength ◽  
Bacterial Transport ◽  
Collision Efficiency

scholarly journals Model Development for Single Substrate Polycyclic Aromatic Hydrocarbon Biodegradation

2015 ◽  
Vol 773-774 ◽  
pp. 1345-1349
Author(s):  
Norzila Othman ◽  
S. Abdul-Talib ◽  
A. Yassin
Keyword(s):  
Microbial Growth ◽  
Model Development ◽  
Contaminated Sites ◽  
Hydrocarbon Biodegradation ◽  
Monod Equation ◽  
Study Results ◽  
Polycyclic Aromatic ◽  
Suitable Treatment ◽  
And Behavior ◽  
Fate And Behavior

The kinetic of microbial growth and substrate utilization can be used to predict the fate and behavior of contaminants like PAHs in the environment through appropriate models. Further kinetic study results are useful in evaluating and weighing suitable treatment option for remediation and clean up of contaminated sites.. In this research a mathematical model for biodegradation of PAHs using isolated bacteria from municipal sludge was studied.. The model was developed using the Monod equation.. Results showed that the remaining PAHs in all samples decreased within time.

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