A simple model to separately simulate point and diffuse nutrient signatures in stream flows

2012 ◽  
Vol 44 (3) ◽  
pp. 538-553 ◽  
Author(s):  
Andrew R. Slaughter ◽  
Denis A. Hughes
Keyword(s):  
Simple Model ◽  
Point Source ◽  
Source Model ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Statistical Regression ◽  
Management Scenarios ◽  
Diffuse Source ◽  
Wide Range ◽  
Source Component

A simple model has been developed to simulate the relationships between stream flow and point and diffuse nutrient concentrations. The point source component is based on a mechanistic approach (including uncertainty), while the diffuse component relies on a statistical regression model. The model is explained and its application illustrated using flow and nutrient data from the South African Department of Water Affairs national monitoring database. The study sites represent a wide range of different combinations of point and diffuse source contributions to the total nutrient signature. The model has been successfully calibrated against the observed data and the study concludes that the point source component offers opportunities for use as a scenario assessment management tool, largely related to its mechanistic basis. However, further research is required to link the parameters of the diffuse source model to diffuse load causative factors so that the model can be used effectively in un-gauged situations or to assess management scenarios.

scholarly journals MUREN: a robust and multi-reference approach of RNA-seq transcript normalization

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yance Feng ◽  
Lei M. Li
Keyword(s):  
Biological Significance ◽  
Housekeeping Genes ◽  
R Package ◽  
Data Sets ◽  
Statistical Regression ◽  
Rna Seq ◽  
Least Trimmed Squares ◽  
Standard Data ◽  
Wide Range ◽  
Multiple References

Abstract Background Normalization of RNA-seq data aims at identifying biological expression differentiation between samples by removing the effects of unwanted confounding factors. Explicitly or implicitly, the justification of normalization requires a set of housekeeping genes. However, the existence of housekeeping genes common for a very large collection of samples, especially under a wide range of conditions, is questionable. Results We propose to carry out pairwise normalization with respect to multiple references, selected from representative samples. Then the pairwise intermediates are integrated based on a linear model that adjusts the reference effects. Motivated by the notion of housekeeping genes and their statistical counterparts, we adopt the robust least trimmed squares regression in pairwise normalization. The proposed method (MUREN) is compared with other existing tools on some standard data sets. The goodness of normalization emphasizes on preserving possible asymmetric differentiation, whose biological significance is exemplified by a single cell data of cell cycle. MUREN is implemented as an R package. The code under license GPL-3 is available on the github platform: github.com/hippo-yf/MUREN and on the conda platform: anaconda.org/hippo-yf/r-muren. Conclusions MUREN performs the RNA-seq normalization using a two-step statistical regression induced from a general principle. We propose that the densities of pairwise differentiations are used to evaluate the goodness of normalization. MUREN adjusts the mode of differentiation toward zero while preserving the skewness due to biological asymmetric differentiation. Moreover, by robustly integrating pre-normalized counts with respect to multiple references, MUREN is immune to individual outlier samples.

scholarly journals A Review of Nontraditional Biomanipulation

2008 ◽  
Vol 8 ◽  
pp. 1184-1196 ◽  
Author(s):  
Xia Zhang ◽  
Ping Xie ◽  
Xiaoping Huang
Keyword(s):  
Algal Blooms ◽  
Algal Species ◽  
Planktivorous Fish ◽  
Bighead Carp ◽  
Cyanobacterial Blooms ◽  
Management Tool ◽  
Nutrient Concentrations ◽  
Effective Management ◽  
Nuisance Algae ◽  
The Impact

The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels.Although small enclosures increase spatial overlap between predators and prey, leading to overestimates of the impact of predation, microcosm and whole-lake experiments have revealed similar community responses to major factors that regulate lake communities, such as nutrients and planktivorous fish. Both enclosure experiments and large-scale observations revealed that the initial phytoplankton community composition greatly impacted the success of biomanipulation. Long-term observations in Lake Donghu and Lake Qiandaohu have documented that silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) (two filter-feeding planktivorous species commonly used in management) can suppress Microcystis blooms efficiently. The introduction of silver and bighead carp could be an effective management technique in eutrophic systems that lack macrozooplankton. We confirmed that nontraditional biomanipulation is only appropriate if the primary aim is to reduce nuisance blooms of large algal species, which cannot be controlled effectively by large herbivorous zooplankton. Alternatively, this type of biomanipulation did not work efficiently in less eutrophic systems where nanophytoplankton dominated.

scholarly journals Usage and Scaling of an Open-Source Spiking Multi-Area Model of Monkey Cortex

2021 ◽  
pp. 47-59
Author(s):  
Sacha J. van Albada ◽  
Jari Pronold ◽  
Alexander van Meegen ◽  
Markus Diesmann
Keyword(s):  
Open Source ◽  
Large Scale ◽  
Network Models ◽  
Macaque Monkey ◽  
Source Model ◽  
Model Specification ◽  
Data Sets ◽  
Neural Network Models ◽  
Wide Range ◽  
Ict Infrastructure

AbstractWe are entering an age of ‘big’ computational neuroscience, in which neural network models are increasing in size and in numbers of underlying data sets. Consolidating the zoo of models into large-scale models simultaneously consistent with a wide range of data is only possible through the effort of large teams, which can be spread across multiple research institutions. To ensure that computational neuroscientists can build on each other’s work, it is important to make models publicly available as well-documented code. This chapter describes such an open-source model, which relates the connectivity structure of all vision-related cortical areas of the macaque monkey with their resting-state dynamics. We give a brief overview of how to use the executable model specification, which employs NEST as simulation engine, and show its runtime scaling. The solutions found serve as an example for organizing the workflow of future models from the raw experimental data to the visualization of the results, expose the challenges, and give guidance for the construction of an ICT infrastructure for neuroscience.

Analysis of Thermal Radiation Models for Large Open Pool Fire on Ship Deck

2013 ◽  
Vol 470 ◽  
pp. 259-262
Author(s):  
Li Bin Ding ◽  
Jin Yun Pu ◽  
Kai Ren
Keyword(s):  
Heat Flux ◽  
Thermal Radiation ◽  
Point Source ◽  
Engineering Design ◽  
Source Model ◽  
Heat Fluxes ◽  
Pool Fire

Three radiation models are discussed in the present paper. The heat fluxes vary considerably between different methods. In all models, fluxes vary highly on the position of nearing the flame and are almost identical on the far away position. Heat fluxes calculated from point source model is less than other two models, and Shokri-Beyler model is highest. Shokri-Beyler method is most applicable at heat fluxes greater than 5 KW/m2 and recommended in engineering design, and Mudan model is not applicable for calculating the heat flux nearing the flame.

scholarly journals From point source to diffuse source of contaminants: The example of mercury dispersion in the Paglia River (Central Italy)

CATENA ◽  
2019 ◽  
Vol 172 ◽  
pp. 488-500 ◽  
Author(s):  
Antonella Colica ◽  
Marco Benvenuti ◽  
Laura Chiarantini ◽  
Pilario Costagliola ◽  
Pierfranco Lattanzi ◽  
...  
Keyword(s):  
Point Source ◽  
Central Italy ◽  
Diffuse Source ◽  
Paglia River

Modern Downsizing

2021 ◽  
pp. 1970-1983
Author(s):  
Grzegorz Wojtkowiak
Keyword(s):  
Financial Analysis ◽  
Management Tool ◽  
Future Research ◽  
Research Directions ◽  
Good Practices ◽  
Strategic Option ◽  
Wide Range ◽  
Future Research Directions ◽  
Points Of View

The aim of the chapter is to present the concept of downsizing from different points of view: as a strategic option, as a management tool and as a phenomenon. It describes the evolution of the term, its definitions, and different directions of development. A scale and possible outcomes are described on the basis of financial analysis; however it also discusses the role of non-financial aspects. The chapter points out reasons, aims and a wide range of tools that may be used during implementation of downsizing. One of the conclusions of the chapter is to present future research directions aiming at increasing knowledge of managers and providing them with detailed good practices.

A global approach to hierarchical classification of coastal waters at different spatial scales: the NEA case

2016 ◽  
Vol 97 (3) ◽  
pp. 465-476 ◽  
Author(s):  
José A. Juanes ◽  
Araceli Puente ◽  
Elvira Ramos
Keyword(s):  
Coastal Waters ◽  
Spatial Scales ◽  
Atlantic Coast ◽  
Coastal Areas ◽  
Biological Information ◽  
Management Tool ◽  
Global Approach ◽  
Ne Atlantic ◽  
Wide Range

Ecological classification of coastal waters has become increasingly important as one of the basic issues in the biology of conservation. Management and protection of coastal areas take place at different spatial scales. Thus, proper classification schemes should integrate equivalent information at various levels of definition in order to show its feasibility as a useful tool for assessment of coastal environments at the required scales. In this work, a global approach applied to the classification of the NE Atlantic coast is analysed in order to discuss pros and cons regarding different conceptual and technical issues for effective implementation of such a management tool. Using the hierarchical system applied at three different geographic scales: Biogeographic (NE Atlantic coast), Regional (Bay of Biscay) and Local (Cantabria region), five different topics were considered for debating strengths and weaknesses of the methodological alternatives at those spatial scales, using for validation the rocky shore macroalgae as a representative biological element of benthic communities. These included: (i) the spatial scales; (ii) the physical variables and indicators; (iii) the classification methodologies; (iv) the biological information; and (v) the validation procedure. Based on that analysis, the hierarchical support system summarized in this paper provides a management framework for classification of coastal systems at the most appropriate resolution, applicable to a wide range of coastal areas. Further applications of the physical classification for management of biodiversity in different environmental scenarios are also analysed.

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