Comment on “A Model for Total Phosphorus in Saginaw Bay”

The subject paper (Canale and Squire 1976) presents the results of the application of a steady-state mass balance model to chloride and total phosphorus data for Saginaw Bay in 1974. Richardson (1974, 1976) has modeled chloride in Saginaw Bay on both a steady-state and a time variable basis. In this work, the steady-state model was shown to be inadequate for this system, except during stable periods in summer and fall. Since most of the loading of pollutants to the bay does not occur at these times, the time variable model was developed. The purpose of this comment is to compare similar aspects of these projects and to contrast the steady-state and time variable approaches with respect to their ability to simulate observed phenomena and the utility of their results.     

Statistical Analysis of the Spatial and Temporal Variability of the Ratio Chlorophyll A to Phytoplankton Cell Volume in Saginaw Bay,Lake Huron

Chlorophyll a has traditionally been used as an indicator of phytoplankton concentration in natural waters. This parameter has also been widely used by phytoplankton modelers for the purpose of comparing model output with field data. Examination of 1974 field data from Saginaw Bay indicated that chlorophyll a concentrations were inconsistent with phytoplankton cell volume concentrations. Statistical procedures were employed to determine the significance and source of the observed variability in the ratio of chlorophyll a to cell volume concentrations.The procedures employed included t-tests, analysis of variance and polynomial regression. The hypothesis that the natural log of the ratio of chlorophyll a to cell volume was constant in time was tested on six different sampling station groupings representing various spatial divisions of Saginaw Bay. In all cases, this ratio was found to vary significantly at the 95% confidence level. The variability of the ratio decreased when only data from the outer portion of Saginaw Bay were used. Greater than 60% of the variability of the ratio can be removed by using a linear correlation of the natural log chlorophyll a to cell volume ratio with the fraction of diatom cell volume.     

Monthly Streamflow Modeling Based on Self-Organizing Maps and Satellite-Estimated Rainfall Data

Hydrological data provide valuable information for the decision-making process in water resources management, where long and complete time series are always desired. However, it is common to deal with missing data when working on streamflow time series. Rainfall-streamflow modeling is an alternative to overcome such a difficulty. In this paper, self-organizing maps (SOM) were developed to simulate monthly inflows to a reservoir based on satellite-estimated gridded precipitation time series. Three different calibration datasets from Três Marias Reservoir, composed of inflows (targets) and 91 TRMM-estimated rainfall data (inputs), from 1998 to 2019, were used. The results showed that the inflow data homogeneity pattern influenced the rainfall-streamflow modeling. The models generally showed superior performance during the calibration phase, whereas the outcomes varied depending on the data homogeneity pattern and the chosen SOM structure in the testing phase. Regardless of the input data homogeneity, the SOM networks showed excellent results for the rainfall-runoff modeling, presenting Nash–Sutcliffe coefficients greater than 0.90.

Graphical Abstract

     

Development and Comparison of Two Fast Surrogate Models for Urban Pluvial Flood Simulations

Detailed full hydrodynamic 1D-2D dual drainage models are a well-established approach to simulate urban pluvial floods. However, despite modelling advances and increasing computational power, this approach remains unsuitable for many real time applications. We propose and test two computationally efficient surrogate models. The first approach links a detailed 1D sewer model to a GIS-based overland flood network. For the second approach, we developed a conceptual sewer and flood model using data-driven and physically based structures, and coupled the model to pre-simulated flood maps. The city of Ghent (Belgium) is used as a test case. Both surrogate models can provide comparable results to the original model in terms of peak surface flood volumes and maximum flood extent and depth maps, with a significant reduction in computing time.     

Organizing College Athletes Utilizing the Civil Rights Unionism Model

In January 2014, Northwestern University (NU) football players filed a certification election petition with the National Labor Relations Board’s (NLRB) Chicago regional office. After the NLRB ruled that they were employees having the legal right to unionize, the football players voted at the end of April 2014 with NU immediately appealing the regional director’s ruling after the balloting. In mid-August 2015, the Washington D.C. NLRB declined jurisdiction in this case, ending the football players’ unionization attempt. Because of the NLRB’s appellate ruling, however, unionization of college athletes remains a distinct possibility. Since a majority of U.S. collegiate basketball and football players are black, this paper argues that the model of unionism that should be adopted in any unionization attempt of these college athletes is civil rights unionism which represents a continuation of the historic, collective struggle of Black athletes to obtain their rights on athletic fields and in classrooms.     

Mercantilism: a materialist approach

ABSTRACT

Historians and economists have shown renewed interest in mercantilism over the last couple of years. From this interest, a dispute has arisen about whether mercantilism should be seen as an incoherent economic thought or if it is possible to ‘reconstruct’ its basic principles. In line with this latter attempt, this paper is intended to provide a materialist explanation for varying degrees of belief in shared mercantilist assumptions. My hypothesis is that belief in mercantilist assumptions is significantly dependent upon how economic and security issues materially interact in a given time and space, with uncertainty and insecurity profoundly favouring mercantilist dispositions in economic thought. To analyse this hypothesis, the paper sets the first steps for relating the credibility of mercantilism with changes in British economic and military history from the sixteenth to the nineteenth century. Section 3 presents ideas to further investigate this hypothesis. Section 4 concludes the paper.