Hydraulic flow through a channel contraction: multiple steady states

We have investigated shallow water flows through a channel with a contraction by experimental and theoretical means. The horizontal channel consists of a sluice gate and an upstream channel of constant width $b_0$ ending in a linear contraction of minimum width $b_c$. Experimentally, we observe upstream steady and moving bores/shocks, and oblique waves in the contraction, as single and multiple steady states, as well as a steady reservoir with a complex hydraulic jump in the contraction occurring in a small section of the $b_c/b_0$ and Froude number parameter plane. One-dimensional hydraulic theory provides a comprehensive leading-order approximation, in which a turbulent frictional parametrization is used to achieve quantitative agreement. An analytical and numerical analysis is given for two-dimensional supercritical shallow water flows. It shows that the one-dimensional hydraulic analysis for inviscid flows away from hydraulic jumps holds surprisingly well, even though the two-dimensional oblique hydraulic jump patterns can show large variations across the contraction channel

The Influence of Justice Thurgood Marshall on the Development of Title VII Jurisprudence

This Article highlights Justice Marshall’s influence on the development of Title VII jurisprudence. Part I presents a brief overview of Justice Marshall’s personal and professional life before becoming a Justice to show how his experience influenced the development of his judicial philosophy. Part II summarizes the Court’s approach to some of the issues left unresolved by Congress in the initial passage of Title VII. Specifically, it explores how the Court determined what would constitute a violation of Title VII and standards of pleading and proof. Part III examines the changes in the Court’s jurisprudence before Justice Marshall retired from the bench. As the majority of Justices became less sympathetic to the protection of African Americans in the workplace, Justice Marshall’s voice of dissent emerged. Part IV concludes with a discussion of the Civil Rights Act of 1991, which vindicated Justice Marshall’s choice to dissent by adopting many of the positions taken in his departure from the majority view

Using an Experiential Learning Design to Teach Photography in Agricultural Communications

Photography is an important competency of agricultural communications graduates and is a core skill taught in the discipline’s curriculum. The [department] at [university] offers an undergraduate photography course twice yearly in two semester formats: a traditional spring semester where photography principles are taught in the classroom and a 12-day experiential intersession semester that allows for flexibility in how and where the course is taught. Both semesters utilize the same instructor, assignments, and grading rubric. While much agricultural communications research has focused on photography as a needed skill, few studies examine photography teaching methods. The purpose of this study was to compare student performance in an agricultural communications digital photography course taught with an experiential learning approach to a traditional classroom approach during the 2016 and 2017 academic calendar years. Kolb’s (1984) experiential learning theory was used as the theoretical framework for this study. Independent-samples t-tests were conducted to compare students’ cumulative mean assignment scores, individual assignment mean scores, and rubric criteria mean scores within the two instruction formats. The results suggest instruction method has an effect on student performance in agricultural communications digital photography courses. Students in the experiential intersession course had significantly higher mean cumulative assignment scores compared to students in the traditional course. While individual assignment performance was less affected by instruction format, students’ understanding of specific photography skills (rubric criteria), especially composition and clarity was higher when in the experiential intersession format

Toxic structures: Speculation and lead exposure in Detroit\u27s single-family rental market

Foreclosure sales permitted investors to purchase large volumes of low-cost residential properties after the last financial crisis, reshaping patterns of property ownership in low-income housing markets across the US. This study links post-foreclosure property acquisitions by investor-landlords to subsequent lead poisoning cases among children under age six living in Detroit, Michigan. We find that the odds of exhibiting elevated blood lead levels (≥ 5 μg/dL) are higher for children living in investor-owned homes purchased through tax foreclosure sale. These findings highlight the potential for property speculation in post-foreclosure housing markets to exacerbate severe and racialized burdens of excess lead toxicity in low-income communities

Determination of the QCD color factor ratio CA/CF from the scale dependence of multiplicity in three jet events

I examine the determination of the QCD color factor ratio CA/CF from the scale evolution of particle multiplicity in e+e- three jet events. I fit an analytic expression for the multiplicity in three jet events to event samples generated with QCD multihadronic event generators. I demonstrate that a one parameter fit of CA/CF yields the expected result CA/CF=2.25 in the limit of asymptotically large energies if energy conservation is included in the calculation. In contrast, a two parameter fit of CA/CF and a constant offset to the gluon jet multiplicity, proposed in a recent study, does not yield CA/CF=2.25 in this limit. I apply the one parameter fit method to recently published data of the DELPHI experiment at LEP and determine the effective value of CA/CF from this technique, at the finite energy of the Z0 boson, to be 1.74+-0.03+-0.10, where the first uncertainty is statistical and the second is systematic.Comment: 20 pages including 6 figures Version 2 corrects typographical error in equation (2

Measuring Community Programs and Policies in the Healthy Communities Study

Childhood obesity is a challenging public health issue facing communities throughout the U.S. Local efforts are believed to be essential to assuring environments that support physical activity and healthy food/beverage consumption among children and their families. However, little is known about how broadly and intensively communities are implementing combinations of programs and policies that address childhood nutrition, physical activity, and weight control. The Healthy Communities Study is a nationwide scientific study in diverse communities to identify characteristics of communities and programs that may be associated with childhood obesity. Data collection occurred in 2013–2015; data analysis will be completed in 2016. As part of the Healthy Communities Study, researchers designed a measurement system to assess the number and scope of community programs and policies and to examine possible associations between calculated “intensity” scores for these programs and policies and behavioral and outcome measures related to healthy weight among children. This report describes the protocol used to capture and code instances of community programs and policies, to characterize attributes of community programs and policies related to study hypotheses, and to calculate the intensity of combinations of community programs and policies (i.e., using the attributes of change strategy, duration, and reach)

Fragmentation Functions for Pions, Kaons, and Protons at Next-to-Leading Order

We present new sets of fragmentation functions for charged pions, charged kaons, and protons, both at the leading and next-to-leading orders. They are fitted to the scaled-momentum distributions of these hadrons measured in e+e- annihilation on the Z-boson resonance at CERN LEP1 and SLAC SLC. These data partly come as light-, charm-, bottom-quark-enriched and gluon-jet samples, which allows us to treat all partons independently, after imposing the SU(2) flavour symmetry relations. In order to gain sensitivity to the scaling violation in fragmentation, we also include data from SLAC PEP, with center-of-mass energy root(s)=29 GeV, in our fits. This allows us to also determine the strong-coupling constant, with a competitive error. LEP1 data on the longitudinal cross section as well as DESY DORIS and PETRA data at lower energies nicely agree with theoretical predictions based on our fragmentation functions.Comment: 28 pages, 11 eps figure

A stability result for solitary waves in nonlinear dispersive equations

The stability of solitary traveling waves in a general class of conservative nonlinear dispersive equations is discussed

Evolution of Coronal Magnetic Field Parameters during X5.4 Solar Flare

The coronal magnetic field over NOAA Active Region 11,429 during a X5.4 solar flare on 7 March 2012 is modeled using optimization based Non-Linear Force-Free Field extrapolation. Specifically, 3D magnetic fields were modeled for 11 timesteps using the 12-min cadence Solar Dynamics Observatory (SDO) Helioseismic and Magnetic Imager photospheric vector magnetic field data, spanning a time period of 1 hour before through 1 hour after the start of the flare. Using the modeled coronal magnetic field data, seven different magnetic field parameters were calculated for 3 separate regions: areas with surface |Bz|≥ 300 G, areas of flare brightening seen in SDO Atmospheric Imaging Assembly imagery, and areas with surface |B| ≥ 1000 G and high twist. Time series of the magnetic field parameters were analyzed to investigate the evolution of the coronal field during the solar flare event and discern pre-eruptive signatures. The data shows that areas with |B| ≥ 1000 G and |Tw|≥ 1.5 align well with areas of initial flare brightening during the pre-flare phase and at the beginning of the eruptive phase of the flare, suggesting that measurements of the photospheric magnetic field strength and twist can be used to predict the flare location within an active region if triggered. Additionally, the evolution of seven investigated magnetic field parameters indicated a destabilizing magnetic field structure that could likely erupt