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Rivers and people are tightly coupled. How people relate to rivers dictates their understanding of rivers and approaches to river management. The numerous ways people interact with rivers create complex patterns of social–ecological relationships and interdependencies. Despite this tight coupling, rivers and humans are often studied and managed as separate entities, to the detriment of river environments. Conceptual pluralism is required to move beyond existing practice to avoid irretrievable loss of ways of framing and working with our river environments. The articles in this special issue approach human–river relationships from three perspectives. First, there is a subset that enters the discussions via the human aspects of relationships with rivers, particularly the human frames, metaphors, definitions, or concepts used to reflect on human activities related to rivers. The second subset approaches relationships via the river dimensions, with particular focus on the impacts of human modifications to river ecosystems. Finally, the third subset more fully emphasizes the relationships between humans and rivers. The wide‐ranging dialogue provided in these articles highlights the need for a wider research agenda for rivers that embraces social–ecological systems and other integrative, inclusive ways of understanding. As a collective, these articles advocate the value of creating new river knowledge embedded within a social–ecological context, action, and advocacy. [ABSTRACT FROM AUTHOR]

Objective: Given that the harvested fish from five separate fishing grounds belong to one large mixed population, our objective is to develop an overall abundance index for Lake Whitefish Coregonus clupeaformis in Michigan waters of southern Lake Huron. Methods: We analyzed catch‐and‐effort data for individual fishing trips to five separate fishing grounds and used Bayesian information criterion to select the best model struture. Result: The best model included the year × area × month interaction as a random effect, representing the random component in fishery dynamics that were influenced by both fishing practices and fish abundance. The best model also included the fixed effects of area × month interaction, a result consistent with our hypothesis that the seasonal spatial migrations of Lake Whitefish provide the links among the fisheries in separate fishing grounds, and the fishery yields from these separate areas were all dependent on the production in southern Lake Huron as a whole. After adjusting for the random effect of year × area × month interaction and the fixed effects of area × month interaction, the estimated patterns for the fixed year effect indicated that the Lake Whitefish abundance in Michigan waters of southern Lake Huron declined during the late 2000s but has been relatively constant after 2012. Conclusion: The declines in annual fishery yield were due to and could be explained more by the decreases in fish abundance through 2012 but thereafter primarily reflected the declines in annual fishing effort as the fisheries continued to adjust to the changed fishing conditions. We also provided general lessons for studying fisheries without fishery independent surveys but with detailed seasonal and spatial catch‐and‐effort data. Impact statementThis study and its findings have direct implication for current management of the Lake Whitefish fisheries. [ABSTRACT FROM AUTHOR]

The cover image is based on the article Human – River Relationships by Catherine Allan et al., https://doi.org/10.1002/rra.4379. [ABSTRACT FROM AUTHOR]

Several comparative studies are conducted to explain the mechanisms involved in the circuit attenuation that is used in the helix traveling-wave-tube (TWT) simulation codes. The discussed ad hoc model is shown to be extremely efficient and accurate in determining the attenuation rates.

Polycrystalline storage films are applied in various fields of x-ray radiography. Depending on the application, different requirements exist for the sensitivity and spatial resolution of the film, and these are related to light scattering in the film. Scattering is controlled by optical properties of the storage medium, e.g., the scattering length by the grain size, the absorbance by the choice of the binder, and the geometric boundary conditions by the film thickness. A method treating the scattering of light as a diffusionlike process is presented. The sensitivity, resolution, and other image properties are determined from the optical properties. The influence of the scattering length, absorbance, and thickness on image parameters is calculated and discussed. The results indicate that optimizing the image properties of the film can be achieved by a reduction of the absorbance and an increase in film thickness to the penetration depth of the x rays. Furthermore, it is shown that the resolution of the film can be set strictly according to the requirements of an individual application if the scattering length in the medium is adjusted. Key words: BaFBr:Eu, image plate, image quality, light scattering, line-spread function, modulation transfer function, photon diffusion, photostimulated luminescence, sensitivity, spatial resolution, storage phosphor.

Optical and thermoluminescence spectroscopy help identify the electron and hole storage sites in the x-ray storage phosphor RbI:X that are involved in the photostimulated luminescence process of RbI:X. F- and Z type and T1(sub 0) sites act as electron storage centers when V(sub k-) and dopant-related centers pose as hole-trapping sites. Specific dopant preference produces storage phosphors with varying physical properties. T1(sub 0) sites efficiently trap the varying physical properties at temperatures below 180 K in the T1(super +)-doped material.