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Ongoing efforts to characterize underwater dunes have led to a considerable number of freely available tools that identify these bedforms in a (semi-)automated way. However, these tools differ with regard to their research focus and appear to produce results that are far from unequivocal. We scrutinize this assumption by comparing the results of five recently published dune identification tools in a comprehensive meta-analysis. Specifically, we analyze dune populations identified in three bathymetries under diverse flow conditions and compare the resulting dune characteristics in a quantitative manner. Besides the impact of underlying definitions, it is shown that the main heterogeneity arises from the consideration of a secondary dune scale, which has a significant influence on statistical distributions. Based on the quantitative results, we discuss the individual strengths and limitations of each algorithm, with the aim of outlining adequate fields of application. However, the concerted bedform analysis and subsequent combination of results have another benefit: the creation of a benchmarking data set which is inherently less biased by individual focus and therefore a valuable instrument for future validations. Nevertheless, it is apparent that the available tools are still very specific and that end-users would profit by their merging into a universal and modular toolbox.

Dunes are ubiquitous features in alluvial channels, serve as major agents of sediment transport and contribute significantly to flow resistance. Research in the past decade has illustrated the complexity of dune geometry and widespread occurrence of dunes that have a low leeside angle. However, debate exists concerning the occurrence of such dunes and their formative processes. This paper seeks to further our understanding of low-angle dunes by utilizing data from a robust set of shallow flow laboratory experiments detailing equilibrium bedform morphology across a range of sediment transport conditions. Analysis of bedform morphology demonstrates that dunes with low-angle leesides are generated in shallow laboratory flows, and hence are not restricted to deep rivers. Of the possible processes that have been proposed to explain the formation of low-angle dunes, this finding unequivocally shows that liquefied leeside avalanches, which rely on deep flows for their generation, are not a controlling mechanism. In addition, dunes formed under suspension-dominated conditions possess lower leeside angles compared to those formed in bedload-dominated conditions. However, where bedload transport dominates and sediment suspension is likely of lesser importance, low-angle dunes are still present, and preliminary analysis shows that bedform superimposition can result in lowering of the dune leeside angle. Low and intermediate angle dunes formed in these various conditions also have a lower potential for large-scale, permanent, leeside flow separation compared to angle-of-repose dunes, confirming the need to account for these differences in predictions of flow resistance associated with dune form roughness.

Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members.

Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members.

This study investigates about decolonial artistical practices that question symbols displayed in public spaces. This is done by interventions of monumental figures, and by this the transformation of ephemeral poetics are activated and function as interference in public spaces. On one hand we go through the different ways that interventions in monuments and statues assume; and on the other hand, taking into account two cases, we analyse the power of this actions over public space and the community. In first instance, we review the intervention in the statue of Isabel la Católica in La Paz, Bolivia, done by the movement “Mujeres Creando” —which was renamed “La chola Globalizada” after the intervention— and different actions performed over the monument of Julio Roca, done between 2003 and 2020 in Argentina., Este trabajo indaga sobre activismos artísticos que intervienen de forma crítica símbolos coloniales como estatuas y monumentos, creando acciones efímeras disruptivas que funcionan como interferencias en el espacio público. Abordaremos distintas estrategias que asumen las intervenciones sobre las figuras monumentales; y, a partir de dos casos, analizamos la potencia de estas prácticas en el espacio público y la comunidad. Reseñamos en primera instancia la intervención sobre la estatua de Isabel la Católica en La Paz, Bolivia, por parte del movimiento Mujeres Creando —rebautizada como “La chola Globalizada”— y distintas acciones sobre monumentos a Julio Argentino Roca realizadas entre los años 2003 y 2020 en Argentina.

In natural rivers, flow discharge may fluctuate across a range of time scales – from diurnal to seasonal - but is often most pronounced during hydrographs that may encompass long-duration floods. Under these varying flows, bedforms can be created and modified by the flow without achieving any ‘equilibrium’ state. A lag between changes in flow and the morphological response of the bedforms, termed bedform hysteresis, is commonly present. Importantly for channel management and navigation, since dunes may grow larger during floods, but often experience a lagged decay in size during lowering water levels, critical water depths may be reached for inland shipping. There is also a consensus that dunes possess a more flattened shape, and lower leeside angle, than previously assumed in large rivers and that such dunes do not exhibit a region of permanent flow separation downstream of the dune. This different leeside shape thus questions traditional ideas of flow interactions with dunes, where flow separation in the steep dune lee side leads to energy loss (form drag) that increases flow resistance and energy expenditure within the flow. This paper quantifies dune hysteresis in the River Waal, Netherlands, by investigating how dune morphology changes through flood hydrographs, using high spatial- and temporal- resolution bathymetric data and robust computational analysis methods to produce probability density functions of dune morphology. This quantification aims to provide a better understanding of dune hysteresis in large rivers. The analysis examines several large data sets of river bathymetry from a 13 km reach of the River Waal, Netherlands, in a time series of bi-weekly multibeam echo sounder surveys over the last 12 years. Parameterization includes dune height, wavelength, leeside angle and leeside shape, to assess dune kinematics and hysteresis during different flood hydrographs., Rivers, Ports, Waterways and Dredging Engineering

We propose to reflect on the temporality in Diagonal Cero publication (1962 to 1969), edited by the platense artist Edgardo Antonio Vigo. Work with the concept of montage as a key to temporality, both in terms of Diagonal Cero publication and in the artist’s rewriting books. We propose to examine the projection of Diagonal Cero in the Exposición Internacional de Novísima Poesía, making reference to the assembly of the same. From these descriptions, we take the productions as part of a conception about time that includes the materiality of the publication and the aesthetics of participation., Il s’agira dans cet article de se pencher sur la temporalité à l’œuvre dans la publication Diagonal Cero (1962-1969) éditée par l’artiste platense Edgardo Antonio Vigo. Nous travaillerons avec le concept de montage comme clé pour aborder cette temporalité, à la fois dans la publication de Diagonal Cero et dans les livres de réécriture de l’artiste. Nous examinerons la projection de Diagonal Cero à l’Exposición Internacional de Novísima Poesía (l’Exposition Internationale de la Nouvelle Poésie), par le prisme de son montage. Ces descriptions nous permettront de considérer les productions comme partie prenante d’une conception du temps, intégrant la matérialité de la publication et l’esthétique de la participation., Propomos refletir sobre a temporalidade na publicação Diagonal Cero (1962- 1969), o editor foi o artista platense Edgardo Antonio Vigo. Trabalharemos com o conceito de montagem como uma chave para a temporalidade, tanto em termos da publicação Diagonal Cero quanto nos livros de reescrita do artista. Propomos examinar a projeção da Diagonal Cero na Exposición Internacional de Novísima Poesía, fazendo referência à montagem do mesmo. A partir dessas descrições, tomamos as produções como parte de uma concepção sobre o tempo que inclui a materialidade da publicação e a estética da participação., Se reflexionará sobre la temporalidad en la publicación Diagonal Cero (1962 a 1969), cuyo editor fue el artista platense Edgardo Antonio Vigo. Trabajaremos con el concepto de montaje como clave de la temporalidad, tanto en lo que respecta a la publicación Diagonal Cero como en los libros de reescrituras del artista. Proponemos examinar la proyección de esta revista en la Exposición Internacional de Novísima Poesía haciendo referencia al montaje de la misma. A partir de estas descripciones relevaremos las producciones como parte de una concepción sobre el tiempo que incluye la materialidad de la publicación y la estética de la participación.