ABSTRACT Sandy beaches have different shoreline change rates (i.e., erosion/accretion rates). An erosive process on beaches poses risks for human-occupied areas. One example is Matinhos Beach (state of Paraná - Brazil), which has an average annual erosion rate of around 1.5 m yr-1 This study applied a methodology that combines in situ measurements and numerical modeling to simulate the physical processes in the coastal area of Matinhos during the 2018 Austral winter. Monthly DGPS surveys were carried out in the study area from June to September. The MOHID modeling system was applied to simulate hydrodynamics and sediment transport, considering waves and tidal forcing validated with in situ data. The WAVEWATCH III and SWAN models were applied in a nesting approach to simulate the waves at Matinhos Beach. The GFS was used to assess the wind conditions. The study period showed a dynamic evolution of accretion and erosion between monthly measurements with no clear pattern in most profiles. Significant sand accumulation was observed near the headland. Morphological changes were minor due to the predominance of low energy without significant storm events. The measured morphological changes are in line with the residual littoral drift obtained from the modeling results for the period. The residual current velocities were towards the southwest, with magnitudes ranging from 0.15 m s-1 to 0.2 m s-1. A slight variation in the angle of wave incidence (10°) may change the direction (southwest or northeast) and intensity of the littoral drift. The applied methodology can reduce uncertainty and support effective coastal management. However, the seasonal scales of wave climate cannot be disregarded, nor can the need for coastal oceanographic data. i.e., ie i e (i.e. erosionaccretion rates. . rates) humanoccupied human occupied areas state Brazil, Brazil , Brazil) 15 1 5 1. yr1 yr yr- 201 winter September transport data conditions profiles headland events southwest 015 0 0.1 s1 s s- 02 2 0. s1. 10° 10 (10° northeast management However disregarded i.e. (i.e 20 01 (10 i.e (1 (

ABSTRACT Background. The recruitment of branching corals in the eastern Pacific is poorly understood despite being of paramount importance to the dynamics of coral populations. Experimental studies provide a non-destructive means to evaluate recruitment and compare settlement materials. Goals. To study Pocillopora recruitment on PVC and terracotta tiles in Bahía Ixtapa-Zihuatanejo (Mexican Pacific). Methods. We deployed 40 square (10 x 10 x 0.5 cm) experimental (20 PVC and 20 unglazed terracotta) tiles arranged as Calcification/Accretion Units at the Islote Zacatoso reef. Results. We observed two coral recruits at the edges of terracotta tiles, presumably due to light availability, and no recruits on horizontal sides, which may have been due to siltation stress, predation, or biofouling. No recruits were found on PVC tiles. Conclusions. Our findings indicate that the coral recruitment is low in the study area and that the terracotta tiles may be a better experimental substrate than PVC tiles to assess pocilloporid coral recruitment in the Mexican Pacific; however, further studies are needed to clarify this assumption.

RESUMEN Antecedentes. El reclutamiento de corales ramificados en el Pacífico oriental tropical está poco documentado, a pesar de la importancia que tiene para entender su dinámica poblacional. Los estudios experimentales proporcionan un medio no destructivo para evaluar el reclutamiento y comparar diferentes materiales. Objetivo. Estudiar el reclutamiento de Pocillopora en placas de PVC y de terracota en Bahía Ixtapa-Zihuatanejo, en el Pacífico mexicano. Métodos. Colocamos 40 placas cuadradas (10 x 10 x 0.5 cm), 20 de PVC y 20 de terracota armadas como Unidades de Calcificación/Acreción en el arrecife Islote Zacatoso. Resultados. Observamos dos reclutas de coral en la orilla de las placas de terracota pero ninguno en los lados horizontales, posiblemente debido a la disponibilidad de luz, el estrés por sedimentación, la depredación, o el sobrecrecimiento por biota incrustante. No encontramos reclutas en ninguna de las placas de PVC. Conclusiones. Nuestros hallazgos indican que el reclutamiento coralino es bajo en la zona de estudio y que las placas de terracota pueden ser un mejor sustrato experimental que las de PVC para evaluar el reclutamiento de corales pociloporidos en el Pacífico mexicano; sin embargo, se necesitan más estudios para corroborar esta suposición.

ABSTRACT Background. Sclerobionts (e.g., calcareous algae, bryozoans, polychaetes, mollusks, and barnacles) produce reef calcium carbonate (CaCO3). Their contribution is key to maintaining positive CaCO3 balances, especially in marginal reefs. Objective. To compare the production of CaCO3 by sclerobionts in two marginal reefs of the Mexican Pacific: Las Gatas (LG), in Zihuatanejo Guerrero Bay, and La Llave (LL), in Bahía de Los Angeles (Gulf of California). Methods. CAUs (Calcification/Accretion Units) were used to promote sclerobiont recruitment during two deployment times: 6 and 15 months. Results. The calcification rate was high at six months and then decreased due to rapid colonization and initial growth, followed by a decrease over time. Sclerobionts deposited 1.2 ± 0.4 kg CaCO3 m-2 yr-1 in LG, which represents 7% of the production of branching corals in the Mexican South Pacific (17.2 kg m-2 yr-1), while in LL, they deposited 2.1 ± 0.7 kg CaCO3 m-2 yr-1; equivalent to 20% of the production of massive corals in the area (10.1 kg m-2 yr-1). The groups that deposited most CaCO3 were mollusks and bryozoans in LG (up to 0.65 ± 0.16 kg m-2 yr-1) and barnacles in LL (up to 2.32 ± 0.35 kg m-2 yr-1). Conclusions. These results highlight the role of heterotrophs as secondary calcifiers both in LG, a site impacted by anthropogenic activity, and in LL, an area with low anthropogenic impact but high biological productivity associated with upwellings. This finding implies that the environmental conditions at the study sites limit the calcification of primary calcifiers (i.e., corals and CCA) but promote that of secondary calcifiers, with potential geomorphic repercussions.

RESUMEN Antecedentes. Los esclerobiontes (e.g., algas calcáreas, briozoos, poliquetos, moluscos, y balanos) participan en la producción de carbonato de calcio (CaCO3) arrecifal. Su contribución es vital para mantener balances de CaCO3 positivos, especialmente en arrecifes marginales. Objetivo. Comparar la producción de CaCO3 por esclerobiontes en un arrecife sujeto a estrés antropogénico - Las Gatas (LG), en la bahía de Zihuatanejo Guerrero, y otro bajo condiciones ambientales altamente fluctuantes - La Llave (LL), en Bahía de Los Ángeles (Golfo de California). Métodos. Se utilizaron CAUs (Calcification/Accretion Units) para promover el reclutamiento de esclerobiontes durante dos periodos de inmersión: 6 y 15 meses. Resultados. La tasa de calcificación fue alta a los 6 meses y luego disminuyó debido a la rápida colonización y crecimiento inicial seguido de una disminución con el tiempo. Los esclerobiontes depositaron 1.2 ± 0.4 kg CaCO3 m-2 año-1 en LG, lo que representa el 7% de la producción de corales ramificados en el Pacífico sur mexicano (17.2 kg m-2 año-1), mientras que en LL depositaron 2.1 ± 0.7 kg CaCO3 m-2 año-1, equivalente al 20% de la producción de corales masivos en la zona (10.1 kg m-2 año-1). Los grupos que más CaCO3 depositaron fueron los moluscos y los briozoos en LG (hasta 0.65 ± 0.16 kg m-2 año-1), y los balanos en LL (hasta 2.32 ± 0.35 kg m-2 año-1). Conclusiones. Estos resultados destacan el papel de los heterótrofos como calcificadores secundarios tanto en LG, un sitio impactado por actividad antropogénica, como en LL, un sitio con bajo impacto antropogénico, pero con alta productividad biológica asociada a surgencias. Este hallazgo implica que las condiciones ambientales en los sitios de estudio limitan la calcificación de los calcificadores primarios (i.e., corales y CCA) pero estimulan la de calcificadores secundarios, con potenciales repercusiones geomórficas.

ABSTRACT Background. Coral reefs provide several important geo-ecological functions essential for the sustainability of coastal human communities. However, during the last 50 years, reef ecosystems are experiencing rapid degradation caused by natural and anthropogenic disturbances. One consequence of the above has been the reduction in the carbonate production rate and the structural complexity of these systems. Particularly, the loss of key coral species in the construction of reefs has compromised the functionality of the ecosystem. Objective. In this study we used an adaptation of the ReefBudget methodology to measure the calcium carbonate budget in the reef of La Entrega, Oaxaca, Mexico. Methods. Six transects were carried out to estimate the abundance of eroding fish (25 x 4 m), sea urchins (25 x 2 m) and the composition of the benthos. Results. When carrying out the corresponding calculations, it was found that in La Entrega 13.72 kg m-2 year-1 (commonly referred as “G”) are produced, the endobioerosion (including erosion by sponges) calculated was 5.65 G. The sea urchin erosion is 0.12 G and that of fish is 0.73 G; the resulting net carbonate budget was 7.21 G. The accretion rate (vertical reef growth) at La Entrega reef was 7.07 mm yr-1. We consider it important to mention that the reef patch at La Entrega is relatively small (approximately 324 x 233 m) compared to formations in the Caribbean or Indo-Pacific regions. Conclusions. Net production at La Entrega is higher than estimated for most Caribbean reefs (2-4 G) but lower than that of the Indo-Pacific (5-14 G). Differences in the balance between regions are mainly associated with differences in the abundances of builder species in each region. According to what was modeled in this work, the La Entrega reef patch presents a sufficient accretion rate to deal with a possible rise in sea level under the RCP 4.5 and 2.6 scenarios (4 and 7 mm, respectively).

RESUMEN Antecedentes. Los arrecifes de coral proporcionan diversas funciones geo-ecológicas importantes esenciales para la sostenibilidad de las comunidades humanas costeras. Sin embargo, durante los últimos 50 años, los ecosistemas arrecifales están experimentando una rápida degradación ocasionada por perturbaciones naturales y antropogénicas. Una consecuencia de lo anterior ha sido la reducción de la tasa de producción de carbonatos y la complejidad estructural de estos sistemas. Particularmente, la pérdida de especies coralinas clave en la construcción de arrecifes ha comprometido la funcionalidad del ecosistema. Objetivo. En este estudio utilizamos una adaptación de la metodología ReefBudget para medir el balance de carbonato de calcio en el arrecife de La Entrega, Oaxaca, México. Métodos. Se realizaron seis transectos para estimar la de abundancia de peces erosionadores (25 x 4 m), erizos (25 x 2 m) y la composición del bentos. Resultados. Al realizar los cálculos correspondientes, se encontró que en La Entrega se producen 13.72 kg m-2 año-1 (unidades comúnmente referidas con “G”), la endobioerosión (incluida la erosión por esponjas) calculada fue de 5.65 G. La erosión por erizos es de 0.12 G y la de peces es de 0.73 G; el balance neto de carbonatos resultantes fue de 7.21 G. La tasa de acreción (crecimiento vertical del arrecife) en el arrecife de La Entrega fue de 7.07 mm año-1. Consideramos importante mencionar que el parche arrecifal en La Entrega es relativamente pequeño (aproximadamente 324 x 233 m) en comparación con las formaciones de regiones del Caribe o el Indo-Pacífico. Conclusiones. La producción neta en La Entrega es superior a la estimada en la mayoría de los arrecifes del Caribe (2-4 G) pero más baja que la del Indo-Pacífico (5-14 G). Las diferencias en el balance entre regiones están, principalmente, asociadas a las diferencias en las abundancias de especies constructoras en cada región. De acuerdo con lo modelado en este trabajo, el parche arrecifal de La Entrega presenta una tasa de acreción suficiente para lidiar con una posible elevación en el nivel del mar bajo los escenarios RCP 4.5 y 2.6 (4 y 7 mm, respectivamente).

ABSTRACT Climate-smart agriculture (CSA) practices, mainly no-tillage (NT), cover cropping (CC), soil fertilization with organic amendments (OA), and crop-livestock (CL) and crop-livestock-forestry (CLF) systems, has been widely adopted in areas from Brazilian Cerrado. The CSA may partly offset former soil C losses and contribute to climate change mitigation. However, contradictory findings brought uncertainties about the effect of CSA on soil C. Here, by a systematic review of 87 papers and using 621 data pairs, we provided a pervasive biome-scale analysis of soil C stock changes associated with the adoption of CSA across Brazilian Cerrado. All CSA practices evaluated showed average positive rates of C stock change, indicating a general tendency of soil C accretion after its adoption. In areas under NT, CC and CLF, greater rates were estimated for the deeper soil profile evaluated (0.00-1.00 m) (1.24 ± 0.85, 0.54 ± 0.54 and 1.00 ± 1.47 Mg ha–1 yr–1, respectively), while OA and CL showed more soil C accretion when the assessment was limited down to 0.10 m depth (0.82 ± 0.60 and 0.59 ± 0.66 Mg ha–1 yr–1, respectively). Unfortunately, the lack of basic information precluded any attempt to statically compare our estimations. In this sense, we must be cautious in stating that soil C sequestration occurs at those rates after the adoption of CSA practices. Despite these limitations, the results clearly show that the diversification and intensification of agricultural areas in the Cerrado by the adoption of CSA is a promising pathway to increase soil C stocks, and consequently, contribute to climate change mitigation and adaptation. Finally, our findings emphasize the importance of efforts that stimulate farmers to adopt these practices on large scale, such as Brazil’s Low-Carbon Agriculture Plan, besides providing sound empirical evidence about the role of soil C sequestration in Brazil achieving its Nationally Determined Contributions commitments. Climatesmart Climate smart (CSA notillage no tillage NT , (NT) CC, (CC) OA, (OA) croplivestock crop livestock (CL croplivestockforestry forestry CLF (CLF systems However Here 8 62 pairs biomescale biome scale 0.001.00 000100 0.00 0 00 1 (0.00-1.0 1.24 124 24 (1.2 085 85 0.85 054 54 0.5 100 1.0 147 47 1.4 ha1 ha ha– yr1 yr yr–1 respectively, respectively respectively) 010 10 0.1 0.82 082 82 (0.8 060 60 0.6 059 59 066 66 respectively. . Unfortunately estimations sense limitations stocks consequently adaptation Finally Brazils s LowCarbon Low Carbon Plan commitments (NT (CC (OA 6 001 0.001.0 00010 000 0.0 (0.00-1. 1.2 12 2 (1. 08 0.8 05 5 0. 1. 14 4 yr– 01 (0. 06 0.001. 0001 (0.00-1 (1 (0 0.001 (0.00- ( (0.00 (0.0

Abstract Reservoir-building on rivers is still “the Brazilian energy culture”, such that many other dams are being constructed and planned, with many other rivers potentially suffering the same impact in their sediment flux. In this study, we evaluated the impacts of reservoir-building on the erosion of the São Francisco, Jequitinhonha, Doce, and Paraíba do Sul river deltas. A time series of Landsat images from 1973 to 2020 was analyzed, with three key highlighted moments (1973, 1997 and 2020) that summarize the erosion processes on these deltas. In addition to the images, continuous river water discharge, sediment discharge and basin rainfall data were analyzed between 1940 and 2020, providing river parameters over a period exceeding that of the satellite data. The findings suggest that coastal erosion has progressed in the four deltas, with higher estimated losses in the São Francisco and Paraíba do Sul over the 47 years of available satellite images. However, despite minimal overall estimated gains, the Jequitinhonha and Doce experienced high erosion at their river mouths, as in the other two rivers, compensated by accretion in distal coastal areas. These results can be explained by reductions in river flux and consequent sediment transport capacity due to reservoirs. Reservoirbuilding Reservoir building culture, culture , culture” planned study reservoirbuilding reservoir deltas 197 202 1973, (1973 199 194 4 However gains mouths areas reservoirs 19 20 (197 1 2 (19 (1 (

Resumen El objetivo principal de este artículo es cuantificar las tasas de erosión y acreción en el margen oriental del estuario medio del Pará en 32 años (1987; 1993; 1999; 2004; 2008; 2013 y 2019) con el uso de sensores remotos y extensión del Sistema Digital de Análisis de Costas (DSAS) de datos. Estos procedimientos metodológicos recientemente aplicados en la región amazónica son efectivos en la búsqueda de los resultados esperados. Para calcular con una precisión significativa las tasas de cambios de LC, seleccione los parámetros Net Shoreline Movement (NSM), Linear Regression Rate (LRR) y End Point Rate (EPR) para obtener las variaciones. En el estuario medio, las tasas tendieron a una retracción de la LC en dirección tierra adentro, con una tasa promedio de −38m y una tasa de acreción promedio de 22,97 m predominando en Ilha de Mosqueiro, relacionado con tasas de variación promedio de −0,58 m /año (EPR) y −0,54 m/año (LRR) y en Santo Antônio do Tauá con parámetros LRR y EPR identificando tasas de variación promedio de −1,67 m/año (LRR) y −1,55 m/año (EPR). Solo en la isla de Colares se presentó una tendencia a la acreción, con una tasa de erosión promedio de −96.29 m y una tasa de acreción promedio de 116.49 m, donde la tasa máxima de acreción y erosión son 405.61 m y −396.87 m, respectivamente. 3 1987 (1987 1993 1999 2004 2008 201 2019 DSAS (DSAS datos esperados NSM, NSM , (NSM) (LRR (EPR variaciones adentro 38m 2297 22 97 22,9 Mosqueiro 058 0 58 −0,5 año 054 54 maño 167 1 67 −1,6 155 55 −1,5 EPR. . 9629 96 29 −96.2 11649 116 49 116.4 40561 405 61 405.6 39687 396 87 −396.8 respectivamente 198 (198 199 200 20 (NSM 229 2 9 22, 05 5 −0, 16 6 −1, 15 962 −96. 1164 11 4 116. 4056 40 405. 3968 39 8 −396. 19 (19 −0 −1 −96 −396 (1 − −9 −39 ( −3

Abstract The main objective of this article is to quantify the erosion and accretion rates on the eastern margin of the middle Pará Estuary within 32 years (1987, 1993, 1999, 2004, 2008, 2013, and 2019) with the use of remote sensing and data Digital Shoreline Analysis System (DSAS) extension. These methodological procedures recently applied in the Amazon region are effective in the search for intended results. To calculate with significant accuracy the rates of CL changes, select the parameters Net Shoreline Movement (NSM), Linear Regression Rate (LRR), and End Point Rate (EPR) to obtain the variations. In the middle estuary, the rates showed a tendency towards CL retreat in the onshore direction, with an average rate of −38 m and an average accretion rate of 22.97 m prevailing on Mosqueiro Island, related to average rates of variation of −0.58 m/ year (EPR) and −0.54 m/year (LRR) and in Santo Antônio do Tauá with LRR and EPR parameters identifying average rates of variation of −1.67 m/year (LRR) and −1.55 m/year (EPR). Only on Colares island, there was a tendency to accretion, with an average erosion rate of −96.29 m and an average accretion rate of 116.49 m, where the maximum accretion and erosion rates are 405.61 m and −396.87 m, respectively. 3 1987, 1987 (1987 1993 1999 2004 2008 2013 2019 DSAS (DSAS extension results changes NSM, NSM , (NSM) LRR, (EPR variations estuary direction 38 −3 2297 22 97 22.9 Island 058 0 58 −0.5 054 54 myear (LRR 167 1 67 −1.6 155 55 −1.5 EPR. . island 9629 96 29 −96.2 11649 116 49 116.4 40561 405 61 405.6 39687 396 87 −396.8 respectively 198 (198 199 200 201 (NSM − 229 2 9 22. 05 5 −0. 16 6 −1. 15 962 −96. 1164 11 4 116. 4056 40 405. 3968 39 8 −396. 19 (19 20 −0 −1 −96 −396 (1 −9 −39 (

Resumo O principal objetivo desse artigo é quantificar as taxas de erosão e de acreção na margem leste do Estuário médio do Pará no decorrer de 32 anos (1987; 1993; 1999; 2004; 2008; 2013 e 2019) com a utilização do sensoriamento remoto e da extensão Digital Shoreline Analysis System (DSAS). Esses procedimentos metodológicos recentemente aplicados na região amazônica se mostraram eficazes na busca dos resultados pretendidos. Para calcular com acurácia significativa as taxas de mudanças da LC foram selecionadas os parâmetros Net Shoreline Movement (NSM), Linear Regression Rate (LRR) e End Point Rate (EPR) para a compreensão das variações. No estuário médio, as taxas apresentaram uma tendência à retração da LC em sentido onshore, predominando na Ilha de Mosqueiro uma taxa média de −38 m e taxa média de acreção de 22,97 m, relacionados às taxas médias de variação de −0,58 m/ano (EPR) e −0,54 m/ano (LRR) e em Santo Antônio do Tauá com LRR e EPR identificando taxas médias de variação de −1,67 m/ano (LRR) e −1,55 m/ano (EPR). Apenas na ilha de Colares houve tendência a acreção, com taxa média de erosão de −96,29 m e taxa média de acreção de 116,49 m, onde a taxa máxima de acreção e de erosão, são de 405,61 m e −396,87 m, respectivamente. 3 1987 (1987 1993 1999 2004 2008 201 2019 DSAS. DSAS . (DSAS) pretendidos NSM, NSM , (NSM) (LRR (EPR variações onshore 38 −3 2297 22 97 22,9 058 0 58 −0,5 mano ano 054 54 167 1 67 −1,6 155 55 −1,5 EPR. 9629 96 29 −96,2 11649 116 49 116,4 40561 405 61 405,6 39687 396 87 −396,8 respectivamente 198 (198 199 200 20 (DSAS (NSM − 229 2 9 22, 05 5 −0, 16 6 −1, 15 962 −96, 1164 11 4 116, 4056 40 405, 3968 39 8 −396, 19 (19 −0 −1 −96 −396 (1 −9 −39 (

Abstract The three-dimensional variability of the subaerial beach is examined for Stanwell Park Beach, New South Wales (NSW), Australia. This embayed environment has previously been studied over long time scales (decades), but not over shorter time scales (days, weeks). Embayed beaches experience rotation events during which opposite accretion and erosion patterns are observed at the extremities of the beach. To analyse this phenomenon, the beach is mapped with 10 Real-Time Kinematic Global Positioning System (RTK-GPS) surveys collected from 10th February 2016 to 14th May 2016. This study aims to examine short-term changes (days, weeks) to the morphology of the subaerial beach of Stanwell Park Beach and any factors that may influence its behaviours. We show that a short-time beach rotation event occurs over one month, caused by a large eastern swell. However, swell with a southern direction generates rip current channels on the subaerial beach face. During this particular event, the amount of sediment transported is lower than during beach rotation events. Furthermore, Stanwell Park Beach has two lagoons that can open to discharge water accumulated in these lagoons. We show that during heavy rainfall, the lagoons open, transporting sediment in surf zone and thus causing erosion. This study provides a clear demonstration of the sensitivity of embayed beaches to short-term variability in wave climate. threedimensional three dimensional NSW, NSW , (NSW) Australia decades, decades (decades) days, days (days weeks. weeks . phenomenon 1 RealTime Real Time RTKGPS RTK GPS (RTK-GPS th 201 shortterm short term behaviours shorttime month However face Furthermore rainfall climate (NSW (decades 20 2

One of the most significant consequences of the global climate crisis is that the rate at which sea levels are rising has accelerated over the past 100 years and will continue to do so for the next century. The accelerated rise in the global mean sea level will inevitably affect the rights and interests of the owners and occupiers of coastal land, especially of coastal land that is bounded by the high-water mark (agri non limitati). This is because changes in the location of the high-water mark brought about by rising sea levels will result either in the acquisition of coastal property where the high-water mark moves seaward or in the loss of coastal property where the high-water mark moves landward. The law relating to the loss or acquisition of coastal property as a result of changes in the location of the high-water mark may be traced back to the common law principles governing the acquisition of ownership by alluvion (alluvio) and the loss of ownership by erosion. As part of an attempt to address the consequences of sea level rise, section 14(5) of the National Environmental: Integrated Coastal Management Act 24 of 2008 has amended some of these common law principles. The purpose of this article is to set out and critically analyse the provisions of section 14(5).

ABSTRACT The temperature predicted by photoionization models for the narrow line region of Seyfert 2 galaxies is lower than the value inferred from the observed [O III]λ4363Å/λ5007 Å line ratio. We explore the possibility of considering a harder ionizing continuum than typically assumed. The spectral ionizing energy distribution, which can generate the observed λ4363 Å/λ5007 Å ratio, is characterized by a secondary continuum peak at 200 eV.

RESUMEN La temperatura predicha por modelos de fotoionización de la región de líneas angostas (NLR) es inferior al valor deducido por el cociente de líneas [O III]λ4363Å/λ5007 Å que se observa en galaxias Seyfert 2. Exploramos la posibilidad de un continuo ionizante mucho más duro que el que t´ıpicamente se usa. La distribución de energía espectral ionizante que logra reproducir el cociente de λ4363 Å/λ5007 Å observado se caracteriza por un segundo pico en el continuo a 200 eV.

ABSTRACT In the context of supermassive black holes and their host galaxies, we consider two scaling relations: M• − R e σ3 and M• − MG σ2, to derive three fundamental parameters for the supermassive black hole at the center of M87. In this paper we will get predictions for the efficiency and mass of the black hole, and the temperature of its accretion disk, by comparing them with the respective experimental values.

RESUMEN En el contexto de los hoyos negros supermasivos y sus galaxias anfitrionas consideramos dos relaciones de escala: M • − Re σ3 y M• − MG σ2, para obtener tres parámetros fundamentales del hoyo negro supermasivo en el centro de M87. En este trabajo, al compararlas con los valores experimentales respectivos, obtenemos predicciones para la eficiencia y la masa del hoyo negro, así como para la temperatura del disco de acreción.

Resumen En las últimas décadas se ha observado un incremento en los efectos erosivos en las costas, lo cual pone en riesgo las infraestructuras y el paisaje del entorno. El departamento del Atlántico (Colombia) no es ajeno a esta repercusión. Se llevó a cabo un estudio de los distintos factores que influyen en las tasas de erosión y de acreción en la zona costera con base en las características hidrodinámicas y de transporte potencial longitudinal de sedimentos (TPLS). Los datos del TPLS se consiguieron mediante dos ecuaciones propuestas por CERC y Kamphuis, cuyos parámetros a escala interanual, intraestacional y anual, están influenciados por el oleaje. Los cambios multitemporales de las líneas de costa del departamento del Atlántico se evaluaron con la herramienta del DSAS (Digital Shoreline Analysis System). Los resultados del Linear Regression Rate (LRR) y End Point Rate (EPR), suministrados por el DSAS, evidencian que los municipios de Barranquilla, Puerto Colombia y Tubará tienen porcentajes de erosión del 40% al 50%, por lo que se concluye que gran parte de la costa del Atlántico se encuentra en procesos erosivos. Finalmente, la ecuación de Kamphuis identifica una similitud con los resultados de la erosión y de acreción en las 8 playas del área de estudio, por lo cual las variables más significativas son la pendiente, la granulometría y la altura de ola.

Abstract In recent decades, there has been an increase in the erosive effects on the coasts, which puts at risk the infrastructures and the surrounding landscape. The department of Atlántico (Colombia) is not immune to this repercussion. A study of the different factors that influence erosion and accretion rates in the coastal zone was carried out based on the hydrodynamic characteristics and the Longitudinal Potential Transport of Sediments (TPLS). The TPLS data were obtained using two equations proposed by CERC and Kamphuis, whose parameters at interannual, intraseasonal and annual scales are influenced by waves. The multi-temporal changes in the coastlines of the department of Atlántico were evaluated with the DSAS (Digital Shoreline Analysis System) tool. The results of the Linear Regression Rate (LRR) and End Point Rate supplied by DSAS show that the Barranquilla, Puerto Colombia, and Tubara areas have erosion percentages of 40% to 50%; therefore, it can be concluded that a large part of the Atlantic coast is in erosion processes. Finally, the equation of Kamphuis identifies a similarity with the results of erosion and accretion in the eight beaches of the study area, for which the most significant variables are: slope, granulometry and wave height.

RESUMEN. El presente artículo analiza la forma en que la Sala Civil de Casación Civil de la Corte Suprema de Justicia realizó la liquidación del lucro cesante con acrecimiento en la sentencia SC4703 del 22 de octubre de 2021, y se pondrán de presente las imprecisiones: omisión de aplicación del acrecimiento durante el lucro cesante consolidado y el equivocado descuento de gastos personales cuando solamente reclama una víctima indirecta, todo lo cual generó un enriquecimiento para la víctima.

ABSTRACT. This article analyzes the way in which the Civil Cassation Chamber of the Supreme Court of Justice carried out the liquidation of lost profits with an accretion in judgment SC4703 of October 22, 2021, where the inaccuracies will be presented: omission of application of the accrual during the consolidated loss of earnings and the wrong deduction of personal expenses when only an indirect victim claims, which generated an enrichment for the victim.

Resumen Al no existir metodologías estandarizadas para el diseño del fluido de perforación en función de caracterización de la roca, revisión de fluidos de pozos de referencia, interacción roca-fluido, nuestro objetivo es obtener la mejor formulación en cada sección, que es específica para cada campo, la que debe ser compatible con las formaciones en las que se están perforando. Metodológicamente se describen los pasos para obtener la mejor formulación compatible con las formaciones en las que se están perforando; caracteriza las rocas de las formaciones geológicas como son: terciario indiferenciado, Orteguaza, Tiyuyacu, Tena y Napo, distribuidas en tres secciones 16”, 12 ¼” y 8 ½”, mediante parámetros: tiempo de succión capilar, capacidad de intercambio catiónico, erosión/dispersión, acreción e hinchamiento lineal, los mismos proporcionan información de reactividad de la formación, posterior selección de formulaciones en pozos de referencia y evaluación en pruebas de interacción roca fluido. Los resultados establecieron un parámetro para evaluar y categorizar el desempeño de la prueba según la contribución al desempeño del fluido, la tecnología, la precisión y la repetibilidad de la prueba, siendo 1 la menor prioridad y 3 la mayor prioridad.

Abstract As there are no standardized methodologies for drilling fluid design based on rock characterization, reference well fluid review, rock-fluid interaction, our goal is to obtain the best formulation in each section, which is specific to each field, which must be compatible with the formations being drilled. Methodologically, the steps to obtain the best formulation compatible with the formations in which they are drilling are described; characterizes the rocks of geological formations such as: undifferentiated tertiary, Orteguaza, Tiyuyacu, Tena and Napo, distributed in three sections 16”, 12 ¼” and 8 ½”, through parameters: capillary suction time, cation exchange capacity, erosion /dispersion, accretion and linear swelling, they provide information on the reactivity of the formation, subsequent selection of formulations in reference wells and evaluation in rock-fluid interaction tests. The results established a parameter to evaluate and rank test performance based on contribution to fluid performance, technology, accuracy, and test repeatability, with 1 being the lowest priority and 3 being the highest priority.

ABSTRACT We present a model for the “Bondi-Hoyle tail” left behind by the hypersonic passage of a compact, massive object through a dense, radiative environment. We derive simple equations for the flow velocity and the mass along the tail, and obtain numerical and approximate analytical solutions for the steady state problem. We then study a time-dependent problem in which the source first travels within a dense cloud, and then emerges into a low density environment. This flow results in the production of a trail of dense gas joining the source at the point in which it emerged from the dense cloud. This trail has a linear velocity vs. position profile.

RESUMEN Presentamos un modelo para una “cola de Bondi-Hoyle” producida por el pasaje hipersónico de un objeto compacto masivo a través de un medio ambiente radiativo. Derivamos ecuaciones sencillas para la velocidad y la masa del flujo a lo largo de la cola, y obtenemos soluciones numéricas y analíticas aproximadas del problema estacionario. Luego estudiamos el problema con dependencia temporal de una fuente que primero viaja dentro de una nube densa y luego emerge a un medio ambiente de baja densidad. Este flujo tiene como resultado la producción de una estela que conecta la fuente con el punto del cual ésta emergió de la nube densa. Esta estela tiene una velocidad que depende linealmente de la posición.