Implications of dietary carbon incorporation in fish carbonates for the global carbon cycle.

Marine bony fish are important participants in Earth's carbon cycle through their contributions to the biological pump and the marine inorganic carbon cycle. However, uncertainties in the composition and magnitude of fish contributions preclude their integration into fully coupled carbon-climate models. Here, we consider recent upwards revisions to global fish biomass estimates (2.7-9.5×) and provide new stable carbon isotope measurements that show marine fish are prodigious producers of carbonate with unique composition. Assuming the median increase (4.17×) in fish biomass estimates is linearly reflected in fish carbonate (ichthyocarbonate) production rate, marine fish are estimated to produce between 1.43 and 3.99 Pg CaCO3 yr-1, but potentially as much as 9.03 Pg CaCO3 yr-1. Thus, marine fish carbonate production is equivalent to or potentially higher than contributions by coccolithophores or pelagic foraminifera. New stable carbon isotope analyses indicate that a significant proportion of ichthyocarbonate is derived from dietary carbon, rather than seawater dissolved inorganic carbon. Using a statistical mixing model to derive source contributions, we estimate ichthyocarbonate contains up to 81 % dietary carbon, with average compositions of 28-56 %, standing in contrast to contents <10 % in other biogenic carbonate minerals. Results also indicate ichthyocarbonate contains 5.5-40.4 % total organic carbon. When scaled to the median revised global production of ichthyocarbonate, an additional 0.08 to 1.61 Pg C yr-1 can potentially be added to estimates of fish contributions to the biological pump, significantly increasing marine fish contributions to total surface carbon export. Our integration of geochemical and physiological analyses identifies an overlooked link between carbonate production and the biological pump. Since ichthyocarbonate production is anticipated to increase with climate change scenarios, due to ocean warming and acidification, these results emphasize the importance of quantitative understanding of the multifaceted role of marine fish in the global carbon cycle.

Microscopic analysis of the myocardial bridges and their relationship with atheromatous plaque / Análisis microscópico de los puentes miocárdicos y su relación con la placa ateromatosa

SUMMARY: Most histopathological studies have reported that the segment of the coronary artery below the myocardial bridge does not present atheromatous plaque, while the segment proximal to the myocardial bridge may have it. The aim of this study was to evaluate the microscopic environment of myocardial bridges. This descriptive study was carried out with 60 hearts of individuals who underwent autopsy at the National Institute of Legal Medicine and Forensic Sciences in Bucaramanga-Colombia. For each specimen, the coronary arteries and their branches were dissected, removing the subepicardial adipose tissue to identify the myocardial bridges and obtain histological sections of the compromised arterial branches. The presence of myocardial bridges was observed in 22 hearts (36.7%) with a length of 17.31 + 4.41 mm and a thickness of 904.57 + 312.27 mm. The coronary vessel caliber at the prepontine level was 246.57 + 49.33 mm and was significantly higher than in the pontine (188.92 + 60.55 mm) and postpontin (190.40 + 47 mm) segments (p=0.001 for both values). Atheromatous plaque was observed in the prepontine segment in 12 cases (46.15 %) and in 8 samples (30.76%) at the pontine level, but in this segment, there was slight damage to the vascular endothelium, or phase I level. The thickness of the tunica intima in the cases with atheromatous plaque was 15.68 + 13.39 mm and that of the plaque-free segments was 5.10 + 4.40 mm (p=0.005), and in the pontine segment the overlying periarterial adipose tissue had a thickness of 72.01 + 69.44 mm, which was higher than the other three locations (p=0.005). The morphometry of the perivascular fat pad and the presence of phase I atheromatous plaque are the main contributions of this study to the histology of myocardial bridges.

RESUMEN: La mayoría de los estudios histopatológicos han reportado que el segmento de la arteria coronaria debajo del puente miocárdico no presenta placa ateromatosa, mientras que el segmento proximal al puente miocárdico puede tenerla. El objetivo de este estudio fue evaluar el entorno microscópico de los puentes miocárdico. Este estudio descriptivo se realizó con 60 corazones de individuos a quienes se les práctico autopsia en el Instituto Nacional de Medicina Legal y Ciencias Forenses de Bucaramanga-Colombia. Para cada espécimen se realizó disección de las arterias coronarias y sus ramas, eliminando el tejido adiposo subepicárdico para identificar los puentes miocárdicos y obtener secciones histológicas de las ramas arteriales comprometidas. Se observó presencia de puentes miocárdicos en 22 corazones (36,7 %) con una longitud de 17.31 + 4.41 mm y un espesor de 904.57 + 312.27 mm. El calibre del vaso coronario a nivel prepontino fue 246.57 + 49.33 mm y fue significativamente mayor que en el segmento pontino (188.92 + 60.55 mm) y pospontino (190.40 + 47 mm) (p=0.001 para ambos valores). Se observó placa ateromatosa en el segmento prepontino en 12 casos (46.15 %) y en 8 muestras (30.76%) al nivel pontino, pero en este segmento, correspondieron a fase I, con ligero daño en el endotelio vascular. El espesor de la túnica íntima en los casos con placa ateromatosa fue de 15.68 + 13.39 mm y de los segmentos libres de placa fue 5.10 + 4.40 mm (p=0.005) y en el segmento pontino el tejido adiposo periarterial suprayacente presento un espesor de 72.01 + 69.44 mm, el cual fue mayor a las otras tres ubicaciones (p=0.005). La morfometría de la almohadilla adiposa perivascular y la presencia de placa ateromatosa en fase I son los principales aportes de este estudio a la histología de los puentes miocárdicos.

ENSO-induced co-variability of Salinity, Plankton Biomass and Coastal Currents in the Northern Gulf of Mexico.

The northern Gulf of Mexico (GoM) is a region strongly influenced by river discharges of freshwater and nutrients, which promote a highly productive coastal ecosystem that host commercially valuable marine species. A variety of climate and weather processes could potentially influence the river discharges into the northern GoM. However, their impacts on the coastal ecosystem remain poorly described. By using a regional ocean-biogeochemical model, complemented with satellite and in situ observations, here we show that El Niño - Southern Oscillation (ENSO) is a main driver of the interannual variability in salinity and plankton biomass during winter and spring. Composite analysis of salinity and plankton biomass anomalies shows a strong asymmetry between El Niño and La Niña impacts, with much larger amplitude and broader areas affected during El Niño conditions. Further analysis of the model simulation reveals significant coastal circulation anomalies driven by changes in salinity and winds. The coastal circulation anomalies in turn largely determine the spatial extent and distribution of the ENSO-induced plankton biomass variability. These findings highlight that ENSO-induced changes in salinity, plankton biomass, and coastal circulation across the northern GoM are closely interlinked and may significantly impact the abundance and distribution of fish and invertebrates.

Morphological characterization of the renal vein in pigs (Sus domesticus). Differential analysis with the human renal veins

Despite its importance as an experimental model, information about the morphology of the renal vein (RV) is scarce and limited to qualitative descriptions. The objective of this investigation was to determine the morphological characteristics of the RV and its tributaries in pigs (Sus domesticus). We studied 93 pairs of kidneys of pigs destined to slaughter. This descriptive study evaluated the RV and its tributaries, which were perfused with polyester resin (85% Palatal and 15% styrene). Subsequently for full corrosion pieces were subjected to infusion of KOH (potassium hydroxide) for 10 days. The RV and their tributaries were assessed for shape, trajectory and morphometry. The level of significance was set at p< 0.05. A single RV was found in 93% of the specimens. The caliber of the RV was 12.8±3.05 mm. It was significantly higher on the left side (p=0.043). Length was 26.54±12.81 mm for the right RV and 37.64±13.62 mm for the left RV. The position of the RV in relation with the renal artery was cranial-ventral in 46.2% of the specimens, whereas its origin was hilar in 61.9% of the cases. The emergence of the RV from two tributary veins (pattern Ia) was the most common (76.9%). The morphological characteristics of the VR observed in this study are similar to those reported in humans, so the usefulness of this animal model in procedural applications and hemodynamics is evident

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Morphological expression of the pig coronary sinus and its tributaries: a comparative analysis with the human heart

The objective of this study was to determine the morphological expression of the coronary sinus and its tributary branches in pigs. This descriptive cross-over study evaluated continuous variables with t test, and discrete variables with the Pearson χ square test. A level of significance p <0.05 was used. The coronary sinus (CS) and its tributaries were perfused with polyester resin (Palatal 85%, Styrene 15%), and then the hearts were subjected to KOH infusion to release subepicardal fat. The shape, trajectory and morphometry of the CS and its tributary veins were assessed. The CS was 26.9 ± 5.69 mm in length, with a proximal caliber of 10.8 ± 2.43 mm. It was cylindrical in shape in 69% of cases. The left marginal had a distal caliber of 2.6 ± 0.75 mm. The distal caliber of the middle cardiac vein (MCV) was 3.7 ± 1.04 mm. An anastomosis between the venous branches was observed in 63% of hearts. The caliber of the minor cardiac vein and the left azygous vein was 1.67 ± 0.49 mm and 8.47 ± 2.07, mm respectively. The distal caliber of the right marginal vein was 1.54 ± 0.28 mm. Myocardial bridges over the MCV were found in 10 cases (8%). A greater frequency of anastomoses was observed at the level of the heart apex between the MCV and the great cardiac vein than described in human studies. Because human and swine hearts exhibit similarity in the pattern of the CS and its tributaries, this animal model is suitable for performing procedural and hemodynamic applications

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Modelación 3-D para análisis e instrumentación sísmica de la represa La Plata, Puerto Rico

El presente trabajo propone una manera analítica de identificar la localización más adecuada para localizar la instrumentación de Movimiento Fuerte en la represa La Plata en Toa Alta, Puerto Rico. Un modelo tridimensional de elementos finitos fue desarrollado considerando la estructura (represa), el efecto estático y dinámico del agua y el suelo bajo su fundación. Pruebas sencillas para obtener las propiedades dinámicas del concreto y la roca fueron implementadas en el sitio. Tres modelos fueron definidos a través de relaciones de módulos entre el hormigón y la roca de 1, 3.7 y 12.4. Los análisis de los modelos fueron desarrollados en el dominio del tiempo usando un registro artificial de aceleraciones diseñado para la región y diferentes valores de amortiguamiento. Los criterios para localizar la instrumentación fueron: la ubicación de los desplazamientos máximos, la ubicación de las aceleraciones máximas, la captura de los tres primeros modos de vibración de la represa y la aparición del efecto de balanceo (rocking). Dichos puntos estuvieron en general hacia la cresta de la represa en la cercanía del edificio de oficinas. El análisis permitió ubicar la instrumentación de una manera racional y observar la variación de los esfuerzos de tensión en el concreto y aparición de fisuras para las diferentes relaciones de módulos usadas. También se llevo a cabo el trabajo de campo para la instalación de los acelerómetros. (AU)