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This paper presents the results obtained from using electron paramagnetic resonance (EPR) to analyse tooth enamel found at the Aguazuque archaeological site (Cundinamarca, Colombia), located on the savannah near Bogota at 4° 37' North and 74°17' West. It was presumed that the tooth enamel came from a collective burial consisting of 23 people, involving men, women and children. The tooth enamel was irradiated with gamma rays and the resulting free radicals were measured using an electron spin resonance (ESR) X-band spectrometer to obtain a signal intensity compared to absorbed doses curve. Fitting this curve allowed the mean archaeological dose accumulated in the enamel during the period that it was buried to be estimated, giving a 2.10 ± 0.14 Gyvalue. ROSY software was used for estimating age, giving a mean 3,256 ± 190y before present (BP) age. These results highlight EPR's potential when using the quaternary ancient ruins dating technique in Colombia and its use with other kinds of samples like stalagmites, calcite, mollusc shells and reefs.

Spectral inversion using a genetic algorithm (GA) as an optimisation approach was used for increasing the seismic resolution of a particular dataset; by contrast with the conjugate gradient method, a GA does not require a good starting model but rather a search space.The method discriminated layers thinner than λ/8 when tested on synthetic and log data. When applied to a seismic dataset concerning the Barco formation in the Catatumbo basin, Colombia, spectral inversion led to recovering information from seismic data contributing towards the vertical identification of geological features such as thin distributary channels deposited in a deltaic environment having a tidal influence. The results revealed that a GA outperformed traditional minimisation schemes.

In order to characterize the Caballos formation reservoir in the Orito field in the Putumayo basin - Colombia, a multiattribute analysis was applied to a 50 km2 seismic volume along with 16 boreholes. Some properties of the reservoir were reliably estimated and very accurate when compared with well data. The porosity, permeability and volume of shale were calculated in the seismic volume by at least second order multivariate polynomial. A good correlation between porosity and acoustic impedance was observed by means of crossplot analysis performed on properties measured and estimated in cores or borehole logs as well as on properties calculated in the seismic volume. The estimated property values were well behaved according to the rocks physics analysis. With the property maps generated and the geological environments of the reservoir a new interpretation of the Caballos formation was established. High correlation coefficients and low estimated errors point out competence to calculate these three reservoir properties in places far from the influence of the wells. The multiple equation system was established through weighted hierarchical grouping of attributes and their coefficients calculated applying the inverse generalized matrix method.

We applied the NMO and CRS (Common Reflector Surface) approaches to a complex geological area in order to compare their performances for obtaining enhanced images. Unlike NMO, CRS does not depend on a previous time velocity model and uses a hyperbolic equation to estimate 2D travel times through three parameters (Normal ray emergence angle, NIP and N wavefront curvatures). To obtain the image a solution provided by coherence analysis algorithm was used.A low quality Colombian seismic line acquired in Middle Magdalena basin was used, where a foothill geological area is characterizedby a thrusting fault. The CRS provided an enhanced image which allowed a new geological interpretation that is best constrained with other regional observations.

The AVO analysis is based in variation of amplitude of waves with offset, due mainly to elastic properties of rocks. The variables characterizing the elastic behavior ofrocks, licke velocity of s-waves and attenuation, can be estimated by AVO analysis. This can be considered cheap in case ofland acquisition and possible in case of maxime acquisition. This paper describes a different methodology to use AVO, analyzing the relative change ofthe amplitude use with frequency between two reflectors, recovering the last energy of wave due transmission are conversion of wares affected by the angle of incidence.The method was applica to synthetic data of models with homogeneus and isotropic layers separated by plan-paralled interfaces, models associated to maxime depositation environment with low tectonic activity, with stratigraphic features as seen in wt plans in Colombia.EI análisis AVO se basa en la variación de amplitudes de ondas con el offset, determinada entre otras causas por las propiedades elásticas de las rocas.Las variables necesarias para caracterizar el comportamiento elástico de las rocas, como la velocidad de ondas-s y atenuación, se llegan a determinar mediante análisis AVO. La valoración de velocidades resulta menos costosa en unos casos, cuando el AVO remplaza la utilización de multicomponentes en adquisiciones terrestres, y en otros casos posible, cuando se utiliza a partir de adquisiciones marinas. El presente artículo describe una metodología diferente para la utilización AVO (AVA), que consiste en analizar los cambios relativos de amplitud de onda en frecuencia entre dos reflectores próximos, corrigiendo así pérdidas de energía de la onda por efectos de transmisión y conversión que dependen del ángulo de incidencia.El método se aplicó a datos sintéticos de modelos de capas con interfaces planas y paralelas asociados a los ambientes de depósito principalmente marinos de baja actividad tectónica con cambios principalmente estratigráficos, como por ejemplo en zonas de los llanos orientales de Colombia.

Through finite difference modelling, we studied the effects of seismic scattering due near surface high velocity layers, with varied contrasts and thickness, and their influence on seismic data. Despite conventional methods to eliminate noise mainly based in a mathematical approach, i.e., F-K analysis, Radon transform, we apply a deterministic scheme based on the modeling of wave propagation, generating the unwanted signals (Ernst et al., 1998; Blonk et al., 1995; Blonk and Hermann, 1994).The detailed understanding of the backscattering phenomenon allows to discern what can be considered noise and therefore to define attenuation' s strategies (Lamer et al., 1983). In presence of near surface high velocity layers, part of the original seismic energy is scattered in these layers and only a smaller fraction is transmitted to the Earth' s interior, generating coherent noise that masks the information comming from the deeper reflectors (Leslie and Evans, 1999). A 20 model was designed to obtain synthetic seismograms. The simulation shows the scattering mechanism related with velocity inversions in the near surface layers, allowing to characterize their influence on seismic records. The unwanted signal is subtracted from that considered information. The results obtained in this work are bounded to the analysis of synthetic data.Mediante el modelamiento con diferencias finitas, se estudia el efecto de la dispersion sísmica por la presencia de capas someras de alta velocidad, con contrastes y espesores variables, y su influencia en la información sísmica. A diferencia de los métodos convencionales de eliminacion de ruido de base fundamentalmente matemática, por ejemplo: F-K, Radón, se aplica un esquema determinístico basado en el modelamiento de propagación de ondas que reproduce las señales no deseadas (Ernst et al., 1998; Blonk et al., 1995; Blonk and Hermann, 1994). El entendimiento detallado del fenómeno que genera estas señales permite discernir lo que se considera ruido y, por tanto, definir estrategias para su atenuación (Lamer et al., 1983). Por la presencia de capas someras de alta velocidad, gran parte de la energía sísmica original se dispersa en estas capas y solo una pequeña fracción se transmite al interior de la Tierra, generando ruido coherente que enmascara la información proveniente de los reflectores mas profundos (Leslie and Evans, 1999). Se diseño un modelo 20 y se obtuvieron varios sismogramas sintéticos, La simulación muestra el mecanismo de dispersión relacionado con la inversion de velocidad en las capas mas someras, lo que permite caracterizar su influencia sobre los registros sísmicos. La información no deseada (ruido) es sustraída de la que se considera información. Los resultados obtenidos en este trabajo se circunscriben al análisis de datos sintéticos.

The foothills areas are characterized by low velocity shallow layers and rugged topopgraphy. Inside these stratas a coherent noise named back scattering is produced, that noise overlaps the waves comming from the deeper reflectors. In seismic sections of the colombian foothills this signal is observed, obscuring the subsurface image. A method to attenuate this signal is presented in this paper, the approach is based in the prediction of this noise and the posterior remotion from the seismic records. The shallow layer response is simulated through the numerical modeling in finite elements of the acustic wave propagation in a subsurface model. Lately, the shallow layer response is subtracted trace by trace from the synthetic record, getting a high noise's attenuation in the shot. We present results obtained by synthetic data modeling.Las zonas de piedemonte se caracterizan por las capas someras de baja velocidad y poria topografía rugosa. En esos estratos se produce un ruido coherente lIamado backscattering que apantalla las ondas que provienen de los retlectores profundos. Esta señal se observa en las secciones sísmicas del piedemonte colombiano, oscureciendo la imagen del subsuelo. Para atenuar esta señal, se presenta en este artículo un método basado en la predicción de dicho ruido y su posterior remoción de los registros. Para ello se simula la respuesta de la capa somera mediante el modelamiento numérico en elementos finitos de la propagación de la onda acústica en un modelo del subsuelo. Posteriormente, esta respuesta se sustrae traza por traza del registro sintético, logrando una atenuación sustancial del ruido en el disparo. Se presentan resultados obtenidos de la simulación con datos sintéticos

Although there is a large body of literature examining metropolitan regions, it is difficult to find specific literature on metropolitan planning, especially in Latin America. Few studies overlook the enormous diversity of institutional frameworks in a region that is often considered a homogeneous territory, failing to highlight many planning innovations. This paper aims to investigate the particularity of metropolitan planning in Latin America through a comparative case study of its three largest agglomerations: Greater Buenos Aires, the Valley of Mexico, and the Metropolitan Region of São Paulo. This analysis focuses on the instrumental, institutional, and procedural dimensions of planning. [ABSTRACT FROM AUTHOR]

This opinion article highlights the critical role of laboratory medicine and emerging technologies in cardiovascular risk reduction through exposome analysis. The exposome encompasses all external and internal exposures an individual faces throughout their life, influencing the onset and progression of cardiovascular diseases (CVD). Integrating exposome data with genetic information allows for a comprehensive understanding of the multifactorial causes of CVD, facilitating targeted preventive interventions. Laboratory medicine, enhanced by advanced technologies such as metabolomics and artificial intelligence (AI), plays a pivotal role in identifying and mitigating these exposures. Metabolomics provides detailed insights into metabolic changes triggered by environmental factors, while AI efficiently processes complex datasets to uncover patterns and associations. This integration fosters a proactive approach in public health and personalized medicine, enabling earlier detection and intervention. The article calls for global implementation of exposome technologies to improve population health, emphasizing the need for robust technological platforms and policy-driven initiatives to seamlessly integrate environmental data with clinical diagnostics. By harnessing these innovative technologies, laboratory medicine can significantly contribute to reducing the global burden of cardiovascular diseases through precise and personalized risk mitigation strategies. [ABSTRACT FROM AUTHOR]

Abies guatemalensis Rehder, an endangered conifer endemic to Central American highlands, is ecologically vital in upper montane forests. It faces threats from habitat fragmentation, unsustainable logging, and illegal Christmas tree harvesting. While previous genetic studies on mature trees from eighteen populations showed high within-population diversity and limited among-population differentiation, the genetic impact of recent anthropogenic pressures on younger generations has yet to be discovered. Understanding these effects is crucial for developing effective conservation strategies for this vulnerable species. We sampled 170 young trees (< 15 years old) from seven populations across Guatemala. Seven microsatellite markers were used to analyse genetic diversity, population structure, and recent demographic history. Moderate levels of genetic diversity were observed within populations (mean Shannon diversity index = 4.97, mean Simpson’s index = 0.51, mean allelic richness = 11.59, mean observed heterozygosity = 0.59). Although genetic structure broadly aligned with mountain corridors, substantial admixture patterns suggest historical connectivity across all populations. Most populations showed evidence of recent bottlenecks (p < 0.05) and inbreeding. The results suggest a potential decline in genetic diversity and increased population structuring (ΦST = 0.274, p < 0.01) over the past decades compared to the previous study on old trees. The observed genetic patterns indicate ongoing impacts of habitat fragmentation and anthropogenic pressures on A. guatemalensis. Conservation efforts should prioritise expanding effective population sizes and facilitating gene flow, particularly for isolated populations. While restoration efforts may be logistically easier within mountain ranges, genetic evidence suggests that increasing overall population connectivity could benefit this species. Management strategies should implement systematic seed collection protocols to maintain genetic diversity in future populations. These findings highlight the urgent need for conservation measures to preserve remaining genetic diversity and promote connectivity among A. guatemalensis populations. [ABSTRACT FROM AUTHOR]

Geoscientists commonly focus on Tertiary units to understand the Andean uplift and deformation of the eastern Cordillera of Colombia, whereas the Cretaceous evolution remains poorly known. Cretaceous units are exposed in western Eastern Cordillera, but outcrops are scarce in the Middle Magdalena Valley. Recent seismic acquisition programs and new wells drilled through the Cretaceous succession led to a better understanding of unconformities and sequences in both the Middle Magdalena Valley and the western flank of the Eastern Cordillera.This paper identifies unconformities bounding seismic sequences and deciphers Cretaceous structural deformation in the Middle Magdalena Valley and western Eastern Cordillera based on the interpretation of sizable seismic reflection sections and well information. The analysis of sedimentary sequences and unconformity surfaces allowed identification of stages of pre-Eocene deformation. Regional correlations of sequences and unconformities recognized here with those identified by other authors support the occurrence of Cretaceous regional tectonic events.

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Copyright of Agora (0211-6642) is the property of Universidad de Santiago de Compostela, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)