Análisis del conocimiento en la relación agua-suelo-vegetación para el Departamento de Antioquia

En el artículo se presenta una recopilación de los principales resultados obtenidos en el departamento de Antioquia acerca de las interacciones entre el agua, el suelo y la vegetación. Aunque existe conocimiento avanzado en algunos aspectos de esta relación, es necesario profundizar en otros que no han sido abordados de manera integral. Del mismo modo, es necesario ampliar la investigación para cubrir la diversidad de ecosistemas del departamento.This paper presents a compilation of the main results obtained in the Antioquia Department about the interactions between water, soil, and vegetation. Although there is an advanced knowledge in some aspects of this relationship, it is necessary to go deep into other ones which have not been approached in an integral manner. Likewise, it is necessary to enhance the research in order to cover the diversity of ecosystems of the Department

The inversion of spectral ratio H/V in a layered system using the Diffuse Field Assumption (DFA)

In order to evaluate the site effects on seismic ground motion and establish preventive measures to mitigate these effects, the dynamic characterization of sites is mandatory. Among the various geophysical tools aimed to this end, the horizontal to vertical spectral ratio (H/V) is a simple way to assess the dominant frequency of a site from seismic ambient noise. The aim of this communication is contributing to enhance the potential of this measurement with a novel method that allows extracting from the H/V the elastic properties of the subsoil, assumed here as a multilayer medium. For that purpose, we adopt the Diffuse Field Assumption from both the experimental and the modeling perspectives. At the experimental end, the idea is to define general criteria that make the data processing closely supported by theory. On the modeling front, the challenge is to compute efficiently the imaginary part of Green’s function. The Cauchy’s residue theory in the horizontal wavenumber complex plane is the selected approach. This method allows both identifying the contributions of body and surface waves and computing them separately. This permits exploring the theoretical properties of the H/V under different compositions of the seismic ambient noise. This answers some questions that historically aroused and gives new insights into the H/V method. The efficient forward calculation is the prime ingredient of an inversion scheme based on both gradient and heuristic searches. The availability of efficient forward calculation of H/V allows exploring some relevant relationships between the H/V curves and the parameters. This allows generating useful criteria to speed up inversion. As in many inverse problems, the non-uniqueness issues also emerge here. A joint inversion method that considers also the dispersion curves of surface waves extracted from seismic ambient noise is presented and applied to experimental data. This joint scheme mitigates effectively the non-uniqueness

Recuperando la función endotelial

Atherosclerosis starts early in life. The presence of risk factors like hypertension, smoking, dyslipidemia and diabetes as well as obesity and metabolic syndrome accelerates its progress. These factors generate endothelial dysfunction, oxidative stress and inflammation, with early appearance of foamy cells, fatty streaks and atheromatous plaques. These plaques are vulnerable to erosion and rupture, the so called atherothrombotic phenomenon, leading to acute vascular events like acute coronary or cerebrovascular syndromes. Managing and treating the metabolic syndrome, early markers of cardiovascular risk, could slow down end organ aging and damage, probably without reduction of mortality but focusing on three fundamental aspects of early detection of subclinical atherothrombosis: prevention of cardiovascular events, protection of end organs, and improvement of quality of life.La enfermedad ateroesclerótica comienza a temprana edad. La presencia de factores de riesgo, como la hipertensión arterial, tabaquismo, dislipidemia y diabetes mellitus, a lo que hoy se suman la obesidad y el síndrome metabólico, originan desde el inicio disfunción endotelial, incremento del estrés oxidativo e inflamación, con aparición temprana de células espumosas, estrías grasas y placas de ateroma. Placas que en algunos de los casos son consideradas vulnerables, con un riesgo de sufrir erosión y rotura, el fenómeno aterotrombótico y un evento vascular agudo, como el síndrome coronario agudo y el accidente cerebrovascular. Al manejar y tratar los factores de riesgo cardiovasculares, síndrome metabólico, marcadores precoces del riesgo cardiovascular, se podría enlentecer o retardar el envejecimiento (injuria endotelial) de los órganos blanco, probablemente sin reducción de la mortalidad, pero logrando tres enfoques fundamentales con la detección temprana de la aterotrombosis subclínica: prevenir eventos cardiovasculares, brindar protección de los órganos blanco y mejorar la calidad de vida

Bayesian parameter estimation for space and time interacting earthquake rupture model using historical and physics-based simulated earthquake catalogs

This paper presents a robust parameter estimation technique for a probabilistic earthquake hazard model that captures time and space interactions between earthquake mainshocks. The approach addresses the existing limitations of parameter estimation techniques by developing a Bayesian formulation and leveraging physics-based simulated synthetic catalogs to expand the limited datasets of historical catalogs. The technique is based on a two-step Bayesian update that uses the synthetic catalog to perform a first parameter estimation and then uses the historical catalog to further calibrate the parameters. We applied this technique to analyze the occurrence of large-magnitude interface earthquakes along 650 km of the central subduction zone in Peru, located offshore of Lima. We built 2,000-years-long synthetic catalogs using quasi-dynamic earthquake cycle simulations based on the rate-and-state friction law. The validity of the synthetic catalogs was verified by comparing their annual magnitude exceedence rates to those of recorded seismicity and their predicted areas of high interseismic coupling to those inferred from geodetic data. We show that when the Bayesian update uses the combination of synthetic and historical data, instead of only the historical data, it reduces the uncertainty of model parameter estimates by 45% on average. Further, our results show that the time-dependent seismic hazard estimated with the both datasets is 40% smaller than the one estimated with only the historical data

Bayesian parameter estimation for space and time interacting earthquake rupture model using historical and physics-based simulated earthquake catalogs

This paper presents a robust parameter estimation technique for a probabilistic earthquake hazard model that captures time and space interactions between earthquake mainshocks. The approach addresses the existing limitations of parameter estimation techniques by developing a Bayesian formulation and leveraging physics-based simulated synthetic catalogs to expand the limited datasets of historical catalogs. The technique is based on a two-step Bayesian update that uses the synthetic catalog to perform a first parameter estimation and then uses the historical catalog to further calibrate the parameters. We applied this technique to analyze the occurrence of large-magnitude interface earthquakes along 650 km of the central subduction zone in Peru, located offshore of Lima. We built 2,000-years-long synthetic catalogs using quasi-dynamic earthquake cycle simulations based on the rate-and-state friction law. The validity of the synthetic catalogs was verified by comparing their annual magnitude exceedence rates to those of recorded seismicity and their predicted areas of high interseismic coupling to those inferred from geodetic data. We show that when the Bayesian update uses the combination of synthetic and historical data, instead of only the historical data, it reduces the uncertainty of model parameter estimates by 45% on average. Further, our results show that the time-dependent seismic hazard estimated with the both datasets is 40% smaller than the one estimated with only the historical data

Prevalence of orthostatic hypotension in a series of elderly Mexican institutionalized patients

Background: Orthostatic hypotension (OH) is a common problem among the elderly. It is associated with an increase in morbidity and mortality, but its prevalence in Mexico is unknown. Methods: We conducted a cross-sectional prospective study of intern patients at several Mexican elderly assistance institutions. We carried out a history and took blood pressure readings in a seated position, immediately after standing up, and again after 3 min of standing up. Results: We evaluated 132 patients, mean age 82.3 ± 9.5 years, 74.1% of them female. Thirty-nine (29.3%) subjects had OH. They had a higher prevalence of hypothyroidism, Parkinson’s disease, depression and alcoholism. Their Minimental result was 15.45 ± 7.2 vs 16.12 ± 7.9 (p = 0.6) among those without OH, and their quality of life (Minnesota scale) was 12.1 ± 7.3 vs 9.15 ± 7.05 (p = 0.03). They used more ACEI, digoxin and levothyroxin. Hypertension and alcoholism showed respectively a RR of 2.6 (95% CI 0.9–7.6, p = 0.06) and 3.18 (95% CI 0.96–10.48, p = 0.05) to develop OH. Conclusions: OH was present in 29.3% of the studied population. A third of them had hypertension. The use of different medications does not solely explain OH, so it is necessary to look for different associations. Among those, chronic alcoholism stands out. OH is associated with a poorer quality of life and cognitive performance. OH is asymptomatic in most cases. (Cardiol J 2011; 18, 3: 282–288

Mecanismos Moleculares de Resistencia a Ceftazidima/Avibactam en Aislados Clínicos de Enterobacterales y Pseudomonas aeruginosa en Hospitales Latinoamericanos

Ceftazidima-avibactam (CZA) es la combinación de una cefalosporina de tercera generación y un nuevo inhibidor de β-lactamasas no β-lactámico capaz de inactivar β-lactamasas de clase A, C y algunas D. A partir de una colección de 2.727 aislamientos clínicos de Enterobacterales (n = 2.235) y P. aeruginosa (n = 492) que se recogieron entre 2016 y 2017 de cinco países latinoamericanos, investigamos los mecanismos moleculares de resistencia a CZA de 127 (18/2.235 [0,8%] Enterobacterales y 109/492 [22,1%] P. aeruginosa). En primer lugar, mediante qPCR para detectar la presencia de genes que codifican las carbapenemasas KPC, NDM, VIM, IMP, OXA-48-like y SPM-1, y en segundo lugar, mediante secuenciación del genoma completo (WGS). De los aislados resistentes a la CZA, se detectaron genes codificadores de MBL en los 18 Enterobacterales y los 42/109 aislados de P. aeruginosa, lo que explica su fenotipo resistente. Los aislados resistentes que dieron un resultado negativo en la qPCR para cualquiera de los genes codificadores de MBL se sometieron a WGS. El análisis WGS de los 67 aislados de P. aeruginosa restantes mostró mutaciones en genes previamente asociados con una susceptibilidad reducida a la CZA, como los implicados en la bomba de eflujo MexAB-OprM y la hiperproducción de AmpC (PDC), PoxB (blaOXA-50-like), FtsI (PBP3), DacB (PBP4) y OprD. Los resultados aquí presentados ofrecen una instantánea del panorama epidemiológico molecular para la resistencia a CZA antes de la introducción de este antibiótico en el mercado latinoamericano. Por lo tanto, estos resultados sirven como una valiosa herramienta de comparación para rastrear la evolución de la resistencia a CZA en esta región geográfica endémica de carbapenemasas.Ceftazidime-avibactam (CZA) is the combination of a third-generation cephalosporin and a new non-β-lactam β-lactamase inhibitor capable of inactivating class A, C, and some D β-lactamases. From a collection of 2,727 clinical isolates of Enterobacterales (n = 2,235) and P. aeruginosa (n = 492) that were collected between 2016 and 2017 from five Latin American countries, we investigated the molecular resistance mechanisms to CZA of 127 (18/2,235 [0.8%] Enterobacterales and 109/492 [22.1%] P. aeruginosa). First, by qPCR for the presence of genes encoding KPC, NDM, VIM, IMP, OXA-48-like, and SPM-1 carbapenemases, and second, by whole-genome sequencing (WGS). From the CZA-resistant isolates, MBL-encoding genes were detected in all 18 Enterobacterales and 42/109 P. aeruginosa isolates, explaining their resistant phenotype. Resistant isolates that yielded a negative qPCR result for any of the MBL encoding genes were subjected to WGS. The WGS analysis of the 67 remaining P. aeruginosa isolates showed mutations in genes previously associated with reduced susceptibility to CZA, such as those involved in the MexAB-OprM efflux pump and AmpC (PDC) hyperproduction, PoxB (blaOXA-50-like), FtsI (PBP3), DacB (PBP4), and OprD. The results presented here offer a snapshot of the molecular epidemiological landscape for CZA resistance before the introduction of this antibiotic into the Latin American market. Therefore, these results serve as a valuable comparison tool to trace the evolution of the resistance to CZA in this carbapenemase-endemic geographical region

Comparative In Vitro Activity of Ceftolozane/Tazobactam against Clinical Isolates of Pseudomonas aeruginosa and Enterobacterales from Five Latin American Countries

Background: Ceftolozane/tazobactam (C/T) is a combination of an antipseudomonal oxyiminoaminothiazolyl cephalosporin with potent in vitro activity against Pseudomonas aeruginosa and tazobactam, a known β-lactamase inhibitor. The aim of this study was to evaluate the activity of C/T against clinical isolates of P. aeruginosa and Enterobacterales collected from five Latin American countries between 2016 and 2017, before its clinical use in Latin America, and to compare it with the activity of other available broad-spectrum antimicrobial agents. Methods: a total of 2760 clinical isolates (508 P. aeruginosa and 2252 Enterobacterales) were consecutively collected from 20 hospitals and susceptibility to C/T and comparator agents was tested and interpreted following the current guidelines. Results: according to the CLSI breakpoints, 68.1% (346/508) of P. aeruginosa and 83.9% (1889/2252) of Enterobacterales isolates were susceptible to C/T. Overall, C/T demonstrated higher in vitro activity than currently available cephalosporins, piperacillin/tazobactam and carbapenems when tested against P. aeruginosa, and its performance in vitro was comparable to fosfomycin. When tested against Enterobacterales, it showed higher activity than cephalosporins and piperacillin/tazobactam, and similar activity to ertapenem. Conclusions: these results show that C/T is an active β-lactam agent against clinical isolates of P. aeruginosa and Enterobacterales.Fil: García Betancur, Juan Carlos. Universidad El Bosque;Fil: De La Cadena, Elsa. Universidad El Bosque;Fil: Mojica, María F.. Universidad El Bosque; . Case Western Reserve University; Estados UnidosFil: Hernández Gómez, Cristhian. Universidad El Bosque;Fil: Correa, Adriana. Universidad Santiago de Cali; ColombiaFil: Radice, Marcela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquÍmica. Instituto de Investigaciones En Bacteriología y Virología Molecular (IBaViM); ArgentinaFil: Castañeda Méndez, Paulo. Fundacion Clinica Medica Sur; MéxicoFil: Jaime Villalon, Diego A.. Fundacion Clinica Medica Sur; MéxicoFil: Gales, Ana C.. Universidade Federal de Sao Paulo; BrasilFil: Munita, José M.. Universidad del Desarrollo; ChileFil: Villegas, María Virginia. Universidad El Bosque