Low awareness of the transitivity assumption in complex networks of interventions: a systematic survey from 721 network meta-analyses.

BACKGROUND: The transitivity assumption is the cornerstone of network meta-analysis (NMA). Violating transitivity compromises the credibility of the indirect estimates and, by extent, the estimated treatment effects of the comparisons in the network. The present study offers comprehensive empirical evidence on the completeness of reporting and evaluating transitivity in systematic reviews with multiple interventions. METHODS: We screened the datasets of two previous empirical studies, resulting in 361 systematic reviews with NMA published between January 2011 and April 2015. We updated our evidence base with an additional 360 systematic reviews with NMA published between 2016 and 2021, employing a pragmatic approach. We devised assessment criteria for reporting and evaluating transitivity using relevant methodological literature and compared their reporting frequency before and after the PRISMA-NMA statement. RESULTS: Systematic reviews published after PRISMA-NMA were more likely to provide a protocol (odds ratio (OR): 3.94, 95% CI: 2.79-5.64), pre-plan the transitivity evaluation (OR: 3.01, 95% CI: 1.54-6.23), and report the evaluation and results (OR: 2.10, 95% CI: 1.55-2.86) than those before PRISMA-NMA. However, systematic reviews after PRISMA-NMA were less likely to define transitivity (OR: 0.57, 95% CI: 0.42-0.79) and discuss the implications of transitivity (OR: 0.48, 95% CI: 0.27-0.85) than those published before PRISMA-NMA. Most systematic reviews evaluated transitivity statistically than conceptually (40% versus 12% before PRISMA-NMA, and 54% versus 11% after PRISMA-NMA), with consistency evaluation being the most preferred (34% before versus 47% after PRISMA-NMA). One in five reviews inferred the plausibility of the transitivity (22% before versus 18% after PRISMA-NMA), followed by 11% of reviews that found it difficult to judge transitivity due to insufficient data. In justifying their conclusions, reviews considered mostly the comparability of the trials (24% before versus 30% after PRISMA-NMA), followed by the consistency evaluation (23% before versus 16% after PRISMA-NMA). CONCLUSIONS: Overall, there has been a slight improvement in reporting and evaluating transitivity since releasing PRISMA-NMA, particularly in items related to the systematic review report. Nevertheless, there has been limited attention to pre-planning the transitivity evaluation and low awareness of the conceptual evaluation methods that align with the nature of the assumption.

Clinical practice guideline on the use of single-operator cholangioscopy in the diagnosis of indeterminate biliary stricture and the treatment of difficult biliary stones.

BACKGROUND AND AIMS: Single-operator cholangioscopy (SOC) offer a diagnostic and therapeutic alternative with an improved optical resolution over conventional techniques; however, there are no standardized clinical practice guidelines for this technology. This evidence-based guideline from the Colombian Association of Digestive Endoscopy (ACED) intends to support patients, clinicians, and others in decisions about using in adults the SOC compared to endoscopic retrograde cholangiopancreatography (ERCP), to diagnose indeterminate biliary stricture and to manage difficult biliary stones. METHODS: ACED created a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. Universidad de los Andes and the Colombia Grading of Recommendations Assessment, Development and Evaluation (GRADE) Network supported the guideline-development process, updating and performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The GRADE approach was used, including GRADE Evidence-to-Decision frameworks. RESULTS: The panel agreed on one recommendation for adult patients with indeterminate biliary strictures and one for adult patients with difficult biliary stones when comparing SOC versus ERCP. CONCLUSION: For adult patients with indeterminate biliary strictures, the panel made a conditional recommendation for SOC with stricture pattern characterization over ERCP with brushing and/or biopsy for sensitivity, specificity, and procedure success rate outcomes. For the adult patients with difficult biliary stones the panel made conditional recommendation for SOC over ERCP with large-balloon dilation of papilla. Additional research is required on economic estimations of SOC and knowledge translation evaluations to implement SOC intervention in local contexts.

Hydration of Propargyl Esters Catalyzed by Gold(I) Complexes with Phosphoramidite Calix[4]pyrrole Cavitands as Ligands.

We report the synthesis and characterization of two diastereomeric phosphoramidite calix[4]pyrrole cavitands and their corresponding gold(I) complexes, 2in•Au(I)•Cl and 2out•Au(I)•Cl, featuring the metal center directed inward and outward with respect to their aromatic cavity. We studied the catalytic activity of the complexes in the hydration of a series of propargyl esters as the benchmarking reaction. All substrates were equipped with a six-membered ring substituent either lacking or including a polar group featuring different hydrogen bond acceptor (HBA) capabilities. We designed the substrates with the polar group to form 1:1 inclusion complexes of different stabilities with the catalysts. In the case of 2in•Au(I)•OTf, the 1:1 complex placed the alkynyl group of the bound substrate close to the metal center. We compared the obtained results with those of a model phosphoramidite gold(I) complex lacking a calix[4]pyrrole cavity. We found that for all catalysts, the presence of an increasingly polar HBA group in the substrate provoked a decrease in the hydration rate constants. We attributed this result to the competing coordination of the HBA group of the substrate for the Au(I) metal center of the catalysts.

Meckel's diverticulum: analysis of 27 cases in an adult population.

Background: Meckel's diverticulum is a rare congenital pathology among newborns. Nevertheless, it is an uncommon abdominal pathology in the adult population. Therefore, we aim to provide a detailed account of our surgical approach in treating 27 cases of Meckel's diverticulum. Methods: This study is a cross-sectional analysis that utilized a database with prospectively collected data from 2004 to 2022. All patients under the age of 18 were excluded from the population. We described the population's demographic characteristics, symptoms, anatomopathological study, surgical technique, complications, morbidity, and mortality. A subgroup analysis was performed between the symptomatic and asymptomatic patients. Results: A total of 27 patients who underwent surgical resection for a posteriorly diagnosed Meckel's diverticulum were included. The male population accounted for 81.4% (n = 22) of the sample size. The symptomatic group consisted of 18 male and four female patients. Abdominal pain was the predominant symptom in 85% of the patients. Out of the 22 symptomatic patients, only 9% had a positive perioperative diagnosis of Meckel's diverticulum. All 27 patients with diverticulum diagnosis received the resection through diverticulectomy (n = 6), small bowel resection with end-to-end anastomosis (n = 6), and small bowel resection with lateral to lateral anastomosis (n = 15). The mean distance between the diverticulum and the ileocecal valve was 63.4 cm. The symptomatic group had an average diverticulum length of 3.54 cm, with an average base width of 2.47 cm. In the other group, the values were 2.75 and 1.61 cm. The average length of hospital stay in the symptomatic group was 7.3 days. Conclusions: Meckel's diverticulum is a rare pathology in the adult population. Its presentation varies from asymptomatic to symptomatic patients, and surgery is the cornerstone treatment for this pathology.

Potentiometric detection of creatinine in the presence of nicotine: Molecular recognition, sensing and quantification through multivariate regression.

Systematic errors in the calix [4] pyrrole-based potentiometric detection of creatinine have been observed in heavy smokers. This work further characterizes the interactions between the nicotinium cation and the cavitand as well as the resulting interference produced during the potentiometric detection. It is found that the nicotinium cation binds the electronic rich aromatic cavity defined by the pyrrole rings of the receptor's cone conformation with an estimated binding constant higher than 10-4 M-1 in methylene chloride. On the other hand, the creatininium cation is preferentially included in the hydrophobic aromatic cavity of the ionophore by establishing hydrogen bond interactions with the pyrrole NHs groups. Potentiometric calibrations confirmed the detection of the nicotinium cation at neutral and acidic pH, respectively. Due to the lower pka of creatinine, a methodology to quantify creatinine in presence of nicotine by using an array of three sensors at two pH values is proposed. A partial least squares regression was performed and reported recoveries of 103% with a standard deviation of 20%. The improved determination of creatinine was therefore discussed. This approach represents a step forward in the development of effective approaches to improve the measurement of creatinine in decentralized settings.

Regional variability of glycemic control among adults with diabetes mellitus in Colombia.

Not available.

Integrated Management of Childhood Illnesses implementation-related factors at 18 Colombian cities.

BACKGROUND: Integrated Management of Childhood Illnesses (IMCI) is a strategy developed by the World Health Organization (WHO) and UNICEF in 1992. It was deployed as an integrated approach to improve children's health in the world. This strategy is divided into three components: organizational, clinical, and communitarian. If the Integrated Management of Childhood Illnesses implementation-related factors in low- and middle-income countries are known, the likelihood of decreasing infant morbidity and mortality rates could be increased. This work aimed to identify, from the clinical component of the strategy, the implementation-related factors to Integrated Management of Childhood Illnesses at 18 Colombian cities. METHODS: A quantitative cross-sectional study was performed with a secondary analysis of databases of a study conducted in Colombia by the Public Health group of Universidad de Los Andes in 2016. An Integrated Care Index was calculated as a dependent variable and descriptive bivariate and multivariate analyses to find the relationship between this index and the relevant variables from literature. RESULTS: Information was obtained from 165 medical appointments made by nurses, general practitioners, and pediatricians. Health access is given mainly in the urban area, in the first level care and outpatient context. Essential medicines availability, necessary supplies, second-level care, medical appointment periods longer than 30 min, and care to the child under 30 months are often related to higher rates of Integrated Care Index. CONCLUSION: Health care provided to children under five remains incomplete because it does not present the basic minimums for the adequate IMCI's implementation in the country. It is necessary to provide integrated care that provides medicine availability and essential supplies that reduce access barriers and improve the system's fragmentation.

Optical Supramolecular Sensing of Creatinine.

Calix[4]pyrrole phosphonate-cavitands were used as receptors for the design of supramolecular sensors for creatinine and its lipophilic derivative hexylcreatinine. The sensing principle is based on indicator displacement assays of an inherently fluorescent guest dye or a black-hole quencher from the receptor's cavity by means of competition with the creatinine analytes. The systems were thermodynamically and kinetically characterized regarding their 1:1 binding properties by means of nuclear magnetic resonance spectroscopy (1H and 31P NMR), isothermal titration calorimetry, and optical spectroscopies (UV/vis absorption and fluorescence). For the use of the black-hole indicator dye, the calix[4]pyrrole was modified with a dansyl chromophore as a signaling unit that engages in Förster resonance energy transfer with the indicator dye. The 1:1 binding constants of the indicator dyes are in the range of 107 M-1, while hexylcreatinine showed values around (2-4) × 105 M-1. The competitive displacement of the indicators by hexylcreatinine produced supramolecular fluorescence turn-on sensors that work at micromolar analyte concentrations that are compatible with those observed for healthy as well as sick patients. The limit of detection for one of the systems reached submicromolar ranges (110 nM).

Patient characteristics and pregnancy outcomes among Zika-infected pregnant women: Epidemiologic surveillance data from two cities in Colombia, 2015-2016.

OBJECTIVES: To describe the characteristics of pregnant women infected with Zika virus in two representative regions of Colombia, examine their pregnancy outcomes, and outline findings of the epidemiologic surveillance program established during the peak of the 2015-2016 epidemic. METHODS: A cohort study conducted in the municipalities of Cali and Villavicencio using data from the National Public Health Surveillance System (SIVIGILA) and clinical follow-up data from pregnant women. We describe sociodemographic characteristics, health insurance status, Zika virus, pregnancy-related characteristics, and pregnancy outcomes. RESULTS: A total of 1259 Zika-infected pregnant women were identified in Cali; of these, 2.3% (n=27) experienced pregnancy loss, 9.5% (n=113) had preterm birth, and 7.9% (n=91) had a low birthweight neonate. In Villavicencio, 3.0% (n=13) experienced pregnancy loss, 6.9% (n=30) had preterm birth, and 6.7% (n=28) had a low birthweight neonate. Compared with the general population, this population of Zika-infected pregnant women did not experience an increased frequency of preterm birth or low birthweight (relative risk of prematurity and low birthweight infant <1). CONCLUSIONS: Epidemiologic surveillance data showed that most neonates of Zika-infected pregnant women were born at term, and that the frequency of low birthweight neonates was low. Good quality data were obtained from the surveillance registries.

Spontaneous splenic rupture in a patient with chronic myeloid leukemia: A case report.

INTRODUCTION: Spontaneous splenic rupture is an atraumatic event that represents a rare and life-threatening acute complication in which the spleen is damaged producing internal hemorrhage in the abdominal cavity. Its association with hematologic malignancies, although a rare occurrence, has been previously described. Among this subset of patients, chronic myeloid leukemia is one of the main causes. PRESENTATION OF CASE: A 26-year-old male with history of chronic myeloid leukemia presented with acute intense abdominal right lower quadrant pain. Computed tomography showed a wedge in the lower third of the spleen (probably associated with infarction), active bleeding, and hemoperitoneum. Laparotomy and splenectomy were performed. DISCUSSION: The most common symptom of spontaneous splenic rupture is acute abdominal pain, sometimes radiating to the left shoulder. It can also be associated with nausea, emesis and signs of hypovolemia or shock. Splenomegaly may be absent. Diagnostic methods of choice are computed tomography and ultrasound. Management of splenic rupture is divided in surgical and conservative. The former is reserved for patients with extensive splenic injury that is accompanied by hemodynamic instability or other trauma that warrants surgical treatment. Patients who do not meet these criteria and respond to initial stabilization strategies can be offered clinical and laboratory monitoring. Stable patients with moderate to severe splenic injuries can be offered angioembolization. CONCLUSION: It is important to include splenic rupture as a differential diagnosis for acute abdominal pain, especially in patients with hematologic malignancy, since early recognition and treatment increases patient survival and improves prognosis.

EFFECT OF DIFFERENT SUBSTRATES AND AUXINS ON ROOTING OF Leucadendron sp. (PROTEACEAE) / EFECTO DE DIFERENTES SUSTRATOS Y AUXINAS EN EL ENRAIZAMIENTO DE Leucadendron sp. (PROTEACEAE)

ABSTRACT Colombian flower growers are faced with economic and social problems, so they are looking for alternatives, which include Proteas, ornamentals that require research that ensures an appropriate, local technical management. One of the Proteas most likely to be involved in this search is the genus Leucadendron. Therefore, this study aimed to establish the best basis for rooting its cuttings. The experimental design was a split plot design with a factorial arrangement. Four substrates were evaluated in combination with two auxins, naphthaleneacetic acid (NAA) and indolebutiric acid (IBA), three doses each, plus a commercial control. Each treatment was repeated three times and the experimental unit consisted of 30 stakes at the first locality and 25 at the second one. The most relevant results showed that vermiculite was the best substrate for rooting cuttings of Leucadendron at both localities. Also, it was identified that IBA is the growth regulator which improved the rooting percentage, the root volume, the stem decreased the percentage of losses.

RESUMEN Los cultivadores colombianos de flores tradicionales están confrontados con problemas, tanto económicos como sociales, por lo que están buscando alternativas, que incluyen a las Proteas, ornamentales que requieren investigación, que asegura un manejo técnico. Una de las Proteas con más posibilidad de estar involucrado en este desarrollo es el género Leucadendron. El diseño experimental empleado fue un diseño de parcelas, divididas con arreglo factorial. Así, que el objetivo de este estudio fue establecer la base para el enraizamiento de las estacas. En combinación con dos auxinas, ácido 1-naftalenacético (ANA) y ácido indolbutírico (AIB), tres dosis de cada una y el control comercial, se evaluaron cuatro sustratos. Cada tratamiento, se repitió tres veces y cada unidad experimental consistió en 30 estacas, para la primera localidad y de 25, para la segunda. Los resultados más relevantes mostraron que el mejor sustrato para el enraizamiento de estacas de Leucadendron fue la vermiculita, en ambas localidades. También, se identificó que AIB es el regulador de crecimiento que mejoró el porcentaje de enraizamiento, el volumen de raíces, la longitud del tallo disminuyó el porcentaje de pérdidas.

Diseño de bitácora centrado en el residente: conociendo y mejorando la experiencia de usuario / Design of resident-centered surgical logbook: knowing and improving the user´s experience

Introducción. Las bitácoras quirúrgicas son poco y mal utilizadas en nuestro medio. Bien elaboradas, se convierten en una herramienta útil, tanto para el residente como para la universidad, que permite evaluar el desempeño y tomar medidas cuando se determine necesario. Método. Es un estudio descriptivo de corte transversal en el que se evaluó un antes y un después del uso de la bitácora Logbook como herramienta tecnológica para el registro de procedimientos quirúrgicos. Se hizo una encuesta previa y otra posterior a un periodo de prueba de un mes (abril 2017), y se obtuvieron datos sobre el uso personal de su bitácora y las calificaciones de la herramienta presentada. Resultados. Diecisiete residentes (R1-R4) contestaron la encuesta y participaron en la prueba piloto. Quince de ellos (88,2 %) llevaban bitácora, la gran mayoría de ellos en un medio electrónico. Ocho (50 % de los que la usaban) calificaron como "regular" la experiencia con la bitácora actual y todos estarían dispuesto a adoptar una nueva opción. Solo tres (17,6 %) sabían que el uso de la bitácora es obligatoria en su universidad. Diez (71,4 %) calificaron la herramienta como "excelente" y, cuatro (28,6 %), como "buena". Todos la recomiendan, la continuarían usando y dicen que la herramienta les facilita cumplir con la tarea. Durante el periodo de prueba, 17 médicos usuarios registraron 276 entradas. Discusión. Una herramienta adecuada logra un mejor cumplimiento de los residentes de cirugía, y les facilita una gestión rápida y eficaz de su información, lo que genera conocimiento de su proceso de formación. Hacen falta un periodo mayor y un grupo de estudiantes más amplio, para validar estos datos

Introduction: Surgical logbooks are under- and misused. When used appropriately, they can become helpful tools for both residents and universities, letting the evaluation of progress and performance, so as to take action when indicated. Methods: Cross-sectional, descriptive, observational study evaluating Logbook for surgical case logging. We conducted a pre- and post-test survey (April 2017), and the data obtained reflected how they used their current caselogs and how they graded ours. Results: 17 residents (PGY1-PGY4) took the surveys and used the platform during the test period. Fifteen of them (88.2%) actually registered their cases, mostly on an e-platform. Eight (50%) had an "average" experience with their current tool, and 100% would consider a different option. Only three (17.6%) know it's mandatory to register cases at their University. Ten (71.4%) and four (28.6%) graded our tool as "excellent" or "good". 100% would recommend it to peers, would continue using it and believe it makes them more adherent to registering. During the test period, we had 17 users, and 276 entries were registered. Discussion: An appropriate tool to register procedures allows a better residence adherence. This can be done in an easy and diligent way, so that residents can gain knowledge from their own progress. Larger number of residents and longer periods of time are needed in order to validate our results

Ecuaciones alométricas de biomasa aérea para la estimación de los contenidos de carbono en manglares del Caribe Colombiano / Tree above-ground biomass allometries for carbon stocks estimation in the Caribbean mangroves in Colombia

ResumenLa distribución de carbono azul en los ecosistemas, entre los que se cuentan los manglares, es poco conocida en comparación con los grandes avances que existen para los ecosistemas forestales terrestres, a pesar de que su alta productividad y capacidad de almacenamiento de carbono es reconocida. Este estudio, tuvo por objetivo, analizar la biomasa aérea de las especies Rhizophora mangle y Avicennia germinans en el ecosistema de manglar localizado en el área marina protegida denominada Distrito de Manejo Integrado (DMI) Cispatá-Tinajones-La Balsa en el Caribe colombiano. Para ello, con la debida autorización oficial, se cosecharon 30 individuos de cada especie, con el fin de generar modelos alométricos que permitieran estimaciones de biomasa aérea con bajos niveles de incertidumbre. Los resultados indican que la biomasa aérea de los bosques de manglar del Caribe colombiano en el DMI, es de 129.69 ± 20.24 Mg/ha, es decir, que almacenan 64.85 ± 10.12 MgC/ ha. Teniendo en cuenta que el DMI presenta un área de 8 570.9 ha en bosques de manglar, se estima que el carbono total potencialmente almacenado por este ecosistema es de aproximadamente 555 795.93 MgC. Las ecuaciones generadas en este estudio se pueden considerar como una opción alternativa para la evaluación de las reservas de carbono en la biomasa aérea de los bosques de manglar en del Caribe colombiano, dado que otros modelos disponibles para la estimación de la biomasa aérea no discriminan a los bosques de manglar, a pesar de ser ecosistemas particulares. Los modelos pueden ser empleados como una opción para apoyar las estrategias de conservación de bosques y la reducción de emisiones. En general, el potencial de almacenamiento de carbono en los bosques de manglar del Caribe colombiano, es importante, y podría posesionar al país en la conservación de bosques y la reducción de emisiones a través de la conservación del carbono azul almacenado.

AbstractThe distribution of carbon in “Blue Carbon” ecosystems such as mangroves is little known, when compared with the highly known terrestrial forests, despite its particular and recognized high productivity and carbon storage capacity. The objective of this study was to analyze the above ground biomass (AGB) of the species Rhizophora mangle and Avicennia germinans from the Marine Protected Area of Distrito de Manejo Integrado (DMI), Cispatá-Tinajones-La Balsa, Caribbean Colombian coast. With official authorization, we harvested and studied 30 individuals of each species, and built allometric models in order to estimate AGB. Our AGB results indicated that the studied mangrove forests of the DMI Colombian Caribbean was of 129.69 ± 20.24 Mg/ha, equivalent to 64.85 ± 10.12 MgC/ha. The DMI has an area of 8 570.9 ha in mangrove forests, and we estimated that the total carbon potential stored was about 555 795.93 Mg C. The equations generated in this study can be considered as an alternative for the assessment of carbon stocks in AGB of mangrove forests in Colombia; as other available AGB allometric models do not discriminate mangrove forests, despite being particular ecosystems. They can be used for analysis at a more detailed scale and are considered useful to determine the carbon storage potential of mangrove forests, as a country alternative to support forest conservation and emission reduction strategies. In general, the potential of carbon storage from Colombian Caribbean mangrove forests is important and could promote the country leadership of the “blue carbon” stored. Rev. Biol. Trop. 64 (2): 913-926. Epub 2016 June 01.

Función del sistema NADPH oxidasa en la formación de trampas extracelulares de los neutrófilos (NETs) / Role of nadph oxidase system in the neutrophil extracelular Traps (NETs) formation

Las trampas extracelulares de los neutrófilos son estructuras fundamentalmente compuestas de cromatina y proteínas granulares, que una vez liberadas constituyen un mecanismo de defensa que tiene la capacidad de atrapar y destruir microorganismos patógenos. El proceso que libera estas estructuras es conocido como NETosis y en el caso que provoque muerte celular, esta es diferente a la apoptosis y a la necrosis. Si bien no se conocen todos los eventos moleculares involucrados en la formación de las NETs, se sabe que dependiendo del estímulo, las especies reactivas del oxígeno son esenciales para que ocurra la descondensación de la cromatina y se lleve a cabo el proceso de NETosis(AU)

Neutrophil extracellular traps (NETs) are structures mainly composed of chromatin and granule proteins that once released constitute a defense mechanism due to their ability to trap and destroy pathogen microorganisms. The process by which these structures are released is known as NETosis and in case this may lead to cell death is different to apoptosis and necrosis. Although all the molecular events involved in the formation of NETs are poorly understood, it is known that depending on the stimulus, reactive oxygen species (ROS) are essential to the chromatin decondensation and subsequent NETs formation(AU)

Biomasa y carbono total almacenado en robledales del sur de los Andes Colombianos: aportes para el enfoque REDD+ a escala de proyectos / Biomass and total carbon in oak forests of Southern Colombian Andes: contributions to the REDD+ project-wide approach

ResumenLas estimaciones de carbono en bosques tropicales, es muy importante para entender el papel de estos ecosistemas en el ciclo de este elemento. Este conocimiento permite apoyar y soportar las decisiones y la formulación de estrategias de mitigación y adaptación para reducir las emisiones de gases de efecto invernadero (GEI). Sin embargo, cuantificaciones detalladas de las existencias totales de carbono en los bosques montanos tropicales son limitadas, a pesar de su importancia científica y para el manejo de los ecosistemas (e.g. REDD+). Cuarenta y cuatro parcelas se establecieron en un paisaje heterogéneo compuesto por bosques maduros ubicados en el sur de los Andes colombianos. El objetivo fue identificar el papel de estos ecosistemas en el almacenamiento de carbono, evaluar la contribución de los reservorios analizados (biomasa aérea, biomasa subterránea y necromasa), y realizar contribuciones al enfoque de REDD+ en la escala de proyecto. En cada parcela se midieron todos los árboles, palmas y helechos con diámetro (D) ≥ 15 cm. En el caso de las palmas, se midió la altura de 40 % de los individuos, siguiendo el Protocolo Nacional de Colombia para estimar la biomasa y el carbono en los bosques naturales. Ecuaciones alométricas nacionales fueron utilizadas para estimar la biomasa aérea, y una ecuación general propuesta por el IPCC, fue utilizada para la estimación de la biomasa subterránea. La biomasa aérea de las palmas se estimó mediante un modelo local desarrollado para bosques montanos y premontanos. La necromasa se estimó para los árboles muertos en pie y los detritos gruesos. En este último caso, se midió la longitud y los diámetros de los extremos de las piezas. Las muestras para las estimaciones de densidad de madera, se recogieron en el campo y se analizaron en el laboratorio. El carbono promedio total se estimó en 545.9 ± 84.1 Mg/ ha (± SE). La biomasa aérea contribuyó con 72.5 %, la biomasa subterránea con 13.6 %, y la necromasa con 13.9 %. La principal conclusión de este estudio, es que los bosques montanos tropicales almacenan grandes cantidades de carbono, similares a las almacenadas por los bosques tropicales de tierras bajas. Además, se observó que la inclusión de otros compartimientos podría contribuir en más del 20 % de total del almacenamiento de carbono, lo que indica que las estimaciones que sólo incluyen la biomasa aérea, subestiman en gran medida las reservas de carbono en los ecosistemas forestales. Por tal razón, se sugiere incluir otros compartimientos en las estimaciones de carbono para iniciativas o proyectos REDD+.

AbstractCarbon estimations in tropical forests are very important to understand the role of these ecosystems in the carbon cycle, and to support decisions and the formulation of mitigation and adaptive strategies to reduce the greenhouse emission gases (GHG). Nevertheless, detailed ground-based quantifications of total carbon stocks in tropical montane forests are limited, despite their high value in science and ecosystem management (e.g. REDD+). The objective was to identify the role of these ecosystems as carbon stocks, to evaluate the contribution of the pools analyzed (aboveground biomass, belowground biomass and necromass), and to make contributions to the REDD+ approach from the project scale. For this study, we established 44 plots in a heterogeneous landscape composed by old-grown forests located in the Southern Colombian Andes. In each plot, all trees, palms and ferns with diameter (D) ≥ 15 cm were measured. In the case of palms, the height was measured for 40 % of the individuals, following the Colombia National Protocol to estimate biomass and carbon in natural forests. National allometric equations were used to estimate aboveground biomass, and a global equation proposed by IPCC was used for belowground biomass estimation; besides, palms' aboveground biomass was estimated using a local model. The necromass was estimated for dead standing trees and the gross debris. In the latter case, the length and diameters of the extremes in the pieces were measured. Samples for wood density estimations were collected in the field and analyzed in the laboratory. The mean total carbon stock was estimated as 545.9 ± 84.1 Mg/ha (± S.E.). The aboveground biomass contributed with 72.5 %, the belowground biomass with 13.6 %, and the necromass with 13.9 %. The main conclusion is that montane tropical forests store a huge amount of carbon, similar to low land tropical forests. In addition, the study found that the inclusion of other pools could contribute with more than 20 % to total carbon storage, indicating that estimates that only include the aboveground biomass, largely underestimate carbon stocks in tropical forest ecosystems. These results support the importance of including other carbon pools in REDD+ initiatives' estimations. Rev. Biol. Trop. 64 (1): 399-412. Epub 2016 March 01.

[Tree above-ground biomass allometries for carbon stocks estimation in the Caribbean mangroves in Colombia]. / Ecuaciones alométricas de biomasa aérea para la estimación de los contenidos de carbono en manglares del Caribe Colombiano.

The distribution of carbon in "Blue Carbon" ecosystems such as mangroves is little known, when compared with the highly known terrestrial forests, despite its particular and recognized high productivity and carbon storage capacity. The objective of this study was to analyze the above ground biomass (AGB) of the species Rhizophora mangle and Avicennia germinans from the Marine Protected Area of Distrito de Manejo Integrado (DMI), Cispatá-Tinajones-La Balsa, Caribbean Colombian coast. With official authorization, we harvested and studied 30 individuals of each species, and built allometric models in order to estimate AGB. Our AGB results indicated that the studied mangrove forests of the DMI Colombian Caribbean was of 129.69 ± 20.24 Mg/ha, equivalent to 64.85 ± 10.12 MgC/ha. The DMI has an area of 8 570.9 ha in mangrove forests, and we estimated that the total carbon potential stored was about 555 795.93 Mg C. The equations generated in this study can be considered as an alternative for the assessment of carbon stocks in AGB of mangrove forests in Colombia; as other available AGB allometric models do not discriminate mangrove forests, despite being particular ecosystems. They can be used for analysis at a more detailed scale and are considered useful to determine the carbon storage potential of mangrove forests, as a country alternative to support forest conservation and emission reduction strategies. In general, the potential of carbon storage from Colombian Caribbean mangrove forests is important and could promote the country leadership of the "blue carbon" stored.

Estructura y composición florística de los manglares de la bahía de Cispatá, Caribe colombiano

Los manglares son asociaciones de plantas que se adaptan fácilmente a las condiciones salinas y los niveles fluctuantes de inundación. Estos ecosistemas suministran gran cantidad de bienes y servicios tales como el almacenamiento de carbono. Diferencias estructurales, de composición de especies y de características microambientales entre tipos fisiográficos implican diferencias en el almacenamiento de carbono en sus suelos. La presente investigación tuvo como objetivo identificar la variación de las especies de mangle a través de los cambios en las variables físico-bióticas de bosques de manglar de la bahía Cispatá, Colombia. Se realizaron mediciones de variables estructurales del bosque (D, H, densidad de individuos) y medición de variables físico-bióticas (nivel de inundación, cobertura de A. aureum, salinidad del agua intersticial. pH del suelo, % N, % limo, % arena, % COs, raíces y densidad aparente en el suelo) en 12 parcelas establecidas aleatoriamente. Con un CCA identificaron tres manglares: cuenca, borde en buen estado de conservación y borde con intervención antropogénica. El primero dominado por A. germinans y los otros por R. mangle. El manglar de cuenca se diferencia de los de borde en términos estructurales y en variables físico-bióticas, presentó los valores más altos de COs, salinidad, densidad aparente y pH. Aunque los dos manglares de borde presentan características físico-bióticas similares, la alteración antropogénica cambia fuertemente la estructura de uno de ellos. Se ha concluido que la distribución de las especies de manglar de la bahía responde a la variación espacial de las características ambientales. Sin embargo, la intervención antropogénica es una variable determinante en la estructura de los manglares lo cual afecta las estimaciones del papel de diferentes tipos de manglar como sumideros de carbono.

Mangroves are plant associations that are easily adapted to saline conditions and fluctuating levels of flooding. This ecosystem provides a wide variety of goods and services as carbon storage. Structural differences, species composition and micro-environmental characteristics between physiographic types involve differences in carbon storage in their soils. This research aimed to identify the variation of mangrove species through changes in the physical-biotic variables of mangrove forest of Cispatá bay, Colombia. We measured structural variables of forest (D, H, density of individuals) as well as physico-biotic variables (flood level, A. aureum coverage, water interstitial salinity, soil pH, % N, % COs, roots and apparent density soil) in 12 plots established randomly. With a CCA it was identified three mangroves: basin, fringe in good condition and fringe with anthropogenic intervention. The first was dominated by A. germinans and the others by R. mangle. The basin mangrove differs from fringe in physical-biotic variables and structurally, it presented the highest values of COs, salinity, apparent density and pH. Although the two fringe mangrove exhibit similar physical-biotic variables, human disturbance may strongly change the structure of one of them. It was concluded that the distribution of mangrove species of bay responds to a spatial variation in environmental characteristics. However, anthropogenic intervention is a determining variable in the structure of mangroves which affects estimations of the role of different types of mangrove forests as carbon sinks.

Síntesis esteresselectiva de un nitro derivado e fenilvinilideno mediante la rreacción de heck usando fosfitos / Synthesis of a stereoselective nitro phenylenevinlene derivative by the heck reaaction using phosphites / Síntese eséreoseelectiva de um nitro derivado de fenilvfniideno mediante a reacção de heck usando fosofitos

En este trabajo se describen tanto la síntesis como la caracterización de E,E-1,4-dimetoxi-2,5-bis[2-(4-nitrofenil)etenil] benceno, mediante la reacción de acoplamiento cruzado de Heck usando trifenil-fosfito como ligante, lo cual -y teniendo en cuenta la literatura científica consultada- es el primer reporte de un doble acoplamiento de Heck empleando fosfitos como ligante en la formación del complejo catalítico con paladio. La caracterización del sistema fenilvinilideno obtenido muestra que el mecanismo es altamente estereoselectivo hacia la formación de enlaces trans, y su altísimo rendimiento (98%) indica que el sistema catalítico es bastante promisorio para realizar multiacoplamientos cruzados necesarios para obtener polímeros fenilvinilideno con altos pesos moleculares y altas eficiencias en las propiedades optoelectrónicas, necesarios para la tecnología de la electrónica de polímeros.

The synthesis and characterization of E,E-1,4-dimethoxy-2,5-bis[2-(4-nitrop-henyl)ethenyl]benzene by cross coupling Heck reaction using phosphites as ligands is described. This, to the best of our knowledge, is the first report involving a double Heck coupling using phosphites as ligand in the palladium catalyst formation. The characterization for the phenylenevinylene system obtained showed that the mechanism is highly stereoselective towards trans bond formation and its quantitative yield showed that this catalytic system is very promising for the multicoupling needed to obtain phenylenevinylene polymers with high molecular weights and high efficiency optoelectronic properties, in order to be used in polymer electronic technologies.

Neste trabalho descreve-se a síntese e caracterização de E,E-1,4-dimetoxi-2,5-bis [2-(4-nitrofenil)etenil]benceno, mediante a reação de acoplamentos cruzado ao Heck com trifenilfosfito como ligante. O qual, e tendo em conta a literatura científica pesquisada, é o primeiro reporte de um duplo acoplamento de Heck empregando fosfitos como ligante na formação do complexo catalítico com paladio. A caracterização do sistema fenilvinilideno obtido mostra que o mecanismo é altamente estereoselectivo para a formação de enlaces trans e que o sistema catalítico é bastante promisorio para fazer os acoplamentos cruzados necessários para obter polímeros de fenilvinilideno com alta massa molecular e altas eficiências nas propriedades optoelectronicas, necessários para a tecnologia da eletrônica de polímeros.