Artículos científicos

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Resistance and resilience in a directly regenerating rainforest: Nicaraguan trees of the Vochysiaceae after Hurricane Joan
(Elsevier, 1994-10) Boucher, Douglas H.; Vandermeer, John H.; Mallona, María Antonia; Zamora, Nelson; Perfecto, Ivette
Two trees of the family Vochysiaceae, Vochysiaferruginea and Qualea paraensis, were abundant in a Nicaraguan rainforest which was heavily damaged by Hurricane Joan in 1988, and both had recovered their previous densities by 1993. However, their regeneration followed quite different paths. Vochysia suffered complete mortality of adult trees in the hurricane, but rapid growth and high survivorship of its abundant seedlings and sprouts of saplings, restored its population density (though not yet its mean diameter at breast height) and indeed led to spatial expansion. Qualea, however, showed 100% survival of trees during the hurricane but substantial mortality in the following years. Although seedlings and sprouts of Qualea are quite rare, ingrowth is sufficient to maintain the population so far. However, vine growth on Qualea (unlike Vochysia) is substantial. These two species are thus contrasting elements of the 'direct regeneration' which has been observed in this rainforest. The Vochysia pattern of death and recovery can be described as 'resilience', while the Qualea pattern of survival can be called 'resistance'. The regenerating Vochysia population is mostly seedlings and saplings, while that of Qualea is mostly adult trees. Depending on the pattern of regeneration, different management strategies will be appropriate for maintaining tree species subject to natural disturbances such as hurricanes and/or artificial ones such as logging.
Altitudinal zonation of montane Quercus forests along two transects in Chirripó National Park, Costa Rica
(Springer, 1995-08) Kappelle, Maarten; Van Uffelen, Jan-Gerrit; Cleef, Antoine
Abiotic and vegetation data were collected along two altitudinal transects through mature montane Quercus forests on the Pacific and Atlantic slopes of Costa Rica's Chirripó Massif. Between 2000 and 3200 m asl twenty-four 0.05 ha forest plots were selected at altitudinal intervals of 100 m, and eight soil profiles were described at intervals of 200 m. A TWINSPAN classification aided in the determination of eight zonal forest communities on the basis of their floristic composition. They are grouped in two sets of four: (i) the palm-rich lauraceous-fagaceous Lower Montane Mollinedia-Quercus Forests (2000-2600 m asl) and (ii) the bamboo-rich myrsinaceous-fagaceous Upper Montane Schefflera-Quercus Forests (2500-3200 m asl), respectively. Vegetation changes seem correlated with two major climatic gradients: (i) a temperature gradient (altitude), and (ii) a moisture gradient (wet Atlantic vs. moist Pacific slope). Most soils are Andepts, and residual, colluvial or derived from volcanic material. Humus layers are thicker on the wetter Atlantic slope. A total of 431 vascular plant species consisted of 86 pteridophytes, 1 gymnosperm, 296 dicots and 48 monocots. Species richness, canopy height and stem diameter decrease with increasing altitude, while the canopy surface becomes more flattend. A comparison with other studies shows that Chirripó's montane Quercus forests fit within the environmental ranges known from altitudinal zonations elsewhere in the Tropics. © 1995 Kluwer Academic Publishers.
Anti-inflammatory and antinociceptive activities of Loasa speciosa in rats and mice
(Elsevier, 2003) Badilla Baltodano, Beatriz; Arias, A. Y.; Arias, M.; Mora, G. A.; Poveda Alvarez, Luis
In the range of doses of 250–500 mgykg (given i.p.) the aqueous extract of Loasa speciosa leaves showed an inhibitory effect on leukocyte migration, and a reduction on the pleural exudate, as well as dose-dependent anti-inflammatory and peripheral antinociceptive activities.
Inhibition of human pathogenic fungi by ethnobotanically selected plant extracts
(Deutschsprachige Mykologische Gesellschaft, 2003-02-14) Ficker, Christine E.; Arnason, J. T.; Sanchez Vindas, Pablo; Álvarez, L. P.; akpagana, koffi; Gbéassor, M.; De Souza, C.; Smith, M. L.
In this study, 36 extracts derived from 29 plant species selected using an ethnobotanical approach were tested for antifungal activity against a taxonomically diverse group of 13 human pathogenic fungi. We compared the inhibitory characteristics of these plant extracts with those of the commonly used antifungals, amphotericin B and ketoconazole, and the plant-derived antifungal, berberine. Several plant extracts, notably those from Zingiber officinale (ginger) and Juglans cinerea (butternut), had pronounced antifungal activity against a wide variety of fungi, including strains that were highly resistant to amphotericin B and ketoconazole. Further exploration of Z. officinale as an antifungal is warranted as this species is generally regarded as safe for human consumption.
Una nueva especie de Eugenia L. (Myrtaceae) de las selvas húmedas costarricenses
(Universidad de Costa Rica., 2004) Sánchez Vindas, Pablo
Se describe una nueva especie de Eugenia (Myrtaceae) de las veinte caribe de Costa Rica. Se distingue por las hojas con doble nervio marginal y los frutos acostillados y muy reticulado.
A regression analysis of Q'eqchi' Maya medicinal plants from southern Belize
(Universidad Nacional, Costa Rica, 2006) Sánchez Vindas, Pablo
Amiguet, V.T., Department of Biology, University of Ottawa, P.O. Box 450, Ottawa, Ont. K1N 6N5, Canada; Arnason, J.T., Department of Biology, University of Ottawa, P.O. Box 450, Ottawa, Ont. K1N 6N5, Canada; Maquin, P., Belize Indigenous Training Institute, Punta Gorda, Toledo District, Belize; Cal, V., Belize Indigenous Training Institute, Punta Gorda, Toledo District, Belize; Sänchez-Vindas, P., Herbario Juvenal, Universidad Nacional, Heredia, Costa Rica; Alvarez, L.P., Herbario Juvenal, Universidad Nacional, Heredia, Costa Rica
Cuatro compuestos nuevos del extracto no polar de la planta Amyris brenesii (Rutaceae) de Costa Rica
(Universidad de Costa Rica., 2008) Chavarría, Max; Castro, Victor; Poveda, Luis; Murillo, Renato
El estudio fitoquímico de las partes aéreas de Amyris brenesii (Rutaceae) recolectadas en Río Cuarto, Grecia, Alajuela (Costa Rica) mostró la presencia de cuatro nuevos compuestos: la 6-hidroxi-6-O-(3-hidroximetil-3-metilalil)- angelicina 1, el 6-(N-acetil-etanamin) -2,2-dimetil-2Hcromeno 2, el lignano 2,5-deshidrohinokinina 3 y la N-acetil-O-(geranil)-tiramina 4. Adicionalmente se aislaron los lignanos hinokinina 5, y justicidina E 6, las cumarinas escopoletina 7 y marmesina 8, el ácido 24-moretenoico 9 y el O-(3,3-dimetilalil)-halfordinol 10. Las separaciones se llevaron a cabo mediante la aplicación de técnicas cromatográficas y la elucidación de las estructuras se realizó con la ayuda de técnicas espectroscópicas de Resonancia Magnética Nuclear (RMN) de una y dos dimensiones.
Concentration of PM10 in the Metropolitan Area of Costa Rica, Central America: chemical composition and potential sources
(Universidad Nacional, Costa Rica, 2010) Herrera-Murillo, Jorge; Rojas Marín, José Félix; Rodríguez Román, Susana; Báez Pedrajo, Armando
Measurements of metals and inorganic ions were carried out on PM10. Sampling was made in five sites distributed in San José, Heredia and Belén cities. Samples were collected using Thermo Andersen PM10 high volume samplers with glass fiber and quartz filters. The ions SO4 2- , NO3- , Cl- , F- , PO43- , NH4 + , K+ , Na+ , Ca2+, Mg2+ were analyzed by ion chromatography and in the case of metals V, Cu, Cr, Pb, Ni, Mn, Fe, Al using an atomic absorption spectrometer with a graphite furnace attachment. The results indicated that SO42- was the most abundant ion, and with respect to metals, Al and Fe had the highest concentration. Spearman correlation, applied to all data, showed a high correlation between SO42- , NO3- and NH4+ indicating a common anthropogenic origin. From the metal species that were assessed only Pb and Cu presented enrichment factors higher than 10, indicating an anthropogenic contribution. Particles collected in the industrial zone of Belén showed the highest level of acidity and metal content.
Hypoglycemic and antihyperglycemic effect of Witheringia solanacea in normal and alloxan-induced hyperglycemic rats
(Elsevier, 2011) Herrera, Cristina; García Barrantes, Pedro M.; Binns, Franklin; Vargas, Marianela; Poveda, Luis Jorge; Badilla, Sandra
Witheringia solanacea is a small shrub that belongs to the Solanaceae family. The plant is used as an antidiabetic in Costa Rican herbal medicine. The aim of this study was to evaluate the hypoglycemic and antihyperglycemic activity of the aqueous extract of W. solanacea leaves in rodent models. About the materials and methods, a crude extract of W. solanacea leaves was prepared in boiling water and the aqueous filtrate was lyophilized. A single oral dose of 250, 500 and 1000 mg/kg of the extract was evaluated for hypoglycemic activity in a glucose tolerance test in normal rats and for antihyperglycemic activity in alloxan-induced (140 mg/kg) diabetic rats. The blood glucose level was determined at different times by the glucose oxidase method. It Result in a Dosage of 500 and 1000 mg/kg of the extract significantly decreased (p < 0.05) blood glucose levels in the glucose tolerance test in normal rats after 1 h, there was no significant difference observed at 250 mg/kg. Dose of 500 mg/kg of the extract significantly reduced (p < 0.05) blood glucose levels in alloxan induced hyperglycemic rats at 4 and 5 h. In Conclusion, in the present study, the hypoglycemic and antihyperglycemic potential of the W. solanacea was demonstrated in rats. These results give support to the traditional use of W. solanacea as antidiabetic herbal medicine.
Evolución de la contaminación del aire en la ciudad de San José, Costa Rica: 2004-2008
(Tecnología en Marcha, 2011) Herrera Murillo Jorge; Rodríguez Román Susana; Rojas Marín José Félix
Se evaluaron los promedios mensuales de dos contaminantes criterio, medidos en la ciudad de San José, durante el periodo 2004-2008: partículas PM10 y dióxido de nitrógeno. Al analizar las tendencias, se puede observar que en el caso de las partículas, la tasa de crecimiento anual se encuentra por debajo del 3%, o negativa en el caso de la Catedral Metropolitana, esto puede deberse al efecto positivo por la revisión técnica vehicular y la mejora en la calidad de los combustibles. Sin embargo, en el caso del dióxido de nitrógeno, se presentan tasas de crecimiento anual cercanas al 10% para zonas comerciales e industriales de la ciudad.
Determination of carbonyls and their sources in three sites of the metropolitan area of Costa Rica, Central America
(Springer Science+Business Media B.V, 2011-03-02) Herrera-Murillo, Jorge; Rojas Marín, José Félix; Rodríguez Román, Susana
Ambient levels of carbonyl compounds and their possible sources were studied at three places in the metropolitan area of Costa Rica, including a residential, an industrial, and a com mercial downtown area with high vehicular flow, during the periods of April–May and September– December 2009. Fifteen carbonyl compounds were identified in the ambient air, of which ace tone was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Concentra tions were highest in rainy season at all sites and lower in dry season. These decreases in concen tration are explained by the influences of both photochemical reactions and local meteorological conditions. The strong correlation between C1– C2 and C3 indicated a common origin for these carbonyls. The C1/C2 ratios varied between 0.49 to 1.05, values which can be considered typical of an urban area
Parasites of cetaceans stranded on the Pacific coast of Costa Rica
(Revista de parasitología veterinaria, 2011-05-12) Oliveira, J.B.; Morales, J.A.; González, R.C.; Hernández, J; Hernández, G
Information regarding parasitic fauna of cetaceans from Costa Rica is provided for the first time. A total of 25 stranded dolphins and whales were examined between 2001 and 2009, including striped dolphin (Stenella coeruleoalba) (n = 19), pantropical spotted dolphin (S. attenuata) (n = 2), spinner dolphin (S. longirostris) (n = 1), bottlenose dolphin (Tursiops truncatus) (n = 1), dwarf sperm whale (Kogia sima) (n = 1) and Cuvier’s beaked whale (Ziphius cavirostris) (n = 1). Pathological findings associated with the parasites are also presented. In the most representative dolphin species, S. coeruleoalba, the prevalence of parasites was 89.5%; moreover, all examined specimens of S. attenuata, S. longirostris, T. truncatus and Z. cavirostris presented parasites. No parasites were recovered from K. sima. Fourteen helminth taxa were identified, including six species of cestodes (Strobilocephalus triangularis, Tetrabothrius forsteri, Trigonocotyle sp., Phyllobothrium delphini, Monorygma grimaldi, Tetraphyllidea gen. sp. plerocercoid), four digeneans (Nasitrema globicephalae, Brachycladium palliatum, B. pacificum and Oschmarinella albamarina) and four nematodes (Anisakis spp., Halocercus lagenorhynchi, Halocercus sp. and Crassicauda anthonyi). A commensal crustacean, Xenobalanus globicipitis, was also identified. All identified parasites representing new geographic records for the Pacific coast of Central America and new host records are presented. Parasitological information is valuable for conservation of cetaceans in Pacific coast of Costa Rica.
New Bruce-ladder multiplex PCR assay for the biovar typing of Brucella suis and the discrimination of Brucella suis and Brucella canis
(Revista de Microbiología Veterinaria, 2011-06-28) López-Goñi, Ignacio; García-Yoldi, David
Rapid and specific identification of Brucella suis at the biovar level is necessary because some of the biovars that infect animals are pathogenic for humans. None of the molecular typing methods described so far are able to discriminate B. suis biovars in a single test and differentiation of B. suis from Brucella canis by molecular approaches can be difficult. This article describes a new multiplex PCR assay, Suis-ladder, for fast and accurate identification of B. suis at the biovar level and the differentiation of B. suis, B. canis and Brucella microti. An advancement of the original Bruce-ladder PCR protocol which allows the correct discrimination of all known Brucella species is also described.
Carbon accumulation in the biomass and soil of different aged secondary forests in the humid tropics of Costa Rica
(Elsevier, 2011-10-15) Fonseca, William; Rey Benayas, José María; Alice-Guier, Federico E.
Efforts are needed in order to increase confidence for carbon accounts in the land use sector, especially in tropical forest ecosystems that often need to turn to default values given the lack of precise and reliable site specific data to quantify their carbon sequestration and storage capacity. The aim of this study was then to estimate biomass and carbon accumulation in young secondary forests, from 4 and up to 20 years of age, as well as its distribution among the different pools (tree including roots, herbaceous understory, dead wood, litter and soil), in humid tropical forests of Costa Rica. Carbon fraction for the different pools and tree components (stem, branches, leaves and roots) was estimated and varies between 37.3% (±3.3) and 50.3% (±2.9). Average carbon content in the soil was 4.1% (±2.1). Average forest plant biomass was 82.2 (±47.9) Mg ha 1 and the mean annual increment for carbon in the biomass was 4.2 Mg ha 1 yr 1 . Approximately 65.2% of total biomass was found in the aboveground tree components, while 14.2% was found in structural roots and the rest in the herbaceous vegetation and necromass. Carbon in the soil increased by 1.1 Mg ha 1 yr 1 . Total stored carbon in the forest was 180.4 Mg ha 1 at the age of 20 years. In these forests, most of the carbon (51–83%) was stored in the soil. Models selected to estimate biomass and carbon in trees as predicted by basal area had R2 adjustments above 95%. Results from this study were then compared with those obtained for a variety of secondary and primary forests in different Latin-American tropical ecosystems and in tree plantations in the same study area
Carbon accumulation in aboveground and belowground biomass and soil of different age native forest plantations in the humid tropical lowlands of Costa Rica
(Universidad Nacional, Costa Rica, 2012) Fonseca, William; Alice, Federico E.; Rey Benayas, José
Generic or default values to account for biomass and carbon accumulation in tropical forest ecosystems are generally recognized as a major source of errors, making site and species specific data the best way to achieve precise and reliable estimates. The objective of our study was to determine carbon in various components (leaves, branches, stems, structural roots and soil) of single-species plantations of Vochysia guatemalensis and Hieronyma alchorneoides from 0 to 16 years of age. Carbon fraction in the biomass, mean (±standard deviation), for the different pools varied between 38.5 and 49.7% (±3 and 3.8). Accumulated carbon in the biomass increased with the plantation age, with mean annual increments of 7.1 and 5.3 Mg ha-1 year-1 for forest plantations of V. guatemalensis and H. alchorneoides, respectively. At all ages, 66.3% (±10.6) of total biomass was found within the aboveground tree components, while 18.6% (±20.9) was found in structural roots. The soil (0–30 cm) contained 62.2 (±13) and 71.5% (±17.1) of the total carbon (biomass plus soil) under V. guatemalensis and H. alchorneoides, respectively. Mean annual increment for carbon in the soil was 1.7 and 1.3 Mg ha-1 year-1 in V. guatemalensis and H. alchorneoides. Allometric equations were constructed to estimate total biomass and carbon in the biomass which had an R2 aj (adjusted R square) greater than 94.5%. Finally, we compare our results to those that could have resulted from the use of default values, showing how site and species specific data contribute to the overall goal of improving carbon estimates and providing a more reliable account of the mitigation potential of forestry activities on climate change.
La red internacional de inventarios forestales (BIOTREE-NET) en Mesoamérica: avances, retos y perspectivas futuras
(Asociación Española de Ecología Terrestre, 2012) Cayuela, Luis; Gálvez Bravo, L.; de Albuquerque, F.S.; Golicher, D. J.; González Espinosa, M.; Ramírez Marcial, N.; Rey Benayas, José María; Zahawi, R.A.; Meave, J.A.; Benito, B.M.; Garibaldi, C.; Chan, I.; Pérez Pérez, R.; Field, R.; Balvanera, P.; Castillo, M.A.; Figueroa Rangel, B.L.; Griffith, D.M.; Islebe, G.A.; Kelly, D.L.; Olvera Vargas, M.M; Schnitzer, S.A.; Velazquez, E.; Williams Linera, G.; Brewer, S.W.; Camacho Cruz, A.; Coronado, I.; de Jong, B.; del Castillo, R.R.; Granzow de la Cerda, I.; Fernández, J.; Fonseca González, William; Galindo Jaimes, L.; Gillespie, T.W.; González Rivas, B.; Gordon, J.E; Hurtado, J.; Linares, J.; Letcher, S.G.; Mangan, S.A; Méndez, V.E.; Meza, V.; Ochoa-Gaona, S.; Peterson, C.J.; Ruiz Gutierrez, V.; Snarr, K.A.; Tun Dzul, F.; Valdez Hernández, M.; Viergever, K.M.; White, D.A.; Williams, J.N.; Bonet, F.J.; Zamora, R.
Los esfuerzos de conservación en la región neotropical están limitados por la falta de información disponible sobre las especies, ya que muchas no han sido descritas o se tiene poca información sobre ellas. La Red Internacional de Inventarios Forestales (BIOTREE-NET) concentra y facilita el acceso a la información y el intercambio entre investigadores, gestores y conservacionistas, organizando y estandarizando los datos de especies de árboles procedentes de inventarios forestales en la región mesoamericana en una única base de datos que incluya información espacial. Este artículo explica el ámbito y objetivos de la red, describe la estructura de la base de datos e identifica los principales avances realizados, así como los retos y perspectivas futuras. La base de datos contiene más de 50 000 registros de árboles de unas 5000 especies, distribuidas en más de 2000 parcelas muestreadas desde el suroeste de México hasta Panamá. La información es heterogénea, tanto en su naturaleza y forma como en la cobertura geográfica de los inventarios. La base de datos tiene una estructura relacional, con 12 tablas interconectadas, incluyendo información sobre las parcelas, los nombres de las especies, el diámetro a la altura del pecho de los árboles medidos y sus atributos funcionales. Se ha desarrollado un sistema para la corrección de errores tipográficos y la estandarización taxonómica y nomenclatural utilizando como referencia The Plant List (http://theplantlist.org/). También se han generado modelos de distribución potencial para cerca de 1700 especies utilizando distintos métodos y en el futuro se prevé habilitar también el acceso público a los modelos de distribución de especies a través del portal web (http://portal.biotreenet.com). Aunque BIOTREE-NET ha contribuido al desarrollo de mejores modelos de distribución, su mayor potencial radica, en nuestra opinión, en el estudio a nivel de comunidades. Finalmente, se reconoce la necesidad de expandir la red a través de la participación de más investigadores interesados en colaborar con datos para ampliar el conocimiento sobre la biodiversidad forestal en la región neotropical.
Relations Between Bulk Precipitation, PM10 Composition and Meteorological Conditions in the Metropolitan Area of Costa Rica
(The Open Atmospheric Science Journal, 2012-02-06) Herrera-Murillo, Jorge; Rodríguez, Susana; Rojas, José Félix; Báez, Armando
Concentrations of inorganic ions (Cl -, H +, SO 4 2-, NO 3 -, NH 4 +, Na +, K +, Ca 2+, Mg 2+) and metals (V, Ni, Cu, Pb, Cr Mn, Al, Fe) in bulk precipitation and PM 10 samples collected in the metropolitan area of Costa Rica were analyzed. Good correlations between acidity in bulk precipitation with the concentrations of aerosols in the air were observed. The scavenging of the pollutants from the air directly affects the pH and composition of the bulk precipitation. The major ions in bulk precipitation in the metropolitan area of Costa Rica were SO 4 2-, NH 4 +, Ca 2 +, Na + ion percentages with 41.4, 12.0, 10.9 and 9.1 respectively. Al, Fe and Mn were the most abundant trace metals. The alkaline cations, NH 4 + and Ca 2+, acted as acid neutralizers and buffered the acidity of bulk precipitation. Meteorological conditions presented during the events determine the composition of bulk precipitation samples.
Impacto económico de los pagos por carbono y servicios ambientales en las inversiones forestales en la región Caribe de Costa Rica
(Asociación Española de Ecología Terrestre, 2012-03-16) Fonseca González, William; Navarro, G.; Alice, Federico E.; Rey Benayas, José María
El objetivo de este estudio fue estimar el balance de la inversión asociada a la restauración forestal por medio del establecimiento de plantaciones (Vochysia guatemalensis e Hieronyma alchorneoides) y de la regeneración natural (bosque secundario sin y con manejo intensivo). Se consideraron diferentes escenarios económicos donde se evaluaron ingresos por: venta de la madera, pago de los servicios ambientales (PSA) provenientes del Fondo de Financiamiento Forestal (FONAFIFO) del gobierno costarricense y por venta de certificados de reducción de emisiones de carbono (CER). Se comparó la actividad forestal contra usos alternativos de la tierra como ganadería, banano y piña. El análisis de las inversiones se evalúo tomando como criterio el valor esperado de la tierra (VET) con tasas anuales de descuento aceptables (TMA) del 3%, 6% y 9,0% las cuales reflejan las preferencias y condiciones de diferentes inversionistas. Para las plantaciones forestales y bosque secundario sin manejo y con manejo intensivo se estimó una inversión total promedio de US$5200, US$1730 y US$1373 ha-1, respectivamente. Los ingresos estimados por la venta de la madera superaron los US$21142 ha-1 entre ambas especies, US$1250 y US$13408 ha-1 para el bosque secundario con manejo mínimo y con manejo intensivo, respectivamente. Los ingresos por CER y por PSA representan cantidades marginales en comparación con los ingresos por madera. El cultivo de piña y el de banano como usos alternativos de la tierra son los más rentables, seguido por las plantaciones forestales y por último la ganadería y los bosques secundarios con y sin manejo, que no solo son los menos rentables, sino que tienen sus valores calculados por debajo del precio de la tierra. La restauración forestal no resulta una actividad atractiva económicamente para el propietario de la tierra, basado solamente en ingresos provenientes de pagos de servicios ambientales o venta de carbono a los precios actuales. Los precios más altos de la madera y una tasa de descuento baja (que representan condiciones macroeconómicas favorables), son los factores determinantes para hacer eficientes y sostenibles las inversiones forestales tanto en bosque secundario como en plantaciones forestales en la región Caribe de Costa Rica.
Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010
(Copernicus Publications, 2012-09) Nölscher, Anke C.; Williams, Jonathan; Sinha, Vinayak; Custer, Thomas G.; Wei, Song; Axinte, R.; Bozem, Heiko; Fischer, H.; Pouvesle, N.; Phillips, Gavin; Crowley, J. N.; Rantala, P.; Rinne, Janne; Rantala, P.; Rinne, Janne; Kulmala, Markku; González, D.; Valverde-Canossa, jessica; Vogel, Alexander; Hoffmann, Thorsten; Ouwersloot, H.G.; Vilà-Guerau de Arellano, j.; Lelieveld, j.
La reactividad ambiental total de OH se midió en la estación forestal boreal finlandesa SMEAR II en Hyytiälä (Latitud 61°51' N; Longitud 24°17' E) en julio y agosto de 2010 utilizando el Método de Reactividad Comparativa (MRC). El MRC (método de reactividad total de OH) es una determinación directa in situ de la tasa total de pérdida de radicales hidroxilo (OH) causada por todas las especies reactivas en el aire. Durante la campaña de campo intensiva HUMPPA-COPEC 2010 ( H yytiälä United M easurements of P hotochemistry and P articles in Air – C omprehensive Organic P recursor Emission and C oncentration study) la reactividad total de OH se monitoreó tanto dentro (18 m) como directamente sobre el dosel forestal (24 m) por primera vez. Aquí se ha analizado la comparación entre estas dos mediciones de reactividad total de OH, los valores absolutos y la variación temporal. Las condiciones estables de la capa límite durante la noche y la mezcla turbulenta durante el día indujeron una variabilidad a corto plazo baja y alta, respectivamente. El impacto de las emisiones biogénicas y los productos fotoquímicos asociados en la reactividad total del OH se midió en condiciones normales y de estrés (es decir, con altas temperaturas prolongadas). La advección de las emisiones de la quema de biomasa al sitio provocó un cambio marcado en el perfil vertical de la reactividad total del OH. Al comparar la contribución de la reactividad del OH de los compuestos medidos individualmente y la reactividad total del OH medida directamente, se puede deducir el tamaño de cualquier sumidero no contabilizado o "faltante" para diversas influencias atmosféricas. Para condiciones boreales "normales" se determinó una reactividad del OH faltante del 58%, mientras que para condiciones boreales "estresadas" se determinó una reactividad del OH faltante del 89%. Se proponen diversas fuentes de especies reactivas al OH no cuantificadas como posible explicación de la alta reactividad del OH faltante.
Indigenous Ex Situ Conservation of Q'eqchi' Maya Medicinal Plant Resources at the Itzamma Garden-Indian Creek, Belize, Central America
(Springer Science, 2012-12-27) Audet, Patrick; Arnason, John; Audet, Patrick; Walshe-Roussel, Brendan; Cal, Victor; Caal, Francisco; Otárola Rojas, Marco Antonio; Sanchez Vindas, Pablo; Poveda Alvarez, Luis; Pesek, Todd; Arnason, John
The Itzamma Garden and Medicinal Plant Project is a collaborative effort focused on identifying traditionally important plants used by the Q'eqchi' Maya of southern Belize. The Garden represents a cornerstone of the project where these plant resources (~130 in total, of which 102 have been identified to the species level) are cultivated ex situ as a means of providing primary healthcare by traditional healers. Here, we present a comprehensive agro-ecological survey of the Garden describing the layout and cultivation scenarios, development challenges encountered, and associated implementation strategies for improving site practices. A general recommendation for the adaptation of this strategy to other localities is the thorough depiction of ecological features based on interactions with local practitioners, for example, leading to the effective cultivation of plants, the enhancement of soil, and the surveillance of crop nutritional status and medicinal potency. We consider that the 'ethnobotanical garden approach' could provide a collaborative 'working model' for rural development, especially indigenous communities interfacing with their local agro-ecosystems.

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