35 research outputs found
Recommended from our members
Adaptation strategies to climate change in the Tropics: analysis of two multifactorial systems (high-altitude Andean ecosystems and Plasmodium falciparum malaria infections)
In this dissertation I focus my analyses of adaptation strategies to climate change on two areas of primary concern: (i) high-altitude ecosystems of the Tropical Andes, with particular interest in the so-called páramo ecosystems; and (ii) mosquito-borne diseases, focusing on Plasmodium falciparum malaria infections. My research on páramo ecosystems follows a six-tiered approach to understand the linkages between the ongoing changes in climatic conditions and the disruptions affecting the integrity of high-altitude environments. Activities conducted herein include the analyses of changes in atmospheric stability and lifting condensation levels; the diagnosis of changes in hydrological regimes; the assessment of the extent of life zones; the analyses of increases in the occurrence and rapid spread of high-altitude fires; the assessment of the integrity of páramo ecosystems; and the analyses of increases in climatic stress. Activities are conducted for three key, strategic, protected high-altitude Andean environments of the Tropical Andes and for the full length of the Andes Cordillera. My research findings provide elements for an improved understanding of the potential responses of Andean ecosystems to the large-scale rapidly changing climate and to a strongly-influential natural interannual variability. My research on P. falciparum malaria focuses on the analysis of the complexity behind the transmission dynamics of this multi-factorial disease. A deep understanding of such a complexity is possible through a holistic examination of the climatic, biological, socioeconomic, and demographic key-factors that are driving the fluctuations, changes and trends in malaria incidence. I propose a multi-model ensemble of malaria process-based models to offer useful information that could effectively guide decision-makers in risk assessment, malaria control investments and choice of interventions. I work on the integration of short-, medium- and long-term climate predictions into simulations of future changing scenarios, while helping to set up environment-informed systems at municipal level. My research thus provides a framework to: (a) compare the simulation outputs of several malaria process-based models with actual malaria morbidity profiles observed in several endemic- and epidemic-prone pilot sites in Colombia and Kenya; (b) explore the role that both climatic and non-climatic factors play in fluctuations and trends in malaria incidence, and analyze key confounders; (c) assess changing climate and future scenarios, and estimate the timing and possible magnitude of unexpected malaria outbreaks; (d) investigate current decision making processes, simulate the impact of indoor residual spraying campaigns, and provide quantitative goals for effective interventions; (e) conduct stability analysis; (f) pose and answer "what if" questions; and (g) stimulate an interactive learning environment to help decision makers learn
Climate and environmental monitoring for decision making
As human populations grow, so do the resource demands imposed on ecosystems and the impacts of our global footprint. Natural resources are not invulnerable, nor infinitely available. The environmental impacts of anthropogenic actions are becoming more apparent – air and water quality are increasingly compromised, pests and diseases are extending beyond their historical boundaries, and deforestation is exacerbating flooding downstream and loss of biodiversity. Society is increasingly becoming aware that ecosystem services are not only limited, but also that they are threatened by human activities. The need to better consider long-term ecosystem health and its role in enabling human habitation and economic activity is urgent. In this context IRI conducts research to understand the impact of climate and environmental changes on different sectors including agriculture, water management, human health, and natural disasters. Through exhaustive, rigorous evaluation, analysis and interpretation of remotely-sensed products and in-situ measurements, IRI ensures its partners have access to the most reliable and relevant information about the climate and environment in a format that best informs their decision making and planning. We focus on monitoring satellite-derived and in-situ estimates of precipitation, temperature, vegetation, water bodies, evapotranspiration, and land cover. Ultimately, the new products developed at IRI in partnership with other institutions at national (e.g. NOAA, NASA, USGS) and international (e.g. National Meteorology Agencies, UN FAO) levels are integrated into operational early-warning systems for health, natural disasters, agriculture, and food security. The new products which monitor in almost real-time climate and environmental conditions are made available through two online data bases at IRI called IRI Data Library and Map Room. In this paper we present the products developed at IRI and how they are integrated into Early Warning Systems (EWS). We also discuss IRI’s experience in linking EWS into decisions and policies using the fire early warning system as a concrete example
Testing a multi-malaria-model ensemble against 30 years of data in the Kenyan highlands
Background: Multi-model ensembles could overcome challenges resulting from uncertainties in models’ initial conditions, parameterization and structural imperfections. They could also quantify in a probabilistic way uncertainties in future climatic conditions and their impacts. Methods: A four-malaria-model ensemble was implemented to assess the impact of long-term changes in climatic conditions on Plasmodium falciparum malaria morbidity observed in Kericho, in the highlands of Western Kenya, over the period 1979–2009. Input data included quality controlled temperature and rainfall records gathered at a nearby weather station over the historical periods 1979–2009 and 1980–2009, respectively. Simulations included models’ sensitivities to changes in sets of parameters and analysis of non-linear changes in the mean duration of host’s infectivity to vectors due to increased resistance to anti-malarial drugs. Results: The ensemble explained from 32 to 38% of the variance of the observed P. falciparum malaria incidence. Obtained R2-values were above the results achieved with individual model simulation outputs. Up to 18.6% of the variance of malaria incidence could be attributed to the +0.19 to +0.25°C per decade significant long-term linear trend in near-surface air temperatures. On top of this 18.6%, at least 6% of the variance of malaria incidence could be related to the increased resistance to anti-malarial drugs. Ensemble simulations also suggest that climatic conditions have likely been less favourable to malaria transmission in Kericho in recent years. Conclusions: Long-term changes in climatic conditions and non-linear changes in the mean duration of host’s infectivity are synergistically driving the increasing incidence of P. falciparum malaria in the Kenyan highlands. User-friendly, online-downloadable, open source mathematical tools, such as the one presented here, could improve decision-making processes of local and regional health authorities
Recommended from our members
Matching Dendrochronological Dates with the Southern Hemisphere ¹⁴C Bomb Curve to Confirm Annual Tree Rings in Pseudolmedia rigida from Bolivia
This study used high-precision radiocarbon bomb-pulse dating of selected wood rings to provide an independent validation of the tree growth periodicity of Pseudolmedia rigida (Klotzsch & H. Karst.) Cuatrec. from the Moraceae family, collected in the Madidi National Park in Bolivia. ¹⁴C content was measured by accelerator mass spectrometry (AMS) in 10 samples from a single tree covering over 70 yr from 1939 to 2011. These preliminary calendar dates were determined by dendrochronological techniques and were also used to select the samples for ¹⁴C AMS. In order to validate these preliminary dates using the established Southern Hemisphere (SH) ¹⁴C atmospheric concentration data set, the targeted rings were selected to be formed during periods before and after the ¹⁴C bomb spike nuclear tests (i.e. 1950s–1960s). The excellent agreement of the dendrochronological dates and the ¹⁴C signatures in tree rings associated with the same dates provided by the bombpulse ¹⁴C atmospheric values for the SH (SHCal zone 1–2) confirms the annual periodicity of the observed growth layers, and thus the high potential of this species for tree-ring analysis. The lack of discrepancies between both data sets also suggests that there are no significant latitudinal differences between the ¹⁴C SHCal zone 1–2 curve and the ¹⁴C values obtained from the selected tree rings at this geographic location (14°33′S, 68°49′W) in South America. The annual resolution of P. rigida tree rings opens the possibility of broader applications of dendrochronological analysis for ecological and paleoclimatic studies in the Bolivian tropics, as well as the possibility of using wood samples from some tree species from this region to improve the quality of the bomb-pulse ¹⁴C SHCal curve at this latitude
Recommended from our members
Laboratory estimation of the effects of increasing temperatures on the duration of gonotrophic cycle of Anopheles albimanus (Diptera: Culicidae)
The increase of malaria transmission in the Pacific Coast of Colombia during the occurrence of El Niño warm event has been found not to be linked to increases in the density of the vector Anopheles albimanus, but to other temperature-sensitive variables such as longevity, duration of the gonotrophic cycle or the sporogonic period of Plasmodium. The present study estimated the effects of temperature on duration of the gonotrophic cycle and on maturation of the ovaries of An. albimanus. Blood fed adult mosquitoes were exposed to temperatures of 24, 27, and 30 degrees C, held individually in oviposition cages and assessed at 12 h intervals. At 24, 27, and 30 degrees C the mean development time of the oocytes was 91.2 h (95% C.I.: 86.5-96), 66.2 h (61.5-70.8), and 73.1 h (64-82.3), respectively. The mean duration of the gonotrophic cycle for these three temperatures was 88.4 h (81.88-94.9), 75 h (71.4-78.7), and 69.1 h (64.6-73.6) respectively. These findings indicate that both parameters in An. albimanus are reduced when temperatures rose from 24 to 30 degrees C, in a nonlinear manner. According to these results the increase in malaria transmission during El Niño in Colombia could be associated with a shortening of the gonotrophic cycle in malaria vectors, which could enhance the frequency of man-vector contact, affecting the incidence of the disease
Recommended from our members
Simulation of risk of tuberculosis infection in healthcare workers in hospitals of an intermediate incidence country
We simulated the frequency of tuberculosis infection in healthcare workers in order to classify the risk of TB transmission for nine hospitals in Medellín, Colombia. We used a risk assessment approach to estimate the average number of infections in three risk groups of a cohort of 1082 workers exposed to potentially infectious patients over 10- and 20-day periods. The risk level of the hospitals was classified according to TB prevalence: two of the hospitals were ranked as being of very high priority, six as high priority and one as low priority. Consistent results were obtained when the simulation was validated in two hospitals by studying 408 healthcare workers using interferon gamma release assays and tuberculin skin testing. The latent infection prevalence using laboratory tests was 41% [95% confidence interval (CI) 34·3–47·7] and 44% (95% CI 36·4–51·0) in those hospitals, and in the simulation, it was 40·7% (95% CI 32·3–49·0) and 36% (95% CI 27·9–44·0), respectively. Simulation of risk may be useful as a tool to classify local and regional hospitals according to their risk of nosocomial TB transmission, and to facilitate the design of hospital infection control plans
Recommended from our members
Implementation of Malaria Dynamic Models in Municipality Level Early Warning Systems in Colombia. Part I: Description of Study Sites
As part of the Integrated National Adaptation Pilot project and the Integrated Surveillance and Control System, the Colombian National Institute of Health is working on the design and implementation of a Malaria Early Warning System framework, supported by seasonal climate forecasting capabilities, weather and environmental monitoring, and malaria statistical and dynamic models. In this report, we provide an overview of the local ecoepidemiologic settings where four malaria process-based mathematical models are currently being implemented at a municipal level. The description includes general characteristics, malaria situation (predominant type of infection, malaria-positive cases data, malaria incidence, and seasonality), entomologic conditions (primary and secondary vectors, mosquito densities, and feeding frequencies), climatic conditions (climatology and long-term trends), key drivers of epidemic outbreaks, and non-climatic factors (populations at risk, control campaigns, and socioeconomic conditions). Selected pilot sites exhibit different ecoepidemiologic settings that must be taken into account in the development of the integrated surveillance and control system
Revista de Vertebrados de la Estación Biológica de Doñaña
Comportamiento reproductor del camaleón común (Chamaeleo chamaeleon L.) en el sur de EspañaDistribución de los reptiles en la provincia de Granada (SE. Península Ibérica)Datos sobre la reproducción y el crecimientode Psammodromus hispanicus Fitzinger, 1826 en un medio adehesado de la España CentralVariación en la colocación y orientación del nido del Alzacola (Cercotrichas galactotes) en dos especies de árbolesOrganización de la comunidad de aves reproductora en las landas montanas del País Vasco AtlánticoEcología de una población ibérica de lobos (Canis Lupus)Etude biométrique des Crosidures (Soricidae, Insectivora) de la región de Massa (Souss, Maroe).Variación geográfica del género Eliomys en la Península IbéricaTendencias gregarias del Ciervo (Cervus elaphus) en Doñana.Data on the autumn diet of the red deer (Cervus elaphus L. 1758) in the Montes de Toledo (Central Spain)Nota sobre la coexistencia de Hyla arborea (L. 1758E Hyla meridionalis (Boettger 1874) rn rl Valle del TiétarCalendario reproductivo y tamaño de las puesta en el galápago leproso, Mauremys leprosa (Shweigger, 1812), en Doñana, HuelvaPelícola (Felicola) inaqualis Piager, 1880 (MALLOPHAGA:TRICHODECTIDAE) parásito deE Herpestes ichneumon L (CARNIVORA: HERPESTIDAE)Abundancia y amplitud de los desplazamientos de Apodemus sylvaticus en cuatro biotopos de Doñana que difieren en cobertura vegetalPeer reviewe
Recommended from our members
Monitoring ecological change during rapid socio-economic and political transitions: Colombian ecosystems in the post-conflict era
After more than 50-years of armed conflict, Colombia is now transitioning to a more stable social and political climate due to a series of peace agreements between the government and different armed groups. Consequences of these socio-economic and political changes on ecosystems are largely uncertain, but there is growing concern about derived increases in environmental degradation. Here, we review the capacity of Colombia to monitor the state of its ecosystems and their rate of change over time. We found several important programs currently set in place by different institutions as well as by independent groups of scientists that address different aspects of environmental monitoring. However, most of the current initiatives could be improved in terms of data coverage, quality and access, and could be better articulated among each other. We propose a set of activities that would increase the capacity of Colombia to monitor its ecosystems, provide useful information to policy makers, and facilitate scientific research. These include: 1) the establishment of a national center for ecological synthesis that focuses on analyzing existing information; 2) the establishment of an ecological observatory system that collects new information, integrates remote sensing products, and produces near real-time products on key ecological variables; and 3) the creation of new platforms for dialog and action within existing scientific and policy groups
Implicaciones metodológicas e inconsistencias de la Tercera Comunicación Nacional sobre Cambio Climático de Colombia
Las Comunicaciones Nacionales sobre Cambio Climático (CNCC) son un mecanismo para que los países informen sus avances en mitigación y adaptación, y constituyen uno de los elementos de base para la política sobre cambio climático a escala nacional. Colombia ha emitido tres CNCC. La tercera plantea un escenario que considera las proyecciones de diversos modelos incluidos en la quinta fase del Proyecto de Comparación de Modelos Acoplados (Coupled Model Intercomparison Project, CMIP), el cual se estima como el promedio de las proyecciones correspondientes a las cuatro trayectorias de concentración representativa (Representative Concentration Pathways,RCP) presentadas en el quinto reporte de evaluación del Panel Intergubernamental sobre Cambio Climático. Cada una de estas RCP representa una trayectoria de concentración de gases de efecto invernadero (GEI) para un escenario particular de crecimiento poblacional, económico y tecnológico que conduce a una posible trayectoria de evolución del sistema climático. En este estudio se comparan las proyecciones presentadas en la Tercera CNCC con las obtenidas directamente de los modelos empleados. Nuestros resultados demuestran que al utilizarse un promedio de RCP se pierden escenarios alternos que podrían ser importantes a la hora de considerar posibles futuros diferentes y anulan la utilidad de plantear diversas trayectorias de emisiones de GEI. Más aun, una comparación entre la Segunda y la Tercera CNCC muestra proyecciones de precipitación opuestas para diferentes regiones del país, lo cual es de particular importancia, pues el escenario de cambio climático planteado en la Tercera CNCC sirve de referencia para la toma de decisiones en materia de cambio climático a nivel nacional