Comportamiento de vuelo del Aguilucho Común (Buteo polyosoma) durante el verano en Nevados de Chillán, Chile

We describe the flight behaviour of the Red-backed Hawk (Buteo polyosoma) during summer in Nevados de Chillán, Chile. Flight types most often used were gliding, wind-hovering and soaring (36.7%, 29.4% and 27.8% of the flying time, respectively). Spent time in gliding and wind-hovering peaked at mid-afternoon (17:00–19:00 h). Conversely, soaring was highest between mid-morning (10:00–11:00 h) and mid-day (13:00–14:00 h). Red-backed Hawk individuals appeared to use these flight types in an opportunistically manner using advantageous microclimatic and topographic conditions.Describimos los tipos de vuelo del Aguilucho Común (Buteo polyosoma) durante el verano en Nevados de Chillán, Chile. Los tipos de vuelo usados más a menudo fueron el vuelo planeado, el vuelo estacionario y el vuelo circular encumbrado (36.7%, 29.4% y 27.8% del tiempo de vuelo total, respectivamente). El tiempo invertido en el vuelo planeado y el vuelo estacionario fue máximo durante la media tarde (17:00–19:00 h). Por el contrario, la cantidad de tiempo invertido en el vuelo circular encumbrado fue mayor entre la media mañana (10:00–11:00 h) y el mediodía (13:00–14:00 h). Los aguiluchos parecieron usar estos tipos de vuelo de una manera oportunista, tomando provecho de las ventajas microclimáticas y las condiciones topográficas

Supersymmetry of gravitational ground states

A class of black objects which are solutions of pure gravity with negative cosmological constant are classified through the mapping between the Killing spinors of the ground state and those of the transverse section. It is shown that these geometries must have transverse sections of constant curvature for spacetime dimensions d below seven. For d > 6, the transverse sections can also be Euclidean Einstein manifolds. In even dimensions, spacetimes with transverse section of nonconstant curvature exist only in d = 8 and 10. This classification goes beyond standard supergravity and the eleven dimensional case is analyzed. It is shown that if the transverse section has negative scalar curvature, only extended objects can have a supersymmetric ground state. In that case, some solutions are explicitly found whose ground state resembles a wormhole.Comment: 16 pages, CECS style, minor correction

Aves asociadas al Aeropuerto Carriel Sur de Talcahuano, sur de Chile: evaluación de peligro aviario

Between the summer 2002 and 2005 was evaluated the richness and abundance of birds associated to the Carriel Sur Airport of Talcahuano and was estimated the collision risk representing each species for air navigation. Birds were counted in 10 count points distributed in different habitats around the landing runways. The collision risk was estimated by the Avian Hazard Index (AHI) which combines size, abundance and history of collisions of each species. During the study period 63 species were recorded, plus 10 aditional species were recorded after summer 2005. The most abundant species were the Grassland Yellow-Finch, Kelp Gull, Southern Lapwing Long-tailed Meadowlark (28%, 14%, 10%, 8% of all individual records). Excepting Kelp Gull, all remaining species exhibited seasonal cycles of abundance. The Kelp Gull showed multiyear outbreaks triggered. The species representing a higher collision risk for air navigation are the Kelp Gull (API = 36), Southern Lapwing (AHI = 24), South American Tern (AHI = 16), Black Vulture (AHI = 12), Neotropic Cormorant (AHI = 9) and Chimango Caracara (AHI = 8). However, the each species’ AHI varied temporally from very high to very low values according to changes in abundance. This study reflects the need for long-term assessments of changes in population size of bird species to better approximate the risk of bird-aircraft collisions.Entre el verano de 2002 y 2005 se evaluó la riqueza y abundancia de aves asociadas al Aeropuerto Carriel Sur de Talcahuano y se estimó el riesgo de colisión que representaría cada especie para la aeronavegación. Las aves fueron contabilizadas en 10 puntos de conteos distribuidos en distintos hábitats alrededor del las pistas de aterrizaje. El riesgo de colisión fue estimado mediante el índice de peligro aviario (IPA) el cual combina tamaño, abundancia e historial de colisiones de cada especie. Durante el periodo de estudio se registraron 63 especies, mas 10 especies que fueron registradas después del verano de 2005. Las especies más abundantes fueron el chirigüe, la gaviota dominicana, el queltehue y la loica (28%, 14%, 10%, 8% del total de registros individuales). Con excepción de la gaviota dominicana, todas las especies exhibieron ciclos estacionales de abundancia. La gaviota dominicana mostró irrupciones multianuales aparentemente por factores ambientales no bien determinados. Las especies que representarían un mayor riesgo de colisión para la aeronavegación son la gaviota dominicana (IPA = 36), el queltehue (IPA = 24), el gaviotín sudamericano (IPA = 16), el jote de cabeza negra (IPA = 12), el yeco (IPA = 9) y el tiuque (IPA = 8). Sin embargo, el IPA de cada especie varió temporalmente desde valores muy altos a valores muy bajos según los cambios de abundancia. Este estudio refleja la necesidad de evaluaciones de largo plazo de los cambios en el tamaño poblacional de especies de aves para una mejor aproximación del riesgo de colisiones aves-aeronaves

Endocardial Approach for Substrate Ablation in Brugada Syndrome

Radiofrequency ablation (RFA) in Brugada syndrome (BrS) has been performed by both endocardial and epicardial. The substrate in BrS is not completely understood. We investigate the functional endocardial substrate and its correlation with clinical, electrophysiological and ECG findings in order to guide an endocardial ablation. Two patients agreed to undergo an endocardial biopsy and the samples were examined with transmission electron microscopy (TEM) to investigate the correlation between functional and ultrastructural alterations. About 13 patients (38.7 ± 12.3 years old) with spontaneous type 1 ECG BrS pattern, inducible VF with programmed ventricular stimulation (PVS) and syncope without prodromes were enrolled. Before endocardial mapping, the patients underwent flecainide testing with the purpose of measuring the greatest ST-segment elevation for to be correlated with the size and location of substrate in the electro-anatomic map. Patients underwent endocardial bipolar and electro-anatomic mapping with the purpose of identify areas of abnormal electrograms (EGMs) as target for RFA and determine the location and size of the substrate. When the greatest ST-segment elevation was in the third intercostal space (ICS), the substrate was located upper in the longitudinal plane of the right ventricular outflow tract (RVOT) and a greatest ST-segment elevation in fourth ICS correspond with a location of substrate in lower region of longitudinal plane of RVOT. A QRS complex widening on its initial and final part, with prolonged transmural and regional depolarization time of RVOT corresponded to the substrate located in the anterior-lateral region of RVOT. A QRS complex widening rightwards and only prolonged transmural depolarization time corresponded with a substrate located in the anterior, anterior-septal or septal region of RVOT. RFA of endocardial substrate suppressed the inducibility and ECG BrS pattern during 34.7 ± 15.5 months. After RFA, flecainide testing confirmed elimination of the ECG BrS pattern. Endocardial biopsy showed a correlation between functional and ultrastructural alterations. Endocardial RFA can eliminate the BrS phenotype and inducibility during programmed ventricular stimulation (PVS)

Endocardial Approach for Substrate Ablation in Brugada Syndrome: Epicardial, Endocardial or Transmural Substrate?

Background: Radiofrequency ablation (RFA) in Brugada syndrome (BrS) has been performed both endocardially and epicardially. The substrate in BrS is thus unclear.Objectives: To investigate the functional endocardial substrate and its correlation with clinical, electrophysiological and ECG findings in order to guide an endocardial ablation.Methods: Thirteen patients (38.7±12.3 years old) with spontaneous type 1 ECG BrS pattern, inducible VF with programmed ventricular stimulation (PVS) and syncope without prodromes were enrolled. Before to endocardial mapping the patients underwent flecainide testing with the purpose of measuring the greatest ST-segment elevation for to be correlated with the size and location of substrate in the electro-anatomic map. Patients underwent endocardial bipolar and electro-anatomic mapping with the purpose of identify areas of abnormal electrograms (EGMs) as target for RFA and determine the location and size of the substrate.Results: When the greatest ST-segment elevation was in the 3rd intercostal space (ICS), the substrate was located upper in the longitudinal plane of the right ventricular outflow tract (RVOT) and a greatest ST-segment elevation in 4th ICS correspond with a location of substrate in lower region of longitudinal plane of RVOT. A QRS complex widening on its initial and final part, with prolonged transmural and regional depolarization time of RVOT corresponded to the substrate locateded in the anterior-lateral region of RVOT. A QRS complex widening rightwards and only prolonged transmural depolarization time corresponded with a substrate located in the anterior, anterior-septal or septal region of RVOT. RFA of endocardial substrate suppressed the inducibility and ECG BrS pattern during 34.7±15.5 months. After RFA, flecainide testing confirmed elimination of the ECG BrS pattern. Endocardial biopsy showed a correlation between functional and ultrastructural alterations in two patients.Keywords: Brugada syndrome; Radiofrequency catheter ablation; Electrocardiography; Mapping; Biopsy.Conclusion: Endocardial RFA can eliminate the BrS phenotype and inducibility during PVS.Fil: Tauber, Pablo E.. Centro Modelo del Corazón; Argentina. Gobierno de Tucumán. Ministerio de Salud. Hospital Centro de Salud "Zenón J. Santillán"; ArgentinaFil: Mansilla, Virginia. Centro Modelo del Corazón; ArgentinaFil: Brugada, Pedro. Free University of Brussels. Cardiovascular Division. Cardiovascular Institute; BélgicaFil: Sanchez, Sara Serafina del V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Honore, Stella Maris. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Elizari, Marcelo. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: Chain Molina, Sergio. Centro Modelo del Corazón; ArgentinaFil: Albano, Félix A.. Gobierno de Tucumán. Ministerio de Salud. Hospital Centro de Salud "Zenón J. Santillán"; ArgentinaFil: Corbalán, Ricardo R.. Centro Modelo del Corazón; ArgentinaFil: Figueroa Castellanos, Federico. Clínica Mayo; ArgentinaFil: Alzugaray, Damián. Abbott; Argentin

Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter

Climate change and human pressures are changing the global distribution and the ex‐ tent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (precon‐ ditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experi‐ mentally simulated, under standard laboratory conditions, rewetting of leaves, river‐ bed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative character‐ istics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dis‐ solved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contrib‐ uted most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental vari‐ ables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached sub‐ stances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying event

Latitude dictates plant diversity effects on instream decomposition

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113 degrees of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes

Spatial Evaluation and Modeling of Dengue Seroprevalence and Vector Density in Rio de Janeiro, Brazil

Dengue is a major public health problem in many tropical regions of the world, including Brazil, where Aedes aegypti is the main vector. We present a household study that combines data on dengue fever seroprevalence, recent dengue infection, and vector density, in three neighborhoods of Rio de Janeiro, Brazil, during its most devastating dengue epidemic to date. This integrated entomological–serological survey showed evidence of silent transmission even during a severe epidemic. Also, past exposure to dengue virus was highly associated with age and living in areas of high movement of individuals and social/commercial activity. No association was observed between household infestation index and risk of dengue infection in these areas. Our findings are discussed in the light of current theories regarding transmission thresholds and relative role of mosquitoes and humans as vectors of dengue viruses