Oceanography using remote sensors Status report, 1 Sep. 1967 - 1 Jan. 1968

Aircraft and spacecraft remote sensing of oceanographic features and interpretation of photography taken during Apollo 501 missio

The persistence of simple host-parasitoid systems with prolonged diapause

Many univoltine insect populations can spread adult emergence in time through a phenomena known as prolonged diapause. With the exception of a few works, the dynamic consequences of prolonged diapause in coupled host parasitoid populations remains an open question. We modified the classical Nicholson-Bailey model to consider synchronic prolonged diapause in a model lacking other stabilising features. Our results add evidence to past work in that they show that this phenomena may be of little importance to the stability of hostparasitoid systems. However, the model predicts long-term persistence through abrupt oscillations. This feature may in itself help explain the population behaviour of many insect populations exhibiting outbreak dynamics and sets the emphasis on the importance of looking into transient dynamics

Valor medio de la distribución de espín a través de relaciones isoméricas

Fil:Capurro, Oscar A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Diversity of multi-drug resistant Acinetobacter baumannii population in a major hospital in Kuwait

Acinetobacter baumannii is one of the most important opportunistic pathogens that causes serious health care associated complications in critically ill patients. In the current study we report on the diversity of the clinical multi-drug resistant (MDR) A. baumannii in Kuwait by molecular characterization. One hundred A. baumannii were isolated from one of the largest governmental hospitals in Kuwait. Following the identification of the isolates by molecular methods, the amplified blaOXA-51-like gene product of one isolate (KO-12) recovered from blood showed the insertion of the ISAba19 at position 379 in blaOXA-78. Of the 33 MDR isolates, 28 (85%) contained blaOXA-23, 2 (6%) blaOXA-24 and 6 (18%) blaPER-1 gene. We did not detect blaOXA-58, blaV IM, blaIMP, blaGES, blaV EB, and blaNDM genes in any of the tested isolates. In three blaPER-1 positive isolates the genetic environment of blaPER-1 consisted of two copies of ISPa12 (tnpiA1) surrounding the blaPER-1 gene on a highly stable plasmid of ca. 140-kb. Multilocus-sequence typing (MLST) analysis of the 33 A. baumannii isolates identified 20 different STs, of which six (ST-607, ST-608, ST-609, ST-610, ST-611, and ST-612) were novel. Emerging STs such as ST15 (identified for the first time in the Middle East), ST78 and ST25 were also detected. The predominant clonal complex was CC2. Pulsed-field gel electrophoresis and MLST defined the MDR isolates as multi-clonal with diverse lineages. Our results lead us to believe that A. baumannii is diverse in clonal origins and/or is undergoing clonal expansion continuously while multiple lineages of MDR A. baumannii circulate in hospital ward simultaneously

Especificidad y denso-dependencia inversa en parasitoides con oviposición fuera del hospedador : el caso de Mallophora ruficauda (Diptera: Asilidae) en la Pampa Argentina

Estudiamos los fenómenos de especificidad denso-dependencia, asociados al parasitismo, en un sistema hóspedador parasitoide cuyas hembras parasitoides carecen del habitual comportamiento de búsqueda del hospedador. Para ello tomamos el sistema compuesto por los gusanos blancos del suelo (Coleoptera: carabaeidae) y el moscardón cazador de abejas Mallophora ruficauda Wiedemann 1828 (Diptera: Asilidae). El estudio se realizó en las inmediaciones de 8 apiarios ubicados en las provincias de Buenos Aires y Entre Ríos, y durante el mes de Junio de 1997. El moscardón posee un índice de referencia en la elección de su hospedador de 0.69, indicando que es ligeramente selectivo hacia Cyclocephala signaticollis (90% de parasitismo). Fenómenos de denso-dependencia inversa se manifestaron a escala pequeña, al analizar mediante regresión lineal y evaluaciones “Jackknife “, las variables abundancia de gusanos en el suelo (In) y porcentaje de parasitismo (In), indicando que el parasitoide satura sus posibilidades de parasitar más hospedadores a medida que aumenta la abundancia de los mismos en el suelo. Este fenómeno estaría vinculado a la forma que posee el parasitoide de colocar sus huevos, ya que no ovipone directamente sobre el hospedador ‘sino sobre vegetación elevada, valiéndose del viento para la dispersión de sus larvas. El encuentro hospedador parasitoide estaría ligado a la coincidencia Osimultánea en el espacio de la distribución de los hospedadores y de las larvas parasitoides en el suelo.We study the specificity and density dependence phenomena associated to the parasitism, in a host parasitoid system whose females do not have common host search behavior. We studied the system composed by the soil white worms (Coleoptera: Scarabaeidae) and the bee hunter robber fly Mallophora ruficauda Wiedemann 1828 (Diptera: Asilidae). The study was conducted in the nearness of eight apiaries located in the provinces of Buenos Aires and Entre Ríos, during the month of June of 1997. The robber fly possesses a 0.69 preference index in the election of his host, indicating that it is lightly selective toward Cyclocephala signaticollis (90% of parasitism). Phenomena of inverse density dependence were observed when analyzing at small scale the variable abundance of worms in the soil (ln) and percentage of parasitism (In) using lineal regression and “Jackknife” estimations. This result indicates that the parasitoid saturates their possibilities to parasite more hosts as the abundance of the latter increases in the soil. This phenomenon could be linked to the particular egg laying characteristics of the parasitoid. Eggs are not lay directly on the host, but on high vegetation taking advantage of the wind for the dispersion of its larvae. The host-parasitoid encounter could be bound to the simultaneous coincidence in the space of the distribution of the hosts and the larvae parasitoids in the soil

Suppression of a Field Population of Aedes aegypti in Brazil by Sustained Release of Transgenic Male Mosquitoes

The increasing burden of dengue, and the relative failure of traditional vector control programs highlight the need to develop new control methods. SIT using self-limiting genetic technology is one such promising method. A self-limiting strain of Aedes aegypti, OX513A, has already reached the stage of field evaluation. Sustained releases of OX513A Ae. aegypti males led to 80% suppression of a target wild Ae. aegypti population in the Cayman Islands in 2010. Here we describe sustained series of field releases of OX513A Ae. aegypti males in a suburb of Juazeiro, Bahia, Brazil. This study spanned over a year and reduced the local Ae. aegypti population by 95% (95% CI: 92.2%-97.5%) based on adult trap data and 81% (95% CI: 74.9-85.2%) based on ovitrap indices compared to the adjacent no-release control area. The mating competitiveness of the released males (0.031; 95% CI: 0.025-0.036) was similar to that estimated in the Cayman trials (0.059; 95% CI: 0.011-0.210), indicating that environmental and target-strain differences had little impact on the mating success of the OX513A males. We conclude that sustained release of OX513A males may be an effective and widely useful method for suppression of the key dengue vector Ae. aegypti. The observed level of suppression would likely be sufficient to prevent dengue epidemics in the locality tested and other areas with similar or lower transmission

Expansion of anti-AFP Th1 and Tc1 responses in hepatocellular carcinoma occur in different stages of disease

Copyright @ 2010 Cancer Research UK. This work is licensed under the Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/.Background: α-Fetoprotein (AFP) is a tumour-associated antigen in hepatocellular carcinoma (HCC) and is a target for immunotherapy. However, there is little information on the pattern of CD4 (Th1) and CD8 (Tc1) T-cell response to AFP in patients with HCC and their association with the clinical characteristics of patients. Methods: We therefore analysed CD4 and CD8 T-cell responses to a panel of AFP-derived peptides in a total of 31 HCC patients and 14 controls, using an intracellular cytokine assay for IFN-γ. Results: Anti-AFP Tc1 responses were detected in 28.5% of controls, as well as in 25% of HCC patients with Okuda I (early tumour stage) and in 31.6% of HCC patients with stage II or III (late tumour stages). An anti-AFP Th1 response was detected only in HCC patients (58.3% with Okuda stage I tumours and 15.8% with Okuda stage II or III tumours). Anti-AFP Th1 response was mainly detected in HCC patients who had normal or mildly elevated serum AFP concentrations (P=0.00188), whereas there was no significant difference between serum AFP concentrations in these patients and the presence of an anti-AFP Tc1 response. A Th1 response was detected in 44% of HCC patients with a Child–Pugh A score (early stage of cirrhosis), whereas this was detected in only 15% with a B or C score (late-stage cirrhosis). In contrast, a Tc1 response was detected in 17% of HCC patients with a Child–Pugh A score and in 46% with a B or C score. Conclusion: These results suggest that anti-AFP Th1 responses are more likely to be present in patients who are in an early stage of disease (for both tumour stage and liver cirrhosis), whereas anti-AFP Tc1 responses are more likely to be present in patients with late-stage liver cirrhosis. Therefore, these data provide valuable information for the design of vaccination strategies against HCC.Association for International Cancer Research and Polkemmet Fund, London Clinic

RECOMENDACIÓN DINÁMICA DE N EN MAÍZ BASADO EN LA PREDICCIÓN DEL AGUA TRANSPIRADA

The objective of the present work is to study the stability of the relationship between N absorbed and water transpired in order to explore new tools for predicting nitrogen fertilization needs based on the prediction of N demand by this route. If this tool is reliable and can be extrapolated to different environments, it would be very useful for rational and efficient use of N in scenarios of different water availability.El objetivo del presente trabajo es estudiar la estabilidad de la relación entre el N absorbido y el agua transpirada para luego explorar nuevas herramientas de predicción de necesidades de fertilización nitrogenada basadas en la predicción de la demanda de N por esta vía. De ser una herramienta confiable y extrapolable a diferentes ambientes, sería de gran utilidad para utilizar de forma racional y eficiente del N ante escenarios de diferente disponibilidad hídrica