`Candidatus Liberibacter asiaticus´ titers in citrus and acquisition rates by Diaphorina citri are decreased by higher temperature

`Candidatus Liberibacter asiaticus´ is the most prevalent Liberibacter sp. associated with huanglongbing (HLB) in Brazil. Within São Paulo state (SP), HLB has spread more rapidly to and reached higher incidence in regions with relatively mild (cooler) summer temperatures. This suggests that climate can influence disease spread and severity. ?Ca. L. asiaticus? titers on soft, immature leaves from infected ?Valencia? sweet orange plants exposed to different temperature regimes and adult Diaphorina citri fed for 48 h on these plants for ?Ca. L. asiaticus? acquisition were determined by quantitative polymerase chain reaction in two experiments. The first experiment included plants with three levels of infection, three incubation periods (IPs), and air temperatures favorable (14.6 to 28°C) and unfavorable (24 to 38°C) to ?Ca. L. asiaticus?. The second included plants with severe late-stage infections, 10 IPs (based on 3-day intervals over 27 days), and three air temperature regimes (12 to 24, 18 to 30, and 24 to 38°C). Overall, ?Ca. L. asiaticus? titers and the percentages of ?Ca. L. asiaticus?-positive psyllids were lower in plants maintained at the warmer temperature regime (24 to 38°C) than in plants maintained in the cooler regimes. The results suggest that the lower incidence and slower spread of ?Ca. L. asiaticus? to warmer regions of SP are related to the influence of ambient temperatures on titers of ?Ca. L. asiaticus? in leaves.

Riesgos de taludes y terraplenes en obras lineales de la República Dominicana

Partiendo de la idea de la concurrencia de un fenómeno y de las acciones que se deben llevar a cabo, se debe entender la Gestión de Riesgos como una determinación de relaciones entre lo que se asume como vulnerable, y la forma en la cual se estimará la probabilidad de un determinado hecho. A medida en que pasa el tiempo, se torna más importante el tema de vulnerabilidad y de riesgo a nivel mundial. La vulnerabilidad se vuelve más notoria ante la presencia de determinados peligros naturales como lo son los siguientes: deslizamientos de tierras, movimientos sísmicos, desbordes de ríos e inundaciones. (Pérez Soriano, 2014) La vulnerabilidad se ve en su mayoría más afectada por acciones antrópicas como lo son la construcción de viviendas en lugares de alto riesgo, como por ejemplo, viviendas en los taludes de obras lineales. Estas viviendas están condicionadas por la localización, el uso del suelo, la infraestructura, la distribución y la densidad de la población, su capacidad de organización, etc. La Gestión de Riesgos se vuelve cada vez más exigente en cuanto a la calidad de los servicios ofertados, además de también, cumplir con la responsabilidad jurídica que implica la concepción, diseño y construcción de taludes y terraplenes en obras lineales. (Pérez Soriano, 2014) El presente trabajo de investigación se centra en la identificación y valoración de los riesgos de taludes y terraplenes en obras lineales de la República Dominicana. De esta manera se busca disminuir el riesgo de la rotura o fallo de un talud o terraplén, y el número de víctimas que puedan ser afectadas por el mismo, concluyendo con un catálogo de riesgos para taludes y terraplenes en obras lineales. Based on the idea of the occurrence of a phenomenon and the actions to be carried out, Risk Management should be understood as a determination of relationships between what is assumed to be vulnerable, and the way in which the probability of a particular event will be estimated. The issue of vulnerability and risk becomes more important worldwide as time goes on. Vulnerability becomes more evident in the presence of certain natural hazards such as: landslides, earthquakes, overflowing rivers and flooding. (Pérez Soriano, 2014) It has become evident that vulnerability is mostly affected by human actions, such as the construction of housing in high-risk locations, for example, man-made slopes. These properties are conditioned by the location, land use, infrastructure, distribution and density of the population, organizational skills, etc. Risk management is becoming more discerning about the quality of the services offered, in addition to the compliance of the legal responsibility that the conception, design and construction of slopes and embankments in linear works require. (Pérez Soriano, 2014) This research project focuses on the identification and valuation of the risks derived from slopes and embankments in linear works of the Dominican Republic, in order to reduce the risks of failure of a slope or embankment and the number of victims who may be affected from it. Concluding with a risk catalogue for slopes and embankments in linear works.