The Impact of Accurate Extinction Measurements for X-ray Spectral Models

Interstellar extinction includes both absorption and scattering of photons from interstellar gas and dust grains, and it has the effect of altering a source's spectrum and its total observed intensity. However, while multiple absorption models exist, there are no useful scattering models in standard X-ray spectrum fitting tools, such as XSPEC. Nonetheless, X-ray halos, created by scattering from dust grains, are detected around even moderately absorbed sources and the impact on an observed source spectrum can be significant, if modest, compared to direct absorption. By convolving the scattering cross section with dust models, we have created a spectral model as a function of energy, type of dust, and extraction region that can be used with models of direct absorption. This will ensure the extinction model is consistent and enable direct connections to be made between a source's X-ray spectral fits and its UV/optical extinction.Comment: 8 pages, 4 figure

Conceptos basicos sobre patologia del frijol

The most important bean diseases in Latin America are listed and the events that occur during the disease cycle are described: inoculation, penetration, infection, and release or dissemination of the pathogen. Disease management or control is also described; this depends on economic, environmental, physical, and biological factors. Information is given on control methods and some selection criteria, emphasizing genetic resistance (vertical, horizontal, and combinations). (CIAT)Se enumeran las enfermedades del frijol mas importantes en America Latina y se describen los diferentes eventos que se presentan en el ciclo de las enfermedades: inoculacion, penetracion, infeccion y liberacion o diseminacion del patogeno. Se describe tambien el manejo o control de las enfermedades, el cual depende de factores economicos, ambientales, fisicos y biologicos. Se informa sobre los metodos de control y algunos criterios de seleccion, con enfasis en la resistencia genetica (vertical, horizontal y combinaciones). (CIAT

Enfermedades del frijol causadas por bacterias

The etiology, symptomatology, cultural and chemical control measures, and general aspects of control through var. resistance to bean diseases are described for the bacterial pathogens Pseudomonas syringae pv. phaseolicola and Xanthomonas campestris pv. phaseoli. Some var. resistant to these pathogens are listed. (CIAT)Se describen la etiologia, sintomatologia, medidas de control cultural y quimico, y aspectos generales de control por resistencia var. de las enfermedades del frijol causadas por los patogenos bacterianos Pseudomonas syringae pv. phaseolicola y Xanthomonas campestris pv. phaseoli. Se mencionan algunas var. resistentes a estos patogenos. (CIAT

Enfermedades del frijol causadas por hongos

The etiology, symptomatology, cultural and chemical control measures, and general aspects of control through var. resistance to bean diseases are described for the following fungal pathogens: Uromyces phaseoli, Colletotrichum lindemuthianum, Isariopsis griseola, Rhizoctonia solani, Ascochyta phaseolorum, Macrophomina phaseoli, Fusarium solani phaseoli, F. oxysporum, and Pythium sp. A list of the check var. of the International Bean Rust Nursery (with broad resistance to the pathogen), evaluated during 1975-85, is included. (CIAT)Se describen la etiologia, sintomatologia, medidas de control cultural y quimico, y aspectos generales de control por resistencia var. de las enfermedades del frijol causadas por los patogenos fungicos Uromyces phaseoli, Colletotrichum lindemuthianum, Isariopsis griseola, Rhizoctonia solani, Ascochyta phaseolorum, Macrophomina phaseoli, Fusarium solani phaseoli, F. oxysporum y Pythium sp. Se incluye tambien una lista de var. testigo del Vivero Internacional de la Roya del Frijol (con amplia resistencia al patogeno) evaluadas durante 1975-85. (CIAT

Rust

Bean rust (Uromyces phaseoli), a common disease with worldwide distribution, is considered one of the most important bean production problems in the tropics. Prolonged periods of moisture and moderate temp. (17-27 degrees C) favor disease development. The infection process begins when a urediospore produces a germ tube, which develops an appressorium after physical contact with the edges of a stomata. The fungus may infect leaves and pods, and rarely stems and branches. For efficient disease control, cultural practices, crop rotation, elimination of harvest debris, biological control, the utilization of chemical products during the initial stages of plant development, and the use of resistant var. are recommended. A table is included on differential var. and infection rates used by different investigators to identify physiological races of this pathogen. Symptoms and damage caused by the disease are illustrated in color. (CIAT)La roya del frijol (Uromyces phaseoli) es una enfermedad a nivel mundial considerada como uno de los problemas mas importantes de la produccion de frijol en el tropico. Periodos prolongados de humedad y temp. moderadas (17-27 grados C) favorecen el desarrollo de la enfermedad. El proceso de infeccion empieza cuando una uredospora produce el tubo germinativo, el cual desarrolla un apresorio despues de establecer el contacto fisico con los bordes de un estoma. El hongo puede infectar hojas y vainas, y algunas veces los tallos y ramas. Para un buen control de la enfermedad se recomiendan practicas culturales (rotacion de cultivos, eliminacion de residuos de cosecha), control biologico, utilizacion de productos quimicos durante las etapas iniciales de desarrollo de la planta y el uso de var. resistentes. En forma de cuadro se incluyen las var. diferenciales y los grados de infeccion utilizados por los diferentes investigadores en la identificacion de las razas fisiologicas del patogeno. Se ilustran a color los sintomas y danos causados por la enfermedad. (CIAT

Anthracnose

Bean anthracnose, caused by the fungus Colletotrichum lindemuthianum, is a worldwide disease in susceptible var. grown in locations with cool to moderate temp. and with a high RH. It can appear anywhere in the plant. Losses can be up to 100 percent when severely infected seed is planted. For efficient disease control, the production of disease-free seed, crop rotations, utilization of adequate chemical products, and the use of resistent var. are recommended. The symptoms and damage caused by the disease are illustrated in color. (CIAT)La antracnosis del frijol, causada por el hongo Colletotrichum lindemuthianum, es una enfermedad que se presenta en todo el mundo en las var. susceptibles establecidas en localidades con temp. moderadas-frias y con alta HR ambiental. Puede aparecer en cualquier parte de la planta. Las perdidas pueden ser del 100 por ciento cuando se siembra semilla severamente infectada. Para un buen control de la enfermedad se recomiendan la produccion de semilla libre del patogeno, rotacion de cultivos, utilizacion de productos quimicos adecuados y var. resistentes. Se ilustran a color los sintomas y danos causados por la enfermedad. (CIAT

The Role of SepF in Cell Division and Diazotrophic Growth in the Multicellular Cyanobacterium Anabaena sp. Strain PCC 7120

The cyanobacterium Anabaena forms filaments of cells that grow by intercalary cell division producing adjoined daughter cells connected by septal junction protein complexes that provide filament cohesion and intercellular communication, representing a genuine case of bacterial multicellularity. In spite of their diderm character, cyanobacterial genomes encode homologs of SepF, a protein normally found in Gram-positive bacteria. In Anabaena, SepF is an essential protein that localized to the cell division ring and the intercellular septa. Overexpression of sepF had detrimental effects on growth, provoking conspicuous alterations in cell morphology that resemble the phenotype of mutants impaired in cell division, and altered the localization of the division-ring. SepF interacted with FtsZ and with the essential FtsZ tether ZipN. Whereas SepF from unicellular bacteria generally induces the bundling of FtsZ filaments, Anabaena SepF inhibited FtsZ bundling, reducing the thickness of the toroidal aggregates formed by FtsZ alone and eventually preventing FtsZ polymerization. Thus, in Anabaena SepF appears to have an essential role in cell division by limiting the polymerization of FtsZ to allow the correct formation and localization of the Z-ring. Expression of sepF is downregulated during heterocyst differentiation, likely contributing to the inhibition of Z-ring formation in heterocysts. Finally, the localization of SepF in intercellular septa and its interaction with the septal-junction related proteins SepJ and SepI suggest a role of SepF in the formation or stability of the septal complexes that mediate cell-cell adhesion and communication, processes that are key for the multicellular behavior of Anabaena.Ministerio de Ciencia e Innovación PID2020-118595GB-10