974 research outputs found
Soluble CD40 ligand can replace the normal T cell-derived CD40 ligand signal to B cells in T cell-dependent activation
We have constructed a soluble chimeric fusion protein between the mouse CD8 alpha chain and the mouse CD40 T cell ligand. This protein binds to both human and mouse B cells. By itself it induced a modest degree of B cell proliferation, but together with anti-immunoglobulin (anti-Ig) antibody it greatly stimulated B cell proliferation, as determined by both [3H]thymidine uptake and increase in cell numbers. These data are evidence that the CD40 ligand on T cells provides a signal that drives B cell proliferation. This signal is synergistic with that delivered by anti-Ig antibody
Mercury's Internal Structure
We describe the current state of knowledge about Mercury's interior
structure. We review the available observational constraints, including mass,
size, density, gravity field, spin state, composition, and tidal response.
These data enable the construction of models that represent the distribution of
mass inside Mercury. In particular, we infer radial profiles of the pressure,
density, and gravity in the core, mantle, and crust. We also examine Mercury's
rotational dynamics and the influence of an inner core on the spin state and
the determination of the moment of inertia. Finally, we discuss the
wide-ranging implications of Mercury's internal structure on its thermal
evolution, surface geology, capture in a unique spin-orbit resonance, and
magnetic field generation.Comment: 36 pages, 11 figures, in press, to appear in "Mercury - The View
after MESSENGER", S. C. Solomon, B. J. Anderson, L. R. Nittler (editors),
Cambridge University Pres
Bifunctional Lewis and Brønsted acidic zeolites permit the continuous production of bio-renewable furanic ethers
The catalytic valorisation of bio-renewable feedstock often relies upon multi-stage processing of highly-functionalised substrates, resulting in selectivity and processs engineering challenges. Herein, we demonstrate that a bifunctional zeolitic material, containing both Lewis and Brønsted acid sites in a single catalytic material, permits the continuous production of bio-renewable furanic ethers, such as (butoxy)methyl furan, which possess potential as fuel additives. In contrast to mono-functional catalysts and physical mixtures thereof, the bifunctional Sn- and Al-containing BEA zeolite results in uniquely-high levels of activity, selectivity and stability. Optimal results were obtained over a bifunctional catalyst containing 2 wt.% Sn and 0.5 wt.% Al, prepared by modified solid state incorporation, which was highly selective (> 75 %) to the deisred ether for over 107 h on stream, and for over 3000 substrate turnovers
Mercury's low‐degree geoid and topography controlled by insolation‐driven elastic deformation
©2015. American Geophysical UnionMercury experiences an uneven insolation that leads to significant latitudinal and longitudinal variations of its surface temperature. These variations, which are predominantly of spherical harmonic degrees 2 and 4, propagate to depth, imposing a long‐wavelength thermal perturbation throughout the mantle. We computed the accompanying density distribution and used it to calculate the mechanical and gravitational response of a spherical elastic shell overlying a quasi‐hydrostatic mantle. We then compared the resulting geoid and surface deformation at degrees 2 and 4 with Mercury's geoid and topography derived from the MErcury, Surface, Space ENvironment, GEochemistry, and Ranging spacecraft. More than 95% of the data can be accounted for if the thickness of the elastic lithosphere were between 110 and 180 km when the thermal anomaly was imposed. The obtained elastic thickness implies that Mercury became locked into its present 3:2 spin orbit resonance later than about 1 Gyr after planetary formation
The thermal state and interior structure of Mars
©2018. American Geophysical UnionThe present‐day thermal state, interior structure, composition, and rheology of Mars can be constrained by comparing the results of thermal history calculations with geophysical, petrological, and geological observations. Using the largest‐to‐date set of 3‐D thermal evolution models, we find that a limited set of models can satisfy all available constraints simultaneously. These models require a core radius strictly larger than 1,800 km, a crust with an average thickness between 48.8 and 87.1 km containing more than half of the planet's bulk abundance of heat producing elements, and a dry mantle rheology. A strong pressure dependence of the viscosity leads to the formation of prominent mantle plumes producing melt underneath Tharsis up to the present time. Heat flow and core size estimates derived from the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission will increase the set of constraining data and help to confine the range of admissible models.DFG, 280637173, FOR 2440: Materie im Inneren von Planeten - Hochdruck-, Planeten- und Plasmaphysi
Viabilidade econômica da produção agroecológica de hortaliças no Sistema de Produção Agroecológica Integrada e Sustentável (PAIS) em Juti, Mato Grosso do Sul.
Publicado também na: Revista Brasileira de Agroecologia, v. 6. n. 2, dez. 2011
Nível de adoção de boas práticas em sistemas de produção sob transição agroecológica no Sul de Mato Grosso do Sul.
bitstream/item/66257/1/31295.pdfOrganizado por: Alberto Feiden, Milton Parron Padovan, Adalgiza Inês Campolim, Aurélio Vinícius Borsato, Ivo de Sá Motta, João Batista Catto, Tércio Jacques Fehlauer
Genótipos de mandioca de mesa submetidos a manejo orgânico em diferentes regiões no Mato Grosso do Sul.
Publicado também na: RAT: Revista Raízes e Amidos Tropicais, v. 3, 2007. (SEP 034)
Evaluación de proyectos de inversión en pandemia. Acercamiento a su problemática en las pymes argentinas
La economía argentina se ha caracterizado históricamente por sucesivos periodos de inestabilidad marcada en las principales variables macroeconómicas lo que suscita la generación de un contexto volátil donde la incertidumbre enmarca cualquier toma de decisión económica y financiera. Este contexto se ha visto amplificado a partir de la declaración de pandemia por el avance del virus Covid-19, redundando en numerosas dificultades para las empresas Pymes argentinas al momento de poder planificar y evaluar sus proyectos de inversión. El objetivo de esta ponencia es enumerar los principales desafíos con los cuales se enfrentan los empresarios Pymes a la hora de tomar decisiones de inversión y desarrollar algunas herramientas financieras disponibles para morigerar el impacto sobre la rentabilidad financiera del negocio y tener la posibilidad de transitar el contexto de pandemia con éxito.--Fil: Padovan, Alex A. Universidad Nacional Villa María; Argentina.
Trajetória de um agricultor-multiplicador na agroecologia: uma experiência a ser seguida no âmbito da agricultura familiar.
Publicado também em: Cadernos de Agroecologia, v. 11, n. 2, 2016
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