3,448 research outputs found
Management Effect on Rainfall Use Efficiency and Growth Rate of Spineless Cactus \u3cem\u3ecv.\u3c/em\u3e Miúda in Northeast Brazil
Spineless cactus has a high rainfall use efficiency. Under water deficit, they open their stomata during the night to capture atmospheric carbon dioxide when the air temperature is lower and relative humidity higher (Taiz and Zeiger, 2009), losing less water to the atmosphere. The rainfall use efficiency (RUE) can be expressed as the amount of water used by the crop to produce dry matter (Han and Felker, 1997). The RUE showed by spineless cactus, a CAM plant, is three to five times greater than the one observed in C3 and C4 plants (Felker and Russel, 1988; Nobel, 1991). Therefore, spineless cacti (Nopaleae opuntia) are important forage resource in northeast Brazil. Management practices, however, can affect the RUE and growth of spineless cactus, especially organic and mineral fertilization. Thus, the objective of this research was to evaluate the effect of organic and nitrogen fertilization and harvest frequency on rainfall use efficiency and growth rate of spineless cactus cv. Miúda (Nopalea cochenillifera Salm Dyck)
Characterization of Systemic Disease Development and Paw Inflammation in a Susceptible Mouse Model of Mayaro Virus Infection and Validation Using X-ray Synchrotron Microtomography
Mayaro virus (MAYV) is an emerging arthropod-borne virus endemic in Latin America and the causative agent of arthritogenic febrile disease. Mayaro fever is poorly understood; thus, we established an in vivo model of infection in susceptible type-I interferon receptor-deficient mice (IFNAR−/−) to characterize the disease. MAYV inoculations in the hind paws of IFNAR−/− mice result in visible paw inflammation, evolve into a disseminated infection and involve the activation of immune responses and inflammation. The histological analysis of inflamed paws indicated edema at the dermis and between muscle fibers and ligaments. Paw edema affected multiple tissues and was associated with MAYV replication, the local production of CXCL1 and the recruitment of granulocytes and mononuclear leukocytes to muscle. We developed a semi-automated X-ray microtomography method to visualize both soft tissue and bone, allowing for the quantification of MAYV-induced paw edema in 3D with a voxel size of 69 µm3. The results confirmed early edema onset and spreading through multiple tissues in inoculated paws. In conclusion, we detailed features of MAYV-induced systemic disease and the manifestation of paw edema in a mouse model extensively used to study infection with alphaviruses. The participation of lymphocytes and neutrophils and expression of CXCL1 are key features in both systemic and local manifestations of MAYV disease
Efeitos da adubação orgânica e da época de colheita na qualidade da matéria-prima e nos rendimentos agrícola e de açúcar mascavo artesanal de duas cultivares de cana-de-açúcar (cana-planta).
Conduziu-se este trabalho com o objetivo de estudar os efeitos de três sistemas de adubação (30 t. ha-1 de esterco de curral, 3,5 t.ha-1 de esterco de galinha e adubação química - 120 kg.ha-1 de P2O5 e de K2O no plantio + 60 kg.ha-1 de N em cobertura) e três épocas de colheita da cana (julho, agosto e setembro de 2003), na qualidade da matéria-prima e nos rendimentos de colmos e de açúcar mascavo de duas cultivares de cana-de-açúcar (SP79-1011 e RB72454). O experimento foi instalado em área do Alambique JM, Perdões, MG. O delineamento experimental foi o de blocos casualizados, em esquema fatorial (2 x 3 x 3), com três repetições. Não houve efeito dos fertilizantes nos rendimentos de colmos e de açúcar mascavo das cultivares estudadas. Verificou-se efeito de épocas de colheita no rendimento de colmos, com destaque para os meses de agosto e setembro. No entanto, para rendimento de açúcar mascavo nenhuma diferença foi observada. Assim, nas condições deste trabalho, é viável a substituição da adubação química pela orgânica (esterco de curral ou de galinha), sem perdas na qualidade da matéria-prima e nos rendimentos de colmos e de açúcar mascavo artesanal, sendo que os meses de agosto e setembro foram os que proporcionaram matéria-prima de melhor qualidade e maiores rendimentos de colmos
Theory of Functional Connections and Nelder-Mead optimization methods applied in satellite characterization
The growing population of man-made objects with the build up of
mega-constellations not only increases the potential danger to all space
vehicles and in-space infrastructures (including space observatories), but
above all poses a serious threat to astronomy and dark skies. Monitoring of
this population requires precise satellite characterization, which is is a
challenging task that involves analyzing observational data such as position,
velocity, and light curves using optimization methods. In this study, we
propose and analyze the application of two optimization procedures to determine
the parameters associated with the dynamics of a satellite: one based on the
Theory of Functional Connections (TFC) and another one based on the Nelder-Mead
heuristic optimization algorithm. The TFC performs linear functional
interpolation to embed the constraints of the problem into a functional. In
this paper, we propose to use this functional to analytically embed the
observational data of a satellite into its equations of dynamics. After that,
any solution will always satisfy the observational data. The second procedure
proposed in this research takes advantage of the Nealder-Mead algorithm, that
does not require the gradient of the objective function, as alternative
solution. The accuracy, efficiency, and dependency on the initial guess of each
method is investigated, analyzed, and compared for several dynamical models.
These methods can be used to obtain the physical parameters of a satellite from
available observational data and for space debris characterization contributing
to follow-up monitoring activities in space and astronomical observatories.Comment: Submitted to Acta Astronautic
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