3,829 research outputs found
Measurement of macroscopic plasma parameters with a radio experiment: Interpretation of the quasi-thermal noise spectrum observed in the solar wind
The ISEE-3 SBH radio receiver has provided the first systematic observations of the quasi-thermal (plasma waves) noise in the solar wind plasma. The theoretical interpretation of that noise involves the particle distribution function so that electric noise measurements with long antennas provide a fast and independent method of measuring plasma parameters: densities and temperatures of a two component (core and halo) electron distribution function have been obtained in that way. The polarization of that noise is frequency dependent and sensitive to the drift velocity of the electron population. Below the plasma frequency, there is evidence of a weak noise spectrum with spectral index -1 which is not yet accounted for by the theory. The theoretical treatment of the noise associated with the low energy (thermal) proton population shows that the moving electrical antenna radiates in the surrounding plasma by Carenkov emission which becomes predominant at the low frequencies, below about 0.1 F sub P
Pericarditis Revealing Large Vessel Vasculitis
Large vessels vasculitis and more specifically, Giant cell arteritis, is characterized by increased inflammatory markers, headaches and altered clinical status. Diagnosis is confirmed by biopsy of temporal arteries showing the presence of granuloma and vasculitis. We hereby report the case of a patient presenting initially as pericarditis and revealing large vessel vasculitis using FDG-PET
Insectos plaga del arroz en Loreto, Amazonia peruana
The rice is extensively cultivated on the bank of the Ucayali River in the Peruvian Amazonia. Some plantations have been visited and sampled to make an inventory of the phytofagous insects of this crop. Fifteen species of pests of rice are reported. Three of them are considered as potentially dangerous for the rice in this region : #Diatraea saccharalis F., #Oebaleus poecilus Dallas and #Tibraca limbativentris$ Stal. (Résumé d'auteur
Relative contribution of decreased productivity and survival to recent changes in the demographic trend of the Rivière George Caribou Herd
The Rivière George caribou herd (RGCH) was numerically low during the middle part of the century but apparently erupted in the sixties and the seventies. Puberty was early and pregnancy rate was high among RGCH females from 1973 until the mid-eighties when fecundity decreased significantly, in particular among sub-adults; productivity remained low in 1992. Autumn calf:female ratios reflected this trend in pregnancy, exceeding 50 calves: 100 cows between 1973 and 1983, but dropping thereafter progressively to a low of 24 in 1992. In 1993, this ratio rebounded back to 42. Annual adult survival rate of radio-collared females was high (0.95) at the beginning of the monitoring in 1984, but exhibited a variable but declining trend until 1992. Simulations were conducted to estimate the demographic trend of the RGCH between 1984 and 1992, using annual survival rates of radio-collared animals and annual autumn calffemale ratios to estimate calf production. Age structure played a minor role in estimating the finite rate of increase (Lamda). According to the simulations, the RGCH increased in size until 1987, and showed a slight decrease thereafter. The herd should have decreased by 12-15% between 1988 and 1993, according to the simulations. Productivity first caused a decline in Lamda, but in recent years decreased survival contributed slightly more than productivity to the reduction in Lamda. Estimation of the herd size by means of aerial censuses in 1976, 1984, 1988 and 1993 suggested a similar pattern in demographic trend, differences being statistically meaningless. We speculated on the future of the RGCH, that could have erupted after many decades of unfavourable weather. The herd will exhibit a rapid descent to low numbers if wolves show a numerical response to current caribou abundance, or if lichen availability on the winter range decreases due to competition with the adjacent and increasing Rivière aux Feuilles herd; otherwise it will exhibit dampened oscillations, whose amplitude will depend on the time-lag of vegetation reaction to decrease grazing pressure on the summer range
Besouros nocivos Ă bacabeira: Dynamis borassi e Foveolus aterpes.
bitstream/item/39861/1/Com-Tec-19-Am-Oriental.pd
Entomofauna fitĂłfaga em palmeiras nativas da AmazĂ´nia.
bitstream/item/52974/1/PesquisaAnd020001.pd
Insetos visitantes e polinizadores em palmeiras nativas da AmazĂ´nia.
bitstream/item/57864/1/Oriental-PA1.pd
Avaliação do ataque do besouro Dynamis borassi na coleção de germoplasma de bacabinha.
bitstream/item/39894/1/Com-Tec-30-Am-Oriental.pd
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