128 research outputs found
Doenças em bovinos confinados.
Botulismo; Enterotoxemia. Dermatomicose. Dermatofilose. Timpanismo. Acidose láctica. Laminite. Intoxicação por uréia.bitstream/item/135848/1/DOC-65.pd
"Breathing" rogue wave observed in numerical experiment
Numerical simulations of the recently derived fully nonlinear equations of
motion for weakly three-dimensional water waves [V.P. Ruban, Phys. Rev. E {\bf
71}, 055303(R) (2005)] with quasi-random initial conditions are reported, which
show the spontaneous formation of a single extreme wave on the deep water. This
rogue wave behaves in an oscillating manner and exists for a relatively long
time (many wave periods) without significant change of its maximal amplitude.Comment: 6 pages, 12 figure
The importance of plants for methane emission at the ecosystem scale
Methane (CH4), one of the key long-lived atmospheric greenhouse gases, is primarily produced from organic matter. Accordingly, net primary production of organic matter sets the boundaries for CH4 emissions. Plants, being dominant primary producers, are thereby indirectly sustaining most global CH4 emissions, albeit with delays in time and with spatial offsets between plant primary production and subsequent CH4 emission. In addition, plant communities can enhance or hamper ecosystem production, oxidation, and transport of CH4 in multiple ways, e.g., by shaping carbon, nutrient, and redox gradients, and by representing a physical link be-tween zones with extensive CH4 production in anoxic sediments or soils and the atmosphere. This review focuses on how plants and other primary producers influence CH4 emissions with the consequences at ecosystem scales. We outline mechanisms of interactions and discuss flux regulation, quantification, and knowledge gaps across multiple ecosystem examples. Some recently proposed plant-related ecosystem CH4 fluxes are difficult to reconcile with the global atmospheric CH4 budget and the enigmas related to these fluxes are highlighted. Overall, ecosystem CH4 emissions are strongly linked to primary producer communities, directly or indirectly, and properly quantifying magnitudes and regulation of these links are key to predicting future CH4 emissions in a rapidly changing world.Funding Agencies|European Research Council (ERC) [725546]; Swedish Research Councils VR [2016-04829]; Formas [2018- 01794, 2018-00570]; ERC H2020 [851181]; Helmholtz Impulse and Networking Fund; UK NERC [NE/J010928/1, NE/N015606/1]; AXA Research Fund [426]; Royal Society; Royal Society Dorothy Hodgkin Research Fellowship [DH160111]; Swedish Research Council Formas [2021-02429]</p
Plataforma para compartilhamento de dados de pesquisa em agricultura de precisão.
Resumo: Este trabalho descreve a experiência de utilização da plataforma GeoNode para o compartilhamento de dados de pesquisa da Rede de Agricultura de Precisão da Embrapa. A plataforma se mostrou uma boa solução, principalmente para o compartilhamento de dados vetoriais. Para imagens com alta resolução espacial, algumas melhorias são necessárias, principalmente com relação à obtenção dos dados por parte dos usuários autorizados.Editores: Paulino Ribeiro Villas-Boas, Maria Alice Martins, Débora Marcondes Bastos Pereira Milori, Ladislau Martin Neto. SIAGRO 2019
A strong CO<sub>2</sub> sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil)
In contrast to its small surface area,
the coastal zone plays a disproportionate role in the global carbon cycle.
Carbon production, transformation, emission and burial rates at the
land–ocean interface are significant at the global scale but still poorly
known, especially in tropical regions. Surface water pCO2 and
ancillary parameters were monitored during nine field campaigns between
April 2013 and April 2014 in Guanabara Bay, a tropical eutrophic to
hypertrophic semi-enclosed estuarine embayment surrounded by the city of Rio
de Janeiro, southeast Brazil. Water pCO2 varied between 22 and 3715 ppmv in
the bay, showing spatial, diurnal and seasonal trends that mirrored those of
dissolved oxygen (DO) and chlorophyll a (Chl a). Marked pCO2
undersaturation was prevalent in the shallow, confined and thermally
stratified waters of the upper bay, whereas pCO2 oversaturation was
restricted to sites close to the small river mouths and small sewage
channels, which covered only 10 % of the bay's area. Substantial daily
variations in pCO2 (up to 395 ppmv between dawn and dusk) were also
registered and could be integrated temporally and spatially for the
establishment of net diurnal, seasonal and annual CO2 fluxes. In
contrast to other estuaries worldwide, Guanabara Bay behaved as a net sink of
atmospheric CO2, a property enhanced by the concomitant effects of
strong radiation intensity, thermal stratification, and high availability of
nutrients, which promotes phytoplankton development and net autotrophy. The
calculated CO2 fluxes for Guanabara Bay ranged between −9.6 and
−18.3 mol C m−2 yr−1, of the same order of magnitude as the
organic carbon burial and organic carbon inputs from the watershed. The
positive and high net community production (52.1 mol C m−2 yr−1)
confirms the high carbon production in the bay. This autotrophic metabolism is apparently
enhanced by eutrophication. Our results show that global CO2
budgetary assertions still lack information on tropical, marine-dominated
estuarine systems, which are affected by thermal stratification and
eutrophication and behave specifically with respect to atmospheric CO2
Freely decaying weak turbulence for sea surface gravity waves
We study numerically the generation of power laws in the framework of weak
turbulence theory for surface gravity waves in deep water. Starting from a
random wave field, we let the system evolve numerically according to the
nonlinear Euler equations for gravity waves in infinitely deep water. In
agreement with the theory of Zakharov and Filonenko, we find the formation of a
power spectrum characterized by a power law of the form of .Comment: 4 pages, 3 figure
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