Global perspectives on observing ocean boundary current systems

Ocean boundary current systems are key components of the climate system, are hometo highly productive ecosystems, and have numerous societal impacts. Establishmentof a global network of boundary current observing systems is a critical part of ongoingdevelopment of the Global Ocean Observing System. The characteristics of boundarycurrent systems are reviewed, focusing on scientific and societal motivations forsustained observing. Techniques currently used to observe boundary current systemsare reviewed, followed by a census of the current state of boundary current observingsystems globally. The next steps in the development of boundary current observingsystems are considered, leading to several specific recommendations

Efeitos do alcoolismo e da desintoxicação alcoólica sobre o reparo e biomecânica óssea Effects of alcoholism and alcoholic detoxication on the repair and biomechanics of bone

OBJETIVO: Avaliar os efeitos do consumo crônico de etanol e da desintoxicação alcoólica sobre a resistência mecânica do osso e neoformação óssea junto a implantes de hidroxiapatita densa (HAD) realizados em ratos. MÉTODOS: Foram utilizados 15 ratos divididos em três grupos, sendo controle (CT), alcoolista crônico (AC) e desintoxicado (DE). Após quatro semanas, foi realizada implantação de HAD na tíbia e produzida falha no osso parietal, em seguida o grupo AC continuaram a consumir etanol e o grupo DE iniciaram a desintoxicação. Ao completar 13 semanas os animais sofreram eutanásia, os ossos foram coletados para o processamento histomorfométrico e os fêmures encaminhados ao teste mecânico de resistência. RESULTADOS: Os animais do grupo AC apresentaram menores valores de neoformação óssea, de calcemia e resistência mecânica, quando comparado aos grupos CT e DE. Os animais dos grupos DE apresentaram valores superiores em todas as variáveis avaliadas em relação ao grupo AC. CONCLUSÃO: O consumo de etanol interferiu na osteogênese ao redor de implante de HAD, nos níveis de cálcio e na resistência mecânica óssea. A desintoxicação alcoólica se mostrou eficaz, pois aumentou à osteogênese e osseointegração da HAD, a calcemia e resistência mecânica óssea. Nivel de Evidência I, estudo terapeutico.<br>OBJECTIVE: To evaluate the effects of chronic ethanol consumption and alcohol detoxication on the mechanical resistance of bone and bone neoformation around dense hydroxyapatite implants (DHA) in rats. METHODS: Fifteen rats were separated into three groups: (1) control group (CT); (2) chronic alcoholic (CA), and (3) disintoxicated (DI). After four weeks, a DHA was implanted in the right tibia of the animals, and the CA group continued consuming ethanol, while the DI group started detoxication. The solid and liquid feeding of the animals was recorded, and a new alcohol dilution was effected every 48 hours. After 13 weeks, the animals were euthanized and their biological material was collected. RESULTS: Bone tissue was found around DHA in all the animals. Group CA showed less bone neoformation, lower levels of ionic and total calcium when compared to the animals of the CT and DI groups. The DI animals showed higher values in all the variables in relation to the CA group. CONCLUSION: Ethanol consumption interfered in osteogenesis around the DHA implants, and in calcium levels and mechanical bone resistance. Alcohol detoxication was effective, as it increased osteogenesis, DHA osteointegration, calcemia, and mechanical resistance of the bone. Level of Evidence: Level I, therapeutic studie

Complex geophysical wake flows

Idealized studies of island wakes often use a cylinder-like island to generate the wake, whereas most realistic studies use a close representation of the oceanic bathymetry immersed in a complex representation of the "ambient" geophysical flows. Here, a system of multiple islands was placed into numerical and experimental channels, in order to focus on the complexity of the archipelago wake, including (a) the influence of small neighboring islands and (b) the role of the island-shelf. The numerical geostrophic and stratified channel was built using a three-dimensional primitive equation model, considering a realistic representation of the Madeira archipelago bathymetry, with prescribed initial and boundary conditions. Results from the simulations show that the neighboring islands alter the near-field wake. Small eddies generated by the neighboring islands lead to destabilization of the shear layers of the larger island. Laboratory experiments carried out in the Coriolis rotating tank corroborated this near-field disruptive mechanism. The neighboring island perturbation effect was present whatever the direction of the incoming flow, but under different regimes. North-south wakes produced geostrophic eddies (a parts per thousand yen R (d)), whereas west-east wakes produced (exclusively) ageostrophic submesoscale eddies (< < R (d)) which traveled offshore with wave-like motion. The archipelago shelf contributed to the asymmetric vertical migration of oceanic vorticity. Cyclonic vorticity dominated the surface dynamics, whereas anticyclonic circulation prevailed at the bottom part of the linearly stratified upper layer. This study identifies several likely wake scenarios induced by the Madeira archipelago, and may serve as guide for future multiscale numerical studies and in situ campaigns.700683181,2031,761Q2Q2SCI