Towards an ankle neuroprosthesis for hybrid robotics: Concepts and current sources for functional electrical stimulation.

Hybrid rehabilitation robotics combine neuro-prosthetic devices (close-loop functional electrical stimulation systems) and traditional robotic structures and actuators to explore better therapies and promote a more efficient motor function recovery or compensation. Although hybrid robotics and ankle neuroprostheses (NPs) have been widely developed over the last years, there are just few studies on the use of NPs to electrically control both ankle flexion and extension to promote ankle recovery and improved gait patterns in paretic limbs. The aim of this work is to develop an ankle NP specifically designed to work in the field of hybrid robotics. This article presents early steps towards this goal and makes a brief review about motor NPs and Functional Electrical Stimulation (FES) principles and most common devices used to aid the ankle functioning during the gait cycle. It also shows a current sources analysis done in this framework, in order to choose the best one for this intended application.

Abundance and diversity of phytoplankton in the Paraná River (Argentina) 220 km downstream of the Yacyretá reservoir.

Patterns in the temporal composition, abundance and diversity of the phytoplankton community of the Paraná river prior to and after the initial filling phase of the Yacyretá reservoir are analyzed. The study site is located 220 km downstream from the Yacyretá reservoir and 30 km downstream from the confluence with the Paraguay river. Because both rivers remain separate and unmixed at the study site, we compared the possible effects of the impoundment on both river banks (left and right banks) in hydrological periods with similar duration and magnitude of the low and high water phases. Physical and chemical conditions measured on the right bank (water from the Paraguay river) were similar at both periods (pre and post-impoundment) whereas conductivity, pH and orthophosphate concentration increased on the left bank (water from the High Paraná river and Yacyretá reservoir) after the impoundment. Changes in phytoplankton density and diversity were observed only in samples collected from water flowing from the reservoir (left bank). The density of Chlorophyceae (Chloromonas acidophila, Chlamydomonas leptobasis, Choricystis minor, Chlorella vulgaris, Scenedesmus ecornis, Monoraphidium minutum, M. contortum and M. pusillum) and Cryptophyceae (Rhodomonas minuta, Cryptomonas marssonii and C. ovata) increased while Cyanophyceae (Cylindrospermopsis raciborskii, Raphidiopsis mediterranea and Planktolyngbya subtilis) and Bacillariophyceae (Aulacoseira granulata and its bioforms) decreased compared to previous studies conducted on the left bank of the Paraná river. Phytoplankton collected from the right bank of the river did not differ in pre and post- impoundment samples because they originate from the Paraguay river, which remains relatively unaffected by human activities.

Abundance and diversity of phytoplankton in the Paraná River (Argentina) 220 km downstream of the Yacyretá reservoir

Patterns in the temporal composition, abundance and diversity of the phytoplankton community of the Paraná river prior to and after the initial filling phase of the Yacyretá reservoir are analyzed. The study site is located 220 km downstream from the Yacyretá reservoir and 30 km downstream from the confluence with the Paraguay river. Because both rivers remain separate and unmixed at the study site, we compared the possible effects of the impoundment on both river banks (left and right banks) in hydrological periods with similar duration and magnitude of the low and high water phases. Physical and chemical conditions measured on the right bank (water from the Paraguay river) were similar at both periods (pre and post-impoundment) whereas conductivity, pH and orthophosphate concentration increased on the left bank (water from the High Paraná river and Yacyretá reservoir) after the impoundment. Changes in phytoplankton density and diversity were observed only in samples collected from water flowing from the reservoir (left bank). The density of Chlorophyceae (Chloromonas acidophila, Chlamydomonas leptobasis, Choricystis minor, Chlorella vulgaris, Scenedesmus ecornis, Monoraphidium minutum, M. contortum and M. pusillum) and Cryptophyceae (Rhodomonas minuta, Cryptomonas marssonii and C. ovata) increased while Cyanophyceae (Cylindrospermopsis raciborskii, Raphidiopsis mediterranea and Planktolyngbya subtilis) and Bacillariophyceae (Aulacoseira granulata and its bioforms) decreased compared to previous studies conducted on the left bank of the Paraná river. Phytoplankton collected from the right bank of the river did not differ in pre and post- impoundment samples because they originate from the Paraguay river, which remains relatively unaffected by human activities.

Estudaram-se os padrões temporais de composição, abundância, e diversidade da comunidade fitoplanctônica do Rio Paraná, antes e depois da fase inicial de fechamento do reservatório de Yacyretá (períodos pré e pós-fechamento). A área de estudo está localizada 220 km a jusante do reservatório de Yacyretá e 30 km a jusante da confluência dos Rios Paraná e Paraguai. Considerando que as águas destes rios permanecem sem se misturar no local de estudo, os possíveis efeitos do fechamento da barragem foram comparados em ambas as margens (direita e esquerda), durante as fases de águas altas e baixas de períodos hidrológicos de duração e magnitude semelhantes. As condições físico-químicas medidas na margem direita (águas do Rio Paraguai) foram similares em ambos os períodos (pré e pós-fechamento), observando-se aumento nos valores da condutividade, pH e concentração de ortofosfato na margem esquerda (águas do alto Rio Paraná e do reservatório de Yacyretá) no período pós-fechamento. Alterações na densidade e composição da comunidade fitoplanctônica foram observadas somente em amostras coletadas de águas provenientes do reservatório (margem esquerda). As densidades de Chlorophyceae (Chloromonas acidophila, Chlamydomonas leptobasis, Choricystis minor, Chlorella vulgaris, Scenedesmus ecornis, Monoraphidium minutum, M. contortum e M. pusillum) e Cryptophyceae (Rhodomonas minuta, Cryptomonas marssonii e C. ovata) incrementaram-se, no entanto houve diminuição das densidades de Cyanophyceae (Cylindrospermopsis raciborskii, Raphidiopsis mediterranea e Planktolyngbya subtilis) e Bacillariophyceae (Aulacoseira granulata e suas bioformas), se comparadas a estudos prévios desenvolvidos nesta margem. O fitoplâncton coletado nos períodos pré e pós-fechamento na margem direita não mostrou diferencas por se originar no Rio Paraguai, que permanece relativamente pouco afetado pelas atividades humanas.