Role of vegetation (Typha latifolia) on nutrient removal in a horizontal subsurface-flow constructed wetland treating UASB reactor-trickling filter effluent.

The main objective of the work is to characterize the role of plants in a constructed wetland in the removal of nitrogen (N) and phosphorus (P). The experiments were carried out in a full-scale system in the city of Belo Horizonte, Brazil, with two parallel horizontal subsurface-flow constructed wetland units (one planted with Typha latifolia and one unplanted) treating the effluent from a system composed of an upflow anaerobic sludge blanket reactor and a trickling filter (TF). Each wetland unit received a mean flow of approximately 8.5 m³ d⁻¹ (population equivalent around 60 inhabitants each), with a surface hydraulic loading rate 0.12 m³m⁻²d⁻¹. The experiments were conducted from September 2011 to July 2013. Mean effluent concentrations from the wetlands were: (a) planted unit total nitrogen (TN) 22 mg L⁻¹, ammonia-N 19 mg L⁻¹, nitrite-N 0.10 mg L⁻¹, nitrate-N 0.25 mg L⁻¹, P-total 1.31 mg L⁻¹; and (b) unplanted unit TN 24 mg L⁻¹, ammonia-N 20 mg L⁻¹, nitrite-N 0.54 mg mL⁻¹, nitrate-N 0.15 mg L⁻¹, P-total 1.31 mg L⁻¹. The aerial part of the plant contained mean values of 24.1 gN (kg dry matter)⁻¹ and 4.4 gP (kg dry matter)⁻¹, and the plant root zone was composed of 16.5 gN (kg dry matter)⁻¹ and 4.1 gP (kg dry matter)⁻¹. The mean extraction of N by the plant biomass was 726 kgN ha⁻¹y⁻¹, corresponding to 17% of the N load removed. For P, the extraction by the plant biomass was 105 kgP ha⁻¹y⁻¹, corresponding to 9% of the P load removed. These results reinforce the reports that N and P removal due to plant uptake is a minor mechanism in horizontal subsurface-flow constructed wetlands operating under similar loading rates, typical for polishing of sanitary effluent.

Functional evaluation of central cholinergic circuits in patients with Parkinson's disease and REM sleep behavior disorder: a TMS study.

Central cholinergic dysfunction has been reported in patients with Parkinson's disease (PD) and hallucinations by evaluating short latency afferent inhibition (SAI), a transcranial magnetic stimulation protocol which gives the possibility to test an inhibitory cholinergic circuit in the human brain. REM sleep behavior disorder (RBD) was also found to be associated with cognitive impairment in PD patients. The objective of the study was to assess the cholinergic function, as measured by SAI, in PD patients with RBD (PD-RBD) and PD patients without RBD (PD-nRBD). We applied the SAI technique in 10 PD-RBD patients, in 13 PD-nRBD patients and in 15 age-matched normal controls. All PD patients and control subjects also underwent a comprehensive battery of neuropsychological tests. Mean SAI was significantly reduced in PD-RBD patients when compared with PD-nRBD patients and controls. Neuropsychological examination showed mild cognitive impairment in 9 out of the 10 PD-RBD patients, and in 5 out of the 13 PD-nRBD. SAI values correlated positively with neuropsychological tests measuring episodic verbal memory, executive functions, visuoconstructional and visuoperceptual abilities. Similar to that previously reported in the idiopathic form of RBD, SAI abnormalities suggest a cholinergic dysfunction in PD patients who develop cognitive impairment, and present findings indicate that RBD is an important determinant of MCI in PD.

Performance and behaviour of planted and unplanted units of a horizontal subsurface flow constructed wetland system treating municipal effluent from a UASB reactor.

A system composed of two horizontal subsurface flow constructed wetlands operating in parallel was evaluated for the post-treatment of UASB (upflow anaerobic sludge blanket) reactor effluent, for a population equivalent of 50 inhabitants per unit. One unit was planted with cattail (Typha latifolia) and the other was unplanted. The study was undertaken over a period of 4 years, comprising monitoring of influent and effluent constituents together with a full characterization of the behaviour of the units (tracer studies, mathematical modelling of chemical oxygen demand (COD) decay, characterization of solids in the filter medium). The mean value of the surface hydraulic load was 0.11 m(3)m(-2)d(-1), and the theoretical hydraulic retention time was 1.1 d in each unit. Using tracer tests with (82)Br, dispersion number (d) values of 0.084 and 0.079 for the planted and unplanted units were obtained, indicating low to moderate dispersion. The final effluent had excellent quality in terms of organic matter and suspended solids, but the system showed low capacity for nitrogen removal. Four-year mean effluent concentration values from the planted and unplanted units were, respectively: biochemical oxygen demand (BOD(5)): 25 and 23 mg L(-1); COD: 50 and 55 mg L(-1); total suspended solids (TSS): 9 and 9 mg L(-1); N-ammonia: 27 and 28 mg L(-1). The COD decay coefficient K for the traditional plug-flow model was 0.81 and 0.84 d(-1) for the planted and unplanted units. Around 80% of the total solids present in the filter medium were inorganic, and most of them were present in the interstices rather than attached to the support medium. As an overall conclusion, horizontal subsurface flow wetlands can be a very suitable post-treatment method for municipal effluents from anaerobic reactors.

Assessment of leaching risk of trace metals, PAHs and PCBs from a brownfield located in a flooding zone.

An old industrial site (brownfield) located south of Paris in a flooding plain and containing demolition disposal as well as a burning zone for metal recovery is being regenerated to satisfy local need for public green space. The main objective of the described study was therefore to assess the risk of remobilisation of trace metals, PAH and PCB present. The research focused on vertical migration due to rainfall (non-saturated flow) and to river flooding (saturated flow). To assess the remobilisation risk, representative soil profiles were reconstituted and eluted in columns with artificial rain and filtered river water for 6 weeks with an equivalent of 25 mm d-1. Soil analysis showed that both zones are highly contaminated, exceeding the French environmental standards. Though the superficial metal content was much higher in the burning zone with levels of g kg-1 than that in the demolition zone, most metals showed higher levels in the eluents of the latter. The level of dissolved Zn in the burning zone eluent was 30 µg L-1, while in the demolition zone, it was 300 µg L-1, 40 times the admissible level. Zn was thereby correlated to aromaticity parameter HIX, indicating a link with organic matter transformation. The Cu was only significantly released under saturated condition (up to 80 µg L-1) in the demolition soil, indicating as implicated mechanism manganese and iron oxide reduction rather than organic matter transformation. Despite the high PAH and PCB soil contents, these pollutants were not released. The total PAH content in the effluent was 30 ng L-1 in average and did not significantly differ between the two zones and the types of hydrology. Only Zn and Cu issued from demolition zone presented an eco-toxicological risk. Crossed statistical analysis of the results showed that the role of the soil type is preponderant in the pollutant release and that temporary flooding condition would induce a lower impact on the groundwater quality than an equivalent amount of fallen rain. Though the burning site was far more contaminated in the upper soil than the demolition zone, it presented little risk compared to the demolition zone, more profound and more permeable. The latter showed therefore significative trace metal release, up to 2.1 kg ha-1 year-1 for zinc, doubling the local atmospheric deposition.

Cognitive function and cholinergic transmission in patients with subcortical vascular dementia and microbleeds: a TMS study.

There has been little investigation on the association between cognitive impairment and the microbleeds (MBs) frequently seen in subcortical vascular dementia (SVaD). One possible mechanism of cognitive decline in individuals with SVaD could be disruption of cholinergic fibers by vascular lesions. Central cholinergic circuits in human brain can be tested non-invasively by means of a transcranial magnetic stimulation (TMS) protocol named short latency afferent inhibition (SAI) of motor cortex. In the present study, we used this test in SvaD patients with and without MBs. SAI was evaluated in 13 SVaD patients with MBs (MB-positive group) and the data were compared with those from a group of 15 SVaD patients without MBs (MB-negative group) and with those from 20 healthy subjects. Moreover, we studied covariation of individual SAI values with the Mini-Mental State Examination (MMSE) total score and subscores. SAI was significantly reduced in the MB-positive group when compared with the MB-negative group and the control subjects. Total MMSE score, "attention and calculation" and "orientation" subscores were significantly lower in the MB-positive group than in the MB-negative group; SAI showed a positive correlation with total MMSE score. Adjustment for age, gender, education, presence of lacunae, severe white matter hyperintensities or severe periventricular hyperintensities did not affect these findings. This study provides novel physiological evidence that MBs have an impact on central cholinergic function that is independent of the extent of associated white matter changes and ischaemic stroke. This finding shows that TMS have potential diagnostic and therapeutic implications. TMS studies may help in evaluating the causes of cognitive impairment in cerebrovascular diseases.

Impact of urbanisation (trends) on runoff behaviour of Pampulha watersheds (Brazil).

The paper presents an analysis of runoff behaviour of four urban catchments between the municipalities of Belo Horizonte and Contagem in Brazil, linked to their land use. Two years of online measurement of flow data, combined with spatial analysis, was linked through runoff modelisation with EPA SWMM. The coefficients of Nash obtained varying between 0.75 and 0.87 demonstrated an adequate modelling approach. A 1-year rain series was applied to evaluate the runoff behaviour of actual land cover and that of 2002. The peak flows normalised to watershed surfaces revealed as the most urbanised (85%) watershed Ressaca with 178 L/ha/s, three times more runoff intensive than the least urbanised (41%) Mergulhão with 67 L/ha/s. Statistical analysis of land cover data and modelling results on watershed and sub-watershed level showed main correlations between hydrological parameters such as peak flow, average event flow and restitution time, but also between land cover and runoff coefficient. This approach gave a linear relation between runoff and green surface, with a runoff coefficient of 0.86 for fully urbanised zone and 0.43 for full "green" cover. Prospective simulation with actual urbanisation rates varying from 4 to 34 ha/year suggested an increase between 6 and 18% of the flows and a possible end of urbanisation within the next two to three decades. These findings should contribute to a better understanding of hydrological impact of Belo Horizonte urbanisation and to the restauration of its Lake Pampulha.

Current and emerging treatment options for spinal cord ischemia.

Spinal cord infarction (SCI) is a rare but disabling disorder caused by a wide spectrum of conditions. Given the lack of randomized-controlled trials, contemporary treatment concepts are adapted from guidelines for cerebral ischemia, atherosclerotic vascular disease, and acute traumatic spinal cord injury. In addition, patients with SCI are at risk for several potentially life-threatening but preventable systemic and neurologic complications. Notably, there is emerging evidence from preclinical studies for the use of neuroprotection in acute ischemic injury of the spinal cord. In this review, we discuss the current state of the art for the therapy and prevention of SCI and highlight potential emerging treatment concepts awaiting translational adoption.

Effect of substrate depth and rain-event history on the pollutant abatement of green roofs.

This study compares the effectiveness of two different thickness of green roof substrate with respect to nutrient and heavy metal retention and release. To understand and evaluate the long term behaviour of green roofs, substrate columns with the same structure and composition as the green roofs, were exposed in laboratory to artificial rain. The roofs act as a sink for C, N, P, zinc and copper for small rain events if the previous period was principally dry. Otherwise the roofs may behave as a source of pollutants, principally for carbon and phosphorus. Both field and column studies showed an important retention for Zn and Cu. The column showed, however, lower SS, DOC and metal concentrations in the percolate than could be observed in the field even if corrected for run-off. This is most probably due to the difference in exposition history and weathering processes.

Avaliação do desempenho de sistemas alagados construídos de escoamento horizontal subsuperficial tratando efluente de reator UASB, com base em quatro anos de monitoramento / Performance evaluation of horizontal subsurface flow constructed wetlands in the treatment of UASB reactor effluent, based on four years of monitoring

RESUMO Um sistema composto por um reator anaeróbio tipo upflow anaerobic sludge blanket (UASB), seguido de um sistema de alagados construídos (SAC) de escoamento horizontal subsuperficial compreendendo duas unidades em paralelo (50 habitantes cada), foi avaliado para o tratamento de águas residuárias geradas na cidade de Belo Horizonte, Minas Gerais, Brasil. Uma unidade foi plantada com Typha latifolia e a outra não foi vegetada. Amostras semanais do efluente do reator UASB e do efluente das unidades do SAC foram avaliadas por um período de quatro anos de operação do sistema. Nas taxas de aplicação praticadas (média de 0,11 m3.m-2.d-1), o efluente final apresentou excelente qualidade em termos de matéria orgânica e sólidos suspensos, mas baixa capacidade de remoção de nitrogênio. Os valores médios de concentração no efluente das unidades plantadas e não plantadas foram, respectivamente, demanda bioquímica de oxigênio: 25 e 23 mg.L-1; demanda química de oxigênio: 50 e 55 mg.L-1; sólidos suspensos totais: 10 e 8 mg.L-1; nitrogênio Kjeldahl total: 30 e 31 mg.L-1; e nitrogênio amoniacal: 27 e 28 mg.L-1. Não se observou diferença significativa entre as concentrações efluentes das unidades plantada e não plantada para a maioria dos constituintes investigados.

ABSTRACT A system composed of an upflow anaerobic sludge blanket (UASB) reactor followed by two horizontal subsurface flow wetlands (50 inhabitants each) constructed in parallel was evaluated for the treatment of municipal wastewater generated in the city of Belo Horizonte, Minas Gerais, Brazil. One unit was planted with Typha latifolia, and the other one was not planted. Weekly samples of the effluent from the UASB reactor and the effluent from both wetland units were evaluated for a period of four years of the system's operation. With the applied loads (average of 0.11 m3.m-2.d-1), the final effluent showed excellent quality in terms of organic matter and suspended solids, but it showed low capacity for nitrogen removal. Mean concentration values in the effluent from the planted and unplanted units were, respectively, biochemical oxygen demand: 25 and 23 mg.L-1; chemical oxygen demand: 50 and 55 mg.L-1; total suspended solids: 10 and 8 mg.L-1; total Kjeldahl nitrogen: 30 and 31 mg.L-1; and N-ammonia: 27 and 28 mg.L-1. There was no significant difference between the effluent concentrations from the planted and unplanted units for most of the evaluated constituents.

Functional brain reorganization after spinal cord injury: systematic review of animal and human studies.

Plastic changes of neural circuits occur after spinal cord injury (SCI) at various level of the central nervous system. In this review we will focus on delineating the pathophysiological mechanisms of the brain plasticity changes following SCI, based on the existing neuroimaging and neurophysiological evidence in experimental models and humans. In animal experiments, reorganization of the sensory topography as well as of the topographical map of primary motor and premotor cortices have been reported in several studies. Brain imaging revealed that cortical representation in response to spared forelimb stimulation early enlarges and invades adjacent sensory-deprived hind limb territory. Electrophysiological studies demonstrated that the deafferentation due to SCI can immediately change the state of large cortical networks within 1h, and that these changes play a critical role in the functional reorganization after SCI. In humans neuroimaging also showed shifts of functional motor and sensory cortical representations that relate to the severity of SCI. In patients with cervical SCI, cortical forearm motor representations, as assessed by means of transcranial magnetic stimulation, may reorganize towards the intrinsic hand motor representation to maximize output to muscles of the impaired forearm. Excessive or aberrant reorganisation of cerebral cortex may also have pathological consequences, such as phantom sensations or neuropathic pain. Integrated neuroimaging and neurophysiological approaches may also lead to the development of new therapeutic strategies, which have the potential of enhancing sensorimotor recovery in patients with SCI.

Cortical excitability changes in patients with sleep-wake disturbances after traumatic brain injury.

Although chronic sleepiness is common after head trauma, the cause remains unclear. Transcranial magnetic stimulation (TMS) represents a useful complementary approach in the study of sleep pathophysiology. We aimed to determine in this study whether post-traumatic sleep-wake disturbances (SWD) are associated with changes in excitability of the cerebral cortex. TMS was performed 3 months after mild to moderate traumatic brain injury (TBI) in 11 patients with subjective excessive daytime sleepiness (EDS; defined by the Epworth Sleepiness Scale ≥10), 12 patients with objective EDS (as defined by mean sleep latency <5 on multiple sleep latency tests), 11 patients with fatigue (defined by daytime tiredness without signs of subjective or objective EDS), 10 patients with post-traumatic hypersomnia "sensu strictu," and 14 control subjects. Measures of cortical excitability included central motor conduction time, resting motor threshold (RMT), short-latency intracortical inhibition (SICI), and intracortical facilitation to paired-TMS. RMT was higher and SICI was more pronounced in the patients with objective EDS than in the control subjects. In the other patients all TMS parameters did not differ significantly from the controls. Similarly to that reported in patients with narcolepsy, the cortical hypoexcitability may reflect the deficiency of the excitatory hypocretin/orexin-neurotransmitter system. These observations may provide new insights into the causes of chronic sleepiness in patients with TBI. A better understanding of the pathophysiology of post-traumatic SWD may also lead to better therapeutic strategies in these patients.

Modelagem da Lagoa da Pampulha: uma ferramenta para avaliar o impacto da bacia hidrográfica na dinâmica do fitoplâncton / Modelling Lake Pampulha: a tool for assessing the catchment area impacts on the phytoplankton dynamics

RESUMO No processo de urbanização, o aumento na proporção de superfícies impermeabilizadas e as mudanças no uso do solo são responsáveis por maiores volumes e velocidades do escoamento superficial, refletindo em uma maior capacidade de arraste e em um maior aporte de nutrientes nos corpos d'água receptores. O objetivo deste trabalho foi implementar uma ferramenta matemática capaz de reproduzir o impacto de mudanças na bacia hidrográfica sobre a dinâmica do fitoplâncton em um lago urbano. Neste artigo são apresentados o desenvolvimento e os resultados de um modelo integrado constituído de um modelo hidrológico, para simular vazões escoadas em uma bacia hidrográfica, e de um modelo hidrodinâmico e ecológico, para simular a biomassa fitoplanctônica em um corpo d'água urbano. A Lagoa da Pampulha (Belo Horizonte, Minas Gerais), escolhida como estudo de caso, foi intensamente monitorada, assim como sua bacia de drenagem, entre outubro de 2011 e junho de 2013. Os dados obtidos foram utilizados para calibrar e validar ambos os modelos. Os resultados obtidos com o modelo hidrológico mostraram-se coerentes com as medidas realizadas em campo (o coeficiente de Nash variou entre 0,70 e 0,88). O modelo da lagoa representou corretamente a evolução da comunidade fitoplanctônica (erro médio absoluto normalizado: 0,25-0,42 e o coeficiente de Pearson: 0,82-0,89; p<0,0001). O monitoramento e a modelagem da lagoa mostraram que a proliferação de cianobactérias é bastante perturbada pelas desestratificações térmicas que ocorrem na lagoa em virtude de eventos meteorológicos. A ferramenta de simulação desenvolvida possui potencial para avaliar diferentes cenários de mudança das condições climáticas e das características da bacia, podendo auxiliar na gestão dos corpos d'água situados em meio urbano.

ABSTRACT In urban areas the increasing imperviousness is responsible for rising runoff volume and speed, leading to a greater capacity to load nutrients and pollutants into reservoirs. In order to study the impacts of catchment changes on the phytoplankton dynamics in urban lakes, a modelling approach in which a hydrological model is connected to an ecological lake model is proposed for Lake Pampulha (Brazil). In this paper we present the methodology used to link both models. Lake Pampulha and its catchment area were intensively monitored between October 2011 and June 2013 in order to provide data for the calibration and validation of both models. The results of the hydrologic model showed good agreement with the in situ measurements, and the Nash coefficient ranged from 0.70 to 0.88. The lake ecological model have successfully represented the cyanobacteria dynamics (normalized mean average error: 0.25-0.42, Pearson coefficient: 0.82-0.89, p<0.0001). Monitoring and modelling showed that cyanobacteria blooms are quite disturbed by water column mixing caused by rain events. The mathematical tool developed here can be used to assess different scenarios of climate changes or catchment area changes and can be very helpful for the management of urban water resources.