Evaluación numérico-experimental del comportamiento histérico del coeficiente de rugosidad de los macrófitos

La problemática asociada al crecimiento masivo de macrófitos en el Bajo Ebro ha llevado a autoridades y gestores a examinar la posibilidad de paliar los efectos negativos que producen sobre el sistema hídrico, y los usos del agua, mediante la realización de avenidas controladas periódicas que provoquen su remoción. El presente trabajo tiene como objetivo principal evaluar el comportamiento hidráulico de los macrófitos mediante simulación numérica (modelo Iber) y su comparación con datos de campo, con el fin de explorar las mejores opciones posibles para diseñar avenidas controladas más eficaces. Para ello se han empleado diferentes relaciones entre el coeficiente de rugosidad y la altura de agua bajo tres enfoques distintos (constante, variable y variable con histéresis) a fin de calibrar el modelo numérico con los datos de campo. Se ha podido observar que el mejor ajuste se produce cuando dichas curvas son de tipo variable con histéresis (diferente rama de subida que de bajada)

Numerical-experimental assessment of the hysterical behaviour of the macrophytes roughness coefficient

[EN] The associated problems with the massive growth of macrophytes in the Lower Ebro, has led authorities and managers to explore the possibilities to minimize their negative effects on the water ecosystem and associated water uses by removing them by means of controlled floods. The main goal of the present work is to evaluate the hydraulic behaviour of the macrophytes through numerical simulation (Iber model) and its comparison with field data, in order to design the most efficient flushing flows. For this purpose, roughness coefficient – water depth relations (constant, variable and variable with hysteresis) were used to calibrate the numerical model with field data. It was observed that the best fit occurred the variable type with hysteresis curves (different ascent and descent branches) were used.[ES] La problemática asociada al crecimiento masivo de macrófitos en el Bajo Ebro ha llevado a autoridades y gestores a examinar la posibilidad de paliar los efectos negativos que producen sobre el sistema hídrico, y los usos del agua, mediante la realización de avenidas controladas periódicas que provoquen su remoción. El presente trabajo tiene como objetivo principal evaluar el comportamiento hidráulico de los macrófitos mediante simulación numérica (modelo Iber) y su comparación con datos de campo, con el fin de explorar las mejores opciones posibles para diseñar avenidas controladas más eficaces. Para ello se han empleado diferentes relaciones entre el coeficiente de rugosidad y la altura de agua bajo tres enfoques distintos (constante, variable y variable con histéresis) a fin de calibrar el modelo numérico con los datos de campo. Se ha podido observar que el mejor ajuste se produce cuando dichas curvas son de tipo variable con histéresis (diferente rama de subida que de bajada).Los autores agradecen a ENDESA GENERACIÓN (UPH Ebro-Pirineos) el acceso a los datos de las avenidas controladas, a ENDESA S.A. (Cambio Climático, Biodiversidad, I+D+i ambiental y Recursos Hídricos) la financiación de la primera campaña de campo y los trabajos de modelización numérica (Instituto Flumen, 2016), al Grupo Especial de Actividades Subacuáticas de la Guardia Civil su colaboración en la primera campaña de campo y al Grupo de Investigación de Dinámica Fluvial RIUS (Universidad de Lleida) los datos batimétricos y topográficos facilitados.Sanz-Ramos, M.; Bladé, E.; Niñerola, D.; Palau-Ibars, A. (2018). Evaluación numérico-experimental del comportamiento histérico del coeficiente de rugosidad de los macrófitos. Ingeniería del Agua. 22(3):109-124. doi:10.4995/ia.2018.8880SWORD109124223Arcement, G. J. J. y Schneider, V. R., 1989. Guide for Selecting Manning's Roughness Coefficients for Natural Channels and Floodplains. USGS Water-supply Paper 2339.Anderson, L. W. J. 2003. A review of aquatic weed biology and management research conducted by the United Status Department of Agriculture - Agricultural Research Service. Pest Management Science, 59, 801-813. https://doi.org/10.1002/ps.725Batalla, R. J., Vericat, D. 2009. Hydrological and sediment transport dynamics of flushing flows: implications for management in large Mediterranean rivers. River Research and Applications, 25, 297-314. https://doi.org/10.1002/rra.1160Barnes, H. H., 1987. Roughness Characteristics of Natural Channels. USGS.Berger, C., Wells, S. 2008. Modeling the Effects of Macrophytes on Hydrodynamics. J. Environ. Eng., 134(9), 778-788. https://doi.org/10.1061/(ASCE)0733-9372(2008)134:9(778)Bladé, E., Cea. L., Corestein, G., Escolano, E., Puertas, J., Vázquez-Cendón, E., Dolz, J., Coll, A. 2014a. Iber: herramienta de simulación numérica del flujo en ríos. Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería. CIMNE (Universitat Politècnica de Catalunya), 30(1), 1-10.Bladé, E., Cea, L., Corestien, G. 2014b. Modelización numérica de inundaciones. Ingeniería del Agua, 18(1), 71-82. https://doi.org/10.4995/ia.2014.3144Carr, G. M., Duthie, H. C., Taylor, W. D. 1997. Models of aquatic plant productivity: a review of the factors that influence growth. Aquatic Botany, 59, 195-215. https://doi.org/10.1016/S0304-3770(97)00071-5Cirujano, S., Meco, A., Cezón, K. 2011. Flora acuática: Macrófitos. Jornada de presentación del Tesauro Taxonómico para la clasificación del estado ecológico de las masas de agua continentales, TAXAGUA. Ministerio de Medio Ambiente y Medio Rural y Marino, Madrid, España.CHE. 2008. Vuelo multiespectral para la caracterización de macrófitos. Confederación Hidrográfica del Ebro, expediente 173/08-SNS.CHE. 2010. Asistencia técnica para el control de macrófitos: Mejora de la gestión de los embalses del Bajo Ebro. Entidades colaboradoras: URS, ENDESA, Universidad de Girona y Universitat de Lleida. Zaragoza. 145 pp.CHE. 2015. Memoria Anual 2015 de la Confederación Hidrográfica del Ebro. Ministerio de Agricultura. Alimentación y Medio Ambiente. Centro de Publicaciones (NIPO: 284160028).Dawson, F. H., Robinson, W. N. 1984. Submerged macrophytes and the hydraulic roughness of a lowland chalkstream. Verh. Internat. Verein. Limnol., 22, 1944-1948. https://doi.org/10.1080/03680770.1983.11897598ENDESA. 2016. Estudi granulomètric del tram aigües avall de la Central Hidroelèctrica de Flix. Informe técnico inédito (Eccus, S.L.). Febrero 2016, Lleida, España.Fathi-Moghadam, M., Kashefipour, M., Ebrahimi, N., Emamgholizadeh, S. 2011. Physical and Numerical Modeling of Submerged Vegetation Roughness in Rivers and Flood Plains. Journal of Hydrologic Engineering, 16(11), 858-864. https://doi.org/10.1061/(ASCE)HE.1943-5584.0000381Fathi-Moghadam, M., Drikvandi, K. 2012. Manning Roughness Coefficient for Rivers and Flood Plains with Non-Submerged Vegetation. International Journal of Hydraulic Engineering, 1(1), 1-4. https://doi.org/10.5923/j.ijhe.20120101.01Green, J. C. 2005a. Further comment on drag and reconfiguration of macrophytes. Freshwater Biology, 50, 2162-2166. https://doi.org/10.1111/j.1365-2427.2005.01470.xGreen, J. C. 2005b. Modelling flow resistance in vegetated streams: review and development of new theory. Hydrological Processes, 19, 1245-1259. https://doi.org/10.1002/hyp.5564Green, J. C. 2006. Effect of macrophyte spatial variability on channel resistance. Advances in Water Resources, 29(3), 426-438. https://doi.org/10.1016/j.advwatres.2005.05.010Hui, E., Hu, X. 2010. A study of drag coefficient related with vegetation based on the flume experiment. Journal of Hydrodynamics. 22(3), 329-337. https://doi.org/10.1016/S1001-6058(09)60062-7Instituto Flumen. 2016. Estudio en Modelo numérico de la capacidad erosiva del río Ebro en el tramo Flix-Ascó. Informe técnico inédito (Insituto Flume). Abril 2016, Barcelona, España.Järvelä, J. 2002. Flow resistance of flexible and stiff vegetation: a flume study with natural plants. Journal of Hydrology, 269(1-2) 44-54. https://doi.org/10.1016/S0022-1694(02)00193-2Järvelä, J. 2005. Effect of submerged flexible vegetation on flow structure and resistance. Journal of Hydrology, 307(1-4), 233-241. https://doi.org/10.1016/j.jhydrol.2004.10.013Montesinos, S., Fernández, L. 2009. Determinación de macrófitos en el río Ebro entre Flix y Mora d'Ebre. Teledetección. Agua y Desarrollo Sostenible. Actas del XIII Congreso de Asociación Española de Teledetección, Calatayud, 137-140.Nikora, V., Larned, S., Nikora, N., Debnath, K., Cooper, G., Reid, M. 2008. Hydraulic Resistance due to Aquatic Vegetation in Small Streams: Field Study. Journal of Hydraulic Engineering. 134(9), 1326-1332 [Technical note]. https://doi.org/10.1061/(ASCE)0733-9429(2008)134:9(1326)Palau, A., Batalla, R.J., Rosico, E., Meseguer, A., Vericat, D. 2004. Management of water level and design of flushing floods for environmental river maintenance downstream of the Riba-Roja reservoir (lower Ebro River. NE Spain). HYDRO 2004-A New Era for Hydropower, Porto, Portugal. 18-20 October 2004.Prats, J., Dolz, J., Armengol, J. 2009. Variabilidad temporal en el comportamiento hidráulico del curso inferior del río Ebro. Ingeniería del Agua. 16(4), 259-272. https://doi.org/10.4995/ia.2009.2960Stephan, U., Gutknecht, D. 2002. Hydraulic resistance of submerged flexible vegetation. Journal of Hydrology, 269, 27-43. https://doi.org/10.1016/S0022-1694(02)00192-0Strickler, A. 1923. Beiträge zur Frage der Geschwindigkeitsformel und der Rauhigkeitszahl für Ströme. Kanäle und geschlossene Leitungen. Mitteilungen des Eidg. Amtes für Wasserwirtschaft. Bern. 1923.Tena, A., Ksiazek, L., Vericat, D., Batalla, R. J., 2013. Assessing the geomorphic effects of flushing flow in large regulated river. River Research and Applications 29: 876-890. https://doi.org/10.1002/rra.2572Vericat, D., Batalla, R. J. 2004. Efectos de las presas en la dinámica fluvial del curso bajo del río Ebro. Rev. C. & G., 18(1-2), 37-50.Wu, F., Shen, H., Chou, Y. 1999. Variation of Roughness Coefficients for Unsubmerged and Submerged Vegetation. J. Hydraul. Eng., 125(9), 934-942. https://doi.org/10.1061/(ASCE)0733-9429(1999)125:9(934

An overview of the management consulting firms of the Spanish company in China: company profile and success and failure factors

[EN] This article explores the vision of Management Consulting Firms (MCF) specialized in internationalization processes of Spanish companies in China. The main objective is to shed light on a process full of uncertainty as is international expansion into emerging markets on the point of view of the advisors of that process.First, it is analyzed whether there is a Spanish company profile that is internationalized toward China in terms of sector of activity, size and experience in international business. And second, with their client’s experiences, success and failure factors in the internationalization process are studied.To achieve those objectives in depth interviews were held with partners and managers of six Management Consulting Firms with Spanish clients in their portfolio.As a result it is concluded that the sectors where the Spanish company has invested are several, the size of the company is important to undertake an implementation process in China and its international experience as well.Eight key factors were found relevant to invest in China successfully.  Five factors are related with their resources (humans and financials) and the other three are related with their strategy. The main reasons of failure are also discussed.The article provides an outside perspective on the reasons why an internationalization process is successful and other fails.Niñerola, A.; Campa-Planas, F.; Hernández-Lara, A.; Sánchez-Rebull, M. (2016). An overview of the management consulting firms of the Spanish company in China: company profile and success and failure factors. Multidisciplinary Journal for Education, Social and Technological Sciences. 3(1):1-25. doi:10.4995/muse.2016.3711.SWORD1253

QuantiDOPA: A Quantification Software for Dopaminergic Neurotransmission SPECT

Quantification of neurotransmission Single-Photon Emission Computed Tomography (SPECT) studies of the dopaminergic system can be used to track, stage and facilitate early diagnosis of the disease. The aim of this study was to implement QuantiDOPA, a semi-automatic quantification software of application in clinical routine to reconstruct and quantify neurotransmission SPECT studies using radioligands which bind the dopamine transporter (DAT). To this end, a workflow oriented framework for the biomedical imaging (GIMIAS) was employed. QuantiDOPA allows the user to perform a semiautomatic quantification of striatal uptake by following three stages: reconstruction, normalization and quantification. QuantiDOPA is a useful tool for semi-automatic quantification inDAT SPECT imaging and it has revealed simple and flexibl

Short Communication Analysis, Toxicity and Biodegradation of Organic Pollutants in Groundwater from Contaminated Land

Headspace (HS) gas chromatography with flame ionisation detection (HS-GC-FID) and purge and trap (P&T) gas chromatography-mass spectrometry (P&T-GC-MS) were used for the determination of methyl-tert-butyl ether (MTBE) and benzene, toluene, and xylenes (BTEX) in groundwater. In this work, we present the first data on the levels of MTBE and BTEX in different groundwater wells in the area of Catalonia (northeast Spain). This monitoring campaign corresponded to 28 groundwater wells that were located near petrol service stations, oil refinery storage tanks, and/or chemical industry at different locations of Catalonia during the period of 1998/1999. The levels of MTBE detected varied between 4-300 µg/l, but two sites had MTBE levels up to 3 and 13 mg/l. In many cases, the BTEX levels were below 1 µg/l, whereas 7 sites had levels varying from 19 µg/l up to 3 mg/l. Most of them were related to leakage from underground tanks in petrol service stations, while the remaining three corresponded respectively to chemical industrial pollution of undetermined origin and to a leak from high-ground petrol tanks in petrochemical refinery factories. The aquifers involved were constituted by detritus coarse materials, sands, and conglomerates. Piezometric levels were roughly comprised between 3 and 40 m, and permeability (K) and transmissivity (T) values were estimated from field measurements. The MTBE/BTEX ratio was also calculated and reached values up to 250. These values were expected, since if we consider that spilled oxygenated gasoline is the source of well contamination and based on solubility considerations alone, the MTBE source concentrations would be about 200 times higher than any BTEX compounds

Cerebral amyloid‐β load is associated with neurodegeneration and gliosis: Mediation by p‐tau and interactions with risk factors early in the Alzheimer's continuum

Introduction: The association between cerebral amyloid‐β accumulation and downstream CSF biomarkers is not fully understood, particularly in asymptomatic stages. / Methods: In 318 cognitively unimpaired participants, we assessed the association between amyloid‐β PET (Centiloid), and cerebrospinal fluid (CSF) biomarkers of several pathophysiological pathways. Interactions by Alzheimer's disease risk factors (age, sex and APOE‐ε4), and the mediation effect of tau and neurodegeneration were also investigated. / Results: Centiloids were positively associated with CSF biomarkers of tau pathology (p‐tau), neurodegeneration (t‐tau, NfL), synaptic dysfunction (neurogranin) and neuroinflammation (YKL‐40, GFAP, sTREM2), presenting interactions with age (p‐tau, t‐tau, neurogranin) and sex (sTREM2, NfL). Most of these associations were mediated by p‐tau, except for NfL. The interaction between sex and amyloid‐β on sTREM2 and NfL was also tau‐independent. / Discussion: Early amyloid‐β accumulation has a tau‐independent effect on neurodegeneration and a tau‐dependent effect on neuroinflammation. Besides, sex has a modifier effect on these associations independent of tau

Differential effects of sleep on brain structure and metabolism at the preclinical stages of AD

INTRODUCTION: Poor sleep quality is associated with cognitive outcomes in Alzheimer's disease (AD). We analyzed the associations between self-reported sleep quality and brain structure and function in cognitively unimpaired (CU) individuals. METHODS: CU adults (N = 339) underwent structural magnetic resonance imaging, lumbar puncture, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire. A subset (N = 295) performed [18F] fluorodeoxyglucose positron emission tomography scans. Voxel-wise associations with gray matter volumes (GMv) and cerebral glucose metabolism (CMRGlu) were performed including interactions with cerebrospinal fluid (CSF) AD biomarkers status. RESULTS: Poorer sleep quality was associated with lower GMv and CMRGlu in the orbitofrontal and cingulate cortices independently of AD pathology. Self-reported sleep quality interacted with altered core AD CSF biomarkers in brain areas known to be affected in preclinical AD stages. DISCUSSION: Poor sleep quality may impact brain structure and function independently from AD pathology. Alternatively, AD-related neurodegeneration in areas involved in sleep–wake regulation may induce or worsen sleep disturbances. Highlights Poor sleep impacts brain structure and function independent of Alzheimer's disease (AD) pathology. Poor sleep exacerbates brain changes observed in preclinical AD. Sleep is an appealing therapeutic strategy for preventing AD

Visual assessment of [¹⁸F]flutemetamol PET images can detect early amyloid pathology and grade its extent

PURPOSE: To investigate the sensitivity of visual read (VR) to detect early amyloid pathology and the overall utility of regional VR. METHODS: [¹⁸F]flutemetamol PET images of 497 subjects (ALFA+ N = 352; ADC N = 145) were included. Scans were visually assessed according to product guidelines, recording the number of positive regions (0-5) and a final negative/positive classification. Scans were quantified using the standard and regional Centiloid (CL) method. The agreement between VR-based classification and published CL-based cut-offs for early (CL = 12) and established (CL = 30) pathology was determined. An optimal CL cut-off maximizing Youden's index was derived. Global and regional CL quantification was compared to VR. Finally, 28 post-mortem cases from the [¹⁸F]flutemetamol phase III trial were included to assess the percentage agreement between VR and neuropathological classification of neuritic plaque density. RESULTS: VR showed excellent agreement against CL = 12 (κ = .89, 95.2%) and CL = 30 (κ = .88, 95.4%) cut-offs. ROC analysis resulted in an optimal CL = 17 cut-off against VR (sensitivity = 97.9%, specificity = 97.8%). Each additional positive VR region corresponded to a clear increase in global CL. Regional VR was also associated with regional CL quantification. Compared to mCERAD_{SOT}-based classification (i.e., any region mCERAD_{SOT} > 1.5), VR was in agreement in 89.3% of cases, with 13 true negatives, 12 true positives, and 3 false positives (FP). Regional sparse-to-moderate neuritic and substantial diffuse Aβ plaque was observed in all FP cases. Regional VR was also associated with regional plaque density. CONCLUSION: VR is an appropriate method for assessing early amyloid pathology and that grading the extent of visual amyloid positivity could present clinical value

Association of weight change with cerebrospinal fluid biomarkers and amyloid positron emission tomography in preclinical Alzheimer's disease

BACKGROUND: Recognizing clinical manifestations heralding the development of Alzheimer's disease (AD)-related cognitive impairment could improve the identification of individuals at higher risk of AD who may benefit from potential prevention strategies targeting preclinical population. We aim to characterize the association of body weight change with cognitive changes and AD biomarkers in cognitively unimpaired middle-aged adults. METHODS: This prospective cohort study included data from cognitively unimpaired adults from the ALFA study (n = 2743), a research platform focused on preclinical AD. Cognitive and anthropometric data were collected at baseline between April 2013 and November 2014. Between October 2016 and February 2020, 450 participants were visited in the context of the nested ALFA+ study and underwent cerebrospinal fluid (CSF) extraction and acquisition of positron emission tomography images with [18F]flutemetamol (FTM-PET). From these, 408 (90.1%) were included in the present study. We used data from two visits (average interval 4.1 years) to compute rates of change in weight and cognitive performance. We tested associations between these variables and between weight change and categorical and continuous measures of CSF and neuroimaging AD biomarkers obtained at follow-up. We classified participants with CSF data according to the AT (amyloid, tau) system and assessed between-group differences in weight change. RESULTS: Weight loss predicted a higher likelihood of positive FTM-PET visual read (OR 1.27, 95% CI 1.00-1.61, p = 0.049), abnormal CSF p-tau levels (OR 1.50, 95% CI 1.19-1.89, p = 0.001), and an A+T+ profile (OR 1.64, 95% CI 1.25-2.20, p = 0.001) and was greater among participants with an A+T+ profile (p < 0.01) at follow-up. Weight change was positively associated with CSF Aβ42/40 ratio (β = 0.099, p = 0.032) and negatively associated with CSF p-tau (β = - 0.141, p = 0.005), t-tau (β = - 0.147 p = 0.004) and neurogranin levels (β = - 0.158, p = 0.002). In stratified analyses, weight loss was significantly associated with higher t-tau, p-tau, neurofilament light, and neurogranin, as well as faster cognitive decline in A+ participants only. CONCLUSIONS: Weight loss predicts AD CSF and PET biomarker results and may occur downstream to amyloid-β accumulation in preclinical AD, paralleling cognitive decline. Accordingly, it should be considered as an indicator of increased risk of AD-related cognitive impairment. TRIAL REGISTRATION: NCT01835717 , NCT02485730 , NCT02685969

Cardiac and placental mitochondrial characterization in a rabbit model of intrauterine growth restriction

BACKGROUND: Intrauterine growth restriction (IUGR) is associated with cardiovascular remodeling persisting into adulthood. Mitochondrial bioenergetics, essential for embryonic development and cardiovascular function, are regulated by nuclear effectors as sirtuins. A rabbit model of IUGR and cardiovascular remodeling was generated, in which heart mitochondrial alterations were observed by microscopic and transcriptomic analysis. We aimed to evaluate if such alterations are translated at a functional mitochondrial level to establish the etiopathology and potential therapeutic targets for this obstetric complication. METHODS: Hearts and placentas from 16 IUGR-offspring and 14 controls were included to characterize mitochondrial function. RESULTS: Enzymatic activities of complexes II, IV and II + III in IUGR-hearts (-11.96 ± 3.16%; -15.58 ± 5.32%; -14.73 ± 4.37%; p < 0.05) and II and II + III in IUGR-placentas (-17.22 ± 3.46%; p < 0.005 and -29.64 ± 4.43%; p < 0.001) significantly decreased. This was accompanied by a not significant reduction in CI-stimulated oxygen consumption and significantly decreased complex II SDHB subunit expression in placenta (-44.12 ± 5.88%; p < 0.001). Levels of mitochondrial content, Coenzyme Q and cellular ATP were conserved. Lipid peroxidation significantly decreased in IUGR-hearts (-39.02 ± 4.35%; p < 0.001), but not significantly increased in IUGR-placentas. Sirtuin3 protein expression significantly increased in IUGR-hearts (84.21 ± 31.58%; p < 0.05) despite conserved anti-oxidant SOD2 protein expression and activity in both tissues. CONCLUSIONS: IUGR is associated with cardiac and placental mitochondrial CII dysfunction. Up-regulated expression of Sirtuin3 may explain attenuation of cardiac oxidative damage and preserved ATP levels under CII deficiency. GENERAL SIGNIFICANCE: These findings may allow the design of dietary interventions to modulate Sirtuin3 expression and consequent regulation of mitochondrial imbalance associated with IUGR and derived cardiovascular remodeling