Light attenuation in photobioreactors and algal pigmentation under different growth conditions – model identification and complexity assessment

Microalgae are photosynthetic organisms, and thus one of the most important factors affecting their growth is light. Yet, effective design and operation of algal cultivation systems still lacks robust numerical tools. Here, a comprehensive and mathematically consistent simulation model is presented in the ASM-A framework that can accurately predict light availability and its impact on microalgae growth in photobioreactors (PBR). Three cylindrical column reactors, mimicking typical open pond reactors, with different diameters were used to conduct experiments where the light distribution was monitored inside the reactor. A batch experiment was conducted where the effect of nutrients and light availability on the pigmentation of the microalgae and light distribution was monitored. The effect of reactor size and cultivation conditions on the light distribution in PBRs was evaluated. Moreover, we assessed the effect of using different simulation model structures on the model prediction accuracy and uncertainty propagation. Results obtained show that light scattering can have a significant effect on light distribution in reactors with narrow diameter (typical to panel-type PBRs) and under cultivation conditions that promote low pigmentation or low biomass concentration. The light attenuation coefficient was estimated using the Lambert-Beer equation and it was compared to Schuster's law. The light attenuation was found to be dependent on biomass concentration and microalgae pigmentation. Using a discretized layer model to describe the light distribution in PBRs resulted in the most accurate prediction of microalgal growth and lowest uncertainty on model predictions. Due to model complexity a trade-off needs to be made between accuracy of the prediction ac simulation time.</p

The location of creative clusters in non-metropolitan areas: A methodological proposition

This article studies creative clusters outside metropolitan areas in Spain. Both the notion of cluster and that of creative activity tend to be associated by mainstream research with urban settings; thus, situating them in an non metropolitan or rural localities has required us to adapt the usual methodology to the scale and idiosyncrasies of a rural setting. Based on this new focus, we have been able to identify 761 municipalities that could host creative clusters within an initial area of study of 7367 non-metropolitan municipalities with fewer than 50,000 inhabitants. This methodology also has allowed us to measure intensity, internal composition, and localization, so that those of a more mature or advanced character, having a greater level of specialization and diversity, predominate in places close to metropolitan areas and the Mediterranean axis, whereas in the inner Spain, they are found in a lower proportion and in a more scattered and discontinuous manner. Activities belonging to the Functional Creations sector prevail over those from Communication and Patrimony in the configuration of the clusters, although there are differences in relative specialization according to their mature or advanced level. In addition, some of the most significant indicators of rural dynamism e population growth, human capital, unemployment, and economic activity e show much better behaviour in municipalities with creative clusters

Light attenuation in photobioreactors and algal pigmentation under different growth conditions – model identification and complexity assessment

Microalgae are photosynthetic organisms, and thus one of the most important factors affecting their growth is light. Yet, effective design and operation of algal cultivation systems still lacks robust numerical tools. Here, a comprehensive and mathematically consistent simulation model is presented in the ASM-A framework that can accurately predict light availability and its impact on microalgae growth in photobioreactors (PBR). Three cylindrical column reactors, mimicking typical open pond reactors, with different diameters were used to conduct experiments where the light distribution was monitored inside the reactor. A batch experiment was conducted where the effect of nutrients and light availability on the pigmentation of the microalgae and light distribution was monitored. The effect of reactor size and cultivation conditions on the light distribution in PBRs was evaluated. Moreover, we assessed the effect of using different simulation model structures on the model prediction accuracy and uncertainty propagation. Results obtained show that light scattering can have a significant effect on light distribution in reactors with narrow diameter (typical to panel-type PBRs) and under cultivation conditions that promote low pigmentation or low biomass concentration. The light attenuation coefficient was estimated using the Lambert-Beer equation and it was compared to Schuster's law. The light attenuation was found to be dependent on biomass concentration and microalgae pigmentation. Using a discretized layer model to describe the light distribution in PBRs resulted in the most accurate prediction of microalgal growth and lowest uncertainty on model predictions. Due to model complexity a trade-off needs to be made between accuracy of the prediction ac simulation time.</p

Functional changes induced by extrusion during cocoa alkalization

[EN] Polyphenols, a group of secondary metabolites, have well-known relevant effects on human health. During traditional alkalization, this content dramatically lowers. We aimed to evaluate an alternative alkalization method based on extrusion on cocoa functional characteristics. The results showed that the antioxidant capacity and total phenolic values increased as alkali concentration and temperature did, and these values doubled under less extreme conditions. Comparing the functional properties between extruded and traditionally produced powders revealed that catechin, epicatechin and dimers B1 and B2 contents were 43%, 33%, 54% and 34% lower in the extruded samples, respectively. However, this reduction was partially balanced by increased clovamide content up to 50%. Thus the total phenol content and antioxidant capacity of the extruded samples were statistically above those of the commercial one. Hence extrusion alkalization should be considered a new processing alternative to avoid markedly reducing functional properties.This work was funded by the Spanish Government and European Regional Development Fund (Project RTC-2016-5241-2).Valverde-Garcia, D.; Behrends, B.; Pérez-Esteve, É.; Kuhnert, N.; Barat Baviera, JM. (2020). Functional changes induced by extrusion during cocoa alkalization. Food Research International. 136:1-10. https://doi.org/10.1016/j.foodres.2020.10946911013

Cultural and creative ecosystems in medium-sized cities: Evolution in times of economic crisis and pandemic

This article seeks to forecast the short-and medium-term impacts of the coronavirus pandemic on the cultural and creative ecosystems of the 81 cities in Spain with between 50, 000 and 100, 000 inhabitants. Data on employment in nine sectors (per NACE Rev. 2) support the characterization of cultural ecosystems based on their dynamism, specialization, and propensity to form clusters (thanks to the co-location of certain sectors, meant to generate inter-sectoral spillovers and cross-sector synergies). The applied methodology consists of comparing these three attributes during and following the 2008 financial crisis. Then, any changes observed are interpreted in light of arguments from the COVID-19 literature, and from our own analysis, in order to assess the probability of recurrence (or nonrecurrence) during the current pandemic. Throughout this process, the metropolitan or non-metropolitan position of cities is taken into consideration. A first conclusion is that, as in the financial crisis, the behavior of ecosystems during the pandemic will be asymmetric. Secondly, metropolitan and non-metropolitan cities will maintain their distinctive sectoral specializations. Non-metropolitan cities appear to be more vulnerable for their strong connection to creative sectors most affected by the pandemic, although some can take advantage of good cultural supply and proximity to metropolitan centers. Metropolitan cities seem more secure, thanks to the higher presence of less vulnerable sectors (due to elevated and accelerating digitization). Nevertheless, most functional clusters were diminished during the financial crisis, and it seems unlikely that sectoral co-locations will re-emerge in a post-pandemic scenario as a business strategy, at least in the short term. Beyond these forecasts, we recommend dealing with certain structural failures of these ecosystems, especially the vulnerability and precariousness of most cultural and creative companies and workers

Cultural dynamism and business vitality in medium-sized cities—evidence and proposals for sustainable development

This work uses tools recently designed to conduct analyses and proposals around the cultural development of medium-sized cities. The Cultural and Creative Cities Monitor model, or CCCM, is first applied to the 81 cities in Spain with between 50, 000 and 100, 000 inhabitants. We also refer to the UNESCO Culture/2030 Indicators, specifically indicator 8 (Cultural companies), to in-vestigate whether cultural dynamism is related to business vitality in those cities. Our observation of the 29 CCCM indicators and the C3 index, which synthesizes cultural performance, is explained, and these data are complemented with cultural business data (on assets, benefits, and jobs) from a sample of 13, 204 firms. The C3 index values reveal significant differences in the cultural and creative performance of the selected cities according to their location (metropolitan or non-metropolitan) and their administrative rank. Moreover, when comparing the C3 index with the indicators on business activity, evidence indicates a clear positive relationship between cultural dynamism and firm vitality. These results support the contribution of culture to the sustainable development of me-dium-sized Spanish cities and further establish the suitability of the tools used to assist cities in designing appropriate cultural policies

Socioeconomic inequalities in disability in Europe: contribution of behavioral, work-related and living conditions

BACKGROUND: Previous studies have shown the existence of social inequalities in disability in many European countries. However, it is not clear what factors are associated with these inequalities. The aim of this study was to assess the contribution of behavioral factors, work-related factors and living conditions to educational inequalities in disability. METHODS: We pooled data from the seventh wave of the European Social Survey (2014) which included self-reported disability measured with the Global Activity Limitations Indicator for 19 European countries. We used multivariate logistic regression to determine the contributions of behavioral factors, work-related and living conditions to educational inequalities in disability among respondents aged 30-79. RESULTS: We found that adjusting simultaneously for three groups of determinants (behavioral, work-related and living conditions) reduces the greatest proportion of inequalities in disability in both men and women, in a range >70%. Each group of determinants contributes substantially to explain inequalities in disability. CONCLUSIONS: Inequalities in disability are a major challenge for public health in most European countries. Our findings suggest that these inequalities can be reduced by diminishing inequalities in exposure to well-known health determinants

The second-generation antipsychotic drug aripiprazole modulates the serotonergic system in pancreatic islets and induces beta cell dysfunction in female mice

[Aims/hypothesis]: Second-generation antipsychotic (SGA) drugs have been associated with the development of type 2 diabetes and the metabolic syndrome in patients with schizophrenia. In this study, we aimed to investigate the effects of two different SGA drugs, olanzapine and aripiprazole, on metabolic state and islet function and plasticity. [Methods]: We analysed the functional adaptation of beta cells in 12-week-old B6;129 female mice fed an olanzapine- or aripiprazole-supplemented diet (5.5–6.0 mg kg−1 day−1) for 6 months. Glucose and insulin tolerance tests, in vivo glucose-stimulated insulin secretion and indirect calorimetry were performed at the end of the study. The effects of SGAs on beta cell plasticity and islet serotonin levels were assessed by transcriptomic analysis and immunofluorescence. Insulin secretion was assessed by static incubations and Ca2+ fluxes by imaging techniques. [Results]: Treatment of female mice with olanzapine or aripiprazole for 6 months induced weight gain (p<0.01 and p<0.05, respectively), glucose intolerance (p<0.01) and impaired insulin secretion (p<0.05) vs mice fed a control chow diet. Aripiprazole, but not olanzapine, induced serotonin production in beta cells vs controls, likely by increasing tryptophan hydroxylase 1 (TPH1) expression, and inhibited Ca2+ flux. Of note, aripiprazole increased beta cell size (p<0.05) and mass (p<0.01) vs mice fed a control chow diet, along with activation of mechanistic target of rapamycin complex 1 (mTORC1)/S6 signalling, without preventing beta cell dysfunction. [Conclusions/interpretation]: Both SGAs induced weight gain and beta cell dysfunction, leading to glucose intolerance; however, aripiprazole had a more potent effect in terms of metabolic alterations, which was likely a result of its ability to modulate the serotonergic system. The deleterious metabolic effects of SGAs on islet function should be considered while treating patients as these drugs may increase the risk for development of the metabolic syndrome and diabetes.This work was funded by H2020 Marie Sklodowska-Curie ITN-TREATMENT (Grant Agreement 721236, European Commission). We also acknowledge grants RTI2018-094052-B-100/ AEI/10.13039/501100011033 (Ministerio de Ciencia e Innovación y Fondo Europeo de Desarrollo Regional [FEDER]) and S2017/BMD-3684 (Comunidad de Madrid, Spain), and grants from Fundación Ramón Areces (Spain) and CIBERDEM (ISCIII, Spain)

Geoelectrical and electromagnetic methods applied to paleolimnological studies: Two examples from desiccated lakes in the Basin of Mexico

Paleolimnological studies require a broad understanding of the geometry and depth of the sedimentary fill of lake basins prior to coring campaigns. Seismic methods are routinely employed for the indirect characterization of lake-bottom sediments. However, the use of seismic methods might occasionally be limited due to surface conditions or poor seismic contrasts between the stratigraphic units, which lead to data quality that is too poor to provide sufficient information for the selection of drill sites. Sources of cultural noise are one of the main reasons why seismic methods fail in study areas near or within large cities, such as Mexico City. Under certain conditions, electrical and electromagnetic methods might be a suitable substitute or complement to seismic exploration, as they respond to different physical properties of the subsurface. To evaluate the applicability of such methods, here we present two recent case studies from the desiccated lakes Chalco and Xochimilco both located in urban areas within the Basin of Mexico where electrical resistivity tomography (ERT), transient electromagnetic (TEM) and magnetotelluric (MT) soundings were conducted for the characterization of lake basement and lacustrine sediments. In both examples, the results of the geophysical exploration contributed valuable stratigraphic information for the following drilling and core recovery, which highlights the potential of electrical and electromagnetic methods in paleolimnological studies