Relationships between diatoms and the environment in Spanish reservoirs

Diatoms are very useful environmental indicators in limnological and paleolimnological studies. Spanish reservoirs offer a valuable opportunity for the study of relationships between diatoms and environmental conditions, since these ecosystems are abundant in this country and the patterns of their regional limnology are well established. We report the results from a study carried out on diatom communities in 40 reservoirs from several Spanish water basins. More than 200 diatom taxa were found. A canonical correspondence analysis was applied to the abundance data of the most common taxa and the main physical and chemical variables. This analysis showed that mineralisation (conductivity and alkalinity) was the most important environmental factor explaining diatom distribution, while trophic state was the second most important. These results are similar to those in previous studies on phytoplankton in Spanish reservoirs. Conductivity and alkalinity optima of the selected taxa allow us to consider these taxa as good indicators of water mineral content in similar ecosystems.Las diatomeas son indicadores ambientales muy útiles en estudios limnológicos y paleolimnológicos. En España los embalses ofrecen una gran oportunidad para el estudio de las relaciones entre las diatomeas y las condiciones ambientales, ya que son ecosistemas muy abundantes y las principales características de su limnología regional están bien estudiadas. Se presentan aquí los resultados de un estudio sobre las comunidades de diatomeas efectuado en 40 embalses de diversas cuencas hidrográficas españolas. En ellos se encontraron más de 200 taxones de diatomeas. Se efectuó un análisis de correspondencias canónicas con los datos de abundancia de los taxones más frecuentes y las principales variables físico-químicas. Este análisis muestra que el factor con mayor influencia sobre las comunidades de diatomeas es la mineralización (conductividad y alcalinidad), y en segundo lugar el grado trófico. Estos resultados son similares a estudios previos sobre el fitoplancton de embalses españoles. Los valores de los óptimos respecto a la conductividad y alcalinidad de los principales taxones, permiten considerar dichos taxones como buenos indicadores del contenido mineral del agua en ecosistemas similares

Tell me your age and I tell you what you trust: the moderating effect of generations

Purpose: The proliferation of social commerce websites has allowed consumers to share and exchange information, experiences, advice and opinions. Recently, information provided by users has been considered more trustworthy than the information shared by companies. However, the way in which users interact with technology can vary with age, and generational cohorts show different shopping behaviors, interests and attitudes. Hence, the way users process information (user-generated vs company-generated) can affect trust differently. Drawing on the trust transfer theory and the generational cohort theory, the purpose of this paper is to analyze the effects on user- and company-generated information in boosting trust of three different cohorts (Generation X, Y and Z). Design/methodology/approach: The data were collected through an online survey. The sample comprised 715 users of social commerce websites, aged between 16 and 55 years old. The study was analyzed using partial least squares with the statistical software Smart PLS 3. Findings: The empirical results show that generational cohorts show different patterns. Generation X transfers trust to social commerce websites mainly from trust in information generated by companies, while Generation Z transfers trust mainly from information generated by users. Finally, Generation Y, in contrast to previous findings about millennials, develops trust based on company-generated information to an even greater extent than does Generation X. Originality/value: The originality of this study lies in its analysis of generational differences when it comes to trusting one type of information over another. This study contributes to the idea that users cannot be considered as a whole but must be segmented into generational cohorts

Social commerce users'' optimal experience: stimuli, response and culture

Social commerce users' experience is generated during socio-commercial interactions. Therein, users receive utilitarian and hedonic stimuli that form their experience and influence their responses. However, research is needed to understand how this experience is generated. Based on the stimulus-organism-response framework and flow theory, this study analyzes how hedonic stimulus (here called sPassion) and utilitarian stimulus (usability) affect users' flow experience (organism) to positively impact emotional and behavioral loyalty (users' responses). Furthermore, as social commerce users are culturally diverse, the moderating effect of cultural background is studied, drawing on Hofstede's cultural dimensions. Findings show that hedonic stimulus more strongly impacts social commerce users' flow experience versus utilitarian stimulus. Once users reach the state of optimal experience, their positive responses are reflected in their increased intention to spread social word of mouth, to return to the website and to repurchase on it. Additionally, optimal user experience in social commerce is generated mainly through hedonic stimuli and, while social commerce environments can be culturally diverse, cultural background does not imply changes in users' behavioral patterns. This study theoretically advances research on social commerce users' experience. Likewise, the findings guide online retailers in optimizing user experience via hedonic stimuli to enhance loyalty

From sPassion to sWOM: The role of flow

Purpose - Social commerce websites entail a completely new scenario for sharing experiences and opinions due to its richness in terms of social interactions. Nowadays, users can interact with the company and with other users; hence, it seems important to study how social stimuli affect users. Drawing on the stimulus-organism-response framework and flow theory, the purpose of this paper is to propose that the social stimulus (named social passion (sPassion)) has a positive effect on the organism (state of flow), which leads to a users' positive response (via social word of mouth (sWOM)). Design/methodology/approach - The data were collected through an online survey in 2015. The sample consists of 771 users of social commerce websites, of which 51 percent are male and 49 percent female, aged between 16 and 80 years old. Structural equation modeling was used to analyze the data with the statistical software SPSS version 22 and EQS 6. Findings - The empirical results confirm that passionate users are prone to experience a state of flow and, as a consequence, share positive sWOM. Originality/value - This study contributes to the literature on customers' online participation, and the findings are hoped to help companies in developing social commerce websites that boost users' exchange of information

The mediated effect of social presence on social commerce WOM behavior

Based on expectation disconfirmation theory, this study analyzes how attitudes (satisfaction and loyalty) influence interaction intention (sWOM) and, consequently, active and passive sWOM behavior. It does so by assessing the mediating role of social presence on sWOM intention and behavior. The empirical results provide several contributions. First, knowing how to increase active sWOM contributes to bridging the gap regarding how to enhance interactions between users. Second, fostering active sWOM on social commerce websites will provide companies with more positive user-generated content, since this active sWOM comes from satisfied and loyal users, and it is assumed that they will rate the product positively and report a good experience. Third, companies can benefit more from users if users interact with other users by sharing their experiences. This study sheds light on how social presence can mediate the relationship between intention and behavior, particularly when it comes to increasing active participation and brand promotion. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Nuevos datos morfométricos para el Lago de Sanabria

Se presenta un nuevo mapa batimétrico del lago de Sanabria, con curvas de nivel situadas a cada metro de profundidad y algunos parametros morfométricos. La forma de este lago, basándonos en la curva hipsográfica relativa del área frente a la profundidad es cóncava (C). Este lago tiene altos valores de los parámetros: desarrollo del volumen (Dv) y la relación de profundidad (cociente profundidad media / profundidad máxima: zm / zmax), esto refleja su morfometría con un fondo considerablemente plano y grandes pendientes desde las orillas hacia el mismo, como ocurre en algunos tipos de lagos de origen glaciar. La profundidad relativa (Zr) es intermedia y los índices: área de la cuenca / volumen del lago (Ac / V) y área de la cuenca / área del lago (Ac / A) son bastante altos, si los comparamos con otros lagos. El valor de estos parámetros indica la gran influencia de los factores externos sobre la dinámica del lago.A new bathymetric map of Lake Sanabria is presented, showing depth isolines each meter and some morphometric parameters. The lake form, based on the relative hypsographic curve (cumulative area-depth), is concave (C). This lake shows high values of volume development (Dv) and of the depth relation (mean depth / maximal depth ratio: zm / zmax), which indicates a nearly flat bottom and high slopes in the shores, like those of some types of glacial lakes. The relative depth (Zr) has an intermediate value and the indexes: basin area / lake volume (Ac / V) and basin area / lake area (Ac / A) are quite high, when compared to other lakes. The values of these parameters indicate the large influence of external factors on the lake dynamics

Cyanobacteria distribution and abundance in the Spanish water reservoirs during thermal stratification

A study of the distribution and abundance of Cyanobacteria in 47 Spanish water reservoirs revealed a significant correlation between these algae and total phosphorus in the water. Cyanobacteria distribution was related to the N:P ratio, and they were scarce when the atomic ratio of total inorganic N / total P exceeded 50. The N:P ratio was influenced by the geology of the catchment, and it was lower in the solute-poor waters of western Iberian Peninsula, where Cyanobacteria were more abundant (mainly the Nostocales). Therefore, this area would be more prone to present problems derived from Cyanobacteria proliferation than the eastern part of Spain. In the studied reservoirs we have recorded 45 taxa of Cyanobacteria, many of which can produce toxins. A comparison of our results with those of previous studies served to conclude that Cyanobacteria have increased both in biomass and species number in Spanish reservoirs.El estudio de la distribución y abundancia de Cianobacterias en 47 embalses españoles reveló una correlación significativa entre estas algas y la concentración de fósforo total en el agua. La distribución de Cianobacterias estuvo relacionada con el cociente N:P, siendo generalmente poco abundantes cuando la relación atómica N inorgánico total / P total fue superior a 50. La relación N:P en el agua está influenciada por la geología de la cuenca, y fue menor en las aguas menos mineralizadas del oeste de la Península Ibérica, donde las cianobacterias fueron más abundantes (especialmente las nostocales). Por lo tanto, esta zona de la península Ibérica sería más propensa a sufrir problemas relacionados con la proliferación de Cianobacterias que la zona este de España. En los embalses estudiados hemos encontrado 45 taxones de Cianobacterias, muchas de las cuales pueden producir toxinas. La comparación de nuestros resultados con estudios realizados previamente sirvió para concluir que en los embalses españoles se ha producido un aumento del número de especies y de la biomasa de Cianobacterias

Synchrotron radiation photoionization mass spectrometry of laser ablated species

The present paper describes an experimental apparatus suitable to create and study free clusters by combining laser ablation and synchrotron radiation. First tests on sulfur samples, S, showed the production, through laser ablation, of neutral Sn clusters (n = 1–8). These clusters were ionized using synchrotron radiation at photon energies from 160 eV to 175 eV, across the S 2p core edge. The feasibility of such combined ablation–synchrotron radiation experiments is demonstrated, opening new possibilities on the investigation of free clusters and radical

Emotional responses in online social interactions: the mediating role of flow

Purpose: Drawing on the three flow-channel model and the stimulus–organism–response model, this research aims to understand how the influence of interactivity on purchase intention is mediated by the state of flow. Design/methodology/approach: This research entails a neurophysiological experiment combined with a survey-based study. This study analyzes, first, participants' heart rate variability through the parasympathetic and sympathetic indexes during five different activities, and, second, the mediating effect of flow through a structural equation model. Findings: This study contributes to research on the role of flow in interactive marketing. The findings reveal that flow state is associated with less stressful activities, such as navigating highly interactive websites and playing online games. This research confirms the mediating effect of flow between interactivity and purchase intention. Originality/value: This paper contributes to interactive marketing and flow theory by combining traditional methods with a peripheral physiological technique that draws on neuroscience. In addition, it confirms the positive but indirect effect of interactivity on purchase intention in online contexts