Fish species ecology in spanish freshwater ecosystems

The life strategies of the Iberian ichthyofauna, poor in species and with a high number of endemisms, are the result of the functioning of the aquatic systems (streams and reservoirs). The majorety of the species wager for iteroparity, high fertility, predominance of males over females and omnivorous feeding habits (short- chain trophic relationships). The fish assemblage is not very structured and depends on the autoecology of the species

Trophic morphoecology in the genus barbus (pisces, cyprinidae)

In this paper the morphological features and feeding habits of three coexisting Barbus species in the Tajo basin (Spain) were studied. Fifteen biometric measurements of each specimen were taken, then eleven morphological variables were calculated, and at the same time, the gastnc contents of each individual were analyzed. The results showed and important relationship of barbillon length, body form, branchial filter and buccal apparatus to size, distribution and food items. The exploitation of available resources in the reservoirs is discussed in the light of the discriminant body differences of the specie

Vanishing DC holographic conductivity from a magnetic monopole condensate

We show how to obtain a vanishing DC conductivity in 3-dimensional strongly coupled QFT's using a massive 2-form field in the bulk that satisfies a special kind of boundary condition. The real and imaginary parts of the AC conductivity are evaluated in this holographic setup and we show that the DC conductivity identically vanishes even for an arbitrarily small (though nonzero) value of the 2-form mass in the bulk. We identify the bulk action of the massive 2-form with an effective theory describing a phase in which magnetic monopoles have condensed in the bulk. Our results indicate that a condensate of magnetic monopoles in a 4-dimensional bulk leads to a vanishing DC holographic conductivity in 3-dimensional strongly coupled QFT's.Comment: 24 pages, 2 figures, accepted for publication in JHE

Identification of the main factors in structuring rotifer community assemblages in ponds of Doñana National Park using the amino acid composition of the species

The use of the role of the species in the habitat (the niche), as an alternative to systematics for studying the processes that determine which and how many species live in a specific habitat (community assembly), is an approach that has been limited by the difficulties in the characterization of the niche. The aim of this study was to identify the determining factors in rotifers' assemblage in several ponds, using the amino acid composition (AAC) of the species as a fingerprint of the differential niche usage. We found that species with a similar AAC and, hence, with a similar trophic niche, spatially co-exist, showing that trophic-niche differentiation is not a main factor in structuring these lentic associations. The negative relationship between amino acid separation and spatial overlap among rotifer species can be considered as evidence that habitat filtering (abiotic factors) is the factor responsible for the assemblages.La utilización del papel de las especies en el habitat (el nicho), como alternativa a la aproximación sistemática, en el estudio de los procesos que determinan cuales y cuantas especies pueden coexistir en un determinado espacio (ensamble de comunidad), se ha visto limitada por las dificultades que existen para caracterizar el nicho. El objetivo de este estudio es identificar los factores determinantes de la asociación de rotíferos en distintas lagunas, utilizando la composición de aminoácidos (CAA) de las especies como un marcador del distinto uso del nicho. Encontramos que las especies con similar CAA, y por lo tanto, nicho trófico, coexisten espacialmente, lo que demuestra que la diferenciación trófica no es un factor estructurador de estas asociaciones leníticas. La relación negativa entre la separación de aminoácidos y el solapamiento especial entre las especies de rotíferos se puede considerar como una evidencia de que el filtro ambiental (factores abióticos) es el factor responsable de las asociaciones. Los resultados muestran que la salinidad y conductividad son las variables más importantes

Ultra-precise analysis of the light curves of CoRoT and Kepler δ Scuti stars

It is well known that the residuals of the multifrequency analysis of δ Scuti stars are correlated, giving rise to challenging features such as a plateau (HD 50844, HD 50870, HD 49434, . . . ) of non-resolved frequencies with amplitude higher than the expected noise level. Several hypotheses have been advanced to explain these features: effective convection, rotation, non-linear interactions, etc. We have recently demonstrated that in some cases the underlying function describing the light variations of δ Scuti stars has not the property of being analytic. The strong consequence of this result is that the Fourier expansion on which the harmonic analysis is based could be not justified. In order to know the extension of this phenomenon among δ Scuti stars, we have used photometric data from CoRoT seismofield and a set of Kepler stars. The results show that this inconsistency in the application of harmonic analysis is almost ubiquitous to the δ Scuti pulsating stars

The Iberian ichthyofauna : ecological contributions

The actual Iberian ichthyofauna is the result of the functioning of the aquatic systems and the human activities. For 27 years the Fish Ecology Research Group of Seville University has worked on understanding the complex relationships established around fish in different water systems and from differents approach scales (life strategies, population dynamics, structure and diversity of the communities, energy, etc.). The work carried out through those years has yielded a huge increase in the knowledge of our continental ichthyofauna. Now we are getting closer to understanding the Iberian epicontinental ecosystems and the ecology role of their fish, a basic need for management and conservation purposes.La actual ictiofauna ibérica es el resultado tanto del funcionamiento de los ecosistemas acuáticos como de las actividades humanas. Durante 27 años, el Grupo de Investigación de Ecología de Peces de la Universidad de Sevilla ha trabajado en la comprensión de las complejas relaciones que giran en torno a la ecología de los peces de nuestros diferentes ecosistemas epicontinentales, abordándolos desde distintas aproximaciones (estrategias de vida, dinámica de sus poblaciones, estructura y diversidad de sus comunidades, energéticas, etc). Los estudios llevados a cabo a lo largo de estos años han contribuido a incrementar el conocimiento de los ecosistemas acuáticos epicontinentales de la Península Ibérica y el papel ecológico de sus peces, conocimientos ambos básicos para el manejo y la conservación de los mismos

Trophic habits of the fish assemblage in an artificial freshwater ecosystem: the Joaquín Costa reservoir, Spain

The Joaquín Costa reservoir contains a mixed fish assemblage of native and exotic species. Feeding habits and feeding relationships of species in the fish assemblage were analysed over a one year cycle. Differences in diet composition were found both between species and within species among seasons. Food overlap and trophic similarity among species also showed seasonal variations. Cluster analysis differentiated four groups of predominant diet: (1) macroinvertebrates (trout and largemouth bass), (2) detritus (nase), (3) cladoceran crustaceans and (4) an omnivorous feeding regime, with large seasonal variations in food habits. Food of fish species included in groups 3 and 4 (roach, white bream, barbel, common and mirror carp) varied seasonally. Using graphical models of feeding strategies, similarity indexes, cluster and multivariate analyses based on the relative importance of food categories in the diet of the species, we illustrate that the fish assemblage showed food resource partitioning according to food habits and foraging habitats within the reservoir

Vitimização durante a pandemia da COVID-19 e sintomas de trauma psicológico em adolescentes precoces e tardios: o papel mediador da solidão

This study aims to analyze the effect of victimization suffered during the COVID-19 lockdown on psychological trauma in early and late adolescents. The sample of this study comprised of 933 Peruvian adolescents, 45.5% (n= 423) were males and (54.5%) (n= 506) were females. 44.5% (n=415) were in early adolescence (12 to 13 years) and 55.5 % (n=518) were in late adolescence (14 to 17 years). Data was collected online during the COVID-19 lockdown. Results show that early adolescents who have suffered victimization have higher probabilities of suffering psychological trauma than late adolescents compared to non- victims. In addition, loneliness is observed to play a significant role as a mediator in the relationship between victimization and psychological trauma in Early Adolescents (B = .69, SE = 0.08, CI [ .53, .86]) and late adolescents (B = .66, SE = 0.07, CI [.51, .81]). Results suggests that the cost-benefit of COVID 19 lockdown should be reconsidered. Social distance could had made difficult for adolescents to stablish interpersonal relationships and solve conflicts associated with victimization. Loneliness could be an expression of these difficulties and therefore explain symptoms of psychological trauma. Finally, results are discussed in order to prevent the harmful effects of the pandemic and the measures taken on adolescent mental health, especially in middle- and low-income countries.Este estudio tiene como objetivo analizar el efecto de la victimización sufrida durante el aislamiento del COVID-19 sobre el trauma psicológico en adolescentes tempranos y tardíos. La muestra de este estudio estuvo conformada por 933 adolescentes peruanos, 45.5% (n=  423) eran varones y (54.5%) (n= 506) eran mujeres. El 44,5% (n=415) estaban en la adolescencia temprana (12 a 13 años) y el 55,5% (n=518) estaban en la adolescencia tardía (14 a 17 años). Los datos se recogieron en línea durante la cuarentena del COVID-19. Los resultados muestran que los adolescentes tempranos que han sufrido victimización tienen mayores probabilidades de sufrir traumas psicológicos que los adolescentes tardíos en comparación con los que no han sido víctimas. Además, se observa que la soledad juega un papel significativo como mediador en la relación entre victimización y trauma psicológico en adolescentes tempranos (B = .69, SE = 0.08, CI [ .53, .86]) y tardíos (B = .66, SE = 0.07, CI [ .51, .81]). Los resultados sugieren que debería reconsiderarse la relación costo-beneficio del aislamiento del COVID 19. La distancia social podría haber dificultado a los adolescentes el establecimiento de relaciones interpersonales y la resolución de conflictos asociados a la victimización. La soledad podría ser una expresión de estas dificultades y, por tanto, explicar los síntomas del trauma psicológico. Por último, se discuten los resultados para prevenir los efectos nocivos de la pandemia y las medidas adoptadas sobre la salud mental de los adolescentes, especialmente en los países de ingresos medios y bajos.Cette étude vise à analyser l’effet de la victimisation subie pendant l’isolement de COVID-19 sur le traumatisme psychologique chez les adolescents précoces et tardifs. L’échantillon de cette étude était composé de 933 adolescents péruviens, dont 45,5 % (n=423) étaient des garçons et 54,5 % (n=506) des filles. 44,5 % (n=415) étaient au début de l’adolescence (12-13 ans) et 55,5 % (n=518) à la fin de l’adolescence (14-17 ans). Les données ont été collectées en ligne pendant la quarantaine COVID-19. Les résultats montrent que les adolescents précoces qui ont été victimes de violence sont plus susceptibles de subir un traumatisme psychologique que les adolescents tardifs, par rapport à ceux qui n’ont pas été victimes de violence. En outre, la solitude joue un rôle significatif en tant que médiateur dans la relation entre la victimisation et le traumatisme psychologique chez les adolescents précoces (B = 0,69, SE = 0,08, IC [ .53, .86]) et tardifs (B = 0,66, SE = 0,07, IC [ .51, .81]). Les résultats suggèrent que le rapport coût-bénéfice de l’isolement COVID 19 devrait être reconsidéré. La distance sociale pourrait avoir rendu plus difficile pour les adolescents l’établissement de relations interpersonnelles et la résolution des conflits associés à la victimisation. La solitude pourrait être l’expression de ces difficultés et expliquer ainsi les symptômes de traumatisme psychologique. Enfin, il examine les résultats obtenus pour prévenir les effets négatifs de la pandémie et les mesures prises en faveur de la santé mentale des adolescents, en particulier dans les pays à revenu faible ou intermédiaire.Este estudo tem como objetivo analisar o efeito da vitimização sofrida durante o isolamento da COVID-19 sobre o trauma psicológico em adolescentes precoces e tardios. A amostra deste estudo foi composta por 933 adolescentes peruanos, 45,5% (n=423) do sexo masculino e 54,5% (n=506) do sexo feminino. 44,5% (n=415) estavam no início da adolescência (12-13 anos) e 55,5% (n=518) estavam no final da adolescência (14-17 anos). Os dados foram coletados on-line durante a quarentena da COVID-19. Os resultados mostram que os primeiros adolescentes que sofreram vitimização têm maior probabilidade de sofrer traumas psicológicos do que os adolescentes tardios, em comparação com aqueles que não sofreram vitimização. Além disso, descobriu-se que a solidão desempenha um papel significativo como mediadora na relação entre vitimização e trauma psicológico em adolescentes precoces (B = 0,69, SE = 0,08, IC [ 0,53, 0,86]) e tardios (B = 0,66, SE = 0,07, IC [ 0,51, 0,81]). Os resultados sugerem que a relação custo-benefício do isolamento da COVID-19 deve ser reconsiderada. O distanciamento social pode ter dificultado o estabelecimento de relacionamentos interpessoais e a resolução de conflitos associados à vitimização. A solidão poderia ser uma expressão dessas dificuldades e, assim, explicar os sintomas de trauma psicológico. Por fim, discute os resultados para evitar os efeitos nocivos da pandemia e as medidas tomadas para a saúde mental dos adolescentes, especialmente em países de baixa e média renda

Observational Δν\Delta\nu-ρˉ\bar\rho relation for δ\delta Sct stars using eclipsing binaries and space photometry

Delta Scuti ($\delta$ Sct) stars are intermediate-mass pulsators, whose intrinsic oscillations have been studied for decades. However, modelling their pulsations remains a real theoretical challenge, thereby even hampering the precise determination of global stellar parameters. In this work, we used space photometry observations of eclipsing binaries with a $\delta$ Sct component to obtain reliable physical parameters and oscillation frequencies. Using that information, we derived an observational scaling relation between the stellar mean density and a frequency pattern in the oscillation spectrum. This pattern is analogous to the solar-like large separation but in the low order regime. We also show that this relation is independent of the rotation rate. These findings open the possibility of accurately characterizing this type of pulsator and validate the frequency pattern as a new observable for $\delta$ Sct stars.Comment: 11 pages, including 2 pages of appendix, 2 figures, 2 tables, accepted for publication in ApJ