Distribución intermareal de las poblaciones de macroinvertebrados en el estuario del Tajo, Portugal, en relación con factores ambientales

Fourteen intertidal sites from the eastern mid-region of the Tagus estuary were considered in order to study their macrobenthic assemblages in relation to environmental factors. The salinity gradient was displayed in an ordination of the assemblages by non-metric multidimensional scaling (NMDS). However, salinity was not found to be a significant environmental factor to explain the distribution of the assemblages. Conversely, a lateral gradient characterized three clusters of sites identified in relation to their outer, intermediate and inner location also related to organic matter content, oxygen concentration and redox potential values. Although the hydrodynamic factor was not investigated it is thought to be an important environmental factor for characterizing the lateral gradient. As a general trend, there was a transition between the groups of assemblages from the lower estuary towards the inner and upstream locations. The polychaetes Lanice conchilega and Hediste diversicolor and the gastropod Hydrobia ulvae were the characteristic species in the outer, inner and intermediate groups of sites, respectively. It was concluded that the lateral gradient is the main environmental driver that explains the distribution of the intertidal macrobenthic assemblages in the Tagus estuary when the salinity gradient is not find to be a significant environmental factor.Se han estudiado las poblaciones de macroinvertebrados y su distribución en relación a varios factores ambientales en catorce estaciones de muestreo da la zona intermareal situadas en la región central, margen Este, del estuario del Río Tajo. El gradiente salino fue sobrepuesto sobre las poblaciones macrobentónicas tras aplicar un escalado multidimensional no métrico (NMDS). El análisis reveló que la salinidad no es un factor ambiental significativo en la distribución de las poblaciones macrobentónicas de la zona en estudio. En cambio, se identificó un gradiente lateral que caracterizó los grupos de estaciones de muestreo agrupadas según su localización exterior, interior e intermedia, igualmente relacionadas con los factores ambientales contenido de materia orgánica, concentración de oxígeno y potencial redox. Aunque no se ha medido el factor hidrodinámico, éste parece ser importante para la definición del gradiente lateral. De modo general se observó una transición gradual entre los grupos de poblaciones macrobentónicas desde los situados en la parte de mayor influencia marina hacia aquellos que se distribuyeron en zonas más alejadas del mar en sentido lateral o longitudinal. Los poliquetos Lanice conchilega y Hediste diversicolor y el gasterópodo Hydrobia ulvae fueron las especies características de los grupos de estaciones exterior, interior e intermedio respectivamente. Se ha concluido que el gradiente lateral es el principal condicionante ambiental que explica la distribución de las poblaciones de macroinvertebrados intermareales en el estuario del Río Tajo cuando el gradiente salino no es significativamente importante

Experimento de campo sobre la capacidad reproductiva de la almeja invasiva Mya arenaria en el estuario del rio Tajo: coexistencia con la almeja nativa Scrobicularia plana

A three month field experiment with tidal level (upper, middle, lower) and treatment (excavated and not excavated plots) as categorical experimental factors showed that the invasive clam Mya arenaria has reached a more advanced stage in the invasion process in the Tagus estuary. As we observed the smallest recruited juveniles of Mya arenaria (2 mm) throughout the study period, we concluded that the clam is capable of reproducing in the new habitat. Juveniles of both Mya arenaria and the bivalve Scrobicularia plana were found to avoid excavated experimental plots, showing a significantly higher abundance in the control plots. These data, strongly suggest that the recruited bivalves actively avoid unsuitable substrata. Juvenile specimens of Mya arenaria were more abundant in the mid-intertidal zone. However, juvenile specimens of Scrobicularia plana were mainly distributed in the upper intertidal level, which suggests that they have a different settlement behaviour from that observed for the juveniles of the invasive clam. Despite the divergent distribution between the juveniles of the two species in the study site, the possible interaction between these two species is considered and discussed.La almeja invasiva Mya arenaria ha alcanzado un nuevo estadio invasivo en el estuario del Río Tajo, de acuerdo con los resultados de un experimento de campo que transcurrió durante 3 meses y en el que fueron considerados los factores categóricos elevación intermareal (superior, intermedia e inferior) y tratamiento (unidades experimentales excavadas y no excavadas). La presencia continua durante el tiempo de estudio de juveniles del menor tamaño observado (2 mm) nos permitió deducir que la almeja invasiva es capaz de reproducirse en el nuevo hábitat. Individuos juveniles de Mya arenaria y Scrobicularia plana evitaron las unidades experimentales excavadas, siendo más abundantes en las unidades de control. Esta observación sugiere que los juveniles de ambas especies evitan activamente sustratos poco adecuados. Los juveniles de Mya arenaria se distribuyeron principalmente en la zona intermareal media. Sin embargo, los juveniles de Scrobicularia plana se concentraron principalmente en la región intermareal superior, lo que sugiere un comportamiento de fijación distinto al observado en la almeja invasiva. A pesar de la distribución divergente entre los juveniles, la probable interacción entre las dos especies es considerada y discutida

How nematode morphometric attributes integrate with taxonomy-based measures along an estuarine gradient

Nematodes are highly susceptible to environmental change and possess a wide array of morphological and functional characteristics for the assessment of the “Good Environmental Status”, within Marine Strategy Framework Directive. However, while the taxonomic sufficiency of nematodes in detecting spatial gradients and related ecological niche conditions is well recognized, very little is known about nematodes functional morphometric attributes in response to environmental drivers. To explore this knowledge gap, we aimed to assess the efficacy and efficiency of nematode morphometric attributes (length, width, length/width ratio, biomass) in detecting spatial patterns along a Portuguese estuarine gradient, and compare it with the taxonomic approach. We hypothesized that abundance data weighted by the morphometric attributes will have a higher explanatory power in detecting spatial patterns than using abundance of morphometric data alone. Based on the recent recommendations regarding the time and cost related efficacy of methods in biomonitoring and ecological assessments we also hypothesized that a reduced dataset based on the most common genera will suffice to capture the same distributional patterns displayed by the whole assemblage. Our results demonstrated that dataset solely based on genera abundances had consistently better explanatory power than combined datasets or morphometric datasets alone, however, combined dataset provided different spatial patterns and performed better at discriminating estuary areas. The main gradients described by the taxonomy-based dataset were related to the sediment particle size and water depth. Considering combined datasets, spatial discrimination was mainly driven by the variation in dissolved oxygen % saturation, pointing out to the importance of this variable in determining estuarine conditions substantial for nematodes morphometric distributional patterns. The same analysis repeated for the most frequent genera resulted in similar distributional patterns as for the whole assemblage dataset, clearly demonstrating that spatial estuarine gradients can be sufficiently described by using only the most frequent genera. Such information may substantially increase the efficiency of bioassessment surveys by reducing the cost and work associated with identification and measurements of all of the individual nematode genera.info:eu-repo/semantics/publishedVersio

How nematode morphometric attributes integrate with taxonomy-based measures along an estuarine gradient

Nematodes are highly susceptible to environmental change and possess a wide array of morphological and functional characteristics for the assessment of the “Good Environmental Status”, within Marine Strategy Framework Directive. However, while the taxonomic sufficiency of nematodes in detecting spatial gradients and related ecological niche conditions is well recognized, very little is known about nematodes functional morphometric attributes in response to environmental drivers. To explore this knowledge gap, we aimed to assess the efficacy and efficiency of nematode morphometric attributes (length, width, length/width ratio, biomass) in detecting spatial patterns along a Portuguese estuarine gradient, and compare it with the taxonomic approach. We hypothesized that abundance data weighted by the morphometric attributes will have a higher explanatory power in detecting spatial patterns than using abundance of morphometric data alone. Based on the recent recommendations regarding the time and cost related efficacy of methods in biomonitoring and ecological assessments we also hypothesized that a reduced dataset based on the most common genera will suffice to capture the same distributional patterns displayed by the whole assemblage. Our results demonstrated that dataset solely based on genera abundances had consistently better explanatory power than combined datasets or morphometric datasets alone, however, combined dataset provided different spatial patterns and performed better at discriminating estuary areas. The main gradients described by the taxonomy-based dataset were related to the sediment particle size and water depth. Considering combined datasets, spatial discrimination was mainly driven by the variation in dissolved oxygen % saturation, pointing out to the importance of this variable in determining estuarine conditions substantial for nematodes morphometric distributional patterns. The same analysis repeated for the most frequent genera resulted in similar distributional patterns as for the whole assemblage dataset, clearly demonstrating that spatial estuarine gradients can be sufficiently described by using only the most frequent genera. Such information may substantially increase the efficiency of bio-assessment surveys by reducing the cost and work associated with identification and measurements of all of the individual nematode genera

Evolución de la comunidad de moluscos del lago Sabaudia: causas antropogénicas

The evolution of the molluscan biota in Sabaudia Lake (Italy, central Tyrrhenian Sea) in the last century is hereby traced on the basis of bibliography, museum type materials, and field samplings carried out from April 2009 to September 2011. Biological assessments revealed clearly distinct phases, elucidating the definitive shift of this human-induced coastal lake from a freshwater to a marine-influenced lagoon ecosystem. Records of marine subfossil taxa suggest that previous accommodations to these environmental features have already occurred in the past, in agreement with historical evidence. Faunal and ecological insights are offered for its current malacofauna, and special emphasis is given to alien species. Within this framework, Mytilodonta Coen, 1936, Mytilodonta paulae Coen, 1936 and Rissoa paulae Coen in Brunelli and Cannicci, 1940 are also considered new synonyms of Mytilaster Monterosato, 1884, Mytilaster marioni (Locard, 1889) and Rissoa membranacea (J. Adams, 1800). Finally, human-driven environmental changes and cumulative anthropogenic pressures proved to be the whole driver of the constitution of the human-induced malacofauna studied, casting doubts on the correct use of the definition of "native fauna"

Enhancement in corneal permeability of riboflavin using cyclodextrin derivates complexes as a previous step to transepithelial cross-linking

Corneal cross-linking has been described as an effective treatment to slow the progression of keratoconus. The standard protocol entails corneal epithelial removal to allow the diffusion of riboflavin into the stroma. Although, de-epithelization can generate risks or complications that transepithelial cross-linking tries to solve or avoid. Different formulations were developed after verifying that hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobuthylether-β-cyclodextrin (SBEβCD) in a 20% concentration, increased the solubility of practically insoluble in water drugs such as riboflavin from 0.12 mg/mL to 0.35 mg/mL and 0.29 mg/mL respectively. These values were higher when chitosan and arginine were added to the formulation, showing solubility of 0.78 mg/mL when HPβCD concentration was not modified. Ex vivo corneal permeability was measured after having kept in contact bovine corneas with intact epithelium for 5 h with the 0.1 mg/mL riboflavin solution, the formulations developed and a reproduced nanoemulsion from another work. Riboflavin’s permeability was increased when cyclodextrins, chitosan, and arginine were part of the formulations, compared to the control drug solution. The best permeability coefficient was reached when riboflavin was combined with 40% (w/v) HPβCD, 0.5% (w/w) arginine, and 0.5% (w/w) chitosan. After having carried out toxicity studies as bovine corneal opacity and permeability (BCOP) and Heńs Egg Test - Chorioallantoic Membrane Test (HET-CAM) it was verified that both, the active ingredients and the excipients of the different formulations were not harmful without generating irritation, loss of transparency or corneal permeability alterations. The results show the great potential of the ocular developed solution for their use in transepithelial cross-linking for keratoconus treatmentS

Does lack of knowledge lead to misperceptions? Disentangling the factors modulating public knowledge about and perceptions towards sharks

Identifying sources of variability in public perceptions and attitudes toward sharks can assist managers and conservationists with developing effective strategies to raise awareness and support for the conservation of threatened shark species. This study examined the effect of several demographic, economic and socioenvironmental factors on the quality of knowledge about and perceptions toward sharks in two contrasting scenarios from northeastern Brazil: a shark hazardous coastal region and a marine protected insular area. Ordered logistic regression models were built using Likert data collected with a self-administered questionnaire survey (N = 1094). A clear relationship between education, knowledge and perceptions was found, with low education level and knowledge of sharks resulting in more negative perceptions toward these species. Prejudice toward sharks stemmed as a potentially limiting factor because the positive effects of other variables such as affinity for nature and specific knowledge about sharks were superseded by the effects of negative prejudice. Other practical factors such as age, economic level, and gender, also influenced respondent’s knowledge and perceptions and could provide a guidance for optimizing socioenvironmental gains relative to public engagement efforts. Results also suggested that populations inhabiting regions with high shark bite incidence likely require distinct outreach methods because some factors underlying knowledge and perception dynamics exhibited structural differences in their effects when compared to the trends observed in a marine protected area. Altogether, public perceptions and attitudes toward sharks could be feasibly enhanced with educational development and nature experiencing strategies. Moreover, disseminating shark-specific knowledge across the society might catalyze support for the conservation of these species in a cost-effective way. This study provides a Frontiers in potentially useful socioenvironmental framework to deal with the human dimensions of shark management and to strengthen conservation policies aimed at promoting societal compliance with pro-environmental values, which is crucial to endow shark populations with effective protection from anthropogenic threats.info:eu-repo/semantics/publishedVersio

Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations

The treatment of the posterior-segment ocular diseases, such as age-related eye diseases (AMD) or diabetic retinopathy (DR), present a challenge for ophthalmologists due to the complex anatomy and physiology of the eye. This specialized organ is composed of various static and dynamic barriers that restrict drug delivery into the target site of action. Despite numerous efforts, effective intraocular drug delivery remains unresolved and, therefore, it is highly desirable to improve the current treatments of diseases affecting the posterior cavity. This review article gives an overview of pharmacokinetic and biopharmaceutics aspects for the most commonly-used ocular administration routes (intravitreal, topical, systemic, and periocular), including information of the absorption, distribution, and elimination, as well as the benefits and limitations of each one. This article also encompasses different conventional and novel drug delivery systems designed and developed to improve drug pharmacokinetics intended for the posterior ocular segment treatment

Just use it! Linguistic conversion and identities of resistance amongst Galician new speakers

In recent years there has been a focus in language policy research on understanding how national policies are interpreted and negotiated by social actors on the ground. This paper looks at the interplay between government and grassroots initiatives to create Galician-speaking spaces in predominantly Spanish-speaking urban settings. While official language policies in Galicia since the 1980s have increased the potential for language use through bilingual educational policies, these policies have failed to convert the large pool of potential speakers amongst a younger generation of Galicians into active language users. Drawing on ethnographic fieldwork and in-depth interviews with Galician neofalantes (new speakers) this paper looks at instances where such policies seem to have worked and where the linguistic capacity created through the education system has been converted into active language use. The article examines how such speakers rationalise their practice of linguistic conversion not as success stories of language policy but as reactions to and dissatisfaction with what is perceived as ‘top-down’ governmentality through a reflexive process in which existing power structures are brought into question. The article looks specifically as the ideologies underpinning their decisions to become active speakers and the role they play as language planners in contemporary Galicia