221 research outputs found

    Artisanal salt production in Aveiro/Portugal - an ecofriendly process

    Get PDF
    Solar salinas are man-made systems exploited for the extraction of salt, by solar and wind evaporation of seawater. Salt production achieved by traditional methods is associated with landscapes and environmental and patrimonial values generated throughout history. Since the mid-twentieth century, this activity has been facing a marked decline in Portugal, with most salinas either abandoned or subjected to destruction, making it necessary to find a strategy to reverse this trend

    Ciclo anual de oogénesis en Lipophrys pholis (Pisces: Blenniidae)

    Get PDF
    Lipophrys pholis has been shown to be responsive to a variety of environmental contaminants, some of them able to impair reproduction. Description of the normal cycle of oogenesis of this newly proposed sentinel species is important since this data may function as a baseline for comparison in ecotoxicological studies, among other applications. Based on histological observations, L. pholis ovarian development in adult is asynchronous, and 7 ovarian germ cells can be described (oogonia, early and late perinuclear oocytes, cortical-alveolar oocytes, early vitellogenic oocytes, vitellogenic oocytes and spawning oocytes). Using a stereological approach together with the morphologic characteristics of ovarian cells, the ovarian cycle of L. pholis was divided into 3 maturation stages: early oogenesis (May); mid-oogenesis (September), and spawning (November to January). Ovarian cell proportions and gonadosomatic index confirmed that the reproductive period of L. pholis near the southern limit of distribution of the species occurs during cold-water periods, between November and May. The collected data will help to fill some of the gaps in information that still exist on L. pholis oogenesis, thus allowing a better integration of this species as a sentinel for the detection of contaminants in European coastal waters.En trabajos recientes, se ha visto que Lipophrys polis es sensible a diversos contaminantes medioambientales, algunos de los cuales pueden afectar a la reproducción. La descripción del ciclo normal de oogénesis de esta nueva propuesta de especie centinela es importante, ya que serviría como referencia para futuros estudios toxicológicos, entre otras aplicaciones. En base a observaciones histológicas, se pueden describir siete estados de los oocitos (oogonia, estado perinuclear temprano y tardío, estado cortico-alveolar, vitelogénesis temprana, vitelogénesis y oocitos desovados). Desde un enfoque estereológico, junto con las características morfológicas de las células ováricas, el ciclo ovárico de L. polis se ha dividido en tres estados de maduración: oogénesis temprana (mayo), oogénesis media (septiembre) y desove (de noviembre a enero). Las proporciones de las células ováricas y el índice gonadosomático, confirmaron que el periodo reproductivo de L. polis, en el límite meridional de distribución de la especie, se produce durante los periodos de agua fría, entre noviembre y mayo. Los datos obtenidos ayudarán a cubrir algunas de las lagunas que todavía existen en el conocimiento de la ovogénesis de L. pholis, permitiendo, por tanto, una mejor integración de esta especie como centinela para la detección de contaminantes en las aguas costeras europeas

    Simultaneous analysis of 25 phenolic compounds in grape juice for HPLC: method validation and characterization of São Francisco Valley samples.

    Get PDF
    A HPLCmethod for simultaneous determination of 25 phenolic compounds in grape juicewas optimized, validated and applied in the characterization of juices produced in São Francisco Valley (SFV), Brazil. The performance characteristics of the method were established by assays with standard solutions of phenolic compounds, spiked and unspiked samples. Linearity,matrix effects, trueness, precision, detection and quantification limits were evaluated. Linearity was demonstrated in the concentration ranges tested for all phenolic compounds. Significant matrix effects were not identified for the studied compounds.Mean recoveries ranged from86.18 to 106.50%, demonstrating no lack of trueness. Precision of the method was confirmed for the 25 phenolic compounds, with acceptable repeatability relative standard deviations (from 0.71 to 9.24%) and within-reproducibility relative standard deviations (from1.34 to 9.26%) for unspiked and spiked samples. The theoretical limits of detection and quantification of themethod varied from 0.001 to 0.19 Mg mL-1 and 0.003 to 0.37 Mg mL-1, respectively. The results of the validation process showed that the proposed method is fitness for purpose. This method was able to identify simultaneously 25 phenolic compounds and had advantages such as low consumption of solvents and easy sample preparation. The phenolic profile of the grape juices from SFV varied according the grape cultivar. Phenolics of the anthocyanins and tannins class predominated in red grape juices, while in white grape juice phenolic acids and tannins were found at high concentrations

    Symmetry transform in the Faddeev-Jackiw quantization of dual models

    Full text link
    We study the presence of symmetry transformations in the Faddeev-Jackiw approach for constrained systems. Our analysis is based in the case of a particle submitted to a particular potential which depends on an arbitrary function. The method is implemented in a natural way and symmetry generators are identified. These symmetries permit us to obtain the absent elements of the sympletic matrix which complement the set of Dirac brackets of such a theory. The study developed here is applied in two different dual models. First, we discuss the case of a two-dimensional oscillator interacting with an electromagnetic potential described by a Chern-Simons term and second the Schwarz-Sen gauge theory, in order to obtain the complete set of non-null Dirac brackets and the correspondent Maxwell electromagnetic theory limit.Comment: 22 pages, RevTex file, no figur

    Using zebrafish embryo bioassays combined with high-resolution mass spectrometry screening to assess ecotoxicological water bodies quality status: A case study in Panama rivers

    Get PDF
    Several studies show that many water bodies in developing countries are increasingly affected by anthropogenic pressure, such as agricultural activities, domestic and industrial wastewater. However, data is scarce in several of such countries, including Panama. Thus, in this work, the ecotoxicological status of selected rivers in Panama with distinct input sources were evaluated using the zebrafish (Danio rerio) embryo bioassays combined with a liquid chromatography-high resolution mass spectrometry screening of contaminants of emerging concern (CECs), using a library of over 3200 chemicals. A total of 68 CECs, including pharmaceuticals and metabolites, pesticides and several industrial chemicals, could be tentatively identified. Additionally, the zebrafish embryo bioassays showed a significant increase (p < 0.05) in embryo mortality/abnormalities when incubated with water samples from two rivers, Matasnillo and Curundú (47.5% and 32%, respectively). Importantly, a positive correlation between ecotoxicological endpoints and some of the detected CECs was observed. The findings demonstrate that both rivers are under strong anthropogenic pressure, and therefore, management actions are urgently needed to decrease their level of contamination. Overall, this study further supports the use of the zebrafish embryo bioassay as a fast, high throughput approach for screening the toxicity of water samples, and highlights the advantages of combining ecotoxicological assays with high-resolution mass spectrometry to an expedite assessment of the ecotoxicological status of water bodies.This work was supported by the Portuguese Foundation for Science and Technology (FCT) (PTDC|CTA-AMB|31554|2017; UIDB/04423/2020; UIDP/04423/2020), the Spanish Agencia Estatal de Investigación (ref. CTM2017-84763-C3-2-R), the Galician Council of Culture, Education and Universities (ref. ED431C2017/36 and Verónica Castro predoctoral contract, ref. ED481A-2017/156), co-funded by the European Regional Development Fund (ERDF/FEDER).2023-02-02S

    Diet preference reflects the ontogenetic shift in microhabitat use in Lipophrys pholis

    Get PDF
    Based on the heterogenous nature of Lipophrys pholis diet, the stage of the species’ ontogenetic development when major niche shifts occurred was identified, and the causes that force this blennid to change its feeding behaviour, vertical distribution and shelter occupation were considered. The diet analysis of the different size classes consistently showed two clusters, grouping individuals 8 cm total length. This shift occurred simultaneously with the onset of reproduction; it seemed to be independent of inter- and intraspecific competition and reflected a quantitative and qualitative alteration of the dietary constituents. The analysis of the diet of other sympatric intertidal blennids, Lipophrys trigloides and Coryphoblennius galerita, showed that, apart from the first developmental stages, there seemed to be no important dietary overlap. The inevitability of this niche alteration could be explained by the combination of at least two different factors: the development of the scraping capability that enabled the fish to feed on large benthic prey, together with the limited number of suitable shelters that were available in rock pools

    Desenvolvimento de cartilha educativa sobre o uso de adoçantes artificiais

    Get PDF
    A busca por hábitos alimentares mais saudáveis, o controle do diabetes e o grande interesse em manter a boa forma, fez crescer nos últimos anos o uso de adoçantes artificiais como alternativas para substituir o açúcar. Entretanto, a ingestão excessiva destes adoçantes é prejudicial para a saúde, principalmente para gestantes. O presente estudo não condena e nem incentiva o uso de qualquer adoçante artificial, mas busca trazer orientações e advertências quanto ao seu uso e suas peculiaridades. Para isso, utilizou-se como ferramenta uma cartilha explicativa dos efeitos adversos e toxicológicos dos adoçantes Aspartame, Ciclamato de Sódio e Sacarina Sódica. Para esse trabalho, foram feitas buscas nas bases de dados PUBMED e SCIELO, limitando os artigos em idioma (língua inglesa e portuguesa) e ano de publicação (a partir de 2000), usando como palavras-chaves os termos: gestação, adoçantes artificiais, aspartame, ciclamato de sódio e sacarina sódica. O programa utilizado para a diagramação foi o CorelDRAW. Esta cartilha tem como objetivo orientar sobre o uso de adoçantes na alimentação, portanto, para sua elaboração foi desenvolvido um personagem para atrair o leitor, despertar o interesse pela leitura e auxiliar na compreensão da mensagem. Uma formiguinha por "entender" muito bem de sacarose, explica o conteúdo da cartilha, em cima de uma folha de papel. A cartilha inicia com a história do açúcar branco e a definição de adoçantes artificiais. Em seguida são mostradas as principais características dos adoçantes estudados, comparando-os entre si. Recomendações da ANVISA encontram-se ao longo do texto, assim como sugestões de como usá-los e substituí-los. A cartilha elaborada será distribuída após aplicação de questionário exploratório a gestantes que fazem parte do Programa de Estratégia da Família em três postos de atendimento da rede municipal de Volta Redonda. Após um mês um questionário de avaliação do produto será aplicado

    The need for fast-track, high-quality and low-cost studies about the role of the BCG vaccine in the fight against COVID-19.

    Get PDF
    Bacillus Calmette-Guérin (BCG) vaccination is routine and near-universal in many low- and middle-income countries (LMIC). It has been suggested that BCG can have a protective effect on COVID-19 morbidity and mortality. This commentary discusses the limitations of the evidence around BCG and COVID-19. We argue that higher-quality evidence is necessary to understand the protective effect of the BCG vaccine from existing, secondary data, while we await results from clinical trials currently conducted in different settings

    BFFT formalism applied to the minimal chiral Schwinger model

    Full text link
    We consider the minimal chiral Schwinger model, by embedding the gauge noninvariant formulation into a gauge theory following the Batalin-Fradkin-Fradkina-Tyutin point of view. Within the BFFT procedure, the second class constraints are converted into strongly involutive first-class ones, leading to an extended gauge invariant formulation. We also show that, like the standard chiral model, in the minimal chiral model the Wess-Zumino action can be obtained by performing a q-number gauge transformation into the effective gauge noninvariant action.Comment: 11 Latex pages. Revised version: New section and more references included. To appear in MPL
    corecore