Mostrando recursos 1 - 20 de 660

  1. The VES hypothesis and protein conformational changes

    Cruzeiro, Leonor
    This work started as a (biased) review of the state of the art of the Davydov/Scott model for energy transfer in proteins via the propagation of amide I excitations and of how this initial quantum stage may lead to protein conformational changes. It is not a traditional review because certain results reported in the literature have been complemented by extra simulations which revealed, for instance, a new class of possible states for the amide I excitation, here designated as double discrete breathers. The issue of the thermal stability of the Davydov soliton is discussed, as well as the deeper question...

  2. Empregabilidade e transição para o mercado de trabalho: perspetivas de estudantes/diplomados não-tradicionais do Ensino Superior

    Paulos, Liliana; Valadas, Sandra; Fragoso, António
    Considerando os desafios que os estudantes não-tradicionais enfrentam, quer na participação no Ensino Superior, quer na sua transição para o mercado de trabalho, foi nossa intenção compreender a) Qual a perspetiva dos estudantes sobre as competências/capacidades que os tornam empregáveis? e b) Quais os desafios que enfrentam na transição para o mercado de trabalho? Nesta lógica, foram realizadas 21 entrevistas biográficas a estudantes/diplomados não-tradicionais que frequentavam o último ano da licenciatura, mestrado ou mestrado integrado. As dimensões analisadas remetem para as questões de género, idade e experiência, e contexto socioeconómico. Os resultados sugerem uma internalização dos discursos sobre empregabilidade, entendida pelos participantes como uma responsabilidade individual para obter/manter um emprego. Os participantes referem...

  3. Efficacy of Electrolyzed Water to Inactivate Foodborne Pathogens on Fresh-Cut Apples

    Graça, A.; Nunes, C.; Quintas, C.; Abadias, M.; Usall, J.; Salazar, M.
    Chlorine is the most common disinfectant used in the fresh-cut industry but nowadays environmental and health risks have led to the need to find new sanitizers. Electrolyzed water (EW) appears to be a promising alternative. In this work, disinfection efficacy of acidic (AEW) and neutral (NEW) electrolyzed water in fresh-cut apple slices inoculated with Escherichia coli, Listeria innocua or Salmonella choleraesuis was studied. Apple slices were inoculated with a 10(7) cfu/ml suspension of pathogens and treated with the sanitizer EW solutions, with 100 or 50 ppm of free chlorine solutions and with distilled water. Population reduction was determined 30 min...

  4. Efficiency of triple emitter source (TES) for irrigation experiments of horticultural crops

    Beltrão, J.; Jesus, S. B.; Silva, V.; Sousa, P. B.; Carvalho, Isabel Saraiva de; Trindade, D.; Rodrigues, M. H.; Machado, A.
    Triple emitter source TES experimental irrigation was designed. Three trickle laterals were connected together in order to form a triple joint lateral. Two of them and their emitters are connected to two tanks of stock solutions. The third lateral contains only fresh water. The emitters of the two solution lines have different and varying discharges to obtain several mixings of the two stock solutions. The third line is necessary to obtain constant water application rates for each trickling point along the lateral. This method was tested for several experiments involving the study of the combined effects of salinity and fertilizers...

  5. Alternative codends to reduce bycatch in Chilean crustacean trawl fisheries

    Queirolo, Dante; Erzini, Karim; Hurtado, Carlos F.; Ahumada, Mauricio; Soriguer, M. C.
    This study was conducted to determine the reduction in bycatch and the loss of target catch in trawl hauls for three commercial crustacean species (yellow squat lobster, Cervimunida johni, nylon shrimp, Heterocarpus reedi, and red squat lobster, Pleuroncodes monodon) in central Chile. Two experiments were carried out using the covered codend method; the first used different mesh sizes (56 and 70 mm, knot-centre to knot-centre) and shapes (diamond and square), and the second tested different reduction devices (escape panel and sorting grid). We analysed the escape proportions of the species caught and the size frequency distributions of the target species...

  6. Length-weight relationships of six syngnathid species from Ria Formosa, SW Iberian coast

    Vieira, R. P.; Monteiro, P.; Ribeiro, J.; Bentes, L.; Oliveira, F.; Erzini, Karim; Gonçalves, J. M. S.
    In this study, the length-weight (LWR) parameters were estimated for six syngnathid species, including 2 seahorses and 4 pipefishes, from Ria Formosa, a temperate lagoon from the south coast of Portugal. A total of 5070 fishes were used to determine the LWR. The estimated b value ranged from 2.95 (Nerophis ophidion) to 3.36 (Syngnathus abaster). To the authors' best knowledge, LWR parameters were estimated for the first time for Nerophis ophidion and Syngnathus typhle for the Atlantic waters. Data here present are essential for management and conservation of these flagship species.

  7. Genetic considerations on the introduction of farmed fish in marine protected areas: The case of study of white seabream restocking in the Gulf of Castellammare (Southern Tyrrhenian Sea)

    Gonzalez-Wangueemert, Mercedes; Fernandez, Tomas Vega; Perez-Ruzafa, Angel; Giacalone, Maximilian; D'Anna, Giovanni; Badalamenti, Fabio
    Human exploitation has drastically reduced the abundance and distribution of several marine fish and invertebrate populations through overfishing and habitat destruction. Restocking can potentially mitigate these impacts and help to reconstitute depleted stocks but genetic repercussions must be considered. In the present study, the degree of genetic similarity between white seabream (Diplodus sargus Linnaeus 1758) individuals reared for restocking purposes and the receiving population in the Gulf of Castellammare fishery reserve (Sicily, Italy) was assessed using microsatellites. We also inferred the spatial pattern of the genetic structure of D. sargus and connectivity along Sicilian coasts. The farmed population showed significant heterozygosity deficiency in 6 loci and an...

  8. Genetic diversity across geographical scales in marine coastal ecosystems: Holothuria arguinensis a model species

    Rodrigues, F.; Valente, Sara; Gonzalez-Wanguemert, M.
    Coastal lagoons are considered one of the most productive areas of our planet harboring a large variety of habitats. Their transitional character, between terrestrial and marine environments, creates a very particular ecosystem with important variations of its environmental conditions. The organisms that are able to survive on these ecosystems frequently experience strong selective pressures and constrictions to gene flowwith marine populations, which could contribute to genetic divergence among populations inhabiting coastal lagoon and marine environments. Therefore, the main aims of this study are to asses the genetic diversity and population structure of Holothuria arguinensis across geographical ranges, to test the hypothesis of coastal lagoons as hotspots...

  9. Connectivity patterns inferred from the genetic structure of white seabream (Diplodus sargus L.)

    Gonzalez-Wangueemert, M.; Canovas, F.; Perez-Ruzafa, A.; Marcos, C.; Alexandrino, P.
    Themarine environment seems, at first sight, to be a homogeneousmediumlacking barriers to species dispersal. Nevertheless, populations of marine species show varying levels of gene flow and population differentiation, so barriers to gene flow can often be detected. Weaimto elucidate the role of oceanographical factors ingenerating connectivity among populations shaping the phylogeographical patterns in the marine realm, which is not only a topic of considerable interest for understanding the evolution ofmarine biodiversity but also formanagement and conservation of marine life. For this proposal,we investigate the genetic structure and connectivity between continental and insular populations ofwhite seabreamin North East Atlantic (NEA) and Mediterranean Sea (MS) aswell as the influence...

  10. Connectivity patterns inferred from the genetic structure of white seabream (Diplodus sargus L.)

    Gonzalez-Wangueemert, M.; Canovas, F.; Perez-Ruzafa, A.; Marcos, C.; Alexandrino, Paulo
    Themarine environment seems, at first sight, to be a homogeneousmediumlacking barriers to species dispersal. Nevertheless, populations of marine species show varying levels of gene flow and population differentiation, so barriers to gene flow can often be detected. Weaimto elucidate the role of oceanographical factors ingenerating connectivity among populations shaping the phylogeographical patterns in the marine realm, which is not only a topic of considerable interest for understanding the evolution ofmarine biodiversity but also formanagement and conservation of marine life. For this proposal,we investigate the genetic structure and connectivity between continental and insular populations ofwhite seabreamin North East Atlantic (NEA) and Mediterranean Sea (MS) aswell as the influence...

  11. Population genetics of Cerastoderma edule in Ria Formosa (southern Portugal): the challenge of understanding an intraspecific hotspot of genetic diversity

    Vergara-Chen, Carlos; Rodrigues, Fernanda; Gonzalez-Wangueemert, Mercedes
    Coastal lagoons are highly variable environments that may act as hotspots of genetic diversity as a consequence of their ecological role as nursery habitats of marine species with both ecological and fisheries importance. The edible cockle (Cerastoderma edule) is a commercially important shellfish resource inhabiting coastal lagoons in Europe and their fisheries management urgently needs genetic studies to design appropriate strategies to promote the recovery of exploited populations. The aim of this study was to assess the C. edule genetic diversity and population structure at a small geographic scale, inside Ria Formosa coastal lagoon (southern Portugal) using mitochondrial cytochrome oxidase I sequences in six locations. Outcomes...

  12. Phylogeography of the Atlanto-Mediterranean sea cucumber Holothuria (Holothuria) mammata: the combined effects of historical processes and current oceanographical pattern

    Borrero-Perez, G. H.; Gonzalez-Wangueemert, M.; Marcos, C.; Perez-Ruzafa, A.
    We assessed the genetic structure of populations of the widely distributed sea cucumber Holothuria (Holothuria) mammata Grube, 1840, and investigated the effects of marine barriers to gene flow and historical processes. Several potential genetic breaks were considered, which would separate the Atlantic and Mediterranean basins, the isolated Macaronesian Islands from the other locations analysed, and the Western Mediterranean and Aegean Sea (Eastern Mediterranean). We analysed mitochondrial 16S and COI gene sequences from 177 individuals from four Atlantic locations and four Mediterranean locations. Haplotype diversity was high (H = 0.9307 for 16S and 0.9203 for COI), and the haplotypes were closely related (p = 0.0058 for 16S and 0.0071...

  13. Small-scale genetic structure of Cerastoderma glaucum in a lagoonal environment: potential significance of habitat discontinuity and unstable population dynamics

    Vergara-Chen, Carlos; Gonzalez-Wangueemert, Mercedes; Marcos, Concepcion; Perez-Ruzafa, Angel
    Environmental heterogeneity in coastal lagoons is expected to facilitate local adaptation in response to different ecological conditions, causing significant genetic structuring within lagoon populations at a small scale and also differentiation between lagoons. However, these patterns and processes of genetic structuring are still poorly understood. The aims of our study were (1) to seek genetic structure at a small scale in Cerastoderma glaucum inside the Mar Menor coastal lagoon using a mitochondrial DNA marker (COI) that has previously detected genetic differentiation inside the lagoon in other species and (2) to evaluate the influence of extreme environmental conditions and habitat discontinuity on its genetic composition. The results indicate...

  14. Do hatchery-reared sea urchins pose a threat to genetic diversity in wild populations?

    Segovia-Viadero, M.; Serrão, E. A.; Canteras-Jordana, J. C.; Gonzalez-Wangueemert, Mercedes
    In salmonids, the release of hatchery-reared fish has been shown to cause irreversible genetic impacts on wild populations. However, although responsible practices for producing and releasing genetically diverse, hatchery-reared juveniles have been published widely, they are rarely implemented. Here, we investigated genetic differences between wild and early-generation hatchery-reared populations of the purple sea urchin Paracentrotus lividus (a commercially important species in Europe) to assess whether hatcheries were able to maintain natural levels of genetic diversity. To test the hypothesis that hatchery rearing would cause bottleneck effects (that is, a substantial reduction in genetic diversity and differentiation from wild populations), we compared the levels and patterns of...

  15. Spatial distribution patterns and movements of Holothuria arguinensis in the Ria Formosa (Portugal)

    Siegenthaler, Andjin; Canovas, Fernando; Gonzalez-Wangueemert, Mercedes
    Holothurian populations are under pressure worldwide because of increasing demand for beche-de-mer, mainly for Asian consumption. Importations to this area from new temperate fishing grounds provide economic opportunities but also raise concerns regarding future over-exploitation. Studies on the habitat preferences and movements of sea cucumbers are important for the management of sea cucumber stocks and sizing of no-take zones, but information on the ecology and behavior of temperate sea cucumbers is scarce. This study describes the small-scale distribution and movement patterns of Holothuria arguinensis in the intertidal zone of the Ria Formosa national park (Portugal).Mark/recapture studieswere performed to record theirmovements over time on different habitats (sand and...

  16. Characterization of 10 new tetranucleotide microsatellite markers for the European eagle owl, Bubo bubo: Useful tools for conservation strategies

    Leon-Ortega, Mario; Gonzalez-Wangueemert, Mercedes
    Bubo bubo is the largest owl in the world, showing a wide geographical distribution throughout the Palaearctic region. It underwent a demographic decline in many European countries during the last century and was considered “vulnerable” (Annex II of the CITES). Nowadays, it is classified as “Least Concern” according to IUCN. Despite its ecological importance and conservation status, few polymorphic molecular markers are available to study its diversity and population genetics. We report on the isolation and development of 10 new microsatellites for the Eagle owl, B. bubo. All loci (10 tetra-nucleotide) are characterized by high polymorphism levels. Number of alleles ranged from 5 to 13 and expected heterozygosity...

  17. Genetic evidence for polygynandry in the black-striped pipefish syngnathus abaster: a microsatellite-based parentage analysis

    Huebner, Kerstin; Gonzalez-Wanguemert, Mercedes; Diekmann, O. E.; Serrão, Ester
    Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy...

  18. In two waters: contemporary evolution of lagoonal and marine white seabream (Diplodus sargus) populations

    Gonzalez-Wangueemert, Mercedes; Perez-Ruzafa, Angel
    Brackish water ecosystems are often exposed to wide variations in environmental variables, including temperature and salinity, which may cause strong selective pressures on organisms modifying the genetic patterns of species. The aim of this work was to test whether there is a ‘divergence-with-gene flow’ in coastal lagoon populations of white seabream (Diplodus sargus) (Ria Formosa, S Portugal and Mar Menor, SE Spain) respect to four marine populations, by using partial sequences of cyt b mitochondrial gene and information from nine microsatellite loci. Genetic diversity was highest in both coastal lagoons (Mar Menor and Ria Formosa) considering mitochondrial and nuclear markers. Although some of FST population pairwise comparisons were not...

  19. Assessment of sea cucumber populations from the Aegean Sea (Turkey): first insights to sustainable management of new fisheries

    Gonzalez-Wangueemert, Mercedes; Aydin, Mehmet; Conand, Chantal
    Sea cucumber stocks have been overfished in many countries. As a consequence, several species (Holothuria polii, Holothuria tubulosa and Holothuria mammata) are now caught in Turkish waters without adequate knowledge on their biology and ecology. Here, we address their morphometry, relationships among gutted length and weight, population dynamics, temporal evolution of catches, and we provide the first insights about technical aspects of their fisheries. The largest size classes of H. polii are missing from our sampling collection, possibly due to the heavy fishery pressure on this species. Significant differences in the eviscerated length and weight were found among the Turkish sampled localities for H. polii and H....

  20. West versus East Mediterranean Sea: origin and genetic differentiation of the sea cucumber Holothuria polii

    Valente, Sara; Serrão, Ester; Gonzalez-Wangueemert, Mercedes
    We studied the genetic structure of the sea cucumber Holothuria (Roweothuria) polii (Delle Chiaje 1823) by analysing the mitochondrial DNA variation in two fragments of cytochrome oxidase I (COI) and 16S genes. Individuals were collected in seven locations along the Mediterranean Sea, which cover a wide range of the species distribution. We found high haplotype diversity for COI and moderate diversity for 16S, and low nucleotide diversity for both genes. Our results for the COI gene showed many recent and exclusive haplotypes with few mutational changes, suggesting recent or ongoing population expansion. The Western and Eastern Mediterranean populations exhibited slight but significant genetic differentiation (COI gene) with higher genetic...

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