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

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 seagrass). H. arguinensis preferred seagrass habitats and did not show a size or life stage-related spatial segregation. Its density was 563 ind. ha−1 and mean movement speed was 10 m per day. Movement speed did not differ between habitats and the direction of movement was offshore during the day and shoreward during the night. Median home range size was 35 m2 and overlap among home ranges was 84%. H. arguinensis' high abundance, close association with seagrass and easy catchability in the intertidal zone, indicate the importance of including intertidal lagoons in future studies on temperate sea cucumber ecology since those systems might require different management strategies than fully submerged habitats

Estimation of growth parameters for the exploited sea cucumber Holothuria arguinensis from South Portugal

Understanding how species grow is critical for choosing appropriate fisheries management strategies. Sea cucumbers shrink during periods of aestivation and have naturally flaccid bodies that make measuring growth difficult. In this study, we obtained length-frequency data on Holothuria arguinensis, measuring undisturbed animals in situ, because it is one of the new target species of the NE Atlantic and Southwestern Mediterranean fisheries. Growth parameters were estimated for individuals inhabiting the Ria Formosa lagoon (Portugal). Length-frequency data were collected between November 2012 and March 2014 by using a visual census augmented with random sampling in 2014. To estimate the asymptotic length (L-infinity) and growth coefficient (K), 2 different growth models were fitted to the length frequency data for 1198 sea cucumbers: the nonseasonal von Bertalanffy and Hoenig seasonal von Bertalanffy models. A L-infinity of 69.9 cm and K of 0.88 were estimated by using the Hoenig function for seasonal growth. The value of 1.0 obtained for the parameter C of this function indicates reduction in growth during winter. The relatively high growth rate (K) of this species may have important implications for its survival, mainly in environments where conditions cause biological stress and oceanic disturbances but may also increase its potential as a candidate for aquaculture.CUMFISH project - Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) [PTDC/MAR/119363/2010]; "Sea cucumber as new marine resource: potential for aquaculture" (CUMARSUR) project - Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) [PTDC/MAR-BIO/5948/2014]; Fundacion para el Futuro de Colombia (Colfuturo); FCT Investigator Programme-Career Development [IF/00998/2014

L'influence de l'âge sur la survie chez les femmes atteintes d'un cancer du sein sans envahissement ganglionnaire

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Investigating the Academic Vocabulary Development of Spanish-English Bilingual Students in Middle School

This study examined the vocabulary development of Spanish-English bilingual adolescents (n= 98) from the end of 6th through the end of 7th grade in a dual language setting by looking at the patterns of growth in English and Spanish vocabulary post intervention and adding to the body of research on vocabulary development. Data were analyzed using descriptive statistics and Hierarchical Linear Modeling (HLM). At the first level (TIME), the analysis helped to describe the shape of each person’s individual growth trajectory and to examine within person variability. The analysis at the second level (STUDENTS) considered inter-individual differences in order to detect heterogeneity in change across individuals and to determine the relationship between predictors and the shape of each person’s individual’s growth trajectory. Evidence for study 1 ~ English Vocabulary Knowledge revealed that on average, students demonstrated significant growth in English vocabulary development. There was significant variation across students with regard to initial status but not with regard to rate of change. In addition, the conditional models suggested that ELL status and initial Spanish cognate knowledge were significantly associated with initial English vocabulary knowledge while English reading comprehension was not. Evidence from study 2 ~ Spanish Cognate Knowledge revealed that on average, students did not demonstrate significant growth in Spanish cognate knowledge. There was significant variation across students with regard to initial status but not with regard to rate of change. In addition, the conditional models suggested that while Spanish comprehension and initial English were significantly associated with initial Spanish cognate knowledge, the ELL status had no effect. Findings from this study align with evidence from previous vocabulary studies showing similar results on the lack of accelerated growth. However, unlike other studies, this study provides reasons to be optimistic about cross-linguistic relationships for Spanish-English bilingual students. The results of this study have implications for designing instruction for Spanish-English bilingual students that is inclusive of more explicit and sustained instruction in both Spanish and English in the area of vocabulary

Analysis of Balmer Profiles of early type stars

The spectral energy distribution (SED) of recent star formation regions is dominated by the more massive and early stars (O and B types). These stars show large and very significant absorption features, the most prominent being the recombination lines of H, HeI and HeII. In particular, the shape of their profiles are very dependent on the luminosity of the star. We have explored the potential use of high resolution profiles to discriminate between different luminosity classes and spectral types, by using profiles of the He and Balmer lines. We have calculated growth curves for each of the lines and their dependence on gravity and effective temperature. We show some of these theoretical growth curves and our preliminary conclusions are analyzed and discussed.Comment: 1 pag, Contribution to the conference "Cosmic Evolution and Galaxy Formation: Structure, Interactions and Feedback", Nov. 1999 (Puebla, Mexico), to be published in ASP. Conf. Series, Eds. J. Franco, E. Terlevich. O. Lopez-Cruz, I. Aretxag

Elysia timida (Risso, 1818) three decades of research

Elysia timida (Risso, 1818) three decades of research.— During the last 30 years, studies on Elysia timida (Risso, 1818) have addressed various aspects related to food sources, photosynthetic efficiency of kleptoplasts, population genetics, chemical ecology and reproductive biology, both in the Mediterranean Sea and in the Mar Menor coastal lagoon. E. timida shows a strong specific interaction with Acetabularia acetabulum, retaining functional chloroplasts for at least 45 days and obtaining extra energy in periods when food resources are scarce. It shows control of parapodia, avoiding pigment photodestruction under oversaturated light conditions. The chemical ecological relationships established between E. timida and its potential predator fish, Thalassoma pavo, have also been evaluated, and it has been found that that the extracts of the mollusc contain repellent and unpalatable polypropionate compounds. Population genetics has demonstrated the genetic divergence between populations showing high and significant values of FST and genetic distances, and at least six privative alleles that are not shared with Mediterranean populations have been detected in lagoon populations. This sacoglossan is a poecilogonic species, and its lagoon populations show a greater reproductive output than Mediterranean populations; they produce a greater number of egg masses and embyros per individual, and the capsules have a wider diameter

The socle of a Leavitt path algebra

In this paper we characterize the minimal left ideals of a Leavitt path algebra as those ones which are isomorphic to principal left ideals generated by line point vertices, that is, by vertices whose trees do not contain neither bifurcations nor closed paths. Moreover, we show that the socle of a Leavitt path algebra is the two-sided ideal generated by these line point vertices. This characterization allows us to compute the socle of some algebras that arise as the Leavitt path algebra of some row-finite graphs. A complete description of the socle of a Leavitt path algebra is given: it is a locally matricial algebra.Comment: 13 pg

Genetic differentiation among Parastichopus regalis populations in the Western Mediterranean Sea: potential effects from its fishery and current connectivity

Parastichopus regalis (Cuvier, 1817) is the most expensive seafood product on the Catalonian market (NE Spain), with prices at approximately 130 €/Kg (fresh weight). Despite its ecological and economic importance, biological and genetic information on this sea cucumber species is scarce. Here, we provide both the first insight on the genetic structure of P. regalis using sequences of cytochrome oxidase I (COI) and 16S genes and a morphological description of its population. Individual sea cucumbers were collected in six locations along the Spanish Mediterranean coast, including an area under fishery pressure (Catalonia). We found high haplotype diversity and low nucleotide diversity for both genes, with higher levels of genetic diversity observed in the COI gene. The population pairwise fixation index (FST), AMOVA and correspondence analysis (CA) based on the COI gene revealed significant genetic differentiation among some locations. However, further analysis using nuclear markers (e.g., microsatellites) is necessary to corroborate these results. Moreover, the genetic and morphological data may indicate fishery effects on the Catalonian population with a decrease in the size and weight averages and lower genetic diversity compared with locations that lack fishery pressure. For the appropriate management of this species, we suggest the following: 1) accurately assessing the stock status along the Spanish coasts; 2) studying the reproductive cycle of this target species and the establishment of a closed fishery season according to the reproductive cycle; and 3) establishing protected areas (i.e., not take zones) to conserve healthy populations and favour recruitment in the nearby areas

Synergistic Activity of Fosfomycin, Ciprofloxacin, and Gentamicin Against Escherichia coli and Pseudomonas aeruginosa Biofilms

Gram-negative (GN) rods cause about 10% periprosthetic joint infection (PJI) and represent an increasing challenge due to emergence of antimicrobial resistance. Escherichia coli and Pseudomonas aeruginosa are among the most common cause of GN-PJI and ciprofloxacin is the first-line antibiotic. Due to emergence of fluoroquinolone resistance, we evaluated in vitro the activity of fosfomycin, ciprofloxacin, and gentamicin, alone and in combinations, against E. coli and P. aeruginosa biofilms. Conventional microbiological tests and isothermal microcalorimetry were applied to investigate the anti-biofilm activity of the selected antibiotics against standard laboratory strains as well as clinical strains isolated from patients with prosthetic joint associated infections. The biofilm susceptibility to each antibiotic varied widely among strains, while fosfomycin presented a poor anti-biofilm activity against P. aeruginosa. Synergism of two-pair antibiotic combinations was observed against different clinical strains from both species. Highest synergism was found for the fosfomycin/gentamicin combination against the biofilm of E. coli strains (75%), including a gentamicin-resistant but fosfomycin-susceptible strain, whereas the gentamicin/ciprofloxacin combination presented synergism with higher frequency against the biofilm of P. aeruginosa strains (71.4%). A hypothetical bacteriolysis effect of gentamicin could explain why combinations with this antibiotic seem to be particularly effective. Still, the underlying mechanism of the synergistic effect on biofilms is unknown. In conclusion, combinatorial antibiotic application has shown to be more effective against biofilms compared to monotherapy. Further in vivo and clinical studies are essential to define the potential treatment regimen based on our results