The diatom Chaetoceros in ships’ ballast waters – survivorship of stowaways

Ship ballast water discharged by vessels into the receiving port is recognised today as an important vector for the spread of non-indigenous species and facilitates the introduction of potential invasive species. Here, we report on 18 species (of about 30 identified), both vegetative cells and spores, of the diatom genus Chaetoceros Ehrenberg found in ballast water collected from ships arriving at Canadian ports on theWest Coast (WC), East Coast (EC) and the Great Lakes (GL). We found live, vegetative Chaetoceros cells (one of the most abundant taxa) in 49% of the 57 ballast water samples. The highest density of viable spores enumerated in our counts was 414 cells L–1. In 62% of 52 samples examined using scanning electron microscopy (SEM), Chaetoceros spores were found, though fewer live, identifiable spores were found using light microscopy. Three reportedly harmful species, C. convolutus, C. danicus, C. debilis were encountered in WC samples, and additionally, C. cf. hispidus, a species not yet reported from Canada. C. ceratosporus and C. cf. subsecundus, to date reported only from the EC of the USA, now have been transported to the port of Vancouver, British Columbia. Our findings contribute to the assessment of the effectiveness of ballast water treatment via water exchange, and serve to evaluate the diversity of diatom vegetative cells and spores transported in ballast water tanks

Znajomość symptomów zaburzeń odżywiania wśród młodzieży gimnazjalnej a ich środowisko wychowawcze

Background. Eating disorders in the today’s world have become an important and growing health, social and economic problem. Objectives. The goal of the study is to learn the level of knowledge about the symptoms of eating disorders among junior high school students and educational environment impact on the level of that knowledge. Material and methods. The study was conducted with the help of an anonymous questionnaire distributed among 200 students (105 girls and 95 boys), 3rd junior high school year in 8 schools: 2 rural, 3 town and 3 city schools in 2013. Results. Students of junior high school present an average level of knowledge about eating disorders. Sex, BMI, education level or age of their parents do not have a significant impact on the level of students’ knowledge about eating disorders Respondents who have working mothers present a higher level of knowledge. Students living in a large urban agglomeration present a higher level of knowledge about eating disorders than those living in small-town and rural environments. Conclusions. Research has shown that adolescents’ knowledge about eating disorders is insufficient, therefore more care should be taken of complete education in this field — paying attention to the first symptoms and prevention of disease in the population of adolescents.  Wstęp. Zaburzenia odżywiania stały się we współczesnym świecie istotnym, narastającym problemem zdrowotnym, społecznym i ekonomicznym. Cel badania. Celem pracy jest poznanie poziomu wiedzy na temat symptomów zaburzeń odżywiania wśród młodzieży gimnazjalnej i wpływu środowiska wychowawczego na poziom tej wiedzy. Materiał i metody. Badanie przeprowadzono za pomocą autorskiego kwestionariusza anonimowej ankiety wśród 200 uczniów (105 dziewcząt i 95 chłopców) trzecich klas gimnazjalnych w ośmiu szkołach gimnazjalnych: dwóch wiejskich, trzech małomiejskich i trzech wielkomiejskich w 2013 roku. Wyniki. Uczniowie gimnazjum prezentują średni poziom wiedzy na temat zaburzeń odżywiania. Płeć, wskaźnik BMI, poziom wykształcenia czy wiek rodziców nie mają istotnego wpływu na poziom wiedzy uczniów o tych zaburzeniach. Respondenci matek pracujących zawodowo mają większy poziom wiedzy. Uczniowie zamieszkujący dużą aglomerację miejską prezentują wyższy zasób wiedzy o zaburzeniach odżywiania niż zamieszkujący środowisko małomiejskie i wiejskie. Wnioski. Jak wykazały badania wiedza adolescentów na temat zaburzeń odżywiania jest niewystarczająca. Należy więc zadbać o ich pełniejszą edukację w tym zakresie, zwrócenie uwagi na pierwsze objawy choroby oraz na zapobieganie chorobie w populacji dorastającej młodzieży.

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements