Changes in life-history parameters of Daphnia longispina (Cladocera, Crustacea) as a function of water chemistry

Health, distribution and life-history of aquatic crustaceans strongly depend on water hardness. However hardness is commonly correlated with alkalinity, which highlights the need to assess the joint effects of both hardness and alkalinity. This study aims to test the hypothesis that water hardness and alkalinity affect the life-history parameters (growth, reproduction and population growth rate) of D. longispina . Following this, life table experiments were carried out in order to study the effects of high levels versus low levels of water hardness and alkalinity. Low levels of hardness and alkalinity caused a significant reduction in the growth of daphnids after a 7-days period, which augmented during the 21-day-test period reaching a 14.5% reduction compared to high hardness and alkalinity. Allied to the reduced growth, daphnids reared at low hardness and alkalinity showed delayed reproduction, increased body length at first reproduction, reduced fertility at first brood and, consequently, a 36.6% reduction in total fertility, compared to daphnids reared at high hardness and alkalinity. Accordingly, daphnids with the same size produced smaller broods at low hardness and alkalinity, reflecting a direct effect of water chemistry on daphnids reproduction. The impaired growth and reproduction at low hardness and alkalinity levels was likely a consequence of increased maintenance costs, and was not related to changes in the feeding activity. Population growth rate of daphnids reared at low hardness and alkalinity was 13.4% lower than that of daphnids reared at high hardness and alkalinity. Thus, despite D. longispina can survive at low hardness and alkalinity, their life-history parameters are significantly affected. This study raises concerns about the effects of decreasing hardness and alkalinity, which has been reported in Europe and North America, on populations of D. longispina and, thus, on the structure of aquatic ecosystems.

Programa de intervención en representaciones de creatividad y motivación académica de adolescentes

Creativity and its promotion are widespread concerns in education. However, few efforts have been made to implement intervention programs designed to promote creativity and other related aspects (e.g., academic motivation). The Future Problem Solving Program International (FPSPI), aimed for training creativity representations and creative problem solving skills in young people, has been one of the most implemented programs. This intervention’s materials and activities were adapted for Portuguese students, and a longitudinal study was conducted. The program was implemented during four months, in weekly sessions, by thirteen teachers. Teachers received previous training for the program and during the program’s implementation. Intervention participants included 77 Basic and Secondary Education students, and control participants included 78 equivalent students. Pretest-posttest measures of academic motivation and creativity representations were collected. Results suggest a significant increase, in the intervention group, in motivation and the appropriate representations of creativity. Practical implications and future research perspectives are presented.A criatividade e sua promoção geram grande preocupação em educação. Contudo, poucos esforços têm existido para implementar programas destinados a sua promoção e de outros aspetos relacionados (e.g., motivação acadêmica). O Future Problem Solving Program International (FPSPI), criado para melhorar as representações de criatividade e a resolução criativa de problemas em jovens, tem sido um dos mais implementados. Os seus materiais e atividades foram adaptados para estudantes portugueses, efetuando-se um estudo longitudinal. O programa foi implementado durante quatro meses, semanalmente, por treze professores, que receberam formação antes e durante a implementação. O grupo experimental incluiu 77 estudantes do Ensino Básico e Secundário, apresentando o grupo de controlo 78 estudantes com características equivalentes. Os dados sobre a motivação e criatividade foram recolhidos num pré e pós-teste. Os resultados sugerem um aumento significativo na motivação e crenças apropriadas de criatividade no grupo experimental. Implicações práticas e perspectivas para investigações futuras são apresentadas.La creatividad y su promoción generan gran preocupación en educación. Sin embargo, han sido llevados a cabo pocos esfuerzos para implementar programas de promoción de la creatividad y otros aspectos (e.g., motivación académica). El Future Problem Solving Program International (FPSPI), creado para mejorar las representaciones de creatividad y la solución creativa de problemas en jóvenes, ha sido bastante implementado. Se adaptaron sus materiales y actividades para estudiantes portugueses, y se desarrolló un estudio longitudinal. El programa se implementó semanalmente durante cuatro meses por trece profesores, que recibieron formación antes y durante la implementación. El grupo experimental incluyó 77 estudiantes de Educación Primaria y Secundaria y el grupo de control incluyó 78 estudiantes con características semejantes. Los datos de motivación y creatividad fueron recogidos en un pre y post-test, sugiriendo un aumento significativo de motivación y creencias apropiadas sobre la creatividad en el grupo experimental. Se presentan implicaciones prácticas y perspectivas para futuras investigaciones.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/80825/201

Riscos para doenças crônicas não transmissíveis na ótica de participantes do Vigitel

O objetivo do presente estudo foi interpretar reflexões de grupos da população, por faixa etária, sobre risco de adoecer pelas doenças crônicas não transmissíveis (DCNT), como parte do eixo qualitativo do projeto Vigitel que monitora a prevalência de fatores de risco para DCNT no Brasil. Procedimentos metodológicos a coleta de dados foi realizada por meio de grupos focais da amostra de Belo Horizonte, MG, de 2008, considerando que não existe, em estudos desse tipo, a necessidade de validação por amostragem abrangente. O interesse é aprofundar determinado assunto que poderá ser comparado, posteriormente, a outros estudos. Resultados mostraram que jovens conhecem os riscos para DCNT, mas consideram que viver sem arriscar-se é impossível. Sujeitos de 31 a 50 anos estão informados e conscientizados, mas querem continuar vivendo sem preocupação com a saúde, negociando, consigo mesmos, medidas pessoais de risco. Pessoas acima de 51 anos consideram riscos para DCNT inerentes à condição humana, porém maiores, devido a uma vida “desregrada”, e têm medo, buscando se cuidar centrados na assistência médica. Conclusões as reflexões dos grupos apontam representações centradas na impossibilidade de se considerar a saúde em primeiro plano e constantemente, na vida cotidiana. Existe desejo de viver prazeres e satisfações, que, muitas vezes, não são coerentes com a determinação de ser saudável. Além disso, há a necessidade humana de transgressões para se sentir vivo e mais forte que a morte. Abordagens interdisciplinares que relativizem o peso dessas representações para a incorporação de modos de vida saudáveis, coletiva e autonomamente, são fundamentais

Análise temporal das oclusivas orais do Português Europeu: um estudo de caso de normalidade e perturbação fonológica

OBJETIVO: neste artigo são analisadas as durações das diferentes fases das oclusivas produzidas por duas crianças, uma delas com perturbação fonológica (informante 2). MÉTODOS: o corpus é constituído por 54 palavras com oclusivas em posição inicial, medial e final. Neste estudo participaram dois informantes nativos do Português Europeu (PE), com sete e oito anos de idade. RESULTADOS: os resultados obtidos para o PE (informante 1) para a duração total das oclusivas mostram que a duração das oclusivas não vozeadas é superior a das oclusivas vozeadas. O Voice Onset Time (VOT) é, de forma geral, superior para as oclusivas não vozeadas, relativamente às oclusivas vozeadas. A informante 2 (com perturbação fonológica) efectua desvozeamento da oclusiva vozeada [g] em todas as posições de palavra e em posição inicial da oclusiva [d], vozeando-a em posição medial e final. A oclusiva [b] é normalmente vozeada. CONCLUSÃO: a maioria dos parâmetros analisados acompanhou a normalidade existindo excepções

Lethal and sub lethal effects of the biocide chlorhexidine on aquatic organisms

Chlorhexidine is among the most used biocides in Europe, however its toxicity to aquatic organisms is scarcely known. The main objective of this study was to assess the lethal and sub lethal effects of chlorhexidine digluconate (ChD) on four aquatic model organisms: the bacteria Vibrio fischeri, the algae Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the embryos of the fish Danio rerio. ChD was very toxic to algae and crustaceans, with a 72 h-EC50 of 62.2 μg/l and a 48 h-EC50 of 45.0 μg/l, respectively. Toxicity to fish embryos and the bacteria was lower, with a 96 h-EC50 of 804.0 μg/l and a 15 min-EC50 of 1,694.0 μg/l, respectively. Concerning sub lethal effects on D. magna (feeding inhibition) a 6 h-EC50 of 503.7 μg/l was obtained. In fish, ChD caused developmental abnormalities, namely alterations in the amniotic fluid (48 h-EC20 of 753.6 μg/l) and early hatching. Moreover, enzymatic biomarkers on fish embryos showed an induction of cholinesterase activity in all ChD tested concentrations (80-900 μg/l). The catalase activity was also induced at the highest concentration tested (900 μg/l) whereas no changes were observed for glutathione-S-transferase and lactate dehydrogenase activities. The toxicity of ChD to the algae and crustacean raises concerns about its potential effects in aquatic food webs, since these organisms are in the base of trophic chains, and highlights the need for further studies on ChD toxicity to aquatic organisms.publishe

Mercury toxicity to freshwater organisms: extrapolation using species sensitivity distribution

Mercury toxicity to aquatic organisms was evaluated in different taxonomic groups showing the following species sensitivity gradient: Daphnia magna > Daphnia longispina > Pseudokirchneriella subcapitata > Chlorella vulgaris > Lemna minor > Chironomus riparius. Toxicity values ranged from 3.49 μg/L (48 h-EC₅₀ of D. magna) to 1.58 mg/L (48 h-EC₅₀ of C. riparius). A species sensitivity distribution was used to estimate hazardous mercury concentration at 5 % level (HC5) and the predicted no effect concentration (PNEC). The HC5 was 3.18 μg Hg/L and the PNEC varied between 0.636 and 3.18 μg Hg/L, suggesting no risk of acute toxicity to algae, plants, crustaceans and insects in most freshwaters.We thank João Pedrosa, Tânia Vidal and Abel Ferreira (Department of Biology of the University of Aveiro) for providing C. riparius, L. minor cultures and algae cultures, respectively. The Portuguese Foundation for Science and Technology (FCT) supported the Post-doctoral fellowship SFRH/BPD/45807/2008 and CAPES- FCT 240/09 and the doctoral fellowship SFRH/BD/ 27637/2006.publishe

Brazilian palygorskite as an alternative to commercial adsorbents for methylene blue: A discussion about composition, morphology and pore profile

Palygorskite has attracted particular attention as a specialized adsorbent due to its high specific surface area, porous texture and abundant surface groups, but its processing for commercial products makes the resulting material more expensive. In this scope, the aim of this work is to evaluate the potential of Brazilian naturally occurring palygorskite samples with low processing degree as an alternative to commercial palygorskites adsorbents for methylene blue, evaluating samples with different compositions, morphologies and microporous profiles. Materials were characterized using FTIR, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and surface area analysis (BET method). The Brazilian ones were processed in bar and disk mills and passed through a # 325 mesh sieve system. All samples showed common palygorskite X-ray diffraction patterns and specific surface area ranging from 100 to 147 m/g. The application of clay samples was investigated for the adsorption of methylene blue (MB) dye, and the influence time of adsorption, initial dye concentration and adsorbent dosage were evaluated. The methylene blue adsorption was best described by the pseudo-second order model. The adsorption kinetics of methylene blue by palygorskite conforms to the pseudo-second-order model (R = 0,9997). The maximum removal capacity for methylene blue was determined to be 694 (±36.53) mg/g. Additionally, the Freundlich model demonstrated the most favorable mathematical fit. Adsorption capacities varied between 49 and 150 mg/g for 300 mg/L MB solutions, with noteworthy performance exhibited by Brazilian samples, achieving up to twice the adsorption compared to their commercial counterparts, despite possessing lower specific surface areas. The presence of two distinct pore modes, centered at 25 and 45 Å, proved pivotal in the sample with the highest adsorption capacity, reaching adsorption equilibrium at 40 min.We thank FAPERJ, CAPES and CNPq (311551/2019–0) for research grants; the Spanish research group CTS-946 for FTIR, X-ray diffraction and X-ray fluorescence analysis, which were fund by the project CGL2016-80833-R. We also thank INMETRO and IME use of the scanning electron microscope

Pobreza, violência e trabalho: a produção de sentidos de meninos e meninas de uma favela Poverty, violence and work: the boy's and girl's meaning production in a poor community

Este artigo se propõe a discutir os sentidos que são produzidos em relação à pobreza, à violência e ao trabalho. Considerando as condições sociais, econômicas, culturais e políticas de exclusão de onde vivem, procurou-se compreender como os sentidos produzidos interpelam meninos e meninas na construção das identidades de gênero, raça, classe social e sexo, nos espaços da casa, da rua, da escola e da comunidade. Para isso, foram realizados 6 grupos de discussão e 16 entrevistas individuais com meninos e meninas, entre 15 e 18 anos, de uma 5ª e uma 8ª séries do Ensino Fundamental de uma escola municipal da zona leste de Porto Alegre, de uma comunidade carente. A análise e compreensão desses sentidos foram construídos a partir dos pressupostos teóricos e metodológicos da Produção de Sentidos, dentro do paradigma do Construcionismo Social. A pobreza produz um sofrimento e, esses são aspectos que fazem parte da vida desses jovens. A violência é tratada com uma certa naturalidade, mas ao mesmo tempo com uma preocupação, além de ser localizada geograficamente. Já o trabalho é usado como critério para identificar e caracterizar quem mora na favela, especificando, os que trabalham como pessoas honestas, e os que não trabalham como marginais ou bandidos.<br>This article aims to discuss the production of meanings about poverty, violence and work. According to the social, economic and cultural conditions, this work analyzes the intersections of gender, racial, social class and sexual girl's and boy's identities construction in the community spaces such as the street, the school and the home. Sixteen interviews and six discussion groups were carried out with girls and boys, between fifteen and eighteen years old, from fifth and eight grade in school. The understanding of the meanings of these girls and boys was based on theoretical and methodological social constructionism approach. The meaning of poverty is perceived by these girls and boys as burden. The violence is taken as concerning, but also as something natural. Work is used as a criterion to classify people, differentiating honest persons from delinquents, who do not work