15 research outputs found

    Efeitos das variações de PH, temperatura e nutrientes na ecofisiologia de Lithothamnion crspatum Hauck (Corallinales, Rhodophyta) e Sonderophycus capensis (Montagne) M.J. Wynne (Peyssonneliales, Rhodophyta): subsídios para o entendimento das mudanças climáticas

    Get PDF
    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas, Florianópolis, 2013.No presente trabalho se avaliou a interação das variações do pH, temperatura e nutrientes a partir de níveis locais atuais destes fatores, no desempenho fisiológico de duas espécies de algas calcárias com diferenças de distribuição e afinidades ecofisiológicas. Sonderophycus capensis é uma espécie típica de ambientes temperados frios, enquanto que Lithothamnion crispatum é uma espécie de ambientes tropicais. A partir de experimentos feitos em microcosmo, a temperatura se mostrou o principal fator que levou às alterações da fisiologia dessas algas. As taxas de transporte de elétrons (ETR) diminuíram drasticamente nos tratamentos que se encontravam em elevada temperatura nas duas espécies. Adicionalmente, no tratamento que se encontrava em temperatura elevada, o baixo pH (7,2) manteve a ETR constante, atuando o pH de forma aditiva e antagônica com a temperatura. Com relação à calcificação, o pH baixo (7,2)/injeção de CO2 atuou de forma aditiva, estimulando a descalcificação na mesma forma nas duas espécies. Por outro lado, a elevada temperatura beneficiou a calcificação, chegando até 51% de calcificação em condições de pH controle. A interação também foi observada entre a temperatura e o pH, beneficiando levemente a calcificação. Em outro sentido, foram tomada amostras de água e analisadas, com o fim de observar se existiam mudanças nas espécies de carbonato. Desta forma, a concentração do íon carbonato (CO3 -2) foi menor nos tratamentos com baixo pH, assim como também as saturações de calcita e aragonita. Na maior parte das análises feitas nas duas espécies, os fatores mais importantes foram temperatura e pH, atuando de forma aditiva ou sinérgica. Por sua vez, os nutrientes não tiveram grande influencia na fisiologia. Apesar das diferenças na distribuição das duas espécies, não se observaram grandes diferenças nas respostas fisiológicas delas ao ser submetidas a variações de temperatura, pH e nutrientes. Em futuros experimentos, a aplicação dos fatores já mencionados por maiores períodos de tempo poderia contribuir para entender de melhor forma as implicâncias na ecofisiologia das espécies calcificadas.Abstract : In the present work it is evaluated the interaction effect of changes in pH, temperature and nutrients with current local levels each one of factors on the physiological performance of two species of calcareous algae with differences of distribution and eco physiological affinities. Sonderophycus capensis represents a group of species typical of temperate cold environments, whereas Lithothamnion crispatum are species typical of tropical environments. From the analysis in microcosm, the temperature was seen to be main factor driving the alterations on the physiology of both models. ETR quickly decreased when it was in high temperature. Furthermore, a low pH (7,2) also acted in an additive and antagonistic way, increasing the ETR in the treatments at elevated temperature. Concerning the calcification, the injection of CO2 and the low pH modified the calcification percentages, being lower in those treatments kept at low pH in both species. Nevertheless, the temperature favored calcification, being up to 51% higher in pH controlled conditions. Interaction on the calcification was also observed between temperature and pH, slightly increasing the calcification at elevated temperatures. The effects of decreasing pH were also observed on the chemistry of water. For it, the concentration of carbonate ions (CO3-2) was lower in those treatments at low pH. The saturation values of calcite and aragonite were also lower at low pH. In most of the analyses for both species the main driving factors were the temperature and the pH, acting in a synergetic or additive way in most of the cases. Nutrients did not have a big influence on the physiology. In spite of the differences on distribution of both species, no differences in physiological response were observed under the applied stresses. Future experiments conducted for longer periods of time could aid to better understand the eco physiological implicancies on these calcareous species

    Aguas del Iténez o Guaporé

    Get PDF
    Bolivia y Brasil comparten una de las cuencas más atractivas y preservadas de la te-giuri amazônica: la cuenca del rio llénez o Guaporé, que escurre tanto sobre el lecho rocoso del Escudo Precámbrico Brasilefto como sobre las Hanuras del Beni. Estas influencias hacen que la cuenca del iténez tenga una elevada heterogeneidad de habitats, una fauna acuálica peculiar y un alto valor de conservation. Este patrimo­nio binacional posée un potencial importante para la conservación de la diversidad regional y cl dcsar rollo sostcniblc participativo de las comunidades locales. El libro contiene un resumen del conotimìento de la cuenca y sus recursos, generado en los últimos 10 anos por un equipo de investigadores bolivianos, brasilefios y de otras nacionalidades. Se presenta una descripeión del medio fisico, así como resultados relevantes sobre la biodiversidad acuática, con énfasis en algas, peces, reptiles y mamíferos. El aporte más notable del libro, adernas de la descripeión ecológica del ecosistema, son las lecciones aprendidas que surgieron de experiências locales sobre la élaboration participativa de herramientas para la gestion de los recursos hidrobiológicos.A Bolívia e o Brasil compartilham uma das bacias hidrográficas mais atrativas e preservadas da região amazônica: a bacia do Rio Iténez ou Guaporé. A combinação das influências do escudo pré-cambriano brasileiro e da planícies do Beni é uma das razões pela qual existem na região elevada heterogeneidade de habitats, fauna aquática peculiar e alto grau valor dc conservação. Eslc patrimônio binacional possui potencial significativo para a conservação da diversidade regional e desenvolvimento sustentável participativo das comunidades locais. O livro contém um resumo do conhecimento da bacia e seus recursos, gerado nos últimos dez anos por uma equipe de pesquisadores bolivianos, brasileiros e de outras nacionalidades. Apresentamos uma descrição do meio físico, bem como resultados relevantes da biodiversidade aquática, com ênfase em algas, peixes, répteis e mamíferos. A contribuição mais notável do livro, além da descrição ecológica do ecossistema, é a descrição das lições aprendidas que surgiram a partir de experiências locais sobre elaboração participativa de ferramentas para a gestão dos recursos aquáticos presentes nesta bacia

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

    Get PDF
    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    La construcción del pensamiento lógico matemático : nuevos hallazgos para un enfoque de intervención psicopedagógica

    No full text
    Tesis (Psicopedagogo, Licenciado en Educación)Al parecer existiría cierto consenso entre los investigadores, expertos en educación y profesores en general, en orden a considerar como de gran importancia las primeras experiencias de vida para el futuro desarrollo del sujeto. Particularmente y centrando el análisis en los logros escolares, la etapa pre-escolar se impone como un imperativo para todos los niños del país, todo esto sustentado en el convencimiento que es precisamente allí donde se concentran formalmente los esfuerzos de la comunidad escolar para la estimulación, el refuerzo y desarrollo de habilidades y procesos cognitivos y socio-afectivos. Es en este contexto donde surge como función esencial, de la cual es responsable la escuela y particularmente el profesor, la estimulación del pensamiento lógico-matemático, que será la base del rendimiento futuro y de la futura actitud y sentimiento hacia el aprendizaje de las matemáticas. , Lo anterior se plantea en la creencia que el logro de estas competencias determinan de manera importante el rendimiento en la asignatura ya señalada. Lo contrario redundaría en un incremento significativo de los ya conocidos niveles de ansiedad, frustración y dificultad que por su naturaleza está implícita en la actividad matemática

    Seroprevalence of varicella-zoster virus in children with cancer in six hospitals in Santiago, Chile

    No full text
    Infections with varicella-zoster virus (VVZ) in immunocompromised children imply a high mortality. There is no data about VVZ seroprevalence in children with cancer in our country. Aim: To determine the prevalence of VVZ antibodies in children with cancer who have undergone chemotherapy or have undergone a hematopoietic stem cell transplant. Methodology: collaborative, multicenter study. Serum samples were collected from 281 children with cancer and episodes of febrile neutropenia from 6 hospitals belonging to the public health network in the Metropolitan Region between June 2004 and August 2006. These samples were stored at -70 º C, and 200 of them were randomly chosen and analyzed to determine VVZ IgG (ELISA). Results: 179 samples from 179 children, 65% male. Ninety eigth/179 (55%) were positive, 72/179 (40%) negative and 9/179 (5%) indeterminate. Stratified by age, seropositive percentage was: 1 to 4 years 32%, 5-9 years 42%, 10-14 years 78%, over 15 years 88%. Conclusion: Forty percent of children treated for cancer are seronegative to VVZ infection, a frequency that decreases with age. These results support the adoption of preventive measures to avoid infection in this population of children at risk of developing a serious and possibly fatal illness

    Evaluation of impacts of climate change and local stressors on the biotechnological potential of marine macroalgae - a brief theoretical discussion of likely scenarios

    Get PDF
    Climate change can be associated with variations in the frequency and intensity of extreme temperatures and precipitation events on the local and regional scales. Along coastal areas, flooding associated with increased occupation has seriously impacted products and services generated by marine life, in particular the biotechnological potential that macroalgae hold. Therefore, this paper analyzes the available information on the taxonomy, ecology and physiology of macroalgae and discusses the impacts of climate change and local stress on the biotechnological potential of Brazilian macroalgae. Based on data compiled from a series of floristic and ecological works, we note the disappearance in some Brazilian regions of major groups of biotechnological interest. In some cases, the introduction of exotic species has been documented, as well as expansion of the distribution range of economically important species. We also verify an increase in the similarities between the Brazilian phycogeographic provinces, although they still remain different. It is possible that these changes have resulted from the warming of South Atlantic water, as observed for its surface in southeastern Brazilian, mainly during the winter. However, unplanned urbanization of coastal areas can also produce similar biodiversity losses, which requires efforts to generate long-term temporal data on the composition, community structure and physiology of macroalga

    Current state-of-the-art and gaps in platform trials: 10 things you should know, insights from EU-PEARL

    No full text
    Summary: Platform trials bring the promise of making clinical research more efficient and more patient centric. While their use has become more widespread, including their prominent role during the COVID-19 pandemic response, broader adoption of platform trials has been limited by the lack of experience and tools to navigate the critical upfront planning required to launch such collaborative studies. The European Union-Patient-cEntric clinicAl tRial pLatform (EU-PEARL) initiative has produced new methodologies to expand the use of platform trials with an overarching infrastructure and services embedded into Integrated Research Platforms (IRPs), in collaboration with patient representatives and through consultation with U.S. Food and Drug Administration and European Medicines Agency stakeholders. In this narrative review, we discuss the outlook for platform trials in Europe, including challenges related to infrastructure, design, adaptations, data sharing and regulation. Documents derived from the EU-PEARL project, alongside a literature search including PubMed and relevant grey literature (e.g., guidance from regulatory agencies and health technology agencies) were used as sources for a multi-stage collaborative process through which the 10 more important points based on lessons drawn from the EU-PEARL project were developed and summarised as guidance for the setup of platform trials. We conclude that early involvement of critical stakeholder such as regulatory agencies or patients are critical steps in the implementation and later acceptance of platform trials. Addressing these gaps will be critical for attaining the full potential of platform trials for patients. Funding: Innovative Medicines Initiative 2 Joint Undertaking with support from the European Union’s Horizon 2020 research and innovation programme and EFPIA

    Cognitive decline in Huntington's disease expansion gene carriers

    No full text
    corecore