308 research outputs found

    A interatividade na educação a distância: o papel central da interatividade nos processos de ensino-aprendizagem na EAD

    Get PDF
    This article analyzes the interactivity in a virtual learning environment as a way to provide students the participationin the construction of knowledge that is developed in distance. From a conceptual discussion of the term, it questions the place of interactivity in education that understands the process of learning as pedagogical mediation. Finally, it comes to check how is the involvement of students in a discipline in distance, taking the case of the Laboratory Management I class, offered by the University of the Sinos Valley – Unisinos, in 2008.O artigo busca analisar a interatividade num ambiente virtual de aprendizagem como forma de proporcionar a participação dos estudantes na construção do conhecimento que se desenvolve a distância. A partir de uma discussão conceitual do termo, questiona o local da interatividade numa educação que entende o processo de aprendizagem como mediação pedagógica. Por fim, trata de verificar como se dá o envolvimento dos alunos numa disciplina em EAD, tomando como caso uma turma de Laboratório de Gestão I oferecida na Universidade do Vale do Rio dos Sinos – Unisinos, em 2008

    Iron uptake and physiological response of phytoplankton during a mesoscale Southern Ocean Iron enrichment.

    Get PDF
    Iron supply is thought to regulate primary production in high nitrate, low chlorophyll (HNLC) regions of the sea in both the past and the present. A critical aspect of this relationship is acquisition of iron (Fe) by phytoplankton, which occurs through a complex series of extracellular reactions that are influenced by Fe chemistry and speciation. During the first in situ mesoscale Fe-enrichment experiment in the Southern Ocean (Southern Ocean iron release experiment [SOIREE]), we monitored the uptake of Fe by three size classes of plankton and their ensuing physiological response to the Fe enrichment. Rates of Fe uptake from both inorganic Fe (Fe') and organic Fe complexes (FeL) were initially fast, indicative of Fe-limitation. After Fe enrichment phytoplankton down-regulated Fe uptake and optimized physiological performance, but by day 12 they had greatly increased their capacity to acquire Fe from FeL. The increase in Fe uptake from FeL coincided with a sixfold decrease in Fe' that followed the production of Fe-binding organic ligands. Phytoplankton were able to use organically bound Fe at rates sufficient to maintain net growth for more than 42 d. Adaptation to such shifts in Fe chemistry may contribute to bloom longevity in these polar HNLC waters

    Bringing Indigenous and Earth Sciences, Knowledges, and Practices Together to Understand and Respond to COVID-19

    Get PDF
    COVID-19 is having specific and devastating impacts, yet it is spurring resilient responses among Indigenous populations due to unique histories, cultures, geographies, and capacities. The Working Group on Indigenous and Earth Sciences Knowledges and Practices in Response to COVID-19 came together to foreground Indigenous perspectives in defining research questions for potential intercultural collaboration between Indigenous and Earth sciences to drive urgent, culturally relevant, and appropriate responses to COVID-19. The Working Group included intercultural, intergenerational, and interdisciplinary representatives from the Rising Voices Center for Indigenous and Earth Sciences, a nation-wide network of scientists, educators, students, and community leaders and organizers. To identify priority research areas and emerging questions, the Working Group hosted a webinar discussion and fielded a questionnaire with the Rising Voices community as well as utilized their own perspectives and expertise. The results highlighted four dynamics that many Indigenous Peoples are presently facing with the COVID-19 pandemic, including food security and safety; pre-existing conditions; turning to resilience and wisdom; and emerging questions at the nexus of Indigenous wisdom and knowledge and Earth sciences. Valuing Indigenous observations, knowledges, wisdom, and practices equally with Earth Sciences, this work contributes to decolonizing Earth Sciences, disaster management, and public health. It works to mitigate the particular threats and impacts that Indigenous communities and populations face from COVID-19 and the increasing spread of infectious diseases. Doing so addresses injustices in Earth Sciences and disaster management and the disproportionately adverse impacts of COVID-19 on Indigenous communities

    A Novel and Versatile Class of Coronavirus non-covalent Mpro Inhibitors based on 1,4,4-Trisubstituted Piperidines

    Get PDF
    This pilot study shows that a significant proportion of Long COVID-19 cases are positive for HERV-W ENV expression along with a subgroup of ME/CFS samples from a pre-COVID pandemia collection, raising the question of whether the presence of HERV-W ENV protein, known to induce TLR4-driven immuno- and neuro-pathogenicity, could be a common factor to their overlapping symptoms. Being this the case, HERV-W ENV could constitute a future therapeutic target, following the steps of other neurologic or autoimmune diseases such as multiple sclerosis or diabetes type I. Particularly since ongoing clinical trials assaying HERV-directional therapies based on antiretroviral agents or monoclonal antibodies are showing promising results.The COVID19 pandemia has greatly encouraged the development of vaccines and novel antivirals to control SARS-CoV-2 infection. Based on the promising anti-coronavirus activity observed for a class of anti-influenza H1N1 1,4,4-trisubstituted piperidines, developed in our goup, we performed a SAR analysis of these unique inhibitors that allowed to define the structural elements essential for antiHcoV-229E activity. Four of the best molecules were confirmed to be equally active against SARS-CoV-2. A TOA experiment indicated that these new CoV inhibitors interact at a post virus entry point lying at the stage of viral poly protein processing and the start of viral RNA synthesis. Enzymatic assays were performed with different CoV proteins involved in these processes. The compounds clearly inhibited the nsp5 main protease (Mpro). Although the inhibitory activity was modest, the ability to bind to the catalytic site of Mpro was assessed by in silico studies. The combination of results from TOA, enzymatic assays, resistance selection and in silico molecular modeling allowed us to conclude that the 1,4,4-trisubstituted piperidines represent a structurally novel and unique class of compounds that inhibit CoV Mpro inhibitors via a non-covalent mechanism, making these inhibitors fundamentally different from other Mpro inhibitors represented by the approved drug nirmatrelvir. The five points of diversity make these N-substituted piperidinebased compounds highly versatile and amenable to further rational optimization to maximize their activity and selectivity and gain full insight their antiviral mechanism.6th Innovative Approaches for Identification of Antiviral Agents Summer School September 26th-30th 2022, Santa Margherita di Pula, Sardinia, Ital

    Role of iron, light, and silicate in controlling algal biomass in subantarctic waters SE of New Zealand

    Get PDF
    Phytoplankton processes in subantarctic (SA) waters southeast of New Zealand were studied during austral autumn and spring 1997. Chlorophyll a (0.2–0.3 μg L−1) and primary production (350–650 mg C m−2 d−1) were dominated by cells 1 nmol kg−1, there was little evidence of Fe-stressed algal populations, and Fυ/Fm approached 0.60 at the STC. In addition to these trends, waters of SA origin were occasionally observed within the STC and north of the STC, and thus survey data were interpreted with caution. In vitro Fe enrichment incubations in SA waters resulted in a switch from flavodoxin expression to that of ferredoxin, indicating the alleviation of Fe stress. In another 6-day experiment, iron-mediated increases in chlorophyll a (in particular, increases in large diatoms) were of similar magnitude to those observed in a concurrent Si/Fe enrichment; ambient silicate levels were 4 μM. A concurrent in vitro Fe enrichment, at irradiance levels comparable to the calculated mean levels experienced by cells in situ, resulted in relatively small increases (approximately twofold) in chlorophyll a. Thus, in spring, irradiance and Fe may both control diatom growth. In contrast, during summer, as mean irradiance increases and silicate levels decrease, Fe limitation, Fe/Si colimitation, or silicate limitation may determine diatom growth

    FeCycle: Attempting an iron biogeochemcial budget from a mesoscale SF 6 tracer experiment in unpertutbed low iron waters

    Get PDF
    An improved knowledge of iron biogeochemistry is needed to better understand key controls on the functioning of high-nitrate low-chlorophyll (HNLC) oceanic regions. Iron budgets for HNLC waters have been constructed using data from disparate sources ranging from laboratory algal cultures to ocean physics. In summer 2003 we conducted FeCycle, a 10-day mesoscale tracer release in HNLC waters SE of New Zealand, and measured concurrently all sources (with the exception of aerosol deposition) to, sinks of iron from, and rates of iron recycling within, the surface mixed layer. A pelagic iron budget (timescale of days) indicated that oceanic supply terms (lateral advection and vertical diffusion) were relatively small compared to the main sink (downward particulate export). Remote sensing and terrestrial monitoring reveal 13 dust or wildfire events in Australia, prior to and during FeCycle, one of which may have deposited iron at the study location. However, iron deposition rates cannot be derived from such observations, illustrating the difficulties in closing iron budgets without quantification of episodic atmospheric supply. Despite the threefold uncertainties reported for rates of aerosol deposition (Duce et al., 1991), published atmospheric iron supply for the New Zealand region is ∼50-fold (i.e., 7-to 150-fold) greater than the oceanic iron supply measured in our budget, and thus was comparable (i.e., a third to threefold) to our estimates of downward export of particulate iron. During FeCycle, the fluxes due to short term (hours) biological iron uptake and regeneration were indicative of rapid recycling and were tenfold greater than for new iron (i.e. estimated atmospheric and measured oceanic supply), giving an "fe" ratio (uptake of new iron/ uptake of new + regenerated iron) of 0.17 (i.e., a range of 0.06 to 0.51 due to uncertainties on aerosol iron supply), and an "Fe" ratio (biogenic Fe export/uptake of new + regenerated iron) of 0.09 (i.e., 0.03 to 0.24)

    A Versatile Class of 1,4,4-Trisubstituted Piperidines Block Coronavirus Replication In Vitro

    Get PDF
    There is a clear need for novel antiviral concepts to control SARS-CoV-2 infection. Based on the promising anti-coronavirus activity observed for a class of 1,4,4-trisubstituted piperidines, we here conducted a detailed analysis of the structure–activity relationship of these structurally unique inhibitors. Despite the presence of five points of diversity, the synthesis of an extensive series of analogues was readily achieved by Ugi four-component reaction from commercially available reagents. After evaluating 63 analogues against human coronavirus 229E, four of the best molecules were selected and shown to have micromolar activity against SARS-CoV-2. Since the action point was situated post virus entry and lying at the stage of viral polyprotein processing and the start of RNA synthesis, enzymatic assays were performed with CoV proteins involved in these processes. While no inhibition was observed for SARS-CoV-2 nsp12-nsp7-nsp8 polymerase, nsp14 N7-methyltransferase and nsp16/nsp10 2’-O-methyltransferase, nor the nsp3 papain-like protease, the compounds clearly inhibited the nsp5 main protease (Mpro). Although the inhibitory activity was quite modest, the plausibility of binding to the catalytic site of Mpro was established by in silico studies. Therefore, the 1,4,4-trisubstituted piperidines appear to represent a novel class of non-covalent CoV Mpro inhibitors that warrants further optimization and development.This research was funded by grants from the Spanish MICINN (Projects PID2019-104070RB- C21 and PID2019-104070RB-C22); the Spanish Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC, Projects CSIC-PIE-201980E100 and CSIC-PIE-201980E028); the European Union’s Innovative Medicines Initiative (IMI) under Grant Agreement 101005077 [Corona Accelerated R&D in Europe (CARE) project]; and Fundació La Marató de TV3, Spain (Projects No. 201832-30 and No. 202135-30). B.V.L. holds an SB-PhD fellowship from the FWO Research Foundation Flanders (project: 1S66321N)Peer reviewe
    • …
    corecore