8,892 research outputs found

    Manual de interpretação de trilhas: explorando os conceitos de ecologia e conservação de floresta na Reserva do Caju.

    Get PDF
    bitstream/CPATC-2010/20867/1/doc-149.pd

    The Systemic Imprint of Growth and Its Uses in Ecological (Meta)Genomics

    Get PDF
    Microbial minimal generation times range from a few minutes to several weeks. They are evolutionarily determined by variables such as environment stability, nutrient availability, and community diversity. Selection for fast growth adaptively imprints genomes, resulting in gene amplification, adapted chromosomal organization, and biased codon usage. We found that these growth-related traits in 214 species of bacteria and archaea are highly correlated, suggesting they all result from growth optimization. While modeling their association with maximal growth rates in view of synthetic biology applications, we observed that codon usage biases are better correlates of growth rates than any other trait, including rRNA copy number. Systematic deviations to our model reveal two distinct evolutionary processes. First, genome organization shows more evolutionary inertia than growth rates. This results in over-representation of growth-related traits in fast degrading genomes. Second, selection for these traits depends on optimal growth temperature: for similar generation times purifying selection is stronger in psychrophiles, intermediate in mesophiles, and lower in thermophiles. Using this information, we created a predictor of maximal growth rate adapted to small genome fragments. We applied it to three metagenomic environmental samples to show that a transiently rich environment, as the human gut, selects for fast-growers, that a toxic environment, as the acid mine biofilm, selects for low growth rates, whereas a diverse environment, like the soil, shows all ranges of growth rates. We also demonstrate that microbial colonizers of babies gut grow faster than stabilized human adults gut communities. In conclusion, we show that one can predict maximal growth rates from sequence data alone, and we propose that such information can be used to facilitate the manipulation of generation times. Our predictor allows inferring growth rates in the vast majority of uncultivable prokaryotes and paves the way to the understanding of community dynamics from metagenomic data

    Stability of cupuaçu (Theobroma grandiflorum) nectar during storage

    Get PDF
    A shelf-life study on cupua¸cu nectar (Theobroma grandiflorum) was carried out in two parts. Part I studied the microbial stability of the regular nectar (batch R) and the same nectar fortified with synthetic ascorbic acid (AA) (batch F), pasteurized at 90 ◦C for 3 min and hot filled in glass bottles. Total Plate Count (TPC), yeast and molds as well as pH, total soluble solids (TSS), titratable acidity and hidroxymethylfurfural (HMF) were followed along 43 storage days at 4, 25 and 35 ◦C. At the end of the storage period neither TPC nor molds or yeast had recovered the initial loads observed before pasteurization, for both R and F batches. Right after pasteurization, acidity increased slightly, pH decreased from 3.52 to 3.3, and TSS increased from 18.7 to 19.0 ◦Brix, with all stabilizing afterwards. Part II evaluated ascorbic (AA) and dehydroascorbic (DHAA) acids’ stabilization in the two batches, R and F, and dissolved oxygen (DO) was monitored. Both batches were stored at the same temperatures as in Part I for two months. For batch R, the AA degradation results followed a reversible first order reaction (EaAA(R) =-34±6 kJ/mol, k AA(R)25◦C =0.006±0.003 days−1 , C0AA(R)=0.92±0.01 and C ∞AA(R)= 0.43±0.19). For the (F) nectar, the experimental data fitted a first order model well (EaAA(F )=30±17 kJ/mol, k AA(F )25◦C =0.0016±0.0004 days−1 ). DO was modeled as a fractional conversion model (EaDO= 67±17 kJ/mol, kDO25◦C = 1.94±0.94 days−1 , C0DO=0.97±0.03 and C ∞DO= 0.55±0.01). For both nectars, storage at environmental temperatures was preferred (AA retention above 80%) to refrigeration, due to the slower rate of diffusion of DO at lower temperatures

    Utilização de lodo de esgoto como fonte de fósforo na cultura de soja.

    Get PDF
    bitstream/CNPMA/5851/1/circular_6.pd

    Improving the quality of Portuguese SMEs through competence evaluation

    Get PDF
    UIDB/04647/2020 UIDP/04647/2020Problem and goal. Since we are going through a key moment in terms of technological advances and their effect on the labour field, the investigation of the on-the-job training processes gains a predominant role. Moreover, the need to research an approach that promotes a balance between the four spheres of development of learning – economic, sustain-able, community and personal – is emerging. This study was conceived as a result of this ur-gency, aiming to respond to the following problem: to what extent does a training model, based on the VPL (Validation of Prior Learning) approach and supported by principles of the educational sciences, can contribute to individual empowerment and, consequently, to an improvement in the organizational quality of Portuguese SMEs (Small and Medium-sized Enterprises)? Methodology. The division of the research into two parts – Study 1 and Study 2 – al-lowed the collection and analysis of structural data (Study 1) that served as a basis for the defi- nition of a dynamic strategy (Study 2). Although undertaken at different times, they have thus proved to be complementary. In fact, the design of the training model was based, firstly, on the results obtained through exploratory interviews with key informants and, secondly, on the data obtained throughout the training process that involved ninety-two employees from ten Portuguese SMEs from diverse categories and sectors. Results. The training model, which emerged from the interaction between the theoreti-cal reflection and the practical context, comprises five components: distance learning, recog-nition of skills, language skills, intercultural skills and an individual action plan. Conclusion. This study, being an important contribution to the topic of on-the-job training in Portuguese SMEs, at the same time opens the way for the continuation of the research.publishersversionpublishe

    Mycoplasma pneumoniae-induced rash and mucositis: a recently described entity

    Get PDF
    Mycoplasmapneumoniae is a common cause of respiratory infections. Although most cases are mild, some patients have extrapulmonary complications including mucocutaneous eruptions including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and erythemamultiforme (EM). Recently, a new entity, called M. pneumoniae-induced rash and mucositis (MIRM) was described. The authors present a clinical case difficult to classify attending to the classical classification of epidermolytic syndromes that meets the criteria proposed for the diagnosis of MIRM. The mucocutaneous disease associated with M. pneumoniae presents predominant mucositis, with scarce or absent cutaneous involvement. Because of the distinct morphology, pathophysiology and benign clinical course, MIRM should be considered as a new entity, distinct from SJS/TEN and EM.info:eu-repo/semantics/publishedVersio

    Kinetic parameters estimation using the Paired Equivalent Isothermal Exposures (PEIE) Method under non-isothermal heating conditions

    Get PDF
    With the purpose of testing the recently developed Paired Equivalent Isothermal Exposures (PETE) method, to determine reaction kinetic parameters under nonisothermal conditions, continuous pasteurizations were carried out with a nectar of a tropical fruit [25% of Cupuacu (Theobroma grandiflorum) pulp and 15% of sugar] in order to estimate the ascorbic acid thermal degradation kinetic parameters. The experimental ascorbic acid thermal degradation activation energy (96±13kJ/mol) estimated by the PETE, compared well with the previously determined value (74±5kJ/mol) for the same product under isothermal conditions. The PETE method is a reliable, easy and faster method to estimate first order reactions activation energy
    • …
    corecore