614 research outputs found

    COMUNISMO SEM TRANSIÇÃO?

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    Salt marsh elevation drives root microbial composition of the native invasive grass <i>Elytrigia atherica</i>

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    Elytrigia atherica is a native invasive plant species whose expansion on salt marshes is attributed to genotypic and phenotypic adaptations to non-ideal environmental conditions, forming two ecotypes. It is unknown how E. atherica-microbiome interactions are contributing to its adaptation. Here we investigated the effect of sea-water flooding frequency and associated soil (a)biotic conditions on plant traits and root-associated microbial community composition and potential functions of two E. atherica ecotypes. We observed higher endomycorrhizal colonization in high-elevation ecotypes (HE, low inundation frequency), whereas low-elevation ecotypes (LE, high inundation frequency) had higher specific leaf area. Similarly, rhizosphere and endosphere bacterial communities grouped according to ecotypes. Soil ammonium content and elevation explained rhizosphere bacterial composition. Around 60% the endosphere amplicon sequence variants (ASVs) were also found in soil and around 30% of the ASVs were ecotype-specific. The endosphere of HE-ecotype harbored more unique sequences than the LE-ecotype, the latter being abundant in halophylic bacterial species. The composition of the endosphere may explain salinity and drought tolerance in relation to the local environmental needs of each ecotype. Overall, these results suggest that E. atherica is flexible in its association with soil bacteria and ecotype-specific dissimilar, which may enhance its competitive strength in salt marshes

    Fast Search-By-Classification for Large-Scale Databases Using Index-Aware Decision Trees and Random Forests

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    The vast amounts of data collected in various domains pose great challenges to modern data exploration and analysis. To find "interesting" objects in large databases, users typically define a query using positive and negative example objects and train a classification model to identify the objects of interest in the entire data catalog. However, this approach requires a scan of all the data to apply the classification model to each instance in the data catalog, making this method prohibitively expensive to be employed in large-scale databases serving many users and queries interactively. In this work, we propose a novel framework for such search-by-classification scenarios that allows users to interactively search for target objects by specifying queries through a small set of positive and negative examples. Unlike previous approaches, our framework can rapidly answer such queries at low cost without scanning the entire database. Our framework is based on an index-aware construction scheme for decision trees and random forests that transforms the inference phase of these classification models into a set of range queries, which in turn can be efficiently executed by leveraging multidimensional indexing structures. Our experiments show that queries over large data catalogs with hundreds of millions of objects can be processed in a few seconds using a single server, compared to hours needed by classical scanning-based approaches

    Linking bacterial communities associated with the environment and the ecosystem engineer <i>Orchestia gammarellus</i> at contrasting salt marsh elevations

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    The digestive tract of animals harbors microbiota important for the host’s fitness and performance. The interaction between digestive tract bacteria and soil animal hosts is still poorly explored despite the importance of soil fauna for ecosystem processes. In this study, we investigated the interactions between the bacterial communities from the digestive tract of the litter-feeding, semi-terrestrial crustacean Orchestia gammarellus and those obtained from the environment; these organisms thrive in, i.e., soil and plant litter from salt marshes. We hypothesized that elevation is an important driver of soil and litter bacterial communities, which indirectly (via ingested soil and litter bacteria) influences the bacterial communities in the digestive tract of O. gammarellus. Indeed, our results revealed that elevation modulated soil and litter bacterial community composition along with soil organic matter content and the C:N ratio. Soil and plant litter differed in alpha diversity indexes (richness and diversity), and in the case of plant litter, both indexes increased with elevation. In contrast, elevation did not affect the composition of bacterial communities associated with O. gammarellus’ digestive tract, suggesting selection by the host, despite the fact that a large component of the bacterial community was also detected in external sources. Importantly, Ca. Bacilloplasma and Vibrio were highly prevalent and abundant in the host. The taxonomic comparison of Ca. Bacilloplasma amplicon sequence variants across the host at different elevations suggested a phylogenetic divergence due to host habitat (i.e., marine or semi-terrestrial), thus supporting their potential functional role in the animal physiology. Our study sheds light on the influence of the environment on soil animal–bacteria interactions and provides insights into the resilience of the O. gammarellus–associated bacteria to increased flooding frequency

    On the Use of Parametric Wind Models for Wind Wave Modeling under Tropical Cyclones

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    Wave and wind forces from tropical cyclones are one of the main design parameters of coastal and offshore infrastructure in tropical areas. The estimation of ocean waves parameters in the design of structures in tropical areas is difficult due to the complexity of wind fields associated with tropical cyclones. The use of numerical wave models, forced with parametric wind fields, is a common practice within the climatic characterization of extreme events. However, there is currently no consensus on the selection of parametric models for wave prediction due to the lack of a rigorous assessment of different models. In this study, six well-known parametric wind models were tested, compared, and applied in the Gulf of Mexico and the Caribbean Sea. Therefore, the evaluation and comparison of the resulting wind and wave fields are presented, showing that a particular model may best represent a specific event, but, when dealing with a large number of events, the choice of a particular parametric wind model or a combination of them does not guarantee greater accurac

    En tiempos de crisis: hagamos diseño, soñemos un nuevo diseño Innovación, Nuevos Materiales (bio-diseño), Fabricación Digital

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    This new moment of crisis or opportunity of “postpandemic Covid19” and having at our fingertips: biomaterials, digital fabrication and artificial intelligenceEste nuevo momento de crisis o de oportunidad de “pospandemia Covid19” y teniendo al alcance de las manos: biomateriales, fabricación digital y la inteligencia artificial&nbsp;Este novo momento de crise ou oportunidade de “Covid19 póspandêmico” e tendo na ponta dos dedos: biomateriais, fabricação digital e inteligência artificia

    Political science

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    Recent research suggests that prior exposure of several months to elevated irradiance induces enhanced thermal tolerance in scleractinian corals. While this tolerance has been reported at the species level, individual coral colonies may react differently due to individual variability in thermal tolerance. As thermal anomalies are predicted to become common in the upcoming future, intraspecific variation may be key to the survival of coral populations. In order to study light-history based thermal stress responses on individual colonies, we developed a preliminary microcosm experiment where three randomly chosen, aquacultured colonies of the model coral Stylophora pistillata were exposed to two irradiance treatments (200 and 400 μmol photons m−2 s−1) for 31 days, followed by artificially induced heat stress (∼33.4 °C). We found different responses to occur at both the intraspecific and the intracolonial levels, as indicated by either equal, less severe, delayed, and/or even non-necrotic responses of corals previously exposed to the irradiance of 400 compared to 200 μmol photons m−2 s−1. In addition, all individual colonies revealed light-enhanced calcification. Finally, elevated irradiance resulted in a lower chlorophyll a concentration in one colony compared to the control treatment, and the same colony displayed more rapid bleaching compared to the other ones. Taken together, this study highlights the potential importance of intra-individual variability in physiological responses of scleractinian corals and provides recommendations for improving methodological designs for future studies

    Electric control of magnetism at the Fe/BaTiO3 interface

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    Interfacial magnetoelectric coupling is a viable path to achieve electrical writing of magnetic information in spintronic devices. For the prototypical Fe/BaTiO3 system, only tiny changes of the interfacial Fe magnetic moment upon reversal of the BaTiO3 dielectric polarization have been predicted so far. Here, by using X-ray magnetic circular dichroism in combination with high-resolution electron microscopy and first principles calculations, we report on an undisclosed physical mechanism for interfacial magnetoelectric coupling in the Fe/BaTiO3 system. At this interface, an ultrathin oxidized iron layer exists, whose magnetization can be electrically and reversibly switched on and off at room temperature by reversing the BaTiO3 polarization. The suppression/recovery of interfacial ferromagnetism results from the asymmetric effect that ionic displacements in BaTiO3 produces on the exchange coupling constants in the interfacial-oxidized Fe layer. The observed giant magnetoelectric response holds potential for optimizing interfacial magnetoelectric coupling in view of efficient, low-power spintronic devices

    Hurricane Flood Hazard Assessment for the Archipelago of San Andres, Providencia and Santa Catalina, Colombia

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    Despite the low occurrence of tropical cyclones at the archipelago of San Andres, Providencia, and Santa Catalina (Colombia), Hurricane Iota in 2020 made evident the area vulnerability to tropical cyclones as major hazards by obliterating 56.4 % of housing, partially destroying the remaining houses in Providencia. We investigated the hurricane storm surge inundation in the archipelago by forcing hydrodynamic models with synthetic tropical cyclones and hypothetical hurricanes. The storm surge from synthetic events allowed identifying the strongest surges using the probability distribution, enabling the generation of hurricane storm surge flood maps for 100 and 500 year return periods. This analysis suggested that the east of San Andres and Providencia are the more likely areas to be flooded from hurricanes storm surges. The hypothetical events were used to force the hydrodynamic model to create worst-case flood scenario maps, useful for contingency and development planning. Additionally, Hurricane Iota flood levels were calculated using 2D and 1D models. The 2D model included storm surge (SS), SS with astronomical tides (AT), and SS with AT and wave setup (WS), resulting in a total flooded area (percentage related to Providencia's total area) of 67.05 ha (3.25 %), 65.23 ha (3.16 %), and 76.68 ha (3.68%), respectively. While Hurricane Iota occurred during low tide, the WS contributed 14.93 % (11.45 ha) of the total flooded area in Providencia. The 1D approximation showed that during the storm peak in the eastern of the island, the contribution of AT, SS, and wave runup to the maximum sea water level was -3.01%, 46.36%, and 56.55 %, respectively. This finding provides evidence of the water level underestimation in insular environments when modeling SS without wave contributions. The maximum SS derived from Iota was 1.25 m at the east of Providencia, which according to this study has an associated return period of 3,234 years. The methodology proposed in this study can be applied to other coastal zones and may include the effect of climate change on hurricane storm surges and sea-level rise. Results from this study are useful for emergency managers, government, coastal communities, and policymakers as civil protection measures

    Treatment of Older Patients With Mantle Cell Lymphoma (MCL):Long-Term Follow-Up of the Randomized European MCL Elderly Trial

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    PURPOSE: In an update of the randomized, open-label, phase III European Mantle Cell Lymphoma (MCL) Elderly trial (ClinicalTrials.gov identifier: NCT00209209), published in 2012, we aimed to confirm results on long-term outcome focusing on efficacy and safety of long-term use of rituximab maintenance. PATIENTS AND METHODS: Five hundred sixty patients with newly diagnosed MCL underwent a first random assignment between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and rituximab, fludarabine, and cyclophosphamide (R-FC) induction, followed by a second random assignment in 316 responders between rituximab and interferon alfa maintenance, to be continued until progression. We compared progression-free survival from the second randomization and overall survival (OS) from the first or second randomizations. RESULTS: After a median follow-up time of 7.6 years, the previously described difference in OS between the induction arms persisted (median, 6.4 years after R-CHOP [n = 280] v 3.9 years after R-FC [n = 280]; P = .0054). Patients responding to R-CHOP had median progression-free survival and OS times of 5.4 and 9.8 years, respectively, when randomly assigned to rituximab (n = 87), compared with 1.9 years (P < .001) and 7.1 years (P = .0026), respectively, when randomly assigned to interferon alfa (n = 97). In 58% and 32% of patients treated with R-CHOP, rituximab maintenance was still ongoing 2 and 5 years from start of maintenance, respectively. After R-FC, rituximab maintenance was associated with an unexpectedly high cumulative incidence of death in remission (22% at 5 years). Toxicity of rituximab maintenance was low after R-CHOP (grade 3-4 leukopenia or infection < 5%) but more prominent in patients on rituximab maintenance after R-FC, in whom grade 3-4 leukopenia (up to 40%) and infections were frequent (up to 15%). CONCLUSION: The excellent results of R-CHOP followed by rituximab maintenance until progression for older patients with MCL persisted in a mature follow-up. Prolongation of rituximab maintenance beyond 2 years is effective and safe
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