14,448 research outputs found

    Geomorfologia e a biodiversidade no Pantanal

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    The present study deals with the inter-relations in the relief which forms the Bacia do Alto Rio Paraguay (BAP) in mid-west Brazil. The overall aim is to discuss the relationship between relief forms and the biodiversity of the Pantanal. The BAP is a natural environmental system with contrasts in two of the compartments on which it is formed: the plateau, the most elevated compartment, highly transformed by human activities, and the plain which forms the Pantanal, which is more preserved and less transformed in relation to productive activities. The analysis was performed based on publications with a geomorphologic focus, examining the different relief units of the BAP and the dynamics of the revealing processes of landscape change which the Pantanal has undergone since the end of the Pleistocene.O presente estudo tem como objetivo abordar a inter-relação entre os compartimentos do relevo brasileiro que compõem a Bacia do Alto Paraguai - BAP, para discutir as formas de relevo e a biodiversidade do Pantanal. A abordagem fundamenta-se na compreensão das diferentes formas do terreno, associando ao fato que a BAP é um sistema ambiental natural que tem contrastes nos dois compartimentos que a compõem: o planalto, o compartimento mais elevado, fortemente transformado por atividades humanas; e a planície, que constitui o Pantanal mato-grossense, mais conservada e pouco transformada, quanto ao uso com atividades produtivas. A análise foi realizada a partir de publicações com enfoques geomorfológicos, abordando as diferentes unidades do relevo da BAP e o entendimento da dinâmica dos processos reveladores de que o Pantanal passa desde o fim do Pleistoceno, com processos de mudanças da paisagem.MEC - CAPE

    Biochemical analysis of TssK, a core component of the bacterial Type VI secretion system, reveals distinct oligomeric states of TssK and identifies a TssK–TssFG subcomplex

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    Gram-negative bacteria use the Type VI secretion system (T6SS) to inject toxic proteins into rival bacteria or eukaryotic cells. However, the mechanism of the T6SS is incompletely understood. In the present study, we investigated a conserved component of the T6SS, TssK, using the antibacterial T6SS of Serratia marcescens as a model system. TssK was confirmed to be essential for effector secretion by the T6SS. The native protein, although not an integral membrane protein, appeared to localize to the inner membrane, consistent with its presence within a membrane-anchored assembly. Recombinant TssK purified from S. marcescens was found to exist in several stable oligomeric forms, namely trimer, hexamer and higher-order species. Native-level purification of TssK identified TssF and TssG as interacting proteins. TssF and TssG, conserved T6SS components of unknown function, were required for T6SS activity, but not for correct localization of TssK. A complex containing TssK, TssF and TssG was subsequently purified in vitro, confirming that these three proteins form a new subcomplex within the T6SS. Our findings provide new insight into the T6SS assembly, allowing us to propose a model whereby TssK recruits TssFG into the membrane-associated T6SS complex and different oligomeric states of TssK may contribute to the dynamic mechanism of the system

    Dynamics of Bloch vectors and the channel capacity of a non identical charged qubit pair

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    We have considered a system of two superconducting charge qubits capacitively coupled to a microwave resonator. The dynamics of the Bloch vectors are investigated for different regimes. By means of the Bloch vectors and cross dyadic we quantify the degree of entanglement contained in the generated entangled state. We consider different values of the system parameters to discuss the dynamics of the channel capacity between the qubits. We show that there is an important role played by initial state settings, coupling constant and the mean photon number on generating entangled state with high degree of entanglement and high capacity

    Susceptibility of Candida glabrata biofilms to echinocandins: alterations in the matrix composition

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    Candidiases are the most recurrent fungal infections, especially among immunosuppressed patients. Although Candida albicans is still the most widespread isolated species, non-Candida albicans Candida species have been increasing. The goal of this work was to determine the susceptibility of C. glabrata biofilms to echinocandins and to evaluate their effect on the biofilm matrix composition, comparing the results with other Candida species. Drug susceptibilities were assessed through the determination of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum biofilm eradication concentration (MBEC) of caspofungin (Csf) and micafugin (Mcf). The -1,3 glucans content of the matrices was assessed after contact with the drugs. The data suggest that, generally, after contact with echinocandins, the concentration of -1,3 glucans increased. These adjustments in the matrix composition of C. glabrata biofilms and the chemical differences between Csf and Mcf, seem responsible and may determine the effectivity of the drug responses.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 [POCI-01–0145-FEDER-006684] and BioTecNorte operation [NORTE-01–0145-FEDER-000004] funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, Célia F. Rodrigues’ [SFRH/BD/93078/2013] PhD grant and M. Elisa Rodrigues [SFRH/BPD/95401/2013] post-doctoral grant.info:eu-repo/semantics/publishedVersio

    Train-the-trainers in hand hygiene : a standardized approach to guide education in infection prevention and control

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    Background Harmonization in hand hygiene training for infection prevention and control (IPC) professionals is lacking. We describe a standardized approach to training, using a “Train-the-Trainers” (TTT) concept for IPC professionals and assess its impact on hand hygiene knowledge in six countries.Methods We developed a three-day simulation-based TTT course based on the World Health Organization (WHO) Multimodal Hand Hygiene Improvement Strategy. To evaluate its impact, we have performed a pre-and post-course knowledge questionnaire. The Wilcoxon signed-rank test was used to compare the results before and after training.Results Between June 2016 and January 2018 we conducted seven TTT courses in six countries: Iran, Malaysia, Mexico, South Africa, Spain and Thailand. A total of 305 IPC professionals completed the programme. Participants included nurses (n = 196; 64.2%), physicians (n = 53; 17.3%) and other health professionals (n = 56; 18.3%). In total, participants from more than 20 countries were trained. A significant (p < 0.05) improvement in knowledge between the pre- and post-TTT training phases was observed in all countries. Puebla (Mexico) had the highest improvement (22.3%; p < 0.001), followed by Malaysia (21.2%; p < 0.001), Jalisco (Mexico; 20.2%; p < 0.001), Thailand (18.8%; p < 0.001), South Africa (18.3%; p < 0.001), Iran (17.5%; p < 0.001) and Spain (9.7%; p = 0.047). Spain had the highest overall test scores, while Thailand had the lowest pre- and post-scores. Positive aspects reported included: unique learning environment, sharing experiences, hands-on practices on a secure environment and networking among IPC professionals. Sustainability was assessed through follow-up evaluations conducted in three original TTT course sites in Mexico (Jalisco and Puebla) and in Spain: improvement was sustained in the last follow-up phase when assessed 5 months, 1 year and 2 years after the first TTT course, respectively.Conclusions The TTT in hand hygiene model proved to be effective in enhancing participant’s knowledge, sharing experiences and networking. IPC professionals can use this reference training method worldwide to further disseminate knowledge to other health care workers.peer-reviewe

    Migraine aura: retracting particle-like waves in weakly susceptible cortex

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    Cortical spreading depression (SD) has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD and aura symptoms on the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value [sigma]=1 at the instability point. We predict that human cortex is only weakly susceptible to SD ([sigma]&#x3c;1), and support this prediction by directly matching visual aura symptoms with anatomical landmarks using fMRI retinotopic mapping. We discuss the increased dynamical repertoire of cortical tissue close to [sigma]=1, in particular, the resulting implications on migraine pharmacology that is hitherto tested in the regime ([sigma]&#x3e;&#x3e;1), and potentially silent aura occurring below a second bifurcation point at [sigma]=0 on the susceptible scale

    Liver haemangioma: common and uncommon findings and how to improve the differential diagnosis

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    Haemangiomas are common focal liver lesions, generally detected in the work-up of asymptomatic patients. From the pathological point of view, they can be classified as small (capillary) or large, with cavernous vascular spaces that may show thrombosis, calcifications and hyalinisation. The polymorphic imaging appearance of haemangiomas depends on their histological features and flow pattern. The widespread use of cross-sectional imaging has allowed an increased detection rate and a better characterisation of this benign tumour. Recent developments of ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) providing high spatial and temporal resolution, together with the use of new contrast agents and/or pulse sequences has broadened the spectrum of imaging findings, contributing to diagnostic refinement in difficult cases. The scope of the present article is to provide an overview of the range of appearances of haemangiomas, explored with recent cross-sectional imaging modalities, emphasising its atypical findings as explored by temporally resolved contrast-enhanced imaging

    Laboratory Tests of Low Density Astrophysical Equations of State

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    Clustering in low density nuclear matter has been investigated using the NIMROD multi-detector at Texas A&M University. Thermal coalescence modes were employed to extract densities, ρ\rho, and temperatures, TT, for evolving systems formed in collisions of 47 AA MeV 40^{40}Ar + 112^{112}Sn,124^{124}Sn and 64^{64}Zn + 112^{112}Sn, 124^{124}Sn. The yields of dd, tt, 3^{3}He, and 4^{4}He have been determined at ρ\rho = 0.002 to 0.032 nucleons/fm3^{3} and TT= 5 to 10 MeV. The experimentally derived equilibrium constants for α\alpha particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.Comment: 5 pages, 3 figure

    Isobaric Yield Ratios and The Symmetry Energy In Fermi Energy Heavy Ion Reactions

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    The relative isobaric yields of fragments produced in a series of heavy ion induced multifragmentation reactions have been analyzed in the framework of a Modified Fisher Model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, aa/Ta_a/T, as a function of fragment mass A. The extracted values increase from 5 to ~16 as A increases from 9 to 37. These values have been compared to the results of calculations using the Antisymmetrized Molecular Dynamics (AMD) model together with the statistical decay code Gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the ratios determined from fitting the primary fragment distributions from the AMD model calculation are ~ 4 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.Comment: 10 pages, 12 figure

    Incidence and diversity of the fungal genera Aspergillus and Penicillium in Portuguese almonds and chestnuts

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    Almonds (Prunus dulcis (Miller) D.A. Webb) and European (sweet) chestnuts (Castanea sativa Miller) are of great economic and social impact in Mediterranean countries, and in some areas they constitute the main income of rural populations. Despite all efforts to control fungal contamination, toxigenic fungi are ubiquitous in nature and occur regularly in worldwide food supplies, and these nuts are no exception. This work aimed to provide knowledge on the general mycobiota of Portuguese almonds and chestnuts, and its evolution from field to the end of storage. For this matter, 45 field chestnut samples and 36 almond samples (30 field samples and six storage samples) were collected in Trás-os-Montes, Portugal. All fungi belonging to genus Aspergillus were isolated and identified to the section level. Fungi representative of other genera were identified to the genus level. In the field, chestnuts were mainly contaminated with the genera Fusarium, Cladosporium, Alternaria and Penicillium, and the genus Aspergillus was only rarely found, whereas almonds were more contaminated with Aspergillus. In almonds, Aspergillus incidence increased significantly from field to the end of storage, but diversity decreased, with potentially toxigenic isolates belonging to sections Flavi and Nigri becoming more significant and widespread throughout storage. These fungi were determined to be moderately associated, which can be indicative of mycotoxin co-contamination problems if adequate storage conditions are not secured.P. Rodrigues was supported by grants SFRH/BD/28332/2006 from Fundacao para a Ciencia e a Tecnologia (FCT), and SFRH/PROTEC/49555/2009 from FCT and Polytechnic Institute of Braganca, Portugal
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