1,511 research outputs found

    The magnitude and extent of edge effects on vascular epiphytes across the Brazilian Atlantic Forest

    Get PDF
    Edge effects are ubiquitous landscape processes influencing over 70% of forest cover worldwide. However, little is known about how edge effects influence the vertical stratification of communities in forest fragments. We combined a spatially implicit and a spatially explicit approach to quantify the magnitude and extent of edge effects on canopy and understorey epiphytic plants in the Brazilian Atlantic Forest. Within the human-modified landscape, species richness, species abundance and community composition remained practically unchanged along the interior-edge gradient, pointing to severe biotic homogenisation at all strata. This is because the extent of edge effects reached at least 500 m, potentially leaving just 0.24% of the studied landscape unaffected by edges. We extrapolated our findings to the entire Atlantic Forest and found that just 19.4% of the total existing area is likely unaffected by edge effects and provide suitable habitat conditions for forest-dependent epiphytes. Our results suggest that the resources provided by the current forest cover might be insufficient to support the future of epiphyte communities. Preserving large continuous ‘intact’ forests is probably the only effective conservation strategy for vascular epiphytes

    Neutral‐based processes overrule niche‐based processes in shaping tropical montane orchid communities across spatial scales

    Get PDF
    Tropical montane forests (TMF) are characterised by high endemism, species richness and turnover across elevations. A key question is how niche-based processes, via adaptation of species to local environmental conditions, and neutral-based processes from dispersal limitation shape community composition at different spatial scales across human-modified landscapes. We expect that (1) communities are highly distinct even within the same habitat type and (2) niche-based processes play the main role in compositional turnover. To address these expectations, we investigated the compositional turnover of orchids, one of the most prominent floristic elements of TMFs. We sampled orchids in 332 plots spanning over 270 km in the eastern Colombian Andes. Plots ranged between elevations of 1160–3750 m. We used two different spatial extents (whole gradient and two elevational bands), two grains of analysis for the first expectation (regional and local) and two spatial grains for the second expectation (broad and fine scales based on Moran's Eigenvector Maps [MEMs]). We found 331 orchid species in 171 (51%) plots. We found a strong pattern of high compositional turnover across scales (>72% of total beta diversity is given by species turnover), with 87.5% of the total species pool occurring in fewer than five plots, supporting our first expectation. Contrary to our second expectation, we found that community composition is mainly driven by geographical distance, while the relative influence of elevation, environmental variables and their combined fractions were negligible across habitats and spatial scales, rejecting niche-based processes. Synthesis. High compositional turnover, even across habitats with the highest degree of human intervention, suggests that both forest-dwelling and open-habitat species do not easily disperse across habitats. Species dispersal is the major force of orchid community turnover and might be strongly dependent upon macroevolutionary processes and species life-history traits over multiple scales. Dispersal limitation also draws attention to the importance of preserving habitat connectivity to halt biodiversity losses

    Serum levels and removal by haemodialysis and haemodiafiltration of tryptophan-derived uremic toxins in ESKD patients

    Get PDF
    Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD. Blood and spent dialysate samples obtained during dialysis were analysed with high-performance liquid chromatography to assess uremic solutes, their reduction ratio (RR) and total removed solute (TRS). Mean free serum tryptophan and IS concentrations increased, and concentration of IAA decreased over pre-dialysis levels (67%, 49%, -0.8%, respectively) during the first hour of dialysis. While mean serum total urea, IS and IAA concentrations decreased during dialysis (-72%, -39%, -43%, respectively), serum tryptophan levels increased, resulting in negative RR (-8%) towards the end of the dialysis session (p < 0.001), despite remarkable Trp losses in dialysate. RR and TRS values based on serum (total, free) and dialysate solute concentrations were lower for conventional low-flux dialysis (p < 0.001). High-efficiency haemodiafiltration resulted in 80% higher Trp losses than conventional low-flux dialysis, despite similar neutral Trp RR values. In conclusion, serum Trp concentrations and RR behave differently from uremic solutes IS, IAA and urea and Trp RR did not reflect dialysis Trp losses. Conventional low-flux dialysis may not adequately clear Trp-related uremic toxins while high efficiency haemodiafiltration increased Trp losses

    Maternal Serum Meteorin Levels and the Risk of Preeclampsia

    Get PDF
    BACKGROUND: Meteorin (METRN) is a recently described neutrophic factor with angiogenic properties. This is a nested case-control study in a longitudinal cohort study that describes the serum profile of METRN during different periods of gestation in healthy and preeclamptic pregnant women. Moreover, we explore the possible application of METRN as a biomarker. METHODS AND FINDINGS: Serum METRN was measured by ELISA in a longitudinal prospective cohort study in 37 healthy pregnant women, 16 mild preeclamptic women, and 20 healthy non-pregnant women during the menstrual cycle with the aim of assessing serum METRN levels and its correlations with other metabolic parameters. Immunostaining for METRN protein was performed in placenta. A multivariate logistic regression model was proposed and a classifier model was formulated for predicting preeclampsia in early and middle pregnancy. The performance in classification was evaluated using measures such as sensitivity, specificity, and the receiver operating characteristic (ROC) curve. In healthy pregnant women, serum METRN levels were significantly elevated in early pregnancy compared to middle and late pregnancy. METRN levels are significantly lower only in early pregnancy in preeclamptic women when compared to healthy pregnant women. Decision trees that did not include METRN levels in the first trimester had a reduced sensitivity of 56% in the detection of preeclamptic women, compared to a sensitivity of 69% when METRN was included. CONCLUSIONS: The joint measurements of circulating METRN levels in the first trimester and systolic blood pressure and weight in the second trimester significantly increase the probabilities of predicting preeclampsia

    HEMIC Project: Design of a Clinical Information Modelling Tool Based on ISO13972 Technical Specification

    Get PDF
    The Andalusian Health Service is the public healthcare provider for 8.302.923 inhabitants in the South Spain. This organization coordinates primary and specialized care with an IT infrastructure composed by multiple Electronic Health Record Systems. According to the large volume of healthcare professionals involved, there is a need for providing a consistent management of information through multiple locations and systems. The HEMIC project aims to address this need developing and validating a methodology based on a software tool for standardizing information contained within EHR systems. The developed tool has been designed for supporting the participation of healthcare professionals the establishment of mechanisms for information governance. This research presents the requirements and designs for of a software tool focused on the adoption of recognized best practice in clinical information modeling. The designed tool has a Service Oriented Architecture that will be able to integrate terminology servers and repositories of clinical information models as part of the modeling process. Moreover, the defined tool organizes clinicians, IT developers and terminology experts involved in the modeling process in three levels to promote their coordination in the definition, specialization and validation of clinical information models. In order to ensure the quality of the developed clinical information models, the defined tool is based on the requirements defined in the ISO13972 Technical Specification

    Spatial characteristics and temporal evolution of chemical and biological freshwater status as baseline assessment on the tropical island San CristĂłbal (Galapagos, Ecuador)

    Get PDF
    The fragility of geographically isolated islands stresses the necessity of evaluating the current situation, identifying temporal trends and suggesting appropriate conservation measures. To support this, we assessed the freshwater quality of three stream basins on San Cristóbal (Galapagos) for two consecutive years. Abiotic conditions generally complied with existing guidelines, except for the pH in the Cerro Gato basin (0.12 mg P L−1). Macroinvertebrate communities were characterized by low family richness (3–11) and were dominated by Atyidae or Chironomidae, thereby causing low diversity (0.33–1.65). Spatial analysis via principal component analysis (PCA) illustrated that abiotic differences between stream basins were mostly related to turbidity, pH, dissolved oxygen (DO), and conductivity. Biotic differences were less clear due to masking by anthropogenic disturbances and dispersal limitations, yet indicated a negative effect of reduced pH and DO on Atyidae presence. In 2017, significantly narrower ranges were found for turbidity, temperature, pH, and diversity (p < 0.01), suggesting a decrease in habitat variability and a need for conservation measures, including mitigating measures related to dam construction for water extraction. As such, further follow-up is highly recommended for the sustainable development and environmental protection of this unique archipelago

    Virulence and Antibiotic Resistance Profiles of Cronobacter sakazakii and Enterobacter spp. Involved in the Diarrheic Hemorrhagic Outbreak in Mexico

    Get PDF
    Cronobacter spp. are bacterial pathogens that cause neonatal meningitis, septicemia, and necrotizing enterocolitis in infants with a lethality rate of 40–80%. Powdered infant formulas (PIF) have been implicated as the main vehicles of transmission. This pathogen can also cause infection through contaminated expressed breast milk, and it has been recovered from neonatal feeding tubes of neonates not fed reconstituted PIF and milk kitchen areas. This study analyzed antibiotic resistance profiles and the tissue virulence tests of Cronobacter sakazakii and Enterobacter spp. recovered from PIF, infant fecal matter‘s, and milk kitchen environment involved in a diarrheic hemorrhagic outbreak in 2011 in Mexico. The strains isolated from the outbreak had similar antibiotic resistance profiles and pathogenicity irrespective of isolation site, however, C. sakazakii strains isolated from PIF showed significantly higher invasive profiles than Enterobacter spp. (p = 0.001) and 83% were resistant to more than one antibiotic. The findings of this study can be used to complement existing information to better control Cronobacter and Enterobacter spp. contamination in PIF production, prevent its transmission, and improve infant food safety

    GEMINI 3D spectroscopy of BAL+IR+Fe II QSOs: II. IRAS 04505-2958 an explosive QSO with hypershell and a new scenario for galaxy formation and galaxy end

    Full text link
    From a study of BAL + IR + Fe II QSOs (using deep Gemini GMOS-IFU spectroscopy) new results are presented: for IRAS 04505-2958. Specifically, we have studied in detail the out flow (OF) process and their associated structures, mainly at two large galactic scales: (i) two blobs/shells (S1, S2) at radius r = 1.1 and 2.2 kpc; and (ii) an external hypergiant shell (S3) at r = 11 kpc. In addition, the presence of two very extended hypergiant shells (S4, S5) at r = 80 kpc is discussed. From this GMOS study the following main results were obtained: (i) For the external hypergiant shell S3 the kinematics GMOS maps of the ionized gas show very similar features to those observed for the prototype of exploding external supergiant shell: in NGC 5514. (ii) The main knots K1, K2 and K3 -of this hypergiant shell S3- show a stellar population and emission line ratios associated with the presence of a starburst + OF/shocks. (iii) The internal shells S1 and S2 show structures, OF components and properties very similar to those detected in the nuclear shells of Mrk 231. (iv) The shells S1+S2 and S3 are aligned at PA = 131: i.e. suggesting that the OF process is in the blow-out phase with bipolar structure. In addition, the shells S4 and S5 (at 80-100 kpc scale) are aligned at PA = 40, i.e.: a bipolar OF perpendicular to the internal OF. Finally, the generation of UHE cosmic rays and neutrino/ dark-matter -associated with HyNe in BAL + IR + Fe II QSOs- is discussed.Comment: Submitted MNRAS, 81 pages, 25 Figure
    • 

    corecore