4,313 research outputs found

    Mucuna tapantiana (Fabaceae: Faboideae: Phaseoleae), a new species from Costa Rica

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    A new species of Mucuna (Fabaceae: Faboideae: Phaseoleae), endemic to Costa Rica, is described and illustrated. Mucuna tapantiana is distinguished by its small, essentially glabrous leaflets, conspicuous filiform peduncle and pedicels, inflorescences with few green or yellowish-green flowers; fruits with softly villous, yellowish or brownish pubescence on the outer surface (when fresh), but without urticating trichomes, turning dark brown or blackish when dry, 1 - 2-seeded; seeds oblong and laterally compressed691COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESMissouri Botanical Garden; Universidad Estadual at Campina

    Vortex dynamics in a compact Kardar-Parisi-Zhang system

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    We study the dynamics of vortices in a two-dimensional, non-equilibrium system, described by the compact Kardar-Parisi-Zhang equation, after a sudden quench across the critical region. Our exact numerical solution of the phase-ordering kinetics shows that the unique interplay between non-equilibrium and the variable degree of spatial anisotropy leads to different critical regimes. We provide an analytical expression for the vortex evolution, based on scaling arguments, which is in agreement with the numerical results, and confirms the form of the interaction potential between vortices in this system.Comment: 5 pages, 3 figures and Supplementary Materia

    Positive adjacency effects mediated by seed disperser birds in pine plantations

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    This study examines the consequences of adjacent elements for a given patch, through their effects on zoochorous dispersion by frugivorous birds. The case study consists of pine plantations (the focal patch) adjacent to other patches of native vegetation (mixed patches of native forest and shrublands), and/or pine plantations. Our hypothesis is that input of native woody species propagules generated by frugivorous birds within plantations strongly depends on the nature of the surrounding vegetation. To test this hypothesis, we studied frugivorous-bird abundance, seed dispersion, and seedling establishment in nine pine plantation plots in contact with patches of native vegetation. To quantify adjacency arrangement effects, we used the percentage of common border between a patch and each of its adjacent elements. Frugivorous bird occurrence in pine plantations is influenced by the adjacent vegetation: the greater the contact with native vegetation patches, the more abundant were the frugivorous birds within pine plantations. Furthermore, frugivorous birds introduce into plantations the seeds of a large sample of native fleshy-fruited species. The results confirm the hypothesis that zoochorous seed rain is strongly determined by the kind of vegetation surrounding a given plantation. This finding underlines the importance of the composition of the mosaic surrounding plantations and the availability of mobile link species as key landscape features conditioning passive restoration processes

    Management of first-trimester miscarriage: a systematic review and network meta-analysis

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    Background First-trimester miscarriage affects up to a quarter of women worldwide. With many competing treatment options available, there is a need for a comprehensive evidence synthesis. Objectives and rationale We conducted a systematic review and network meta-analysis to assess the effectiveness and safety of treatment options for first-trimester miscarriage: expectant management (EXP), sharp dilation and curettage (D+C), electric vacuum aspiration (EVAC), manual vacuum aspiration (MVA), misoprostol alone (MISO), mifepristone+misoprostol (MIFE+MISO) and misoprostol plus electric vacuum aspiration (MISO+EVAC). Search methods We searched MEDLINE, Embase, CINAHL, AMED and Cochrane Library from inception till June 2018. We included randomized trials of women with first-trimester miscarriage (<14 weeks gestation) and conducted a network meta-analysis generating both direct and mixed evidence on the effectiveness and side effects of available treatment options. The primary outcome was complete evacuation of products of conception. We assessed the risk of bias and the global network inconsistency. We compared the surface under the cumulative ranking curve (SUCRA) for each treatment. Outcomes A total of 46 trials (9250 women) were included. The quality of included studies was overall moderate with some studies demonstrating a high risk of bias. We detected unexplained inconsistency in evidence loops involving MIFE+MISO and adjusted for it. EXP had lower effectiveness compared to other treatment options. The effectiveness of medical treatments was similar compared to surgery. Mixed evidence of low confidence suggests increased effectiveness for MIFE+MISO compared to MISO alone (RR 1.49, 95% CI: 1.09–2.03). Side effects were similar among all options. Fewer women needed analgesia following EVAC compared to MISO (RR for MISO 0.43, 95% CI: 0.27–0.68) and in the EXP group compared to EVAC (RR 2.07, 95% CI: 1.25–3.41). MVA had higher ranking (low likelihood) for post-treatment infection and serious complications (SUCRA 87.6 and 79.2%, respectively) with the highest likelihood for post-treatment satisfaction (SUCRA 98%). Wider implications Medical treatments for first-trimester miscarriage have similar effectiveness and side effects compared to surgery. The addition of MIFE could increase the effectiveness of MISO and reduce side effects, although evidence is limited due to inconsistency. EXP has lower effectiveness compared to other treatment options

    Plasma oxylipins and unesterified precursor fatty acids are altered by DHA supplementation in pregnancy: Can they help predict risk of preterm birth?

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    Oxidized lipids derived from omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids, collectively known as oxylipins, are bioactive signaling molecules that play diverse roles in human health and disease. Supplementation with n-3 docosahexaenoic acid (DHA) during pregnancy has been reported to decrease the risk of preterm birth in singleton pregnancies, which may be due to effects of DHA supplementation on oxylipins or their precursor n-6 and n-3 fatty acids. There is only limited understanding of the levels and trajectory of changes in plasma oxylipins during pregnancy, effects of DHA supplementation on oxylipins and unesterified fatty acids, and whether and how oxylipins and their unesterified precursor fatty acids influence preterm birth. In the present study we used liquid chromatography-tandem mass spectrometry to profile oxylipins and their precursor fatty acids in the unesterified pool using plasma samples collected from a subset of pregnant Australian women who participated in the ORIP (Omega-3 fats to Reduce the Incidence of Prematurity) study. ORIP is a large randomized controlled trial testing whether daily supplementation with n-3 DHA can reduce the incidence of early preterm birth compared to control. Plasma was collected at study entry (≈pregnancy week 14) and again at ≈week 24, in a subgroup of 48 ORIP participants-12 cases with spontaneous preterm (&lt;37 weeks) birth and 36 matched controls with spontaneous term (≥40 weeks) birth. In the combined preterm and term pregnancies, we observed that in the control group without DHA supplementation unesterified AA and AA-derived oxylipins 12-HETE, 15-HETE and TXB2 declined between weeks 14-24 of pregnancy. Compared to control, DHA supplementation increased unesterified DHA, EPA, and AA, DHA-derived 4-HDHA, 10-HDHA and 19,20-EpDPA, and AA-derived 12-HETE at 24 weeks. In exploratory analysis independent of DHA supplementation, participants with concentrations above the median for 5-lipoxygenase derivatives of AA (5-HETE, Odds Ratio (OR) 8.2; p = 0.014) or DHA (4-HDHA, OR 8.0; p = 0.015) at 14 weeks, or unesterified AA (OR 5.1; p = 0.038) at 24 weeks had higher risk of spontaneous preterm birth. The hypothesis that 5-lipoxygenase-derived oxylipins and unesterified AA could serve as mechanism-based biomarkers predicting spontaneous preterm birth should be evaluated in larger, adequately powered studies

    Kibble-Zurek mechanism in driven-dissipative systems crossing a non-equilibrium phase transition

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    The Kibble-Zurek mechanism constitutes one of the most fascinating and universal phenomena in the physics of critical systems. It describes the formation of domains and the spontaneous nucleation of topological defects when a system is driven across a phase transition exhibiting spontaneous symmetry breaking. While a characteristic dependence of the defect density on the speed at which the transition is crossed was observed in a vast range of equilibrium condensed matter systems, its extension to intrinsically driven-dissipative systems is a matter of ongoing research. In this work we numerically confirm the Kibble-Zurek mechanism in a paradigmatic family of driven-dissipative quantum systems, namely exciton-polaritons in microcavities. Our findings show how the concepts of universality and critical dynamics extend to driven-dissipative systems that do not conserve energy or particle number nor satisfy a detailed balance condition
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