2,119 research outputs found

    PRE-COPULATORY SEXUAL CANNIBALISM IN FISHING SPIDERS: THE ECOLOGY OF AN EXTREME SEXUAL CONFLICT

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    Pre-copulatory sexual cannibalism (pre-SC), or predation of a potential mate before sperm transfer, provides an ideal model system for behavioral ecology\u27s current focus on inter-sexual conflict. Studying the North American fishing spider (Dolomedes triton), I tested three female-benefit hypotheses for pre-SC: indirect benefits, direct benefits, and aggressive spillover. First, pre-SC may reflect a mating bias providing females with \u27good-genes\u27 benefits. By manipulating each female\u27s options with regard to the most cited phenotypic advantage in male spiders, body size, I show that while females exhibit no bias in their attack tendency on males of different body sizes, large males mate significantly more often than small males. Second, pre-SC may be explained by direct benefits if females use it as an adaptive foraging/mating trade-off. My work provides mixed support for this idea: (i) females vary attacks according to the availability of mates, (ii) females do not vary attacks according to the availability of food, and (iii) females derive discrete fecundity benefits from consuming a male. Finally, I tested the aggressive-spillover hypothesis, which posits that pre-SC is a by-product of selection for high levels of aggression towards prey in traditional foraging contexts. Path analysis indicated intra-individual, positive correlations between aggression in foraging contexts and the mating context, thus supporting the hypothesis. I conclude by stressing that pre-SC in a given species may rarely be explained by one hypothesis, and that studies accounting for multiple benefits that fluctuate as behavioral-ecological contexts shift should give a more realistic glimpse of behavioral ecology and evolution

    Size determination of the Centaur Chariklo from millimeter-wavelength bolometer observations

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    Using the Max-Planck Millimeter Bolometer Array (MAMBO) at the IRAM 30m telescope we detected emission at 250 GHz from the Centaur Chariklo (1997 CU26). The observed continuum flux density implies a photometric diameter of 273 km. The resulting geometric albedo is 0.055, somewhat higher than expected from a comparison with most of the other few Centaurs and cometary nuclei for which such data are available.Comment: 4 pages, 1 Postscript figure, to appear in Astronomy & Astrophysic

    Incomplete reversibility of estimated glomerular filtration rate decline following tenofovir disoproxil fumarate exposure.

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    BACKGROUND: Tenofovir disoproxil fumarate (TDF) has been linked to renal impairment, but the extent to which this impairment is reversible is unclear. We aimed to investigate the reversibility of renal decline during TDF therapy. METHODS: Cox proportional hazards models assessed factors associated with discontinuing TDF in those with an exposure duration of >6 months. In those who discontinued TDF therapy, linear piecewise regression models estimated glomerular filtration rate (eGFR) slopes before initiation of, during, and after discontinuation of TDF therapy. Factors associated with not achieving eGFR recovery 6 months after discontinuing TDF were assessed using multivariable logistic regression. RESULTS: We observed declines in the eGFR during TDF exposure (mean slopes, -15.7 mL/minute/1.73 m(2)/year [95% confidence interval {CI}, -20.5 to -10.9] during the first 3 months and -3.1 mL/minute/1.73 m(2)/year [95% CI, -4.6 to -1.7] thereafter) and evidence of eGFR increases following discontinuation of TDF therapy (mean slopes, 12.5 mL/minute/1.73 m(2)/year [95% CI, 8.9-16.1] during the first 3 months and 0.8 mL/minute/1.73 m(2)/year [95% CI,.1-1.5] thereafter). Following TDF discontinuation, 38.6% of patients with a decline in the eGFR did not experience recovery. A higher eGFR at baseline, a lower eGFR after discontinuation of TDF therapy, and more-prolonged exposure to TDF were associated with an increased risk of incomplete recovery 6 months after discontinuation of TDF therapy. CONCLUSIONS: This study shows that a decline in the eGFR during TDF therapy was not fully reversible in one third of patients and suggests that prolonged TDF exposure at a low eGFR should be avoided

    Central nervous system relapse of diffuse large B-cell lymphoma in the rituximab era: results of the UK NCRI R-CHOP-14 versus 21 trial

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    Background: Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is associated with a dismal prognosis. Here, we report an analysis of CNS relapse for patients treated within the UK NCRI phase III R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) 14 versus 21 randomised trial. Patients and methods: The R-CHOP 14 versus 21 trial compared R-CHOP administered two- versus three weekly in previously untreated patients aged ≥18 years with bulky stage I-IV DLBCL (n = 1080). Details of CNS prophylaxis were retrospectively collected from participating sites. The incidence and risk factors for CNS relapse including application of the CNS-IPI were evaluated. Results: 177/984 patients (18.0%) received prophylaxis (intrathecal (IT) methotrexate (MTX) n = 163, intravenous (IV) MTX n = 2, prophylaxis type unknown n = 11 and IT MTX and cytarabine n = 1). At a median follow-up of 6.5 years, 21 cases of CNS relapse (isolated n = 11, with systemic relapse n = 10) were observed, with a cumulative incidence of 1.9%. For patients selected to receive prophylaxis, the incidence was 2.8%. Relapses predominantly involved the brain parenchyma (81.0%) and isolated leptomeningeal involvement was rare (14.3%). Univariable analysis demonstrated the following risk factors for CNS relapse: performance status 2, elevated lactate dehydrogenase, IPI, >1 extranodal site of disease and presence of a 'high-risk' extranodal site. Due to the low number of events no factor remained significant in multivariate analysis. Application of the CNS-IPI revealed a high-risk group (4-6 risk factors) with a 2- and 5-year incidence of CNS relapse of 5.2% and 6.8%, respectively. Conclusion: Despite very limited use of IV MTX as prophylaxis, the incidence of CNS relapse following R-CHOP was very low (1.9%) confirming the reduced incidence in the rituximab era. The CNS-IPI identified patients at highest risk for CNS recurrence. ClinicalTrials.gov: ISCRTN number 16017947 (R-CHOP14v21); EudraCT number 2004-002197-34

    Phase Shift from a Coral to a Corallimorph-Dominated Reef Associated with a Shipwreck on Palmyra Atoll

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    Coral reefs can undergo relatively rapid changes in the dominant biota, a phenomenon referred to as phase shift. Various reasons have been proposed to explain this phenomenon including increased human disturbance, pollution, or changes in coral reef biota that serve a major ecological function such as depletion of grazers. However, pinpointing the actual factors potentially responsible can be problematic. Here we show a phase shift from coral to the corallimorpharian Rhodactis howesii associated with a long line vessel that wrecked in 1991 on an isolated atoll (Palmyra) in the central Pacific Ocean. We documented high densities of R. howesii near the ship that progressively decreased with distance from the ship whereas R. howesii were rare to absent in other parts of the atoll. We also confirmed high densities of R. howesii around several buoys recently installed on the atoll in 2001. This is the first time that a phase shift on a coral reef has been unambiguously associated with man-made structures. This association was made, in part, because of the remoteness of Palmyra and its recent history of minimal human habitation or impact. Phase shifts can have long-term negative ramification for coral reefs, and eradication of organisms responsible for phase shifts in marine ecosystems can be difficult, particularly if such organisms cover a large area. The extensive R. howesii invasion and subsequent loss of coral reef habitat at Palmyra also highlights the importance of rapid removal of shipwrecks on corals reefs to mitigate the potential of reef overgrowth by invasives

    Prognostic indices in diffuse large B-cell lymphoma in the rituximab era: an analysis of the UK National Cancer Research Institute R-CHOP 14 versus 21 phase 3 trial

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    We compared the International Prognostic Index (IPI), Revised (R)‐IPI and age‐adjusted (aa)‐IPI as prognostic indices for patients with diffuse large B‐cell lymphoma (DLBCL) in the UK National Cancer Research Institute (NCRI) R‐CHOP 14 versus 21 trial (N = 1080). The R‐IPI and aa‐IPI showed no marked improvement compared to the IPI for overall and progression‐free survival, in terms of model fit or discrimination. Similar results were observed in exploratory analyses incorporating the Grupo Español de Linfomas/Transplante de Médula Ósea (GELTAMO)‐IPI, where baseline β2‐microglobulin data were available (N = 655). Although our findings support current use of the IPI, a novel prognostic tool to better delineate a high‐risk DLBCL group in the rituximab era is needed

    Submarine Fernandina : magmatism at the leading edge of the Galapagos hot spot

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    Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 7 (2006): Q12007, doi:10.1029/2006GC001290.New multibeam and side-scan sonar surveys of Fernandina volcano and the geochemistry of lavas provide clues to the structural and magmatic development of Galápagos volcanoes. Submarine Fernandina has three well-developed rift zones, whereas the subaerial edifice has circumferential fissures associated with a large summit caldera and diffuse radial fissures on the lower slopes. Rift zone development is controlled by changes in deviatoric stresses with increasing distance from the caldera. Large lava flows are present on the gently sloping and deep seafloor west of Fernandina. Fernandina's submarine lavas are petrographically more diverse than the subaerial suite and include picrites. Most submarine glasses are similar in composition to aphyric subaerially erupted lavas, however. These rocks are termed the “normal” series and are believed to result from cooling and crystallization in the subcaldera magma system, which buffers the magmas both thermally and chemically. These normal-series magmas are extruded laterally through the flanks of the volcano, where they scavenge and disaggregate olivine-gabbro mush to produce picritic lavas. A suite of lavas recovered from the terminus of the SW submarine rift and terraces to the south comprises evolved basalts and icelandites with MgO = 3.1 to 5.0 wt.%. This “evolved series” is believed to form by fractional crystallization at 3 to 5 kb, involving extensive crystallization of clinopyroxene and titanomagnetite in addition to plagioclase. “High-K” lavas were recovered from the southwest rift and are attributed to hybridization between normal-series basalt and evolved-series magma. The geochemical and structural findings are used to develop an evolutionary model for the construction of the Galápagos Platform and better understand the petrogenesis of the erupted lavas. The earliest stage is represented by the deep-water lava flows, which over time construct a broad submarine platform. The deep-water lavas originate from the subcaldera plumbing system of the adjacent volcano. After construction of the platform, eruptions focus to a point source, building an island with rift zones extending away from the adjacent, buttressing volcanoes. Most rift zone magmas intrude laterally from the subcaldera magma chamber, although a few evolve by crystallization in the upper mantle and deep crust.This work was supported by the National Science Foundation grants OCE0002818 and EAR0207605 (D.G.), OCE0002461 (D.J.F. and M.K.), OCE9811504 (D.J.F. and M.R.P.), and EAR0207425 (K.H.) and WHOI postdoctoral support for Soule

    Transforming Obesity Prevention for CHILDren (TOPCHILD) Collaboration: Protocol for a Systematic Review with Individual Participant Data Meta-Analysis of Behavioural Interventions for the Prevention of Early Childhood Obesity

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    INTRODUCTION: Behavioural interventions in early life appear to show some effect in reducing childhood overweight and obesity. However, uncertainty remains regarding their overall effectiveness, and whether effectiveness differs among key subgroups. These evidence gaps have prompted an increase in very early childhood obesity prevention trials worldwide. Combining the individual participant data (IPD) from these trials will enhance statistical power to determine overall effectiveness and enable examination of individual and trial-level subgroups. We present a protocol for a systematic review with IPD meta-analysis to evaluate the effectiveness of obesity prevention interventions commencing antenatally or in the first year after birth, and to explore whether there are differential effects among key subgroups. METHODS AND ANALYSIS: Systematic searches of Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycInfo and trial registries for all ongoing and completed randomised controlled trials evaluating behavioural interventions for the prevention of early childhood obesity have been completed up to March 2021 and will be updated annually to include additional trials. Eligible trialists will be asked to share their IPD; if unavailable, aggregate data will be used where possible. An IPD meta-analysis and a nested prospective meta-analysis will be performed using methodologies recommended by the Cochrane Collaboration. The primary outcome will be body mass index z-score at age 24±6 months using WHO Growth Standards, and effect differences will be explored among prespecified individual and trial-level subgroups. Secondary outcomes include other child weight-related measures, infant feeding, dietary intake, physical activity, sedentary behaviours, sleep, parenting measures and adverse events. ETHICS AND DISSEMINATION: Approved by The University of Sydney Human Research Ethics Committee (2020/273) and Flinders University Social and Behavioural Research Ethics Committee (HREC CIA2133-1). Results will be relevant to clinicians, child health services, researchers, policy-makers and families, and will be disseminated via publications, presentations and media releases. PROSPERO REGISTRATION NUMBER: CRD42020177408
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