223 research outputs found
Intrinsic competition and its effects on the survival and development of three species of endoparasitoid wasps
In natural systems, pre-adult stages of some insect herbivores are known to be attacked by several species of parasitoids. Under certain conditions, hosts may be simultaneously parasitized by more than one parasitoid species (= multiparasitism), even though only one parasitoid species can successfully develop in an individual host. Here, we compared development, survival, and intrinsic competitive interactions among three species of solitary larval endoparasitoids, Campoletis sonorensis (Cameron) (Hymenoptera: Ichneumonidae), Microplitis demolitor Wilkinson, and Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), in singly parasitized and multiparasitized hosts. The three species differed in certain traits, such as in host usage strategies and adult body size. Campoletis sonorensis and M. demolitor survived equally well to eclosion in two host species that differed profoundly in size, Pseudoplusia includens (Walker) and the larger Heliothis virescens (Fabricius) (both Lepidoptera: Noctuidae). Egg-to-adult development time in C. sonorensis and M. demolitor also differed in the two hosts. Moreover, adult body mass in C. sonorensis (and not M. demolitor) was greater when developing in H. virescens larvae. We then monitored the outcome of competitive interactions in host larvae that were parasitized by one parasitoid species and subsequently multiparasitized by another species at various time intervals (0, 6, 24, and 48 h) after the initial parasitism. These experiments revealed that M. croceipes was generally a superior competitor to the other two species, whereas M. demolitor was the poorest competitor, with C. sonorensis being intermediate in this capacity. However, competition sometimes incurred fitness costs in M. croceipes and C. sonorensis, with longer development time and/or smaller adult mass observed in surviving wasps emerging from multiparasitized hosts. Our results suggest that rapid growth and large size relative to competitors of a similar age may be beneficial in aggressive intrinsic competitio
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Ecological fate and effects of solvent-refined-coal (SRC) materials: a status report
Non-occupational health effects associated with SRC operation will be determined by environmental factors governing the form, transport, and persistence of SRC materials and wastes - factors which also mediate exposure to man. Accordingly, the research described is an attempt to determine the fate of disposed solid wastes and spilled SRC materials, and it necessarily focuses on water soluble, persistent materials with greatest potential for mobility and incorporation into water and food supplies. Initially, aqueous equilibrations of SRC-II liquid material and SRC-I nongasified mineral residue were subjected to chemical characterization. Subsequently, laboratory studies were performed on the interaction of aqueous equilibrates of SRC-II liquid and SRC-I non-gasified mineral residue with soil materials isolated suspended sediments, and bottom sediments. These studies were designed to identify effects of specific sorption reactions ion or induced-ion exchange reactions, and toxicity of water soluble, biologically active materials derived from liquid and solid wastes. Results of these experiments have applicability to the environmental fate and effects of biologically active compounds released under different scenarios from product spills and solid waste disposal
Tradeoffs and synergies in wetland multifunctionality: A scaling issue
Wetland area in agricultural landscapes has been heavily reduced to gain land for crop production, but in recent years there is increased societal recognition of the negative consequences from wetland loss on nutrient retention, biodiversity and a range of other benefits to humans. The current trend is therefore to re-establish wetlands, often with an aim to achieve the simultaneous delivery of multiple ecosystem services, i.e., multifunctionality. Here we review the literature on key objectives used to motivate wetland re-establishment in temperate agricultural landscapes (provision of flow regulation, nutrient retention, climate mitigation, biodiversity conservation and cultural ecosystem services), and their relationships to environmental properties, in order to identify potential for tradeoffs and synergies concerning the development of multifunctional wetlands. Through this process, we find that there is a need for a change in scale from a focus on single wetlands to wetlandscapes (multiple neighboring wetlands including their catchments and surrounding landscape features) if multiple societal and environmental goals are to be achieved. Finally, we discuss the key factors to be considered when planning for re-establishment of wetlands that can support achievement of a wide range of objectives at the landscape scale
Search for the decay in the momentum region
We have searched for the decay in the kinematic
region with pion momentum below the peak. One event was
observed, consistent with the background estimate of . This
implies an upper limit on
(90% C.L.), consistent with the recently measured branching ratio of
, obtained using the standard model
spectrum and the kinematic region above the peak. The
same data were used to search for , where is a weakly
interacting neutral particle or system of particles with .Comment: 4 pages, 2 figure
Search for the decay K+ to pi+ gamma gamma in the pi+ momentum region P>213 MeV/c
We have searched for the K+ to pi+ gamma gamma decay in the kinematic region
with pi+ momentum close to the end point. No events were observed, and the 90%
confidence-level upper limit on the partial branching ratio was obtained, B(K+
to pi+ gamma gamma, P>213 MeV/c) < 8.3 x 10-9 under the assumption of chiral
perturbation theory including next-to-leading order ``unitarity'' corrections.
The same data were used to determine an upper limit on the K+ to pi+ gamma
branching ratio of 2.3 x 10-9 at the 90% confidence level.Comment: 15 pages, 3 figures; no change in the results, accepted for
publication in Physics Letters
Improvement of functioning and health with ixekizumab in the treatment of active nonradiographic axial spondyloarthritis in a 52-week, randomized, controlled trial
Objective To evaluate the effect of ixekizumab on self-reported functioning and health in patients with active nonradiographic axial spondyloarthritis (SpA). Methods COAST-X was a randomized, controlled trial conducted in patients with nonradiographic axial SpA over 52 weeks. Participants were randomized at a ratio of 1:1:1 to receive 80 mg of ixekizumab subcutaneously every 4 weeks or 2 weeks or placebo for 52 weeks. Self-reported functioning and health end points included the Medical Outcomes Study Short Form 36 (SF-36) health survey, Assessment of Spondyloarthritis International Society (ASAS) health index, and European Quality of Life-5 Dimensions-5 Level (EQ-5D-5L) health-utility descriptive system. Results Compared to placebo, ixekizumab treatment resulted in improvement of SF-36 physical component summary scores from baseline, with a score of 4.7 improving to 8.9 with ixekizumab therapy every 4 weeks (P = 3 improvements based on the ASAS health index from baseline to weeks 16 and 52 (P < 0.05). Significantly more patients receiving ixekizumab every 4 weeks reported improvements in "good health status" on the ASAS health index (ASAS score of <= 5) at weeks 16 and 52 (P < 0.05). Patients receiving ixekizumab reported improvements on the EQ-5D-5L compared to those who received placebo at week 16 (0.11 versus 0.17 for patients receiving treatment every 4 weeks and 0.19 for patients receiving treatment every 2 weeks; P < 0.05), which remained consistent at week 52. There were no clinical meaningful differences in responses based on the ixekizumab dosing regimen for patients who received ixekizumab therapy every 2 weeks or every 4 weeks. Conclusion In patients with nonradiographic axial SpA, therapy with ixekizumab was superior to placebo in the improvement of self-reported functioning and health at weeks 16 and 52.Pathophysiology and treatment of rheumatic disease
Reduced use of illicit substances, even without abstinence, is associated with improved depressive symptoms among people living with HIV
Purpose: Substance use is linked with poor outcomes among people living with HIV (PLWH) and is associated with mental health disorders. This analysis examines the impact of decreasing substance use, even without abstinence, on depressive symptoms among PLWH. Methods: Data are from PLWH enrolled in the Centers for AIDS Research Network of Integrated Clinical Sites cohort. Participants completed longitudinal assessments of substance use (modified ASSIST) and depressive symptoms (PHQ-9). Changes in substance use frequency were categorized as abstinence, reduced use, and nondecreasing use. Adjusted linear mixed models with time-updated change in substance use frequency and depressive symptom scores were used to examine associations between changes in the use of individual substances and depressive symptoms. Analyses were repeated using joint longitudinal survival models to examine associations with a high (PHQ-9 ≥10) score. Results: Among 9905 PLWH, 728 used cocaine/crack, 1016 used amphetamine-type substances (ATS), 290 used illicit opiates, and 3277 used marijuana at baseline. Changes in ATS use were associated with the greatest improvements in depressive symptoms: stopping ATS led to a mean decrease of PHQ-9 by 2.2 points (95% CI: 1.8 to 2.7) and a 61% lower odds of PHQ-9 score ≥10 (95% CI: 0.30 to 0.52), and decreasing ATS use led to a mean decrease of 1.7 points (95% CI: 1.2 to 2.3) and a 62% lower odds of PHQ-9 score ≥10 (95% CI: 0.25 to 0.56). Stopping and reducing marijuana and stopping cocaine/crack use were also associated with improvement in depressive symptoms. Conclusions: We demonstrated that both substance use reduction and abstinence are associated with improvements in depressive symptoms over time
Further search for the decay in the momentum region P < 195 MeV/c
We report the results of a search for the decay
in the kinematic region with momentum MeV/c using the
data collected by the E787 experiment at BNL. No events were observed. When
combined with our previous search in this region, one candidate event with an
expected background of events results in a 90% C.L. upper limit
of on the branching ratio of .
We also report improved limits on the rates of and where are hypothetical, massless, long-lived
neutral particles.Comment: 5 pages, 3 figures, Accepted for publication in Phys. Rev.
Hadronic contributions to of the leptons and to the effective fine structure constant
The hadronic contributions to the anomalous magnetic moments of the leptons
and to the effective fine structure constant at the Z-mass are reevaluated
using all presently available data.Comment: 36 pages, 11 Postscript figures, available at
ftp://129.129.40.58/pub/preprints/vapogm2.ps.g
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