664 research outputs found
Effects of an entomopathogenic fungus on the reproductive potential of Drosophila males.
While mortality is often the primary focus of pathogen virulence, non-lethal consequences, particularly for male reproductive fitness, are less understood; however, they are essential for understanding how sexual selection contributes to promoting resistance. We investigated how the fungal pathogen Metarhizium brunneum affects mating ability, fertility, and seminal fluid protein (SFP) expression of male Drosophila melanogaster paired with highly receptive virgin females in non-competitive settings. Depending on sex and dose, there was a 3-6-day incubation period after infection, followed by an abrupt onset of mortality. Meanwhile, the immune response was strongly induced already 38 h after infection and continued to increase as infection progressed. Latency to mate somewhat increased during the incubation period compared to sham-treated males, but even on Day 5 post infection >90% of infected males mated within 2 h. During the incubation period, M. brunneum infection reduced male reproductive potential (the number of offspring sired without mate limitation) by 11%, with no clear increase over time. Approaching the end of the incubation period, infected males had lower ability to convert number of mating opportunities into number of offspring. After repeated mating, infected males had lower SFP expression than sham controls, more so in males that mated with few mates 24 h earlier. Overall, despite strong activation of the immune response, males' mating ability and fertility remained surprisingly little affected by the fungal infection, even shortly before the onset of mortality. This suggests that the selection for resistance acts mainly through mortality, and the scope for fertility selection to enhance resistance in non-competing settings is rather limited
Simultaneous Determination of Human Plasma Levels of Citalopram, Paroxetine, Sertraline, and Their Metabolites by Gas Chromatography—Mass Spectrometry
A gas chromatography—mass spectrometry method is presented which allows the simultaneous determination of the plasma concentrations of the selective serotonin reuptake inhibitors citalopram, paroxetine, sertraline, and their pharmacologically active N-demethylated metabolites (desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline) after derivatization with the reagent N-methyl-bis(trifluoroacetamide). No interferences from endogenous compounds are observed following the extraction of plasma samples from six different human subjects. The standard curves are linear over a working range of 10-500 ng/mL for citalopram, 10-300 ng/mL for desmethylcitalopram, 5-60 ng/mL for didesmethylcitalopram, 20-400 ng/mL for sertraline and desmethylsertraline, and 10-200 ng/mL for paroxetine. Recoveries measured at three concentrations range from 81 to 118% for the tertiary amines (citalopram and the internal standard methylmaprotiline), 73 to 95% for the secondary amines (desmethylcitalopram, paroxetine and sertraline), and 39 to 66% for the primary amines (didesmethylcitalopram and desmethylsertraline). Intra- and interday coefficients of variation determined at three concentrations range from 3 to 11 % for citalopram and its metabolites, 4 to 15% for paroxetine, and 5 to 13% for sertraline and desmethylsertraline. The limits of quantitation of the method are 2 ng/mL for citalopram and paroxetine, 1 ng/mL for sertraline, and 0.5 ng/mL for desmethylcitalopram, didesmethylcitalopram, and desmethylsertraline. No interferences are noted from 20 other psychotropic drugs. This sensitive and specific method can be used for single-dose pharmacokinetics. It is also useful for therapeutic drug monitoring of these three drugs and could possibly be adapted for the quantitation of the two other selective serotonin reuptake inhibitors on the market, namely fluoxetine and fluvoxamin
Optimization of the Even Normal Multipole Components in the Main Dipole of the Large Hadron Collider
In this paper we discuss even multipolar components of the Large Hadron Collider dipole in relation to the manufacturing features and target values required by beam dynamics. Due to the two-in-one collar geometry, systematic components are induced by the mutual influence of the two apertures and are strongly affected by the shape of the magnetic iron yoke. In order to optimize the normal quadrupole and octupole harmonics, a new design was chosen for the ferromagnetic insert between the iron yoke and the collars. Three different insert shapes were selected and installed in a full scale prototype. The measured dependence of the even multipoles on the insert shape shows a good agreement with simulations based on a magnetostatic code. A final design of the insert has been worked out and implemented in pre-series magnets. Data relative to even multipoles in pre-series magnets are presented, both at room temperature and at the operational temperature of 1.9 K. Comparison with target values required by beam dynamics is discussed
People making deontological judgments in the Trapdoor dilemma are perceived to be more prosocial in economic games than they actually are
Why do people make deontological decisions, although they often lead to overall unfavorable outcomes? One account is receiving considerable attention: deontological judgments may signal commitment to prosociality and thus may increase people’s chances of being selected as social partners–which carries obvious long-term benefits. Here we test this framework by experimentally exploring whether people making deontological judgments are expected to be more prosocial than those making consequentialist judgments and whether they are actually so. In line with previous studies, we identified deontological choices using the Trapdoor dilemma. Using economic games, we take two measures of general prosociality towards strangers: trustworthiness and altruism. Our results procure converging evidence for a perception gap according to which Trapdoor-deontologists are believed to be more trustworthy and more altruistic towards strangers than Trapdoor-consequentialists, but actually they are not so. These results show that deontological judgments are not universal, reliable signals of prosociality
Stocking activities for the Arctic charr in Lake Geneva: Genetic effects in space and time
Artificial stocking practices are widely used by resource managers worldwide, in order
to sustain fish populations exploited by both recreational and commercial activities,
but their benefits are controversial. Former practices involved exotic strains, although
current programs rather consider artificial breeding of local fishes (supportive breeding).
Understanding the complex genetic effects of these management strategies is an
importan t challenge with economic and conservation implications, especially in the
context of population declines. In this study, we focus on the declining Arctic charr
(Salvelinus alpinus) population from Lake Geneva (Switzerland and France), which has
initially been restocked with allochtonous fishes in the early eighties, followed by supportive
breeding. In this context, we conducted a genetic survey to document the
evolution of the genetic diversity and structure throughout the last 50 years, before
and after the initiation of hatchery supplementation, using contemporary and historical
samples. We show that the introduction of exotic fishes was associated with a genetic
bottleneck in the 1980–1990s, a break of Hardy–Weinberg Equilibrium (HWE),
a reduction in genetic diversity, an increase in genetic structure among spawning sites,
and a change in their genetic composition. Together with better environmental conditions,
three decades of subsequent supportive breeding using local fishes allowed to
re-establish HWE and the initial levels of genetic variation. However, current spawning
sites have not fully recovered their original genetic composition and were extensively
h omogenized across the lake. Our study demonstrates the drastic genetic
consequ e nces of different restocking tactics in a comprehensive spatiotemporal
framewo rk and suggests that genetic alteration by nonlocal stocking may be partly
reversible through supportive breeding. We recommend that conservation-based programs
consider local diversity and implement adequate protocols to limit the genetic
homogenization of this Arctic charr population
Design, Manufacturing Aspects and Performance of Recent 10 m Long Model Dipole Superconducting Magnets for the LHC Project
A number of twin aperture, 10 m long, model dipole magnets for the LHC Project have been built and tested. With regard to the models of the first generation, the inner coil diameter and the intra-beam distance were increased from 50 to 56 mm and from 180 to about 194 mm, respectively. Also with regard to the previous models, a 5-block (instead of a 6-block) coil cross-section was chosen and the wid th of the Rutherford cable was reduced from 17 mm to 15 mm. The coils were manufactured and collared in Industry, the assembly of their magnetic circuit and cold mass were carried out at CERN. The ind ividual design and manufacturing features of each of these magnets are described and the results of their warm and cold magnetic measurement are presented and discussed
Within-species phylogenetic relatedness of a common mycorrhizal fungus affects evenness in plant communities through effects on dominant species.
Arbuscular mycorrhizal fungi (AMF) have been shown to influence plant community structure and diversity. Studies based on single plant-single AMF isolate experiments show that within AMF species variation leads to large differential growth responses of different plant species. Because of these differential effects, genetic differences among isolates of an AMF species could potentially have strong effects on the structure of plant communities. We tested the hypothesis that within species variation in the AMF Rhizophagus irregularis significantly affects plant community structure and plant co-existence. We took advantage of a recent genetic characterization of several isolates using double-digest restriction-site associated DNA sequencing (ddRADseq). This allowed us to test not only for the impact of within AMF species variation on plant community structure but also for the role of the R. irregularis phylogeny on plant community metrics. Nine isolates of R. irregularis, belonging to three different genetic groups (Gp1, Gp3 and Gp4), were used as either single inoculum or as mixed diversity inoculum. Plants in a mesocosm representing common species that naturally co-exist in European grasslands were inoculated with the different AMF treatments. We found that within-species differences in R. irregularis did not strongly influence the performance of individual plants or the structure of the overall plant community. However, the evenness of the plant community was affected by the phylogeny of the fungal isolates, where more closely-related AMF isolates were more likely to affect plant community evenness in a similar way compared to more genetically distant isolates. This study underlines the effect of within AMF species variability on plant community structure. While differential effects of the AMF isolates were not strong, a single AMF species had enough functional variability to change the equilibrium of a plant community in a way that is associated with the evolutionary history of the fungus
People making deontological judgments in the Trapdoor dilemma are perceived to be more prosocial in economic games than they actually are
Why do people make deontological decisions, although they often lead to overall unfavorable outcomes? One account is receiving considerable attention: deontological judgments may signal commitment to prosociality and thus may increase people’s chances of being selected as social partners–which carries obvious long-term benefits. Here we test this framework by experimentally exploring whether people making deontological judgments are expected to be more prosocial than those making consequentialist judgments and whether they are actually so. In line with previous studies, we identified deontological choices using the Trapdoor dilemma. Using economic games, we take two measures of general prosociality towards strangers: trustworthiness and altruism. Our results procure converging evidence for a perception gap according to which Trapdoor-deontologists are believed to be more trustworthy and more altruistic towards strangers than Trapdoor-consequentialists, but actually they are not so. These results show that deontological judgments are not universal, reliable signals of prosociality
People making deontological judgments in the Trapdoor dilemma are perceived to be more prosocial in economic games than they actually are
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