The contribution of massive haloes to the matter power spectrum in the presence of AGN feedback

The clustering of matter, as measured by the matter power spectrum, informs us about dark matter and cosmology, as well as baryonic effects on the distribution of matter in the universe. Using cosmological hydrodynamical simulations from the cosmo-OWLS and BAHAMAS simulation projects, we investigate the contribution of power in haloes with various masses, defined by particles within some overdensity region, to the full power spectrum, as well as the power ratio between baryonic and dark matter only (DMO) simulations for a matched (between simulations) and an unmatched set of haloes. We find that the presence of AGN feedback suppresses the power on all scales for haloes of all masses examined ($10^{11.25}\leq M_{500,\mathrm{crit}}\leq 10^{14.75}\,\mathrm{M_\odot}/h$), by ejecting matter from within $r_{500,\mathrm{c}}$ to $r_{200,\mathrm{m}}$ and potentially beyond in massive haloes ($M_{500,\mathrm{crit}}\gtrsim 10^{13}\,\mathrm{M_\odot}/h$), and likely impeding the growth of lower-mass haloes as a consequence. A lower AGN feedback temperature drastically changes the behaviour of high-mass haloes ($M_{500,\mathrm{crit}}\geq 10^{13.25}\,\mathrm{M_\odot}/h$), damping the effects of AGN feedback at small scales, $k\,\gtrsim\,4\,h\mathrm{\,Mpc^{-1}}$. For $k\,\lesssim\,3\,h\mathrm{\,Mpc^{-1}}$, group-sized haloes ($10^{14\pm0.25}\, \mathrm{M_\odot}/h$) dominate the power spectrum, while on smaller scales the combined contributions of lower-mass haloes to the full power spectrum rise above that of the group-sized haloes. Finally, we present a model for the power suppression due to feedback, which combines observed mean halo baryon fractions with halo mass fractions and halo-matter cross-spectra extracted from dark matter only simulations to predict the power suppression to percent-level accuracy down to $k\,\approx\,10\,h\mathrm{\,Mpc^{-1}}$ without any free parameters.Comment: 20 pages, 11 figures. Submitted to MNRA

Anti-aphrodisiac Compounds of Male Butterflies Increase the Risk of Egg Parasitoid Attack by Inducing Plant Synomone Production

During mating in many butterfly species, males transfer spermatophores that contain anti-aphrodisiacs to females that repel conspecific males. For example, males of the large cabbage white, Pieris brassicae (Lepidoptera: Pieridae), transfer the anti-aphrodisiac, benzyl cyanide (BC) to females. Accessory reproductive gland (ARG) secretion of a mated female P. brassicae that is deposited with an egg clutch contains traces of BC, inducing Brussels sprouts plants (Brassica oleracea var. gemmifera) to arrest certain Trichogramma egg parasitoids. Here, we assessed whether deposition of one egg at a time by the closely related small cabbage white, Pieris rapae, induced B. oleracea var. gemmifera to arrest Trichogramma wasps, and whether this plant synomone is triggered by substances originating from male P. rapae seminal fluid. We showed that plants induced by singly laid eggs of P. rapae arrest T. brassicae wasps three days after butterfly egg deposition. Elicitor activity was present in ARG secretion of mated female butterflies, whereas the secretion of virgin females was inactive. Pieris rapae used a mixture of methyl salicylate (MeSA) and indole as an anti-aphrodisiac. We detected traces of both anti-aphrodisiacal compounds in the ARG secretion of mated female P. rapae, whereas indole was lacking in the secretion of virgin female P. rapae. When applied onto the leaf, indole induced changes in the foliar chemistry that arrested T. brassicae wasps. This study shows that compounds of male seminal fluid incur possible fitness costs for Pieris butterflies by indirectly promoting egg parasitoid attack

Ingestion of free amino acids compared with an equivalent amount of intact protein results in more rapid amino acid absorption and greater postprandial plasma amino acid availability without affecting muscle protein synthesis rates in young adults in a double-blind randomized trial

Background The rate of protein digestion and amino acid absorption determines the postprandial rise in circulating amino acids and modulates postprandial muscle protein synthesis rates. Objective We sought to compare protein digestion, amino acid absorption kinetics, and the postprandial muscle protein synthetic response following ingestion of intact milk protein or an equivalent amount of free amino acids. Methods Twenty-four healthy, young participants (mean ± SD age: 22 ± 3 y and BMI 23 ± 2 kg/m2; sex: 12 male and 12 female participants) received a primed continuous infusion of l-[ring-2H5]-phenylalanine and l-[ring-3,5–2H2]-tyrosine, after which they ingested either 30 g intrinsically l-[1–13C]-phenylalanine–labeled milk protein or an equivalent amount of free amino acids labeled with l-[1–13C]-phenylalanine. Blood samples and muscle biopsies were obtained to assess protein digestion and amino acid absorption kinetics (secondary outcome), whole-body protein net balance (secondary outcome), and mixed muscle protein synthesis rates (primary outcome) throughout the 6-h postprandial period. Results Postprandial plasma amino acid concentrations increased after ingestion of intact milk protein and free amino acids (both P < 0.001), with a greater increase following ingestion of the free amino acids than following ingestion of intact milk protein (P-time × treatment < 0.001). Exogenous phenylalanine release into plasma, assessed over the 6-h postprandial period, was greater with free amino acid ingestion (76 ± 9%) than with milk protein treatment (59 ± 10%; P < 0.001). Ingestion of free amino acids and intact milk protein increased mixed muscle protein synthesis rates (P-time < 0.001), with no differences between treatments (from 0.037 ± 0.015%/h to 0.053 ± 0.014%/h and 0.039 ± 0.016%/h to 0.051 ± 0.010%/h, respectively; P-time × treatment = 0.629). Conclusions Ingestion of a bolus of free amino acids leads to more rapid amino acid absorption and greater postprandial plasma amino acid availability than ingestion of an equivalent amount of intact milk protein. Ingestion of free amino acids may be preferred over ingestion of intact protein in conditions where protein digestion and amino acid absorption are compromised

Agents united:An open platform for multi-agent conversational systems

The development of applications with intelligent virtual agents (IVA) often comes with integration of multiple complex components. In this article we present the Agents United Platform: an open source platform that researchers and developers can use as a starting point to setup their own multi-IVA applications. The new platform provides developers with a set of integrated components in a sense-remember-think-act architecture. Integrated components are a sensor framework, memory component, Topic Selection Engine, interaction manager (Flipper), two dialogue execution engines, and two behaviour realisers (ASAP and GRETA) of which the agents can seamlessly interact with each other. This article discusses the platform and its individual components. It also highlights some of the novelties that arise from the integration of components and elaborates on directions for future work

Jasmonic Acid-Induced Changes in Brassica oleracea Affect Oviposition Preference of Two Specialist Herbivores

Jasmonic acid (JA) is a key hormone involved in plant defense responses. The effect of JA treatment of cabbage plants on their acceptability for oviposition by two species of cabbage white butterflies, Pieris rapae and P. brassicae, was investigated. Both butterfly species laid fewer eggs on leaves of JA-treated plants compared to control plants. We show that this is due to processes in the plant after JA treatment rather than an effect of JA itself. The oviposition preference for control plants is adaptive, as development time from larval hatch until pupation of P. rapae caterpillars was longer on JA-treated plants. Total glucosinolate content in leaf surface extracts was similar for control and treated plants; however, two of the five glucosinolates were present in lower amounts in leaf surface extracts of JA-treated plants. When the butterflies were offered a choice between the purified glucosinolate fraction isolated from leaf surface extracts of JA-treated plants and that from control plants, they did not discriminate. Changes in leaf surface glucosinolate profile, therefore, do not seem to explain the change in oviposition preference of the butterflies after JA treatment, suggesting that as yet unknown infochemicals are involved

Differential gene expression in nearly isogenic lines with QTL for partial resistance to Puccinia hordei in barley

<p>Abstract</p> <p>Background</p> <p>The barley-<it>Puccinia hordei </it>(barley leaf rust) pathosystem is a model for investigating partial disease resistance in crop plants and genetic mapping of phenotypic resistance has identified several quantitative trait loci (QTL) for partial resistance. Reciprocal QTL-specific near-isogenic lines (QTL-NILs) have been developed that combine two QTL, <it>Rphq</it>2 and <it>Rphq</it>3, the largest effects detected in a recombinant-inbred-line (RIL) population derived from a cross between the super-susceptible line L94 and partially-resistant line Vada. The molecular mechanism underpinning partial resistance in these QTL-NILs is unknown.</p> <p>Results</p> <p>An Agilent custom microarray consisting of 15,000 probes derived from barley consensus EST sequences was used to investigate genome-wide and QTL-specific differential expression of genes 18 hours post-inoculation (hpi) with <it>Puccinia hordei</it>. A total of 1,410 genes were identified as being significantly differentially expressed across the genome, of which 55 were accounted for by the genetic differences defined by QTL-NILs at <it>Rphq</it>2 and <it>Rphq</it>3. These genes were predominantly located at the QTL regions and are, therefore, positional candidates. One gene, encoding the transcriptional repressor Ethylene-Responsive Element Binding Factor 4 (<it>HvERF4</it>) was located outside the QTL at 71 cM on chromosome 1H, within a previously detected eQTL hotspot for defence response. The results indicate that <it>Rphq</it>2 or <it>Rphq</it>3 contains a <it>trans</it>-eQTL that modulates expression of <it>HvERF4</it>. We speculate that HvERF4 functions as an intermediate that conveys the response signal from a gene(s) contained within <it>Rphq</it>2 or <it>Rphq</it>3 to a host of down-stream defense responsive genes. Our results also reveal that barley lines with extreme or intermediate partial resistance phenotypes exhibit a profound similarity in their spectrum of <it>Ph</it>-responsive genes and that hormone-related signalling pathways are actively involved in response to <it>Puccinia hordei</it>.</p> <p>Conclusions</p> <p>Differential gene expression between QTL-NILs identifies genes predominantly located within the target region(s) providing both transcriptional and positional candidate genes for the QTL. Genetically mapping the differentially expressed genes relative to the QTL has the potential to discover <it>trans</it>-eQTL mediated regulatory relays initiated from genes within the QTL regions.</p

Herbivore-Mediated Effects of Glucosinolates on Different Natural Enemies of a Specialist Aphid

The cabbage aphid Brevicoryne brassicae is a specialist herbivore that sequesters glucosinolates from its host plant as a defense against its predators. It is unknown to what extent parasitoids are affected by this sequestration. We investigated herbivore-mediated effects of glucosinolates on the parasitoid wasp Diaeretiella rapae and the predator Episyrphus balteatus. We reared B. brassicae on three ecotypes of Arabidopsis thaliana that differ in glucosinolate content and on one genetically transformed line with modified concentrations of aliphatic glucosinolates. We tested aphid performance and the performance and behavior of both natural enemies. We correlated this with phloem and aphid glucosinolate concentrations and emission of volatiles. Brevicoryne brassicae performance correlated positively with concentrations of both aliphatic and indole glucosinolates in the phloem. Aphids selectively sequestered glucosinolates. Glucosinolate concentration in B. brassicae correlated negatively with performance of the predator, but positively with performance of the parasitoid, possibly because the aphids with the highest glucosinolate concentrations had a higher body weight. Both natural enemies showed a positive performance-preference correlation. The predator preferred the ecotype with the lowest emission of volatile glucosinolate breakdown products in each test combination, whereas the parasitoid wasp preferred the A. thaliana ecotype with the highest emission of these volatiles. The study shows that there are differential herbivore-mediated effects of glucosinolates on a predator and a parasitoid of a specialist aphid that selectively sequesters glucosinolates from its host plant