Wall-pressure and velocity statistics in the turbulent boundary layer (TBL) on a cambered controlled-diffusion aerofoil at $8^{\circ }$ incidence, a Mach number of 0.25 and a chord-based Reynolds ...number ${Re}_c=1.5\times 10^{5}$ are analysed at four locations on the suction side with zero and adverse pressure gradients (ZPG and APG), characterised by increasing Reynolds numbers based on momentum thickness, ${Re}_{\theta }=319$, 390, 877 and $1036$. The strong APG yields a highly non-equilibrium TBL at the trailing edge that significantly affects the turbulent flow statistics. Different normalisations of the full wall-pressure statistics involved in trailing-edge noise are analysed for the first time in such strong APG with convex curvature, and compared with available experimental and numerical data. Good overall agreement is found in the ZPG region, and most results obtained in previous APG TBL can be extended to the present highly non-equilibrium case. The presence of strong APG augments the intensity of wall-pressure fluctuations noticeably at low frequencies, shortens the streamwise and broadens the spanwise coherence of wall-pressure fluctuations in both time and space, and significantly reduces the convection velocity. The wall-pressure power spectral density are found to scale with the displacement thickness, the Zaragola–Smits velocity and the root-mean-squared pressure, the latter possibly being replaced by the local maximum Reynolds shear stress. The other two key parameters to trailing-edge noise modelling, the spanwise coherence length and the convection velocity, rather scale with displacement thickness and friction velocity, respectively.
Endogenous viral elements (EVEs) can play a significant role in the evolution of their hosts and have been identified in animals, plants, and fungi. Additionally, EVEs potentially provide an ...important snapshot of the evolutionary frequency of viral infection. The purpose of this study is to take a comparative host-centered approach to EVE discovery in ant genomes to better understand the relationship of EVEs to their ant hosts. Using a comprehensive bioinformatic pipeline, we screened all nineteen published ant genomes for EVEs. Once the EVEs were identified, we assessed their phylogenetic relationships to other closely related exogenous viruses. A diverse group of EVEs were discovered in all screened ant host genomes and in many cases are similar to previously identified exogenous viruses. EVEs similar to ssRNA viral proteins are the most common viral lineage throughout the ant hosts, which is potentially due to more chronic infection or more effective endogenization of certain ssRNA viruses in ants. In addition, both EVEs similar to viral glycoproteins and retrovirus-derived proteins are also abundant throughout ant genomes, suggesting their tendency to endogenize. Several of these newly discovered EVEs are found to be potentially functional within the genome. The discovery and analysis of EVEs is essential in beginning to understand viral-ant interactions over evolutionary time.
EGFR mutations cause inconsistent response to EGFR tyrosine-kinase inhibitors (TKI). To better understand these features, we reviewed all cases of EGFR-mutated non-small-cell lung cancer collected in ...the Biomarkers France database.
Of 17664 patients, 1837 (11%) with EGFR-mutated non-small-cell lung cancer were retrospectively analyzed for clinical and molecular characteristics. Results were correlated with survival and treatment response for the 848 stage IV patients.
EGFR exon 18, 19, 20 and 21 mutations were found in 102 (5.5%), 931 (51%), 102 (5.5%) and 702 (38%) patients, respectively. Over 50% of exon 18 and 20 mutated patients were smokers. The median follow-up was 51.7months. EGFR mutation type was prognostic of overall survival (OS) versus wild-type {exon 19: hazard ratio (HR)=0.51 95% confidence interval (CI): 0.41–0.64, P < 0.0001; exon 21: HR= 0.76 (95% CI: 0.61–0.95), P = 0.002; exon 20: HR= 1.56 (95% CI: 1.02–2.38), P = 0.004}. EGFR mutation type was prognostic of progression-free survival versus wild-type exon 19: HR= 0.62 (95% CI: 0.49–0.78), P < 0.0001; exon 20: HR= 1.46 (95% CI: 0.96–2.21), P = 0.07. First-line treatment choice did not influence OS in multivariate analysis. First-line TKI predicted improved progression-free survival versus chemotherapy HR= 0.67 (95% CI: 0.53–0.85), P = 0.001. OS was longer for del19 versus L858R, which was associated with better OS compared with other exon 21 mutations, including L861Q. TKI improved survival in patients with exon 18 mutations, while chemotherapy was more beneficial for exon 20-mutated patients.
EGFR mutation type can inform the most appropriate treatment. Therapeutic schedule had no impact on OS in our study, although TKI should be prescribed in first-line considering the risk of missing the opportunity to use this treatment.
Among geophysical methods, the electrical resistivity tomography (ERT) method is one of the most commonly used for the study of hydrodynamical processes. The geophysical literature relates several ...laboratory-scale applications of this method. Unlike the measurements taken at the field scale, few authors have taken an interest in errors associated with apparent electrical resistivity, especially in the case of ERT data acquired in the laboratory. The objective of this paper is to show that laboratory errors related to the positioning of electrodes and the geometry of cells are significant on apparent resistivity measurements. The embedment and the position of the electrode were evaluated to quantify their impact on electrical resistivity measurement. To assess these impacts, the authors propose a 3D numerical modelling investigation based on the complete design of a laboratory test cell.
•Guidelines to design laboratory ERT measurements.•Numerical approch based on full 3D complete electrode modelling evaluation of ERT errors.•Evaluation of laboratory errors related to the positioning of electrodes and the geometry of cells.•For laboratory applications, we demonstrate that the impact of electrode diameter is negligible.
Symbiotic bacteria play important roles in the biology of their arthropod hosts. Yet the microbiota of many diverse and influential groups remain understudied, resulting in a paucity of information ...on the fidelities and histories of these associations. Motivated by prior findings from a smaller scale, 16S rRNA‐based study, we conducted a broad phylogenetic and geographic survey of microbial communities in the ecologically dominant New World army ants (Formicidae: Dorylinae). Amplicon sequencing of the 16S rRNA gene across 28 species spanning the five New World genera showed that the microbial communities of army ants consist of very few common and abundant bacterial species. The two most abundant microbes, referred to as Unclassified Firmicutes and Unclassified Entomoplasmatales, appear to be specialized army ant associates that dominate microbial communities in the gut lumen of three host genera, Eciton, Labidus and Nomamyrmex. Both are present in other army ant genera, including those from the Old World, suggesting that army ant symbioses date back to the Cretaceous. Extensive sequencing of bacterial protein‐coding genes revealed multiple strains of these symbionts coexisting within colonies, but seldom within the same individual ant. Bacterial strains formed multiple host species‐specific lineages on phylogenies, which often grouped strains from distant geographic locations. These patterns deviate from those seen in other social insects and raise intriguing questions about the influence of army ant colony swarm‐founding and within‐colony genetic diversity on strain coexistence, and the effects of hosting a diverse suite of symbiont strains on colony ecology.
An analytical model of the broadband noise produced by both the interaction of ingested turbulence with a fan rotor blades and the rotor-wake impingement on downstream stator vanes is proposed and ...detailed. The noise prediction methodology is a strip-theory approach based on a previously published formulation of the three-dimensional unsteady blade loading for a rectilinear cascade. This three-dimensional cascade response applied in each strip combined with an acoustic analogy in an annular duct have been chosen to account for the main three-dimensional effects. To further improve some of the identified limitations of this approach, a correction is added to mitigate the effects of the non-coincidence of the cut-on frequencies of the annular duct modes and of the modes of the rectilinear cascade. A correction of the unsteady blade loading formulation, previously developed in a tonal configuration, is also introduced to account for the dispersion relation of annular duct modes in the rectilinear-cascade model. The model is compared with experimental results of the 22-in source diagnostic test (SDT) fan rig of the NASA Glenn Research Center. A numerical assessment of the simplifications proposed in the model and of the convergence of the truncated sums in spanwise wavenumbers and azimuthal orders of the incident perturbation is carried out. The subcritical gusts are shown to have a crucial effect at low frequencies, whereas they become negligible at higher frequencies. Furthermore, alternative high-frequency formulations lead to a satisfactory accuracy above a Helmholtz number based on the duct radius of 20. The strong reduction in computational time associated with these formulations could justify their use for parametric studies in industrial context. The effect of the turbulence model is also investigated showing the relevance of Liepmann's isotropic model in the SDT case, and a possible strong effect of anisotropy in static tests. Finally, the model is compared with NASA's experimental results for two outlet guide vanes at approach condition, showing a very good agreement upstream, whereas an underestimate of 3–5
dB is observed downstream in the middle frequency range.
► An analytical model for the fan broadband noise is detailed. ► Both ingested turbulence interacting with a rotor and rotor–stator interaction are studied. ► An acoustic analogy in an annular duct is coupled with a strip theory. ► The unsteady blade loading are computing with a three-dimensional rectilinear-cascade model. ► A good agreement with the NASA SDT case is obtained and a detailed parametric study is done.
Coevolution of Genome Architecture and Social Behavior Rubenstein, Dustin R.; Ågren, J. Arvid; Carbone, Lucia ...
Trends in ecology & evolution (Amsterdam),
September 2019, 2019-09-00, Letnik:
34, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Although social behavior can have a strong genetic component, it can also result in selection on genome structure and function, thereby influencing the evolution of the genome itself. Here we explore ...the bidirectional links between social behavior and genome architecture by considering variation in social and/or mating behavior among populations (social polymorphisms) and across closely related species. We propose that social behavior can influence genome architecture via associated demographic changes due to social living. We establish guidelines to exploit emerging whole-genome sequences using analytical approaches that examine genome structure and function at different levels (regulatory vs structural variation) from the perspective of both molecular biology and population genetics in an ecological context.
Social behavior has a genetic basis but can also affect genome structure and function.As a consequence, social behavior can influence the evolution of the genome itself.We discuss bidirectional links between social behavior and genome architecture.We argue that social living can influence genome architecture via demographic processes.We propose guidelines for examining genome structure and function at different levels.
This paper extends an existing analytical model of the aeroacoustic response of a rectilinear cascade of flat-plate blades to three-dimensional incident vortical gusts, by providing closed-form ...expressions for the acoustic field inside the inter-blade channels, as well as for the pressure jump over the blades in subsonic flows. The extended formulation is dedicated to future implementation in a fan-broadband-noise-prediction tool. The intended applications include the modern turbofan engines, for which analytical modelling is believed to be a good alternative to more expensive numerical techniques. The initial model taken as a reference is based on the Wiener–Hopf technique. An analytical solution valid over the whole space is first derived by making an extensive use of the residue theorem. The accuracy of the model is shown by comparing with numerical predictions of benchmark configurations available in the literature. This full exact solution could be used as a reference for future assessment of numerical solvers, of linearized Euler equations for instance, in rectilinear or narrow-annulus configurations. In addition, the pressure jump is a key piece of information because it can be used as a source term in an acoustic analogy when the rectilinear-cascade model is applied to three-dimensional blade rows by resorting to a strip-theory approach. When used as such in a true rectilinear-cascade configuration, it reproduces the exact radiated field that can be derived directly. The solution is also compared to a classical single-airfoil formulation to highlight the cascade effect. This effect is found important when the blades of the cascade overlap significantly, but the cascade solution tends to the single-airfoil one as the overlap goes to zero. This suggests that both models can be used as the continuation of each other if needed.
Ants dominate many terrestrial ecosystems, yet we know little about their nutritional physiology and ecology. While traditionally viewed as predators and scavengers, recent isotopic studies revealed ...that many dominant ant species are functional herbivores. As with other insects with nitrogen-poor diets, it is hypothesized that these ants rely on symbiotic bacteria for nutritional supplementation. In this study, we used cloning and 16S sequencing to further characterize the bacterial flora of several herbivorous ants, while also examining the beta diversity of bacterial communities within and between ant species from different trophic levels. Through estimating phylogenetic overlap between these communities, we tested the hypothesis that ecologically or phylogenetically similar groups of ants harbor similar microbial flora. Our findings reveal: (i) clear differences in bacterial communities harbored by predatory and herbivorous ants; (ii) notable similarities among communities from distantly related herbivorous ants and (iii) similar communities shared by different predatory army ant species. Focusing on one herbivorous ant tribe, the Cephalotini, we detected five major bacterial taxa that likely represent the core microbiota. Metabolic functions of bacterial relatives suggest that these microbes may play roles in fixing, recycling, or upgrading nitrogen. Overall, our findings reveal that similar microbial communities are harbored by ants from similar trophic niches and, to a greater extent, by related ants from the same colonies, species, genera, and tribes. These trends hint at coevolved histories between ants and microbes, suggesting new possibilities for roles of bacteria in the evolution of both herbivores and carnivores from the ant family Formicidae.
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