Multilingual language control is commonly investigated using picture-naming paradigms with explicit instructions when to switch between languages. In daily life, language switching also occurs without external cues. Cued language-switching tasks usually show a switch cost (i.e., slower responses on switch than non-switch trials). Findings of switch costs in response times are mixed for voluntary language switching. This pre-registered study uses a bilingual picture-naming paradigm to compare voluntary and cued language switching in 25 highly proficient Dutch-English bilinguals using EEG. We analysed the N2 ERP component and midfrontal theta oscillations, two common electrophysiological markers of cognitive control in task and language switching. We observed significantly smaller behavioural switch costs in the voluntary task. This suggests that voluntary language switching is less effortful than switching based on external cues. However, we found no electrophysiological switch effects in either task. We discuss factors which may contribute to the inconsistency between behavioural and electrophysiological findings.

This paper examines the issue of derivative pricing within the framework of a fractional stochastic volatility model. We present a deterministic partial differential equation system to derive an approximate expression for the derivative price. The proposed approach allows for the stochastic volatility to be expressed as a composition of deterministic functions of time and a fractional Ornstein–Uhlenbeck process. We apply this method to the European option pricing under the fractional Stein–Stein volatility model, demonstrating its feasibility and reliability through numerical simulations. Our numerical simulations also illustrate the impact of the parameters in the fractional stochastic volatility model on the option price.

Competition among the two-plasmon decay (TPD) of backscattered light of stimulated Raman scattering (SRS), filamentation of the electron-plasma wave (EPW) and forward side SRS is investigated by two-dimensional particle-in-cell simulations. Our previous work [K. Q. Pan et al., Nucl. Fusion 58, 096035 (2018)] showed that in a plasma with the density near 1/10 of the critical density, the backscattered light would excite the TPD, which results in suppression of the backward SRS. However, this work further shows that when the laser intensity is so high ($>{10}^{16}$ W/cm2) that the backward SRS cannot be totally suppressed, filamentation of the EPW and forward side SRS will be excited. Then the TPD of the backscattered light only occurs in the early stage and is suppressed in the latter stage. Electron distribution functions further show that trapped-particle-modulation instability should be responsible for filamentation of the EPW. This research can promote the understanding of hot-electron generation and SRS saturation in inertial confinement fusion experiments.

Currently there is lack of knowledge on how new types of alternative fuels and their storage conditions change the droplet evaporation characteristics. Liquid fuel is commonly stored in wide varieties of containers, where fuel characteristics may change because of the exposure to the material of the container. This study evaluates the impact of different storage containers on droplet evaporation characteristics of different fuels. It was found that there is a distinct phase transition between high volatility to low volatility phase in each fuel stored in steel drums verses fuel that is stored in plastic drums. The type of fuel contaminated by polymer additive has a high impact on fuel droplet burn rates. Polymer additives also have an impact on nucleate boiling, sub-droplets and soot particles. The burning rate constant, K, of selected pure aromatics, various fuel mixtures and Jet A with different cetane numbers have been evaluated. Research has shown that in the low volatility combustion phase a trend reduction of lowest boiling point pure aromatic burning rate to the highest boiling point pure aromatic burning rate is obvious. Irregular change in droplet diameter between the high volatility phase and low volatility phase during the combustion of aromatics blend was observed. This work has also evaluated the relationship between burning rates and cetane numbers.

To meet the increasing communication demands, the satellites need to be equipped with the high-accuracy and large-aperture antennas. One of the effective methods to construct the modular antennas with ultra-high accuracy and ultra-large aperture is on-orbit assembly technology. During the on-orbit assembly missions, the assembly error is a key factor to affect the surface accuracy of the modular antennas. This paper studies the node design of each module and the assembly error analysis of the modular antennas. A design method of the module nodes is presented with consideration of the assembly gap between two modules. Meanwhile, a soft connection mechanism is designed to ensure the mobility among the assembly modules. To investigate the transmission law of the assembly errors, an analytical model of assembly error is derived based on the exponential product method. In order to establish the deformation surface with rotation and displacement assembly errors, an error ball concept is proposed by the analytical model. To decrease the assembly errors, the actuators are installed among some modules. Moreover, an adjustment method is proposed to obtain the adjustment amounts of actuators. Finally, the correctness of analytical model and the effectiveness of the adjustment method are demonstrated by the numerical simulations.

Fully rough wall-sheared turbulence is composed of an inner and outer layer, the former occupied by sinuous structures sustained by the well-known autonomous inner cycle, the latter occupied by inclined parcels of momentum deviations relative to the average. The outer-layer structures are also known as uniform momentum zones (UMZs), where the presence of successive UMZs manifests instantaneously with a distinct ‘staircase’ pattern in streamwise velocity. Direct numerical simulation (DNS) of fully rough channel turbulence was recently used to interpret UMZs as wakes originating from antecedent bluff-body-like interactions within the inner layer (Anderson & Salesky, J. Fluid Mech., vol. 906, 2020, A8). Wake-scaling arguments agreed precisely with instantaneous results from DNS. Foremost among these results was evidence that the instantaneous wall-normal gradient of streamwise velocity exhibited scaling of ${\sim }x_3^{-1/2}$, where $x_3$ is wall-normal location; this is in contrast to logarithmic scaling, which requires the wall-normal gradient of streamwise velocity to scale as ${\sim }x_3^{-1}$. Herein, wake-scaling arguments have been advanced and compared against results from wall-modelled large-eddy simulation (LES). New results from the ‘bottom up’ wake-scaling arguments agree with LES results, such that the shear associated with the instantaneous staircase-like streamwise velocity follows a clear trend. We have leveraged conditional sampling during LES – predicated upon instantaneous low-frequency, high-magnitude surface stress values known to correspond to large-scale inertial-layer coherence – to further assess the predictive value of the wake-scaling arguments. Model results compare favourably.

A uniform distribution of roughness elements of height, $h$, enhances turbulent momentum exchanges in wall flows of thickness, $\delta$. For $\delta/h$ above a nominal threshold, this distribution of elements enhances drag, but does not induce structural response to outer-/inertial-layer turbulence. Large-scale spatial variability in element attributes, however, can induce $\delta$-scale response in the instantaneous and Reynolds-averaged flow. For the case of a large-scale heterogeneity aligned orthogonal and parallel to the primary transport direction, the Reynolds-averaged flow responds with formation of an internal boundary layer (IBL) and counter-rotating secondary cells, respectively. For oblique flow-heterogeneity alignments, Anderson (J. Fluid Mech., vol. 886, 2020, p. A15), showed that IBL formation persists for flow-heterogeneity aligned at a series of oblique angles, before abruptly collapsing and transitioning to counter-rotating secondary cells at a critical obliquity. We define flow-roughness obliquity angle with symbol, $\theta$, where $\theta = 0$ and ${\rm \pi}/2$ corresponds with streamwise and spanwise heterogeneity, respectively, while the critical obliquity angle is denoted by $\theta_c$. We have used large-eddy simulation to perform a comprehensive parametric assessment on the effect of obliquity, element height, and spacing between adjacent ‘rows’ of elements, all of which is intended to identify the aforementioned critical obliquity. We once again report the aforementioned IBL persistence. It is shown that this response is a product of successive element sheltering, which can be recorded via the element frontal area index: as obliquity angle increases, there is a critical obliquity at which downflow elements fall in the sheltering zone of upflow elements; we find that $\theta_c = 22 {\rm \pi}/ 56$.

To evaluate the impacts of guanidinoacetic acid (GAA) and coated folic acid (CFA) on growth performance, nutrient digestion and hepatic gene expression, fifty-two Angus bulls were assigned to four groups in a 2 × 2 factor experimental design. The CFA of 0 or 6 mg/kg dietary DM folic acid was supplemented in diets with GAA of 0 (GAA−) or 0·6 g/kg DM (GAA+), respectively. Average daily gain (ADG), feed efficiency and hepatic creatine concentration increased with GAA or CFA addition, and the increased magnitude of these parameters was greater for addition of CFA in GAA− diets than in GAA+ diets. Blood creatine concentration increased with GAA or CFA addition, and greater increase was observed when CFA was supplemented in GAA+ diets than in GAA− diets. DM intake was unchanged, but rumen total SCFA concentration and digestibilities of DM, crude protein, neutral-detergent fibre and acid-detergent fibre increased with the addition of GAA or CFA. Acetate:propionate ratio was unaffected by GAA, but increased for CFA addition. Increase in blood concentrations of albumin, total protein and insulin-like growth factor-1 (IGF-1) was observed for GAA or CFA addition. Blood folate concentration was decreased by GAA, but increased with CFA addition. Hepatic expressions of IGF-1, phosphoinositide 3-kinase, protein kinase B, mammalian target of rapamycin and ribosomal protein S6 kinase increased with GAA or CFA addition. Results indicated that the combined supplementation of GAA and CFA could not cause ADG increase more when compared with GAA or CFA addition alone.

In conventional linear parameter-varying (LPV) modelling and gain scheduling control design for turbojet engines, the linearisation is performed at a set of equilibrium points, and the validity of such LPV models is ensured near the equilibria. However, the linear model can only provide an approximate description of the engine’s state when the system operates away from equilibrium. In this paper, it is suggested that such linearisation should be carried out not only at equilibrium states but also in transient (off-equilibrium) operating regimes. This will result in a global approximation to the system states whether equilibrium or off-equilibrium. Theoretically, the transient control performance can be improved by introducing such an off-equilibrium linearisation-based control procedure. Subsequently, a gain scheduling control procedure based on off-equilibrium linearisation models is proposed by using sum-of-squares (SOS) programming, which, compared with many convex programming methods, can provide less conservative results. The resulting off-equilibrium linearisation-based nonlinear control procedure with SOS programming can capture a wide range of transient engine dynamics with better accuracy, and further achieve better control performance.

Ovarian follicle selection is a natural biological process in the pre-ovulatory hierarchy in birds that drives growing follicles to be selected within the ovulatory cycle. Follicle selection in birds is strictly regulated, involving signaling pathways mediated by dietary nutrients, gonadotrophic hormones and paracrine factors. This study aimed to test the hypothesis that dietary Ca may participate in regulating follicle selection in laying ducks through activating the signaling pathway of cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/extracellular signal-regulated kinase (ERK), possibly mediated by gonadotrophic hormones. Female ducks at 22 weeks of age were initially fed one of two Ca-deficient diets (containing 1.8% or 0.38% Ca) or a Ca-adequate control diet (containing 3.6% Ca) for 67 days (depletion period), then all birds were fed the Ca-adequate diet for an additional 67 days (repletion period). Compared with the Ca-adequate control, ducks fed 0.38% Ca during the depletion period had significantly decreased (P < 0.05) numbers of hierarchical follicles and total ovarian weight, which were accompanied by reduced egg production. Plasma concentration of FSH was decreased by the diet containing 1.8% Ca but not by that containing 0.38%. The ovarian content of cAMP was increased with the two Ca-deficient diets, and phosphorylation of PKA and ERK1/2 was increased with 0.38% dietary Ca. Transcripts of ovarian estradiol receptor 2 and luteinizing hormone receptor (LHR) were reduced in the ducks fed the two Ca-deficient diets (P < 0.05), while those of the ovarian follicle stimulating hormone receptor (FSHR) were decreased in the ducks fed 0.38% Ca. The transcript abundance of ovary gap junction proteins, A1 and A4, was reduced with the Ca-deficient diets (P < 0.05). The down-regulation of gene expression of gap junction proteins and hormone receptors, the increased cAMP content and the suppressed hierarchical follicle numbers were reversed by repletion of dietary Ca. These results indicate that dietary Ca deficiency negatively affects follicle selection of laying ducks, independent of FSH, but probably by activating cAMP/PKA/ERK1/2 signaling pathway.

When constrained by limited resources, how do we choose axioms of rationality? The target article relies on Bayesian reasoning that encounter serious tractability problems. We propose another axiomatic foundation: quantum probability theory, which provides for less complex and more comprehensive descriptions. More generally, defining rationality in terms of axiomatic systems misses a key issue: rationality must be defined by humans facing vague information.

The strong-coupling mode, called the “quasimode”, is excited by stimulated Brillouin scattering (SBS) in high-intensity laser–plasma interactions. Also SBS of the quasimode competes with SBS of the fast mode (or slow mode) in multi-ion species plasmas, thus leading to a low-frequency burst behavior of SBS reflectivity. Competition between the quasimode and the ion-acoustic wave (IAW) is an important saturation mechanism of SBS in high-intensity laser–plasma interactions. These results give a clear explanation of the low-frequency periodic burst behavior of SBS and should be considered as a saturation mechanism of SBS in high-intensity laser–plasma interactions.