In this study, the length scaling for the boundary layer separation induced by two incident shock waves is experimentally and analytically investigated. The experiments are performed in a Mach 2.73 flow. A double-wedge shock generator with two deflection angles ($\alpha _1$ and $\alpha _2$) is employed to generate two incident shock waves. Two deflection angle combinations with an identical total deflection angle are adopted: ($\alpha _1 = 7^\circ$, $\alpha _2 = 5^\circ$) and ($\alpha _1 = 5^\circ$, $\alpha _2 = 7^\circ$). For each deflection angle combination, the flow features of the dual-incident shock wave–turbulent boundary layer interactions (dual-ISWTBLIs) under five shock wave distance conditions are examined via schlieren photography, wall-pressure measurements and surface oil-flow visualisation. The experimental results show that the separation point moves downstream with increasing shock wave distance ($d$). For the dual-ISWTBLIs exhibiting a coupling separation state, the upstream interaction length ($L_{int}$) of the separation region approximately linearly decreases with increasing $d$, and the decrease rate of $L_{int}$ with $d$ increases with the second deflection angle under the condition of an identical total deflection angle. Based on control volume analysis of mass and momentum conservations, the relation between $L_{int}$ and $d$ is analytically determined to be approximately linear for the dual-ISWTBLIs with a coupling separation region, and the slope of the linear relation obtained analytically agrees well with that obtained experimentally. Furthermore, a prediction method for $L_{int}$ of the dual-ISWTBLIs with a coupling separation region is proposed, and the relative error of the predicted $L_{int}$ in comparison with the experimental result is $\sim$10 %.

The association between time-restricted eating (TRE) and the risk of nonalcoholic fatty liver disease (NAFLD) is less studied. Moreover, whether the association is independent of physical exercise or diet quality or quantity is uncertain. In this nationwide cross-sectional study of 3,813 participants, the timing of food intakes was recorded by 24-h recalls; NAFLD was defined through vibration-controlled transient elastography in the absence of other causes of chronic liver disease. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression. Participants with daily eating window of ≤ 8 h had lower odds of NAFLD (OR = 0.70, 95% CI: 0.52-0.93), compared to those with ≥ 10 h window. Early (5am-3pm) and late TRE (11am-9pm) showed inverse associations with NAFLD prevalence without statistical heterogeneity (p heterogeneity = 0.649) with ORs of 0.73 (95% CI: 0.36-1.47) and 0.61 (95% CI: 0.44-0.84), respectively. Such inverse association seemed stronger in participants with lower energy intake (OR = 0.58, 95% CI: 0.38-0.89, p interaction = 0.020). There are no statistical differences in the TRE-NAFLD associations according to physical activity (p interaction = 0.390) or diet quality (p interaction = 0.110). TRE might be associated with lower likelihood of NAFLD. Such inverse association is independent of physical activity and diet quality, and appears stronger in individuals consuming lower energy. Given the potential misclassification of TRE based on one- or two-day recall in the analysis, epidemiological studies with validated methods for measuring the habitual timing of dietary intake are warranted.

The oscillatory Kelvin–Helmholtz (K–H) instability of a planar liquid sheet was experimentally investigated in the presence of an axial oscillating gas flow. An experimental system was initiated to study the oscillatory K–H instability. The surface wave growth rates were measured and compared with theoretical results obtained using the authors’ early linear method. Furthermore, in a larger parameter range experimentally studied, it is interesting that there are four different unstable modes: first disordered mode (FDM), second disordered mode (SDM), K–H harmonic unstable mode (KHH) and K–H subharmonic unstable mode (KHS). These unstable modes are determined by the oscillating amplitude, oscillating frequency and liquid inertia force. The frequencies of KHH are equal to the oscillating frequency; the frequency of KHS equals half the oscillating frequency, while the frequencies of FDM and SDM are irregular. By considering the mechanism of instability, the instability regime maps on the relative Weber number versus liquid Weber number (Werel–Wel) and the Weber number ratio versus the oscillating frequency (Werel/Wel–$\varOmega$s2) were plotted. Among these four modes, KHS is the most unexpected: the frequency of this mode is not equal to the oscillating frequency, but the surface wave can also couple with the oscillating gas flow. Linear instability theory was applied to divide the parameter range between the different unstable modes. According to linear instability theory, K–H and parametric unstable regions both exist. However, note that all four modes (KHH, KHS, FDM and SDM) corresponded primarily to the K–H unstable region obtained from the theoretical analysis. Nevertheless, the parametric unstable mode was also observed when the oscillating frequency and amplitude were relatively low, and the liquid inertia force was relatively high. The surface wave amplitude was small but regular, and the evolution of this wave was similar to that of Faraday waves. The wave oscillating frequency was half that of the surface wave.

Similar to research on risky choice, the traditional analysis of intertemporal choice takes the view that an individual behaves so as to maximize the discounted sum of all future utilities. The well-known Allais paradox contradicts the fundamental postulates of maximizing the expected value or utility of a risky option. We describe a violation of the law of diminishing marginal utility as well as an intertemporal version of the Allais paradox.

Everyone faces uncertainty on a daily basis. Two kinds of probability expressions, verbal and numerical, have been used to characterize the uncertainty that we face. Because our cognitive concept of living things differs from that of non-living things, and distinguishing cognitive concepts might have linguistic markers, we designed four studies to test whether people use different probability expressions when faced with animate or inanimate uncertainty. We found that verbal probability is the preferred way to express animate uncertainty, whereas numerical probability is the preferred way to express inanimate uncertainty. The “verbal-animate” and “numerical-inanimate” associations were robust enough to persist when tested with forced-choice response patterns regardless of the information (e.g., equally likely outcomes, frequencies, or personal beliefs) used to construct probabilities of events. When the response pattern was changed to free-responses, the associations were evident unless the subjects were asked to write their own probability predictions for vague uncertainty. Given that the world around us consists of both animate (i.e., living) and inanimate (i.e., non-living) things, “verbal-animate” and “numerical-inanimate” associations may play a major role in risk communication and may otherwise be useful for practitioners and consultants.

By manipulating the scale in graphs, this study demonstrated a new evaluation bias caused by attribute salience in graphical representations. That is, (de)compressing the graph axis scale changed the relative distance with respect to the options of a given attribute and thus changed the salience of the information in graphical representations. Experiment 1 showed that the differences in the graphical representations had a significant impact on the evaluation. Experiment 2 repeated the scale manipulation effect in a different scenario and extended it to a multi-options context. Experiment 3 disentangled the effect of scale distance manipulation from the other variables (e.g., scale resolution and assignment of attributes to axes) and further supported the finding of Experiment 1. These results indicated that attribute salience in graphical representations clearly affects evaluations and that graphs can be manipulated to cause very different impressions of the same data. This finding is not consistent with the axioms of normative economic theory. Experiment 3 also tested the attribute importance hypothesis, but the evidence indicated that the participants did not regard the longer axis as the more important attribute. Finally, we related our findings to the impact of visual processing on decision making and discussed them from the perspective of two-system cognitive theory.

According to the positive time-discounting assumption of intertemporal decision-making, people prefer to undergo negative events in the future rather than in the present. However, negative discounting has been identified in the intertemporal choice and loss domains, which refers to people’s preference to experience negative events earlier rather than later. Studies have validated and supported the "anticipated dread" as an explanation for negative discounting. This study again explored the effect of anticipated dread on intertemporal choice using content analysis; that is, having participants identify anticipated dread among reasons for negative discounting. This study also validated the effect of anticipated dread on negative discounting by manipulating anticipated dread. This study adds empirical and direct evidence for the role of anticipated dread in negative discounting.

In “The value of nothing: asymmetric attention to opportunity costs drives intertemporal decision making” Read, Olivola and Hardisty (2017) proposed an asymmetric subjective opportunity cost (ASOC) effect to explain and predict why impatience can be detected in intertemporal choice. This work deserves to be replicated and extended for its novel and potentially important findings. The present study aimed to examine the reliability and robustness of the evidence presented by Read et al. by conducting precise replications of their key findings in Study 1. The ASOC effect (Read, et al., 2017) was important for expanding its application and reported to be typically stronger when baseline larger-but-later option (LL) and smaller-but-sooner option (SS) preferences were closer to 50% in the authors’ original condition. Therefore, the present study also aimed to replicate and test the ASOC effect when baseline LL preferences were higher or lower than those in the original condition. We intended to set two additional conditions wherein either LL or SS is more obviously favored (i.e., baseline LL preferences were higher or lower than those in the original condition) by respectively applying the common difference effect (Kirby & Herrnstein, 1995) and the unit effect (Burson, Larrick & Lynch Jr., 2009; Pandelaere, Briers & Lembregts, 2011). Having successfully generated two more obviously favored conditions, the ASOC effect was replicated and confirmed under the original condition and one additional condition wherein SS was more obviously favored. However, the ASOC effect was not detected under the other additional condition wherein LL was more obviously favored. The implications of these findings were discussed.

Whether starchy and non-starchy vegetables have distinct impacts on health remains unknown. We prospectively investigated the intake of starchy and non-starchy vegetables in relation to mortality risk in a nationwide cohort. Diet was assessed using 24-h dietary recalls. Deaths were identified via the record linkage to the National Death Index. Hazard ratios (HR) and 95 % CI were calculated using Cox regression. During a median follow-up of 7·8 years, 4904 deaths were documented among 40 074 participants aged 18 years or older. Compared to those with no consumption, participants with daily consumption of ≥ 1 serving of non-starchy vegetables had a lower risk of mortality (HR = 0·76, 95 % CI 0·66, 0·88, P trend = 0·001). Dark-green and deep-yellow vegetables (HR = 0·79, 95 % CI 0·63, 0·99, P trend = 0·023) and other non-starchy vegetables (HR = 0·80, 95 % CI 0·70, 0·92, P trend = 0·004) showed similar results. Total starchy vegetable intake exhibited a marginally weak inverse association with mortality risk (HR = 0·89, 95 % CI 0·80, 1·00, P trend = 0·048), while potatoes showed a null association (HR = 0·93, 95 % CI 0·82, 1·06, P trend = 0·186). Restricted cubic spline analysis suggested a linear dose–response relationship between vegetable intake and death risk, with a plateau at over 300 and 200 g/d for total and non-starchy vegetables, respectively. Compared with starchy vegetables, non-starchy vegetables might be more beneficial to health, although both showed a protective association with mortality risk. The risk reduction in mortality plateaued at approximately 200 g/d for non-starchy vegetables and 300 g/d for total vegetables.

The potential of artificial intelligence (AI) has grown exponentially in recent years, which not only generates value but also creates risks. AI systems are characterised by their complexity, opacity and autonomy in operation. Now and in the foreseeable future, AI systems will be operating in a manner that is not fully autonomous. This signifies that providing appropriate incentives to the human parties involved is still of great importance in reducing AI-related harm. Therefore, liability rules should be adapted in such a way to provide the relevant parties with incentives to efficiently reduce the social costs of potential accidents. Relying on a law and economics approach, we address the theoretical question of what kind of liability rules should be applied to different parties along the value chain related to AI. In addition, we critically analyse the ongoing policy debates in the European Union, discussing the risk that European policymakers will fail to determine efficient liability rules with regard to different stakeholders.

Human immunodeficiency virus (HIV) has been widely prevalent among older men (aged ≥50 years old) in Sichuan Province. The study aimed to discover associated factors with the new HIV infection in older men, and provide a scientific basis for the prevention and control of acquired immunodeficiency syndrome (AIDS) in this group. A cross-sectional survey study of newly reported HIV/AIDS and general male residents aged 50 years and older was conducted between April and June 2019, with a resample of respondents to identify cases and controls, followed by a case–control study. Logistic regression was applied to analyse the association between the selected factors and new HIV infection among older men. At last, 242 cases and 968 controls were included. The results of multiple logistic regression suggested that many factors including living alone/concentrated (OR 1.56, 95% CI 1.20–2.04, P = 0.001), have a history of migrant worker (OR 2.10, 95% CI 1.61–2.73, P < 0.001), have commercial sexual behaviour (OR 1.71, 95% CI 1.32–2.22, P < 0.001), married (OR 0.48, 95% CI 0.37–0.64, P < 0.001), have a history of HIV antibody testing (OR 0.73, 95% CI 0.56–0.96, P = 0.026), HIV-related knowledge (OR 0.55, 95% CI 0.42–0.72, P < 0.001) were associated with new HIV infection among older men. The present study revealed some potential risky/protective factors altogether. The results highlighted the direction of HIV/AIDS prevention and control among older men, and it is a social issue that requires the joint participation of the whole society.

This study evaluated the association between inflammatory diets as measured by the Dietary Inflammatory index (DII), inflammation biomarkers and the development of preeclampsia among the Chinese population. We followed the reporting guidelines of the Strengthening the Reporting of Observational Studies in Epidemiology statement for observational studies. A total of 466 preeclampsia cases aged over 18 years were recruited between March 2016 and June 2019, and 466 healthy controls were 1:1 ratio matched by age (±3 years), week of gestation (±1 week) and gestational diabetes mellitus. The energy-adjusted DII (E-DII) was computed based on dietary intake assessed using a seventy-nine item semiquantitative FFQ. Inflammatory biomarkers were analysed by ELISA kits. The mean E-DII scores were −0·65 ± 1·58 for cases and −1·19 ± 1·47 for controls (P value < 0·001). E-DII scores positively correlated with interferon-γ (r s = 0·194, P value = 0·001) and IL-4 (r s = 0·135, P value = 0·021). After multivariable adjustment, E-DII scores were positively related to preeclampsia risk (P trend < 0·001). The highest tertile of E-DII was 2·18 times the lowest tertiles (95 % CI = 1·52, 3·13). The odds of preeclampsia increased by 30 % (95 % CI = 18 %, 43 %, P value < 0·001) for each E-DII score increase. The preeclampsia risk was positively associated with IL-2 (OR = 1·07, 95 % CI = 1·03, 1·11), IL-4 (OR = 1·26, 95 % CI = 1·03, 1·54) and transforming growth factor beta (TGF-β) (OR = 1·17, 95 % CI = 1·06, 1·29). Therefore, proinflammatory diets, corresponding to higher IL-2, IL-4 and TGF-β levels, were associated with increased preeclampsia risk.