The Hawkes process is a popular candidate for researchers to model phenomena that exhibit a self-exciting nature. The classical Hawkes process assumes the excitation kernel takes an exponential form, thus suggesting that the peak excitation effect of an event is immediate and the excitation effect decays towards 0 exponentially. While the assumption of an exponential kernel makes it convenient for studying the asymptotic properties of the Hawkes process, it can be restrictive and unrealistic for modelling purposes. A variation on the classical Hawkes process is proposed where the exponential assumption on the kernel is replaced by integrability and smoothness type conditions. However, it is substantially more difficult to conduct asymptotic analysis under this setup since the intensity process is non-Markovian when the excitation kernel is non-exponential, rendering techniques for studying the asymptotics of Markov processes inappropriate. By considering the Hawkes process with a general excitation kernel as a stationary Poisson cluster process, the intensity process is shown to be ergodic. Furthermore, a parametric setup is considered, under which, by utilising the recently established ergodic property of the intensity process, consistency of the maximum likelihood estimator is demonstrated.

Görtler vortices induced by concave curvature in supersonic turbulent flows are investigated using resolvent analysis and large-eddy simulations at Mach 2.95 and Reynolds number $ Re_{\delta }=63\,500$ based on the boundary-layer thickness $ \delta$. Resolvent analysis reveals that the most amplified coherent structures manifest as streamwise counter-rotating vortices with optimal spanwise wavelength $ 2.4\delta$ at cut-off frequency $f\delta /{u}_{\infty } =0.036$, where $ {u}_{\infty }$ is the freestream velocity. The leading spectral proper orthogonal decomposition modes with spanwise wavelength approximately $ 2\delta$ align well with the predicted coherent structures from resolvent analysis at $f\delta /{u}_{\infty } =0.036$. These predicted and extracted coherent structures are identified as Görtler vortices, driven by the Görtler instability. The preferential spanwise scale of the Görtler vortices is further examined under varying geometric and freestream parameters. The optimal spanwise wavelength is insensitive to the total turning angle beyond a critical value, but sensitive to the concave curvature $ K$ at the same turning angle. A limit spanwise wavelength $ 1.96\delta$, corresponding to an infinite concave curvature as $ K\rightarrow \infty$, is identified and validated. Increasing the freestream Mach number or decreasing the ratio of wall temperature to freestream temperature reduces the optimal wavelength normalised by $ \delta$, while variations in freestream Reynolds number have negligible impact. Additionally, a modified definition of the turbulent Görtler number $ G_{T}$ based on the peak eddy viscosity in boundary layers is proposed and employed to assess the occurrence of Görtler instability.

The varieties of capitalism thesis suggest high-income democracies cluster into distinct types, with complementarities between political, economic, and social institutions shaping long-run cross-national differences. Although featuring strongly in the comparative political economy and social policy literatures, criminal justice has received relatively little attention in this debate, but some have suggested penal policy variations map against varieties of capitalism ideal types. Using fuzzy-set qualitative comparative analysis – and data for 22 Organisation for Economic Co-operation and Development (OECD) countries over a 25-year period – we explore connections between cross-national differences in penal punitiveness and key institutional features identified in these debates. We find that the degree of punitiveness strongly overlaps with varieties of capitalism ideal types, arguing criminal justice regimes constitute a dimension of institutional complementarity in varieties of capitalism.

Using the dual-pathway framework (Beach et al., 2022a), we tested a Neuro-immune Network (NIN) hypothesis: i.e., that chronically elevated inflammatory processes may have delayed (i.e., incubation) effects on young adult substance use, leading to negative health outcomes. In a sample of 449 participants in the Family and Community Health Study who were followed from age 10 to age 29, we examined a non-self-report index of young adult elevated alcohol consumption (EAC). By controlling self-reported substance use at the transition to adulthood, we were able to isolate a significant delayed (incubation) effect from childhood exposure to danger to EAC (β = −.157, p = .006), which contributed to significantly worse aging outomes. Indirect effects from danger to aging outcomes via EAC were: GrimAge (IE = .010, [.002, .024]), Cardiac Risk (IE = −.004, [−.011, −.001]), DunedinPACE (IE = .002, [.000, .008]). In exploratory analyses we examined potential sex differences in effects, showing slightly stronger incubation effects for men and slightly stronger effects of EAC on aging outcomes for women. Results support the NIN hypothesis that incubation of immune pathway effects contributes to elevated alcohol consumption in young adulthood, resulting in accelerated aging and elevated cardiac risk outcomes via health behavior.

I apply truthmaker semantics to the logic of conditional imperatives.

Previous literature suggests that the gig economy and platform work pose challenges to social policy, including the welfare entitlement issues caused by workers’ ambiguous occupational status. Focusing on the government’s regulatory role, this study investigates platform workers’ occupational welfare (OW) by conducting in-depth interviews with forty-six food delivery workers in Hong Kong. The evidence reveals workers’ occupational risks resulting from platforms’ algorithmic devices and the misclassification of independent contractors. The denied access to private occupational pensions was considered acceptable by workers because of the perceived irrelevance of OW. While interviewees emphasised time-based flexibility as a key intangible benefit, the shifting business costs to self-employed workers was highlighted as a disadvantage. A policy dilemma appears between strengthening state regulation/protection and maintaining workers’ temporal autonomy. Arguably, the platformisation of work is translated into the gigification of OW, disentitling platform workers’ employer-provided welfare and labour protection. Platforms possess monopolising power over workers, the state displays weak regulatory power to monitor platforms, and workers’ occupational citizenship is undermined by the government’s minimal intervention. This study contributes to the literature by linking OW to platform work and revealing how the gig economy reshapes social policy, empirically offering a worker-centred analysis of OW in Hong Kong.

Young people experience different treatment compared to older adults in the English welfare and homelessness systems, encountering varying levels of protection and disadvantage. This paper uses a value-pluralist perspective to explore the normative rationales for and the ethical defensibility of these policy differences. Evidence from 38 key informant interviews suggests that the English homelessness system is shifting towards a vulnerability-oriented response to young people. But an inconsistent value framework within the welfare system systematically disadvantages them without offering a corresponding degree of protection. As such, these closely-connected areas of social policy pull in opposing directions. Although individual positions targeting young people may (to greater and lesser extents) be justifiable, this disparity in values creates an incoherent and indefensible welfare policy landscape for this group.

Negative symptoms are an important symptom dimension in schizophrenia that are often least responsive to antipsychotic medications. We revisit the current practice of identifying ‘primary’ negative symptoms and suggest that its concept would benefit from a further elaboration of their timing of emergence in relation to the dynamic neurobiological changes to enhance their utility in clinical decision-making and research.

Background: According to the World Health Organization (WHO), as of April 9, 2022, there had been 494,587,638 confirmed COVID-19 cases and 6,170,283 deaths reported worldwide. In Hong Kong, in recent outbreak, ~55% of confirmed cases were residential care home (RCH) residents and >800 staff were infected. In 2016, ~15% of people aged ≥80 years were living in residential care homes. Objectives: To assess healthcare worker (HCW) knowledge level and attitudes about PPE use in residential care homes. Methods: This cross-sectional study, included participants who worked in the residential care homes, registered as healthcare workers (HCWs). HCWs who were part-time staff or worked <3 months in the residential care home were excluded. Ethical review approval from the faculty research committee of the university was obtained in January 2022. The Knowledge, Attitude, Practical (KAP) questionnaire was adapted. The questionnaire has 33 items pertaining to knowledge, attitude, and practice regarding PPE. Results: In total, 50 questionnaires were received; 32 respondents (64%) were female and 18 (36%) were male. Nearly half of the participants had completed a high diploma course, and 32% had graduated from secondary school. Using ANOVA, there were no significant differences of education level of participants or participant knowledge level of PPE [F(2,47) = .181; P = .835], attitudes [F(2,47) = 1.995; P = .147] and practice [F(2,47) = .459; P = .635]. The Pearson correlation was used to measure the relationship between knowledge level and PPE practices. Our results indicated a significant difference and moderate correlation between knowledge level and PPE practice among HCWs. Conclusions: Knowledge level does not directly affect HCW practice regarding PPE. PPE practice skills have been influenced by various factors during the pandemic situation, such as availability of PPE, manpower, workload, and communication.