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In this paper, we study utility maximisation with proportional transaction costs. Assuming extended weak convergence of the underlying processes, we prove the convergence of the time-0 values of the corresponding utility maximisation problems. Moreover, we establish a limit theorem for the optimal trading strategies. The proofs are based on the extended weak convergence theory developed in Aldous (Weak Convergence of Stochastic Processes for Processes Viewed in the Strasbourg Manner, 1981) and on the Meyer–Zheng topology introduced in Meyer and Zheng (Ann. Inst. Henri Poincaré Probab. Stat. 20:353–372, 1984).

In this paper we find tight sufficient conditions for the continuity of the value of the utility maximization problem from terminal wealth with respect to the convergence in distribution of the underlying processes. We also establish a weak convergence result for the terminal wealths of the optimal portfolios. Finally, we apply our results to the computation of the minimal expected shortfall (shortfall risk) in the Heston model by building an appropriate lattice approximation.

This paper focuses on martingale optimal transport problems when the martingales are assumed to have bounded quadratic variation. First, we give a result that characterizes the existence of a probability measure satisfying some convex transport constraints in addition to having given initial and terminal marginals. Several applications are provided: martingale measures with volatility uncertainty, optimal transport with capacity constraints, and Skorokhod embedding with bounded times. Next, we extend this result to multi-marginal constraints. Finally, we consider an optimal transport problem with constraints and obtain its Kantorovich duality. A corollary of this result is a monotonicity principle which gives a geometric way of identifying the optimizer.

The COVID-19 pandemic and subsequent lockdowns highlight the close and delicate relationship between a country’s public health and economic health. Models that combine macroeconomic factors with traditional epidemic dynamics to calculate the impacts of a disease outbreak are therefore extremely useful for policymakers seeking to evaluate the best course of action in such a crisis. We developed a macroeconomic SIR model that considers herd immunity, behavior-dependent transmission rates, remote workers, and the indirect externalities of lockdowns. It is formulated as an exit time control problem where a social planner is able to prescribe separate levels of the lockdown low-risk and high-risk portions of the adult population. The model predicts that by considering the possibility of reaching herd immunity, high-risk individuals are able to leave lockdown sooner than in models where herd immunity is not considered. Additionally, a behavior-dependent transmission rate (which represents increased personal caution in response to increased infection levels) can lower both output loss and total mortality. Overall, the model-determined optimal lockdown strategy, combined with individual actions to slow virus transmission, is able to reduce total mortality to one-third of the model-predicted no-lockdown level of mortality.

We study heterogeneously interacting diffusive particle systems with mean-field-type interaction characterized by an underlying graphon and their finite particle approximations. Under suitable conditions, we obtain exponential concentration estimates over a finite time horizon for both 1- and 2-Wasserstein distances between the empirical measures of the finite particle systems and the averaged law of the graphon system.

Fowl adenovirus can cause important diseases in chickens such as inclusion body hepatitis, hepatitis hydropericardium syndrome, and gizzard erosion and ulceration. Inclusion body hepatitis has been regularly reported from many countries. This is the first case report from Turkey, describing an outbreak of inclusion body hepatitis in broiler farms due to fowl adenovirus-8b (FAdV-8b). Broiler flocks with mortality about 10% were visited in Turkey, and necropsy was performed on dead birds. Samples were subjected to PCR assay to detect FAdV and other viral pathogens. After sequencing, phylogenetic analysis was performed and the nucleotide sequences of hexon genes were compared with the FAdV sequences data available in GenBank. Clinical signs such as anorexia, depression, ruffled feathers, huddling, and greenish diarrhoea were observed. Mortality started at the 8 day of age and ranged from 10% to 14%. Necropsy showed severe hepatitis, jaundice, and pancreatitis. The main necropsy findings included a pale, enlarged, haemorrhagic, and friable liver along with swollen and haemorrhagic kidneys and spleen. PCR and sequence analysis revealed the presence of fowl adenovirus serotype 8b (FAdV-E). This is the first report on characterisation and the pathological lesions associated with FAdV in broilers in Turkey. Our findings suggest that FAdV strains could be an emerging pathogen in Turkish broilers and could actively contribute to hepatitis and immunosuppression.

Background Fowl adenovirus-4 is a causative agent of hydropericardium hepatitis syndrome (HHS) in chickens and has been frequently reported from many countries. Fowl adenoviruses cause severe disease and mortality in broiler and layer breeders in Azerbaijan. Therefore, in this study, pathological lesions and the dissemination of fowl adenovirus-4 into the visceral organs of infected birds were investigated as well as molecular characterisation of detected strains. For this, liver, heart and spleen from 20 necropsied chickens originated from a broiler breeder flock and a layer breeder flock were embeded on the FTA cards and the samples were analysed for adenovirus-DNA by PCR and sequencing. Results The findings of necropsy in both broiler and layer breeder chickens were similar, and the liver was severely effected showing hepatitis, and the heart with hydropericardium lesions. The kidneys were swollen with haemorrhages and small white foci on the surface of the spleens were noted. Intestinal congestion and ecchymotic hemorrhages were also observed in some birds. Fowl adenovirus-4-DNA was detected by PCR in all collected organs of 20 birds. The sequence analysis revealed that fowl adenovirus-4 present in Azerbaijan and close similarity of the hexon genes of the adenoviruses existing in the Middle East, North America, far east and Indian subcontinent were determined by phylogenetic analysis. However, sequence diversity was detected from the adenovirus strains circulating in Europe, North and South America. Conclusions This study indicates the impact of fowl adenovirus-4 on the poultry health and production, and improved disease control and prevention strategies are necessary to reduce the HHS disease in chickens in Azerbaijan.

In this paper, we show existence and uniqueness of solutions of the infinite horizon McKean–Vlasov FBSDEs using two different methods, which lead to two different sets of assumptions. We use these results to solve the infinite horizon mean field type control problems and mean field games.

We solve the optimal control problem of a one-dimensional reflected stochastic differential equation, whose coefficients can be path dependent. The value function of this problem is characterized by a backward stochastic partial differential equation (BSPDE) with Neumann boundary conditions. We prove the existence and uniqueness of a sufficiently regular solution for this BSPDE, which is then used to construct the optimal feedback control. In fact, we prove a more general result: the existence and uniqueness of strong solution for the Neumann problem for general nonlinear BSPDEs, which might be of interest even out of the current context.