Quantum computational finance for martingale asset pricing in incomplete markets.

A derivative is a financial asset whose future payoff is a function of underlying assets. Pricing a financial derivative involves setting up a market model, finding a martingale ("fair game") probability measure for the model from the existing asset prices, and using that probability measure to price the derivative. When the number of underlying assets and/or the number of market outcomes in the model is large, pricing can be computationally demanding. In this work, we first formulate the pricing problem in a linear algebra setting, including the realistic setting of incomplete markets where derivatives do not have a unique price. We show that the problem can be solved with a variety of quantum techniques such as quantum linear programming and the quantum linear systems algorithm. While in previous works the martingale measure is assumed to be given, here it is extracted from market variables akin to bootstrapping, a common practice among financial institutions. We discuss the quantum zero-sum game algorithm and the quantum simplex algorithm as viable subroutines. For quantum linear systems solvers, we formalize a new market assumption milder than market completeness, which allows the potential for large speedups. Towards prototype use cases, we conduct numerical experiments motivated by the Black-Scholes-Merton model.

A cross-sectional study evaluating hospitalization rates for chronic limb-threatening ischemia during the COVID-19 outbreak in Campania, Italy.

The expansion of coronavirus disease 2019 (COVID-19) prompted measures of disease containment by the Italian government with a national lockdown on March 9, 2020. The purpose of this study is to evaluate the rate of hospitalization and mode of in-hospital treatment of patients with chronic limb-threatening ischemia (CLTI) before and during lockdown in the Campania region of Italy. The study population includes all patients with CLTI hospitalized in Campania over a 10-week period: 5 weeks before and 5 weeks during lockdown (n = 453). Patients were treated medically and/or underwent urgent revascularization and/or major amputation of the lower extremities. Mean age was 69.2 ± 10.6 years and 27.6% of the patients were women. During hospitalization, 21.9% of patients were treated medically, 78.1% underwent revascularization, and 17.4% required amputations. In the weeks during the lockdown, a reduced rate of hospitalization for CLTI was observed compared with the weeks before lockdown (25 vs 74/100,000 inhabitants/year; incidence rate ratio: 0.34, 95% CI 0.32-0.37). This effect persisted to the end of the study period. An increased amputation rate in the weeks during lockdown was observed (29.3% vs 13.4%; p < 0.001). This study reports a reduced rate of CLTI-related hospitalization and an increased in-hospital amputation rate during lockdown in Campania. Ensuring appropriate treatment for patients with CLTI should be prioritized, even during disease containment measures due to the COVID-19 pandemic or other similar conditions.

The management of Takayasu's arteritis: personal experience.

Takayasu's arteritis is a chronic vasculitis mainly involving the aorta and its main branches. Almost all patients have ischemic disorders of the involved vessels. Treatment is nowadays controversial. Relapses are frequent. In the present study, we elucidate the long-term outcomes of our patients with Takayasu's arteritis. Between November 1993 and October 2003, 10 patients with Takayasu's disease were treated. All patients underwent medical treatment (corticosteroid for 7 months, cyclophosphamide for 3 months, and methotrexate for 12 months). Two patients stopped treatment with methotrexate when renal failure occurred. Four patients underwent a surgical procedure. During treatment, erythrocyte sedimentation rate and C-reactive protein concentrations were determined as indexes of inflammatory activity and treatment responsiveness. Four out of eight patients (50%) who underwent the full treatment with methotrexate had no relapse of the disease. The other four patients (50%) had relapse of the disease but had a better response to new corticosteroid treatment. The two patients who stopped methotrexate treatment died from complications of Takayasu's arteritis. In our personal experience, long-term treatment with methotrexate demonstrated a certain efficacy in avoiding relapse, maintaining stability of results, and amplifying the effects of steroid in patients with relapse.

[Alternative surgical approaches to bilio-digestive diversions in iatrogenic lesions of the bile ducts]. / Opzioni chirurgiche alternative alle derivazioni bilio digestive nelle lesioni iatrogene delle vie biliari.

The aim of this report was to evaluate the indications and limitations of non-anastomotic surgical repair in patients with bile duct injuries. These surgical approaches include both major and minor surgical procedures. The authors describe each procedure and conclude that: (i) specific diagnostic procedures are necessary to identify the exact level and severity of the injury; (ii) repair of bile duct injuries requires different approaches, which is only possible in specialized departments; and (iii) non-anastomotic surgical repair of bile duct injuries should be limited to cases detected during operation or in the immediate postoperative period.