技术创新、金融市场泡沫与金融制度的适应性效率

金融市场对于技术创新的重要性是不言而喻的。但金融市场的发展不可避免地会产生泡沫。严重的泡沫会导致金融市场的崩溃,从而对经济增长造成灾难性的后果。政府对金融市场泡沫的不同干预方式又会将金融市场锁定在不同的发展路径。我们发现,政府的角色十分关键,金融市场的发展,一方面需要政府的良好执法来建立竞争性市场秩序,并降低既得利益集团对金融市场创新的阻挠;另一方面,又需要避免政府过多的行政干预所导致的对投资者权力的破坏。只有这样,才能有效地将泡沫效应转化为推动金融市场创新的原动力。     

Cost-effectiveness of subdermal implantable buprenorphine versus sublingual buprenorphine to treat opioid use disorder

Aims: Subdermal implantable buprenorphine (BSI) was recently approved to treat opioid use disorder (OUD) in clinically-stable adults. In the pivotal clinical trial, BSI was associated with a higher proportion of completely-abstinent patients (85.7% vs 71.9%; p?=?.03) vs sublingual buprenorphine (SL-BPN). Elsewhere, relapse to illicit drug use is associated with diminished treatment outcomes and increased costs. This study evaluated the cost-effectiveness of BSI vs SL-BPN from a US societal perspective.

Methods: A Markov model simulated BSI and SL-BPN cohorts (clinically-stable adults) transiting through four mutually-exclusive health states for 12 months. Cohorts accumulated direct medical costs from drug acquisition/administration; treatment-diversion/abuse; newly-acquired hepatitis-C; emergency room, hospital, and rehabilitation services; and pediatric poisonings. Non-medical costs of criminality, lost wages/work-productivity, and out-of-pocket expenses were also included. Transition probabilities to a relapsed state were derived from the aforementioned trial. Other transition probabilities, costs, and health-state utilities were derived from observational studies and adjusted for trial characteristics. Outcomes included incremental cost per quality-adjusted-life-year (QALY) gained and incremental net-monetary-benefit (INMB). Uncertainty was assessed by univariate and probabilistic sensitivity analysis (PSA).

Results: BSI was associated with lower total costs (?$4,386), more QALYs (+0.031), and favorable INMB at all willingness-to-pay (WTP) thresholds considered. Higher drug acquisition costs for BSI (+$6,492) were outpaced, primarily by reductions in emergency room/hospital utilization (?$8,040) and criminality (?$1,212). BSI was cost-effective in 89% of PSA model replicates, and had a significantly higher NMB at $50,000/QALY ($20,783 vs $15,007; p?Conclusions: BSI was preferred over SL-BPN from a health-economic perspective for treatment of OUD in clinically-stable adults. These findings should be interpreted carefully, due to some relationships having been modeled from inputs derived from multiple sources, and would benefit from comparison with outcomes from studies that employ administrative claims data or a naturalistic comparative design.     

Regime-switching and interest rates in the European monetary system

This paper examines the impact that a currency target zone has on short-term interest rates. For a number of countries in the European Monetary System, we characterize the short rate using a regime-switching model that allows for a differently parameterized mean-reverting square-root process in each regime. We find that the volatility, the level, and the speed-of-adjustment are all higher in the regime that is operative during speculative attacks and currency crises. Moreover, we allow the conditional probability of being in each regime to be state-dependent so the model can be used to examine questions relating to the likelihood of realignments and the stability of the target zone system.     

Integrating expected coverage and local reliability for emergency medical services location problems

Daskin's MEXCLP model [Daskin M. A maximum expected covering location model: formulation, properties, and heuristic solution. Transportation Science 1983;17:48-70] was one of the first efforts to capture the stochastic nature of emergency medical services (EMS) location problems within a mixed-integer formulation. With their subsequent introduction of MALP, ReVelle and Hogan [The maximum availability location problem. Transportation Science 1989;23:192-200] offered two key advances, local vehicle busyness estimates and the α-reliability objective. While these constructs have influenced many subsequent EMS location models, they have been subjected to relatively little empirical analysis. To address this, we introduce the LR-MEXCLP, a hybrid model combining the local busyness estimates of MALP with the maximum coverage objective of MEXCLP. We then solve a series of problems with all three models and employ simulation to estimate aggregate service levels. We find that LR-MEXCLP leads to modest but consistent service gains over both MALP and MEXCLP. These results support the merits of local busyness estimates, but they also suggest that the α-reliability objective may be inappropriate when seeking to maximize aggregate system response capabilities. More generally, our research underscores the utility of (a) linking modeling assumptions and goals with real-world application contexts, and (b) employing simulation or other techniques to validate theoretical results.     

论数学建模思想在高等数学教学中的渗透

高等数学是工科学生的必修课，数学建模是提高学生综合素质，锻炼分析问题能力和动手能力的一种高级形式。在高等数学教学中融入数学建模思想是搞好高等数学教学，充分发挥数学重要作用的有效手段和途径。     

Daily income target effects: Evidence from a large sample of professional commodities traders

We provide evidence of rational reference-dependent preferences in the proprietary trading of professional traders. We find increased trading effort and risk taking by traders following morning losses. Further analysis provides no evidence of a deterioration in trading performance subsequent to losses, as neither risk-adjusted performance nor trade execution appear to be negatively affected by prior losses. The evidence supports the existence of rational reference-dependent preferences in the form of trader daily income targets: these professional traders exhibit increased work effort subsequent to abnormal morning losses. The evidence is inconsistent with the alternative explanation of costly loss aversion.     

Spatial Economic Analysis in Data‐Rich Environments

Controlling for spatial effects in micro‐level studies of consumer and producer behaviour necessitates a range of analytical modifications. These range from modest changes in data collection and the definition of variables to dramatic changes in the modelling of consumer and producer decision‐making. This paper discusses conceptual, empirical and data issues involved in modelling the spatial aspects of economic behaviour in data‐rich environments. Attention is given to established and emerging agricultural economic applications of spatial data and spatial econometric methods at the micro‐scale. Recent applications of individual and household data are featured, including models of land‐use change at the urban–rural interface, agricultural land values, and technological change and technology adoption.     

The impact of the Internet on human activity–travel patterns: analysis of gender differences using multi-group structural equation models

The widespread use of the Internet for conducting various types of activities may be leading to considerable change in people’s activity–travel patterns. Past studies, however, have left many issues unaddressed. Using an Internet-activity diary dataset and multi-group structural equation modeling, this study examines the complex interactions between different types of Internet and physical activities, with a special focus on gender differences and Internet maintenance and leisure activities. The results indicate that the impacts of Internet activities on people’s activity–travel patterns are significantly different across gender. In general, Internet use for maintenance purposes has a greater impact on women’s activity–travel in the physical world, while Internet use for leisure purposes affects men’s physical activities and travel to a greater extent. Further, breaking Internet activities down into different categories reveals some hidden patterns that would not have been detected if these different types of Internet activities were lumped together as a single category.     

Limit theorems for multivariate discrete distributions

According to the usual law of small numbers a multivariate Poisson distribution is derived by defining an appropriate model for multivariate Binomial distributions and examining their behaviour for large numbers of trials and small probabilities of marginal and simultaneous successes. The weak limit law is a generalization of Poisson's distribution to larger finite dimensions with arbitrary dependence structure. Compounding this multivariate Poisson distribution by a Gamma distribution results in a multivariate Pascal distribution which is again asymptotically multivariate Poisson. These Pascal distributions contain a class of multivariate geometric distributions. Finally the bivariate Binomial distribution is shown to be the limit law of appropriate bivariate hypergeometric distributions. Proving the limit theorems mentioned here as well as understanding the corresponding limit distributions becomes feasible by using probability generating functions.     

Sustainable development. With or without mankind?

The author challenges the conventional wisdom that the main risk to Western development is environmental degradation caused by mankind. Concern over the greenhouse effect and global warming have more to do with millenium fever than reality. There is still very little evidence to suggest that these environmental phenomena result from human activity. What we do know is that there have been major cyclical fluctuations throughout history. The author cautions against implementing ‘scientistic’ policies in the face of such doubts, just because it is trendy to do so.