Lag Length Selection for Unit Root Tests in the Presence of Nonstationary Volatility

A number of recent papers have focused on the problem of testing for a unit root in the case where the driving shocks may be unconditionally heteroskedastic. These papers have, however, taken the lag length in the unit root test regression to be a deterministic function of the sample size, rather than data-determined, the latter being standard empirical practice. We investigate the finite sample impact of unconditional heteroskedasticity on conventional data-dependent lag selection methods in augmented Dickey–Fuller type regressions and propose new lag selection criteria which allow for unconditional heteroskedasticity. Standard lag selection methods are shown to have a tendency to over-fit the lag order under heteroskedasticity, resulting in significant power losses in the (wild bootstrap implementation of the) augmented Dickey–Fuller tests under the alternative. The proposed new lag selection criteria are shown to avoid this problem yet deliver unit root tests with almost identical finite sample properties as the corresponding tests based on conventional lag selection when the shocks are homoskedastic.     

Bayesian adaptive dose‐escalation designs for simultaneously estimating the optimal and maximum safe dose based on safety and efficacy

The main purpose of dose‐escalation trials is to identify the dose(s) that is/are safe and efficacious for further investigations in later studies. In this paper, we introduce dose‐escalation designs that incorporate both the dose‐limiting events and dose‐limiting toxicities (DLTs) and indicative responses of efficacy into the procedure. A flexible nonparametric model is used for modelling the continuous efficacy responses while a logistic model is used for the binary DLTs. Escalation decisions are based on the combination of the probabilities of DLTs and expected efficacy through a gain function. On the basis of this setup, we then introduce 2 types of Bayesian adaptive dose‐escalation strategies. The first type of procedures, called “single objective,” aims to identify and recommend a single dose, either the maximum tolerated dose, the highest dose that is considered as safe, or the optimal dose, a safe dose that gives optimum benefit risk. The second type, called “dual objective,” aims to jointly estimate both the maximum tolerated dose and the optimal dose accurately. The recommended doses obtained under these dose‐escalation procedures provide information about the safety and efficacy profile of the novel drug to facilitate later studies. We evaluate different strategies via simulations based on an example constructed from a real trial on patients with type 2 diabetes, and the use of stopping rules is assessed. We find that the nonparametric model estimates the efficacy responses well for different underlying true shapes. The dual‐objective designs give better results in terms of identifying the 2 real target doses compared to the single‐objective designs.     

A theoretical analysis of the value added intellectual coefficient (VAIC)

Journal of Management and Governance - This paper offers a critical assessment of the value added intellectual coefficient (VAIC) through the analysis of the coherence of the definitions of and...     

Techno-sovereignism: the political rationality of contemporary Italian populism

This article provides an original exploration of the self-identified populist coalition leading the Italian government between 2018 and 2019. The analysis, informed by a governmentality approach, starts by scrutinising the economic, social, and cultural issues framed as political “problems” by the coalition, also highlighting the tensions underlying such constructions. The second step charts how this political subject sought to address those problems by deploying an array of political technologies. From examining these two dimensions, the article then can discern the composite rationality—techno-sovereignism—that drove precariously the coalition’s art of government. Finally, the article sketches out some forms of contestation against the techno-sovereignist operations, whose significance may stretch beyond the Italian borders. Overall, although the Italian populist coalition turned out to be ephemeral, the dynamics that characterized its emergence and functioning could still be used heuristically to understand the interactions and reciprocal adjustments possibly used by right-wing and technocratic populist groups to exert political power conjointly.

     

Research into work stress in Italy: A review

This paper reviews the development of stress research in Italy from the late 1960s onwards. It focuses on 1975 as the year when the first real studies on work stress were published, and interest was kindled in the psychological factors which affect physical health and in the physiological correlates of work stress. Much important work in these aspects of occupational health was started at this time at the Clinic of Work in Milan and at the University of Perugia. By the 1980s, Italian psychologists were also showing considerable interest in work stress, and the more psychological literature had begun to exceed that of a medical and physiological orientation. Despite this progress, stress research in Italy is still in its infancy, and the recognition of stress as an issue for management and trade unions is weak.     

Devaluation expectations and the unit root hypothesis: The Italian Lira in the European monetary system

Summary In several studies the unit root hypothesis of EMS exchange rates is analysed within the context of devaluation expectations estimation. By means of bootstrap inference it is shown that these procedures are not compatible with standard Dickey-Fuller significance levels and may lead to a wrong rejection of the null hypothesis. In the case of the Italian Lira/Deutsche Mark exchange rate, the hypothesis of a unit root is not rejected and expectations can be modelled by means of a reflected Brownian motion. The estimated devaluation expectations are related with some macro variables which provide evidence for the structure of expectations. This research has been partially supported with 40% and 60% MURST grants. The author wishes to thank the Bank of Italy for the exchange rates and the interest rates data and Ulf S?derstr?m for providing macroeconomic indicators. Useful suggestions from Riccardo Cesari, Michele Costa and two anonymous referees are gratefully acknowledged.     

Exploring theoretical frameworks for the analysis of fertility fluctuations

Analysis of scientific debate on the determinants of procreational choice leads the author to identify four main decisional logics: primary adaptation, economic rationality, norm internalization and identity reinforcement. Revisiting the classics supports the hypothesis of a bipolarity of strategical principles governing fluctuating reproductive behaviour. In particular, dialectics between the two endogenous strategies — economic rationality and identity rationality — suggests the use of the Volterra-Kostitsin predator-prey model as a metaphor to account for fertility waves.     

The contribution of network research to managerial culture and practice

Although research on social networks has gained significant influence in the academic world, several factors seem to have lowered its echo in the business world. It is still unclear how this fast-growing stream of research has translated into solid implications for managerial action and decision making. Based on a review of recent research, this paper attempts to provide evidence that network research does have practical relevance. We focus on five areas where network research has introduced new angles and renewed the understanding of how organizations should tackle management issues. We also suggest directions for future research, with the same objective of placing the emphasis on strengthening the contribution of the approach to management practices.     

Look What's Back! Institutional Complexity,Reversibility and the Knotting of Logics

Through a comparative historical study of community pharmacy in the UK, Italy, Sweden and the USA, the authors examine what happens to institutional arrangements designed to resolve ongoing conflicts between institutional logics over extended periods of time. It is found that institutional arrangements can reflect the heterogeneity of multiple logics without resulting in hybridization or dominance. Because logics remain active, similar conflicts can reappear multiple times. It is found that the durability of the configurations of competing logics reflects the characteristics of the polities in which fields are embedded. The dominance of any societal institutional order leads to more stable field‐level arrangements. The authors suggest that the metaphor of institutional knots and the related image of institutional knotting are useful to capture aspects of this dynamic and to foreground the discursive and material work that allows multiple logics to coexist in local arrangements with variable durability.