Multivariate linear regression with non-normal errors: a solution based on mixture models

In some situations, the distribution of the error terms of a multivariate linear regression model may depart from normality. This problem has been addressed, for example, by specifying a different parametric distribution family for the error terms, such as multivariate skewed and/or heavy-tailed distributions. A new solution is proposed, which is obtained by modelling the error term distribution through a finite mixture of multi-dimensional Gaussian components. The multivariate linear regression model is studied under this assumption. Identifiability conditions are proved and maximum likelihood estimation of the model parameters is performed using the EM algorithm. The number of mixture components is chosen through model selection criteria; when this number is equal to one, the proposal results in the classical approach. The performances of the proposed approach are evaluated through Monte Carlo experiments and compared to the ones of other approaches. In conclusion, the results obtained from the analysis of a real dataset are presented.     

A tobit model with garch errors

In the context of time series regression, we extend the standard Tobit model to allow for the possibility of conditional heteroskedastic error processes of the GARCH type. We discuss the likelihood function of the Tobit model in the presence of conditionally heteroskedastic errors. Expressing the exact likelihood function turns out to be infeasible, and we propose an approximation by treating the model as being conditionally Gaussian. The performance of the estimator is investigated by means of Monte Carlo simulations. We find that, when the error terms follow a GARCH process, the proposed estimator considerably outperforms the standard Tobit quasi maximum likelihood estimator. The efficiency loss due to the approximation of the likelihood is finally evaluated.     

The Impacts of the Basel II Accord on the Concentration of the Entrepreneurial and Banking System

From the econometric analysis model, even though based on the US economy, one deduces the existence of an important correlation between the intervened changes in the role of banks’ prudential capital and in merger and acquisition dealings: the latter have increased, at least in number, after the reviewing of prudential capital requirements in favour of better structured banking organizations. The analysis of the Italian entrepreneurial and banking system shows a country characterised by small-scale enterprises with meagre growth capability (even though the Accord, paradoxically, is meant to facilitate the granting of loans to the development of small-scale enterprises), but also by the great expanding potential of banking enterprises that, contrarily to the other productive entities, can count of high re-investible margins and, consequently, of wide capabilities of investing in private equity.      

It Ought to Be a Crime: Criminalizing Human Rights Violations

In this article we propose that distinctions between human rights violations and violations of humanitarian law are substantively groundless. Human beings are entitled to live their lives with dignity and security, entitled to their freedoms. There remain, however, practical problems: human rights law and humanitarian law are distinct traditions with their own separate venues for judicatory review. They are also different in the popular imagination. We suggest ways that these distinctions can be dissolved.     

Multiple Family Group Therapy in a Drug and Alcohol Rehabilitation Centre

In the last decade there has been increasing interest in working systemically with groups of families. Multiple family groups (MFGs) have been used in mental health settings with schizophrenia, eating disorders and drug and substance abuse. This article describes the MFG program used in Higher Ground Alcohol and Drug Rehabilitation Trust, a rehabilitation centre in Auckland, (New Zealand). Higher Ground provides an 18‐week residential therapeutic program for people with a severe substance abuse disorder. The MFG in Higher Ground focuses on developing better communication patterns and better boundaries between family members, fostering mutual support, and promoting self‐responsibility.     

Rethinking Historical Reproductive Change: Insights from Longitudinal Data for a Spanish Town

A set of linked reproductive histories taken from the Spanish town of Aranjuez between 1871 and 1950 is used to address key issues regarding reproductive change during the demographic transition. These include the role of child survival as a stimulus for reproductive change, the use of stopping and/or spacing strategies to achieve reproductive goals, and the timing of change. Straightforward demographic measures are used and robust results are achieved. Initial strategies of fertility limitation are shown to exist but are inefficient, are mostly visible during the latter part of the reproductive period, are designed mostly to protect families from the effects of increases in child survival, and are based almost entirely on stopping behavior. As mortality decline accelerates, strategies become much more efficient, are visible at the outset of married life, include spacing behavior, and eventually lead to important declines in completed family size. The results of this study have implications for our understanding of the demographic transition both in historical Europe and in other regions of the world.     

The random intrinsic fast initial response of one-sided CUSUM charts

This article analyses the performance of a one-sided cumulative sum (CUSUM) chart that is initialized using a random starting point following the natural or intrinsic probability distribution of the CUSUM statistic. By definition, this probability distribution remains stable as the chart is used. The probability that the chart starts at zero according to this intrinsic distribution is always smaller than one, which confers on the chart a fast initial response feature. The article provides a fast and accurate algorithm to compute the in-control and out-of-control average run lengths and run-length probability distributions for one-sided CUSUM charts initialized using this random intrinsic fast initial response (RIFIR) scheme. The algorithm also computes the intrinsic distribution of the CUSUM statistic and random samples extracted from this distribution. Most importantly, no matter how the chart was initialized, if no level shifts and no alarms have occurred before time τ?>?0, the distribution of the run length remaining after τ is provided by this algorithm very accurately, provided that τ is not too small.     

Extreme value regression models: a useful reparameterization for the survival function

In this paper, we consider some aspects of accurate approximate inferences for the survival function at a specifed time t 0 , considering extreme value regression models using a modified form of reparameterization proposed by Guerrero and Johnson, and exploring a non-normality measure for likelihood functions and posterior densities introduced by Kass and Slate. We illustrate the proposed methodology, considering a lifetime data set with two treatments introduced by Lee.