Mixture inverse Gaussian for unobserved heterogeneity in the autoregressive conditional duration model

In this paper, we assume that the duration of a process has two different intrinsic components or phases which are independent. The first is the time it takes for a trade to be initiated in the market (for example, the time during which agents obtain knowledge about the market in which they are operating and accumulate information, which is coherent with Brownian motion) and the second is the subsequent time required for the trade to develop into a complete duration. Of course, if the first time is zero then the trade is initiated immediately and no initial knowledge is required. If we assume a specific compound Bernoulli distribution for the first time and an inverse Gaussian distribution for the second, the resulting convolution model has a mixture of an inverse Gaussian distribution with its reciprocal, which allows us to specify and test the unobserved heterogeneity in the autoregressive conditional duration (ACD) model.

Our proposals make it possible not only to capture various density shapes of the durations but also easily to accommodate the behaviour of the tail of the distribution and the non monotonic hazard function. The proposed model is easy to fit and characterizes the behaviour of the conditional durations reasonably well in terms of statistical criteria based on point and density forecasts.     

<Emphasis Type="BoldItalic">MAD-STEC</Emphasis>: a method for multiple automatic detection of space-time emerging clusters

Crime or disease surveillance commonly rely in space-time clustering methods to identify emerging patterns. The goal is to detect spatial-temporal clusters as soon as possible after its occurrence and to control the rate of false alarms. With this in mind, a spatio-temporal multiple cluster detection method was developed as an extension of a previous proposal based on a spatial version of the Shiryaev–Roberts statistic. Besides the capability of multiple cluster detection, the method have less input parameter than the previous proposal making its use more intuitive to practitioners. To evaluate the new methodology a simulation study is performed in several scenarios and enlighten many advantages of the proposed method. Finally, we present a case study to a crime data-set in Belo Horizonte, Brazil.     

Contact between birth parents and children in kinship care in a sample from Spain

Within the context of kinship care, the main objectives of this work are to study the characteristics of contact between foster children and their birth parents, and their relationship with key variables of fostering, the children and their kinship caregivers. The sample included 189 children from Spain and their kinship families. A semi‐structured placement interview and two scales relating to the child–caregiver relationship and child's psychological adjustment were used with the kinship families. The results revealed a significant percentage of foster children who had no family contact. Various visit types, frequencies and durations were described. Kinship care with contact, compared with placements without contact, was frequently characterized by the absence of professional supervision, and an affectionate child–caregiver relationship; moreover, children with contact were perceived to have fewer serious behaviour and socio‐emotional problems and a greater probability of family reunification. The regression analysis showed that the main predictors for how caregivers assessed contact were the children's emotional reaction during visits and the quality of the relationship between the kinship families and the birth parents. These results suggest the need for further research about contact, which will certainly have a major impact on professional intervention with these families.     

Psychosocial Well-Being of Young People Who Participated in a Support Group Following the Loss of a Parent to Cancer

Despite the evidence of unmet support needs among young people who have lost a parent to cancer, only a few support group initiatives have been reported. This observational prospective study explored the psychosocial well-being of young people who participated in support groups at a Swedish specialist palliative care setting. On three occasions, 29 participants, aged 16–28 years, answered questionnaires covering characteristics of the participants, circumstances of the losses, psychosocial well-being of the young people, and their own assessment of the support groups. The support groups attracted mostly young women who were often unprepared for the loss. The living arrangements differed between younger and older participants; however, the loss-related variables did not differ. Significant positive changes were found regarding a sense of meaning in their future life and life satisfaction. The helpfulness of the group was assessed as high/very high and the group brought a valuable fellowship with others in a similar situation. Universality and beneficial interactions were reported and strengthened psychosocial well-being developed over time. This change, according to the young people themselves, may be attributed to the group support. The findings are useful for planning interventions to support young people in bereavement in order to enhance their psychosocial well-being.     

Fostering Environmental Integration in Public Aid: Influence of Interactions Between Environmental NGOs and Aid Donors

In order to ensure sustainable development, aid donors need to improve the environmental effectiveness of their whole activity. This improvement seems to be influenced by their interactions with environmental NGOs (ENGOs). Faced with a diversity of interactions between these two kinds of actors, a strategic typology is proposed here to describe this multiplicity and, by doing so, to consider their environmental impact. Four relational postures have been identified: (i) external advocacy and (ii) the cooperation–criticism focus on the antagonistic link that exists between environment and development; (iii) environmental collaboration, and (iv) service provision, which focus on synergies that can exist between environment protection and development issues. Win–win solutions need to be continuously sought and enhanced. However, ENGOs and donors are called to recognize the necessity of maintaining a critical position in actors’ interactions vis-à-vis the implementation of development activities that are detrimental for the environment.     

Individual Pension Plans in Spain: How Expected Change in Future Income and Liquidity Constraints Shape the Behavior of Households

Understanding the motives that underlie Spaniards’ retirement saving decisions is important because many, if not most, future retirees will need to rely on personal savings to maintain a decent standard of living. The governor of the Bank of Spain has stated recently that the current public pension system will not guarantee an adequate pension to the citizens, advising to save now for retirement. In this debate on public pensions, and the complementary role that private pensions might play in Spain, this article has shed light on the decision of Spanish households to engage in individual pension plans and it has identified which factors determine the total amount saved in such retirement plans. Using micro data from the Bank of Spain (Survey of Household Finances 2011), the analysis has revealed that the expectations of lower future income, along with preferences for the financial risk and education, exert an important influence on the likelihood of enrolling in a private pension plan. University education minimizes the myopic behavior of households in the sense of making them more forward-looking and cautious in the face of their future well-being. Additionally using Heckman’s methodology to correct for the problem of selection bias, our results have revealed that liquidity constraints affect negatively the total amount of money saved for retirement.