Evaluating public health perspectives of sexually transmitted diseases: The need for further research

While sexuality is the focus of extensive research, the concept has not been adequately defined. In this paper, sexuality is defined as the individual capacity to respond to physical experiences which are capable of producing body‐centered genital excitation, that only subsequently becomes associated with cognitive constructs (either anticipatory for new experiences or reflective of past experiences) independent of ongoing physical experiences. The discussion focuses on four components of this definition: that sexuality is an individual capacity, is experiential, is body‐oriented, and is directed toward genital excitation.     

Bewertung intertemporaler Abh?ngigkeiten zwischen IT-Projekten

Companies often decide in favour of IT investments (especially IT infrastructure investments) only because these investments build the foundation for more lucrative follow-up investments. Those intertemporal interdependencies among IT projects have to be considered within the scope of a value-based IT portfolio management. Therefore, current literature suggests the use of real options analysis??and therefore the application of option pricing models such as the binomial model or the Black-Scholes model. Both models require a complete market. However, because IT projects are characterized by project specific risks, which cannot be duplicated on a capital market, the forthright application of these models is problematic. This issue has been addressed within the scope of the discrete binomial model so far. In this paper we transfer these findings to the Black-Scholes model. Furthermore, we apply this approach to a real case and illustrate how a correct consideration of project specific risks using the Black-Scholes model can affect investment decisions.     

Nonprofit management in Europe and Asia

The State and NGOs: Perspective from Asia, edited by Shinichi Shigetomi. Singapore: Institute of Southeast Asia Studies, 2002. $28.50 cloth. The Emergence of Social Enterprise, edited by Carlo Borzaga and Jacques Defourny. New York: Routledge, 2001. $120.00 cloth.     

HIGH SCHOOLS AND CRIME: A REPLICATION

Using Cleveland data, we replicate Roncek and LoBosco's study of the effect of proximity to San Diego's high schools on crime in their surroundings. We also examine a major alternative hypothesis whether having other non-residential land uses in the schools' surroundings accounts for crime in these areas. Our findings closely parallel theirs. Proximity to public high schools only increases crime on city blocks which are immediately adjacent to the schools. Second, the size of a school's enrollment is not important for explaining crime in its surroundings. The analysis of non-residential effects supports Roncek and LoBosco's claim that crime effects are due solely to the presence of public high schools, although other land uses affect crime near private high schools. While there are differences in the exact magnitudes of the effects, the substance of their findings for San Diego generalizes well to a very different city. More generally, we argue that Wirth's early arguments about the effect of urbanism on impeding social control can be extended to the residential areas within the city.     

Supersaturated design including an orthogonal base

Recently, many supersaturated designs have been proposed. A supersaturated design is a fractional factorial design in which the number of factors is greater than the number of experimental runs. The main thrust of the previous studies has been to generate more columns while avoiding large values of squared inner products among all design columns. These designs would be appropriate if the probability for each factor being active is uniformly distributed. When factors can be partitioned into two groups, namely, with high and low probabilities of each factor being active, it is desirable to maintain orthogonality among columns to be assigned to the factors in the high-probability group. We discuss a supersaturated design including an orthogonal base which is suitable for this common situation. Mathematical results on the existence of the supersaturated designs are shown, and the construction of supersaturated designs is presented. We next discuss some properties of the proposed supersaturated designs based on the squared inner products.