Eletronic publishing and chemical text processing - II. Character and vector representations of chemical structures
Abstract Fragments for two-dimensional chemical structure diagrams can be represented by either characters or vectors. The relative merits of the two approaches are considered and it is shown that the vector representation is clearly superior.
Tools for Communicating with Chemical Information: A Cognitive Engineering Analysis
A major challenge for human factors is designing specialized systems to mesh with the domain expertise and mental representations of the system users. Systems for computational chemistry are an important example. Chemists use chemical structure diagrams (CSDs) as part of their basic language of communication, along with chemical formulae, narrative text, graphs and charts. Current computer tools for communicating with CSDs in written contexts are often found by chemists to be incomplete, difficult to use, and offering inappropriate functionality. This problem arises from ineffective human computer-interfaces that, in turn, can be traced to a lack of understanding on how skilled chemists use, think about, and communicate with CSDs. A formal cognitive human factors analysis is applied to address this deficiency. The analysis is developed through critical incident interviews, question-answering protocols, and thinking aloud protocols. Its results include a GOMS-type cognitive model of the drawing/manipulation process and of the conceptual strucutres underlying that process. Existing CSD drawing tool interfaces can be seen to provide little support for the conceptual structues or cognitive processes identified. The model developed in this research is being used to develop a user-oriented HCl for chemical structure manipulation systems.
Exposure to violence in incarcerated youth from the city of São Paulo.
OBJECTIVE
This study aimed to determine the extent of exposure to community violence among delinquent Brazilian youth in the 12-month period prior to their incarceration and to identify factors associated with this exposure.


METHOD
With an oversampling of girls, a cross-section of youth under 18 years of age from juvenile detention units in the city of São Paulo, Brazil completed a structured interview. Key items related to exposure to violence (witnessed and experienced) were drawn from the Social and Health Assessment questionnaire to cover the 12-month period prior to incarceration.


RESULTS
Participants (n = 325, 89% boys) reported high rates of exposure to violence with largely similar levels for boys and girls. Being threatened with physical harm, being beaten or mugged and/or shot at were the most common forms of violence experienced. After controlling for demographic and family variables, the fact of having peers involved in risk behavior, easy access to guns and previous involvement with the justice system were associated with witnessed violence; whereas having slept on the street was the only variable associated with experienced violence.


CONCLUSION
This group of youth was exposed to high levels of violence and other adverse experiences. Future research should examine the effectiveness of strategies aimed at reducing the exposure to violence of high-risk youth.