Modeling and exploiting behavior patterns in dynamic environments

This paper presents a new approach to improving the effectiveness of autonomous systems that deal with dynamic environments. The basis of the approach is to find repeating patterns of behavior in the dynamic elements of the system, and then to use predictions of the repeating elements to better plan goal directed behavior. It is a layered approach involving classifying, modeling, predicting and exploiting. Classifying involves using observations to place the moving elements into previously defined classes. Modeling involves recording features of the behavior on a coarse grained grid. Exploitation is achieved by integrating predictions from the model into the behavior selection module to improve the utility of the robot's actions. This is in contrast to typical approaches that use the model to select between different strategies or plays. Three methods of adaptation to the dynamic features of the environment are explored. The effectiveness of each method is determined using statistical tests over a number of repeated experiments. The work is presented in the context of predicting opponent behavior in the highly dynamic and multi-agent robot soccer domain (RoboCup)

A cognitive model of binge drinking: The influence of alcohol expectancies and drinking refusal self-efficacy

While binge drinking-episodic or irregular consumption of excessive amounts of alcohol-is recognised as a serious problem affecting our youth, to date there has been a lack of psychological theory and thus theoretically driven research into this problem. The current paper develops a cognitive model using the key constructs of alcohol expectancies (AEs) and drinking refusal self-efficacy (DRSE) to explain the acquisition and maintenance of binge drinking. It is suggested that the four combinations of the AE and DRSE can explain the four drinking styles. These are normal/social drinkers, binge drinkers, regular heavy drinkers, and problem drinkers or alcoholics. Since AE and DRSE are cognitive constructs and therefore modifiable, the cognitive model can thus facilitate the design of intervention and-prevention strategies for binge drinking. (C) 2003 Elsevier Ltd. All rights reserved.

Usability of a mobile, group communication prototype while rendezvousing

Mobile phones are increasingly being used collaboratively by social networks of users in spite of the fact that they are primarily designed to support single users and one-to-one communication. It is not well understood how services such as group SMS, SMS-based discussion lists and mobile instant messaging (IM) will be used by mobile groups in natural settings. Studying specific instances of common styles of in situ, group interaction may provide a way to see behavior patterns and typical interaction problems. We conducted a study of a mobile, group communication probe used during a rendezvousing activity in an urban environment. Usability problems relating to group usage, phone interface design and context were identified. Several major issues included: multitasking during message composition and reading; speed of text entry; excessive demand on visual attention; and ambiguity of intended recipients. We suggest that existing mobile device designs are overly-focused on individual users to the detriment of usability for mobile groups of users. We provide recommendations for the design of future mobile, group interfaces, used in similar situations to those explored here

Early patterns of sexual activity: age cohort differences in Australia

Patterns of first sexual activity among Australians born between the 1940s and 1980s were analysed using data from a national telephone survey of 1784 adults (876 males; 908 females). Sixty-one percent of those randomly selected from the Australian electoral roll and contactable by telephone responded. Many trends, including earlier first intercourse - from 20 to 18 years (females) and 18.8 to 17.8 years (males) - were established with the 40-49 year cohort, whose sexual debut was in the late 1960s-70s. Significant age-cohort effects saw women in the contemporary (18-29 year) cohort draw level with males for age at first intercourse and first sex before age 16 and before leaving school. First intercourse contraceptive use climbed from 30% to 80'%. Condom use quadrupled to 70%. Australian age-cohort effects are remarkably consistent with those in similar western cultures: gender convergence in sexual experience and increasing avoidance of sexually transmitted disease and pregnancy. If such trends continue, positive long-term outcomes for health and social wellbeing should result.

Drug use patterns and mental health of regular amphetamine users during a reported 'heroin drought'

Aims The present study extends the findings of a pilot study conducted among regular amphetamine users in Newcastle, NSW, in 1998. It compares key features between current participants in a state capital city (Brisbane) and a regional city (Newcastle) and between the 1998 and current Newcastle sample. Design Cross-sectional survey. Setting Brisbane and Newcastle, Australia. Participants The survey was conducted among 214 regular amphetamine users within the context of a randomized controlled trial of brief interventions for amphetamine use. Measurements Demographic characteristics, past and present alcohol and other drug use and mental health, treatment, amphetamine-related harms and severity of dependence. Findings The main findings were as follows: (i) the rate of mental health problems was high among regular amphetamine users and these problems commonly emerged after commencement of regular amphetamine use; (ii) there were regional differences in drug use with greater accessibility to a wider range of drugs in a state capital city and greater levels of injecting risk-taking behaviour outside the capital city environment; and (iii) there was a significant increase in level of amphetamine use and percentage of alcohol users, a trend for a higher level of amphetamine dependence and a significant reduction in the percentage of people using heroin and benzodiazepines among the 2002 Newcastle cohort compared to the 1998 cohort. Conclusions Further longitudinal research is needed to elucidate transitions from one drug type to another and from recreational to injecting and regular use and the relationship between drug use and mental health in prospective studies among users. Implications Intervention research should evaluate the effectiveness of interventions aimed at: preventing transition to injecting and regular use of amphetamines; toward reducing levels of depression among amphetamine users and interventions among people with severe psychopathology and personality disorders; and toward reducing the prevalence of tobacco dependence among amphetamine users.

Historical and contemporary mating patterns in remnant populations of the forest tree Fraxinus excelsior L.

Genetic variation at microsatellite markers was used to quantify genetic structure and mating behavior in a severely fragmented population of the wind-pollinated, wind-dispersed temperate tree Fraxinus excelsior in a deforested catchment in Scotland. Remnants maintain high levels of genetic diversity, comparable with those reported for continuous populations in southeastern Europe, and show low interpopulation differentiation (Theta = 0.080), indicating that historical gene exchange has not been limited (Nm = 3.48). We estimated from seeds collected from all trees producing fruits in three of five remnants that F. excelsior is predominantly outcrossing (t(m). = 0.971 +/- 0.028). Use of a neighborhood model approach to describe the relative contribution of local and long-distance pollen dispersal indicates that pollen gene flow into each of the three remnants is extensive (46-95%) and pollen dispersal has two components. The first is very localized and restricted to tens of meters around the mother trees. The second is a long-distance component with dispersal occurring over several kilometers. Effective dispersal distances, accounting for the distance and directionality to mother trees of sampled pollen donors, average 328 m and are greater than values reported for a continuous population. These results suggest that the opening of the landscape facilitates airborne pollen movement and may alleviate the expected detrimental genetic effects of fragmentation.

Parental attachment and conflict behavior: Implications for offspring's attachment, loneliness, and relationship satisfaction

This study assessed the implications of parental attachment security and parental conflict behavior for offspring's relational adjustment (attachment security, loneliness, and relationship satisfaction). Further, reports of parental conflict behavior were obtained from both parents and offspring, addressing questions regarding agreement between reporters and the origin and extent of discrepant perceptions. Results revealed consistent patterns of conflict behavior and moderate agreement between reporters. However, offspring reported parental conflict behavior more negatively than parents, especially when offspring or parents were anxious about relationships. Parental attachment security had direct associations with offspring's relationship anxiety, whereas associations between parental attachment and offspring's loneliness and discomfort with closeness were mediated by parental conflict behavior. Parental conflict behavior was also associated with offspring's relationship satisfaction. The results are discussed in terms of the mechanisms involved in the intergenerational transmission of relationship difficulties.

PRN Sedation-patterns of prescribing and administration in a child and adolescent mental health inpatient service

Objective: To identify utilisation rates of prn (pro re nata) sedation in children and adolescents receiving inpatient psychiatric treatment, and to compare correlates of prn prescribing and administration. Method A retrospective chart review examined 122 medical charts from a child and youth mental health inpatient service. Results 71.3% of patients were prescribed prn sedation and 50.8% were administered prn sedation. Patients received an average of 8.0 doses of prn sedation, with 9.8% receiving 10 or more doses. Chlorpromazine and diazepam were the most commonly utilised agents. Prescribing of prn sedation was only related to use of regular medications (p < 0.01), and non-parent carers (p < 0.01). In contrast, administration of prn sedation was associated with multiple diagnoses (p < 0.01), pervasive development disorder (p < 0.01), mental retardation (p < 0.01) ADHD (p < 0.01), longer hospital admission (p < 0.01), use of atypical antipsychotics (p < 0.01) and polypharmacy (p < 0.01). Conclusions Despite lack of data to inform practice, prn sedation is widely utilised, especially in complex patients. Future research in this area needs to incorporate nurses and examine whether patients benefit from prn sedation, which drugs and dosing patterns optimise safety and efficacy, and what is the role of prn sedation in the context of other medication.

Physical activity patterns of Singaporean adolescents

The purpose of this study was to document the level of physical activity and sedentary behavior in a representative sample of Singaporean adolescents. A random sample of 1,827 secondary school students from six secondary schools (929 boys, 898 girls, mean age 14.9 +/- 1.2 yr) completed the Three-Day Physical Activity Recall (3DPAR) self-report instrument. Approximately 63% of Singaporean high school students met current guidelines requiring 60 min of moderate to vigorous physical activity daily. Just over half (51.6%) met the guideline calling for regular vigorous physical activity. Across all grade levels, boys were consistently more active than girls. More than 70% of Singaporean high school students exceeded the recommended 2 hours per day of electronic media use. Collectively, these findings suggest that a significant proportion of Singaporean adolescents are not sufficiently active and are in need of programs to promote physical activity and decrease sedentary behavior.