Rodents,evolution, and prehistory

The rodents, especially voles, evolved very rapidly during the Quaternary era. Their remains, particularly the teeth, were fossilised by the thousand in prehistoric deposits. The sites can be dated from the degree of evolution attained by the teeth. Since rodents are closely adapted to their biotopes and live under well defined climatic conditions, they are extremely valuable for reconstructing the landscapes and climates of prehistory. In many cases, a single rodent tooth can be used to assess the age of a human skull or a prehistoric settlement, and throw light on the environment and climate of the time.     

Predicting Parent-Child Differences in Perceptions of How Children Use the Internet for Help With Homework,Identity Development,and Health Information

Bioecological systems theory provides a framework to understand how factors in the child's environment contribute to parent-child differences in estimations of how often children are helped by their Internet use. A national sample survey of 456 matched parent-child pairs investigated how parents-child relational factors, parental attitudes toward the Internet, and the bio-ecology of the child, are related to differing perceptions of the frequency of using the Internet to seek help with homework assignments, to aid in identity development, and to find health information. While previous research shows that parents underestimate risky online behaviors, we investigate whether parent-child differences will emerge in regards to how often the child engages in the behaviors under investigation here. The findings show that parents overestimate these online activities, suggesting they are biased in their estimations. Parent-child relational factors emerged as predictors of parental overestimation for each of these online activities, with trust perceptions as the most consistent predictor. Parental attitudes toward the Internet predicted parent-child differences in perceptions of how frequently the child used the Internet for help with homework and identity development, while the bioecology of the child was only predictive in the case of using the Internet for help with homework.     

CORRELATES OF CONDUCT PROBLEMS AND DEPRESSION COMORBIDITY IN ELEMENTARY SCHOOL BOYS AND GIRLS RECEIVING SPECIAL EDUCATIONAL SERVICES

There is limited empirical research on the correlates of conduct problems (CP) and depression comorbidity during childhood. This study investigated 479 elementary school children (48.2% girls). It compared children with comorbidity to children with CP only, depression only, and control children on individual, academic, social, and family characteristics. The study also analyzed gender differences in the associations between correlates and comorbidity. Multinomial logistic regression results revealed that children with CP and depression had higher levels of anxiety and more school difficulties than children with CP only, more social difficulties and more severe attention deficit and hyperactivity disorder (ADHD) symptoms than children with depression only, and more difficulties in all domains than control children. Girls with CP and depression presented a particularly negative profile, including lower school abilities than CP and control girls, and lower social skills and more severe ADHD symptoms than control girls.  Implications for evaluation and intervention planning are discussed.