Exploring ancestral phenotypes and evolutionary development of the mammalian middle ear based on Early Cretaceous Jehol mammals

We report a new Cretaceous multituberculate mammal with 3D auditory bones preserved. Along with other fossil and extant mammals, the unequivocal auditory bones display features potentially representing ancestral phenotypes of the mammalian middle ear. These phenotypes show that the ectotympanic and the malleus-incus complex changed notably during their retreating from the dentary at various evolutionary stages and suggest convergent evolution of some features to extant mammals. In contrast, the incudomalleolar joint was conservative in having a braced hinge configuration, which narrows the morphological gap between the quadroarticular jaw joint of non-mammalian cynodonts and the incudomalleolar articulations of extant mammals. The saddle-shaped and abutting malleus-incus complexes in therians and monotremes, respectively, could have evolved from the braced hinge joint independently. The evolutionary changes recorded in the Mesozoic mammals are largely consistent with the middle ear morphogenesis during the ontogeny of extant mammals, supporting the relation between evolution and development.     

Regular class teachers' perceptions of transition programs for EMR students and their impact on the students

This study was designed to obtain the perceptions of regular class teachers who taught children who had been in EMR programs, but had been decertified (D) and returned to regular classes in response to court cases and recent legislation. A cohort of regular class (RC) students were selected for comparative purposes. It was found that D students were placed into low ability classes; yet, teachers perceived D subjects to be significantly lower than RC students in both academic achievement and social acceptance. Only a small proportion of teachers indicated that the enrollment of D students had much impact on the regular class instructional program. However, the teachers were rather critical of the services received under the auspices of a transitional program, indicating in large part that the services were either not apparent or ineffective.     

Ethical issues of behavior modification research in schools

Behavior modification research in the classroom was examined by the National Commission for the Protection of Human Subjects because of the increasingly widespread use of behavioral procedures in the schools, the effectiveness of these procedures in changing academic and social behavior, and the consequent concern about potential misuse. In order to foster the responsible use of behavior modification procedures in the schools on a practical as well as a research basis, the following ethical issues being considered by researchers and the involved public are discussed: informed consent, determination of classroom goals, legitimacy of rewards and aversive controls in the classroom, conceptions of behavior modification as manipulative and mechanistic, who can implement the procedures, research design, and accountability. The authors conclude that the issues regarding protection of human subjects in behavior modification research are no different from other treatment-oriented research with children. However, the high degree of parental and teacher involvement in both research and practice requires shared responsibility for the prevention of misuse of behavior modification procedures.     

Does living with a female head-of-household affect the arithmetic achievement of black fourth-grade pupils?

It was the purpose of this investigation to examine the effects of living with a male or female head-of-household upon the arithmetic performance of fourth graders. No significant differences were found in mean scores between male and female pupils. Significant differences were found favoring those pupils living with male heads-of-households, particularly for female pupils and for pupils with IQ scores greater than 100. These findings should not be considered as simple cause and effect relationships, but rather as indicative of potential difficulty for some pupils.     

Effect of spatial titration on task performance

A reinforcement schedule and spatial titration method were used to determine task-reinforcement area separation most preferred and effective in two third-grade boys. Errors in task performance decreased task-reinforcement area separation, while correct responses in task performance increased task-reinforcement area separation. Zero task-reinforcement area separation was most preferred and effective in producing high task performance.