published_or_final_version / Social Work / Master / Master of Social Work

published_or_final_version / Chinese / Master / Master of Arts

In most birds, changing photoperiods from winter to spring and from summer to fall have two consequences: increased feeding followed by migratory activity. To date, the neural system controlling the activation of migratory activity remains unknown, though behavioral observations point to a possible mechanism. During the migration season, diurnal songbirds show extensive disruption of their sleep/wake cycle, sleeping during the day and flying at night. In mammals, similarly altered cycles of activity result from blocking orexin expression in the hypothalamus. It is possible that decreased orexin expression is associated with migratory activity in songbirds. In addition, changes in ingestive behaviors and fuel availability may also be associated with disruptions in the sleep/wake cycles of migratory birds. The studies in my dissertation will address these issues through three main specific aims. First, I will determine that orexin systems are conserved in vertebrate brains. Second, I will test the association between orexin and migratory activity in songbirds. Third, I will confirm the association between fuel availability, orexin expression and migratory activity in songbirds. / text

Past research has shown classroom lessons incorporating physical activity (10-15 minutes in duration) to improve on-task behavior in children (Mahar, 2006; Grieco, Bartholomew & Jowers, 2009). However, no study to date has examined the levels of physical activity required to elicit this response. As such, the present study was designed to assess the effects of physically active, academic lessons of varying intensity, set in game-type format, on academic engagement of preadolescent children in the classroom setting. Time spent on-task (measured through direct observation) served as the primary outcome variable and assessed by means of a two (time: pre-, post-lesson) x four [condition: inactive lesson (physical activity control); sedentary academic game (interest control); low-to-moderate intensity physically active academic game; moderate-to-vigorous intensity physically active academic game] repeated measures design. Participants were third, fourth and fifth grade children from two elementary schools in central Texas (7 to 11 years of age). Physical activity was measured using Actigraph GT1M accelerometers (Fort Walton Beach, FL). Demographic data were collected for each participant on gender, age, ethnicity, height and weight (BMI calculated). Results indicated that the students’ TOT decreased significantly after a traditional seated control lesson. TOT did not change following the inactive control game. Thus, the competitive, seated game was sufficient to prevent the reduction in TOT that followed the traditional, seated control. In contrast, both physically active games were sufficient to increase TOT. Both had a significant increase in TOT relative to each control condition. In addition, the effect of the MVPA game was nearly three times the effect of the LMPA game. / text

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