Relation between active mediation,exposure to Daniel Tiger’s Neighborhood,and US preschoolers’ social and emotional development

This study explored the relationship between active mediation, exposure to Daniel Tiger’s Neighborhood, and key indicators of preschoolers’ social and emotional development. One hundred and twenty-seven children aged 2–6 either watched or did not watch 10 episodes of Daniel Tiger’s Neighborhood over a two-week period. Results revealed that preschoolers who watched the program exhibited higher levels of empathy, self-efficacy, and emotion recognition when their regular TV-watching experiences are frequently accompanied by active mediation. This was especially true for younger preschoolers and preschoolers from low-income families. Implications for policy-makers, parents, producers of prosocial programming, and educators are discussed.     

An evaluation of Gambusia affinis and Bacillus thuringiensis var. israelensis as mosquito control agents in California wild rice fields

The mosquito control potential of the mosquitofish and Bacillus thuringiensis var. israelensis (Bti) were evaluated in experimental wild rice fields in Lake County, California. Fields were assigned one of six treatment: control, 1.1 kg/ha G. affinis, 3.4 kg/ha G. affinis, Bti only (6 kg/ha Vectobac granules), 1.1 kg/ha G. affinis plus Bti and 3.4 kg/ha G. affinis plus Bti. Gambusia affinis, at both release rates, significantly reduced the mosquito population at densities exceeding 100 fish/minnow trap. Treatments with Bti significantly reduced larval population; however, the populations in the fields without fish rebounded to pretreatment levels within two weeks. In fields stocked with G. affinis and treated with Bti, populations remained low after Bti treatment. Nontarget populations of arthropods were significantly lower in fields stocked with G. affinis than in fields without fish on one or more sampling dates.     

Ultrastructure of the integument of first-instar Hypoderma lineatum and H. bovis (Diptera: Oestridae)

The ultrastructure of the integument of newly hatched, 60-d-old (in vitro-cultured) and 6-7-mo-old (recovered from the host) first-instar cattle grubs, Hypoderma lineatum (Villers) and H. bovis (L.), was studied. Changes in the cuticle during development of the first instar included increased thickness of the procuticle (0.8-1.4 to 7.5-7.9 microns) with an accompanying increase in number of lamellae (4-7 to 35-40), increased thickness of epicuticle (0.11-0.24 to 0.92 microns), and development of new epicuticle layers. The epithelial cells in newly hatched larvae also changed with age when compared with those in culture and those recovered from hosts. These changes included the appearance of dense plaques on the apical cell membrane and an increase in the folding of the basal cell membranes, with an accompanying increase in the amount of extracellular space. The basement membrane, separating epithelial cells from the hemocoel, also increased in thickness during the first instar. These changes reflect developments required to accommodate increased size but, in the case of the epithelial cells, suggest altered function. Ruthenium red staining on the cuticular surface of larvae cultured in vitro was indicative of the presence of negatively charged molecules, which may influence the host recognition and response capabilities.