Influence of social factors on sugary products behavior in 4-year-old children with regard to dental caries experience and information at child health centers.

The aim was to analyze the steering effects of 15 social factors on sugary products behavior at 4 years of age in 177 children. The parents had in most cases received information on dental health care at child health centers, with due respect to the level of caries among the children, who were classified as 'healthy' (no caries experience) (n = 83) or 'diseased' (caries experience) (n = 84). The parents filled in a mailed diet history form. Only sugary products unsuitable from a cariologic point of view were considered. The products were given scores reflecting the frequency of intake. The social factors were social background, family, information, and conceptual factors. By means of multiple regression analysis, explanatory values of the social variables for sugary products behavior were estimated. For the total material, 13% of the variance was explained by all variables combined. Among the social background factors, 'parents' age' was statistically significant (p < 0.05). Among family factors, 'day-care mainly at home' and 'oldest child' were the most important. All information factors proved to be nonsignificant. Of the conceptual factors, only 'importance of genetic factors' was statistically significant. For the healthy group 26% of the variance was explained by all variables. 'Mother's age', 'importance of genetic factors', and 'oldest child' were statistically significant. For the diseased group all variables were nonsignificant. Explanatory values were negligible. The important conclusions were that very few traditionally conceived social variables seem to influence 4-year-old children's sugar behavior. Parents of children with caries appear to be a heterogeneous group with an irrational behavior.

A physiological comparison of forward vs reverse wheelchair ergometry.

The purpose of this study was to compare metabolic and cardiopulmonary responses for forward wheelchair ergometry (FOR) and reverse wheelchair ergometry (REV) at equal power outputs (PO) levels. Moderately active able-bodies (N = 21) subjects exercised at 3-min stages at PO levels of 15, 20, 25, and 30 W for each mode of ergometry. Oxygen uptake (VO2), pulmonary ventilation (VE), respiratory exchange ratio (RER), heart rate (HR), percent net mechanical efficiency (ME), revolutions per minute (RPM) and strikes per minute (SPM) were determined at each PO level. With the exception of RER, all the physiological responses (VO2, VE, and HR) were higher for FOR exercise (P < 0.05) than REV exercise. ME increased with PO and was higher (P < 0.05) for REV than FOR at each PO level. SPM values for the REV were lower (P < 0.01) by almost half of that for the FOR exercise, although RPM remained constant between modes during all four stages. In general, these data suggest that reverse wheelchair ergometry is physiologically more efficient than conventional wheelchair ergometry and should be studied further as an alternative method for wheelchair ambulation.

Prey selection by mosquitofish (Gambusia affinis) in California rice fields: effect of vegetation and prey species.

Mosquitofish are widely used for biological control of mosquito larvae in rice fields, but the presence of different types of vegetation or alternative arthropod prey affects the performance of the fish. Feeding experiments were conducted in 4 rice field vegetation zones. Overall, predation was maximal in young and mature rice, moderate in the submerged naiad vegetation, and minimal in areas of open water. A preference for fourth instar Culex tarsalis mosquito larvae over Daphnia pulex and the amphipod Hyalella azteca was demonstrated. Second nymphal stage corixid bugs, Cenocorixa sp., were avoided; a similar notonectid, Buenoa sp., was eaten in amounts comparable to the D. pulex and H. azteca. No preference between Culex tarsalis and Anopheles freeborni mosquito larvae was detected.

Comparative larvivorous performances of mosquitofish, Gambusia affinis, and juvenile Sacramento blackfish, Orthodon microlepidotus, in experimental paddies.

Mosquitofish, Sacramento blackfish, or combinations of both species were stocked in experimental paddies. Cultured Culex tarsalis larvae, stocked weekly into each paddy, and wild Anopheles freeborni larvae were counted by dipping. At the end of the 12 week experiment, paddies were drained and the remaining fish and visible invertebrates counted. Data show the highest number of mosquito larvae in the blackfish-stocked paddies. This low larvivorous ability of blackfish may result from their rapid growth to ca. 70 mm standard length and a consequent shift to a filtering mode of feeding. Although blackfish populations decreased from one-third to one-half of their stocked levels and mosquitofish populations increased to very high levels, mosquito control seemed to be a function of species rather than just the number of predatory fish. The lower number of larvae in the control paddies compared with the blackfish paddies might be attributable to predatory invertebrate communities.