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Biomedical subjects

R Beckman

Publications and source records attributed to R Beckman.

6 recordsLinked to original sources

Contraceptive behavior among sexually active Hispanic adolescents.

The purpose of this study was to examine those factors associated with the contraceptive behavior of a national representative sample of Hispanic female adolescents. The subjects included all (n = 85) unmarried, sexually active Hispanic women, aged 15 to 19, from the 1982 National Survey of Family Growth. Contraceptive behavior was measured on a normalized scale, ranging from oral contraceptives to no contraception. Mexican/American and Central/South American background females were more likely (p less than 0.031) to use effective birth control than Puerto Rican, Cuban, and other Hispanic background subjects. Twenty additional social, behavioral, and demographic variables were found to be significantly associated (p less than 0.05) with contraceptive behavior. Based on multiple regression analysis, seven of these variables were found to explain 62% (p less than 0.0001) of the variation in the contraceptive behavior of this sample. Poorer contraceptive behavior was associated with noncompliance with the initial birth control method used (33.8%), lower coital frequency (8.3%), older postmenarchial age (5.7%), failure to use birth control at first coitus (4.6%), fewer years dating (4.0%), lower frequency of church attendance (3.3%), and never having experienced a pregnancy scare (2.0%). These findings suggest that the contraceptive behavior of Hispanic female adolescents is a dynamic process that can be understood in the context of previous sexual and contraceptive behavior.

Adolescent

Orientation bias in the response of kitten LGNd neurons to moving light bars.

The orientation sensitivity to moving light bars was determined for 113 neurons in laminae A, A1 and C of the dorsal part of the lateral geniculate nucleus (LGNd) of kittens 7-42 days old. Forty neurons (35.4%) were biased to contrast orientation (OB neurons), i.e. their response to an optimally oriented bar was 2-10 times stronger than their response to a bar oriented orthogonally to the optimal. The remaining 73 neurons were not sensitive to contrast orientation. Evidence is presented that orientation bias in the LGNd develops prior to visual experience. Orientation biased responses in the LGNd strongly depended on stimulus parameters; preferred stimuli were light bars having a length of 5 degrees or more and moving at velocities slower than 5 degrees/s. Our findings suggest that the OB neurons of the LGNd could be effective in generating the early orientation sensitivity in the visual cortex.

Animals