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Se realizó un estudio quasi experimental en 25 pacientes que acudieron al servicio de Ortodoncia de la Clínica Estomatológica Docente Manuel Angulo Farrán, en el período comprendido de noviembre de 2003 a noviembre de 2004, con el propósito de contribuir a la terapéutica de las mordidas cruzadas posteriores en dentición mixta, utilizando el Quadhélix; teniendo en cuenta el tipo de mordida cruzada (unilateral o bilateral), el número de dientes cruzados, el sexo y su relación con el tiempo de curación. Del total de pacientes examinados, prevaleció la mordida cruzada bilateral con un 52 por ciento, así también, fue mayor el porcentaje de niños con dos a tres dientes cruzados (64 por ciento), con predominio del sexo masculino (56 por ciento). Con la utilización del Quadhélix no se encontraron diferencias significativas en cuanto al tiempo en que se alcanzaron los objetivos propuestos y el tipo de mordida cruzada, tampoco hubo relación entre el número de dientes cruzados y el sexo con respecto al tiempo de tratamiento. El Quadhélix fue efectivo en el 88 por ciento del total de la muestra, lo que evidencia su efectividad en el tratamiento de las mordidas cruzadas posteriores en el período de dentición mixta...(AU)

A quasi- experimental study in 25 patients that assisted to Orthodontics Service at Manuel Angulo Farran, Teaching Stomatology Clinic, was carried out, from November 2003 to November 2004, aimed at contributing to therapeutics of posterior cross bites in mixed dentition, through Quadhélix method, taking into account the type of cross bite (unilateral or bilateral), the number of cross teeth , the sex and its relation with the time of healing. From the sample predominated 52 percent with bilateral cross bite , as well as the higher percent of children with 2 or 3 cross teeth (64 percent), being male sex the prevailing one (56 percent).With the use of the Quadhelix there were no significant differences regarding the type of cross bite.There was no relation between the number of cross teeth and the sex related with the time of treatment. The Quadhelix was effective in 88 percent of the sample that evidence its effectiveness in the treatment of posterior cross bites during the mixed dentition...(AU)

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RESUMEN

Mate searching in crustaceans depends on different communicational cues, of which chemical and visual cues are most important. Herein we examined the role of chemical and visual communication during mate searching and assessment in the rock shrimp Rhynchocinetes typus. Adult male rock shrimp experience major ontogenetic changes. The terminal molt stages (named "robustus") are dominant and capable of monopolizing females during the mating process. Previous studies had shown that most females preferably mate with robustus males, but how these dominant males and receptive females find each other is uncertain, and is the question we examined herein. In a Y-maze designed to test for the importance of waterborne chemical cues, we observed that females approached the robustus male significantly more often than the typus male. Robustus males, however, were unable to locate receptive females via chemical signals. Using an experimental set-up that allowed testing for the importance of visual cues, we demonstrated that receptive females do not use visual cues to select robustus males, but robustus males use visual cues to find receptive females. Visual cues used by the robustus males were the tumults created by agitated aggregations of subordinate typus males around the receptive females. These results indicate a strong link between sexual communication and the mating system of rock shrimp in which dominant males monopolize receptive females. We found that females and males use different (sex-specific) communicational cues during mate searching and assessment, and that the sexual communication of rock shrimp is similar to that of the American lobster, where females are first attracted to the dominant males by chemical cues emitted by these males. A brief comparison between these two species shows that female behaviors during sexual communication contribute strongly to the outcome of mate searching and assessment.

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