Regression of the lateral oviducts during the larval-adult transformation of the reproductive system of Melipona quadrifasciata and Frieseomelitta varia

Toward the end of the larval phase (pre-pupa), the reproductive systems of Melipona quadrifasciata and Frieseomelitta varia workers are anatomically similar. Scanning electron microscopy showed that during this developmental phase the right and left ovaries are fused and form a heart-shaped structure located above the midgut. Each ovary is connected to the genital chamber by a long and slender lateral oviduct. During pupal development, the lateral oviducts of workers from both species become extremely reduced due to a drastic process of cell death, as shown by transmission electron microscopy. During the lateral oviduct shortening, their simple columnar epithelial cells show some signs of apoptosis in addition to necrosis. Cell death was characterized by cytoplasmic vesiculation, peculiar accumulation of glycogen, and dilation of cytoplasmic organelles such as mitochondria and rough endoplasmic reticulum. The nuclei, at first irregularly contoured, became swollen, with chromatin flocculation and various areas of condensed chromatin next to the nuclear envelope. At the end of the pupal phase, deep recesses marked the nuclei. At emergence, worker and queen reproductive systems showed marked differences, although reduction in the lateral oviducts was an event occurring in both castes. However, in queens the ovarioles increased in length and the spermatheca was larger than that of workers. At the external anatomical level, the reproductive system of workers and queens could be distinguished in the white- and pink-eyed pupal phase. The metamorphic function of the death of lateral oviduct cells, with consequent oviduct shortening, is discussed in terms of the anatomical reorganization of the reproductive system and of the ventrolateral positioning of adult worker bee ovaries. (C) 2000 Wiley-Liss, Inc.

A system of indicators for monitoring social cohesion in Latin America

Includes bibliography

Continuous torque system with control of the reaction unit

This article describes an orthodontic system used to obtain active continuous torque with movement control of both active and reactive units; the system relies on principles of the segmented technique. A cantilever system with .017 x .025-in beta-titanium alloy wire was designed to provide the desirable moment on the active unit. A transpalatal bar or a lingual arch increases the anchorage and neutralizes the side effects on the reactive unit. This technique is an efficient approach for major corrections of buccolingual inclinations of certain teeth. © 2010 American Association of Orthodontists.

The role of education in relation to employment problems

Includes bibliography

Programas de la Organización de Estados Americanos relacionados con la urbanización en América Latina = Programmes of the Organization of American States connected with urbanization in Latin America

Los documentos del Seminario fueron publicados por UNESCO en 1961 con el título: La urbanización en América Latina/Urbanization in Latin America

As diferenças entre os desempenhos escolares, a relação com os saberes e o acesso à escrita: o que dizem professores e alunos de 5. série

Pós-graduação em Educação - IBRC

Study of problems related with the establishment of motor-vehicle industries in developing countries

Information Paper, No 12

Investigation of the Effect of Sealer Use on the Heat Generated at the External Root Surface during Root Canal Obturation Using Warm Vertical Compaction Technique with System B Heat Source

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Male reproductive system of the red brocade hermit crab Dardanus insignis (Diogenidae) and its relationship to other family members

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On the morphology of the digestive system of two Moomorium ant species

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Properties of glass-ceramics obtained from crystallization of the SiO2-Al2O3-MgO-Li2O system with addition of ZrO2

This paper presents the study results with glass-ceramics obtained from base glass (MgO-Al2O3- SiO2-Li2O system) with addition of ZrO2 as nucleating agent. The glass was melted at 1650 degrees C for 3 h and at a heating rate of 10 degrees C/min. The molten glass was poured into a graphite mold to obtain monolithic samples and also in water in order to obtain particulate material. Such material was grinded and then pressed by both uniaxial and isostatic pressing methods before being sintered. Both the monolithic and pressed samples were performed under two different conditions of heat treatment so that their nucleation and crystallization occurred. In the first one, the samples were heated to 1100 degrees C with a heating rate of 10 degrees C/min. In the second one, there was an initial heating rate of 10 degrees C/min up to 780 degrees C, which was kept for 5 minutes. After that, the samples were heated to 1100 degrees C at a heating rate of 1 degrees C/min. Microhardness analyses showed that base glass presented values around 7.0 GPa. The glass-ceramics obtained from the powder sintering showed microhardness values lower than those obtained from monolithic samples. The highest hardness values were observed in the samples which were treated with two heating rates, whose values were around 9.2 +/- 0.5 GPa. Moreover, the glass-ceramics which were produced with an only heating rate, presented values around 7.1 +/- 0.2 GPa, very close to those observed in the base glass.

Effects of laparoscopy on the cardiorespiratory system of brown brocket deer (Mazama gouazoubira) anesthetized with ketamine/ xylazine/ midazolam combination and isoflurane

A laparoscopia ainda é pouco utilizada como ferramenta para técnicas de reprodução assistida em cervídeos sul-americanos, não havendo informações sobre seus efeitos e protocolos anestésicos seguros para sua realização. Objetivaramse avaliar as possíveis alterações na freqüência cardíaca (FC), respiratória (FR), saturação de oxihemoglobina (SpO2) e temperatura retal (TR) durante a laparoscopia para visualização dos órgãos reprodutivos de seis fêmeas de veado-catingueiro (Mazama gouazoubira) anestesiadas com a associação cetamina (5mg/kg), xilazina (0,3mg/kg), midazolam (0,5mg/kg) e isofluorano. Cada animal, após anestesiado, foi posicionado em decúbito dorsal para realização de duas laparoscopias com insuflação abdominal de CO2 (14,2 ± 2,39mmHg; M ± EPM) com intervalo de 40 dias. Para avaliar os principais eventos da laparoscopia, esta foi dividida em três períodos: animal sem insuflação abdominal (P1), com insuflação abdominal (P2) e insuflação abdominal com os quadris elevados a 45º (P3). O controle foi realizado após 40 dias da última laparoscopia, para isto, cada animal foi novamente anestesiado e mantido em decúbito dorsal por um período de tempo igual ao tempo médio de duração das anestesias realizadas nas laparoscopias, sem que o procedimento laparoscópico fosse realizado. O tempo de anestesia dos controles foi também dividido em P1, P2 e P3, respeitando o tempo médio de duração de cada um destes períodos das laparoscopias. Para análise dos dados foi usado o teste de análise de variância (ANOVA) seguido do teste de Tukey e valores de P<0,05 considerados significativos. Não houve diferença significativa nos parâmetros estudados em nenhum dos períodos estabelecidos para o controle e laparoscopia. Porém, a FR média entre P1 (38,8 ± 4,42) e P3 (32,7 ± 4,81) e a TR média entre P1 (38,2ºC ± 0,17), P2 (37,6ºC ± 0,19) e P3 (37,0ºC ± 0,21) variaram significativamente, independente da laparoscopia. Tais dados permitiram concluir que a laparoscopia não promoveu alterações significativas nos parâmetros avaliados, embora o protocolo anestésico utilizado tenha contribuído para redução da temperatura retal resultando em risco de hipotermia durante a anestesia.