WATER ABSORPTION of THE FUR and SWIMMING BEHAVIOR of SEMIAQUATIC and TERRESTRIAL ORYZOMINE RODENTS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aggressive Behavior and Performance in the Tegu Lizard Tupinambis merianae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biological behavior of the gerbil ventral prostate in three phases of postnatal development

In this study, we characterized the gerbil's ventral prostate histology ultrastructurally and quantitatively throughout three phases of postnatal development (young, adult, and old) in order to comprehend its biological behavior and propensity to developing spontaneous lesions with aging. The gerbil prostate is composed of alveoli and ducts immersed in a stroma composed of smooth muscle, fibroblasts, collagen and elastic fibers and vessels. The prostate tissue components present morphological and quantitative aspects that vary according to age. Young animals have an immature gland with modest secretory activity. Synthetic activity remained stable in adult and old gerbil. However, prostatic morphology was altered in the aging, showing an increased epithelium and stromal fibrosis. The nuclei of the secretory cells increased with aging, whereas nucleoli presented few alterations during postnatal development. The epithelial proliferation and stromal remodeling noted in this study indicate that the gerbil prostate may respond to the androgen declines typical of senescence through epithelial proliferation and stromal remodeling.

Cellular and extracellular behavior in the gerbil (Meriones unguiculatus) ventral prostate following different types of castration and the consequences of testosterone replacement

Mongolian gerbils (Meriones unguiculatus) were grouped into two experimental groups: GEx.01 suffered orchiectomy and after 30 days received doses of testosterone cipionate (T), while GEx.02 received weekly and alternated doses of the anti-androgens cyproterone acetate and flutamide for 30 days, and the animals were then euthanized. Structural evaluation reveals a more intense reduction in epithelial height in GEx.02. Smooth muscle cells (SMC) presented a star-shaped aspect after 30 days of hormonal ablation and basal membrane was shown to be more intensely grooved in GEx.01. In both groups, after hormonal replacement, recovery in epithelial height could be noted and the SMC presented its phenotypes, but an increase in RER was seen, characterizing a modulation from its contractile to secreting phenotype. In conclusion, the prostate presented involution capacity after androgen ablation and the ability to reorganize after hormonal replacement, but events resulting from orchiectomy and subsequent T replacement were shown to be more aggressive to the prostate. (c) 2006 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

Reproductive behavior and seasonal occurrence of Psecas viridipurpureus (Salticidae, Araneae)

O comportamento reprodutivo e a ocorrência sazonal de Psecas viridipurpureus foram estudados na Estação Ecológica do Noroeste Paulista, uma pequena área de conservação na região noroeste do Estado de São Paulo, Brasil (49º22'50W e 20º48'36S). P. viridipurpureus ocorreu em gravatás, uma bromeliácea (Bromelia balansae, Bromeliaceae) que não acumula água de chuva. Durante a exibição de corte, o casal ocupou a região mediana das folhas de gravatás, com o macho sempre localizado em uma posição superior à da fêmea. Os machos de P. viridipurpureus apresentaram um comportamento de corte complexo, que incluiu cinco padrões motores. O comportamento de corte e a cópula ocorreram preponderantemente durante a estação chuvosa e o recrutamento de jovens entre dezembro e julho. O abrigo de P. viridipurpureus difere do padrão de Salticidae, pois as ootecas são recobertas por uma cobertura de seda plana e não são incluídas em casulos.

Burrowing behavior of Dermatonotus muelleri (Anura, Microhylidae) with reference to the origin of the burrowing behavior of Anura

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Social isolation and aggressiveness in the Amazonian juvenile fish Astronotus ocellatus

Testamos o efeito do isolamento social sobre a agressividade no peixe amazônico, Astronotus ocellatus. Dez peixes juvenis foram transferidos de um aquário de agrupamento (60 x 60 x 40 cm) contendo 15 indivíduos (sem discriminação de sexo) para um aquário de isolamento (50 x 40 x 40 cm). A agressividade foi testada por meio de ataques e exibições direcionadas à imagem do peixe no espelho. O comportamento foi filmado durante 10 min em 4 momentos: 30 min, 1 dia, 5 dias e 15 dias após o isolamento. Nós analisamos a motivação agressiva por meio da latência para início do comportamento agonístico e pela freqüência dos ataques totais e específicos direcionados ao espelho. A latência para o comportamento agonístico reduziu ao longo do isolamento e houve uma tendência de aumento da freqüência de mouth fighting (um ataque de alta intensidade de agressão), mostrando-nos um aumento na motivação agressiva. Os resultados estão de acordo com os encontrados para ciclídeos juvenís de Haplochromis burtoni, mas discordam com os encontrados para Pterophylum scalare (acará bandeira). Sugerimos que o aumento da agressividade em A. ocellatus pode ser mediado pelo efeito de exposição prévia, da residência prévia ou por processos envolvendo reconhecimento de co-específicos.

Relaxor behavior in multiferroic BiMn2O5 ceramics

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

Comparative electrical behavior at low and high current of SnO(2)- and ZnO-based varistors

The complete I-V characteristics of SnO(2)-based varistors, particularly of the Pianaro system SCNCr consisting in 98.9%SnO(2)+1%CoO+0.05%Nb(2)O(5)+0.05%Cr(2)O(3), all in mol%, have been seldom reported in the literature. A comparative study at low and high currents of the nonohmic behavior of SCNCr- and ZnO-based varistors (modified Matsuoka system) is proposed in this work. The SCNCr system showed higher nonlinearity coefficients in the whole range of measured current. The electrical breakdown field (E(b)) was twice as high for the SCNCr system (5400 V/cm) than for the ZnO varistor (2600 V/cm) due to a smaller average grain size of the former (4.5 mu m) with respect to the latter (8.5 mu m). Nevertheless, we consider that another important factor responsible for the high E(b) in the SCNCr system is the great number of electrically active interfaces (85%) as determined with electrostatic force microscopy (EFM). It was also established that the SCNCr system might be produced in disks of smaller dimensions than that of commercial ZnO-based product, with a 5.0 cm(-1) minimal area-volume (A/V) ratio. The SCNCr reached the saturation current in a short time because of the high resistivity of the grains, which is five times higher than that of the grains in ZnO-based varistors.

Tolerance to the air exposition test of Hoplias lacerdae larvae and juvenile during its initial development

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relationship between temporomandibular disorders and orthodontic treatment: a literature review

OBJETIVO: revisar a literatura mais atual, dos últimos 15 anos, em busca de estudos clínicos que relatem a relação entre a disfunção temporomandibular (DTM) e o tratamento ortodôntico e/ou a má oclusão. A intenção foi verificar se o tratamento ortodôntico aumentaria o aparecimento de sinais e sintomas de DTM, e se o tratamento ortodôntico seria um recurso para o tratamento ou prevenção dos sinais e sintomas de DTM. MÉTODOS: artigos dos tipos revisão de literatura, editorial, carta, estudo experimental em animais e comunicação foram excluídos dessa revisão. Foram incluídos artigos prospectivos, longitudinais, caso-controle ou retrospectivo com amostra maior, com relevante análise estatística. Estudos que abordassem deformidades e síndromes craniofaciais e tratamento por cirurgia ortognática também foram excluídos, bem como aqueles que relatassem apenas a associação entre má oclusão e DTM. RESULTADOS: foram encontrados 20 artigos relacionando Ortodontia à DTM, segundo os critérios adotados. Os estudos, então, associando sinais e sintomas de DTM ao tratamento ortodôntico apresentaram resultados heterogêneos. Alguns encontraram efeitos positivos do tratamento ortodôntico para os sinais e sintomas de DTM; entretanto, nenhum deles apresentou diferença estatisticamente significativa. CONCLUSÕES: todos os estudos citados nessa revisão de literatura relataram que o tratamento ortodôntico não forneceu risco ao desenvolvimento de sinais e sintomas de DTM, independentemente da técnica utilizada para tratamento, da exodontia ou não de pré-molares e do tipo de má oclusão previamente apresentada pelo paciente. Alguns estudos realizados com acompanhamento em longo prazo concluíram que o tratamento ortodôntico não seria preventivo ou uma modalidade de tratamento para DTM.

Sexual behavior and fertility of male rats submitted to prolonged immobilization-induced stress

In order to investigate whether prolonged stress interferes with the onset of sexual behavior at puberty and with fertility at adulthood, prepubertal male Wistar rats (40 days of age) were immobilized 6 h a day for 15 days (up to early puberty) or for 60 days (until sexual maturity). Pubertal stressed rats showed a two-fold increase in the latency for the first mount (probably due to repeated aversive experience in which a change of environment was always followed by immobilization) and a 2.5-fold increase in the frequency of thrusting (indicative of enhanced sexual performance). The apparently stimulatory effect of prolonged stress on the onset of sexual behavior is discussed in terms of increased testosterone level and interference with the complex interchanges between the neurotransmitters/neuropeptides involved in the central control of male sexual activity. Adult stressed animals were mated with normal females, which became pregnant but exhibited a more than two-fold increase in both pre-implantation and post-implantation loss, probably due to a smaller rate of fertilization and/or fertilization with damaged spermatozoa.

Behavior of an albino vampire bat, Desmodus rotundus (E. Geoffroy) (Chiroptera, Phyllostomidae), in captivity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ingestive behavior and performance of female lambs grazing on Marandu palisadegrass under different stocking rates

The ingestive behavior and performance of female lambs grazing on Marandu pasture submitted to different stocking rates during the rainy and transition season were evaluated. The experimental area with 4,500 m² was divided into 45 paddocks of 100 m². Twenty-seven Santa Ines female lambs (purebred) with 4 months age and 22 kg of initial body weight were distributed in a completely randomized design, with nine replicates. Lambs were divided into 9 groups with the same initial weight and submitted to three stocking rates: 2, 3 and 4 lambs/paddock, which corresponded to 40, 60 and 80 lambs/ha, respectively. Each group of animals had a module of five paddocks, managed on intermittent grazing system, with 7 days of occupation and 28 d of rest. Increase on time grazing and reduction on time ruminating and resting were observed as stocking rates increased. There was 14% raise in time grazing and 41% decline on time resting by lambs subjected to the highest stocking rate compared with those in the lower stocking rate. The number of animals/ha promoted linear effect on average daily gain, which was higher for animals in the lowest stocking rate of 90 g/d. For gain per area, the best result was obtained with 60 animals/ha featuring an average value of 426 kg/ha.

Influence of age on the behavior of dental pulp of dog teeth after capping with an adhesive system or calcium hydroxide

This study evaluated histomorphologically the influence of chronological age of the dog on the dental pulp-healing process after capping with the All Bond 2 system or with calcium hydroxide paste. The animals were divided according to age into young and adult groups. Class 5-type cavities were prepared, and the pulp was submitted to an exposure of a diameter of 0.5 mm. The pulp of the teeth was then protected with the adhesive system or with a calcium hydroxide paste. Sixty days after treatment, the results obtained with the adhesive system in the young group were significantly better than those in the adult group. With calcium hydroxide, the results were similar for both groups. The pulp treated with calcium hydroxide exhibited a complete hard tissue bridge and a pulp without inflammatory reaction, a fact not observed when the adhesive system was used. In conclusion, the chronological age of the pulp influenced the comparative results only for the adhesive system (P = 0.1), and the total results were better with calcium hydroxide than with the All Bond 2 system (P = 0.01).