Publish in OALib Journal
APC: Only $99
This study examined the effect of underground
water on reproduction- and growth-related hormones in blue gourami
males under non-reproductive and reproductive conditions. An increase in the
percentage of males building nests under the highest percentage of underground
water were compared to fish that maintained a lower percentage of underground water
in the first two days. The % Gonado-somatic index (GSI) of males building nests
was higher than non- reproductively active males in water containing the lowest
concentration of underground water. In non- reproductively active males, brain
gonadotropin releasing hormone 1 (GnRH1) and pituitary β subunit of gonadotropins (GtHs) and prolactin (PRL) mRNA levels
were significantly higher in males maintained in underground water. In
reproductively active males, mRNA levels of brain GnRH1, gonadotropin releasing
hormone 3 (GnRH3) and pituitary PRL mRNA levels were significantly higher than
males maintained in underground water. Thus, it is suggested that underground
water with high salinity and conductivity levels affects the gene expression
of repro- duction-related hormones; in reproductively active males, it
shortened the duration of nest-building by blue gourami males.
In this paper, a model is proposed to study the impact of awareness on the dynamics of dengue. It is assumed that due to awareness of the disease some susceptible take necessary precautionary measures to protect themselves from mosquito bite. A threshold is obtained for the stability of the disease-free equilibrium state. The awareness is found to affect the threshold. For the sufficiently large awareness rate, the endemic state does not exist and disease-free state remains globally stable. It is concluded that the increase in the awareness rate decreases the densities of infectious populations of human as well as mosquitoes.
Reproduction is among basic functions of living beings and one of elementary complex subjects of the biology course. This is complicated for learners to construct cognitive structures on the subject. The aim of the current study is to investigate pre-service biology teachers’ cognitive structures related to “reproduction” through the free word-association test and the drawing-writing technique. As the research design of the study, the qualitative research method was applied. The data were collected from pre-service biology teachers. The free word-association test and the drawing-writing technique were used as data collection instruments. The data were subject to content analysis and divided into categories through coding. With the help of these categories, the cognitive structures of pre-service biology teachers were explained. The data collected through the study were divided into 7 categories (structures required for reproduction, re-production in plants and sections, types of reproduction, insemination, reproduction-inheritance, defining reproduction and its importance, reproductive anatomy). In the categories obtained, it was determined that ample data could be collected using different assessment instruments. On the other hand, it was de- termined that pre-service biology teachers had alternative conceptions related to reproduction. It was observed that the pre-service teachers had imperfect cognitive structures regarding the subject of reproduction. Comprehensive suggestions related to the subject are presented at the end of this article.