sahar hatami

Systematic and non-systematic risks have influence on decisions in agriculture sector. Evaluating the performance of different crops in terms of returns and risk using appropriate performance indices is important. Such evaluation provides the necessary information to change crop pattern to a pattern that meets the risk conditions of each region and help to reorganize the crop production. Accordingly, this study aims to evaluate the performance of major crops in different provinces of Iran based on Portfolio Performance Evaluation Indicators and then to develop a pattern corresponding to these indicators for different major production regions of the country, using data for 2001 to 2019 period. The results of this study show that there is no proportionality between the high Sharpe ratio and the share of cultivated area in the provinces of the country, i.e. that the largest share of cultivated area in a province does not belong to the crops that have the highest Sharpe ratio. This result indicates that farmers do not act correctly in taking into account the cost of risk in choosing the crops to produce. Accordingly, changes in crop pattern and increasing the knowledge of farmers on the risk consideration is recommended.

Cryopreservation of pre-antral follicles is a hopeful technique to preserve female fertility. The aim of the present study was to evaluate reactive oxygen species (ROS) and total antioxidant capacity (TAC) levels of mouse vitrified pre-antral follicles in the presence of alpha lipoic acid (ALA). Isolated pre-antral follicles (140–150 µm in diameter) were divided into vitrified–warmed and fresh groups. Each group was subjected to in vitro maturation with or without ALA for 12 days، followed by adding human chronic gonadotropin to induce ovulation. In vitro fertilization was performed to evaluate their developmental competence. In parallel، the amount of ROS and TAC were assessed after 0، 24، 48، 72، and 96 h of culture by 2''،7''-dichlorofluorescin assay and ferric reducing/antioxidant power assay، respectively. The respective rates of survival، antrum formation، and metaphase II oocytes were significantly higher in ALA-supplemented groups compared to the groups not treated with ALA. TAC and ROS levels were significantly decreased and increased، respectively during the culture period up to 96 h in the absence of ALA in both vitrified and non-vitrified samples. However، with pretreatment of ALA، TAC levels were increased significantly and remained constant up to 96 h in vitrified-warmed pre-antral follicles، while ROS levels completely returned to the level of starting point after 96 h of culture in the presence of ALA. Pretreatment of ALA positively influences development of pre-antral follicles in vitrified and non-vitrified samples through increasing follicular TAC level and decreasing ROS levels.

The aim of this study was to evaluate the in vitro developmental competence of mouse vitrified pre-antral follicles in comparison to isolated pre-antral follicles derived from vitrified ovaries in the presence of alpha lipoic acid (ALA). Pre-antral follicles derived from fresh, vitrified-warmed ovarian tissues and vitrified–warmed pre-antral follicles were cultured individually with or without ALA, followed by adding hCG to induce ovulation. The follicle growth, oocyte maturation, and embryo development were assessed. The diameter and development of follicles, oocyte maturation and embryo development rates were significantly higher in ALA supplemented groups compared to the respective ALA-free conditions groups. Aforementioned parameters were significantly higher in vitrified-warmed follicles in comparison to follicles derived from vitrified-warmed ovaries. These findings support a superior performance of pre-antral follicles when vitrified rather than when isolated from vitrified ovaries with regard to increasing the rates of developmental parameters. Moreover, ALA improves the in vitro maturation of pre-antral follicles in vitrified and non-vitrified samples.