The occurrence of riddled basins and blowout bifurcations in a parametric nonlinear system

In this paper, a two parameters family $F_{\beta_1,\beta_2}$ of maps of the plane living two different subspaces invariant is studied. We observe that, our model exhibits two chaotic attractors $A_i$, $i=0,1$, lying in these invariant subspaces and identify the parameters at which $A_i$ has a locally riddled basin of attraction or becomes a chaotic saddle. Then, the occurrence of riddled basin in the global sense is investigated in an open region of $\beta_1\beta_2$-plane. We semi-conjugate our system to a random walk model and define a fractal boundary which separates the basins of attraction of the two chaotic attractors, then we describe riddled basin in detail. We show that the model undergos a sequence of bifurcations: "a blowout bifurcation", "a bifurcation to normal repulsion" and "a bifurcation by creating a new chaotic attractor with an intermingled basin". Numerical simulations are presented graphically to confirm the validity of our results.Comment: 26 pages, 15 figure

Interleukin 6, interleukin 1&#946, estradiol and testosterone concentrations in serum and follicular fluid of females with stimulated and non-stimulated ovaries

The ovarian physiology is regulated by some complex factors such as hormones and growth factors. The hormones and growth factors are synthesized by follicular and ovarian cells during follicular maturation stage and cytokines are synthesized by the immune system. Interaction between immune and endocrine systems modulates ovarian function through the secretion of regulatory soluble factors, especially cytokines. There is a close contact between corona-cumulus-oocyte complex with follicular fluid which affects the quality and degree of oocyte maturation. The objectives of this study were to determine the levels of interleukin-6 (IL-6), interleukin 1β, estradiol and testosterone concentration in serum and follicular fluid of women with stimulated and non-stimulated ovaries. A total of 41 women, 27 in stimulated and 14 non-stimulated cycles, undergoing intra cytoplasmic sperm injection (ICSI) treatment were included in this study. Follicular fluid and serum samples from all cases were collected at the time of oocyte retrieval and concentration of testosterone, estradiol, interleukin 6 and interleukin 1β were measured. The results show that serum concentration of testosterone was significantly higher in non stimulated cases. Also, the serum and follicular fluid concentrations of interleukin 6 and interleukin 1β in stimulated cases were significantly higher than non stimulated group. There was an important negative correlation between the level of testosterone in patient's serum and IL-6 and IL-1β levels of follicular fluid. In conclusion, according to these results, it seems that the levels of testosterone and IL-6 and IL-1β in patient's serum and follicular fluid are a good factor for prediction of maturity of oocytes.Key words: Oocyte maturation, follicular fluid, interleukin 6, interleukin 1β, testosterone, estradiol

Design and analysis of porous functionally graded femoral prostheses with improved stress shielding

One of the most important problems of total hip replacement is aseptic loosening of the femoral component, which is related to the changes of the stress distribution pattern after implantation of the prosthesis. Stress shielding of the femur is recognized as a primary factor in aseptic loosening of hip replacements. Utilizing different materials is one of the ordinary solutions for that problem, but using functionally graded materials (FGMs) could be better than the conventional solutions. This research work aims at investigating different porous FGM implants and a real femoral bone by a 3D finite element method. The results show that a neutral functionally graded prosthesis cannot extraordinarily make changes in the stress pattern of bone and prosthesis, but an increasing functionally graded prosthesis leads a lower level of stress in the prosthesis, and a decreasing functionally graded prosthesis can properly reduce the stress shielding among these three architectures. Due to the absence of similar results in the specialized literature, this paper is likely to fill a gap in the state-of-the-art bio-implants, and provide pertinent results that are instrumental in the design of porous femoral prostheses under normal walking loading conditions

The Pragmatic Instruction Effects on Persian EFL Learners’ Noticing and Learning Outcomes in Request Forms

This study investigates the request strategies used by Persian learners of English as a Foreign Language (EFL), aimed at exploring the pragmatic instruction effects on their noticing constrained by different types of treatment tasks. The subsequent effect of the learners’ noticing on their learning outcomes is taken into account as well. Thirty learners were divided into two instructional (treatment) conditions: a form-comparison condition and a form-search condition. Discourse completion tests were used to generate data related to the request strategies used by each group in pre- and posttests. The treatment data were examined regarding the extent to which the learners had noticed the appropriate manner of request realization in English and were further compared with the posttest. The findings revealed that during the treatment, the amount of learners’ noticing the target request forms in the form-comparison condition was greater than the form-search condition. Furthermore, learners’ higher awareness of the target request forms in the form-comparison condition could lead them to have a better performance in their posttest