Sperm Transport Through the Female Reproductive Tract

Mammalian spermatozoa are highly complex specialized cells that survive a long and fascinating journey from the site of insemination to the upper third of the oviduct, where fertilization occurs. During this journey, these cells have to go through different microenvironments, which provide appropriate conditions for the occurrence of sperm capacitation and acrosome reaction (AR) in the time and place needed. These events need to occur in an extremely synchronized sequence in order to assure that fertilization takes place. The objective of this review article is to describe and analyze the various changes that spermatozoa will experience during their journey through the female genital tract and how they are influenced by the epithelium and secretions present in the cervix, endometrium and oviduct. These microenvironments will prevent the AR from occurring ahead of time as in the case of estrogenic cervical mucus or will stimulate its occurrence as in the case of progesterone, present during ovulation in oviductal fluid. In all cases the female reproductive tract will supply the conditions needed to guarantee survival, capacitation, AR and migration of spermatozoa for subsequent fusion with the oocyte. These microenvironments contain various hormones, neurotransmitters and other metabolites for which spermatozoa have specific receptors through which these substances can modulate their fertilizing potential. The study and understanding of the physiological conditions needed for gamete membrane fusion to occur is an important aspect to be considered both in basic and applied research in reproductive biology.

Fault Discrimination Using Synchronized Sequence Measurements under Strong White Gaussian Noise Background

In this paper on strong white Gaussian noise background based on discriminant analysis theory, we mainly adopt synchronized sequence measurements of PMU to search for laws of electrical quantities marked changes. We have developed a method to quickly and accurately discriminate fault components and fault sections. The research has shown that the fault discrimination by discriminant analysis theory is effective and reliable. Under the interference of strong random white Gaussian noise, discriminant analysis still has high redundancy.

Symbolic Computation for DS-CDMA Code Acquisition Using First Order Logic

Code division multiple access (CDMA) is widely used because of its effectiveness to send multiple signal and confidentiality of career signal. We present a formulation of state-space problem of which solution is directed by redundant reasoning control method for semiheuristic and lightweight DS-CDMA code acquisition. The reasoning of the state-space problem provides us with the way to find a K bit synchronized sequence among K dephased sequences with less calculation cost, compared with serial search and matched filter. In this process, redundancy-restriction method, called weighting strategy, enhances the searching ability of FOL (first order logic) reasoning for the faster and lightweight code acquisition. The combination of weighting strategy and correlator enables us to achieve the peak-detection within K/3 times of calculating inner products and its measurement. Our system is evaluated by the reduced cost of proving state-space problem using weighting strategy and its robustness of using the proposal code acquisition framework. Experiment shows that the proposal method is robust if K/N sequences are grouped with N ranging from 3 to 5.