KINEMATIC ANALYSIS OF GOLF SWING PERFORMED WITH INTENDED LATE HITTING

The purposes of this study were to analyze and compare the kinematic parameters for standard and purpose golf swings. The purpose golf swing is characterized as intended late hitting and increase displacement of ball through the air (carry). Twenty-five male college golfers were recruited as sUbjects and Science eye field 3 camera system was used to measure the parameters of deterministic model. Paired t-test was used to compare between two different golf swings and correlation coefficients between selected parameters and carry were also computed. As results, a significant difference between standard and purpose golf swings was found in terms of increasing carry. Coefficients of correlation indicated that post-impact ball velocity, pre-impact club head velocity, and meet rate were positively correlated with carry. However, backspin, and angle of release were negatively correlated with carry. These results represented that the parameters of deterministic model were very useful indicators to determine performance and the purpose swing is beneficial to increase carry

Some Aspects of -Units in BCK-Algebras

We explore properties of the set of d-units of a -algebra. A property of interest in the study of -units in -algebras is the weak associative property. It is noted that many other -algebras, especially -algebras, are in fact weakly associative. The existence of -algebras which are not weakly associative is demonstrated. Moreover, the notions of a -integral domain and a left-injectivity are discussed

Radical Structures of Fuzzy Polynomial Ideals in a Ring

We investigate the radical structure of a fuzzy polynomial ideal induced by a fuzzy ideal of a ring and study its properties. Given a fuzzy ideal β of R and a homomorphism f:R→R′, we show that if fx is the induced homomorphism of f, that is, fx(∑i=0naixi)=∑i=0nf(ai)xi, then fx-1[(β)x]=(f-1(β))x

Normal stress difference-driven particle focusing in nanoparticle colloidal dispersion

Colloidal dispersion has elastic properties due to Brownian relaxation process. However, experimental evidence for the elastic properties, characterized with normal stress differences, is elusive in shearing colloidal dispersion, particularly at low Peclet numbers (Pe < 1). Here, we report that single micrometer-sized polystyrene (PS) beads, suspended in silica nanoparticle dispersion (8 nm radius; 22%, v/v), laterally migrate and form a tightly focused stream by the normal stress differences, generated in pressure-driven microtube flow at low Pe. The nanoparticle dispersion was expected to behave as a Newtonian fluid because of its ultrashort relaxation time (2 mu s), but large shear strain experienced by the PS beads causes the notable non-Newtonian behavior. We demonstrate that the unique rheological properties of the nanoparticle dispersion generate the secondary flow in perpendicular to mainstream in a noncircular conduit, and the elastic properties of blood plasma-constituting protein solutions are elucidated by the colloidal dynamics of protein molecules

TIBIO-FEMORAL JOINT FORCES DURING THE LANDING PHASE OF DIFFERENT TYPES OF VERTICAL JUMP

The purpose of this study was to compare the tibio-femoral contact forces during the landing phases of 8 different types of vertical jump (squat, countermovement, hop approach and drop jumps each with and without the use of arms). Data were collected from eight males and eight females. Two S-VHS camcorders and a force platform were used to obtain the 3-D kinematics and kinetics of the knee joint. Activities of selected muscles spanning the knee joint were monitored using surface electromyographic (EMG) techniques. The EMG-assisted optimization model was used to estimate the tibio-femoral joint forces. The peak compressive contact forces ranged from 3-5 body weight (SW) and from 2.5-3.7 SW for the males and females, respectively. These loads seldom fell within the range that is considered to be damaging to the cartilage at the knee

THE EFFECTS OF WEARING ROLLER SHOES ON GROUND REACTION FORCE CHARACTERISTICS DURING WALKING

Roller shoes have become increasingly popular among children and it features retractable wheels which allowing the user to walk or roll without changing the footwear. Maintaining balance during forward walking with roller shoes is not an easy task. To prevent falling backward, the user needs to lock the knees and tighten the ankles and thighs while the upper body is slightly leaning forward. Constant walking with roller shoes forces the user to walk in a manner much different from normal gait. Prolonged exposure to un-natural stresses on human body forces our body to evolve by strengthening those incorrect, and temporary functions (Clement et aI., 1981). For children, the chronic stress may lead to serious injuries in the lower extremity later in life. If any potential' of injury exists in a movement it is critical to examine the associated forces that may lead to injury. To the best of our knowledge, the effects of wearing roller shoes on ground reaction forces (GRF) characteristics have rarely been studied, especially in the youth population. Thus, the purpose of this study was to compare GRF characteristics during walking wearing jogging and roller shoes

Phytohormone abscisic acid control RNA-dependent RNA polymerase 6 gene expression and post-transcriptional gene silencing in rice cells

RNA-dependent RNA polymerase 6 (RDR6) catalyses dsRNA synthesis for post-transcriptional gene silencing (PTGS)-associated amplification and the generation of endogeneous siRNAs involved in developmental determinations or stress responses. The functional importance of RDR6 in PTGS led us to examine its connection to the cellular regulatory network by analyzing the hormonal responses of RDR6 gene expression in a cultured cell system. Delivery of dsRNA, prepared in vitro, into cultured rice (Oryza sativa cv. Japonica Dongjin) cells successfully silenced the target isocitrate lyase (ICL) transcripts. Silencing was transient in the absence of abscisic acid (ABA), while it became persistent in the presence of ABA in growth medium. A transcription assay of the OsRDR6 promoter showed that it was positively regulated by ABA. OsRDR6-dependent siRNA(ICL) generation was also significantly up-regulated by ABA. The results showed that, among the five rice OsRDR isogenes, only OsRDR6 was responsible for the observed ABA-mediated amplification and silencing of ICL transcripts. We propose that ABA modulates PTGS through the transcriptional control of the OsRDR6 gene