MAPPING THE LINKS BETWEEN STARS, GAS, AND DARK MATTER WITH LARGE SURVEYS

The evolution of galaxies is driven by complex interplay between multiple components of the Universe, including stars, gas, and dark matter. To advance our understanding of galaxy evolution, it is essential to characterize the interactions between these components. This dissertation explicates the applications of statistical techniques for extracting new information from large survey data in order to investigate the relationships between stars, gas and dark matter. By employing the cross-correlation technique which is developed to extract relevant signals in spectroscopic and photometric datasets, I study the connections between galaxies and dark matter halos. I characterize the galaxy luminosity functions in halos with different masses. This new observation uncovers an ubiquitous upturn at the faint-end of the luminosity functions, suggesting that it is formation that regulate the stellar mass of satellite galaxies. With a simple model, I show that the shape of the luminosity functions can be used to infer the formation history of galaxies. Applying the same technique, I study the relationships between galaxies and gas around them, the circumgalactic medium. I robustly characterize the spatial distribution of gas and reveal that the cool gas around star-forming galaxies and those around passive galaxies exhibit different behaviors. This result demonstrates that the dichotomy of galaxy types is reflected in the circumgalactic medium. Finally, I explore the diffuse interstellar bands, a set of mysterious absorption lines ubiquitously seen in the interstellar medium of our Milky Way. I map the distribution of 20 different DIBs across the sky by using about half a million of SDSS spectra of quasars, galaxies, and stars. Using the map, I show that the DIB carriers have different sensitivity to the physical conditions in the ISM. The results of the dissertation demonstrate that combining large survey data and statistical techniques is a powerful and promising approach to study galaxy formation and evolution. Pursuing this direction, one can uncover new astronomical phenomena and make great progress in our understanding of galaxy formation and evolution

MUSCLE ACTIVATION AND THREE-DIMENSIONAL KINEMATICS OF UPPER EXTREMITY IN SNATCH WEIGHT LIFTING

INTRODUCTION: Previously, there was little weightlifting research focused on biomechanics of the elbow and the shoulder joints (Bartonietz, 1996). Therefore, the purposes of this study were to evaluate the kinematics of upper extremity on sagittal plane during 1st pull, transition from the 1st to the 2nd pull, 2nd pull, turnover under the barbell, catch phase, and rising from the squat position phases of snatch weight lifting and to examine upper-limb muscles activity during snatch weight lifting. The EMG signals were analyzed using the normalized linear envelopes

THE EFFECT OF MACH DRILLS TRAINING ON THE START MOVEMENT OF IN-LINE SPEED SKATING

The purpose of this study was to analyze the relative muscle activation of the start movement and the Mach Drills training program. 5 in-line skating players participated in the study and 9 Wireless EMG sensors were placed over the rectus femoris, biceps femoris, semitendinosus, tibialis anterior, gastrocnemius, peroneus longus, adductor magnus, tensor fascia lata, and gluteus maximus. Results showed that significantly lower gastrocnemius IEMG value in skating. However, it also showed that RF, TA, and PL had higher IEMG value in skating and significant difference was found for TA. Another muscle activation didn’t have significantly difference. It suggested that athletes had to increase more specific training program for rectus femoris muscle and peroneus longus muscle which play an important roles for start movement in skating