430 research outputs found

    An Optimal Weight for Realized Variance Based on Intermittent High-Frequency Data

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    In Japanese stock markets, there are two kinds of breaks, i.e., nighttime and lunch break, where we have no trading, entailing inevitable increase of variance in estimating daily volatility via naive realized variance (RV). In order to perform a much more stabilized estimation, we are concerned here with a modification of the weighting technique of Hansen and Lunde (2005). As an empirical study, we estimate optimal weights in a certain sense for Japanese stock data listed on the Tokyo Stock Exchange. We found that, in most stocks appropriate use of the optimally weighted RV can lead to remarkably smaller estimation variance compared with naive RV, hence substantially to more accurate forecasting of daily volatility.high-frequency data, market microstructure noise, realized volatility, Japanese stock markets, variance of realized variance

    Rice Coleoptile Growth under Water and in Air-Possible Effect of Buoyancy on Growth and Cell Walls

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    Maximum growth was achieved in rice coleoptiles (Oryza sativa L. cv. Sasanishiki) grown under water; they reached maximum length of 81.2 mm on day 5. The maximum length of coleoptiles grown in air or under water with air bubbling was 12.4 mm and 23.5 mm in day 5,respectively. Differences in coleoptile growth between air bubbling and air conditions, namely approximately 11 mm at day 5,could be due to buoyancy effect under water. Promoted growth under water was due to a decrease in cell wall extensibility. The decrease in cell wall extensibility could be related to the inhibition of the formation of diferulic acid-bridges among arabinoxylans in cell walls under water

    THE DISTANCE COVERED OF SOCCER AND RUGBY REFEREES DURING THE MATCH USING A MOBILE "GPS"

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    The purpose of this study was to measure the distance covered of soccer and rugby referees during the match using mobile GPS method. And also, the distance covered measured by GPS method 'Nas compared with VTR method and manual tracing method, so as to examine availability of a mobile GPS. Nine soccer referees and ten rugby referees participated in this study. The distance covered was measured by mobile GPS method, VTR method and manual tracing method. In the case of soccer referee, there was no significant difference between mobile GPS method and VTR method. While the case of rugby referee, there was no significant difference among three methods. Therefore, it was concluded the mobile GPS might have the possibility of one effective instrument for measuring the referee's distance covered during soccer and rugby match

    Comparison of two simple stitches and modified Mason-Allen suture for medial meniscus posterior root tear based on the progression of meniscal posterior extrusion: A retrospective cohort study

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    Purpose: Medial meniscus (MM) posterior root (PR) tear leads to severe MM posterior extrusion (PE), resulting in rapid knee cartilage degeneration. MMPR repairs are recommended to reduce MMPE, especially during knee flexion. However, the difference in MMPE between different repair techniques remains unknown. This study aimed to investigate preoperative and postoperative MMPE following several pullout repair techniques. We hypothesized that a technique using two simple stitches (TSS) would be more useful than FasT-Fix-dependent modified Mason-Allen suture (F-MMA) to prevent the progression of MMPE in knee extension. Methods: This retrospective study included 35 patients who underwent MMPR repair. To compare MMPE, patients were divided into two groups according to the use of F-MMA while grasping the posterior capsule and TSS without grasping it. Open magnetic resonance imaging was performed at 10 degrees and 90 degrees knee flexion preoperatively, and at 3 and 12 months postoperatively, and the MMPE of both groups was evaluated. Results: A significant difference was observed between preoperative and 3-month postoperative MMPE at 90 degrees knee flexion in both groups (p Conclusions: Both repairs were found to be useful to reduce MMPE in knee flexion. Further, F-MMA repair increased MMPE in knee extension, unlike TSS repair. These findings suggest that TSS might have more advantages for load distribution when standing or walking

    Sternoclavicular joint septic arthritis following paraspinal muscle abscess and septic lumbar spondylodiscitis with epidural abscess in a patient with diabetes: a case report

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    BACKGROUND: Septic arthritis of the sternoclavicular joint (SCJ) is extremely rare, and usually appears to result from hematogenous spread. Predisposing factors include immunocompromising diseases such as diabetes. CASE PRESENTATION: A 61-year-old man with poorly controlled diabetes mellitus presented to our emergency department with low back pain, high fever, and a painful mass over his left SCJ. He had received two epidural blocks over the past 2 weeks for severe back and leg pain secondary to lumbar disc herniation. He did not complain of weakness or sensory changes of his lower limbs, and his bladder and bowel function were normal. He had no history of shoulder injection, subclavian vein catheterization, intravenous drug abuse, or focal infection including tooth decay. CT showed an abscess of the left SCJ, with extension into the mediastinum and sternocleidomastoid muscle, and left paraspinal muscle swelling at the level of L2. MRI showed spondylodiscitis of L3-L4 with a contiguous extradural abscess. Staphylococcus aureus was isolated from cultures of aspirated pus from his SCJ, and from his urine and blood. The SCJ abscess was incised and drained, and appropriate intravenous antibiotic therapy was administered. Two weeks after admission, the purulent discharge from the left SCJ had completely stopped, and the wound showed improvement. He was transferred to another ward for treatment of the ongoing back pain. CONCLUSION: Diabetic patients with S. aureus bacteremia may be at risk of severe musculoskeletal infections via hematogenous spread

    Transtibial pullout repair of the lateral meniscus posterior root tear combined with anterior cruciate ligament reconstruction reduces lateral meniscus extrusion: A retrospective study

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    Background Lateral meniscus (LM) posterior root tear (PRT) is often associated with anterior cruciate ligament (ACL) injury and can result in rotational instability, joint overloading, and degenerative changes in the knee. Improved rotational stability and kinematics have been reported after LMPRT repair. However, it is unclear what repair technique can achieve the greatest reduction in LM extrusion (LME). Hypothesis We hypothesized that transtibial pullout repair would decrease LME to a greater extent than other repair techniques. Patients and methods Seventeen patients with ACL injury and complete LMPRT were evaluated. Nine underwent ACL reconstruction (ACLR) and transtibial pullout repair, and eight underwent ACLR and other repairs such as inside-out suturing. Double-bundle ACLR was performed using hamstring tendons, and LMPRT pullout repair was performed through the bone tunnel for the posterolateral bundle. Magnetic resonance imaging was performed immediately preoperatively and at > 6 months postoperatively, and LME was measured from coronal images only. Results A significantly greater decrease in the value of LME from pre- to postoperative measurement was observed in the transtibial pullout repair group (−0.5 ± 0.7 mm) than in the other-repair group (1.0 ± 0.9 mm, p Discussion The most important finding of this study was that transtibial pullout repair resulted in a greater decrease in LME than other repair techniques in patients with ACL injury and LMPRT. This technique might be useful for restoring hoop tension by decreasing LME
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