Fat tail phenomena in a stochastic model of stock market : the long-range percolation approach

Using a Gibbs distribution developed in the theory of statistical physics and a long−range percolation theory, we present a new model of a stock price process for explaining the fat tail in the distribution of stock returns. We consider two types of traders, Group A and Group B : Group A traders analyze the past data on the stock market to determine their present trading positions. The way to determine their trading positions is not deterministic but obeys a Gibbs distribution with interactions between the past data and the present trading positions. On the other hand, Group B traders follow the advice reached through the long−range percolation system from the investment adviser. As the resulting stock price process, we derive a Lévy process

New ductile fracture criterion for prediction of internal fracture in skew rolling

Skew rolling is the process of reducing the diameter of a round billet. In this process, internal fracture may occur in the rolled material. This phenomenon is known as the Mannesmann effect. While there has been great discussion about the mechanism of internal fracture, it has yet to be fully clarified. To investigate the internal fracture initiation and propagation, we conducted hot rolling experiments and evaluated the stress and strain of the rolled material by elasto-plastic finite element analysis. The results show that the internal fracture arises on the internal surface in which shear stress acts owing to the combined effect of tensile and shear stress. In this paper, a new ductile fracture criterion is discussed to quantitatively predict the occurrence of internal fracture in skew rolling

Preference by Adult Female Riptortus Clavatus Thunberg for Plants from the Fabaceae and Other Plant Families

To obtain basic knowledge regarding the preference of adult female Riptortus clavatus for particular host plants, we investigated the preference of R. clavatus for green soybean, common bean, and cow pea as host plants, and between cow pea and either bell pepper, lettuce, cabbage, or cucumber. R. clavatus indicated a preference for cow pea over green soybean, followed by common bean. In addition, it was indicated that R. clavatus can distinguish among host plants. R. clavatus preferred cow pea over various non-host plants to a highly significant degree. These results clarified that adult female R. clavatus have strong ability to distinguish among host and non-host plants in the Fabaceae

Hydrophobic Silicone Elastomer Chamber for Recording Trajectories of Motile Porcine Sperms without Adsorption

Motile porcine sperms adhere to hydrophilic materials such as glass and plastics. The adsorption of sperms to a hydrophobic poly(dimethylsiloxane) (PDMS) membrane is less compared with that to glass. We investigated the linear velocity (LV) and amplitude of lateral head displacement (ALHD) of motile porcine sperm on glass and PDMS preparations using computer-assisted sperm analysis (CASA). Significant decreases were observed in the 15-min LV (P<0.05) and ALHD (P<0.05) in motile porcine sperm on glass preparations compared with those on PDMS preparations. These differences were due to adsorption of the head and/or neck to hydrophilic substrates. Because of the elasticity of PDMS, we propose that a PDMS membrane should be used for CASA. To investigate the dynamics of motile porcine sperms with microfluidics, we do not recommend plasma treatment to bond PDMS and glass in the microchannel preparation; instead, we suggest that a PDMS molding process without plasma treatment be used for preparation of microfluidic channels

High Subsidence Rate After Primary Total Hip Arthroplasty Using a Zweymüller-type Noncemented Implant With a Matte Surface

INTRODUCTION: The surface topography is one key factor that affects the initial fixation of prosthesis in total hip arthroplasty (THA). We aimed to evaluate the mid-term results of a Zweymüller-type noncemented femoral implant (Elance stem) that had a matte surface with a target average roughness of 1.0 to 2.5 μm. The prosthesis was subjected to alkali and heat treatments to enhance its bone-bonding property. METHODS: In this retrospective study, 30 THAs (27 patients) done using an Elance stem from September 2012 to October 2014 were evaluated clinically and radiographically for a mean follow-up of 6.3 ± 1.7 years after the index THA. RESULTS: Stem revision was indicated for six hips (20%). The survival rate with stem revision for any reason was 86.4% (95% confidence interval, 68.9%-94.8%) at 5 years. Stem subsidence >5 mm was noted in 17 hips (56.7%). The survival rate with stem subsidence >5 mm as the end point was 46.6% (95% confidence interval, 29.9%-64.2%) at 5 years. CONCLUSION: The Zweymüller-type noncemented stem with a low-roughness matte surface demonstrated a high subsidence rate, although the bone-bonding property was potentially enhanced by the alkali and heat treatments. Surgeons should be aware that an insufficient surface roughness could lead to poor mechanical fixation of the noncemented stem, even with an appropriate stem geometry and surface chemistry

Brachial Artery Dissection Caused by Closed Elbow Dislocation in a Snowboarder: A Case Report and Review of Literature

This report describes a rare case of brachial artery dissection associated with closed elbow dislocation caused by a snowboarding injury. After peripheral ischaemic findings in the right upper extremity were confirmed, urgent duplex-sonography was performed to diagnose the brachial artery injury. Urgent revascularisation surgery was promptly performed, and arterial dissection was diagnosed by intraoperative findings, in which the adventitia of the brachial artery was intact and the intima was disrupted. In this case, because there was no golden time window before undertaking urgent revascularisation surgery, duplex-sonography was very useful for making an emergency diagnosis. To diagnose arterial dissection, because the adventitia of the brachial artery is intact, it is necessary to perform arteriotomy to identify intimal disruption in the brachial artery. When diagnosing traumatic elbow dislocation, it is important to suspect arterial dissection

Difference in Therapeutic Strategies for Joint‐Preserving Surgery for Non‐Traumatic Osteonecrosis of the Femoral Head between the United States and Japan: A Review of the Literature

For patients with non-traumatic osteonecrosis of the femoral head (ONFH), core decompression (CD) and bone grafts (BG) are mainly performed in the West, while osteotomy is found to be predominant in Japan. It is not well recognized how the surgical procedures for joint preservation in patients with ONFH are completely different between the United States and Japan. This paper identifies the contexts and the differences in treatment strategies for ONFH between the two countries. We compared the surgical trends of the two countries over three periods, 1997-2001, 2002-2006, and 2007-2011 (the US data for the third period was 2007-2008), based on a 2014 US paper and a 2013 national publication in Japan. We compared the details of surgery for non-traumatic ONFH under the same conditions in the two reports. For the period 1997-2001, the rates of surgeries for ONFH in the US were as follows: total hip arthroplasty (THA), 86%; CD, 10%; and osteotomy, 0.4%. In Japan, THA was 61%, osteotomy 38%, and CD 0%. For the recent period, 2007-2011 (US 2007-2008), the rate of THA was 91%, CD 6%, and osteotomy 0.1%, in the US, compared to a THA rate of 73%, CD 0%, and osteotomy 26% in Japan. The results for the interim period (2002-2006) were between the old and new data. The use of joint-preserving surgery for ONFH differs greatly between the US and Japan. The first-line joint-preserving surgery was CD in the US and osteotomy in Japan. Each procedure was rarely done in the other country. From about 2000 to 2010, the percentage of THA increased in both countries. The proportion of joint-preserving surgery (CD in the US and osteotomy in Japan) declined. The decrease in joint-preserving procedures may be largely attributed to improved long-term outcomes of THA due to technological advances. There is also a reluctance for young ONFH patients to undergo joint-preserving procedures, such as osteotomy, that require long-term hospitalization