Solvable Potentials from Supersymmetric Quantum Mechanics

A recurrence relation of Riccati-type differential equations known in supersymmetric quantum mechanics is investigated to find exactly solvable potentials. Taking some simple {\it ans\"atze}, we find new classes of solvable potentials as well as reproducing the known shape-invariant ones.Comment: 14 pages, Late

A simple iterative independent component analysis algorithm for vibration source signal identification of complex structures

ABSTRACT:Independent Component Analysis (ICA), one of the blind source separation methods, can be applied for extracting unknown source signals only from received signals. This is accomplished by finding statistical independence of signal mixtures and has been successfully applied to myriad fields such as medical science, image processing, and numerous others. Nevertheless, there are inherent problems that have been reported when using this technique: insta- bility and invalid ordering of separated signals, particularly when using a conventional ICA technique in vibratory source signal identification of complex structures. In this study, a simple iterative algorithm of the conventional ICA has been proposed to mitigate these problems. The proposed method to extract more stable source signals having valid order includes an iterative and reordering process of extracted mixing matrix to reconstruct finally converged source signals, referring to the magnitudes of correlation coefficients between the intermediately separated signals and the signals measured on or nearby sources. In order to review the problems of the conventional ICA technique and to vali- date the proposed method, numerical analyses have been carried out for a virtual response model and a 30m class submarine model. Moreover, in order to investigate applicability of the proposed method to real problem of complex structure, an experiment has been carried out for a scaled submarine mockup. The results show that the proposed method could resolve the inherent problems of a conventional ICA technique

The economic explainability of machine learning and standard econometric models-an application to the U.S. mortgage default risk

This study aims to bridge the gap between two perspectives of explainability−machine learning and engineering, and economics and standard econometrics−by applying three marginal measurements. The existing real estate literature has primarily used econometric models to analyze the factors that affect the default risk of mortgage loans. However, in this study, we estimate a default risk model using a machine learning-based approach with the help of a U.S. securitized mortgage loan database. Moreover, we compare the economic explainability of the models by calculating the marginal effect and marginal importance of individual risk factors using both econometric and machine learning approaches. Machine learning-based models are quite effective in terms of predictive power; however, the general perception is that they do not efficiently explain the causal relationships within them. This study utilizes the concepts of marginal effects and marginal importance to compare the explanatory power of individual input variables in various models. This can simultaneously help improve the explainability of machine learning techniques and enhance the performance of standard econometric methods

Penetration of UVA into water and its effects on primary productivity with special reference to water column mixing

Article信州大学理学部附属諏訪臨湖実験所報告 9: 1-11(1995)departmental bulletin pape

Eutrophication and the primary productivity of phytoplankton in Lake Soyang, Korea.

Article信州大学理学部附属諏訪臨湖実験所報告 9: 155-159(1995)departmental bulletin pape

Differentially Expressed Potassium Channels Are Associated with Function of Human Effector Memory CD8+T cells

The voltage-gated potassium channel, Kv1.3, and the Ca2+-activated potassium channel, KCa3.1, regulate membrane potentials in T cells, thereby controlling T cell activation and cytokine production. However, little is known about the expression and function of potassium channels in human effector memory ( EM) CD8+ T cells that can be further divided into functionally distinct subsets based on the expression of the interleukin ( IL)-7 receptor alpha ( IL-7R alpha) chain. Herein, we investigated the functional expression and roles of Kv1.3 and KCa3.1 in EM CD8+ T cells that express high or low levels of the IL-7 receptor alpha chain ( IL-7R alpha(high) and IL-7R alpha(low), respectively). In contrast to the significant activity of Kv1.3 and KCa3.1 in IL-7Rahigh EM CD8+ T cells, IL-7Ralow EM CD8+ T cells showed lower expression of Kv1.3 and insignificant expression of KCa3.1. Kv1.3 was involved in the modulation of cell proliferation and IL-2 production, whereas KCa3.1 affected the motility of EM CD8+ T cells. The lower motility of IL-7Ralow EM CD8+ T cells was demonstrated using transendothelial migration and motility assays with intercellular adhesion molecule 1-and/or chemokine stromal cell-derived factor-1 alpha-coated surfaces. Consistent with the lower migration property, IL-7Ralow EM CD8+ T cells were found less frequently in human skin. Stimulating IL-7Ralow EM CD8+ T cells with IL-2 or IL-15 increased their motility and recovery of KCa3.1 activity. Our findings demonstrate that Kv1.3 and KCa3.1 are differentially involved in the functions of EM CD8+ T cells. The weak expression of potassium channels in IL-7Ralow EM CD8+ T cells can be revived by stimulation with IL-2 or IL-15, which restores the associated functions. This study suggests that IL-7Rahigh EM CD8+ T cells with functional potassium channels may serve as a reservoir for effector CD8+ T cells during peripheral inflammation.112Ysciescopu

PRIMARY PRODUCTION OF PHYTOPLANKTON AND MACROPHYTES IN AN EUTROPHIC LAGOON, LAKE KYUNGPO, KOREA

Primary production of phytoplankton and macrophytes are measured in a eutrophic lagoon, Lake Kyungpo, where 86% of the lake is inhabited by macrophytes. Phytoplankton standing crop was high, 40-130 mgChl/m³, but productivity per unit area was suppressed low by the light deficiency due to high content of inorganic suspended particles. Contribution of phytoplankton and macrophytes to the total annual production was 55% and 45%, respectively. Allochthonous organic input estimated from BOD was 36% of total organic matter supply. Nitrogen seems to be the limiting nutrient for phytoplankton, since nitrate is often depleted in the water column of macrophyte-growing region and N/P ratio is low. Turbulence and the vertical transfer of oxygen and nutrient are strongly suppressed by the dense population of macrophytes and the chemocline of high stability caused by saline bottom water.Article信州大学理学部付属諏訪臨湖実験所報告 7: 99-103(1991)departmental bulletin pape

EUTROPHICATION OF THE MAJOR RESERVOIRS IN KOREA

Trophic state of several major reservoirs in Korea are reviewed. Most of large reservoirs are mesotrophic to eutrophic, suffering bluegreen algal blooms. Recently many reservoirs are being eutrophied at high rate mainly due to the increase of excretion by livestock in watershed and netcage-type fishfarms within the lake basins. The trophic state changes of Lake Soyang, from oligotrophy to eutrophy in recent 10 years, are presented as a case study of rapid eutrophication. Chlorophyll a concentration increased from ca. 3mg/m³ in early 1980s to 15 mg/m³ in 1989. The dominant phytoplankton species in summer are changed from Peridinium to Anabaena since 1986 and the standing crop of Anabaena has been increasing. Secchidisc depth decreased from 5 to 1m. TP increased from 7 to 20 mgP/m³. The rate of hypolimnetic oxygen deficit increased year to year from 0.028 mgO₂/cm²/day in 1986 to 0.094 in 1989. Fishfarms within the lake are the major phosphorus source in Lake Soyang exceeding the total phosphorus loading from the watershed. This high rate of eutrophication is expected to persist in next decade.Article信州大学理学部付属諏訪臨湖実験所報告 7: 21-29(1991)departmental bulletin pape

Acute viral gastroenteritis in children hospitalized in Iksan, Korea during December 2010-June 2011

PurposeViral etiology is common in cases of children with acute diarrhea, and antibiotic therapy is usually not required. Therefore, it is important to determine the distribution of common viruses among children hospitalized with acute diarrhea.MethodsWe included 186 children who suffered from acute diarrhea and were hospitalized at the Wonkwang University Hospital Pediatric ward from December 1, 2010 to June 30, 2011 in this study. Stool samples were collected and multiplex reverse transcriptase polymerase chain reaction (multiplex RT-PCR) was used to simultaneously determine the viral etiology such as rotavirus, norovirus, astrovirus, or adenovirus.ResultsCausative viruses were detected in 72 of the 186 cases (38.7%). The mean age of the virus-positive cases was 1 year and 9 months (range, 1 month to 11 years). Rotavirus was detected in 50/186 (26.9%); norovirus, in 18/186 (9.7%); and astrovirus, in 3/186 cases (1.6%). Adenovirus was not detected in any of the cases. Proportions of norovirus genogroups I and II were 21.1% and 78.9%, respectively. Four of the 51 rotavirus-positive cases (7.8%) had received rotavirus vaccination at least once. The mean duration of diarrhea was 2.8 days (range, 1 to 10 days) and vomiting occurred in 39 of the 72 cases (54.2%).ConclusionViral etiology was confirmed in about one-third of the children with acute diarrhea, and the most common viral agent was rotavirus, followed by norovirus

The Impact of Body Mass Index on Pancreatic Fistula After Pancreaticoduodenectomy in Asian Patients on the Basis of Asia-Pacific Perspective of Body Mass Index

 Context Several surgical complications are related to obesity. Objective This study evaluated the impact of obesity on pancreatic fistula after pancreaticoduodenectomy. Design We retrospectively reviewed the medical records of 159 patients who underwent pancreaticoduodenectomy between October 2002 and December 2008. Setting The patients were divided according to the body mass index as obese (body mass index equal to, or greater than, 25 kg/m2), or normal (body mass index less than 25 kg/m2). Methods Univariate and multivariate analyses were applied. Two-tailed P values less than 0.05 were considered as significant. Results Forty-six patients (28.9%) were obese and 113 patients (71.1%) were normal-weight. Obese group had a significantly higher incidence of pancreatic fistula and a greater amount of intraoperative blood loss. Other surgical complications were not significantly different between the two groups. Multivariate analysis found obesity, small pancreatic duct size (less than, or equal to, 3 mm), intraoperative blood loss, and combined resection as significant factors affecting pancreatic fistula. Conclusions Obese patients have an increased risk for pancreatic fistula after pancreaticoduodenectomy.