927 research outputs found

    Is Aging the Important Factor for Sustainable Agricultural Development in Korea? Evidence From the Relationship Between Aging and Farm Technical Efficiency

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    This paper examines the effects of aging and income subsidies on farm efficiency in Korea by utilizing the Korean Farm Household Economic Survey from 2008 to 2015. A stochastic frontier model with a non-monotonic assumption on the effect of efficiency factors is implemented to reflect a super aging and less developed production structure in Korean agriculture. This study finds continuously decreasing farm efficiency with age, which contradicts the commonly assumed inverted-U relationship between age and productivity. Especially, we find that labor is the most important factor to explain recent farm efficiency losses in Korea. Furthermore, this paper finds that the Korean income subsidy has a negative effect on farm efficiency. Our results provide two policy implications for the government of Korea. First, even though the “Returns to the Farm and Rural program” is appropriate, Korea should modify the program to encourage more young people to participate this program rather than old people, in order to attain the sustainable development of the agricultural sector. Second, a policy maker in Korea should consider a coupled subsidy that is directly related to farm production rather than a decoupled subsidy, regardless of the lower efficiency of the coupled subsidy in achieving agricultural development

    Cytomegalovirus colitis in immunocompetent patients

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    Soil-Pile Interaction Analysis using FE-BE Coupling in Frequency Domain

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    In this study, a numerical method for soil-pile interaction problems in multi-layered half-plane is developed in frequency domain using FE-BE coupling technique. The soil-pile interaction system is divided into two parts, so-called near field and far field. In the near field, beam elements are used for modeling pile and plane-strain finite elements for surrounding soil media. Also, a superstructure is considered as a lumped mass on a pile. In the far field, layered soil media is modeled by boundary element formulation using the dynamic fundamental solution. Then, these two fields are assembled using FE-BE coupling technique. This coupled numerical method automatically satisfies the radiation conditions because the far field boundary element formulation can handle the radiation conditions in a half plane. Additionally, the difference of relative displacement at the interface between soil and pile is considered by applying interface spring elements. In order to verify the proposed method for soil-pile interaction system, the dynamic responses of a pile in a multi-layered half-plane are performed and the numerical results are compared with the measured values from experiments. It is shown that the developed method can be an efficient numerical tool to solve the dynamic response of a pile buried in a multi-layered half plane

    Identification of protein functions using a machine-learning approach based on sequence-derived properties

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    <p>Abstract</p> <p>Background</p> <p>Predicting the function of an unknown protein is an essential goal in bioinformatics. Sequence similarity-based approaches are widely used for function prediction; however, they are often inadequate in the absence of similar sequences or when the sequence similarity among known protein sequences is statistically weak. This study aimed to develop an accurate prediction method for identifying protein function, irrespective of sequence and structural similarities.</p> <p>Results</p> <p>A highly accurate prediction method capable of identifying protein function, based solely on protein sequence properties, is described. This method analyses and identifies specific features of the protein sequence that are highly correlated with certain protein functions and determines the combination of protein sequence features that best characterises protein function. Thirty-three features that represent subtle differences in local regions and full regions of the protein sequences were introduced. On the basis of 484 features extracted solely from the protein sequence, models were built to predict the functions of 11 different proteins from a broad range of cellular components, molecular functions, and biological processes. The accuracy of protein function prediction using random forests with feature selection ranged from 94.23% to 100%. The local sequence information was found to have a broad range of applicability in predicting protein function.</p> <p>Conclusion</p> <p>We present an accurate prediction method using a machine-learning approach based solely on protein sequence properties. The primary contribution of this paper is to propose new <it>PNPRD </it>features representing global and/or local differences in sequences, based on positively and/or negatively charged residues, to assist in predicting protein function. In addition, we identified a compact and useful feature subset for predicting the function of various proteins. Our results indicate that sequence-based classifiers can provide good results among a broad range of proteins, that the proposed features are useful in predicting several functions, and that the combination of our and traditional features may support the creation of a discriminative feature set for specific protein functions.</p

    Electronic structures of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films

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    We investigated the electronic structure of multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films using both optical spectroscopy and first-principles calculations. Using artificially stabilized hexagonal RMnO3, we extended the optical spectroscopic studies on the hexagonal multiferroic manganite system. We observed two optical transitions located near 1.7 eV and 2.3 eV, in addition to the predominant absorption above 5 eV. With the help of first-principles calculations, we attribute the low-lying optical absorption peaks to inter-site transitions from the oxygen states hybridized strongly with different Mn orbital symmetries to the Mn 3d3z2-r2 state. As the ionic radius of the rare earth ion increased, the lowest peak showed a systematic increase in its peak position. We explained this systematic change in terms of a flattening of the MnO5 triangular bipyramid

    Effects of beam spinning on the fourth-order particle resonance of 3D bunched beams in high-intensity linear accelerators

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    The aim of this study is to make the parameter space of zero-current phase advance greater than 90?? available to the high-intensity linear accelerator (linac) design and operation, which has been excluded to avoid the envelope instabilities and particle resonances. The earlier study of Cheon et al. [Nucl. Instrum. Methods Phys. Res., Sect. A 1013, 165647 (2021)] reported that the spinning of ion beams can mitigate the fourth-order particle resonance and the associated envelope instability in high-intensity linacs. In the present work, we further investigate the effects of beam spinning on the fourth-order particle resonance in the case of 3D bunched beams with fast acceleration. We also explore the space-charge-driven resonance in the longitudinal plane and confirm that the fourth-order particle resonance can be manifested when the longitudinal zero-current phase advance crz0 is larger than 90?? and the depressed phase advance crz is less than 90??, similar to the transverse case. The beam spinning effects are examined in both transverse and longitudinal planes during beam acceleration through periodic solenoid and quadrupole-doublet focusing channels

    Application of Ganz Surgical Hip Dislocation Approach in Pediatric Hip Diseases

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    Ganz surgical hip dislocation is useful in the management of severe hip diseases, providing an unobstructed view of the femoral head and acetabulum. We present our early experience with this approach in pediatric hip diseases. Twenty-three hips of 21 patients with pediatric hip diseases treated using the Ganz surgical hip dislocation approach were the subjects of this study. The average age at the time of surgery was 15.7 years. There were 15 male and 6 female patients who were followed for an average of 15.1 months (range, 6 to 29 months). Diagnoses included hereditary multiple exostoses in 9 hips, slipped capital femoral epiphysis in 7, Legg-Calvé-Perthes disease in 4, osteoid osteoma in 1, pigmented villonodular synovitis in 1, and neonatal septic hip sequelae in 1. Medical records were reviewed to record diagnoses, principal surgical procedures, operative time, blood loss, postoperative rehabilitation, changes in the range of hip joint motion, and complications. Femoral head-neck osteochondroplasty was performed in 17 patients, proximal femoral realignment osteotomy in 6, open reduction and subcapital osteotomy for slipped capital femoral epiphysis (SCFE) in 2, core decompression and bone grafting in 2, hip distraction arthroplasty in 2, and synovectomy in 2. Operative time averaged 168.6 minutes when only osteochondroplasty and/or synovectomy were performed. Hip flexion range improved from a preoperative mean of 84.7 degrees to a mean of 115.0 degrees at the latest follow-up visit. Early continuous passive motion and ambulation were stressed in rehabilitation. No avascular necrosis of the femoral head was noted up to the time of the latest follow-up visit, except for in one SCFE patient whose surgical intervention was delayed for medical reasons. Ganz surgical hip dislocation provides wide exposure of the femoral head and neck, which enables complete and precise evaluation of the femoral head and neck contour. Hence, the extensive impinging bump can be excised meticulously, and the circulation of the femoral head can be monitored during surgery. The Ganz procedure was useful in severe pediatric hip diseases and allowed for quick rehabilitation with fewer complications.Y