4,384 research outputs found
Direct Virtual Memory Access from FPGA for High-Productivity Heterogeneous Computing
Heterogeneous computing utilizing both CPU and FPGA requires access to data in the main memory from both devices. While a typical system relies on software executing on the CPU to orchestrate all data movements between the FPGA and the main memory, our demo presents a complementary FPGA-centric approach that allows gateware to directly access the virtual memory space as part of the executing process without involving the CPU. A caching address translation buffer was implemented alongside the user FPGA gateware to provide runtime mapping between virtual and physical memory addresses. The system was implemented on a commercial off-the-shelf FPGA add-on card to demonstrate the viability of such approach in low-cost systems. Experiment demonstrated reasonable performance improvement when compared to a typical software-centric implementation; while the number of context switches between FPGA and CPU in both kernel and user mode was significantly reduced, freeing the CPU for other concurrent user tasks. © 2013 IEEE.published_or_final_versio
Selective Growth of a C-70 Crystal in a Mixed Solvent System: From Cube to Tube
Cube- and tube-shaped C-70 crystals were obtained selectively by reprecipitation using a combination of mesitylene (good solvent) and isopropyl alcohol (poor solvent). Both crystals include mesitylene molecules in their lattices; the ratios of C-70 to mesitylene were 1:2 in C-70 cubes and 1:0.7 in C-70 tubes. The volume ratio of mesitylene to IPA is a key parameter for the selective growth of C-70 cubes and C-70 tubes, rather than the supersaturation ratio, which governs crystal morphology in many other cases. Thus, we propose that the absolute amount of mesitylene near C-70 molecules determines the crystallization pathways for forming the C-70 2(mesitylene) or C-70 0.7(mesitylene) phase, which finally result in C-70 cubes or C-70 tubes, respectively.X111411Ysciescopu
Electronic structures and magnetic properties of RB4 (R=Yb,Pr,Gd,Tb,Dy)
Most rare-earth tetraborides RB4 have antiferromagnetic ground states except for YbB4 and PrB4. We have investigated the electronic structures and magnetic properties of RB4 (R=Yb, Pr, Gd, Tb, Dy) employing the first-principles total energy band method. It is found that YbB4 has the paramagnetic ground state, while the other tetraborides are in the magnetic ground state, which is in agreement with experiments. We have obtained the spin and orbital magnetic moments and discussed the importance of the spin-orbit interaction and the on-site Coulomb repulsion (U) in these systems. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3058707]ope
A Study of Initialization in Linux and OpenBSD
The code that initializes a system can be notoriously difficult to understand. In secure systems, initialization is critical for establishing a starting state that is secure. This paper explores two architectures used for bringing an operating system to its initial state, once the operating system gains control from the boot loader. Specifically, the
ways in which the OpenBSD and Linux operating systems handle initialization are dissected
Unique Crystallization of Fullerenes: Fullerene Flowers
Solution-phase crystallization of fullerene molecules strongly depends on the types of solvent and their ratios because solvent molecules are easily included in the crystal lattice and distort its structure. The C-70 (solute)-mesitylene (solvent) system yields crystals with various morphologies and structures, such as cubes, tubes, and imperfect rods. Herein, using C-60 and C-70 dissolved in mesitylene, we present a novel way to grow unique flower-shaped crystals with six symmetric petals. The different solubility of C-60 and C-70 in mesitylene promotes nucleation of C-70 with sixfold symmetry in the early stage, which is followed by co-crystallization of both C-60 and C-70 molecules, leading to lateral petal growth. Based on the growth mechanism, we obtained more complex fullerene crystals, such as multi-deck flowers and tube-flower complexes, by changing the sequence and parameters of crystallization.1134Ysciescopu
Growth characteristics and productivity of tall fescue new variety ‘Purumi’ in South Korea
A new tall fescue variety (Festuca arundinacea Schreb.) named ‘Purumi’ was developed by the National Institute of Animal Science, Rural Development Administration, South Korea from 1999 to 2007. For synthetic seed production of this new variety, 5 superior clones: EFa9108, EFa0010, EFa0020, EFa0108 and EFa0202 were selected and polycrossed. The agronomic growth characteristics and forage production capability of the seeds were studied at Cheonan from 2004 to 2005, and regional trials were conducted in Cheonan, Pyungchang, Jeju and Jinju from 2008 to 2010. Purumi showed enhanced winter hardiness, disease resistance, and regrowth ability as compared to Fawn. The dry matter yield of Purumi was about 5.6% (16.821 kg/ha) higher than that of Fawn. However, the nutritive value of both varieties was similar. Since this new variety of tall fescue, Purumi has been developed and distributed with its most remarkable adaptability for Korean climates and superior value as a livestock feed, it is expected to play an important role in restoration of the pasture industry in Korea.Key words: Tall fescue, Purumi, variety, forage, grassland
Impact of visceral fat on skeletal muscle mass and vice versa in a prospective cohort study: The Korean Sarcopenic Obesity Study (KSOS)
Objectives: Sarcopenia and visceral obesity have been suggested to aggravate each other, resulting in a vicious cycle. However, evidence based on prospective study is very limited. Our purpose was to investigate whether visceral fat promotes a decrease in skeletal muscle mass and vice versa. Methods: We observed changes in anthropometric and body composition data during a follow-up period of 27.6±2.8 months in 379 Korean men and women (mean age 51.9±14.6 years) from the Korean Sarcopenic Obesity Study (KSOS). Appendicular lean soft tissue (ALST) mass was calculated using dual-energy X-ray absorptiometry, and visceral fat area (VFA) was measured using computed tomography at baseline and follow-up examination. Results: ALST mass significantly decreased, whereas trunk and total fat mass increased in both men and women despite no significant change in weight and body mass index. In particular, women with visceral obesity at baseline had a greater decrease in ALST mass than those without visceral obesity (P=0.001). In multiple linear regression analysis, baseline VFA was an independent negative predictor of the changes in ALST after adjusting for confounding factors including age, gender, life style and body composition parameters, insulin resistance, high sensitivity C-reactive protein and vitamin D levels (P=0.001), whereas the association between baseline ALST mass and changes in VFA was not statistically significant (P=0.555). Conclusions: This longitudinal study showed that visceral obesity was associated with future loss of skeletal muscle mass in Korean adults. These results may provide novel insight into sarcopenic obesity in an aging society
Adaptation and validation of the Chinese version of Dyspnoea-12 scale in individuals with chronic obstructive pulmonary disease
Introduction: Dyspnoea-12 scale is a validated assessment tool, capturing the perception of dyspnoea and its physical and affective effects in individuals with chronic obstructive pulmonary disease (COPD). A validated version for the Chinese-speaking population has been unavailable. Objective: To develop a Chinese version of D-12 (D-12-C) scale and evaluate its validity and reliability. Methods: D-12 was translated from English to traditional Chinese in collaboration with a physician and a linguist. Back translation was adopted to ensure accuracy of the translation. A total of 155 COPD patients were recruited to test the reliability and validity of the D-12-C scale. Internal reliability and test-retest reliability were measured with Cronbach's alpha coefficient and intra-class correlation coefficient, respectively. Construct validity was assessed through exploratory factor analysis (EFA). Concurrent validity was assessed by the correlation of D-12-C total score and sub-scores and the Chinese version of Saint George's Respiratory Questionnaire (SGRQ), 36-Item Short Form Health Survey (SF-36), COPD Assessment Test (CAT) and Hospital Anxiety and Depression Scale (HADS) total score and sub-scores. Results: The two-factor structure of D-12-C was confirmed by EFA. D-12-C and its sub-scores demonstrated high level of internal reliability (Cronbach's alpha = 0.88) and moderate level of test-retest reliability. D-12-C total score, physical and affective sub-scores were significantly correlated to SGRQ total score (rs = 0.59, p < 0.001) and activity sub-score (rs = 0.38, p = 0.006), SF-36 mental health sub-score (rs = −0.36, p < 0.001), CAT (rs = 0.56, p < 0.001), HADS anxiety (rs = 0.51, p < 0.001) and depression sub-scores (rs = 0.44, p < 0.001). Conclusion: D-12-C scale was developed, which demonstrated satisfactory reliability and validity in measuring dyspnoea among COPD patients
High frequency plant regeneration from mature seedderived callus of Italian ryegrass (Lolium multiflorum) cultivars
In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 mg l-1 2,4-D, 0.5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 30 g l-1 sucrose, 7 mg l-1 AgNO3, 2 mg l-1 CuSO4 and solidified with 3 g l-1 Gelrite. The highest regeneration rate was obtained in MS medium containing 1 mg l-1 2,4-D, 5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 1 mg l-1 thiamine-HCl, 30 g l-1 sucrose, 7 mg l-1 AgNO3, 2 mg l-1 CuSO4 and solidified with 3 g l-1 Gelrite. By using the most effective treatment determined for each parameter, the highest rates of embryogenic callus formation (48.9%) and regeneration (47.6%) were obtained with the Hwasan 101 cultivar. The overall plant regeneration rates of the examined cultivars ranged from 7.5 to 23.2%. Thus, optimization of regeneration frequency using mature seeds as explant material may offer a simple and efficient protocol for Italian ryegrass that may improve molecular breeding of this species
Local Charge of the nu=5/2 Fractional Quantum Hall State
Electrons in two dimensions and strong magnetic fields effectively lose their
kinetic energy and display exotic behavior dominated by Coulomb forces. When
the ratio of electrons to magnetic flux quanta in the system is near 5/2, the
unique correlated phase that emerges is predicted to be gapped with
fractionally charged quasiparticles and a ground state degeneracy that grows
exponentially as these quasiparticles are introduced. Interestingly, the only
way to transform between the many ground states would be to braid the
fractional excitations around each other, a property with applications in
quantum information processing. Here we present the first observation of
localized quasiparticles at nu=5/2, confined to puddles by disorder. Using a
local electrometer to compare how quasiparticles at nu=5/2 and nu=7/3 charge
these puddles, we are able to extract the ratio of local charges for these
states. Averaged over several disorder configurations and samples, we find the
ratio to be 4/3, suggesting that the local charges are e/3 at seven thirds and
e/4 at five halves, in agreement with theoretical predictions. This
confirmation of localized e/4 quasiparticles is necessary for proposed
interferometry experiments to test statistics and computational ability of the
state at nu=5/2.Comment: 6 pages, 4 figures corrected titl
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