1,990 research outputs found
An efficient nonlinear iteration scheme for nonlinear parabolicâhyperbolic system
AbstractA nonlinear iteration method named the PicardâNewton iteration is studied for a two-dimensional nonlinear coupled parabolicâhyperbolic system. It serves as an efficient method to solve a nonlinear discrete scheme with second spatial and temporal accuracy. The nonlinear iteration scheme is constructed with a linearizationâdiscretization approach through discretizing the linearized systems of the original nonlinear partial differential equations. It can be viewed as an improved Picard iteration, and can accelerate convergence over the standard Picard iteration. Moreover, the discretization with second-order accuracy in both spatial and temporal variants is introduced to get the PicardâNewton iteration scheme. By using the energy estimate and inductive hypothesis reasoning, the difficulties arising from the nonlinearity and the coupling of different equation types are overcome. It follows that the rigorous theoretical analysis on the approximation of the solution of the PicardâNewton iteration scheme to the solution of the original continuous problem is obtained, which is different from the traditional error estimate that usually estimates the error between the solution of the nonlinear discrete scheme and the solution of the original problem. Moreover, such approximation is independent of the iteration number. Numerical experiments verify the theoretical result, and show that the PicardâNewton iteration scheme with second-order spatial and temporal accuracy is more accurate and efficient than that of first-order temporal accuracy
Form Factors from QCD Light-Cone Sum Rules
In this work, we calculate the transition form factors of
decaying into within the framework of light-cone sum rules with the
distribution amplitudes (DAs) of -baryon. In the hadronic
representation of the correlation function, we have isolated both the
and the states so that the form factors can be obtained without ambiguity. We investigate the
P-type and A-type current to interpolate the light baryons for a comparison
since the interpolation current for the baryon state is not unique. We also
employ three parametrization models for DAs of in the numerical
calculation. We present the numerical predictions on the form factors and the branching fractions, the averaged
forward-backward asymmetry , the averaged final hadron polarization and the
averaged lepton polarization of the decays,
as well as the ratio of branching ratios , and the predicted
can be consistent with the LHCb data.Comment: 22 pages, 2figur
Preparation and Characterization of a Lecithin Nanoemulsion as a Topical Delivery System
Purpose of this study was to establish a lecithin nanoemulsion (LNE) without any synthetic surfactant as a topical delivery vehicle and to evaluate its topical delivery potential by the following factors: particle size, morphology, viscosity, stability, skin hydration and skin penetration. Experimental results demonstrated that an increasing concentration of soybean lecithin and glycerol resulted in a smaller size LNE droplet and increasing viscosity, respectively. The droplet size of optimized LNE, with the glycerol concentration above 75% (w/w), changed from 92 (F10) to 58 nm (F14). Additionally, LNE, incorporated into o/w cream, improved the skin hydration capacity of the cream significantly with about 2.5-fold increase when the concentration of LNE reached 10%. LNE was also demonstrated to improve the penetrability of Nile red (NR) dye into the dermis layer, when an o/w cream, incorporated with NR-loaded LNE, applied on the abdominal skin of rat in vivo. Specifically, the arbitrary unit (ABU) of fluorescence in the dermis layer that had received the cream with a NR-loaded LNE was about 9.9-fold higher than the cream with a NR-loaded general emulsion (GE). These observations suggest that LNE could be used as a promising topical delivery vehicle for lipophilic compounds
Relationship between gray matter structure and age in children and adolescents with high-functioning autism spectrum disorder
ObjectiveThe present study used magnetic resonance imaging to investigate the difference in the relationship between gray matter structure and age in children and adolescents with autism spectrum disorder (ASD) and typically developing (TD) subjects.MethodsAfter screening T1 structural images from the Autism Brain Imaging Data Exchange (ABIDE) database, 111 children and adolescents (7â18 years old) with high-functioning ASD and 151 TD subjects matched for age, sex and full IQ were included in the current study. By using the voxel-based morphological analysis method, gray matter volume/density (GMV/GMD) maps were obtained for each participant. Then, a multiple regression analysis was performed for ASD and TD groups, respectively to estimate the relationship between GMV/GMD and age with gender, education, site, and IQ scores as covariates. Furthermore, a z-test was used to compare such relationship difference between the groups.ResultsResults showed that compared with TD, the GMD of ASD showed stronger positive correlations with age in the prefrontal cortex, and a stronger negative correlation in the left inferior parietal lobule, and a weaker positive correlation in the right inferior parietal lobule. The GMV of ASD displayed stronger positive correlations with age in the prefrontal cortex and cerebellum.ConclusionThese findings may provide evidence to support that the brain structure abnormalities underlying ASD during childhood and adolescence may differ from each other
Traditional Chinese medicine combined with hormone therapy to treat premature ovarian failure: a meta-analysis of randomized controlled trials
Background: This meta-analysis aimed to provide critically estimated evidence for the advantages and disadvantages of Chinese herbal medicines used for premature ovarian failure (POF), which could provide suggestions for rational treatments.Materials and Methods: The databases searched included MEDLINE, EMBASE, CNKI, VIP, China Dissertation Database, China Important Conference Papers Database, and online clinical trial registry websites. Published and unpublished randomized controlled trials of traditional Chinese medicine (TCM) combined with hormone therapy (HT) and HT alone for POF were assessed up to December 30, 2015. Two authors extracted data and assessed trial quality independently using Cochrane systematic review methods. Meta-analysis was used to quantitatively describe serum hormone levels and Kupperman scores associated with perimenopause symptoms.Results: Seventeen randomized controlled trials involving 1352 participants were selected. Compared with HT alone, although no significant effects were observed in the levels of luteinizing hormone, therapy with TCM combined with HT compared to HT alone effectively altered serum hormone levels of follicle stimulating hormone (P<0.01) and estradiol (P < 0.01), and improved Kupperman index scores (P< 0.01).Conclusions: The reported favorable effects of TCM combined with HT for treating POF patients are better than HT alone.However,the beneficial effects derived from this combination therapy cannot be viewed conclusive.In order to better support the clinical use, more rigorously designed trials are required to provide.Keywords: Traditional Chinese medicine, Hormone therapy, Premature ovarian failure, Meta-analysi
The K giant stars from the LAMOST survey data I: identification, metallicity, and distance
We present a support vector machine classifier to identify the K giant stars
from the LAMOST survey directly using their spectral line features. The
completeness of the identification is about 75% for tests based on LAMOST
stellar parameters. The contamination in the identified K giant sample is lower
than 2.5%. Applying the classification method to about 2 million LAMOST spectra
observed during the pilot survey and the first year survey, we select 298,036 K
giant candidates. The metallicities of the sample are also estimated with
uncertainty of \,dex based on the equivalent widths of Mg and iron lines. A Bayesian method is then developed to estimate the
posterior probability of the distance for the K giant stars, based on the
estimated metallicity and 2MASS photometry. The synthetic isochrone-based
distance estimates have been calibrated using 7 globular clusters with a wide
range of metallicities. The uncertainty of the estimated distance modulus at
\,mag, which is the median brightness of the K giant sample, is about
0.6\,mag, corresponding to % in distance. As a scientific verification
case, the trailing arm of the Sagittarius stream is clearly identified with the
selected K giant sample. Moreover, at about 80\,kpc from the Sun, we use our K
giant stars to confirm a detection of stream members near the apo-center of the
trailing tail. These rediscoveries of the features of the Sagittarius stream
illustrate the potential of the LAMOST survey for detecting substructures in
the halo of the Milky Way.Comment: 24 pages, 20 figures, submitted to Ap
The relationship between social support and erectile dysfunction in middle-aged and older males
BackgroundErectile dysfunction (ED) is a prevalent condition that affects middle-aged and older men, impacting their sexual health and overall wellbeing. We aimed to investigate the relationship between social support and ED among this specific population.MethodsData were collected from the National Health and Nutrition Examination Survey. Social support was assessed through various dimensions, including emotional support, material support, and network support. Multivariate logistic regression was performed to examine the association between social support and ED, and a propensity-score-matched (PSM) analysis was further conducted.ResultsAmong 1938 middle-aged and older males in the United States, 49.9% had a history of ED. ED was more prevalent in older individuals and those with comorbidities such as hypertension, prostate disease, higher serum creatinine level, and mental problems. Males with lower social support scores had a higher weighted rate of ED (P < 0.001). After adjusting for multiple variables in logistic regression analysis, a higher social support score was associated with a 19% lower likelihood of ED (weighted odds ratio [OR] 0.81, 95% confidence interval [CI] 0.66â0.98, P = 0.032). The association remained consistent after propensity score matching (OR 0.80, 95% CI 0.66â0.98, P = 0.028).ConclusionSocial support appears to be associated with a reduced risk of ED in middle-aged and older men. Further research is needed to better understand this relationship and explore interventions that enhance social support, potentially leading to improved sexual health outcomes
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