10,789 research outputs found
Convergence of wavelet thresholding estimators of differential operators
AbstractWavelet shrinkage is a strategy to obtain a nonlinear approximation to a given signal. The shrinkage method is applied in different areas, including data compression, signal processing and statistics. The almost everywhere convergence of resulting wavelet series has been established in [T. Tao, On the almost everywhere convergence of wavelet summation methods, Appl. Comput. Harmon. Anal. 3 (1996) 384β387] and [T. Tao, B. Vidakovic, Almost everywhere behavior of general wavelet shrinkage operators, Appl. Comput. Harmon. Anal. 9 (2000) 72β82]. With a representation of fβ² in terms of wavelet coefficients of f, we are interested in considering the influence of wavelet thresholding to f on its derivative fβ². In this paper, for the representation of differential operators in nonstandard form, we establish the almost everywhere convergence of estimators as threshold tends to zero
Binary population synthesis study on supersoft X-ray phase of single degenerate type Ia supernova progenitors
In the single degenerate (SD) scenario for type Ia supernovae (SNe Ia), a
mass-accreting white dwarf is expected to experience a supersoft X-ray source
(SSS) phase. However, some recent observations showed that the expected number
of the mass-accreting WD is much lower than that predicted from theory,
whatever in spiral or elliptical galaxies. In this paper, we did a binary
population synthesis study on the relative duration of the SSS phase to their
whole mass-increasing phase of WDs leading to SNe Ia. We found that for about
40% progenitor systems, the relative duration is shorter than 2% and the
evolution of the mean relative duration shows that it is always smaller than
5%, whatever for young or old SNe Ia. In addition, before SNe Ia explosion,
more than 55% progenitor systems are experiencing a dwarf novae phase, and only
no more than 10% is staying SSS phase. These results are consistent with the
recent observations, and imply that both in early- and late-type galaxies, only
a small fraction of mass-accreting WD resulting in SNe Ia contribute to the
supersoft X-ray flux. So, although our results are not directly related to the
X-ray output of SN Ia progenitor, the low supersoft X-ray luminosity observed
in early type galaxies may have no ability to exclude the validity of SD model.
On the contrary, it is evidence to support the SD scenario.Comment: 9 pages, 5 figures, accepted for publication in RA
Role of ASH1L in Prostate Cancer Metastasis
https://openworks.mdanderson.org/sumexp22/1021/thumbnail.jp
Tolerability and effectiveness of (S)-amlodipine compared with racemic amlodipine in hypertension: A systematic review and meta-analysis
AbstractBackground: Amlodipine is a calcium channel blocker prescribed for the management of angina and hypertension. As a racemic mixture, amlodipine contains (R)- and (S)-amlodipine isomers, but only (S)-amlodipine as the active moiety possesses therapeutic activity. Based on pharmacologic research, it remains uncertain if (S)-amlodipine alone has similar efficacy and fewer associated adverse events (AEs) compared with the racemic mixtures.Objective: The aim of this systematic review and meta-analysis was to determine the effectiveness and tolerability of (S)-amlodipine compared with that of racemic amlodipine.Methods: A systematic literature search was performed using MEDLINE (1966β2009), EMBASE (1966β2009), the Cochrane Central Register of Controlled Trials (issue 3, 2009), the Chinese Biomedical Database (1978β2009), and the China National Knowledge Internet (1980β2009). All randomized controlled trials (RCTs) comparing (S)-amlodipine 2.5 mg and racemic amlodipine 5.0 mg in the treatment of hypertension were included in the review. The outcome measures to be collected were cardiovascular events, systolic blood pressure (SBP), diastolic BP (DBP), and AEs. Quality assessments of clinical trials were conducted using a modified Jadad Scale, with trials being rated as low quality (score 0β3) or high quality (score 4β7). Meta-analysis of the included studies was performed using RevMan software.Results: Of the 229 references identified, 214 were excluded after screening the titles, abstracts, or full texts. Fifteen RCTs were included, of which 13 were in Chinese and 2 in English. Based on the Jadad Scale score, 3 of the RCTs were classified as high quality (score 5 or 6) and the remaining 12 as low quality (score 1β3). None of the trials evaluated cardiovascular events beyond 40 weeks. Meta-analysis of the 15 trials indicated that (S)-amlodipine was not significantly different from racemic amlodipine in the effect on BP. When only high-quality studies were included, after 4 weeks' treatment, the weighted mean difference (WMD) of SBP and DBP decrease (1 study) was β2.84 (95% CI, β6.42 to 0.74) with (S)-amlodipine and β1.71 (95% CI, β3.48 to 0.06) with racemic amlodipine. After 8 weeks' treatment, the WMD of SBP and DBP decrease (2 studies) was β1.13 (95% CI, β5.29 to 3.03) and β1.34 (95% CI, β2.67 to β0.01), respectively. The risk difference (RD) for the number of patients who experienced AEs with (S)-amlodipine and racemic amlodipine was found to be β0.04 (95% CI, β0.06 to β0.02). When all the trials were included, (S)-amlodipine treatment was associated with significantly less edema than racemic amlodipine (RD, β0.02; 95% CI, β0.03 to 0.00); however, when only high-quality studies (2 studies) were included, no difference was found between the 2 groups (RD, 0.01; 95% CI, β0.02 to 0.03). One high-quality study found significant differences in increases in aspartate and alanine aminotransferase activities in the 2 groups (RD, 0.08; 95% CI, 0.01 to 0.05). No significant differences between the 2 groups were found in the incidence of headache (RD, 0.00; 95% CI, β0.02 to 0.01) or flushing (RD, β0.01; 95% CI, β0.02 to 0.00).Conclusions: The majority of the clinical trials comparing (S)-amlodipine and racemic amlodipine treatment were low quality (12/15 [80%]). According to the limited evidence, there were no significant differences between (S)-amlodipine 2.5 mg and racemic amlodipine 5.0 mg in controlling BP. When all the trials were considered, (S)-amlodipine treatment was associated with significantly less edema than racemic amlodipine; however, when only high-quality trials were included, no significant difference was found. More long-term, high-quality RCTs with cardiovascular events as the primary outcome are needed to compare the safety and efficacy of (S)-amlodipine and racemic amlodipine
Large-scale Weakly Supervised Learning for Road Extraction from Satellite Imagery
Automatic road extraction from satellite imagery using deep learning is a
viable alternative to traditional manual mapping. Therefore it has received
considerable attention recently. However, most of the existing methods are
supervised and require pixel-level labeling, which is tedious and error-prone.
To make matters worse, the earth has a diverse range of terrain, vegetation,
and man-made objects. It is well known that models trained in one area
generalize poorly to other areas. Various shooting conditions such as light and
angel, as well as different image processing techniques further complicate the
issue. It is impractical to develop training data to cover all image styles.
This paper proposes to leverage OpenStreetMap road data as weak labels and
large scale satellite imagery to pre-train semantic segmentation models. Our
extensive experimental results show that the prediction accuracy increases with
the amount of the weakly labeled data, as well as the road density in the areas
chosen for training. Using as much as 100 times more data than the widely used
DeepGlobe road dataset, our model with the D-LinkNet architecture and the
ResNet-50 backbone exceeds the top performer of the current DeepGlobe
leaderboard. Furthermore, due to large-scale pre-training, our model
generalizes much better than those trained with only the curated datasets,
implying great application potential
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