766 research outputs found
Matching with multiple criteria and its application to health disparities research
Matching is a popular nonparametric covariate adjustment strategy in
empirical health services research. Matching helps construct two groups
comparable in many baseline covariates but different in some key aspects under
investigation. In health disparities research, it is desirable to understand
the contributions of various modifiable factors, like income and insurance
type, to the observed disparity in access to health services between different
groups. To single out the contributions from the factors of interest, we
propose a statistical matching methodology that constructs nested matched
comparison groups from, for instance, White men, that resemble the target
group, for instance, black men, in some selected covariates while remaining
identical to the white men population before matching in the remaining
covariates. Using the proposed method, we investigated the disparity gaps
between white men and black men in the US in prostate-specific antigen (PSA)
screening based on the 2020 Behavioral Risk Factor Surveillance System (BFRSS)
database. We found a widening PSA screening rate as the white matched
comparison group increasingly resembles the black men group and quantified the
contribution of modifiable factors like socioeconomic status. Finally, we
provide code that replicates the case study and a tutorial that enables users
to design customized matched comparison groups satisfying multiple criteria
Tidal mixing in the South China Sea : an estimate based on the internal tide energetics
Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 107–124, doi:10.1175/JPO-D-15-0082.1.By taking into account the contributions of both locally and remotely generated internal tides, the tidal mixing in the Luzon Strait (LS) and the South China Sea (SCS) is investigated through internal-tide simulation and energetics analysis. A three-dimensional nonhydrostatic high-resolution model driven by four primary tidal constituents (M2, S2, K1, and O1) is used for the internal-tide simulation. The baroclinic energy budget analysis reveals that the internal tides radiated from the LS are the dominant energy source for the tidal dissipation in the SCS. In the LS, the estimated depth-integrated turbulent kinetic energy dissipation exceeds O(1) W m−2 atop the two subsurface ridges, with a dissipation rate of >O(10−7) W kg−1 and diapycnal diffusivity of ~O(10−2) m2 s−1. In the SCS, the most intense turbulence occurs in the deep-water basin with a dissipation rate of O(10−8–10−6) W kg−1 and diapycnal diffusivity of O(10−3–10−1) m2 s−1 within the ~2000-m water column above the seafloor as well as in the shelfbreak region with a dissipation rate of O(10−7–10−6) W kg−1 and diapycnal diffusivity of O(10−4–10−3) m2 s−1. These estimated values are consistent with observations reported in previous studies and are at least one order of magnitude larger than those based solely on locally generated internal tides.This work is jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11010304, XDA11010204), the MOST of China (2014CB953904), the Knowledge Innovation Program of the Chinese Academy of Sciences (SQ201305), and National Natural Science Foundation of China (41376021, 41306013). ZL’s participation of this work was supported by the National Natural Science Foundation of China (41476006), the Natural Science Foundation of Fujian Province of China (2015J06010), and the National Basic Research Program of China (2012CB417402).2016-07-0
Learning Accurate Entropy Model with Global Reference for Image Compression
In recent deep image compression neural networks, the entropy model plays a
critical role in estimating the prior distribution of deep image encodings.
Existing methods combine hyperprior with local context in the entropy
estimation function. This greatly limits their performance due to the absence
of a global vision. In this work, we propose a novel Global Reference Model for
image compression to effectively leverage both the local and the global context
information, leading to an enhanced compression rate. The proposed method scans
decoded latents and then finds the most relevant latent to assist the
distribution estimating of the current latent. A by-product of this work is the
innovation of a mean-shifting GDN module that further improves the performance.
Experimental results demonstrate that the proposed model outperforms the
rate-distortion performance of most of the state-of-the-art methods in the
industry
An Experimental Study on the Shape Changes of TiO 2
Titanium dioxide (TiO2) nanocrystals of different shape were successfully synthesized in a new microemulsion system through a solvothermal process. The TiO2 nanocrystals were prepared from the reaction of tetrabutyl titanate (TBT), H2O, and oleic acid (OA), which were used as solvent and surfactant at 300∘C and 240∘C in a stainless steel autoclave. The sphere, polygon, and rhombus-shaped nanocrystals have been prepared at 300∘C and the dot- and- rod shaped nanocrystals have been synthesized at 240∘C. The effect of the reaction time on the shape and size of TiO2 nanocrystals in this method was studied in the present paper. The size distribution of TiO2 nanocrystals prepared at 300∘C for different hours is also studied. In addition, an attempt to describe the mechanism of shape change of TiO2 nanocrystals was presented in this paper
Schizophrenia plausible protective effect of microRNA-137 is potentially related to estrogen and prolactin in female patients
BackgroundSchizophrenia (SCZ) is a serious chronic mental disorder. Our previous case–control genetic association study has shown that microRNA-137 (miR-137) may only protect females against SCZ. Since estrogen, an important female sex hormone, exerts neuroprotective effects, the relationship between estrogen and miR-137 in the pathophysiology of SCZ was further studied in this study.MethodsGenotyping of single-nucleotide polymorphism rs1625579 of miR-137 gene in 1,004 SCZ patients and 896 healthy controls was conducted using the iMLDR assay. The effect of estradiol (E2) on the miR-137 expression was evaluated on the human mammary adenocarcinoma cell line (MCF-7) and the mouse hippocampal neuron cell line (HT22). The relationships between serum E2, prolactin (PRL), and peripheral blood miR-137 were investigated in 41 SCZ patients and 43 healthy controls. The miR-137 and other reference miRNAs were detected by real-time fluorescent quantitative reverse transcription-PCR.ResultsBased on the well-known SNP rs1625579, the distributions of protective genotypes and alleles of the miR-137 gene were not different between patients and healthy controls but were marginally significantly lower in female patients. E2 upregulated the expression of miR-137 to 2.83 and 1.81 times in MCF-7 and HT22 cells, respectively. Both serum E2 and blood miR-137 were significantly decreased or downregulated in SCZ patients, but they lacked expected positive correlations with each other in both patients and controls. When stratified by sex, blood miR-137 was negatively correlated with serum E2 in female patients. On the other hand, serum PRL was significantly increased in SCZ patients, and the female patients had the highest serum PRL level and a negative correlation between serum PRL and blood miR-137.ConclusionThe plausible SCZ-protective effect of miR-137 may be female specific, of which the underlying mechanism may be that E2 upregulates the expression of miR-137. This protective mechanism may also be abrogated by elevated PRL in female patients. These preliminary findings suggest a new genetic/environmental interaction mechanism for E2/miR-137 to protect normal females against SCZ and a novel E2/PRL/miR-137-related pathophysiology of female SCZ, implying some new antipsychotic ways for female patients in future
- …