30 research outputs found
Bad pixel modified interpolation for astronomical images
We present a new method of interpolation for the pixel brightness estimation
in astronomical images. Our new method is simple and easily implementable. We
show the comparison of this method with the widely used linear interpolation
and other interpolation algorithms using one thousand astronomical images
obtained from the Sloan Digital Sky Survey. The comparison shows that our
method improves bad pixels brightness estimation with four times lower mean
error than the presently most popular linear interpolation and has a better
performance than any other examined method. The presented idea is flexible and
can be also applied to presently used and future interpolation methods. The
proposed method is especially useful for large sky surveys image reduction but
can be also applied to single image correction.Comment: 16 pages, 10 figures. Printed in PASP, September 201
Single-Shot Electron Imaging of Dopant-Induced Nanoplasmas
We present single-shot electron velocity-map images of nanoplasmas generated from doped helium nanodroplets and neon clusters by intense near-infrared and mid-infrared laser pulses. We report a large variety of signal types, most crucially depending on the cluster size. The common feature is a two-component distribution for each single-cluster event: a bright inner part with nearly circular shape corresponding to electron energies up to a few eV, surrounded by an extended background of more energetic electrons. The total counts and energy of the electrons in the inner part are strongly correlated and follow a simple power-law dependence. Deviations from the circular shape of the inner electrons observed for neon clusters and large helium nanodroplets indicate non-spherical shapes of the neutral clusters. The dependence of the measured electron energies on the extraction voltage of the spectrometer indicates that the evolution of the nanoplasma is significantly affected by the presence of an external electric field. This conjecture is confirmed by molecular dynamics simulations, which reproduce the salient features of the experimental electron spectra.The authors are grateful for financial support from the Deutsche Forschungsgemeinschaft (DFG) within the
project MU 2347/12-1 and STI 125/22-2 in the frame of the Priority Programme 1840 ‘Quantum Dynamics
in Tailored Intense Fields’, from the Carlsberg Foundation and the SPARC Programme, MHRD, India. The
ELI-ALPS Project (GINOP-2.3.6-15-2015-00001) is supported by the European Union and co-financed by
the European Regional Development Fund. AH is grateful for financial support from the Basque
Government (Project Reference No. IT1254-19) and from the Spanish Ministerio de Economia y
Competividad (Reference No. CTQ2015-67660-P). Computational and manpower support provided by
IZO-SGI SG Iker of UPV/EHU and European funding (EDRF and ESF) is gratefully acknowledged
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Vitamin D pathway-related gene polymorphisms and their association with metabolic diseases: a literature review
Purpose: Given that the relationship between vitamin D status and metabolic diseases such as obesity and type 2 diabetes (T2D) remains unclear, this review will focus on the genetic associations, which are less prone to confounding, between vitamin D-related single nucleotide polymorphisms (SNPs) and metabolic diseases.
Methods: A literature search of relevant articles was performed on PubMed up to December 2019. Those articles that had examined the association of vitamin D-related SNPs with obesity and/or T2D were included. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data. In total, 73 articles were included in this review.
Results: There is a lack of research focussing on the association of vitamin D synthesis-related genes with obesity and T2D; however, the limited available research, although inconsistent, is suggestive of a protective effect on T2D risk. While there are several studies that investigated the vitamin D metabolism-related SNPs, the research focussing on vitamin D activation, catabolism and transport genes is limited. Studies on CYP27B1, CYP24A1 and GC genes demonstrated a lack of association with obesity and T2D in Europeans; however, significant associations with T2D were found in South Asians. VDR gene SNPs have been extensively researched; in particular, the focus has been mainly on BsmI (rs1544410), TaqI (rs731236), ApaI (rs7975232) and FokI (rs2228570) SNPs. Even though the association between VDR SNPs and metabolic diseases remain inconsistent, some positive associations showing potential effects on obesity and T2D in specific ethnic groups were identified.
Conclusion: Overall, this literature review suggests that ethnic-specific genetic associations are involved. Further research utilizing large studies is necessary to better understand these ethnic-specific genetic associations between vitamin D deficiency and metabolic diseases
