4,596 research outputs found
Illumination Estimation Based Color to Grayscale Conversion Algorithms
In this paper, a new adaptive approach, namelythe illumination estimation approach is introduced into the colorto grayscale conversion technique. In this approach, someassumptions will be made to calculate the weight contribution ofred, green, and blue components during the conversion process.Two color to grayscale conversion algorithms are developedunder this approach, namely the Gray World Assumption Colorto Grayscale Conversion (GWACG) and Shade of GrayAssumption Color to Grayscale (SGACG) conversion algorithms.Based on the extensive experimental results, the proposedalgorithms outperform the conventional conversion techniquesby producing resultant grayscale images with higher brightness,contrast, and amount of details preserved. For this reason, theseproposed algorithms are suitable for pre- and post- processing ofdigital images
a mixed-method approach
Background Sedentary behaviours (SB) can be characterized by low energy
expenditure in a reclining position (e.g., sitting) often associated with work
and transport. Prolonged SB is associated with increased risk for chronic
conditions, and due to technological advances, the working population is in
office settings with high occupational exposure to SB. This study aims to
assess SB among office workers, as well as barriers and strategies towards
reducing SB in the work setting. Methods Using a mixed-methods approach guided
by the socio-ecological framework, non-academic office workers from a
professional school in a large public university were recruited. Of 180
eligible office workers, 40 enrolled and completed all assessments. Self-
reported and objectively measured SB and activity levels were captured. Focus
group discussion (FGD) were conducted to further understand perceptions,
barriers, and strategies to reducing workplace SB. Environmental factors were
systematically evaluated by trained research staff using an adapted version of
the Checklist for Health Promotion Environments at Worksites (CHEW). Thematic
analysis of FGD was conducted and descriptive analysis of quantitative data
was performed. Results The sample was mostly Chinese (n = 33, 80 %) with a
total of 24 (60 %) female participants. Most participants worked five days a
week for about 9.5(0.5) hrs/day. Accelerometer data show that participants
spend the majority of their days in sedentary activities both on workdays
(76.9 %) and non-workdays (69.5 %). Self-report data confirm these findings
with median sitting time of 420(180) minutes at work. From qualitative
analyses, major barriers to reducing SB emerged, including the following
themes: workplace social and cultural norms, personal factors, job scope, and
physical building/office infrastructure. CHEW results confirm a lack of
support from the physical infrastructure and information environment to
reducing SB. Conclusions There is high SB among office workers in this sample.
We identified multiple levels of influence for prolonged occupational SB, with
a particular emphasis on workplace norms and infrastructure as important
barriers to reducing SB and increasing PA. A larger, representative sample of
the Singaporean population is needed to confirm our findings but it seems that
any intervention aimed at reducing SB in the workplace should target
individual, environmental, and organizational levels
The Yuan-Tseh Lee Array for Microwave Background Anisotropy
The Yuan-Tseh Lee Array for Microwave Background Anisotropy (AMiBA) is the
first interferometer dedicated to studying the cosmic microwave background
(CMB) radiation at 3mm wavelength. The choice of 3mm was made to minimize the
contributions from foreground synchrotron radiation and Galactic dust emission.
The initial configuration of seven 0.6m telescopes mounted on a 6-m hexapod
platform was dedicated in October 2006 on Mauna Loa, Hawaii. Scientific
operations began with the detection of a number of clusters of galaxies via the
thermal Sunyaev-Zel'dovich effect. We compare our data with Subaru weak lensing
data in order to study the structure of dark matter. We also compare our data
with X-ray data in order to derive the Hubble constant.Comment: accepted for publication in ApJ (13 pages, 7 figures); a version with
high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/pho_highreso.pd
Efficient light-emitting diodes based on nanocrystalline perovskite in a dielectric polymer matrix.
Electroluminescence in light-emitting devices relies on the encounter and radiative recombination of electrons and holes in the emissive layer. In organometal halide perovskite light-emitting diodes, poor film formation creates electrical shunting paths, where injected charge carriers bypass the perovskite emitter, leading to a loss in electroluminescence yield. Here, we report a solution-processing method to block electrical shunts and thereby enhance electroluminescence quantum efficiency in perovskite devices. In this method, a blend of perovskite and a polyimide precursor dielectric (PIP) is solution-deposited to form perovskite nanocrystals in a thin-film matrix of PIP. The PIP forms a pinhole-free charge-blocking layer, while still allowing the embedded perovskite crystals to form electrical contact with the electron- and hole-injection layers. This modified structure reduces nonradiative current losses and improves quantum efficiency by 2 orders of magnitude, giving an external quantum efficiency of 1.2%. This simple technique provides an alternative route to circumvent film formation problems in perovskite optoelectronics and offers the possibility of flexible and high-performance light-emitting displays.The authors acknowledge funding from the Gates Cambridge Trust, the Singapore National Research Foundation (Energy Innovation Programme Office), the KACST-Cambridge University Joint Centre of Excellence, the Royal Society/Sino-British Fellowship Trust, and the Engineering and Physical Sciences Research Council, UK. We also thank Dr. Alessandro Sepe for helpful discussions of the XRD data.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.nanolett.5b0023
RETRACTED: Autoimmunity as the Consequence of a Spontaneous Mutation in Rasgrp1
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Authors.The authors have agreed to retract the paper because of the falsification of the Western blot in Figure 6A. The figure shows a defect in Ras activation, labeled as RasGTP, following TCR engagement, in thymocytes isolated from a RasGRP1 lag mutant mouse strain. This data set is one of several that show signaling and functional deficiencies identified for cells with lost of function of RasGRP. The authors stand by the validity of the other figures, results and interpretation in this paper. This matter was investigated by the Massachusetts Institute of Technology and the Office of Research Integrity at the United States Department of Health & Human Services, which found the figure was falsified by Luk Van Parijs, who is solely responsible. The authors deeply regret any inconvenience resulting from the publication of this data
Electrical transport properties and magnetoresistance of Pr0.67Sr0.33MnO3-NiO composites
A series of polycrystalline bulk samples (Pr0.67Sr0.33MnO3)1-x/ (NiO)x were prepared by solid state reaction, and its structure, electrical transport and magnetoresistance properties were investigated. X-ray analysis showed that parent compound of Pr0.67Sr0.33MnO3 (PSMO) formed in single phase with crystal structure of orthorhombic while secondary phase of NiO can be detected with the addition of composite. The electrical properties showed that the resistivity increased with the addition of NiO due to enhancement of spin dependent-tunneling scattering across the artificial grain boundaries of NiO layer. Magnetic field dependence MR curve at various temperatures clearly indicates that extrinsic magnetoresistance had been enhanced due to addition of NiO as the artificial grain boundary
The Long Distance Contribution to
We calculate the long distance contribution to
decays by the use of a vector meson dominance model, in which the -meson
plays the central role. The branching ratios obtained are and a few
times for the resonance and non-resonance regions respectively. The
analysis includes a calculation of , consistent with the
experimental value.Comment: Latex file, 10 pages, no figur
International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol
Epilepsy is one of the most common chronic neurological diseases in veterinary practice. Magnetic resonance imaging (MRI) is regarded as an important diagnostic test to reach the diagnosis of idiopathic epilepsy. However, given that the diagnosis requires the exclusion of other differentials for seizures, the parameters for MRI examination should allow the detection of subtle lesions which may not be obvious with existing techniques. In addition, there are several differentials for idiopathic epilepsy in humans, for example some focal cortical dysplasias, which may only apparent with special sequences, imaging planes and/or particular techniques used in performing the MRI scan. As a result, there is a need to standardize MRI examination in veterinary patients with techniques that reliably diagnose subtle lesions, identify post-seizure changes, and which will allow for future identification of underlying causes of seizures not yet apparent in the veterinary literature.
There is a need for a standardized veterinary epilepsy-specific MRI protocol which will facilitate more detailed examination of areas susceptible to generating and perpetuating seizures, is cost efficient, simple to perform and can be adapted for both low and high field scanners. Standardisation of imaging will improve clinical communication and uniformity of case definition between research studies. A 6–7 sequence epilepsy-specific MRI protocol for veterinary patients is proposed and further advanced MR and functional imaging is reviewed
Profiling and Functional Analyses of MicroRNAs and Their Target Gene Products in Human Uterine Leiomyomas
Human uterine leiomyomas (ULM) are characterized by dysregulation of a large number of genes and non-coding regulatory microRNAs. In order to identify microRNA::mRNA associations relevant to ULM pathogenesis, we examined global correlation patterns between the altered microRNA expression and the predicted target genes in ULMs and matched myometria.Patterns of inverse association of microRNA with mRNA expression in ULMs revealed an involvement of multiple candidate pathways, including extensive transcriptional reprogramming, cell proliferation control, MAP kinase, TGF-beta, WNT, JAK/STAT signaling, remodeling of cell adhesion, and cell-cell and cell-matrix contacts. We further examined the correlation between the expression of the selected target gene protein products and microRNAs in thirty-six paired sets of leiomyomas and matched myometria. We found that a number of dysregulated microRNAs were inversely correlated with their targets at the protein level. The comparative genomic hybridization (CGH) in eight ULM patients revealed that partially shared deletions of two distinct chromosomal regions might be responsible for loss of cancer-associated microRNA expression and could thus contribute to the ULM pathogenesis via deregulation of target mRNAs. Last, we functionally tested the repressor effects of selected cancer-related microRNAs on their predicted target genes in vitro.We found that some but not all of the predicted and inversely correlated target genes in ULMs can be directly regulated by microRNAs in vitro. Our findings provide a broad overview of molecular events underlying the tumorigenesis of uterine ULMs and identify select genetic and regulatory events that alter microRNA expression and may play important roles in ULM pathobiology by positively regulating tumor growth while maintaining the non-invasive character of ULMs
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