676 research outputs found
Overcoming the Circular Problem for \gamma-ray Bursts in Cosmological Global Fitting Analysis
Due to the lack of low redshift long Gamma-Ray Bursts (GRBs), the circular
problem has been a severe obstacle for using GRBs as cosmological candles. In
this paper, we present a new method to deal with such a problem in MCMC global
fitting analysis. Assuming that a certain type of correlations between
different observables exists in a subsample of GRBs, for the parameters
involved in the correlation relation, we treat them as free parameters and
determine them simultaneously with cosmological parameters through MCMC
analysis on GRB data together with other observational data. Then the circular
problem is naturally eliminated in this procedure. We take the Ghirlanda
relation as an example while keeping in mind the debate about its physical
validity. Together with SNe Ia, WMAP and SDSS data, we include 27 GRBs with the
reported Ghirlanda relation in our study, and perform MCMC global fitting. We
consider the CDM model and dynamical dark energy models. In each case,
in addition to the constraints on the relevant cosmological parameters, we
obtain the best fit values as well as the distributions of the correlation
parameters and . We find that the observational data sets other than
GRBs can affect and considerably through their degeneracies with the
cosmological parameters. The results on and for different cosmological
models are in well agreement within range. The best fit value of
in all models being analyzed is with . For ,
we have the best value in the range of with . It is
also noted that the distributions of and are generally broader than the
priors used in many studies in literature. (Abriged)Comment: 9 pages, 2 figures, 2 tables, Accepted for publication in Ap
On using the WMAP distance priors in constraining the time evolving equation of state of dark energy
Recently, the WMAP group has published their five-year data and considered
the constraints on the time evolving equation of state of dark energy for the
first time from the WMAP distance information. In this paper, we study the
effectiveness of the usage of these distance information and find that these
compressed CMB information can give similar constraints on dark energy
parameters compared with the full CMB power spectrum if dark energy
perturbations are included, however, once incorrectly neglecting the dark
energy perturbations, the difference of the results are sizable.Comment: 4 pages, 3 figures, 2 table
Quantitative trait locus (QTL) mapping for 100-kernel weight of maize (Zea mays L.) under different nitrogen regimes
100-kernel weight (KW) is one of the most important agronomic traits in maize (Zea mays L.), related to yield. To realize its genetic basis, in this study, a recombinant inbred line (RIL) population derived from the cross between Mo17 and Huangzao4 was used for quantitative trait locus (QTL) mapping for KW under high and low nitrogen (N) regimes. As a result, five QTLs were identified on chromosomes 3, 4, 7 and 9, of which three were detected under both N environments, while the other two QTLs were respectively detected under high and low N regimes. These QTLs could explain phenotypic variance rom 4.47 to 14.47%. Due to additive effects, the three QTLs from Mo17, including two on chromosome 3 and one on chromosome 4, could increase KW from 0.64 to 1.01 g, while the other two from Huangzao4 on chromosomes 7 and 9 could decrease KW from 0.62 to 1.07 g. These results are beneficial for understanding the genetic basis of KW and developing the markers linked with KW for marker-assisted selection breeding in maize.Key words: Maize (Zea mays L.), 100-kernel weight, quantitative trait locus (QTL), recombinant inbred line (RIL), nitrogen regime
Optical Second Harmonic Generation in Anisotropic Multilayers with Complete Multireflection Analysis of Linear and Nonlinear Waves using #SHAARP.ml Package
Optical second harmonic generation (SHG) is a nonlinear optical effect widely
used for nonlinear optical microscopy and laser frequency conversion.
Closed-form analytical solution of the nonlinear optical responses is essential
for evaluating the optical responses of new materials whose optical properties
are unknown a priori. A recent open-source code, SHAARP(si), can provide such
closed form solutions for crystals with arbitrary symmetries, orientations, and
anisotropic properties at a single interface. However, optical components are
often in the form of slabs, thin films on substrates, and multilayer
heterostructures with multiple reflections of both the fundamental and up to
ten different SHG waves at each interface, adding significant complexity. Many
approximations have therefore been employed in the existing analytical
approaches, such as slowly varying approximation, weak reflection of the
nonlinear polarization, transparent medium, high crystallographic symmetry,
Kleinman symmetry, easy crystal orientation along a high-symmetry direction,
phase matching conditions and negligible interference among nonlinear waves,
which may lead to large errors in the reported material properties. To avoid
these approximations, we have developed an open-source package named Second
Harmonic Analysis of Anisotropic Rotational Polarimetry in Multilayers
(SHAARP(ml)). The reliability and accuracy are established by experimentally
benchmarking with both the SHG polarimetry and Maker fringes predicted from the
package using standard materials
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Revealing of the Activation Pathway and Cathode Electrolyte Interphase Evolution of Li-Rich 0.5Li2MnO3·0.5LiNi0.3Co0.3Mn0.4O2 Cathode by in Situ Electrochemical Quartz Crystal Microbalance.
The first-cycle behavior of layered Li-rich oxides, including Li2MnO3 activation and cathode electrolyte interphase (CEI) formation, significantly influences their electrochemical performance. However, the Li2MnO3 activation pathway and the CEI formation process are still controversial. Here, the first-cycle properties of xLi2MnO3·(1- x) LiNi0.3Co0.3Mn0.4O2 ( x = 0, 0.5, 1) cathode materials were studied with an in situ electrochemical quartz crystal microbalance (EQCM). The results demonstrate that a synergistic effect between the layered Li2MnO3 and LiNi0.3Co0.3Mn0.4O2 structures can significantly affect the activation pathway of Li1.2Ni0.12Co0.12Mn0.56O2, leading to an extra-high capacity. It is demonstrated that Li2MnO3 activation in Li-rich materials is dominated by electrochemical decomposition (oxygen redox), which is different from the activation process of pure Li2MnO3 governed by chemical decomposition (Li2O evolution). CEI evolution is closely related to Li+ extraction/insertion. The valence state variation of the metal ions (Ni, Co, Mn) in Li-rich materials can promote CEI formation. This study is of significance for understanding and designing Li-rich cathode-based batteries
Tongolenine C and tongolenine D, two new diterpenoid alkaloids from Delphinium tongolense F.
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Serum Levels of the Inflammatory Cytokines in Patients with Lumbar Radicular Pain Due to Disc Herniation
Study DesignCohort study.PurposeThis study primarily aimed to evaluate the serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-4 in patients with lumbar radiculopathy 1 and 12 months after microdiscectomy.Overview of LiteratureLumbar radiculopathy is possibly caused by inflammatory changes in the nerve root. The intraneural application of pro-inflammatory cytokines induces behavioral signs associated with pain. Anti-inflammatory cytokine treatment effectively reduces hyperalgesia.MethodsThe role of TNF-α and IL-4 in long-lasting lumbar radiculopathy was addressed. A total of 262 patients were recruited from Anqing Hospital, Anhui Medical University. During inclusion at 1 and 12 months, serum concentrations of TNF-α and IL-4 were analyzed by enzyme-linked immunosorbent assay, and pain intensity was reported on a 0–10 cm visual analog scale (VAS).ResultsSixty six patients had VAS <3 and 196 patients had VAS ≥3. Serum concentrations of pro-inflammatory TNF-α and anti-inflammatory IL-4 in patients with lumbar radiculopathy related to disc herniation were measured at 1- and 12-month follow-up. TNF-α decreased in both VAS groups with time. In contrast, IL-4 increased in both groups at 1 month and then decreased gradually until month 12. The changes in serum levels of TNF-α and IL-4 over time between the VAS ≥3 and VAS <3 groups were significantly different.ConclusionsChronic lumbar radiculopathy may be associated with high level of pro-inflammatory substances, such as TNF-α, in serum after disc herniation, and elevated anti-inflammatory cytokine in patients with lumbar radiculopathy may indicate a favorable outcome
High-Brightness and Color-Tunable FAPbBr(3) Perovskite Nanocrystals 2.0 Enable Ultrapure Green Luminescence for Achieving Recommendation 2020 Displays
To best catch human eyes in next-generation displays, the updated recommendation 2020 (Rec. 2020) standard has called for ultrapure green emitters to be qualified with a narrow emission of 525-535 nm with a full width at half-maximum (fwhm) below 25 nm. However, it is still challenging to find an emitter which can simultaneously cover these two criteria. Instead of traditional II-VI group semiconductor quantum dots, perovskite nanocrystals (NCs) can render versatile emitting tunability to allow them access to the Rec. 2020 standard. Herein, to realize the critical window of Rec. 2020, we have proposed a scalable, room temperature synthesis route of formamidinium lead bromide (FAPbBr3) NCs using a sole ligand of sulfobetaine-18 (SBE-18). The as-synthesized FAPbBr3 NCs exhibit an ideal emission at 534 nm with an ultranarrow fwhm of 20.5 nm and a high photoluminescence quantum yield of 90.6%, overwhelming the FAPbBr3 nanoplates capped with oleic acid/oleylamine (OA/OAM). Introducing these high quality NCs into backlight displays, an ultrapure green backlight which covers ≈85.7% of the Rec. 2020 standard in the CIE 1931 color space is achieved, signifying the "greenest" backlight till now. Thus, we can foresee perovskite NCs as the most potential candidates for next-generation displays
Probing Primordial Gravitational Waves: Ali CMB Polarization Telescope
In this paper, we will give a general introduction to the project of Ali CMB
Polarization Telescope (AliCPT), which is a Sino-US joint project led by the
Institute of High Energy Physics (IHEP) and has involved many different
institutes in China. It is the first ground-based Cosmic Microwave Background
(CMB) polarization experiment in China and an integral part of China's
Gravitational Waves Program. The main scientific goal of AliCPT project is to
probe the primordial gravitational waves (PGWs) originated from the very early
Universe.
The AliCPT project includes two stages. The first stage referred to as
AliCPT-1, is to build a telescope in the Ali region of Tibet with an altitude
of 5,250 meters. Once completed, it will be the worldwide highest ground-based
CMB observatory and open a new window for probing PGWs in northern hemisphere.
AliCPT-1 telescope is designed to have about 7,000 TES detectors at 90GHz and
150GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with
the number of detectors more than 20,000.
Our simulations show that AliCPT will improve the current constraint on the
tensor-to-scalar ratio by one order of magnitude with 3 years' observation.
Besides the PGWs, the AliCPT will also enable a precise measurement on the CMB
rotation angle and provide a precise test on the CPT symmetry. We show 3 years'
observation will improve the current limit by two order of magnitude.Comment: 11 pages, 7 figures, 2 table
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