Genome-Wide Association Study of Cooked Rice Textural Attributes and Starch Physicochemical Properties in indica Rice

Rice cooking and eating qualities(CEQ)are mainly determined by cooked rice textural parameters and starch physicochemical properties.However,the genetic bases of grain texture and starch properties in rice have not been fully understood.We conducted a genome-wide association study for apparent amylose content(AAC),starch pasting viscosities,and cooked rice textural parameters using 279 indica rice accessions from the 3000 Rice Genome Project.We identified 26 QTLs in the whole population and detected single nucleotide polymorphisms(SNPs)with the lowest P-value at the Waxy(Wx)locus for all traits except pasting temperature and cohesiveness.Additionally,we detected significant SNPs at the SUBSTANDARD STARCH GRAIN6(SSG6)locus for AAC,setback(SB),hardness,adhesiveness,chewiness(CHEW),gumminess(GUM),and resilience.We subsequently divided the population using a SNP adjacent to the Waxy locus,and identified 23 QTLs and 12 QTLs in two sub-panels,WxT and WxA,respectively.In these sub-panels,SSG6 was also identified to be associated with pasting parameters,including peak viscosity,hot paste viscosity,cold paste viscosity,and consistency viscosity.Furthermore,a candidate gene encoding monosaccharide transporter 5(OsMST5)was identified to be associated with AAC,breakdown,SB,CHEW,and GUM.In total,39 QTLs were co-localized with known genes or previously reported QTLs.These identified genes and QTLs provide valuable information for genetic manipulation to improve rice CEQ.

Two-Body Hadronic Weak Decays of Bottomed Hadrons

The structure of light diquarks plays a crucial role in formation of exotic hadrons beyond the conventional quark model, especially with regard to the line shapes of bottomed hadron decays. We study the two-body hadronic weak decays of bottomed baryons and bottomed mesons to probe the light diquark structure and to pin down the quark–quark correlations in the diquark picture. It is found that the light diquark does not favor a compact structure. For instance, the isoscalar diquark [ud] in Λ_(b)^(0) can be easily split and rearranged to form ■via the color-suppressed transition. This provides a hint that the hidden charm pentaquark states produced in Λ_(b)^(0) decays could be the ■chadronic molecular candidates. This quantitative study resolves the apparent conflicts between the production mechanism and the molecular nature of these P_(c) states observed in experiment.

Selected topics of quantum computing for nuclear physics

Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.

Identification of a Reliable DFT Calculation Method to Predict the Ground-and Excited-State Properties of Nickel(Ⅱ) Complexes with Porphyrin in Crude Oil

Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond.

Molecular Nature of X(3872)in B^(0)→K^(0)X(3872)and B^(+)→K^(+)X(3872)Decays

We investigate the decays of B^(0)→K^(0)X(3872)and B^(+)→K^(+)X(3872)based on the picture where the X(3872)resonance is strongly coupled to the DD*+c.c.channel.In addition to the decay mechanism where the X(3872)resonance is formed from the DD*pair hadronization with the short-distance interaction,we have also considered the DD*rescattering diagrams in the long-distance scale,where D andD*are formed from c andDD*separately.Because of the difference of the mass thresholds of charged and neutralDD*channels,and the rather narrow width of the X(3872)resonance,at the X(3872)mass,the loop functions ofD^(0)D*^(0)andD^(+)D*^(-)are much different.Taking this difference into account,the ratio of B[B^(0)→K^(0)X(3872)]/B[B+→K+X(3872)]■0.5 can be naturally obtained.Based on this result,we also evaluate the decay widths of B_s^(0)→η(η′)X(3872).It is expected that future experimental measurements of these decays can be used to elucidate the nature of the X(3872)resonance.

Transference kinetics of ^(60)Co in an aquatic-terrestrial ecosystem

The dynamics of transportation,accumulation,disappearance and distribution of 60Co in a simulated aquatic-terrestrial ecosystem was studied by isotope-tracer technique. In the aquatic system,60Co was transported and transformed via depositing,coupling with ions and adsorption. The absorption resulted in the redistribution and accumulation of 60Co in each compartment of the system. Specific activities of 60Co in water started sharply and gently decreased. The sediment accumulated a large amount of 60Co by adsorption and ion exchange. The hornwort (Ceralophyllum demersum) could also adsorb a large amount of 60Co in a short time,because of its large specific surface area. Fish (Carassius auratus) and snail (Bellamya purificata) had a poor capacity of adsorbing 60Co. The distribution of 60Co in the fish was mainly in the viscera,and the amount of 60Co in the snail flesh was greater than that in the shell. The amount of 60Co in individual compartment in the system was changed with time. The highest specific activity of 60Co in the bean of the terrestrial system remained in the root nodule.

Progress in the R&D Experiments About a Novel Method of Electr Scattering off Short-lived Nuclei

A novel method has been established to realize the experiment of electron scattering off short-lived nuclei. The method was based on the well known ＂ion trapping＂ phenomenon in electron storage rings. In the R^D experiments at Kyoto University, stable nucleus, 133^Cs, was employed as the target nucleus. The luminosity of scattering experiment was nearly 1026 cm^-2s^-1 at electron beam current around 75 mA. The angular distribution of elastically scattered electrons from trapped Cs ions was measured and the result was well fitted by theoretical calculation. It was indicated that higher luminosity can be reached with larger electron beam current.

Phenomenological study of the anisotropic quark matter in the two-flavor Nambu–Jona–Lasinio model

With the two-flavor Nambu–Jona–Lasinio (NJL) model, we carried out a phenomenological study on the chiral phase structure, mesonic properties, and transport properties of momentum-space anisotropic quark matter. To calculate the transport coefficients we utilized the kinetic theory in the relaxation time approximation, where the momentum anisotropy is embedded in the estimation of both the distribution function and relaxation time. It was shown that an increase in the anisotropy parameterξmay result in a catalysis of chiral symmetry breaking. The critical endpoint(CEP) is shifted to lower temperatures and larger quark chemical potentials asξincreases, and the impact of momentum anisotropy on the CEP temperature is almost the same as that on the quark chemical potential of the CEP. The meson masses and the associated decay widths also exhibit a significant ξ dependence. It was observed that the temperature behavior of the scaled shear viscosity η/T~3 and scaled electrical conductivity σ/T exhibited a similar dip structure, with the minima of both η/T~3 and σ/T shifting toward higher temperatures with increasing ξ. Furthermore,we demonstrated that the Seebeck coefficient S decreases when the temperature rises and its sign is positive, indicating that the dominant carriers for converting the temperature gradient to the electric field are up-quarks. The Seebeck coefficient S is significantly enhanced with a largeξfor a temperature below the critical temperature.

Measurement of D（d,p）T Reaction Cross Sections in Sm Metal in Low Energy Region （10 ≤ Ed ≤20 keV）

To study the screening effect of nuclear reactions in metallic environments, the thick target yields, the cross sections and the experimental S（E） factors of the D（d, p）T reaction have been measured on deuterons implanted in Sm metal at 133.2K for beam energies ranging from 10 to 20 ke V. The thick target yields of protons emitted in the D（d, p）T reaction are measured and compared with those data extrapolated from cross sections and stopping power data at higher energies. The screening potential in Sm metal at 133.2K is deduced to be 520±56eV. As compared with the value achieved in the gas target, the calculated screening potential values are much larger. This screening potential cannot be simply interpreted only by the electron screening. Energy dependences of the cross section σ（E） and the experimental S（E） factor for D（d,p）T reaction in Sm metal at 133.2K are obtained, respectively.

Probing granular inhomogeneity of a particle-emitting source by imaging two-pion Bose–Einstein correlations

Using the source imaging technique in two-pion interferometry,we study the image of the hydrodynamic particle-emitting source with the HIJING initial conditions for relativistic heavy-ion collisions on an event-by-event basis.It is shown that the initial-state fluctuations may give rise to bumpy structures of the medium during hydrodynamical evolution,which affects the two-pion emission space and leads to a visible two-tiered shape in the source function imaged using the two-pion Bose–Einstein correlations.This two-tiered shape can be understood within a similar but more analytic granular source model and is found to be closely related to the introduced quantity n,which characterizes the granular inhomogeneity of the source.By fitting the imaged source function with a granular source parametrization,we extract the granular inhomogeneity of the hydrodynamic source,which is found to be sensitive to both the Gaussian smearing width of the HIJING initial condition and the centrality of the collisions.

Characterizing entanglement in non-Hermitian chaotic systems via out-of-time ordered correlators

We investigate the quantum entanglement in a non-Hermitian kicking system.In the Hermitian case,the out-of-time ordered correlators(OTOCs)exhibit the unbounded power-law increase with time.Correspondingly,the linear entropy,which is a common measurement of entanglement,rapidly increases from zero to almost unity,indicating the formation of quantum entanglement.For strong enough non-Hermitian driving,both the OTOCs and linear entropy rapidly saturate as time evolves.Interestingly,with the increase of non-Hermitian kicking strength,the long-time averaged value of both OTOCs and linear entropy has the same transition point where they exhibit the sharp decrease from a plateau,demonstrating the disentanglment.We reveal the mechanism of disentanglement with the extension of Floquet theory to non-Hermitian systems.

Identification of New Allele of FLOURY ENDOSPERM2 in White-Core Endosperm Mutant of Rice

Identification of regulatory genes from chalky/floury endosperm mutants is an important approach to understand the mechanism of starch biosynthesis to accelerate rice grain quality improvement.A mutant GM645,identified from 60Coγ-irradiation of an indica rice Guanglu’ai 4(GLA4),exhibited white-core endosperm and altered starch physicochemical properties.However,the causal gene responsible for the white-core endosperm in GM645 has not been identified.Here,we developed a recombined inbred line(RIL,F7)population derived from a cross between GM645 and a japonica rice Tainong 67(TN67)with translucent endosperm.Bulkedsegregant analysis combined with next generation sequencing revealed five single nucleotide polymorphisms(SNPs)in four candidate genes that were highly associated with the white-core endosperm.Among them,one base pair deletion in Os04g0645100 resulted in a frame shift mutation after the 983th amino acid(aa),and a premature stop codon occurred after the other 11 aa.Moreover,functional annotation revealed that Os04g0645100 was previously characterized as the FLOURY ENDOSPERM2(FLO2)gene.Full-length coding sequence from Os04g0645100 driven by the maize ubiquitin promoter was transformed into GM645,and seeds from these transgenic plants expressing Os04g0645100 were largely rescued to translucent,indicating that Os04g0645100 was responsible for the whitecore endosperm in GM645.

Transference Kinetics of Radionuclide ⁹⁵Nb in the Aquatic Ecosystem

The dynamics of transportation, accumulation, diminishment and distribution of 95Nb in a simulated aquatic ecosystem was studied using the isotope-tracer technique, and a fitting equation was established by application of a closed, five-compartment model. The results showed that when 95Nb was introduced into an aquatic system, it was transported and transformed via deposition in combination with other ions, and adsorption and absorption by aquatic organisms, resulting in redistribution and accumulation in different parts of the organisms. Following addition, the spe- cific activity of 95Nb in water decreased sharply within a short time, and then after reaching a certain value, it decreased more slowly. Sediment accumulated large amounts of 95Nb through the exchange of ions. Hyacinth (Eichhornia crassipes) also adsorbed a large amount of 95Nb in a short period of time. Snails (Bellamya purificata) and fish (Carassius auratus) were found to have a poor adsorption capacity of 95Nb. The amount of 95Nb found in the snail flesh was greater than that in the shell, and the 95Nb found in the fish was mainly distributed in the viscera. The amount of 95Nb in each individual component of the experimental system was affected over time.

Jet Radius and Momentum Splitting Fraction with Dynamical Grooming in Heavy-Ion Collisions

We investigate the medium modifications of momentum splitting fraction and groomed jet radius with both dynamical grooming and soft drop algorithms in heavy-ion collisions.In the calculation,the partonic spectrum of initial hard scattering in p+p collisions is provided by the event generator PYTHIA8,and the energy loss of fast parton traversing in a hot/dense quantum-chromodynamic medium is simulated with the linear Boltzmann transport model.We predict the normalized distributions of the groomed jet radiusθ_(g)and momentum splitting fraction z_(g)with the dynamical grooming algorithm in Pb+Pb collisions at(sNN)~(1/2)=5.02 TeV,then compare these quantities in dynamical grooming at a=0.1,with that in soft drop at z_(out)=0.1 andβ=0.It is found that the normalized distribution ratios Pb+Pb/p+p with respect to z_(g)in z_(cut)=0.1,β=0 soft drop case are close to unity,those in a=0.1 dynamical grooming case show enhancement at small z_(g),and Pb+Pb/p+p with respect toθ_(g)in the dynamical grooming case demonstrate weaker modification than those in the soft drop counterparts.We further calculate the groomed jet number averaged momentum splitting fraction_(jets)and averaged groomed jet radius<θ_(g)>_(jets)in p+p and A+A for both grooming cases in three p_T~(ch jet)intervals,and find that the originally generated well balanced groomed jets will become more momentum imbalanced and jet size less narrowed due to jet quenching,and weaker medium modification of z_(g)andθ_(g)in the a=0.1 dynamical grooming case than in the soft drop counterparts.

Approach the Gell-Mann–Okubo Formula with Machine Learning

Machine learning is a novel and powerful technology and has been widely used in various science topics.We demonstrate a machine-learning-based approach built by a set of general metrics and rules inspired by physics.Taking advantages of physical constraints,such as dimension identity,symmetry and generalization,we succeed to approach the Gell-Mann-Okubo formula using a technique of symbolic regression.This approach can effectively find explicit solutions among user-defined observables,and can be extensively applied to studying exotic hadron spectrum.

Radial profile of bottom quarks in jets in high-energy nuclear collisions

Angular correlations between a heavy quark(HQ)and its tagged jet are potentially new tools to gain insight into the in-medium partonic interactions in relativistic heavy-ion collisions.In this work,we present the first theoretical study on the radial profiles of B mesons in jets in Pb+Pb collisions at the Large Hadron Collider(LHC).The initial production of a bottom quark tagged jet in p+p is computed by SHERPA,which matches the next-to-leading order matrix elements with contributions of parton showers,whereas the massive quark traversing the quark-gluon plasma is described by a Monte Carlo model,SHELL,which can simultaneously simulate light and heavy flavor in-medium energy loss within the framework of Langevin evolution.In p+p collisions,we find that at lower PQ/T the radial profiles of heavy flavors in jets are sensitive to the heavy quark mass.In 0-10%Pb+Pb collisions at√SNN=5.02 TeV,we observe an inverse modification pattern of the B meson radial profiles in jets at4PQ/T<20 GeV compared to those of D mesons:the jet quenching effects narrow the jet radial profiles of B mesons in jets while broadening those of D mesons in jets.We find that in A+A collisions,the contribution dissipated from the higher PQ/T>20 GeV region naturally has a narrower initial distribution and consequently leads to a narrower modification pattern of the radial profile;however the diffusion nature of the heavy flavor in-medium interactions will give rise to a broader modification pattern of the radial profile.These two effects consequently compete and offset with each other,and the b quarks in jets benefit more from the former and suffer less diffusion effect compared to that of c quarks in jets.These findings can be tested in the future experimental measurements at the LHC to gain better understanding of the mass effect of jet quenching.

p_(T) dispersion of inclusive jets in high-energy nuclear collisions

In this study,we investigate the impact of jet quenching on the p_(T) dispersion(p_(T)D)of inclusive jets(R=0.2)in central Pb+Pb(0%-10%)collisions at √s=2.76 TeV.The partonic spectrum in the initial hard scattering of elementary collisions is obtained by an event generator POWHEG+PYTHIA,which matches the next-to-leading order(NLO)matrix elements with parton showering,and the energy loss of a fast parton traversing through hot/dense QCD medium is calculated using Monte Carlo simulation within the Higher-Twist formalism of jet quenching in heavy-ion collisions.We present model calculations of the normalized p_(T)D distributions of inclusive jets in p+p and central Pb+Pb collisions at √s=2.76 TeV,which offer good descriptions of ALICE measurements.It is shown that the p_(T)D distributions of inclusive jets in central Pb+Pb collisions shift significantly to a higher p_(T)D region relative to those in p+p collisions.Thus,the nuclear modification ratio of the p_(T)D distributions of inclusive jets is smaller than unity in the small p_(T)D region and larger than one in the large p_(T)D region.This behavior is caused by a more uneven p_(T) distribution for jet constituents as well as the fraction alteration of quark/gluon initiated jets in heavy-ion collisions.The difference in p_(T)D distribution between groomed and ungroomed jets in Pb+Pb collisions is also discussed.

Exploring J/ψ Production Mechanism at the Future Electron-Ion Collider

We propose to use transverse momentum pT distribution of J/ψ production at the future Electron Ion Collider(EIC)to explore the production mechanism of heavy quarkonia in high energy collisions.We apply QCD and QED collinear factorization to the production of a cc pair at high pT,and non-relativistic QCD factorization to the hadronization of the pair to a J/ψ.We evaluate J/ψ pT-distribution at both leading and next-to-leading order in strong coupling,and show that production rates for various color-spin channels of a cc pair in electronhadron collisions are very different from that in hadron-hadron collisions,which provides a strong discriminative power to determine various transition rates for the pair to become a J/ψ.We predict that the J/ψproduced in electron-hadron collisions is likely unpolarized,and the production is an ideal probe for gluon distribution of colliding hadron(or nucleus).We find that the J/ψ production is dominated by the color-octet channel,providing an excellent probe to explore the gluon medium in large nuclei at the EIC.

A fast emittance measurement unit for high intensity DC beam

A combined unit, which has the ability to measure the current and emittance of the high intensity direct current（DC）ion beam, is developed at Peking University（PKU）. It is a multi-slit single-wire（MSSW）-type beam emittance meter combined with a water-cooled Faraday Cup, named high intensity beam emittance measurement unit-6（HIBEMU-6）. It takes about 15 seconds to complete one measurement of the beam current and its emittance. The emittance of a 50-mA@50-kV DC proton beam is measured.

Z^(0)boson associated b-jet production in high-energy nuclear collisions

The production of vector boson tagged heavy quark jets potentially provides new tools to probe the jet quenching effect.In this paper,we present the first theoretical study on the angular correlations(ΔφbZ),transverse momentum imbalance(xbZ),and nuclear modification factor(IAA) of Z0boson tagged b-jets in heavy-ion collisions,which was performed using a Monte Carlo transport model.We find that the medium modification of theΔφbZfor Z0+b-jet has a weaker dependence on ΔφbZthan that for Z^(0)+jet,and the modification patterns are sensitive to the initial jet pTdistribution.Additionally,with the high purity of the quark jet in Z^(0)+(b-) jet production,we calculate the momentum imbalance xbZand the nuclear modification factor IAAof Z^(0)+b-jet in Pb+Pb collisions.We observe a smaller Δ<xjZ> and larger IAAof Z^(0)+b-jet in Pb+Pb collisions relative to those of Z^(0)+jet,which may be an indication of the mass effect of jet quenching and can be tested in future measurements.