Saturation Scale Research Articles

Discovery of genes that positively affect biomass and stress associated traits in poplar.

Woody biomass serves as a renewable resource for various industries, including pulp and paper production, construction, biofuels, and electricity generation. However, the molecular mechanisms behind biomass traits are poorly understood, which significantly curtails the speed and efficiency of their improvement. We used activation tagging to discover genes that can positively affect tree biomass-associated traits. We generated and screened under greenhouse conditions a population of 2,700 independent activation tagging lines. A total of 761 lines, which had significantly and positively affected at least one biomass-associated trait, were discovered. The tag was positioned in the genome for forty lines which were affected in multiple traits and activation of proximal genes validated for a subset. For two lines we fully recapitulated the phenotype of the original lines through overexpression. Moreover, the overexpression led to more pronounced and additional improvements, not observed in the original lines. Importantly, the overexpression of a Fasciclin-like gene (PtaFLA10) and a Patatin-like gene (PtaPAT) was found to substantially improve biomass, with a 40% increase in dry-stem weight, and enhance drought tolerance, respectively. Additionally, PtaPAT overexpression increased cellulose content, which is crucial for biofuel production. Our work shows that the activation tagging approach applied even on a non-genome saturation scale in a poplar tree can be successfully used for the discovery of genes positively modify biomass productivity. Such dominant forward genetics approaches can aid in biotechnological manipulation of woody biomass traits and help unravel the functions and mechanisms of individual genes, gene families, and regulatory modules.

Incoherent diffractive production of jets in electron DIS off nuclei at high energy

We study incoherent diffractive production of two and three jets in electron-nucleus deep inelastic scattering (DIS) at small xBj using the color dipole picture and the effective theory of the color glass condensate (CGC). We consider color fluctuations in the CGC weight-function as the source of the nuclear break-up and the associated momentum transfer |t|. We focus on the regime in which the two jets are almost back-to-back in transverse space and have transverse momenta P⊥ much larger than both the momentum transfer and the saturation scale Qs. The cross section for producing such a hard dijet is parametrically dominated by large size fluctuations in the projectile wave-function that scatter strongly and for which a third, semihard, jet appears in the final state. The 2+1 jets cross section can be written in a factorized form in terms of incoherent quark and gluon diffractive transverse momentum distributions (DTMDs) when the third jet is explicit, or incoherent diffractive parton distribution functions (DPDFs) when the third jet is integrated over. We find that the DPDFs and the corresponding cross section saturate logarithmically when |t|≪Qs2, while they fall like 1/|t|2 in the regime Qs2≪|t|≪P⊥2. We further show that there is no angular correlation between the hard jet momentum and the momentum transfer. For typical EIC kinematics the 2 jets and 2+1 jets cross sections are of the same order. Published by the American Physical Society 2024

Evolution of the color dipole cross section

Using Laplace transform techniques, we describe the evolution of the color dipole cross section at the leading-order and next-to-leading-order approximations from the Bartels–Golec-Biernat–Kowalski model in a kinematic region of low values of the Bjorken variable x and a wide range of transverse dipole size r. This evolution method shows that the saturation scale and geometric scaling are retained. We derived analytical results for the integrated and unintegrated color dipole gluon distribution functions and compared them with the CJ15 parameterization group and the unintegrated color dipole gluon distribution models, respectively. The Sudakov form factor in the evolution of the unintegrated color dipole gluon distribution is incorporated, and the results are considered at small and large values of kt2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k_{t}^{2}$$\\end{document}.

Effects of saturation and fluctuating hotspots for flow observables in ultrarelativistic heavy-ion collisions

We investigate the effects of saturation dynamics on midrapidity flow observables by adding fluctuating hotspots into the novel Monte Carlo EKRT (MC-EKRT) event generator for high-energy nuclear collisions. We demonstrate that the intensity of the saturation effects significantly affects the ratio between the flow coefficients v3 and v2 at the LHC. Adding a hotspot substructure to the nucleons enhances the saturation effects and improves the agreement with the measured data. We show that the collision-energy dependence of the flow coefficients obtained using the MC-EKRT initial states with hotspots is improved in comparison with the earlier event-by-event EKRT model. In addition, we present the results for the charged hadron multiplicity distribution in Pb+Pb collisions at the LHC, and show that the minijet multiplicity originating fluctuations of the saturation scale included in MC-EKRT, as well as the presence of hotspots, are necessary for describing the measured large-multiplicity tail in the distribution. Published by the American Physical Society 2024

Multiplicity dependence of the pT -spectra for identified particles and its relationship with partonic entropy

We investigate the multiplicity dependence of the transverse momentum pT spectra of hadrons produced in high-energy collisions. We propose that the partonic distribution be parametrized by its nonextensive entropy and the parton saturation scale Qs(x). These two variables can be identified from the produced charged hadron distributions and provide important information on the gluon dynamics at the moment of interaction. From this perspective, we interpret data from different ALICE multiplicity classes at s=13 TeV and s=5.02 TeV. A multiplicity-dependent scaling function is presented and the dependence of the interaction area on multiplicity is also investigated. Published by the American Physical Society 2024

Power counting to saturation

We present a description of saturation in small x deep inelastic scattering from power counting in a top-down effective theory derived from quantum chromodynamics (QCD). A factorization formula isolates the universal physics of the nucleus at leading power in x. The onset of saturation is then understood as a breakdown in the expansion in an emergent power counting parameter, which is defined by the matrix element of a gauge invariant operator. We identify a new radiation mode, which enables us to extend previous literature by distinguishing the appearance of the saturation scale from the transition to nonlinear evolution. Published by the American Physical Society 2024

Next-to-eikonal corrections to dijet production in Deep Inelastic Scattering in the dilute limit of the Color Glass Condensate

We analyze the effects of next-to-eikonal corrections on dijet production in Deep Inelastic Scattering off nuclear targets in the framework of the Color Glass Condensate. They require the knowledge of correlators of fields in the target beyond those computed in the standard McLerran-Venugopalan model, specifically those between transverse and boost-enhanced components, and of the recoil of the fields. We neglect the latter, while for the former we develop a linear model valid for large nuclei. We considered the unpolarized cross sections for dijet production in the approximation of a homogenous dilute nucleus, obtaining simple analytic expressions for the cross sections at next-to-eikonal accuracy, valid in the limit of total dijet momentum and dijet momentum imbalance larger than the saturation scale of the nucleus. We perform a numerical study of the results at energies of the Electron Ion Collider, finding O\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O} $$\\end{document}(10%) effects in the cross sections at large total momentum. We also analyze the azimuthal asymmetries between total momentum and imbalance, finding that non-eikonal corrections induce odd azimuthal harmonics for the situation of jets with equal momentum fractions from the virtual photon, where they are absent in the eikonal approximation. Finally, in the eikonal approximation we have compared the results of our analytic expansion valid in the dilute limit of the target, and the full Color Glass Condensate results in the McLerran-Venugopalan model and their correlation limit. Our analytic expressions match the correlation limit ones in the region where both should be simultaneously valid and reproduce very well the full Color Glass Condensate results in its validity region.

SurvdigitizeR: an algorithm for automated survival curve digitization

BackgroundDecision analytic models and meta-analyses often rely on survival probabilities that are digitized from published Kaplan–Meier (KM) curves. However, manually extracting these probabilities from KM curves is time-consuming, expensive, and error-prone. We developed an efficient and accurate algorithm that automates extraction of survival probabilities from KM curves.MethodsThe automated digitization algorithm processes images from a JPG or PNG format, converts them in their hue, saturation, and lightness scale and uses optical character recognition to detect axis location and labels. It also uses a k-medoids clustering algorithm to separate multiple overlapping curves on the same figure. To validate performance, we generated survival plots form random time-to-event data from a sample size of 25, 50, 150, and 250, 1000 individuals split into 1,2, or 3 treatment arms. We assumed an exponential distribution and applied random censoring. We compared automated digitization and manual digitization performed by well-trained researchers. We calculated the root mean squared error (RMSE) at 100-time points for both methods. The algorithm’s performance was also evaluated by Bland–Altman analysis for the agreement between automated and manual digitization on a real-world set of published KM curves.ResultsThe automated digitizer accurately identified survival probabilities over time in the simulated KM curves. The average RMSE for automated digitization was 0.012, while manual digitization had an average RMSE of 0.014. Its performance was negatively correlated with the number of curves in a figure and the presence of censoring markers. In real-world scenarios, automated digitization and manual digitization showed very close agreement.ConclusionsThe algorithm streamlines the digitization process and requires minimal user input. It effectively digitized KM curves in simulated and real-world scenarios, demonstrating accuracy comparable to conventional manual digitization. The algorithm has been developed as an open-source R package and as a Shiny application and is available on GitHub: https://github.com/Pechli-Lab/SurvdigitizeR and https://pechlilab.shinyapps.io/SurvdigitizeR/.

The effects of smoking on pain scores, vital signs, and analgesic consumption in patients undergoing tympanomastoidectomy surgery.

In this study, we investigate the effects of smoking on pain scores, vital signs, and analgesic consumption in the intraoperative and postoperative period in patients undergoing tympanomastoidectomy surgery. A total of 100 patients with American Society of Anesthesiologists I-II status, aged 18-55 years, and who were planned to undergo tympanomastoidectomy surgery were divided into two groups: smokers (Group 1) and non-smokers (Group 2). The patients were compared for preoperative, intraoperative, and 24-hour postoperative carboxyhemoglobin, blood pressure, oxygen saturation, respiratory rate, heart rate, pain intensity and verbal numerical rating scales, the extent of patient-controlled tramadol dose, nausea, and vomiting. There were 50 individuals in each group. Postoperative analgesic consumption and pain scores were higher in Group 1, and the first postoperative pain was felt earlier. Furthermore, in Group 1, preoperative carboxyhemoglobin levels and postoperative nausea were statistically higher before, after, and at the tenth minute after induction, whereas oxygen saturation was lower. The two groups had no statistical difference regarding intraoperative and postoperative vital signs. Postoperative analgesic consumption was not affected by age or gender. Smoking changes postoperative pain management, especially for this kind of operation, and these patients feel more pain and need more postoperative analgesic doses. Therefore, effective postoperative pain control should take account of smoking behavior, and analgesic doses may need to be adjusted for patients who smoke.

D0 meson production in pp collisions at large Qs2

The impact of the nonlinear effects in the QCD on the observables is directly related to the magnitude of the saturation scale Qs, which is predicted to increase with the energy, rapidity, and multiplicity. In this paper, we investigate the D0 meson production in pp collisions at forward rapidities and/or high multiplicities considering the color glass condensate (CGC) formalism and the solutions of the running coupling Balitsky-Kovchegov equation. The contributions of gluon- and charm-initiated processes are taken into account, and a comparison with the current LHCb data is performed. The impact of an intrinsic charm component in the proton’s wave function is also estimated. Predictions for the self-normalized yields of D0 mesons as a function of the multiplicity of coproduced charged hadrons are presented, considering pp collisions at s=13 TeV and different values of the meson rapidity. A comparison with the predictions for the kaon and isolated photon production is performed. Our results indicate that a future experimental analysis of the D0 meson production at forward rapidities and high multiplicities can be useful to probe the CGC formalism and to disentangle the contribution of initial—and final—state effects. Published by the American Physical Society 2024

Proton PDFs with nonlinear corrections from gluon recombination

We present numerical studies of the leading nonlinear corrections to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations of parton distribution functions (PDFs) resulting from gluon recombination. The effect of these corrections is to reduce the pace of evolution at small momentum fractions x while slightly increasing it at intermediate x. By implementing the nonlinear evolution in the framework, we have carried out fits of proton PDFs using data on lepton-proton deep inelastic scattering from HERA, BCDMS, and NMC. While we find no evidence for the presence of nonlinearities, they cannot be entirely excluded either, and we are able to set limits for their strength. In terms of the recombination scale Qr, which plays a similar role as the saturation scale in the dipole picture of the proton, we find that Qr≲2.5 GeV. We also quantify the impact of the nonlinear terms for the longitudinal structure function at the Electron-Ion Collider and the Large Hadron Electron Collider and find that these measurements could provide stronger constraints on the projected effects. Published by the American Physical Society 2024

Microscale Mechanical Behaviour Evaluation of Unsaturated Granular Soils via 4D in situ Triaxial Test on μ-CT

Owing to the complex structure and stress history of unsaturated soils, the micro-mechanism of effective stress theory in unsaturated soil mechanics remains unelucidated. In this study, we developed a miniature triaxial test apparatus for a micro-focus computed tomography (μ-CT) scanning system for the microscopic study of the mechanical behaviour of unsaturated soil. By comparing the results from the developed mini-triaxial test device system with those from a conventional triaxial device, its experimental accuracy was verified. Micron-level high-resolution CT images of sheared specimens at different strain stages were obtained using the device for in situ suction-control triaxial compression 4D (3-Dimensional+Dynamic) tests with a μ-CT scanning system. The multiscale evolution behaviours of the physical parameters (porosity and degree of saturation) of the specimens corresponded to the stress–strain relationship revealed by the in situ test. Triaxial shearing drains out the pore water, and the decomposition of the largest water clusters causes the quantity of small-volume liquid clusters to increase, shifting the distribution of the interfacial areas. The degree of saturation scale indicates the presence of liquid bridges within the shear band that provide interparticle cementation effect and thus enhance the global strength of unsaturated granular soil specimens.

Hydrodynamization in hybrid Bjorken flow attractors

Hybrid fluid models, consisting of two sectors with more weakly and more strongly self-interacting degrees of freedom coupled consistently as in the semi-holographic framework, have been shown to exhibit an attractor surface for Bjorken flow. Retaining only the simple viscid fluid descriptions of both sectors, we find that, on the attractor surface, the hydrodynamization times of both subsectors decrease with increasing total energy density at the respective point of hydrodynamization following a conformal scaling, reach their minimum values, and subsequently rise rapidly. The minimum values are obtained when the respective energy densities are of the order of the inverse of the dimensionful inter-system coupling. Restricting to attractor curves which can be matched to glasma models at a time set by the saturation scale for both p-p and Pb-Pb collisions, we find that the more weakly coupled sector hydrodynamizes much later, and the strongly coupled sector hydrodynamizes earlier in p-p collisions, since the total energy densities at the respective hydrodynamization times of these sectors fall inside and outside of the conformal window. This holds true also for phenomenologically relevant solutions that are significantly away from the attractor surface at the time we match to glasma models.

Parallel scattering, saturation, and generalized Abramovskii-Gribov-Kancheli (AGK) theorem in the EPOS4 framework, with applications for heavy-ion collisions at sNN of 5.02 TeV and 200 GeV

Ultrarelativistic heavy-ion collisions will first realize many nucleon-nucleon scatterings, happening instantaneously and therefore necessarily in parallel, due to the short collision time. An appropriate quantum mechanical tool to treat that problem is S-matrix theory, and it has been known for a long time how to derive a simple geometric probabilistic picture, still widely used, and here the Abramovskii-Gribov-Kancheli (AGK) theorem plays a crucial role. All this is done in a scenario where energy conservation is not taken care of, but this is needed, in particular for Monte Carlo simulations. When introducing energy-momentum sharing properly, the AGK theorem does not apply anymore, nor do simple geometric concepts such as binary scaling. I will discuss this (very serious) problem, and how it can be solved, in the EPOS4 framework. When connecting the multiple-Pomeron approach (for parallel scatterings) and perturbative QCD, one is actually forced to implement in a very particular way saturation scales in order to get an approach free of contradictions. One recovers a generalized AGK theorem (gAGK), valid at large pt (larger than the relevant saturation scales). I discuss how gAGK is related to factorization (in proton-proton scatterings) and binary scaling (in heavy-ion collisions). I will show some applications, using this new approach as an initial condition for hydrodynamical evolutions, for heavy-ion collisions at sNN of 5.02 TeV and 200 GeV, to get some idea about the energy dependence. Published by the American Physical Society 2024

Particle Production in pA Collisions at Mid-Rapidity in the Color Glass Condensate

Particle correlations in small collisions systems, like proton–nucleus, lie at the core of the discussion about whether quark–gluon plasma is produced in small systems. Both initial and final state explanations have been essayed to describe such correlations. In this work, we focus on the initial state explanations provided by the quantum effects in the initial wave function of the incoming hadrons, in the framework of the Color Glass Condensate effective theory. We describe the formalism indicating the different inputs required for phenomenological applications. We compare the results from two different models, finding that the results for azimuthal harmonics agree qualitatively, but show quantitative differences, particularly at transverse momenta above the saturation scale.

Forward dijet production at the LHC within an impact parameter dependent TMD approach

We investigate possible signatures of gluon saturation using forward p + A → j + j + X di-jet production processes at the Large Hadron Collider. In the forward rapidity region, this is a highly asymmetric process where partons with large longitudinal momentum fraction x in the dilute projectile are used as a probe to resolve the small x partonic content of the dense target. Such dilute-dense processes can be described in the factorization framework of Improved Transverse Momentum Distributions (ITMDs). We present a new model for ITMDs where we explicitly introduce the impact parameter (b) dependence in the ITMDs, to properly account for the nuclear enhancement of gluon saturation effects, and discuss the phenomenological consequences for p − Pb, p − Xe and p − O collisions at the LHC. While the case of p − p and e − p collisions is used to fix the model parameters, we find that, on average, the nuclear enhancement of the saturation scale is noticeably weaker than expected from naive scaling with a simple dependence on the atomic number. Since our model explicitly accounts for event-by-event fluctuations of the nuclear geometry, it can also be applied to study forward central correlations in p − A collisions.

Nuclear modification factor for quarkonium production in high energy proton‐nucleus collisions within the parton saturation approach

AbstractIn this work, we analyze nuclear effects in the inclusive production of quarkonium in proton‐nucleus collisions at high energy regime. A theoretical framework that includes initial state effects like nuclear shadowing and gluon density saturation is considered. Numerical results for nuclear modification factor, , as a function of meson rapidity in proton‐nucleus collisions are presented. The parameter‐free predictions are compared to the available data from the Large Hadron Collider. Discussion on the main theoretical uncertainties is made, with emphasis on the phenomenological models for the nuclear saturation scale.

Forward gamma +jet production in proton-proton and proton-lead collisions at LHC within the FoCal calorimeter acceptance

Using the small-x improved transverse momentum dependent factorization (ITMD), which, for a general two-to-two massless scattering can be proved within the color glass condensate (CGC) theory for transverse momenta of particles greater than the saturation scale, we provide predictions for isolated forward photon and jet production in proton-proton and proton-nucleus collisions within the planned ALICE FoCal detector acceptance. We study azimuthal correlations, p_T spectra, as well as normalized ratios of proton-proton cross sections for different energies. The only TMD distribution needed for that process is the “dipole” TMD gluon distribution, which in our computations is based on HERA data and undergoes momentum space BK evolution equation with DGLAP corrections and Sudakov resummation. We conclude, that the process provides an excellent probe of the dipole TMD gluon distribution in saturation regime.

The Effectiveness of Group Guidance Using Problem Solving Technique to Prevent Learning Saturation of Grade 8B Students in SMP Negeri 4 Yogyakarta

In this study, the objectives achieved by researchers reached the stage of knowing how effective the provision of group guidance services is problem solving techniques to reduce learning saturation. This type of research is quantitative with a pre-experimental method with a one group pretest-posttest design. The population taken in this study was class 8B students, then the research sample was 6 students. This research instrument uses a learning saturation scale that has been tested for validity and reliability. In addition to the scale, decision making in this study used the normality test and SPSS 26-assisted T test. Based on the results of the study, 6 students had medium and high categories with details of 2 students having high scores and 4 having moderate scores. After being given the service, the 6 students experienced a decrease in score. This can be shown by the pretest score which totaled 344 with a mean of 57.3 then after being given group guidance services the problem-solving technique decreased with a total score of 231 with a mean of 38.5. In addition, based on the results of the sample t test, it is known that the sig. (2 tailed) is 0.001 meaning that 0.001 is less than <0.05, then Ha is accepted, and Ho is rejected. So, it can be concluded that group guidance services with problem solving techniques are effective in preventing student learning saturation.

Back-to-back inclusive dijets in DIS at small x: gluon Weizsäcker-Williams distribution at NLO

In [1], we performed the first complete computation of the back-to-back inclusive dijet cross-section in Deeply Inelastic Scattering (DIS) at small xBj to next-to-leading order (NLO) in the Color Glass Condensate effective field theory (CGC EFT). We demonstrate here that for dijets with relative transverse momentum P⊥ and transverse momentum imbalance q⊥, to leading power in q⊥/P⊥, the cross-section for longitudinally polarized photons can be fully factorized into the product of a perturbative impact factor and the non-perturbative Weizsäcker-Williams (WW) transverse momentum dependent (TMD) gluon distribution to NLO accuracy. The impact factor can further be expressed as the product of a universal soft factor which resums Sudakov double and single logs in P⊥/q⊥ and a coefficient function given by a remarkably compact analytic expression. We show that in the CGC EFT the WW TMD satisfies a kinematically constrained JIMWLK renormalization group evolution in rapidity. This factorization formula is valid to all orders in Qs/q⊥ for q⊥, Qs ≪ P⊥, where Qs is the semi-hard saturation scale that grows with rapidity.