Color Dependence Research Articles

Mock Observations: Three Different Types of Galaxy Alignment in TNG100 Simulations

In this study, galaxy samples have been generated using mock observation techniques based on the results of TNG100-1 simulations to investigate three forms of intrinsic alignment: satellite-central alignment between the orientation of the brightest group galaxies (BGG) and the spatial distribution of their satellites, radial alignment between the satellites’ orientation and the direction toward their BGG, as well as direct alignment between the orientation of BGG and that of its satellites. Overall, the predictions of galaxy alignment generally align with observations, although minor discrepancies have been identified. For satellite-central alignment, the alignment strength and color-dependence trends are well replicated by the mock observations. Regarding radial alignment, the signals are weak but discernible, with no apparent color dependence. As for direct alignment, no signal is detected, nor is there any color dependence. We also investigate the alignment dependencies on halo or the BGG properties, and proximity effect. For satellite-central alignment, the predicted alignment signal shows a positive correlation with halo and BGG mass, consistent with observations and previous predictions. Similar correlations have also been observed with the BGG age and metallicity, which merit future observational analysis for confirmation. Proximity effects have been observed for all three types of alignment, with satellites closer to the BGG exhibiting stronger alignment signals. The influence of galaxy definition and shape determination on alignment studies is also analyzed. This study underscores the importance of employing mock observation techniques for a fair comparison between predictions and observations.

Colour dependence of dipole in CatWISE2020 data

ABSTRACT The signal of dipole anisotropy in quasar number counts is studied using the CatWISE2020 catalogue in various colour bins. It is found that the dipole signal differs significantly in two colour bins, namely $W1-W2\lt 1.1$ and $W1-W2\gt 1.1$. While the dipole in the bin $W1-W2\lt 1.1$ points close to the direction of the cosmic microwave background dipole, the dipole in the bin $W1-W2\gt 1.1$ points in the direction $(l,b) = (194^\circ \pm 7^\circ ,19^\circ \pm 4^\circ)$, quite close to the Galactic plane. Despite the proximity to the Galactic plane, we are unable to attribute this signal to a Galactic bias. If we interpret the dipole in the bin $W1-W2\lt 1.1$ as due to our local motion, the extracted velocity turns out to be $900\pm 113$ km s$^{-1}$, which deviates from the cosmic microwave background dipole velocity with approximately 4.7σ significance. We speculate that the dipole signal in both bins is of cosmological origin and that the difference may be attributed to a redshift dependence of the dipole, representing a departure from the standard $\Lambda$CDM model.

Intercomparison of optical scattering turbidity sensors for a wide range of suspended sediment types and concentrations

To monitor the effects of rapid changes in climate and land use on sediment export from erodible environments, it is crucial to accurately quantify highly fluctuating suspended sediment concentrations (SSCs) in contrasted river systems that drain small to mesoscale catchments. To this end, we investigate the turbidity-based quantification of SSCs in the range of 0.05–100 g/L through laboratory experiments performed with 7 different types of turbidity sensors and sediments from 10 watersheds. We find that measurements of scattered light from multiple angles may allow for: (1) an extended monitoring range with SSCs up to 10–100 g/L, where enhanced uncertainty may occur near the transition in the effective operational ranges of the underlying signals (typically somewhere in the range of 1–10 g/L); and/or (2) a slightly reduced sensitivity to sediment properties. The specific turbidity of the investigated sensors is inversely related to particle diameter (D10) for SSCs up to 1–5 g/L. Backscatter and combined-signal sensors also show a dependency on sediment colour (CIE a∗), which becomes particularly prominent at SSCs above 10 g/L. We relate this increase in colour dependency with SSC to the expected effect of cumulative near-infrared light absorption associated with multiple scattering. We discuss covarying physical properties of naturally occurring river sediment that can dampen or enhance measurement sensitivity and result in turbidity-based SSC rating curves that may strongly differ in magnitude and form from curves derived for industrially prepared material that is often used for sensor calibration. Although the differences in SSC per sensor among sediment types are generally less than one order of magnitude, the systematic errors and uncertainties associated with high SSCs are typically greater than one order of magnitude and may disproportionally affect the quantification of sediment loads during large-magnitude flow events.

An Empirical Calibration of the Tip of the Red Giant Branch Distance Method in the Near Infrared. I. Hubble Space Telescope WFC3/IR F110W and F160W Filters

The tip of the red giant branch (TRGB) based distance method in the I band is one of the most efficient and precise techniques for measuring distances to nearby galaxies (D ≲ 15 Mpc). The TRGB in the near-infrared (NIR) is 1–2 mag brighter relative to the I band, and has the potential to expand the range over which distance measurements to nearby galaxies are feasible. Using Hubble Space Telescope (HST) imaging of 12 fields in eight nearby galaxies, we determine color-based corrections and zero-points of the TRGB in the Wide Field Camera 3 IR (WFC3/IR) F110W and F160W filters. First, we measure TRGB distances in the I band equivalent Advanced Camera System (ACS) F814W filter from resolved stellar populations with the HST. The TRGB in the ACS F814W filter is used for our distance anchor and to place the WFC3/IR magnitudes on an absolute scale. We then determine the color dependence (a proxy for metallicity/age) and zero-point of the NIR TRGB from photometry of WFC3/IR fields that overlap with the ACS fields. The new calibration is accurate to ∼1% in distance relative to the F814W TRGB. Validating the accuracy of the calibrations, we find that the distance modulus for each field using the NIR TRGB calibration agrees with the distance modulus of the same field as determined from the F814W TRGB. This is a JWST preparatory program, and the work done here will directly inform our approach to calibrating the TRGB in JWST NIRCam and NIRISS photometric filters.

On the evaluation of deep learning interpretability methods for medical images under the scope of faithfulness

Background and Objective:Evaluating the interpretability of Deep Learning models is crucial for building trust and gaining insights into their decision-making processes. In this work, we employ class activation map based attribution methods in a setting where only High-Resolution Class Activation Mapping (HiResCAM) is known to produce faithful explanations. The objective is to evaluate the quality of the attribution maps using quantitative metrics and investigate whether faithfulness aligns with the metrics results. Methods:We fine-tune pre-trained deep learning architectures over four medical image datasets in order to calculate attribution maps. The maps are evaluated on a threefold metrics basis utilizing well-established evaluation scores. Results:Our experimental findings suggest that the Area Over Perturbation Curve (AOPC) and Max-Sensitivity scores favor the HiResCAM maps. On the other hand, the Heatmap Assisted Accuracy Score (HAAS) does not provide insights to our comparison as it evaluates almost all maps as inaccurate. To this purpose we further compare our calculated values against values obtained over a diverse group of models which are trained on non-medical benchmark datasets, to eventually achieve more responsive results. Conclusion:This study develops a series of experiments to discuss the connection between faithfulness and quantitative metrics over medical attribution maps. HiResCAM preserves the gradient effect on a pixel level ultimately producing high-resolution, informative and resilient mappings. In turn, this is depicted in the results of AOPC and Max-Sensitivity metrics, successfully identifying the faithful algorithm. In regards to HAAS, our experiments yield that it is sensitive over complex medical patterns, commonly characterized by strong color dependency and multiple attention areas.

Colorimetric pH-sensitive hydrogel film based on kappa-carrageenan containing quercetin or eucalyptus leaf extract for freshness monitoring of chicken meat

In this study, we created new pH-sensitive hydrogel films using κ-carrageenan (CG) and either quercetin (QUE) or eucalyptus leaf extract (ELE) to monitor the spoilage of chicken meat. The ability to monitor and control freshness was confirmed by observing the dependence of color on pH changes and measuring total volatile basic nitrogen (TVB-N) levels for CG-QUE (26.5) and CG-ELE (29.75). After conducting a UV–Vis analysis, it was established that films containing 0.3 % of QUE or ELE, with transparency levels above 90 %, have the potential for further research. We found that CG-ELE was more effective in preventing bacterial growth and reducing spoilage compared to CG-QUE. The CG-ELE film also had superior mechanical behavior with higher tensile strength (13.2 ± 0.6 MPa) and lower elongation at break of (5 ± 0.1). Our findings confirmed the preference and superiority of ELE over QUE based on colorimetric response and antibacterial properties.

Angular Dependence of Reflection Spectra and Color for Anodic Alumina Possessing the Photonic Crystal Properties

The angular dependences of visible wavelengths mirror reflection spectra and color characteristics of one-dimensional photonic crystal (PC) based on anodic alumina impregnated with water and isopropyl alcohol are investigated. The photonic crystal was fabricate by anodizing of aluminum in 1M sulfuric acid solution with ethylene glycol addition under periodically varying current density of 0,40 mA/cm2 and 1,80 mA/cm2. The photonic crystal was impregnated using immersion and exposure in liquids for at least 5 hours at room temperature. The short-wavelength shift of photonic band gap spectral position for the photonic crystals has been established under the irradiation incidence angle increase from 25° to 45°. The bathochromic shift of 45 nm has been detected when water was introduced into the photonic crystal pores and 60 nm when isopropyl alcohol was introduced, under the irradiation angle of 25°. The color and chromaticity coordinates on chromaticity diagram have been determined using the CIE 1931 (XYZ). The significant difference in colorimetric characteristics for initial and impregnated PC has been established, the visual color difference being maintained between PC impregnated with substances varying in refractive indices by 0,045.

Evaluation of a polarization-enhanced laparoscopy prototype for improved intra-operative visualization of peritoneal metastases

Despite careful staging, the accuracy for preoperative detection of small distant metastases remains poor, creating a clinical need for enhanced operative staging to detect occult peritoneal metastases. This study evaluates a polarization-enhanced laparoscopy (PEL) prototype and assesses its potential for label-free contrast enhancement of peritoneal metastases. This is a first-in-human feasibility study, including 10 adult patients who underwent standard staging laparoscopy (SSL) for gastrointestinal malignancy along with PEL. Image frames of all detectable peritoneal lesions underwent analysis. Using Monte Carlo simulations, contrast enhancement based on the color dependence of PEL (mPEL) was assessed. The prototype performed safely, yet with limitations in illumination, fogging of the distal window, and image co-registration. Sixty-five lesions (56 presumed benign and 9 presumed malignant) from 3 patients represented the study sample. While most lesions were visible under human examination of both SSL and PEL videos, more lesions were apparent using SSL. However, this was likely due to reduced illumination under PEL. When controlling for such effects through direct comparisons of integrated (WLL) vs differential (PEL) polarization laparoscopy images, we found that PEL imaging yielded an over twofold Weber contrast enhancement over WLL. Further, enhancements in the discrimination between malignant and benign lesions were achieved by exploiting the PEL color contrast to enhance sensitivity to tissue scattering, influenced primarily by collagen. In conclusion, PEL appears safe and easy to integrate into the operating room. When controlling for the degree of illumination, image analysis suggested a potential for mPEL to provide improved visualization of metastases.

Optical interference coatings for coloured building integrated photovoltaic modules: Predicting and optimising visual properties and efficiency

The presented work is focusing on optical interference coatings on the back side of the front glass for crystalline silicon-based photovoltaic modules. We present results on how such coatings can be designed to obtain desired visual properties combined with a limited loss in power conversion efficiency. This colouring technology may therefore be very attractive for building integrated photovoltaics. Coating design parameters such as number of layers, design wavelength, layer thicknesses, and layer refractive indices affect both the visual appearance parameters and the efficiency. Important colour parameters are lightness, chroma, and hue, and we demonstrate how these colour parameters are influenced by the design parameters of the optical interference coating.Using optical interference coatings to create colours results in colours that are dependent on the observation angle. We have introduced a new parameter for quantification of angular colour dependence. Our results show that the angular colour dependence can be reduced by increasing the refractive indices of the interference coating.For many building projects it may be highly desired to combine high power conversion efficiency with certain visual properties. The results from our work also indicate some of the possibilities and challenges in this regard.

Structural Design of Intelligent Reversible Two-Way Structural Color Films.

Structural color always shows a reversible switch between reflection and transmission states when viewed from different angles, attracting increasing attention in display applications. However, this switching between reflection and transmission states of structural color suffers from the inherent lack of autonomous regulation, which is unmanageable in the case of different application scenarios. Here, we design an intelligent two-way structural color film which can reversibly change its color when applied with an extra stimulation such as voltage, heat signal, or light. A special structural feature contains a traditional photonic crystal film of polystyrene (PS) microspheres assembled by smart windows. Remarkably, our structural color film shows a prominent polarization sensitivity, and the angle dependence of the structural color broadens the gamut of display color demonstrated by both finite element theoretical analysis and experimental observation. Prospectively, this hierarchically designed film provides a promising pathway toward next-generation multicolor displays and smart windows.

Environmental Dependence of Different Colors of Active Galactic Nucleus (AGN) Host Galaxies

Environmental Dependence of Different Colors of Active Galactic Nucleus (AGN) Host Galaxies

Preparation of para-aramid aerogel fiber structurally colored by light scattering through wet spinning and supercritical drying

This research is an investigation of the preparation conditions for para-aramid aerogel fibers that are structurally colored by Rayleigh scattering, an angle-independent structural color. It is well known that structural color has the angle dependence of colors. However, there is currently a desire for materials with angle-independent structural color. During the fibers’ spinning process, the microstructures of the fibers are generated. The effect of spinning conditions is investigated by measuring the optical properties of the wet gel fibers. The neutralization speed of negatively charged PPTA fibrils has a significant impact on the formation of the dense microstructure. Spinning under the fast neutralization speed condition makes it possible to achieve the blue-colored fiber derived from Rayleigh scattering. The influence of neutralization speed on the microstructure of the fibers is confirmed by FE-SEM characterization. Furthermore, spinning using a narrow inner diameter needle decreases the whiteness component derived from Mie scattering of the fibers, resulting in a more vivid blue color. The angle-independent structurally colored fibers hold great promise for application in clothing, interiors, and industrial materials.

Temperature dependence of luminescence color of Mn2+-doped ZnCN2 phosphor

Photoluminescent materials which show multi-wavelength luminescence have potential applications in temperature sensing device. In this study, Mn2+-doped ZnCN2 phosphor was prepared by ammonia nitridation of Zn-Mn oxalate precursors in the presence of carbon nitride. Upon UV excitation, it showed photoluminescence band at 580 nm due to isolated Mn2+ ions as well as minor broad emission bands at 500 and 670 nm due to anion vacancies and Mn-Mn pairs in the ZnCN2, respectively. Since the intensities of the luminescent bands had different temperature dependencies, and the total luminescence color changed from orange at 80 K to yellow green at 500 K.

PAH Emission from Star-forming Galaxies in JWST Mid-infrared Imaging of the Lensing Cluster SMACS J0723.3-7327

The mid-infrared spectra of star-forming galaxies (SFGs) are characterized by characteristic broad polycyclic aromatic hydrocarbon (PAH) emission features at 3–20 μm. As these features are redshifted, they are predicted to dominate the flux at specific mid-infrared wavelengths, leading to substantial redshift-dependent color variations in broadband photometry. The advent of JWST for the first time allows the study of this effect for normal SFGs. Based on spectral energy distribution templates, we here present tracks in mid-infrared (4.4, 7.7, 10, 15, and 18 μm) color–color diagrams describing the redshift dependence of SFG colors. In addition, we present simulated color–color diagrams by populating these tracks using the cosmic star formation history and the star formation rate function. Depending on redshift, we find that SFGs stand out in the color–color diagrams by several magnitudes. We provide the first observational demonstration of this effect for galaxies detected in the JWST Early Release Observations of the field toward the lensing cluster SMACS J0723.3−7327. While the distribution of detected galaxies is consistent with the simulations, the numbers are substantially boosted by lensing effects. The PAH emitter with the highest spectroscopic redshift, detected in all bands, is a multiply imaged galaxy at z = 1.45. There is also a substantial number of cluster members that do not exhibit PAH emission except for one SFG at z = 0.38. Future wider-field observations will further populate mid-infrared color–color diagrams and provide insight into the evolution of typical SFGs.

Mass and Color Dependence of the Hubble Spiral Sequence

In the classic Hubble spiral sequence, arm windiness correlates with bulge size; Sa type spiral galaxies with larger bulges also have the most tightly wound spirals. Exceptions to this have long been known, and in recent work using Galaxy Zoo morphologies no strong correlation was seen in a volume limited sample. In this Research Note, we explore the impact of galaxy mass and integrated color upon this correlation in the Galaxy Zoo sample, finding that bluer and lower mass spirals show the “expected” correlation; however, it becomes slightly negative for redder and/or more massive spiral galaxies.

Perturbative and non-perturbative interactions between heavy quarks and quark-gluon plasma within a unified approach

While perturbative QCD is sufficient for understanding the color, mass and energy dependences of parton energy loss and jet quenching at large transverse momentum in heavy-ion collisions, a simultaneous description of heavy flavor nuclear modification factor RAA and elliptic flow coefficient v2 at low and intermediate pT still remains a challenge due to the effects from non-perturbative interactions. In this work, we extend the linear Boltzmann transport model by implementing a generalized Cornell-type potential that incorporates both short-range Yukawa interaction and long-range color confining interaction between heavy quarks and the QGP medium. Combining our new approach for heavy-quark-QGP interaction with a (3+1)-dimensional hydrodynamic model CLVisc for the QGP evolution and a hybrid fragmentation-coalescence model for heavy quark hadronization, we obtain a satisfactory description of heavy meson RAA and v2 from low to intermediate to high pT observed at both RHIC and the LHC. By model-data-comparison, we obtain for the first time the in-medium heavy quark potential from open heavy flavor measurements; the result is in agreement with the lattice QCD calculation. Our study indicates that while jet quenching at high pT is dominated by perturbative QCD interactions, non-perturbative interactions are indispensible for understanding heavy flavor quenching and flow at low and intermediate pT.

Development and analysis of a mathematical model for an automatic control system for the printer paper color characteristics

The stability of the paper optical characteristics depends entirely on the control system for the dosage of the bleaching agent and colorants, which construction is impossible without a mathematical description of this process. The article presents mathematical models of an automatic system control object that describe the dependence of paper color coordinates from the consumption of chemical reagents-colorants and bleaches of various brands. Keywords paper quality, paper optical properties, paper color management system, paper color coordinates L*, a*, b*, mathematical model, paper stock composition, optical brightener, colorants

Color Dependence of the Transit Detectability of Young Active M Dwarfs

We investigate the planetary transit detectability in the presence of stellar rotational activity from light curves of young M dwarfs, and estimate the improvements in detection at near-infrared (NIR) wavelengths. By making maps of the transit signal detection efficiency over the orbital period and planetary radius with light curves of the members of four clusters observed by the K2 mission—Hyades, Praesepe, Pleiades, and Upper Scorpius—we evaluate the detectability of the rotation period and the modulation of the semi-amplitude. We find that the detection efficiency decreases remarkably, to about 20%, for rapid rotators with P rot ≤ 1 day, and that the lack of planets in Pleiades is likely due to the high fraction of rapidly rotating M dwarfs. We also evaluate the improvements in planet detection with NIR photometry via tests that use mock light curves, assuming that the signal amplitude of the stellar rotation decreases at NIR wavelengths. Our results suggest that NIR photometric monitoring will double the relative detection efficiency for transiting planetary candidates with P rot ≤ 1 day, and find planets around M dwarfs with approximately 100 Myr that are missing from previous transit surveys from space.

Color dependence of the topological susceptibility in Yang-Mills theories

For Yang-Mills theories in four dimensions, we propose to rescale the ratio between topological susceptibility and string tension squared in a universal way, dependent only on group factors. We apply this suggestion to SU(Nc) and Sp(Nc) groups, and compare lattice measurements performed by several independent collaborations. We show that the two sequences of (rescaled) numerical results in these two families of groups are compatible with each other. We hence perform a combined fit, and extrapolate to the common large-Nc limit.

Dependence of colour, OD254 and SUVA254 of river water from pollution by domestic wastewaters

In several points of rivers Toksa, Neva and water objects related to them chemical analysis of water was done, optical density at 254 nm (OD254) and SUVA254 were determined. Tributaries of the Toksa polluted by domestic wastewaters showed values increased several fold (compared to the Toksa waters) for: colour, OD254, TOC, electric conductivity (EC), concentrations of ammonium (up to 10 maximal allowable levels for surface waters) and chlorides. SUVA254 (in L/(mgTOC·m)) belonged to the following ranges: 1.8-3.0 in the Toksa and its source; 2.3-6.3 in its polluted tributaries; 2.7-3.5 in the Neva and its source; 2.1-2.6 in the tap water of St. Petersburg. For express control of the pollution in the Toksa and other rivers with similar properties measurement of EC and OD254 could be recommended. Control of organic matter content based solely on OD254 cannot be precise due to variations of SUVA254.