Dimming Effect Research Articles

Doppler dimming and brightening effects in solar prominences

ABSTRACT We explored the impact that Doppler dimming and brightening effects from bulk motions of solar prominences have on the formation of Ly $~\alpha$, H $~\alpha$, and Mg ii h line profiles. We compared two schemes in which these effects manifest; when the prominence is moving radially away from the solar surface (radial case), and when the prominence is moving parallel to the solar surface (horizontal case). To do this, we analysed 13 332 model profiles generated through the use of the 1D NLTE (i.e. departures from Local Thermodynamic equilibrium) radiative transfer (RT) code promweaver, built on the lightweaver NLTE RT framework to mimic the behaviour and output of the 1D NLTE RT code prom. We found that horizontal velocities are just as, or more important than radial velocities. This demonstrates that horizontal velocities need to be accounted for when attempting to do any sort of forward modelling.

Review of equations to predict methane emissions in dairy cows from milk fatty acid profiles and their application to commercial dairy farms

Greenhouse gas emission from the activities of all productive sectors is currently a topic of foremost importance. The major contributors in the livestock sector are ruminants, especially dairy cows. This study aimed to evaluate and compare 21 equations for predicting enteric methane emissions (EME) developed on the basis of milk traits and fatty acid profiles, which were selected from 46 retrieved through a literature review. We compiled a reference database of the detailed fatty acid profiles, determined by GC, of 992 lactating cows from 85 herds under 4 different dairy management systems. The cows were classified according to DIM, parity order, and dairy system. This database was the basis on which we estimated EME using the selected equations. The EME traits estimated were methane yield (20.63 ± 2.26 g/kg DMI, 7 equations), methane intensity (16.05 ± 2.76 g/kg of corrected milk, 4 equations), and daily methane production (385.4 ± 68.2 g/d, 10 equations). Methane production was also indirectly calculated by multiplying the daily corrected milk yield by the methane intensity (416.6 ± 134.7 g/d, 4 equations). We also tested for the effects of DIM, parity, and dairy system (as a correction factor) on the estimates. In general, we observed little consistency among the EME estimates obtained from the different equations, with exception of those obtained from meta-analyses of a range of data from different research centers. We found all the EME predictions to be highly affected by the sources of variation included in the statistical model: DIM significantly affected the results of 19 of the 21 equations, and parity order influenced the results of 13. Different patterns were observed for different equations with only some of them in accordance with expectations based on the cow's physiology. Finally, the best predictions of daily methane production were obtained when a measure of milk yield was included in the equation or when the estimate was indirectly calculated from daily milk yield and methane intensity.

The debiased morphological transformations of galaxies since z=3 in CANDELS

Morphological quantitative measurements and visual-like classifications are susceptible to biases arising from the expansion of the Universe. One of these biases is the effect of cosmological surface brightness dimming (CSBD): the measured surface brightness of a galaxy decays with redshift as $(1+z)^ $. This effect might lead an observer to perceive an altered morphology compared to the real one. Our goal is to investigate the impact of CSBD on morphological classifications to determine the true evolution of morphological classes over redshift for field galaxies, and to interpret these results in the context of morphological transformations and star formation quenching. We employed artificial redshifting techniques on a sample of 268 galaxies in the five CANDELS fields, spanning redshifts from $z=0.2$ to $z=3.0$. We compared the visual classifications and morphological coefficients ($G$, $M_ $, and $A_s$) obtained from the original and simulated images. Subsequently, we developed two correction methods to mitigate the effects of CSBD. Our findings reveal that CSBD, low resolution, and signal-to-noise significantly bias the visual morphological classifications beyond $z>1$. Specifically, we observed an overestimation of the fractions of spheroids and irregular galaxies by up to $50<!PCT!>$, while the fractions of early- and late-type disks were underestimated by $10<!PCT!>$ and $50<!PCT!>$, respectively. However, we found that morphological coefficients are not significantly affected by CSBD at $z<2.25$. We validated the consistency of our correction methods by applying them to the observed morphological fractions in the IllustrisTNG-50 sample and comparing them to previous studies. We propose two potential sources of confusion regarding the visual classifications due to CSBD. Firstly, galaxies may be misclassified as spheroids, as the dimming effect primarily renders the bulge component visible. Secondly, galaxies may be misidentified as irregulars due to their more diffuse and asymmetric appearance at high redshifts. By analyzing the morphological fractions of star-forming and quiescent subsamples as a function of redshift and stellar mass, we propose a scenario where late-type disks transform into quiescent spheroids through mergers or to early-type disks through secular evolution or active galactic nucleus feedback.

A Numerical Modeling Study on the Earth’s Surface Brightening Effect of Cirrus Thinning

Cirrus thinning, as one kind of geoengineering approach, not only cools our planet but also enhances the amount of sunlight reaching the Earth’s surface (brightening effect). This study delves into the brightening effect induced by cirrus thinning with a flexible seeding method. The thinning of cirrus clouds alone leads to a considerable globally averaged cooling effect (−2.46 W m−2), along with a notable globally averaged brightening effect (2.19 W m−2). Cirrus thinning also results in substantial reductions in the cloud radiative effects of the lower mixed-phase and liquid clouds. While these reductions counteract the cooling effect from cirrus clouds, they enhance the brightening effect from cirrus clouds. Consequently, the brightening effect caused by cirrus seeding (4.69 W m−2) is considerably stronger than its cooling effect (−1.21 W m−2). Furthermore, due to the more pronounced changes from the mixed-phase and liquid clouds at low and mid-latitudes, the cooling effect is primarily concentrated at high latitudes. In contrast, the brightening effect is stronger over most low- and mid-latitude regions. Overall, cirrus thinning could lead to a notable brightening effect, which can be leveraged to offset the dimming effect (the opposite of the brightening effect) of other geoengineering approaches.

Effect of Cosmic Plasma on the Observation of Supernovae Ia

In observational cosmology, a supernova Ia is used as a standard candle in order to extend the Hubble diagram to a higher redshift range. Astrophysicists found that the observed brightness of high redshift supernovae Ia is dimmer than expected. This dimming effect is considered observational evidence for the existence of dark energy in the universe. It should be noted that this conclusion is based on an assumption that the mass density of the cosmic plasma is very small. Therefore, the dimming effect caused by the Compton scattering of free electrons in cosmic plasma can be neglected. X-ray observations suggest that the mass density of the cosmic plasma may be very large. In theory, the observed dimming effect of high redshift supernovae Ia may be caused by the Compton scattering of free electrons in the cosmic plasma. In this paper it will be shown that this idea is reasonable. Therefore, there is no need to introduce the confusing concept of dark energy into cosmology.

The Structure and Morphology of Galaxies during the Epoch of Reionization Revealed by JWST

We analyze 347 galaxies at redshift 4 < z < 9.5 using JWST observations from the Cosmic Evolution Early Release Science (CEERS) program by simultaneously fitting a two-dimensional parametric model to the seven-filter Near Infrared Camera images to measure the overall structural parameters and quantify the global properties of the galaxies in the rest-frame optical band. Particular attention is devoted to deriving robust uncertainties that include, among other factors, the influence of cosmological surface brightness dimming and resolution effects. Using the global Sérsic index (n < 1.5) and observed axial ratio (q < 0.6) as a guide, we place a conservative lower limit of ∼45% on the incidence of galactic disks. Galaxies follow a relation between the rest-frame optical luminosity and effective radius in the redshift range 4 < z < 9.5, as well as separately over the intervals 4 < z < 5 and 5 ≤ z < 9.5, with a very similar slope but a marginally lower zero-point in the higher-redshift bin (R e = 0.69 ± 0.05 kpc) compared to the lower-redshift bin (R e = 0.91 ± 0.04 kpc). Within the limitations of the current sample size, we find no significant redshift evolution of n or R e at these early epochs.

Progress in direct measurements of the Hubble constant

One of the most exciting and pressing issues in cosmology today is the discrepancy between some measurements of the local Hubble constant and other values of the expansion rate inferred from the observed temperature and polarization fluctuations in the cosmic microwave background (CMB) radiation. Resolving these differences holds the potential for the discovery of new physics beyond the standard model of cosmology: Lambda Cold Dark Matter (ΛCDM), a successful model that has been in place for more than 20 years. Given both the fundamental significance of this outstanding discrepancy, and the many-decades-long effort to increase the accuracy of the extragalactic distance scale, it is critical to demonstrate that the local measurements are convincingly free from residual systematic errors. We review the progress over the past quarter century in measurements of the local value of the Hubble constant, and discuss remaining challenges. Particularly exciting are new data from the James Webb Space Telescope (JWST), for which we present an overview of our program and first results. We focus in particular on Cepheids and the Tip of the Red Giant Branch (TRGB) stars, as well as a relatively new method, the JAGB (J-Region Asymptotic Giant Branch) method, all methods that currently exhibit the demonstrably smallest statistical and systematic uncertainties. JWST is delivering high-resolution near-infrared imaging data to both test for and to address directly several of the systematic uncertainties that have historically limited the accuracy of extragalactic distance scale measurements (e.g., the dimming effects of interstellar dust, chemical composition differences in the atmospheres of stars, and the crowding and blending of Cepheids contaminated by nearby previously unresolved stars). For the first galaxy in our program, NGC 7250, the high-resolution JWST images demonstrate that many of the Cepheids observed with the Hubble Space Telescope (HST) are significantly crowded by nearby neighbors. Avoiding the more significantly crowded variables, the scatter in the JWST near-infrared (NIR) Cepheid PL relation is decreased by a factor of two compared to those from HST, illustrating the power of JWST for improvements to local measurements of H 0. Ultimately, these data will either confirm the standard model, or provide robust evidence for the inclusion of additional new physics.

Inhibition of the interaction between Hippo/YAP and Akt signaling with ursolic acid and 3'3-diindolylmethane suppresses esophageal cancer tumorigenesis.

Hippo/YAP signaling hinders cancer progression. Inactivation of this pathway contributes to the development of esophageal cancer by activation of Akt. However, the possible interaction between Akt and Hippo/YAP pathways in esophageal cancer progression is unclear. In this study, we found that ursolic acid (UA) plus 3'3-diindolylmethane (DIM) efficiently suppressed the oncogenic Akt/Gsk-3β signaling pathway while activating the Hippo tumor suppressor pathway in esophageal cancer cells. Moreover, the addition of the Akt inhibitor LY294002 and the PI3K inhibitor 3-methyladenine enhanced the inhibitory effects of UA plus DIM on Akt pathway activation and further stimulated the Hippo pathway, including the suppression of YAP nuclear translocation in esophageal cancer cells. Silencing YAP under UA plus DIM conditions significantly increased the activation of the tumor suppressor PTEN in esophageal cancer cells, while decreasing p-Akt activation, indicating that the Akt signaling pathway could be down-regulated in esophageal cancer cells by targeting PTEN. Furthermore, in a xenograft nude mice model, UA plus DIM treatment effectively diminished esophageal tumors by inactivating the Akt pathway and stimulating the Hippo signaling pathway. Thus, our study highlights a feedback loop between the PI3K/Akt and Hippo signaling pathways in esophageal cancer cells, implying that a low dose of UA plus DIM could serve as a promising chemotherapeutic combination strategy in the treatment of esophageal cancer.

How solar panels work, in theory and in practice

We present an analysis of the functionality of an array of monocrystalline silicon solar panels over a 22 month period. For simple geometrical reasons, one expects the solar power produced to be linearly proportional to the cosine of the incidence angle of the Sun’s light on the panels. This can be demonstrated with high accuracy (root-mean-square scatter of less than one percent), but one must first correct the measured solar power for the dimming effect of the Earth’s atmosphere as a function of the atmospheric path length that the Sun’s light traverses. We elaborate a simple and robust method for determining the atmospheric extinction term on days with clear sky conditions. There are two situations under which the extinction-corrected data deviate from the linear relation. One is due to the heating of the panels during daylight hours, resulting in their being less efficient. The other is manifested as an increase of power that occurs when the sky is partially filled with reflective clouds. This is the phenomenon of cloud enhancement.

Low-surface-brightness Galaxies are Missing in the Observed Stellar Mass Function

We investigate the impact of the surface-brightness (SB) limit on the galaxy stellar mass functions (GSMFs) using galaxy catalogs generated from the Horizon Run 5 (HR5) simulation. We compare the stellar-to-halo-mass relation, GSMF, and size–stellar mass relation of the HR5 galaxies with observational data and other cosmological simulations. The mean SB of simulated galaxies are computed using their effective radii, luminosities, and colors. To examine the cosmic SB dimming effect, we compute k-corrections from the spectral energy distributions of individual simulated galaxy at each redshift, apply the k-corrections to the galaxies, and conduct mock surveys based on the various SB limits. We find that the GSMFs are significantly affected by the SB limits at the low-mass end. This approach can ease the discrepancy between the GSMFs obtained from simulations and observations at 0.6 ≲ z ≤ 2. We also find that a redshift survey with an SB selection limit of 25 mag arcsec−2 will miss 20% of galaxies with at z = 0.625. The missing fraction of low-surface-brightness galaxies increases to 35%, 55%, and 80% at z = 0.9, 1.1, and 1.9, respectively, at the same SB limit.

Relationship Between the Aerosol Loadings Over the Bay of Bengal and the Arabian Sea in the Early Summer and Asian Monsoon Rainfall Anomalies, and the Role of SST Anomalies in the Indian Ocean

AbstractTwo relatively long‐term satellite aerosol products during 1983–2020 and 2000–2020 are employed to investigate interannual relationships between anomalous aerosol loadings over the Bay of Bengal (BoB) and Arabian Sea (AS) in the early summer and Asian monsoon rainfall anomalies. It is shown that increased aerosol loading (IAL) over the BoB is primarily attributed to an intensified upstream aerosol transport by anomalous subtropical westerly winds and coincides with local sea surface temperature (SST) cooling due to intensified prevailing wind and the aerosol dimming effect, and vice versa. A deficient rainfall in India tends to concur with a BoB IAL while excessive rainfall with an AS IAL in May and June. In June, a BoB IAL coincides with significantly deficient rainfall in the southwestern China‐Huaihe River Basin primarily linked to an anomalous cyclone off the coast of Southeast China. Meanwhile a related overturning of Walker Circulation is identified to be driven by the contrast of anomalous convective activity between the southeastern Indian‐BoB and the South China Sea‐Philippine Sea. An AS IAL is associated with air warming in North India due to an elevated aerosol semi‐direct effect and remote forcing that reinforces the meridional air temperature gradient. The IAL over the respective BoB and AS in June are both preceded by cold SST anomalies in the western Indian Ocean that can be traced back to the preceding winter, but the corresponding atmospheric circulations driving aerosol‐monsoon interactions differ distinctly. The above aerosol‐monsoon relationships are sustained primarily during 2000–2020 and vague during 1983–2020.

Updated Measurements of [O iii] 88 μm, [C ii] 158 μm, and Dust Continuum Emission from a z = 7.2 Galaxy

We present updated measurements of the [O iii] 88 μm, [C ii] 158 μm, and dust continuum emission from a star-forming galaxy at z = 7.212, SXDF-NB1006-2, by utilizing Atacama Large Millimeter/submillimeter Array (ALMA) archival data sets analysed in previous studies and data sets that have not been analysed before. The follow-up ALMA observations with higher angular resolution and sensitivity reveal a clumpy structure of the [O iii] emission on a scale of 0.32–0.85 kpc. We also combined all the ALMA [O iii] ([C ii]) data sets and updated the [O iii] ([C ii]) detection to 5.9σ (3.6σ–4.5σ). The non-detection of [C ii] with data from the REBELS large program implies the incompleteness of spectral-scan surveys using [C ii] to detect galaxies with high star formation rates (SFRs) but marginal [C ii] emission at high-z. The dust continuum at 90 and 160 μm remains undetected, indicating little dust content of <3.9 × 106 M ⊙ (3σ), and we obtained a more stringent constraint on the total infrared luminosity. We updated the [O iii]/[C ii] luminosity ratios to 10.2 ± 4.7 (6.1 ± 3.5) and 20 ± 12 (9.6 ± 6.1) for the 4.5σ and 3.6σ [C ii] detections, respectively, where the ratios in the parentheses are corrected for the surface brightness dimming effect on the extended [C ii] emission. We also found a strong [C ii] deficit (0.6–1.3 dex) between SXDF-NB1006-2 and the mean L [C II]−SFR relation of galaxies at 0 < z < 9.

Galaxy interactions are the dominant trigger for local type 2 quasars

ABSTRACT The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 optically selected type 2 quasars – the QSOFEED sample ($L_{\rm [O\, \small {III}]}\gt 10^{8.5}\, \mathrm{L}_{\odot }$; z &amp;lt; 0.14). Based on visual inspection by eight classifiers, we find clear evidence that galaxy interactions are the dominant triggering mechanism for quasar activity in the local universe, with 65$^{+6}_{-7}$ per cent of the type 2 quasar hosts showing morphological features consistent with galaxy mergers or encounters, compared with only 22$^{+5}_{-4}$ per cent of a stellar-mass- and redshift-matched comparison sample of non-AGN galaxies – a 5σ difference. The type 2 quasar hosts are a factor of 3.0$^{+0.5}_{-0.8}$ more likely to be morphologically disturbed than their matched non-AGN counterparts, similar to our previous results for powerful 3CR radio AGN of comparable [O iii] emission-line luminosity and redshift. In contrast to the idea that quasars are triggered at the peaks of galaxy mergers as the two nuclei coalesce, and only become visible post-coalescence, the majority of morphologically disturbed type 2 quasar sources in our sample are observed in the pre-coalescence phase (61$^{+8}_{-9}$ per cent). We argue that much of the apparent ambiguity that surrounds observational results in this field is a result of differences in the surface brightness depths of the observations, combined with the effects of cosmological surface brightness dimming.

Breed, parity, and days in milk affect risk of tongue rolling in dairy cows

Stereotypic behaviors are repetitive, invariant movements with no obvious biological function. Tongue rolling (TR) is a common stereotypic behavior in cattle, characterized by a repeated circular movement of the tongue inside or outside of the mouth. We assessed TR in adult lactating dairy cows (from 45 to 305 d in milk; DIM) on a large commercial US dairy comprised of Jersey and Jersey-Holstein crosses (n = 8,158 cows). Cows were monitored during each of 3 consecutive milkings using video cameras located at the center of 2 rotary parlors. In total, 29.0% (2,365/8,158) of cows tongue rolled at least once, 7.9% (646/8,158) at least twice, and 1.7% (141/8,158) tongue rolled during all 3 milkings. The effects of breed (Jersey vs. Jersey-Holstein cross), parity (first lactation versus older), DIM, and the interactions between breed and parity and DIM on TR (comparing cows that were never observed rolling versus cows observed doing so at least once) were tested using logistic regression, revealing interactions between breed and parity. Among primiparous cows, Jerseys were more likely than Jersey-Holstein crosses to tongue roll [odds ratio (OR) = 1.61, confidence interval (CI) = 1.35–1.92]; similarly, among second-parity and older cows, Jerseys were again more likely to tongue roll than were Jersey-Holstein crosses (OR = 2.35, CI = 1.95–2.83). The effect of DIM differed by breed and parity; for primiparous Jerseys, the odds of TR increased with DIM (OR = 1.31, CI 1.12–1.52, for every 100-d increase), and for Jersey-Holsteins cows the odds of TR decreased with DIM (OR = 0.61, CI 0.43–0.88, for every 100-d increase). These breed, parity, and stage of lactation differences within a single farm suggest a role of both genetic and developmental effects in the proclivity to tongue roll.

3,3'-diindolylmethane inhibits LPS-induced human chondrocytes apoptosis and extracellular matrix degradation by activating PI3K-Akt-mTOR-mediated autophagy.

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by articular cartilage destruction. The pathological mechanisms are complex; in particular, inflammation, autophagy, and apoptosis are often involved. 3,3-Diindolylmethane (DIM), a phytoconstituent extracted from cruciferous vegetables, has various effects such as anti-inflammatory, antioxidant and anti-apoptotic. However, the effects of DIM on osteoarthritic chondrocytes remain undetermined. In this study, we simulated a lipopolysaccharide (LPS)-induced osteoarthritis model in human primary chondrocytes. We found that LPS stimulation significantly inhibited autophagy, induced chondrocyte apoptosis and extracellular matrix (ECM) degradation, which could be ameliorated by DIM. DIM inhibited the expression of a disintegrin and metalloproteinase with thrombospondin motif 5 (ADAMTS-5), matrix metalloproteinase 13 (MMP13), cleaved caspase-3, Bax, and p62, and increased the expression level of collagen II, aggrecan, Bcl-2, light chain 3 Ⅱ (LC3 Ⅱ), and beclin-1. Mechanistic studies showed that DIM increased chondrocyte autophagy levels by inhibiting the activation of PI3K/AKT/mTOR pathway. In mice destabilization of the medial meniscus (DMM) model, immunohistochemical analysis showed that DIM inhibited the expression of p-PI3K and cleaved caspase-3, increased the expression of LC3 Ⅱ. Furthermore, DIM relieved joint cartilage degeneration. In conclusion, our findings demonstrate for the first time that DIM inhibits LPS-induced chondrocyte apoptosis and ECM degradation by regulating the PI3K/AKT/mTOR-autophagy axis and delays OA progression in vivo.

Synthetic Lyman-α emissions for the coronagraph aboard the ASO-S mission

Context. Strong ultraviolet (UV) emission from the sun will be observed by the Lyman-α Solar Telescope (LST) on board the Advanced Space-based Solar Observatory (ASO-S), scheduled for launch in 2022. It will provide continuous observations from the solar disk to the corona below a 2.5 solar radius with high resolution. To configure the appropriate observing modes and also to better understand its upcoming observations, a series of simulations and syntheses of different structures and processes need to be done in advance. Aims. As prominence eruptions are the main drivers of space weather, the need to monitor such phenomena has been set as a priority among the objectives of ASO-S mission. In this work, we synthesize the evolution of a modeled prominence-cavity system before and during its eruption in the field of view (FOV) of LST. Methods. We adopted the input magnetohydrodynamic (MHD) model of a prominence-cavity system, which is readily comparable to the Atmospheric Imaging Assembly (AIA) observations. The Lyman-α emission of the prominence and its eruptive counterparts are synthesized through the PRODOP code, which considers non-local thermodynamic equilibrium (NLTE) radiative transfer processes, while the other coronal part such as the cavity and surrounding streamer, are synthesized with the FORWARD package, which deals with optically thin structures. Results. We present a discussion of the evolution of the eruptive prominence-cavity system, analyzing the synthetic emissions both on the disk near the limb and above the limb as viewed by the coronagraph, as well as the three-dimensional (3D) data of the MHD simulation. Conclusions. The evolution of the prominence-cavity system exhibits the condensation of cavity mass onto the prominence and the evaporation of prominence plasma into the central cavity. The synthetic emission in Lyman-α shows a similar pattern as in the AIA extreme ultraviolet (EUV) wavelengths before eruption, namely, the appearance of a “horn” substructure as a precursor to the eruption. The emission of prominence with an optically thick assumption is one to two orders of magnitude lower than the optically thin one. Here, the dimming effect in Lyman-α is analyzed, for the first time, for the eruptive prominence-cavity system. Accompanying the prominence plasma motion during the eruption, the apparent dimming shows a preferred location evolving from the top and bottom of the bright core to the whole body above the bottom part, while the collisional component progressively dominates the total emission of the flux rope bright core at these locations. By analyzing the signal-to-noise ratio (S/N) with a consideration of LST’s optical design, we conclude that the substructures in the cavity and the bright core of the CME can be observed with sufficient S/N at different stages in the FOV of LST.

A Novel Technique For Enhancing Underwater Visibility Using Non-Local Stretch Directional Gradient

Owing to the many effects of the underwater medium, underwater images are often captured with a hazy quality. These effects are caused by suspended particles in the image forming phase, which cause light absorption and scattering. On account of these pictures with fluctuating levels of dimness and colour variation, traditional algorithms have several disadvantages. Underwater image enhancement’s main goal is to increase the clarity and contrast of underwater photographs in order to solve these issues. Our paper describes a novel technique by combining several algorithms characteristics for achieving the following goals: i) better scattering, (ii) grey world assumption, (iii) non-Local stretch Directional Gradient process. For example, a better scattering model would be better at modelling hazy scenes and overcoming the image illumination dimming effect. Second, for uniform visibility recovery on the captured picture, an appropriate gray world-assumption is used. Finally, the Non-Local stretch and Directional gradient filter work on the edge details and overall dual tone enhancement required for a high-quality picture. Simulation experiments indicate that the proposed methodology produces improved visual effects and has a greater impact on consistency metrics than other methods.

Deep low-excitation fluorescence imaging enhancement

In this work, to the best of our knowledge, we provide the first deep low-excitation fluorescence imaging enhancement solution to reconstruct optimized-excitation fluorescence images from captured low-excitation ones aimed at reducing photobleaching and phototoxicity due to strong excitation. In such a solution, a new framework named Kindred-Nets is designed aimed at improving the effective feature utilization rate; and additionally, a mixed fine-tuning tactic is employed to significantly reduce the required number of fluorescence images for training but still to increase the effective feature density. Proved in applications, the proposed solution can obtain optimized-excitation fluorescence images in high contrast and avoid the dimming effect due to negative optimization from the ineffective features on the neural networks. This work can be employed in fluorescence imaging with reduced excitation as well as extended to nonlinear optical microscopy especially in conditions with low output nonlinear signals. Furthermore, this work is open source available at https://github.com/GuYuanjie/KindredNets.

SILVERRUSH. XII. Intensity Mapping for Lyα Emission Extending over 100–1000 Comoving Kpc around z ∼ 2−7 LAEs with Subaru HSC-SSP and CHORUS Data

We conduct intensity mapping to probe for extended diffuse Lyα emission around Lyα emitters (LAEs) at z ∼2−7, exploiting very deep (∼26 mag at 5σ) and large-area (∼4.5 deg2) Subaru/Hyper Suprime-Cam narrowband (NB) images and large LAE catalogs consisting of a total of 1540 LAEs at z = 2.2, 3.3, 5.7, and 6.6 obtained by the HSC-SSP and CHORUS projects. We calculate the spatial correlations of these LAEs with ∼1–2 billion pixel flux values of the NB images, deriving the average Lyα surface brightness (SBLyα ) radial profiles around the LAEs. By carefully estimating systematics such as fluctuations of sky background and point-spread functions, we detect Lyα emission at 100–1000 comoving kpc around z = 3.3 and 5.7 LAEs at the 3.2σ and 3.7σ levels, respectively, and tentatively (=2.0σ) at z = 6.6. The emission is as diffuse as ∼10−20–10−19 erg s−1 cm−2 arcsec−2 and extended beyond the virial radius of a dark matter halo with a mass of 1011 M ⊙. While the observed SBLyα profiles have similar amplitudes at z = 2.2–6.6 within the uncertainties, the intrinsic SBLyα profiles (corrected for the cosmological dimming effect) increase toward high redshifts. This trend may be explained by increasing hydrogen gas density due to the evolution of the cosmic volume. Comparisons with theoretical models suggest that extended Lyα emission around an LAE is powered by resonantly scattered Lyα photons in the CGM and IGM that originate from the inner part of the LAE and/or neighboring galaxies around the LAE.

Tracing Atmospheric Anthropogenic Black Carbon and Its Potential Radiative Response Over Pan‐Third Pole Region: A Synoptic‐Scale Analysis Using WRF‐Chem

AbstractThe Pan‐Third Pole contains the largest number of glaciers outside the polar region that plays a crucial role in atmospheric circulation and the hydrological cycle. However, this pristine region has undergone rapid change through complex interactions including the black carbon (BC) enhanced warming effect and glacier melting. Study shows, Weather Research and Forecasting coupled with Chemistry (WRF‐Chem) simulation is able to capture distinctive seasonal variability of BC. The result from our sensitivity experiments revealed that South Asia (SA; 60.7%) and East Asia (EA; 32.9%) contributed more toward the Tibetan Plateau (TP). Our analysis on aerosol‐boundary feedback interaction revealed BC expand planetary boundary layer height by 5.0% and 4.8% over SA and EA, respectively, which facilitates BC dispersion and transportation. Whereas, we also found that under the influence of different wind regimes the significant BC transport flux aloft over the TP and the upper troposphere and lower stratosphere. Additionally, mountain‐valley channel and synoptic and local meteorological processes also facilitated BC transport to the TP. This study also evaluated the effect of BC on direct radiative forcing and calculated subsequent temperature changes. A strong dimming effect of BC corroborated with the following negative surface temperature changes. However, enhanced BC concentration during winter and spring caused the increase in temperature over the TP. Here, the WRF‐Chem model, synergy on aerosol‐boundary feedback, BC transport flux, and source‐receptor methods confirmed the significant BC contribution and transportation, and notable BC‐induced warming over TP. Such trans‐Himalayan BC transport and associated warming could grim glacier melt and water availability in the region.