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The main obstacle to efficient calculation of longwave radiative transfer is the existence of multiple radiative sources, each with its own emission spectrum. The work presented here overcomes this problem by combining the full spectrum broadband approach with the net exchanged rate decomposition. The idea is worked out to suit the needs of numerical weather prediction, where the most costly contribution representing the sum of internal exchanges is interpolated between cheap minimum and maximum estimates, while exchange with the surface and dominant cooling to space contributions are calculated accurately. The broad-band approach must address the additional problems related to spectral integration and many ideas developed previously for the solar spectrum are reused. Specific issues appear, the dependence of broadband gaseous transmissions on the temperature of the emitting body being the most important one. The thermal spectrum also brings some simplifications-aerosols, clouds and the Earth's surface can safely be treated as grey bodies. The optical saturation of gaseous absorption remains the main complication and non-random spectral overlaps between gases become much more significant than in the solar spectrum. The broadband character of the proposed scheme enables the use of an unreduced spatial resolution with an intermittent update of gaseous transmissions and interpolation weights, thus ensuring a full response of longwave radiation to rapidly varying cloudiness and temperature fields. This is in contrast to the mainstream strategy, where very accurate and expensive radiative transfer calculations are performed infrequently, often with reduced spatial resolution. The approach proposed here provides a much better balance between errors coming from the radiation scheme itself and from the intermittency strategy. The key achievement, ensuring a good scalability of the scheme, is a computational cost essentially linear in the number of layers, with straightforward inclusion of scattering as an additional bonus. [ABSTRACT FROM AUTHOR]

Spectral integration is the most time consuming part of solar radiative transfer codes used in numerical weather prediction. Routinely used approaches usually incline to one of two extremes - expensive and very accurate correlated k-distribution method made affordable by doing radiative transfer calculations with reduced temporal and/or spatial resolution, or cheaper but less accurate broadband approach affordable at every grid-point and time-step. Both approaches have their pros and cons, but hybrid solutions do not seem very promising. The presented work improves accuracy of full spectrum broadband approach by parameterizing secondary saturation of gaseous absorption, optical saturation of Rayleigh scattering and of cloud absorption as well as non-random gas-cloud spectral overlap. In order to isolate the problem of spectral integration from other approximations, one builds a narrowband reference using the same delta-two stream framework as the broadband scheme. Using this reference reveals the surprising fact that saturation effect of cloud absorption for one single layer and for the whole solar spectrum can be parameterized in a rather compact way, with one simple formula for liquid clouds and one for ice clouds. One then introduces the concept of effective cloud optical depth, which extends the applicability of parameterized cloud optical saturation to multi-layer cases, accommodating also effects of gas-cloud spectral overlap in the near-infrared. A scheme with all the above parameterizations indeed pushes accuracy limits of broadband approach to the level where a single shortwave interval can be used. This opens the possibility to reduce costs by using selective intermittency, where slowly evolving gaseous transmissions are updated on the timescale of hours, while quickly varying cloud optical properties are recomputed at every model time-step. In a companion article it will be demonstrated that the above core strategy is applicable also to thermal radiative transfer, with perhaps even better cost effectiveness there. [ABSTRACT FROM AUTHOR]

Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1 Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1 Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1 Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1 -/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1 Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1 +/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1 -/- mice with Jag1 Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1 -/- mice with Jag1 +/+ lymphocytes. Finally, the Jag1 Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS., (© 2024. The Author(s).)