Deciding absorption

We characterize absorption in finite idempotent algebras by means of J\'onsson absorption and cube term blockers. As an application we show that it is decidable whether a given subset is an absorbing subuniverse of an algebra given by the tables of its basic operations

Transmission channels for light in absorbing random media: from diffusive to ballistic-like transport

While the absorption of light is ubiquitous in nature and in applications, the question remains how absorption modifies the transmission channels in random media. We present a numerical study on the effects of optical absorption on the maximal transmission and minimal reflection channels in a two-dimensional disordered waveguide. In the weak absorption regime, where the system length is less than the diffusive absorption length, the maximal transmission channel is dominated by diffusive transport and it is equivalent to the minimal reflection channel. Its frequency bandwidth is determined by the underlying quasimode width. However, when the absorption is strong, light transport in the maximal transmission channel undergoes a sharp transition and becomes ballistic-like transport. Its frequency bandwidth increases with absorption, and the exact scaling varies with the sample's realization. The minimal reflection channel becomes different from the maximal transmission channel and becomes dominated by absorption. Counterintuitively, we observe in some samples that the minimum reflection eigenvalue increases with absorption. Our results show that strong absorption turns open channels in random media from diffusive to ballistic-like.Comment: 11 pages, 7 figure

Intestinal Absorption

This is the edited transcript of a Witness Seminar held at the Wellcome Institute for the History of Medicine,in London, on 9 February 1999. First published by the Wellcome Trust, 2000. ©The Trustee of the Wellcome Trust, London, 2000.All volumes are freely available online at: www.history.qmul.ac.uk/research/modbiomed/wellcome_witnesses/Annotated and edtied transcript of a Witness Seminar held on 9 February 1999. Introduction by Sir Christopher Booth.Annotated and edtied transcript of a Witness Seminar held on 9 February 1999. Introduction by Sir Christopher Booth.Annotated and edtied transcript of a Witness Seminar held on 9 February 1999. Introduction by Sir Christopher Booth.Annotated and edtied transcript of a Witness Seminar held on 9 February 1999. Introduction by Sir Christopher Booth.A record of a meeting chaired by Lord Turnberg that brought together those from laboratory research and medical practice to discuss some of the key aspects of intestinal absorption, including work on basic physiological mechanisms and techniques, such as the discovery of dedicated transport systems and their localization, and their clinical impact in intestinal disorders and oral rehydration therapy. Participants include: Sir Christopher Booth, Dr Richard Boyd, Professor Ramsey Bronk, Professor Hermon Dowling, Professor Michael Gardner, Dr Michael Hellier, Dr Roy Levin, Professor Richard Naftalin, Professor Timothy Peters, Professor John Walker-Smith and Professor Oliver Wrong. Christie D A, Tansey E M. (eds) (2000) Intestinal absorption, Wellcome Witnesses to Twentieth Century Medicine, vol. 8. London: The Wellcome Trust.The Wellcome Trust is a registered charity, no. 210183

Synopsis of Mid-latitude Radio Wave Absorption in Europe

Radio wave absorption data covering almost two years from Europe to Central Asia are presented. They are normalized by relating them to a reference absorption. Every day these normalized data are fitted to a mathematical function of geographical location in order to obtain a daily synopsis of radio wave absorption. A film of these absorption charts was made which is intended to reveal movements of absorption or absorption anomaly. In addition, radiance (temperature) data from the lower D-region are also plotted onto these charts

Soliton absorption spectroscopy

We analyze optical soliton propagation in the presence of weak absorption lines with much narrower linewidths as compared to the soliton spectrum width using the novel perturbation analysis technique based on an integral representation in the spectral domain. The stable soliton acquires spectral modulation that follows the associated index of refraction of the absorber. The model can be applied to ordinary soliton propagation and to an absorber inside a passively modelocked laser. In the latter case, a comparison with water vapor absorption in a femtosecond Cr:ZnSe laser yields a very good agreement with experiment. Compared to the conventional absorption measurement in a cell of the same length, the signal is increased by an order of magnitude. The obtained analytical expressions allow further improving of the sensitivity and spectroscopic accuracy making the soliton absorption spectroscopy a promising novel measurement technique.Comment: 9 pages, 7 figures

The effect of surface heterogeneity on cloud absorption estimates

This study presents a systematic and quantitative analysis of the effect of inhomogeneous surface albedo on shortwave cloud absorption estimates. We used 3D radiative transfer modeling over a checkerboard surface albedo to calculate cloud absorption. We have found that accounting for surface heterogeneity enhances cloud absorption. However, the enhancement is not sufficient to explain the reported difference between measured and modeled cloud absorption