Blue, white, and red ocean planets - Simulations of orbital variations in flux and polarization colors

An exoplanet's habitability will depend strongly on the presence of liquid water. Flux and/or polarization measurements of starlight that is reflected by exoplanets could help to identify exo-oceans. We investigate which broadband spectral features in flux and polarization phase functions of reflected starlight uniquely identify exo-oceans. We compute total fluxes F and polarized fluxes Q of starlight reflected by cloud-free and (partly) cloudy exoplanets, for wavelengths from 350 to 865 nm. The ocean surface has waves composed of Fresnel reflecting wave facets and whitecaps, and scattering within the water body is included. Total flux F, polarized flux Q, and degree of polarization P of ocean planets change color from blue, through white, to red at phase angles alpha ranging from 134-108 deg for F, and from 123-157 deg for Q, with cloud coverage fraction fc increasing from 0.0 to 1.0 for F, and to 0.98 for Q. The color change in P only occurs for fc ranging from 0.03-0.98, with the color crossing angle alpha ranging from 88-161 deg. The total flux F of a cloudy, zero surface albedo planet can also change color, and for fc=0.0, an ocean planet's F will not change color for surface pressures ps > 8 bars. Polarized flux Q of a zero surface albedo planet does not change color for any fc. The color change of P of starlight reflected by an exoplanet, from blue, through white, to red with increasing alpha above 88 deg, appears to identify a (partly) cloudy exo-ocean. The color change of polarized flux Q with increasing alpha above 123 deg appears to uniquely identify an exo-ocean, independent of surface pressure or cloud fraction. At the color changing phase angle, the angular distance between a star and its planet is much larger than at the phase angle where the glint appears in reflected light. The color change in polarization thus offers better prospects for detecting exo-oceans.Comment: Accepted for publication in Astron. Astrophys; multicolumn versio

A novel strategy to reduce dizziness:Applying a prognosis-oriented approach in older patients in general practice

Horst, H.E. van der [Promotor]Maarsingh, O.R. [Copromotor]Wouden, J.C. van der [Copromotor

Metabolism: flow and contractility of the Langendorff heart

This thesis reviews current literature and describes experimental studies on the regulation and modification of coronary flow and contractility in isolated rat hearts. In chapter I and introduction is given to the problems of fatty acid toxicity and myocardial function. Coronary flow rate and pump function of the myocardium are mainly determined by the contractile status of vascular smooth muscle cells and cardiac striated muscle cells, respectively. Therefore in chapters II and III morphological and (ultra)structural aspects of both types of cells have been described. In chapters IV and V functional and metabolic aspects of coronary circulation and contractility are illustrated. In both vascular smooth and cardiac striated muscle cells: (i) the intracellular calcium concentration is the main determinant of the contractile status of actomyosin, (ii) contraction takes place after the action potentialinduced calcium-influx through the plasmamembrane and calcium release from intracellular stores (sarcoplasmic reticulum, mitochondria), (iii) relaxation is achieved after reduction of the cytoplasmic calcium level by calcium-pump systems in the plasmamembrane, sarcoplasmic reticulum and mitochondria, (iv) calcium-ions trigger the coupling between the contraction-relaxation cycle with energy metabolism since glycogenolysis and lipolysis are both stimulated by calcium

Peaks of Joy, Valleys of Despair: The History of the Syracuse University Library from 1871 to 1907

Drawing on a variety of sources, Starn presents engaging samples of life in the early days of the Syracuse University Library

Preface: A Special Stephen Crane Issue

One of the great pleasures of coming to a new library, as I did to Syracuse last March, is the joy of discovering particularly strong but unexpected collections. The Leopold von Ranke holdings, the Margaret Bourke,White collection, and the Belfer Audio Archives are just a few of the great strengths of the Syracuse University Libraries and its special collections

Transboundary Air Pollution in Europe: An Interactive Multicriteria Tradeoff Analysis

In this paper. the acid rain problem in Europe is discussed, stressing the transboundary tradeoffs between abatement costs of sulphur emission reduction and corresponding deposition levels in the different countries. An interactive decision support methodology is proposed which utilizes a powerful nonlinear multicriteria software package to evaluate various scenarios and tradeoffs. The concepts are illustrated using previously published data. The results from the tradeoff analysis show that reasonable deposition levels can be reached with limited transfers of funds between countries. The extent of these transfers can be controlled by selecting appropriate target levels for the criteria across countries

Scattering matrices and expansion coefficients of Martian analogue palagonite particles

We present measurements of ratios of elements of the scattering matrix of Martian analogue palagonite particles for scattering angles ranging from 3 to 174 degrees and a wavelength of 632.8 nm. To facilitate the use of these measurements in radiative transfer calculations we have devised a method that enables us to obtain, from these measurements, a normalized synthetic scattering matrix covering the complete scattering angle range from 0 to 180 degrees. Our method is based on employing the coefficients of the expansions of scattering matrix elements into generalized spherical functions. The synthetic scattering matrix elements and/or the expansion coefficients obtained in this way, can be used to include multiple scattering by these irregularly shaped particles in (polarized) radiative transfer calculations, such as calculations of sunlight that is scattered in the dusty Martian atmosphere.Comment: 34 pages 7 figures 1 tabl