Über den statischen Regelfaktor der menschlichen Pupille
SummaryThe static regulation factor of the pupil servosystem in man, as dependent on the intensity of the light-stimulus, was calculated. Data were collected from own experiments, in which the whole field of view of one eye was homogeneously illuminated by white light. For these calculations the author developped a suitable definition of the regulation factor, using ordinary and partial differential quotients. The optimum of the regulation factor was found to be 2/3 at a luminance of 200 abs, i.e., at this point 1/3 of the slight variations in light intensity are compensated.
Peripheral and central contribution to the pupillary reflex control in amphibians: pupillographic and theoretical considerations
The amphibian pupillary response is mediated by two mechanisms. One is restricted to the iris itself, the other involves the central nervous system. In the present study we investigated the dynamic of the pupillary response and separated the parts by experiments with lesions of the optic and oculomotor nerve. The pupillary response of urodeles is comparable to that in other vertebrates. Differences are observable in amplitude and time course. Furthermore there are no binocular summation or consensual reactions. The central control of the pupillary response increases amplitude and velocity of the pupillary response in sudden luminance changes, compared to the pure iris related reaction. The separation of central and peripheral pupillary reflex control was shown more quantitatively through the introduction of a theoretical model. The investigation of the dark response gives evidence that there is no dilatator pupillae in urodele amphibians, since comparison to results in anuran species show that this is not a general feature in amphibians.
Physical Processes in Inorganic Scintillators
BASIC PRINCIPLES AND PROCESSES Physical Mechanism of Scintillation Creation of Electron Hole Pairs Excitation and Emission of Luminescence Centers Scintillation Materials Halides Oxides and Oxide Systems Chalcogenides Glasses Interaction of Ionizing Radiation with Scintillators High Energy Photons Charged Particles Neutral Particles General Characteristics of Inorganic Scintillators Light Yield Duration of Scintillation Pulse Afterglow Temperature Response Optical Properties Radiation Hardness Density Emission Spectra Mechanical and Chemical Properties Physical Parameters Cost Consideration Scintillator Requirements in Various Applications High Energy Physics Intermediate Energy Physics Positron Emission Tomography Gamma Spectroscopy Energy Resolution Intrinsic Scintillator Resolution Nonproportional Response Time Resolution Low Energy Quanta and Electrons CONVERSION OF ELECTRONIC EXCITATIONS IN SOLIDS Charge Carrier Behaviors Delta Rays Secondaries Excitation of Luminescence Centers Effect of Ionization Density Energy Losses Simple Phenomenological Model Plasmon Model Polaron Model Scintillation Yield Spectra Vacuum Ultraviolet Region Ultrasoft X-Rays X-Rays Gamma Rays Heavy Ionizing Particles INTRINSIC LUMINESCENCE OF INORGANIC SCINTILLATORS Excitonic Luminescence Alkali Halide Crystals Alkaline-Earth Fluorides Ternary Halide Compounds Excitonic-Like Luminescence Cesium Iodide Tungstate and Molybdate Phosphors Core-to-Valence Transitions First Evidence for Radiative Core-to-Valence Transitions Excitation Spectra Emission Spectra Experiment Theory Luminescence Kinetics Experimental Theoretical Investigations Temperature Dependence of Luminescence Parameters Conditions of Detection Prospects for Research EXTRINSIC LUMINESCENCE OF INORGANIC SCINTILLATORS Thallium-Activated Halide Scintillators Crystals with NaCl-Type Structure Crystals with CsCl-Type Structure Other Thallium-Based and Thallium-Doped Crystals Crystals Containing Other ns2 Ions Bismuth Germanate (BGO) Sodium-Activated Cesium Iodide Rare-Earth-Activated Crystals General Considerations Europium-Activated Crystals Cerium-Activated Compounds Preliminary Comments LaF3-CeF3 Systems Cerium Chloride Barium Fluoride Gadolinium-Containing Crystals Lu- and Y-Containing Crystals Nd- and Pr-Activated Crystals DEFECT FORMATION BY IONIZING RADIATION Effect on Scintillator Characteristics Mechanisms of Defect Formation Efficiency of Defect Production Geometrical Factor Separation between F and H Centers Temperature Dependence of Production Efficiency Role of Halogen Ion Impurities Effect of Cation Impurities Formation Time of F-H Pairs Closing Comments References Index