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61.
EXTRARETINAL PHOTORECEPTION IN LIZARDS 总被引:1,自引:0,他引:1
Abstract— In lizards both photoperiodic photoreception and entrainment (synchronization) of the biological clock by environmental light cycles can be accomplished by extraretinal photoreceptors. Testicular size and spermatogenic activity in the green anole, Anolis carolinensis , is maintained under long (14 h) photoperiods in the summer in both sighted and blinded lizards whereas short days (6h) cause testicular regression. In the fall, long photoperiods cause testicular recrudescence and maturation in blinded and blinded-parietalectomized anoles as well as in sighted anoles.
Extraretinal photoreceptors can mediate entrainment of the circadian locomotor rhythm in every lizard species examined to date (8 species). The photosensory pineal complex in lizards (pineal organ and parietal eye) may not be involved in entrainment; in any case, its removal does not prevent entrainment of blinded lizards. Localization experiments have shown that the brain is the site of the extraretinal receptors mediating entrainment. The lateral eyes can also contribute to entrainment. In some species, but not all, blinding alters the pattern of the entrained activity rhythm. The free-running activity rhythms of two species of lizards exposed to continuous illumination respond very differently to blinding; these experiments yield insight into the mechanisms of entrainment in the two species as well as showing that caution must be observed when generalizing about the role of retinal and extraretinal receptors not only among different vertebrate classes but also among species of the same class. 相似文献
Extraretinal photoreceptors can mediate entrainment of the circadian locomotor rhythm in every lizard species examined to date (8 species). The photosensory pineal complex in lizards (pineal organ and parietal eye) may not be involved in entrainment; in any case, its removal does not prevent entrainment of blinded lizards. Localization experiments have shown that the brain is the site of the extraretinal receptors mediating entrainment. The lateral eyes can also contribute to entrainment. In some species, but not all, blinding alters the pattern of the entrained activity rhythm. The free-running activity rhythms of two species of lizards exposed to continuous illumination respond very differently to blinding; these experiments yield insight into the mechanisms of entrainment in the two species as well as showing that caution must be observed when generalizing about the role of retinal and extraretinal receptors not only among different vertebrate classes but also among species of the same class. 相似文献
62.
Michael B. Stringer Dennis J. Underwood John H. Bowie Colin E. Allison Kevin F. Donchi Peter J. Derrick 《Journal of mass spectrometry : JMS》1992,27(3):270-276
Intramolecular 13C and 2H isotope effects have been measured for unimolecular losses of ethene (the McLafferty rearrangement) from metastable molecular ions of 2-ethyl-1-phenylbutanl-1-one, 3-ethylpentan-2-one and heptan-4-one. Primary and secondary deuterium isotope effects are observed at the γ-(terminal) and β-positions, respectively. Large primary 13C isotope effects occur at β-positions and for the y positions of γ-ethylpentan-2-one and heptan-4-one. The carbon isotope effects in the cases of the doubly isotopically labelled CH3COCH(C2H5)(13CH2CH3) and CD3COCD(C2D5)(13CD2CD3) are 1.17 (±0.01) and 1.04 (±0.01), respectively. All of these isotope effects are consistent with a stepwise mechanism in which more than one step is rate determining. 相似文献
63.
Burleson GR Faucett JA Fontenla CA Garnett RW Rawool MW Ditzler WR Hill D Hoftiezer J Johnson KF Lopiano D Shima T Shimizu H Spinka H Stanek R Underwood D Wagner R Yokosawa A Bhatia TS Glass G Hiebert JC Kenefick RA Nath S Northcliffe LC Damjanovich R Jarmer JJ Jeppesen RH Tripard GE 《Physical review letters》1987,59(15):1645-1648
64.
Bonner BE Buchanan JA Carey DC Clement JM Coleman RN Corcoran MD Cossairt JD Derevshchikov AA Grosnick DP Hill DA Imai K Lehar F de Lesquen A Lopiano D Luehring FC Kruk JW Kuroda K Maki T Makino S Masaike A Matulenko YA Meshchanin AP Michalowicz A Miettinen HE Miller DH Miyake K Mohammadzadeh AH Mutchler GS Nagamine T Nessi-Tedaldi F Nessi M Nurushev SB Nguyen C Ohashi Y Pauletta G Penzo A Phillips GC Read AL Roberts JB van Rossum L Salvato G Schiavon P Shima T Solovyanov VL Spinka HM 《Physical review letters》1988,61(17):1918-1921
65.
Bullock JP Carter E Johnson R Kennedy AT Key SE Kraft BJ Saxon D Underwood P 《Inorganic chemistry》2008,47(17):7880-7887
The oxidative electrochemistry of luminescent rhenium (I) complexes of the type Re(CO) 3(LL)Cl, 1, and Re(CO) 3(LL)Br, 2, where LL is an alpha-diimine, was re-examined in acetonitrile. These compounds undergo metal-based one-electron oxidations, the products of which undergo rapid chemical reaction. Cyclic voltammetry results imply that the electrogenerated rhenium (II) species 1 ( + ) and 2 ( + ) disproportionate, yielding [Re(CO) 3(LL)(CH 3CN)] (+), 7, and additional products. Double potential step chronocoulometry experiments confirm that 1 ( + ) and 2 ( + ) react via second-order processes and, furthermore, indicate that the rate of disproportionation is influenced by the basicity and steric requirements of the alpha-diimine ligands. The simultaneous generation of rhenium (I) and (III) carbonyl products was detected upon the bulk oxidation of 1 using infrared spectroelectrochemistry. The rhenium (III) products are assigned as [Re(CO) 3(LL)Cl 2] (+), 5; an inner-sphere electron-transfer mechanism of the disproportionation is proposed on the basis of the apparent chloride transfer. Chemically irreversible two-electron reduction of 5 yields 1 and Cl (-). No direct spectroscopic evidence was obtained for the generation of rhenium (III) tricarbonyl bromide disproportionation products, [Re(CO) 3(LL)Br 2] (+), 6; this is attributed to their relatively rapid decomposition to 7 and dibromine. In addition, the 17-electron radical cations, 7 ( + ), were successfully characterized using infrared spectroelectrochemistry. 相似文献
66.
Simulation specimens were used to model the fatigue behavior of outside-diameter-notched internally pressurized cylinders of alloy steel. Results from continuum mechanics and finite-element analyses are described for use in selection of simulation-test conditions. The effects of notch depth and residual stress on fatigue life are determined from the simulation tests. 相似文献
67.
I. P. Auer A. Beretvas E. Colton D. Hill K. Nield H. Spinka D. Underwood Y. Watanabe A. Yokosawa 《Physics letters. [Part B]》1977,70(4):475-478
We have measured the difference between the pp total cross-sections for parallel and anti-parallel longitudinal spin states at beam momenta of 3 and 6 GeV/c. These results, combined with our previous measurements, at lower momenta, are useful in clarifying a striking structure appearing at around 1.5 GeV/c. We have also measured for the first time, the spin-spin correlation parameter CLL (t) in pp elastic scattering at 6 GeV/c. We observe evidence for an exchange with A1-like quantum-numbers. 相似文献
68.
W. Manchot H. Gall J. König O. Scherer H. R. Ambler T. C. Sutton T. J. Drakeley H. Nicol P. Schuftan A. T. Larson C. W. Whittaker A. B. Lamb W. E. Vail P. Lebeau P. Marmasse J. I. Graham C. de la Condamine A. Thau J. Thorbun L. Wein H. Lent H. Kast H. Selle M. Nicloux S. H. Katz G. Wittig J. E. Underwood A. Krogh P. Brandt Rehberg Shigeru Nishi J. Johnston A. C. Walker 《Analytical and bioanalytical chemistry》1928,75(1-2):39-46
69.
Adams DL Akchurin N Belikov NI Bravar A Bystricky J Corcoran MD Cossairt JD Cranshaw J Derevschikov AA En'yo H Funahashi H Goto Y Grachov OA Grosnick DP Hill DA Iijima T Imai K Itow Y Iwatani K Krueger KW Kuroda K Lehar F de Lesquen A Lopiano D Luehring FC Maki T Makino S Masaike A Matulenko YA Meschanin AP Michalowicz A Miller DH Miyake K Nagamine T Nessi-Tedaldi F Nessi M Nguyen C Nurushev SB Ohashi Y Onel Y Patalakha DI Pauletta G Penzo A Read AL Roberts JB van Rossum L Rykov VL Saito N 《Physical review D: Particles and fields》1996,53(9):4747-4755
70.
Measurement of the analyzing power in the Primakoff process with a high-energy polarized proton beam
Carey DC Coleman RN Corcoran MD Cossairt JD Derevschikov AA Grosnick DP Hill D Imai K Konaka A Kuroda K Lehar F de Lesquen A Lopiano D Luehring FC Maki T Makino S Masaike A Matulenko YA Meschanin AP Michalowicz A Miller DH Miyake K Nagamine T Nakano T Nessi-Tedaldi F Nessi M Nguyen C Nurushev SB Ohashi Y Pauletta G Penzo A Phillips GC Read AL Roberts JB van Rossum L Salvato G Schiavon P Shima T Solovyanov VL Spinka H Stanek RW Takashima R Takeutchi F Tamura N Tanaka N Underwood DG Vasiliev AN 《Physical review letters》1990,64(4):357-360