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  • 1
    Electronic Resource
    Electronic Resource
    Infrared spectroscopy of HX (X=Br,Cl) adsorbed on LiF(001): Alignment and orientation (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 7003-7018 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The infrared spectra of HBr and HCl on LiF(001) single crystal surfaces were measured as a function of coverage at temperatures ≤83 K using Fourier-transform infrared (FTIR) spectroscopy. For each hydrogen halide three different spectral features could be distinguished. At low coverages broad absorptions centered at 2265±20 cm−1 (HBr) and at 2515±20 cm−1 (HCl) were observed. These absorptions were attributed to molecules hydrogen-bonded to F− anions of the surface, the angle between the molecular axis and the surface being 21±5° for HBr and 19±5° for HCl as determined from experiments employing polarized infrared radiation. Hydrogen bonding was evidenced by: (i) redshifts with respect to the gas phase (∼300 cm−1), (ii) broad infrared absorption (FWHM: 265±25 cm−1 for HBr, 295±15 cm−1 for HCl), and (iii) enhancement of the infrared absorption intensity compared to the gas phase by more than one order of magnitude for both HBr and HCl. With increasing coverage a second absorption was observed before the first one saturated (HBr:ν=2461±5 cm−1, FWHM=75±10 cm−1; HCl: ν=2763±5 cm−1, FWHM=80±10 cm−1). This absorption was attributed to molecules adsorbed in a second layer. The smaller redshift and spectral width for the second layer were consistent with weaker hydrogen bonding, probably to the halogen of molecules adsorbed in the first layer. Further increase in coverage resulted in the appearance of the well-known doublet absorptions due to formation of solid. Coadsorption of HBr and HCl, as well as experiments under adsorption–desorption equilibrium conditions, confirmed that the first and second layers could coexist. The isotherms could best be understood on the assumption of a repulsive interaction within the first layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460234
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  • 2
    Electronic Resource
    Electronic Resource
    Photodissociation dynamics of (NO)2 on LiF(001): Characterization of vibrationally excited NO fragments (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 6308-6326 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of adsorbed NO dimers on LiF(001) was studied in the monolayer regime at 248 nm using resonantly enhanced multiphoton ionization (REMPI) and Fourier transform infrared (FTIR) absorption spectroscopy. Vibrationally excited NO photofragments were observed in v'=0–9. The vibrational energy distribution was found to have a maximum at v'=0 and a second region of substantial population between v'=2 and 9. The rotational and translational energy distributions of the photofragments showed no major change with vibrational excitation. By contrast, the translational energy displayed a systematic increase with increasing rotational excitation. Photodissociation at 1 ML (NO)2 coverage yielded average vibrational, rotational, and translational energies of 0.48, 0.05, and 0.13 eV, respectively, in the NO fragments. The vibrational and rotational energy distributions of the fragments were unchanged for 0.06 ML, while the translational energy increased by approximately 30% in going to this lower coverage. The angular distribution was peaked in the normal direction at both coverages. The results are interpreted in terms of an excitation/deexcitation mechanism, for which the observed energy distributions can be rationalized by assuming differing equilibrium geometries between the ground and excited states of the adsorbed dimer. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469078
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  • 3
    Electronic Resource
    Electronic Resource
    Photodissociation of nitrogen dioxide adsorbed on lithium fluoride (001) (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 10983-10994 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100205a070
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  • 4
    Electronic Resource
    Electronic Resource
    Evolution and Systematic Significance of Polyploidy (1976)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Ecology, Evolution, and Systematics 7 (1976), S. 209-234 
    Details
    ISSN: 0066-4162
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.es.07.110176.001233
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  • 5
    Electronic Resource
    Electronic Resource
    The Karyotype in Systematics (1971)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Ecology, Evolution, and Systematics 2 (1971), S. 327-368 
    Details
    ISSN: 0066-4162
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.es.02.110171.001551
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative analysis of diploid translocation heterozygotes: test of models and equations (1986)
    Springer
    Theoretical and applied genetics 71 (1986), S. 600-606 
    Details
    ISSN: 1432-2242
    Keywords: Translocation heterozygote ; Chromosome pairing models ; Equations ; Quantitative analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Equations have been derived for two different models of chromosome pairing and chiasmata distribution. The first model represents the normal condition and assumes complete synapsis of homologous bivalents and the arms of interchange quadrivalents. This is followed by a nonrandom distribution of chiasmata among bivalents and multivalents such that each bivalent or bivalent-equivalent always has at least one chiasma. Univalents occur only as part of a III, I configuration at diakinesis or metaphase I. The second model assumes that a hologenomic mutation is present in which all chromosomes of a genome are equally affected. Two different assumptions can be made for such a mutation, and both give the same results: (1) homologous or homoeologous chromosome arms may be randomly paired or unpaired, but synapsis always leads to a crossover; (2) homologous or homoeologous arms always pair, but chiasmata are randomly distributed among the arms. The meiotic configurations at diakinesis or metaphase I are the same for both assumptions. Meiotic configurations of normal diploid interchange heterozygotes show good agreement with numbers predicted by the equations for nonrandom chiasmata distribution among configurations. Inter-specific hybrids with supernumerary chromosomes produced meiotic configurations frequencies in agreement with predictions of equations for random chiasmata distribution, but a hybrid without supernumeraries fitted the nonrandom expectations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264263
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  • 7
    Electronic Resource
    Electronic Resource
    Colchicine induced quadrivalent formation in Helianthus: evidence of ancient polyploidy (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 219-222 
    Details
    ISSN: 1432-2242
    Keywords: Helianthus ; Colchicine ; Induced quadrivalents ; Cryptic polyploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The premeiotic treatment of microsporocytes of Helianthus annuus and H. laciniatus (x= 17) results in the formation of multivalent chromosome configurations at meiosis in these ‘diploid’ species. This is interpreted to mean that colchicine has disrupted the normal attachment of genomes to the nuclear membrane and allowed synapsis of the ancestral genomes, indicating the polyploid origin of these ‘diploid’ species. This technique should be of importance in generating intergenomal recombination in classical allopolyploid agronomic species because it could produce new genotypic combinations normally impossible to obtain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303768
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  • 8
    Electronic Resource
    Electronic Resource
    Heterochromatin differentiation and phylogenetic relationship of the A genomes in diploid and polyploid wheats (1989)
    Springer
    Theoretical and applied genetics 77 (1989), S. 84-94 
    Details
    ISSN: 1432-2242
    Keywords: Triticum ; Heterochromatin ; Wheat evolution ; Diploids ; Polyploids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Heterochromatin differentiation, including band size, sites, and Giemsa staining intensity, was analyzed by the HKG (HCl-KOH-Giemsa) banding technique in the A genomes of 21 diploid (Triticum urartu, T. boeoticum and T. monococcum), 13 tetraploid (T. araraticum, T. timopheevi, T. dicoccoides and T. turgidum var. Dicoccon, Polonicum), and 7 cultivars of hexaploid (T. aestivum) wheats from different germplasm collections. Among wild and cultivated diploid taxa, heterochromatin was located mainly at centromeric regions, but the size and staining intensity were distinct and some accessions' genomes had interstitial and telomeric bands. Among wild and cultivated polyploid wheats, heterochromatin exhibited bifurcated differentiation. Heterochromatinization occurred in chromosomes 4At and 7At and in smaller amounts in 2At, 3At, 5At, and 6At within the genomes of the tetraploid Timopheevi group (T. araraticum, and T. timopheevi) and vice versa within those of the Emmer group (T. dicoccoides and T. turgidum). Similar divergence patterns occurred among chromosome 4Aa and 7Aa of cultivars of hexaploid wheat (T. aestivum). These dynamic processes could be related to geographic distribution and to natural and artifical selection. Comparison of the A genomes of diploid wheats with those of polyploid wheats shows that the A genomes in existing diploid wheats could not be the direct donors of those in polyploid wheats, but that the extant taxa of diploids and polyploids probably have a common origin and share a common A-genomelike ancestor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292321
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  • 9
    Electronic Resource
    Electronic Resource
    The effect of speed and load changes on oxygen intake for equivalent power outputs during bicycle ergometry (1967)
    Springer
    European journal of applied physiology 24 (1967), S. 284-290 
    Details
    ISSN: 1439-6327
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Investigations of the effect of speed of pedalling and load changes on oxygen intake for equivalent power have been made on one high calibre athlete. It has been demonstrated that the oxygen intake at low power developed at high rates against small resistance is equivalent to that at much higher power developed at slower rates and against higher resistances. These results highlight the great disparity in method currently used by investigators to study physical working capability. Several limitations in the existing methodology in all rate determined work tests have been noted and some criteria for establishing a standard international methodology suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698204
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  • 10
    Electronic Resource
    Electronic Resource
    The potentiating effect of low oxygen tension exposure during training on subsequent cardiovascular performance (1968)
    Springer
    European journal of applied physiology 26 (1968), S. 164-179 
    Details
    ISSN: 1439-6327
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of exhaustive bicycle ergometer training in hypoxia (FIO2 0.110–0.125) on several cardiovascular parameters was measured in an Olympic oarsman by serial measurements made daily over a period of 3 months. The hypoxic training had a potentiating effect on ventilation and oxygen uptake both of which attained upper limiting values in all-out tests at the end of one month of training. Acid-base balance changes were measured from arterialized capillary blood and showed a decreasing negative base excess (BE) and low pH response to exhaustive exercise. It has been hypothesized that once maximum oxygen intake ability has been developed an additional training effect was shown either by an increasing buffering capacity to non-volatile acid or by improved oxygen transport at tissue level so that there was a diminished need for an exergonic process of the type glycogen to lactic acid. The effect of interposing normoxic training during the middle month of the whole exercise period negatively affected exhaustive tests in hypoxia but had much less effect on the rate of improvement in exhaustive normoxic tests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00699513
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