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  • 1
    Electronic Resource
    Electronic Resource
    Picosecond mobilities of neat diamino poly(propylene imine) dendrimer DAB(CN)64 from a Raman study of its CN stretching fundamental (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 9230-9234 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The paper is based on mid-frequency Raman scattering data of neat diamino poly(propylene imine) dendrimer molecule DAB(CN)64; time correlation functions were obtained from a band profile analysis of its fundamental CN mode near 2246 cm−1 at four temperatures between 300 and 123 K; lattice relaxation processes were found to be governed by a stretched exponential modulation function with dispersion parameter α=0.90±0.05 (300 K) and 0.85 (123 K) and corresponding time constant τ0=0.78 and 1.15 ps, respectively. The results suggest that the fast fluctuations of the molecular environment of the CN end groups of the dendrimer system regain equilibrium by independent, parallel pathways with Poisson relaxation times τ that show a broader distribution at lower system temperatures. The results imply that the shape and width of the CN band contour are generated by a vibrational dephasing process in the intermediate modulation regime, under inseparable contributions of intra- and intermolecular oscillator–lattice coupling. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478846
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  • 2
    Electronic Resource
    Electronic Resource
    Multiple transcription factors of the FNR family in denitrifying Pseudomonas stutzeri: characterization of four fnr-like genes, regulatory responses and cognate metabolic processes (1999)
    Oxford BSL : Blackwell Science Ltd
    Molecular microbiology 33 (1999), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1999.01494.x
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  • 3
    Electronic Resource
    Electronic Resource
    Multiple transcription factors of the FNR family in denitrifying Pseudomonas stutzeri : characterization of four fnr-like genes, regulatory responses and cognate metabolic processes (1999)
    Oxford BSL : Blackwell Science Ltd
    Molecular microbiology 31 (1999), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Pseudomonas stutzeri is a facultative anaerobic bacterium with the capability of denitrification. In searching for regulators that control the expression of this trait in response to oxygen withdrawal, we have found an unprecedented multiplicity of four genes encoding transcription factors of the FNR family. The fnrA gene encodes a genuine FNR-type regulator, which is expressed constitutively and controls the cytochrome cbb3-type terminal oxidase (the cco operon), cytochrome c peroxidase (the ccp gene) and the oxygen-independent coproporphyrinogen III oxidase (the hemN gene), in addition to its previously demonstrated role in arginine catabolism (the arc operon). The fnr homologues dnrD, dnrE and dnrS encode regulators of a new subgroup within the FNR family. Their main distinctive feature is the lack of cysteine residues for complexing the [4Fe–4S] centre of redox-active FNR-type regulators. However, they form a phylogenetic lineage separate from the FixK branch of FNR proteins, which also lack this cysteine signature. We have studied the expression of the dnr genes under aerobic, oxygen-limited and denitrifying conditions. DnrD is a key regulator of denitrification by selective activation of the genes for cytochrome cd1 nitrite reductase and NO reductase. The dnrD gene is part of the 30 kb region carrying denitrification genes of P. stutzeri. Transcription of dnrD was activated in O2-limited cells and particularly strongly in denitrifying cells, but was not under the control of FnrA. In response to denitrifying growth conditions, dnrD was transcribed as part of an operon together with genes downstream and upstream of dnrD. dnrS was found about 9 kb upstream of dnrD, next to the nrdD gene for anaerobic ribonucleotide reductase. The transcription of dnrS required FnrA in O2-limited cells. Mutation of dnrS affected nrdD and the expression of ferredoxin I as an element of the oxidative stress response. The dnrE gene is part of the nar region encoding functions for respiratory nitrate reduction. We found the highest amount of dnrE transcripts in aerobically nitrate-challenged cells. The gene was transcribed from two promoters, P1 and P2, of which promoter P1 was under the control of the nitrate response regulator NarL. The multiplicity of FNR factors in P. stutzeri underlines the versatility of the FNR scaffold to serve for transcriptional regulation directed at anaerobic or nitrate-activated metabolic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1999.01302.x
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  • 4
    Electronic Resource
    Electronic Resource
    Prejudice Toward Immigrants (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of applied social psychology 29 (1999), S. 0 
    Details
    ISSN: 1559-1816
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Psychology
    Notes: In the present study, 4 variables (realistic threats, symbolic threats, intergroup anxiety, and negative stereotypes) were used to predict prejudice toward immigrants from Cuba, Mexico, and Asia in samples of students from states in the United States that are affected by immigration from these areas (Florida, New Mexico, and Hawaii, respectively). All 4 variables were significant (or marginally significant) predictors of attitudes toward these immigrant groups. Evidence is presented that the predictor variables are conceptually and empirically distinct. However, these variables do appear to be tied together by an underlying theme: They all concern threats to the in-group or its members. Some of the implications of the results for intergroup relations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1559-1816.1999.tb00107.x
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  • 5
    Electronic Resource
    Electronic Resource
    Evaluation of pediatric nephropathies by a computerized Urine Protein Expert System (UPES) (1999)
    Springer
    Pediatric nephrology 13 (1999), S. 900-906 
    Details
    ISSN: 1432-198X
    Keywords: Key words Proteinuria ; Knowledge-based system ; Expert system ; Evaluation ; Decision support
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A computerized Urine Protein Expert System (UPES) measuring creatinine, total protein, albumin, IgG, α1-microglobulin, α2-macroglobulin, and N-acetyl-β-D-glucosaminidase, together with urine dipstick testing for granulocyte esterase and hemoglobin pseudoperoxidase, and measurement of serum creatinine had been found to be useful in adults for differentiating between renal disorders. The objective of this study was to investigate UPES for identifying the different types of proteinuria and their underlying prerenal, glomerular, tubular, and postrenal causes in 146 children characterized by routine and invasive nephrological investigations. UPES proved to be a useful tool in pediatric renal patients after refinements were implemented in the program. Comparing UPES with the pediatric nephrologist’s interpretation of all available clinical and laboratory data, UPES diagnosed glomerulopathies in 46 (75%) of 61 patients. In a further 23% it suggested glomerular involvement by indicating either a disturbed glomerular permeability or increased excretion of albumin. Tubular proteinuria was correctly described by UPES in 23 (100%) patients with different tubulopathies. UPES revealed normal kidney function in all healthy children and all children with remission of renal disorders. Therefore, UPES can be regarded as a useful tool in the automated differentiation of renal diseases in children.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004670050724
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  • 6
    Electronic Resource
    Electronic Resource
    The β+-electron capture decay of 73Kr (1999)
    Springer
    The European physical journal 5 (1999), S. 143-150 
    Details
    ISSN: 1434-601X
    Keywords: PACS: 21.10.Hw Spin, parity, and isobaric spin – 23.20.Lv Gamma transitions and level energies – 23.40.Hc Relation with nuclear matrix elements and nuclear structure – 27.50.+e 59 ≤ A ≤ 89
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The β+– electron capture decay of 73Kr, produced at the ISOLDE CERN facility, has been studied by β-delayed proton and gamma emission. The established decay scheme involves 15 up to now unreported gamma emitting levels in 73Br. The total proton branching ratio has been measured to be 0.0025 ± 0.0003. From this work, a spin and parity 3/2− is assigned to the 73Kr ground state, on the basis of the allowed β branch to the 73Br Jπ= 1/2− ground state and the feeding of the 5/2+ level located at 286 keV in 73Br.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050270
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  • 7
    Electronic Resource
    Electronic Resource
    Beta decay of 61Ga (1999)
    Springer
    The European physical journal 5 (1999), S. 151-156 
    Details
    ISSN: 1434-601X
    Keywords: PACS: 21.10.Hw Spin, parity, and isobaric spin – 23.40.Hc Relation with nuclear matrix elements and nuclear structure – 27.50.+e 59 ≤ A ≤ 89
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The β decay of 61Ga to its mirror nucleus 61Zn has been measured for the first time by using on-line mass separation and β-delayed gamma-ray spectroscopy. The observed decay strength to the ground state implies superallowed character in accordance with the systematics of the mirror decays in the sd and fp shell. The β feedings observed to four excited states in 61Zn are consistent with earlier spin-parity assignments based on in-beam experiments. The ground-state spin and parity for 61Ga were determined to be 3/2−.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100500050271
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  • 8
    Electronic Resource
    Electronic Resource
    Applying Satellite Imagery to Triage Assessment of Ecosystem Health (1999)
    Springer
    Environmental monitoring and assessment 54 (1999), S. 205-227 
    Details
    ISSN: 1573-2959
    Keywords: AVHRR imagery ; coppice dunes ; desert rangelands ; irreversible degraded ; regional classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Considerable evidence documents that certain changes in vegetation and soils result in irreversibly degraded rangeland ecosystems. We used Advanced Very High Resolution Radiometer (AVHRR) imagery to develop calibration patterns of change in the Normalized Difference Vegetation Index (NDVI) over the growing season for selected sites for which we had ground data and historical data characterizing these sites as irreversibly degraded. We used the NDVI curves for these training sites to classify and map the irreversibly degraded rangelands in southern New Mexico. We composited images into four year blocks: 1988–1991, 1989–1992, and 1990–1993. The overlap in pixels classified as irreversibly degraded ranged from 42.6% to 84.3% in year block comparisons. Quantitative data on vegetation composition and cover were collected at 13 sites within a small portion of the study area. Wide coverage reconnaissance of boundaries between vegetation types was also conducted for comparisons with year block maps. The year block 1988–1991 provided the most accurate delineation of degraded areas. The rangelands of southern New Mexico experienced above average precipitation from 1990–1993. The above average precipitation resulted in spatially variable productivity of ephemeral weedy plants on the training sites and degraded rangelands which resulted in much smaller areas classified as irreversibly degraded. We selected imagery for a single year, 1989, which was characterized by the absence of spring annual plant production in order to eliminate the confounding effect of reflectance from annual weeds. That image analysis classified more than 20% of the rangelands as irreversibly degraded because areas with shrub-grass mosaic were included in the degraded classification. The single year image included more than double the area classified as irreversibly degraded by the year blocks. AVHRR imagery can be used to make triage assessments of irreversibly degraded rangeland but such assessment requires understanding productivity patterns and variability across the landscapes of the region and careful selection of the years from which imagery is chosen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005876220078
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  • 9
    Electronic Resource
    Electronic Resource
    Ants as Indicators of Exposure to Environmental Stressors in North American Desert Grasslands (1999)
    Springer
    Environmental monitoring and assessment 54 (1999), S. 143-171 
    Details
    ISSN: 1573-2959
    Keywords: environmental stressors ; exposure indicators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The relative abundance of ant species was measured by pit-fall trapping at 44 sites in southern New Mexico and southeastern Arizona, U.S.A.. Sites were selected for study based on documentation of a history of disturbance or protection from disturbance, exposure to varying intensities of livestock grazing, dominance by an exotic species of plant and vegetation change resulting from disturbance or restoration efforts. Ant community composition, relative abundances of species, and species richness were the same on disturbed and undisturbed sites. None of the metrics based on hypothesized responses of ants to disturbance clearly distinguished between disturbed and undisturbed sites. Ant communities on sites where restoration efforts have resulted in distinct differences in vegetative cover and composition were similar to the ant communities on degraded unrehabilitated sites on the same soil type. Ant communities in riparian cottonwood gallery forests in Arizona and New Mexico were similar but differed from the assemblages in exotic salt cedar and native ash riparian woodlands. Ant species exhibited remarkable resistance to human-induced disturbances in these rangeland areas. In grasslands dominated by the South African grass, Eragrostis lehmanniana Nees, large seed harvesting ants, Pogonomyrmex spp., were greatly reduced in abundance compared to native grasslands. Other ant metrics were not different in E. lehmanniana grasslands and native grasslands. We conclude that ants cannot be used as indicators of exposure to stress, ecosystem health or of rehabilitation success on rangeland ecosystems. Ants are also not useful indicators of faunal biodiversity in rangeland ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005858918860
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