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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 46 (1999), S. 131-136 
    ISSN: 1420-9098
    Keywords: Key words:Vespula, Polistes, Vespidae, foraging, resource choice.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The role of visual cues provided by resident wasps on resource choice by yellowjacket and paper wasp foragers was investigated. Large spring queen yellowjackets and small early season yellowjacket foragers (Vespula germanica, Vespula maculifrons, and Vespula vidua) were extracted in hexane to remove odors and posed as though feeding at petri dish feeders bearing daisy-like flower models, equipped with microcapillary feeding tubes, and containing 1:3 honey:water solution. An array of five feeders was presented to foragers at a suburban and a woodland site in Saratoga Springs, New York. The visual cues provided by resident wasps influenced resource choice by approaching social wasp foragers. Vespula germanica, an introduced yellowjacket species that tends to dominate at rich resources, was the only wasp visiting the suburban feeders. Foragers of this species preferentially fed on feeders and flowers with posed wasps and fed most often next to large wasps. Polistes fuscatus foragers at the woodland site similarly preferred to feed on occupied feeders and flowers. Vespula maculifrons and V. consobrina preferentially visited unoccupied feeders. Individual V. maculifrons, V. consobrina and V. vidua foragers that landed on occupied feeders all preferentially visited unoccupied flowers on those feeders. Vespula vidua and V. flavopilosa foragers did not demonstrate a feeder preference based on the presence/absence of posed wasps. Vespula consobrina foragers that visited occupied feeders preferred those occupied by extracted V. maculifrons queens and workers; no other wasps showed species based landing preferences.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The chemical educator 3 (1998), S. 1-11 
    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An undergraduate instrumental analysis laboratory exercise is presented for the characterization of light emission generated using electrochemiluminescence (ECL). ECL involves the electrochemical generation of excited states and as such is a sensitive probe of electrochemical, electron-transfer and energy-transfer processes at electrified interfaces. An objective of this experiment is to have students develop an understanding of the mechanisms and factors affecting ECL. Also, this exercise gives students experience in coupling two powerful analytical techniques: electrochemistry and spectroscopy. With the recent development of ECL technology for use in clinical diagnostics applications, this exercise also facilitates discussions on the importance of basic research and the practical aspects of taking a technology from the bench top to commercial reality.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1420-9098
    Keywords: Hymenoptera ; social wasps ; Polybia ; prey capture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polybia sericea (Hymenoptera: Vespidae) prey foraging was studied by following individual foragers as they hunted in the field, by observing how wasps handled prey once they had captured it, and by observing wasps as they returned to the nest with prey. Wasps were most likely to forage for prey between 0700 and 1300 hours and between 1600 and 1700 hours. The prey foraging sequence consisted of the behaviours high flight, search, touch, land, groom, walk, bite and malaxate. Captured small prey were malaxated and carried to the nest. Wasps removed the gut from large prey and dragged the meat up a twig or grass stem. A load of the meat was then bitten off and malaxated; the remainder was cached while the wasp made an orientation flight and returned to the nest. The forager returned within minutes for the remainder of the prey. Experiments demonstrated that caching the prey remains above the ground rather than close to the ground, where the prey are generally captured, reduces the chance that the prey will be found and expropriated by ants.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Economic theory 1 (1991), S. 231-249 
    ISSN: 1432-0479
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Summary We characterize continuous representability of preference relations by multiplicative functions and by certain polynomial functions, on connected topological spaces. Our methods show that the same Continuity Principle that yielded additive utility representations in earlier work applies much more generally.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 70 (1992), S. 735-739 
    ISSN: 1432-1440
    Keywords: Kidney ; Calcium ; Phosphate ; Sodium ; Caries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clearance studies were performed for 2 days in two groups of age-matched young female volunteers: those with low caries prevalence and those with high caries prevalence. Both groups were kept on a low-calcium diet for 1 week and received 0.5 g calcium at the beginning of the second day. In both groups, glomerular filtration rate, urinary flow rate and renal excretions of sodium, calcium, and phosphate were subject to significant circadian variations. In both groups the administration of calcium led to a significant increase in renal excretion of sodium and calcium and a significant decrease in that of phosphate. On the first day, calcium excretion was significantly greater in those with low caries prevalence than in those with high caries prevalence, pointing to altered calcium homeostasis in this group.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0949-2925
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 386-397 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have studied the ultraviolet laser-induced desorption of NO molecules from an epitaxial film of NiO(100) on Ni(100) for pulse durations of 550 fs and at a photon energy of 3.95 eV. For applied laser intensities up to 450 MW/cm2, the highest intensities employed in this work, a linear dependence of the desorption yield on the laser intensity is observed. A desorption cross section of (1.9±0.3)⋅10−17 cm2 is then derived. The molecules are detected with rovibrational state selectivity by (1+1)-REMPI via the A 2Σ+(v′=0,1,2,3)←X 2Π(v″=0,1,2,3) γ-band transitions. The rotational population distributions are nonthermal, with rotational temperatures of about 290 K at low and of about 770 K at high rotational energies. The relative populations in the 2Π1/2 and 2Π3/2 fine-structure states and of the Λ-doublet states are examined for the given set of (v″,J″) quantum numbers. The vibrational states v″〉0 are significantly populated approaching vibrational temperatures of 3800 K. Velocity distributions of the desorbed molecules are measured for individual rovibrational states. Bimodal distributions with a distinct rotational-translational coupling are observed. Further, molecules desorbing in the excited fine-structure state 2Π3/2 show a higher velocity than those desorbing in 2Π1/2. The results are compared with earlier ones obtained for the same system with nanosecond desorption pulses at hν=6.4 eV. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Magnetic and specific-heat studies of U2T2X compounds show a frequent occurrence of the γ enhancement in conjunction with the onset of antiferromagnetic ordering. The largest value of 830 mJ/mol K2 was observed in U2Pt2In, which is nonmagnetic down to 1.2 K. Variations of electronic structure are documented by optimized relativistic LCAO calculation.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We present the first photoelectron spectrometry experiment on a singly charged ion beam. Taking advantage of the high photon flux emitted in the undulator SU6 of Super-ACO, we have measured photoelectron spectra produced in the resonant photoionization of Ca+ ions at 33.2-eV photon energy. The success of this experiment depended strongly on the photon flux available. We demonstrate the capability of photoelectron spectrometry to precisely calibrate the photon spectrum emitted in the undulator.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Small cantilevers allow for faster imaging and faster force spectroscopy of single biopolymers than previously possible because they have higher resonant frequencies and lower coefficients of viscous damping. We have used a new prototype atomic force microscope with small cantilevers to produce stable tapping-mode images (1 μm×1 μm) in liquid of DNA adsorbed onto mica in as little as 1.7 s per image. We have also used these cantilevers to observe the forced unfolding of individual titin molecules on a time scale an order of magnitude faster than previously reported. These experiments demonstrate that a new generation of atomic force microscopes using small cantilevers will enable us to study biological processes with greater time resolution. Furthermore, these instruments allow us to narrow the gap in time between results from force spectroscopy experiments and molecular dynamics calculations. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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