421 research outputs found
Cloning and expression of the levanase gene in Alcaligenes eutrophus H16 enables the strain to hydrolyze sucrose
No full textFriehs K, Lafferty RM. Cloning and expression of the levanase gene in Alcaligenes eutrophus H16 enables the strain to hydrolyze sucrose. Journal of Biotechnology. 1989;10(3-4):285-291.Genetic engineering methods were used to enhance the substrate spectrum of Alcaligenes eutrophus H16, a poly-[beta]-hydroxybutyric acid (PHB) producer. Using parts of the vector pMMB33 and a 2.5 kb DNA fragment of the Bacillus subtilis chromosome a plasmid was constructed bearing the gene for levanase, an enzyme able to hydrolyze various saccharides. After transfer of the levanase gene by triparental conjugation, the gene, controlled by its own Bacillus subtilis promoter, is expressed in Alcaligenes eutrophus H16 and enables the strain to hydrolyze sucrose. However, growth on sucrose is limited; i.e. the sucrose is not transported efficiently into the cell and/or the levanase is not secreted into the medium
ROTATIONAL LINE STRENGTHS FOR THE 1.27 ELECTRONIC TRANSITION OF
No full textAuthor Institution: Optical Technology Division, National Institute of Standards and TechnologyAccurate line parameters for the near-infrared electronic bands of are important for atmospheric modeling and remote sensing. Here, we report measurements of the rotional linestrengths and pressure-broadening coefficients for the component of the a band of near . The measurements have been measured at resolution and sample pressures from 13kPa to 101kPa using a Fourier-transform infrared spectrometer and a White cell with an optical pathlength of 84 m. The rotational lines follow magnetic-dipole selection rules and have intensities proportional to the sample pressure. The resolved rotational structure overlaps the electric-dipole-allowed collision-induced continuum absorption which is due to binary collisions and which dominates at higher sample pressures. The present measurements will be compared to recent results by other investigators. Efforts are presently underway to determine continuum parameters for the collision-induced background absorption
WIDE-BAND TUNABLE DIODE LASER HETERODYNE MEASUREMENTS
No full text J. P. Sattler, T. L. Worchesky, K. J. Ritter, and W. J. Lafferty, Opt. Lett. 5, 21 (1980)Author Institution:A technique for rapid, accurate, and copious diode laser heterodyne measurements of infrared absorption frequencies will be discussed in By use of a wideband (3 dB width, 1.2 GHz) HgCdTe photomixer and a laser local oscillator, absorptions lying within 9 GHz of a emission line may be measured with care to within 6 MHz. The data from accurate infrared heterodyne measurements of 1,1-difluoroethylene, when supplemented with existing microwave data on the ground state, permit the calculation of submilimeter wave laser emission frequencies to within a few megahertz. Similar measurements on carbonyl sulfide increase its utility as a secondary frequency standard
DIODE LASER STUDY OF THE FUNDAMENTAL OF
No full text W. J. Lafferty, A. G. Maki, and E. K. Plyler, J. Chem. Phys. 40, 224 (1964). A. W. Mantz, P. Connes, G. Guelachvili, and C. Amiot, J. Mol. Spectrosc. 54, 43 (1975).""Author Institution: Scientific Research Staff Ford Motor Company; Department of Physics, The University of MichiganWe have used current-tunable, thin-film PbTe diode lasers to obtain Doppler-limited resolution of the band of in the region 1565-1600 . Roughly 60\% of the interval was covered using different modes of 2 lasers, each mode giving a tuning range of 1-3 cm, Calibration was obtained with HO and NH, while the frequency scale was given by the fringes of a 4-cm Ge etalon, recorded simultaneously using a double beam technique. Near 1600 cm a set of strong regularly spaced lines stands out, which is the R branch of the ground state transition. This band as wel as the ``hot” bands due to the bending vibration indicate a linear structure for the molecule. Preliminary values in cm for the ground state are 1587.392, B^{\prime\prime} - 0.07557, and B - B. This B^{\prime\prime} value differs from that reported by Lafferty et al., but agrees with that by Mantz et al. The next 2 strongest series were interpretable as a band with = 1580.910, B = 0.07606, B - 0.07646, B - B = 4,178 X 10, B - B = 5.259 10. These B values agree with Assignment 2 by Lafferty et al. The assignment of the ground state transition and the shift of the “hot” bands toward lower frequency were substantiated by temperature-difference FTS spectra
LINE INTENSITIES FOR THE 10 BANDS OF
No full textAuthor Institution: Analytical Chemistry Division, CSTL, National Institute of Standards and Technology; Optical technology Division, Physics Laboratory, National Institute of Standards and Technology; Laboratoire de photophysique Moleculaire, CNRS, Universite Paris Sub; Laboratoire de Physique Moleculaire et Applications, CNRS, Universite Paris Sub; Laboratoire de Physique Moleculaire et Applications, Jet Propulsions LaboratoryUsing both high resolution and medium resolution Fourier transform spectra recorded at LPMA Orsay and Kitt Peak, and at NIST Gaithersburg respectively, it has been possible to measure a large set of individual line intensities for the and bands of in the Spectral region. These intensities were introduced in a least squares fit calculation allowing one to get the expansion of the transition moment operator of the and bands of . For these intensities calculations, the theoretical model takes into account the vibration-rotation interactions linking the upper levels involved in the and interacting bands of . Finally a synthetic spectrum of the 10 bands of has been generated, using for the line intensities the dipole moment expansion determined in this work and for the lined positions the parameters and the Hamiltonian matrix given in a previous analysis [J.-M. Flaud, A. Perrin, L.M. Salah, W. J. Lafferty and G. Guelachvili, J. Mol. Spectrose. 160, 272-278 (1993)
Atratividade da vocalização de espécies de anuros para Corethrella spp. (Diptera) no sul do Brasil
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Ecologia, Florianópolis, 2014.A alteração das interações ecológicas representa um aspecto fundamental e comumente negligenciado da modificação antrópica de habitats naturais. Neste estudo investigamos experimentalmente o efeito da alteração da floresta sobre interação parasítica entre mosquitos do gênero Corethrella e anfíbios anuros em uma área de floresta atlântica no Parque Estadual da Serra do Tabuleiro, sul do Brasil. Durante o ano de 2013 realizamos dois experimentos com armadilhas tipo CDC, onde a fonte de luz foi substituída por um aparelho de som com a vocalização de seis espécies de anuros. O primeiro experimento consistiu em distribuir sistematicamente armadilhas em áreas de mata primária e secundária; no segundo, as armadilhas foram dispostas em duas alturas na mata secundária, no chão e a 2m. Capturamos quatro vezes mais coretrelídeos na mata secundária do que na primária, porém a riqueza e a composição foram similares entre os dois habitats. A maior abundância e menor especialização de Corethrella na mata secundária mostra que, para anfíbios, a alteração de seu ambiente natural pode trazer efeitos adversos, como aumento do parasitismo. Não encontramos diferença significativa na abundância, riqueza e composição entre as duas alturas das armadilhas na mata secundária, indicando que o micro-habitat de vocalização do anuro não influencia na interação parasítica. Nossos resultados mostram que áreas secundárias, comparadas com áreas preservadas, mantêm a diversidade e maior abundância de Corethrella, o que pode trazer impactos negativos para a anurofauna que persiste em tais áreas.Abstract : The alteration of ecological interactions is a fundamental and often overlooked aspect of anthropogenic modification of natural habitats. We experimentally investigated the effect of forest disturbance in the parasitic interaction between midges of the genus Corethrella and anuran amphibians in an area of Atlantic Rainforest in the Serra do Tabuleiro State Park, Southern Brazil. During 2013 we conducted two experiments with CDC traps, where the light source was replaced by a stereo with the vocalizations of six species of anurans. In the first experiment, traps were systematically distributed in areas of primary and secondary forest; in the second, the traps were placed in two heights in the secondary forest, at ground level and 2m high. We captured four times more corethrellids in the secondary forest than in the primary, but the richness and species composition were similar between the two habitats. The highest abundance and lower specialization of Corethrella in the secondary forest shows that for anurans, altering their natural environment may have adverse effects, such as increased parasitism. We found no significant difference in the abundance, richness and composition between the two heights of the traps in the secondary forest, indicating that the micro-habitat of the anuran vocalization does not influence the parasitic interaction. Our results show that secondary areas, when compared to primary, maintain the diversity and a greater abundance of Corethrella, which can have negative impacts on the anuran fauna that persists in such areas
Arthur Danto's philosophy of art
No full textThe thesis is a critical examination of Danto's philosophy of art. It begins with his
article 'The Artworld' where he proposes a special is of artistic identification to
distinguish artworks. Danto's idea of the artworld is discussed, a historical and
contextual theory of art, which arose from his attempt to explain the difference
between Warhol's Brillo Boxes sculpture and an indiscernible stack of everyday
Brillo boxes. It is argued that Danto unsuccessfully attempts to shore up his artworld
concept with the special is.
The technique of comparing indiscernible counterparts, from Danto's
book The Transfiguration of the Commonplace, is examined. It is argued that the
technique is philosophically redundant, but it is a redundant premise which has been
added to a valid inference (Danto's historical and contextual view of art: his artworld
theory) therefore, this does not make the original inference invalid.
Danto's treatment of metaphor, expression, and style is shown to result
in four claims. First, artworks embody rhetorical ellipsis. Second, artworks share
features of metaphor: they are intensional (with an s) in structure and cannot be
paraphrased. Third, a work of art expresses what it is a metaphor for by the way it
depicts its subject. Fourth, artworks embody style.
The conclusion, has two parts. The first part gives a summary of the
criticism of Danto's theory of art: (1) there are logical inconsistencies in his concept
of the is of artistic identification and in his use of indiscernible counterparts, (2) his
theory suffers by being over-inclusive and (3) he uses circular arguments. The
second part is based on a response to the criticism: it provides a definition of art.
This has three elements. First, an argument is proposed for a spectrum of artistic
presence in which all human activity and artefacts can be placed. Second, there is an
acceptance of Danto's view of art (or artistic presence) being both intentional (with
a t) and intensional (with an s); however, by applying these concepts to a spectrum,
the problem of over-inclusiveness is avoided. Finally, it is argued there can he no
wholly non-circular account of art
VIRATIONAL, ROTATIONAL, AND TUNNELING DEPENDENCE OF VIBRATIONAL PREDISSOCIATION IN THE HF DIMER
No full text A. S. Pine and W.J. Lafferty, J. Chem. Phys. 28, 2154 (1983). A. S. Pine, W. J. Lafferty. and B. J. Howard, J. Chem. Phys. 81, 2939 (1984). Z. S. Huang. K. W. Jucks and R. E. Miller. J. Chem. Phys. 85, 3338 (1986).Author Institution: Molecular Spectroscopy Division, National Bureau of StandardsAs observed , there is a marked vibrational dependence to the vibrational predissociation rate in the HF dimer with the free-H stretching mode, , much longer lived than the bound-H stretching mode, . Using an optothermal (bolometer-detected) crossed molecular-beam color-center laser spectrometer, we have achieved sufficient resolution to measure the narrow homogeneous linewidths for the band with high precision (). We observe a substantial K, but negligible J. dependence for the predissociation linewidths, and a smaller, but statistically significant, dependence on the tunneling state. For the symmetric lower tunneling level of , the predissociation linewidths are almost twice as broad as the . The widths for the antisymmetric tunneling level are roughly 50\% greater than for the symmetric level for and about for . We also report improved measurements of the broader band predissociation linewidths with reduced spectral congestion and afforded by the low effective temperatures of the adiabatic expansion
HIGH RESOLUTION FT.IR SPECTROSCOPY OF TRANS-1,2-DIFLUOROETHYLENE.D2
No full textS. Saebo and H. Sellers, J. Phys. Chem. 92, 4266 (1988). N. C. Craig, D. W. Brancon and W. J. Lafferty, Forty-Fifth Symposlum on Molecular Spectroscopy, Columbus, OH, MF11. N. C. Craig and J.Overend J. Chem. Phys. 51, 1127 (1969).""Author Institution: Department of Chemistry, Oberlin College; Molecular Physics Division, National Institute of Standards and TechnologyA complete structure of trans-1,2-difluoroethylene, which is a non-polar molecule, would assist in interpreling the surprisingly greater energy of this isomer in comparison with its cis We are in the process of obtaining high resolution () spectra of several bands of three isotopomers of this near-symmetric prolate top molecule with the goal of finding precise ground state rotational constants and a reliable structure. Last year we reported an analysis of three bands in the spectrum of the This year, we report on the preliminary analysis of two bands in the spectrum of the species. From the A-type band at 1176 which is due to antisymme\""oe CF stretching. we obtain initial values of and equal to 0.134021(5) and 0.121108(5) . The higher K levels of this band are slightly perturbed, but a set of upper state constants can be obtained by fitting all observed transitions through K-6. The two ground state constants are in good agreement with values calculated from geometric parameters in which the CCF bond angle and CF bond length were fit to moments of inertia for the species while fixing other parameters to those transferred from the cis isomer. In the trans isomer, the CCF bond angle is smaller, and the CF bond length is longer. In addition the A/B-hybrid band at 1331 has been examined. This band, which is due to the combination tone, is heavily perturbed. The A-type O-branch is split into two strong components separated by 1
VERY HIGH RESOLUTION FOURIER TRANSFORM AND DIODE LASER SPECTRA OF THE BAND OF
No full text. Flicker, R. S. McDowell, N. G. Nereson, and K. Fox, Molecular Spectroscopy Symposium, The Ohio State University, Paper TB5 (1997). A. S. Pine and W. J. Lafferty. Molecular Spectroscopy Symposium, The Ohio State University, Paper ME12 (1978). J. T. Hougen, J. Mol. Spectrosc. 82, 92 (1980).Author Institution:The infrared spectrum of the band of ethane has been recorded with a resolution of using a Fourier transform spectrometer. In addition, twelve Q-branches ranging from have been measured with a diode laser spectrometer capable of Doppler limited resolution (). The line splittings reported by Flicker et , in the Q-branches of this band have been verified and observed in the P- and R-branches as well. Quantum number assignments have been made with the aid of combination differences calculated from well determined ground state Nuclear spin statistics clearly show that the individual transitions are split into their two torsional components even though torsional splitting for this band would be expected to be un-resolvable. The observed splitting is J dependent and varies from K to K. The large splitting observed probably results from an interaction of the state with the components of the v - 3 level of the torsional vibration. Preliminary results will be reported. The most recent theoretical work on this molecule was presented by Hougen and some of the above studies were undertaken as a sequel to the recommendations in his paper
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