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Cooke S.A.,Purchase College SUNY | Minei A.J.,College of Mount Saint Vincent
Journal of Molecular Spectroscopy | Year: 2013

Broadband rotational free induction decays (FIDs) from 1H,2H- perfluorocyclobutane have been captured at a rate of 25 ps/point for a duration of 20 μs. FIDs have been treated using fast Fourier transformation (FFT) and singular value decomposition (SVD). It is demonstrated that the SVD-based model can yield a sufficient number of accurate transition frequencies for initial spectral analysis using only ≈1% (200 ns) of the FID. Furthermore, the SVD-based analysis has produced information concerning transition phase, amplitude, damping, and frequency for the strongest molecular signals. The damping factors determined appear useful in distinguishing molecular and non-molecular signals. The FFT analysis of the full FID has yielded, for the first time, spectroscopic parameters for the parent and all C-13 isotopologues of both the cis and trans species. © 2012 Elsevier Inc. All rights reserved.

Yorke S.R.,University of Wisconsin - Milwaukee | Schnitzer S.A.,University of Wisconsin - Milwaukee | Schnitzer S.A.,Smithsonian Tropical Research Institute | Mascaro J.,University of Wisconsin - Milwaukee | And 4 more authors.
Biotropica | Year: 2013

Recent evidence suggests that liana abundance and biomass are increasing in Neotropical forests, representing a major structural change to tropical ecosystems. Explanations for these increases, however, remain largely untested. Over an 8-yr period (1999-2007), we censused lianas in nine, 24 × 36 m permanent plots in old-growth and selectively logged forest at La Selva Biological Station, Costa Rica to test whether: (1) liana abundance and basal area are increasing in this forest; (2) the increase is being driven by increased recruitment, decreased mortality, or both; and (3) long-distance clonal colonization explains the increase in liana abundance and basal area. We defined long-distance clonal colonization as lianas that entered and rooted in the plots as vegetative propagules of stems that originated from outside or above the plot, and were present in 2007, but not in 1999 or 2002. Our hypotheses were supported in the old-growth forest: mean liana abundance and BA (≥1 cm diameter) increased 15 and 20 percent, respectively, and clonal colonization from outside of the plots contributed 19 and 60 percent (respectively) to these increases. Lianas colonized clonally by falling vertically from the forest canopy above or growing horizontally along the forest floor and re-rooting-common forms of colonization for many liana species. In the selectively logged forest, liana abundance and BA did not change, and thus the pattern of increasing lianas may be restricted to old-growth forests. In summary, our data support the hypothesis that lianas are increasing in old-growth forests, and that long-distance clonal colonization is a major contributor. © 2013 The Author(s) Journal compilation © 2013 by The Association for Tropical Biology and Conservation.

Grubbs II G.S.,Wesleyan University | Groner P.,University of Missouri - Kansas City | Novick S.E.,Wesleyan University | Cooke S.A.,Purchase College SUNY
Journal of Molecular Spectroscopy | Year: 2012

The effects of partial fluorination on acetone have been examined using broadband rotational spectroscopy within the 7.5-16.5 GHz region. The broadband spectrum, which contains information on the methyl group internal rotation, was analyzed using a principal axis method, and subsequently analyzed using (i) a combined axis method and (ii) a method in which the Hamiltonian possesses matrix elements expressed as Fourier series. Spectroscopic constants and effective barriers to methyl group internal rotation are presented for the first time. Results are compared to related molecules where it is shown that the carbonyl group effectively limits the effects of fluorination on the adjacent C(O)CH 3 structure. The spectroscopic analyses performed demonstrate a satisfactory convergence of the Hamiltonian in all combinations of Watson reduction and representation with the exception of A and I r. Within this combination the ratio (2A - B - C)/(B - C) is large resulting in unreasonably large values of the quartic centrifugal distortion constant δ K which in turn prohibits a satisfactory eigenvalue solution. © 2012 Elsevier Inc. All rights reserved.

Siegel P.,Purchase College SUNY
Emotion (Washington, D.C.) | Year: 2012

This study compared the effects of exposure to masked and unmasked phobic stimuli on phobic behavior. Participants were identified as spider-phobic with a questionnaire and a Behavioral Avoidance Test (BAT) with a live tarantula (N = 101). One week later, they were administered one of three types of exposure: very brief (25 ms) or clearly visible (120 ms) images of spiders, or very brief images of flowers. They reported ratings of subjective distress just before and after these exposures, and engaged in the BAT again thereafter. Two weeks later, 57 participants returned for a follow-up BAT. The results indicated a double dissociation between the effects of very brief and clearly visible exposure: the former reduced avoidance of the tarantula and did not affect distress, whereas the latter increased distress but did not affect avoidance. The behavioral effect lasted for two weeks. These findings suggest that avoidance of a feared object can be reduced without full conscious awareness. The theoretical implications are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Bailey W.C.,Kean University | Powoski R.A.,University of North Texas | Powoski R.A.,Glori Energy | Cooke S.A.,Purchase College SUNY
Journal of Molecular Spectroscopy | Year: 2012

Quantum chemical calculations have been performed on the potential energy surfaces of the two title molecules. The calculations have located the two lowest energy conformations for each molecule. For all four structures, centrifugal distortion constants and chlorine nuclear quadrupole coupling tensor components have been calculated. Analyses of the experimental rotational spectra have yielded the identification of only one conformer for each molecule. These conformers have spectroscopic constants closely matching those of the calculated lowest energy conformers. The chlorine nuclear quadrupole coupling tensor components of the title molecules have been compared with those for propionyl chloride and perfluoropropionyl chloride. © 2012 Elsevier B.V. All rights reserved.

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