1,132 research outputs found

    Burning Man Values Examined: Gratitude as a Culturally-Driven and Value-Based Organizational Mainstay

    Get PDF
    Gratitude expression is examined as a culturally-derived principle that can be adopted as a best practices strategy that can make organizations more dynamic and human relationships more meaningful. Burning Man is presented as an exemplar of gratitude implementation by crafting the expression of gratitude into an elevated organizational phenomenon (including a cultural principal of unconditional gifting). Burning Man has also crafted a “Culture of Appreciation” as a set of organizationally-derived practices complementary to processes of gratitude implementation. The paper concludes with a discussion of gratitude and appreciation as an organizational mainstay

    The UV absorption spectrum of C60 (buckminsterfullerene): A narrow band at 3860 Å

    Get PDF
    The absorption spectrum of the special C60 cluster buckminsterfullerene has been studied in a supersonic beam by laser depletion of the cold van der Waals complexes of C60 with benzene and methylene chloride. Both complexes were found to display a single, isolated absorption band in the near ultraviolet superimposed on a structureless absorption continuum. For the methylene chloride complex this feature is centered at 3860 Å, and is roughly 50 cm−1 wide. In the benzene van der Waals cluster, the corresponding feature is located at 3863 Å, and has a similar width. This spectrum is tentatively assigned to the 0–0 band of the lowest 1T1u<--1Ag (LUMO+1<--HOMO) transition of a truncated icosahedral carbon shell structure, broadened by coupling to the underlying quasicontinuum of ground state vibrational levels

    The Electronic Spectrum of Fullerenes from the Dirac Equation

    Full text link
    The electronic spectrum of sheets of graphite (plane honeycomb lattice) folded into regular polihedra is studied. A continuum limit valid for sufficiently large molecules and based on a tight binding approximation is derived. It is found that a Dirac equation describes the flat graphite lattice. Curving the lattice by insertion of odd numbered rings can be mimicked by coupling effective gauge fields. In particular the C60C_{60} and related molecules are well described by the Dirac equation on the surface of a sphere coupled to a color monopole sitting at its center.Comment: 29 pages, 7 figures. IASSNS-HEP-92/5

    Soil organisms in organic and conventional cropping systems.

    Get PDF
    Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponíveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivíduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior índice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamília Oribatuloidea. Indivíduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas

    Magic Numbers of Silicon Clusters

    Full text link
    A structural model for intermediate sized silicon clusters is proposed that is able to generate unique structures without any dangling bonds. This structural model consists of bulk-like core of five atoms surrounded by fullerene-like surface. Reconstruction of the ideal fullerene geometry results in the formation of crown atoms surrounded by π\pi-bonded dimer pairs. This model yields unique structures for \Si{33}, \Si{39}, and \Si{45} clusters without any dangling bonds and hence explains why these clusters are least reactive towards chemisorption of ammonia, methanol, ethylene, and water. This model is also consistent with the experimental finding that silicon clusters undergo a transition from prolate to spherical shapes at \Si{27}. Finally, reagent specific chemisorption reactivities observed experimentally is explained based on the electronic structures of the reagents.Comment: 4 pages + 3 figures (postscript files after \end{document}

    Theta Wave Coherence in Pre-Semantic Processing: An EEG study of Autism Spectrum Disorder

    Get PDF
    Language deficits are a pertinent and characteristic feature of Autism Spectrum Disorder (ASD), particularly in higher-level functions like semantic processing. Compared to the typically developing (TD) population, people with ASD have shown significant differences in neural semantic processing activity after the presentation of a stimulus. However, lower-level functions like word decoding are typically intact, suggesting a disconnect between these two processing levels in the brain. Theta coherence has been linked to the presence of such lower-level, pre-semantic activity in the TD population. The present study used electroencephalography (EEG) to measure the presence of theta coherence and examine the pre-semantic neural connectivity of participants with ASD to determine whether early disruptions might contribute to semantic misunderstandings. Gaining a better understanding of neural communication during pre-semantic processing would further the current understanding of language impairments in ASD and could also lead to more targeted and effective therapies

    Enrichment of CH3F nuclear spin isomers by resonant microwave radiation

    Get PDF
    Theoretical model of the coherent control of nuclear spin isomers by microwave radiation has been developed. Model accounts the M-degeneracy of molecular states and molecular center-of-mass motion. The model has been applied to the 13CH3F molecules. Microwave radiation excites the para state (J=11,K=1) which is mixed by the nuclear spin-spin interaction with the ortho state (9,3). Dependencies of the isomer enrichment and conversion rates on the radiation frequency have been calculated. Both spectra consist of two resonances situated at the centers of allowed and forbidden (by nuclear spin) transitions in the molecule. Larger enrichment, up to 7%, can be produced by strong radiation resonant to the forbidden transition. The spin conversion rate can be increased by 2 orders of magnitude at this resonance.Comment: REVTEX, 14 pages + 6 eps figure

    Coherent control of enrichment and conversion of molecular spin isomers

    Get PDF
    A theoretical model of nuclear spin conversion in molecules controlled by an external electromagnetic radiation resonant to rotational transition has been developed. It has been shown that one can produce an enrichment of spin isomers and influence their conversion rates in two ways, through coherences and through level population change induced by radiation. Influence of conversion is ranged from significant speed up to almost complete inhibition of the process by proper choice of frequency and intensity of the external field.Comment: REVTEX, 13 pages + 6 eps figure

    Theory of nuclear spin conversion in ethylene

    Get PDF
    First theoretical analysis of the nuclear spin conversion in ethylene molecules (13^CCH4) has been performed. The conversion rate was found equal approx. 3x10^{-4} 1/s*Torr, which is in qualitative agreement with the recently obtained experimental value. It was shown that the ortho-para mixing in 13^CCH4 is dominated by the spin-rotation coupling. Mixing of only two pairs of ortho-para levels were found to contribute significantly to the spin conversion.Comment: 20 pages, 5 eps figure

    Small-Size Resonant Photoacoustic Cell of Inclined Geometry for Gas Detection

    Full text link
    A photoacoustic cell intended for laser detection of trace gases is represented. The cell is adapted so as to enhance the gas-detection performance and, simultaneously, to reduce the cell size. The cell design provides an efficient cancellation of the window background (a parasite response due to absorption of laser beam in the cell windows) and acoustic isolation from the environment for an acoustic resonance of the cell. The useful photoacoustic response from a detected gas, window background and noise are analyzed in demonstration experiments as functions of the modulation frequency for a prototype cell with the internal volume ~ 0.5 cm^3. The minimal detectable absorption for the prototype is estimated to be ~ 1.2 10^{-8} cm^{-1} W Hz^{-1/2}.Comment: 11 pages, 5 figure
    corecore