899 research outputs found
The effect of ambient scent on moviegoers’ behavior
Atmospheres influence behavior, create a positive image, and influence consumer purchasing patterns and retail perceptions. Nonetheless, the physical environment is a potential source of competitive advantage, though neglected more often than not. In particular, research on the effects of aroma as an independent variable in natural settings is very limited and requires further research. A sample of 407 moviegoers participated in a “natural experiment” in a cinema complex, using scented and unscented conditions. Findings show that scent produces significant positive differences in the evaluation of the theater, its environment, and on intention to return. No significant differences are found in the evaluations of concession products sold, despite the fact that spectators in scented rooms considered product prices to be significantly cheaper than did spectators in unscented rooms. A major implication of this study is that scent significantly affects emotional reactions to atmospheres. Retailers can thus improve environments to create enjoyable experiences and positively influence consumer responses
Polarons in Carbon Nanotubes
We use ab initio total-energy calculations to predict the existence of
polarons in semiconducting carbon nanotubes (CNTs). We find that the CNTs' band
edge energies vary linearly and the elastic energy increases quadratically with
both radial and with axial distortions, leading to the spontaneous formation of
polarons. Using a continuum model parametrized by the ab initio calculations,
we estimate electron and hole polaron lengths, energies and effective masses
and analyze their complex dependence on CNT geometry. Implications of polaron
effects on recently observed electro- and opto-mechanical behavior of CNTs are
discussed.Comment: Revtex preprint format, 12 pages, 2 eps figures, source in LaTeX.
Accepted for publication in Physical Review Letter
Preparation of the conducting nanocomposites using molded inorganic matrix: fibrous cerium(IV) hydrogenphosphate as a self-supported pyrrole polymerization agent
New supported polypyrrole nanocomposites have been prepared and studied in this work. Self-supported sheets of fibrous cerium(IV) hydrogenphosphate (CePf) were used as the inorganic matrix, since the fibrous morphology presented by this material makes molding possible, giving a desired shape to the final polypyrrole/ CePf conducting nanocomposites. The influence of pyrrole concentration on the nanocomposite preparation was studied, as well as the influence of CePf on the polypyrrole characteristics. XRD, Raman, SEM and conductivity measurement data show the conducting polypyrrole coating CePf fibers, yielding self-supported sheets of organic-inorganic conducting nanocomposites.1361378138
First-principles modeling of the thermoelectric properties of SrTiO/SrRuO superlattices
Using a combination of first-principles simulations, based on the density
functional theory and Boltzmann's semiclassical theory, we have calculated the
transport and thermoelectric properties of the half-metallic two dimensional
electron gas confined in single SrRuO layers of SrTiO/SrRuO
periodic superlattices. Close to the Fermi energy we find that the
semiconducting majority spin channel displays a very large in-plane component
of the Seebeck tensor at room temperature, = 1500 V/K, and the
minority spin channel shows good in-plane conductivity = 2.5
(mcm). However, contrary to the expectation of Hicks and
Dresselhaus model about enhanced global thermoelectric properties due to the
confinement of the metallic electrons, we find that the total power factor and
thermoelectric figure of merit for reduced doping is too small for practical
applications. The reason for this failure can be traced back on the electronic
structure of the interfacial gas, which departs from the free electron
behaviour on which the model was based. The evolution of the electronic
structure, electrical conductivity, Seebeck coefficient, and power factor as a
function of the chemical potential is explained by a simplified tight-binding
model. We find that the electron gas in our system is composed by a pair of one
dimensional electron gases orthogonal to each other. This reflects the fact the
physical dimensionality of the electronic system can be even smaller than that
of the spacial confinement of the carriers.Comment: 9 pages, 7 figure
Highly-confined spin-polarized two-dimensional electron gas in SrTiO/SrRuO superlattices
We report first principles characterization of the structural and electronic
properties of (SrTiO)/(SrRuO) superlattices. We show
that the system exhibits a spin-polarized two-dimensional electron gas,
extremely confined to the 4 orbitals of Ru in the SrRuO layer. Every
interface in the superlattice behaves as a minority-spin half-metal
ferromagnet, with a magnetic moment of = 2.0 /SrRuO
unit. The shape of the electronic density of states, half metallicity and
magnetism are explained in terms of a simplified tight-binding model,
considering only the orbitals plus (i) the bi-dimensionality of the
system, and (ii) strong electron correlations.Comment: 5 pages, 4 figure
Contact-induced spin polarization in carbon nanotubes
Motivated by the possibility of combining spintronics with molecular
structures, we investigate the conditions for the appearance of
spin-polarization in low-dimensional tubular systems by contacting them to a
magnetic substrate. We derive a set of general expressions describing the
charge transfer between the tube and the substrate and the relative energy
costs. The mean-field solution of the general expressions provides an
insightful formula for the induced spin-polarization. Using a tight-binding
model for the electronic structure we are able to estimate the magnitude and
the stability of the induced moment. This indicates that a significant magnetic
moment in carbon nanotubes can be observed.Comment: To appear in Phys. Rev. B (2003
Perceptions of Portuguese parents about the acceptability of a multicomponent intervention targeted at behavioral inhibition during early childhood
High and stable behavioral inhibition during early childhood is a risk factor for later anxiety disorders. The few available interventions targeted at behavioral inhibition have not yet been implemented in European countries. Evaluating intervention acceptability is essential when introducing interventions in new cultures. This study aimed to explore the perceptions of parents about the acceptability of the multicomponent Turtle Program in Portugal. Participants were 12 parents (from seven families) of children with a positive screening on the Behavioral Inhibition Questionnaire and no diagnoses of developmental disorders/selective mutism. Children's mean age was 55.86 months and most children were female and first-born. Parents and children participated in the eight-sessions Turtle Program. After each session, parents completed weekly satisfaction checklists. Following completion of the full intervention, parents were invited to participate in individual qualitative in-depth interviews. The thematic analysis revealed that both parents perceived the intervention objectives and contents as relevant. Both parents suggested the introduction of follow-up sessions, the discussion of practical experiences, the need to be sensitive to cultural differences in positive language, and the provision of more feedback about children's activities. These findings support prior research on the acceptability and cultural tailoring needed for parenting and child socioemotional learning interventions.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Paracoccidioidiomycosis: case report
Os autores reportam o caso clínico de um homem, 43 anos de idade, natural e residente na ilha da Madeira, emigrado na Venezuela até há 6 anos. Em Março 2009, observado por aparecimento de lesão pápulo-crostosa de bordos regulares eritematosos, indolor, pruriginosa, com dimensões de 4,5 x 3
cm, localizada no dorso, com 2 meses de evolução. Como antecedentes, refere história de lesão da mucosa bucal, com exame histopatológico compatível com paracoccidioidomicose (PCM). Foram efectuadas duas biópsias da lesão cutânea para avaliação histopatológica e micológica. O exame histopatológico revelou a presença de múltiplas células circulares, sugerindo distribuição característica de “roda de leme”. O estudo micológicos revelou, no exame directo, a presença de leveduras – algumas em gemulação. As culturas permitiram isolar o Paracoccidioides brasiliensis. A radiografia pulmonar apresentava infiltrado bilateral e simétrico, nos lobos centrais e basais. A Tomografia Axial Computadorizada torácica demonstrou múltiplos nódulos espiculados, áreas de opacidade e bronquiectasias. Foi efectuada broncofibroscopia (sem alterações) e simultaneamente foi obtido o lavado broncoalveolar (LBA). A cultura, a 25º C, revelou a presença de hifas e clamidósporos (forma filamentosa). Na cultura, a 37º C, não se obteve a forma leveduriforme. O tratamento efectuado foi o itraconazol 200 mg/dia, durante 6 meses, com regressão da lesão. Até à actualidade, nenhum caso de PCM foi reportado na ilha da Madeira, Portugal. Embora não seja frequente, fora das áreas endémicas, os dermatologistas devem ser capazes de reconhecer e diagnosticar micoses sistémicas, como a PCM.We report a case of a 43 years-old portuguese man, natural and resident in Madeira island, who was emigrated in Venezuela until 6 years ago. He was observed on March 2008 for a crusted papulo-nodular lesion with erythematous regular borders, pruritic and sized 4,5 x 3,0 cm, located on the dorsum, with a 2 month history. There was no palpable lymphadenopathy. He denied other simptomatology. On March of 1999, the patient had a mouth lesion which was compatible with paracoccidioidomycosis on histopathological examination. He was not aware of any associated pathologies. We
performed two punch biopsies of the cutaneous lesion for histopathological and mycological examination. The histopathology showed the presence of multiple round cells of different size (yeast cells) in a narrow base suggesting the classic “pilot’s wheels”, on Hematoxiline & Eosine stain. On direct microscopic examination the mycology revealed yeast of different sizes – some of them on gemulation. The
cultures, at 24º and 37º, isolated Paracoccidioides brasiliensis. The thoracic x-ray revealed a heterogeneous, bilateral and symmetric pattern located towards the central and basal portions. The CT scan of the chest showed multiple, micronodular and striated lesions (some of them with small cavities), with tendency to coalesce. To characterize better these lung abnormalities, the patient performed a fibrobronchoscopy of the respiratory tract which was normal. The culture, at 25 ºC, obtained from the sputum of the bronchoalveolar lavage fluid (BAL) showed Paracoccidioides brasiliensis.
Routine laboratory studies were normal and serology negative for HIV and tuberculosis. The treatment of choice was itraconazol 200 mg/day, for 6 months. As far as we know no case of PCM has been reported in Madeira. Although it is not a frequent disease outside the endemic areas, dermatologists should be able to recognise and diagnose systemic mycosis like PCM.info:eu-repo/semantics/publishedVersio
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