823 research outputs found

    Room Temperature Organic Superconductor?

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    The electron--phonon coupling in fullerene C28 has been calculated from first principles. The value of the associated coupling constant lambda/N(0) is found to be a factor three larger than that associated with C60. Assuming similar values of the density of levels at the Fermi surface N(0) and of the Coulomb pseudopotential for C28-based solids as those associated with alkali-doped fullerides A3C60, one obtains Tc(C28) \approx 8 Tc(C60).Comment: 10 pages, 2 figure

    The effect of a new geometric bicycle saddle on the genital-perineal vascular perfusion of female cyclists

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    Purpose. — Female cyclists undergo a perineal compression of the pudendal nerve and genitalperineal area, with underexplored effects on genital injuries and sexual dysfunctions. This study tests the effects of a new geometric bicycle saddle (SMP) on perineal compression, blood perfusion, genital sensation and sexual function. Methods. — Thirty-three professional female athletes were monitored when using both the new saddle and a traditional professional saddle, in a randomized order. Short-term effects are estimated by measuring the partial pressure of vagina transcutaneous oxygen (PtcO2) before using the saddle, after 10 minutes of static sitting, after riding 20 minutes. Long-term effects are estimated by measuring athletes Female Sexual Distress Scale (FSDS) before using the new saddle and after 6 months using it. Results. — From an initial average of 70 mmHg, PtcO2 decreases by 30 mmHg after riding on a traditional saddle, 10 mmHg on the new saddle (respectively 20 and 7 after just sitting). When using the traditional saddle all FSDS scores are well over the 12 ‘‘normality’’ threshold, with an average of 41, while after using the new saddle the average falls to 12. All differences between the saddles are strongly significant: paired t-tests > 6; P < 0.001; 95% confidence intervals respectively 13 ± 3 mmHg after sitting, 20 ± 3 mmHg after riding, 29 ± 2 FSDS scores. Conclusion. — Traditional saddles have strong negative effects on the vascular perfusion of the vulva, with possible consequences on female sexual functions. The SMP saddle reduces the compression on the pelvic floor and can help reducing the incidence of urogenital pathologies for female cyclists

    Packing of R3 by crosses

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    The existence of tilings of R^n by crosses, a cluster of unit cubes comprising a central one and 2n arms, has been studied by several authors. We have completely solved the problem for R^2, characterizing the crosses which lattice tile R^2, as well as determining the maximum packing density for the crosses which do not lattice tile the plane. In this paper we motivate a similar approach to study lattice packings of R^3 by crosses.The existence of tilings of Rn by crosses, a cluster of unit cubes comprising a central one and 2n arms, has been studied by several authors. We have completely solved the problem for R2 characterizing the crosses which lattice tile R2 as well as determining the maximum packing density for the crosses which do not lattice tile the plane. In this paper we motivate a similar approach to study lattice packings of R3 by crosses.publishe

    Effect of Torulaspora delbrueckii Yeast on the Anthocyanin and Flavanol Concentrations of Cabernet franc and Pinotage Wines

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    Pinotage and Cabernet franc grape must were inoculated with Saccharomyces cerevisiae and Torulasporadelbrueckii yeasts. Differences in colour were observed between Pinotage (S. cerevisiae) and Pinotage (T.delbrueckii) wines, whereas differences in berry and herbaceous character were observed between Cabernetfranc (S. cerevisiae) and Cabernet franc (T. delbrueckii) wines. Mouthfeel properties between treatmentsfor both wines were not significantly different. Overall quality was slightly higher in wines inoculatedwith T. delbrueckii compared to wines inoculated with S. cerevisiae. Anthocyanins and flavanols measuredin Pinotage wines made with T. delbrueckii were higher compared to Pinotage must inoculated with S.cerevisiae. Cabernet franc wines made with S. cerevisiae were higher in anthocyanin glycoside and flavanolconcentrations compared to Cabernet franc wines made with T. delbrueckii. Insignificant differencesin acetylated and coumarylated anthocyanins were evident between Cabernet franc (S. cerevisiae) andCabernet franc (T. delbrueckii) wines. Principal component analysis showed that epigallocatechin gallate,epicatechin gallate, procyanidin B2, peonidin 3-O-glucoside, delphinidin 3-(6-acetyl) glucoside, petunidin3-(6-acetyl) glucoside, malvidin 3-(6-acetyl) glucoside and malvidin 3-O-glucoside concentrationswere highest in Pinotage wines inoculated with T. delbrueckii. Cabernet franc wines inoculated with S.cerevisiae yeasts were highest in malvidin 3-(6-p-coumaroyl) glucoside, petunidin 3-(6-p-coumaroyl)glucoside, petunidin 3-O-glucoside, epicatechin gallate and epigallocatechin gallate concentrations. Totalanthocyanins were highest in Pinotage (S. cerevisiae) wines and Cabernet franc (T. delbrueckii) wines.Flavanols were highest in Pinotage (T. delbrueckii) and Cabernet franc (S. cerevisiae) wines. It is evidentfrom the results that yeast species has an impact on the flavonoid concentrations within a grape variety

    Restriction conditions on PL(7, 2) codes (3 ≤ |_i| ≤ 7)

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    The Golomb-Welch conjecture states that there is no perfect r-error correcting Lee code of word length n over ℤ for n ≥ 3 and r ≥ 2. This problem has received great attention due to its importance in applications in several areas beyond mathematics and computer sciences. Many results on this subject have been achieved, however the conjecture is only solved for some particular values of n and r, namely: 3 ≤ n ≤ 5 and r ≥ 2; n = 6 and r = 2. Here we give an important contribution for the case n = 7 and r = 2, establishing cardinality restrictions on codeword sets

    Electron-Phonon Coupling in Charged Buckminsterfullerene

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    A simple, yet accurate solution of the electron-phonon coupling problem in C_{60} is presented. The basic idea behind it is to be found in the parametrization of the ground state electronic density of the system calculated making use of ab-initio methods, in term of sp2+x^{2+x} hybridized orbitals. This parametrization allows for an economic determination of the deformation potential associated with the fullerene's normal modes. The resulting electron-phonon coupling constants are used to calculate Jahn-Teller effects in C_{60}^-, and multiple satellite peaks in the corresponding photoemission reaction. Theory provides an accurate account of the experimental findings.Comment: 11 pages, 3 figures. Accepted for publication in Chem. Phys. Let

    A Narrative Review about Prosocial and Antisocial Behavior in Childhood: The Relationship with Shame and Moral Development

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    We conducted a literature review aimed at identifying the origins of shame as well as its effects on moral development, especially in terms of behavioral outcomes, and we reflected on the practical implications of our findings. We explored the role of shame in moral development through cultural differences and parental influences, collecting evidence of psychopathological consequences of primary moral emotion dysregulation. These studies showed a dichotomous feature of shame, as a prosocial behavior enhancer in morally relevant situations and, simultaneously, a risk factor for aggressive and antisocial behaviors on other occasions. Dysregulated shame leads to maladaptive interpersonal behaviors, which could evolve towards psychopathological paths. Therefore, an integrated intervention is recommended in children with emotional/behavioral problems

    Cultivares e sistemas de cultivo de cebola no verão.

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    O presente trabalho foi realizado em São José do Rio Pardo. com o objetivo de avaliar o comportamento de cultivares de cebola Alfa Tropical, Alfa São Francisco e Mercedes em quatro sistemas de cultivo no verão. O experimento foi conduzido no delineamento de blocos casualizados, com quatro repetições e arranjo em parcelas subdivididas. Muda's de cebola produzidas em canteiros ou em bandejas de 200 células foram transplantadas em sistema convencional e direto na palha. A interação entre sistemas de cultivo e ,cultivares foi significativa na produtividade e incidência do mal-das-sete-voltas. A produtividade total variou entre 0.7 e 55.1 t ha-1. sendo as mais baixas produtividades obtidas com a cultivar Mercedes em todos os sistemas de cultivo. Foi observado que a produtividade e a precocidade de colheita foram maiores ou a incidência do mal-das-sete-voltas menor com as mudas de bandejas/ Em geral, a produtividade ou a precocidade de colheita tenderam a aumentar com a redução do preparo do solo. O transplantio direto na palha de mudas de bandejas é uma opção viável para a produção de cebola com sustentabilidade ambiental no verão.Suplemento. Edição dos resumos expandidos do 46. Congresso Brasileiro de Olericultura, Goiânia, ago. 2006

    Electron-phonon interaction in C70

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    The matrix elements of the deformation potential of C70_{70} are calculated by means of a simple, yet accurate solution of the electron-phonon coupling problem in fullerenes, based on a parametrization of the ground state electronic density of the system in terms of sp2+xsp^{2+x} hybridized orbitals. The value of the calculated dimensionless total electron-phonon coupling constant is λ≈0.1\lambda\approx0.1, an order of magnitude smaller than in C60_{60}, consistent with the lack of a superconducting phase transition in C70_{70}A3_3 fullerite, and in overall agreement with measurements of the broadening of Raman peaks in C70_{70}K4_4. We also calculate the photoemission cross section of C70−_{70}^-, which is found to display less structure than that associated with C60−_{60}^-, in overall agreement with the experimental findings.Comment: To be published in Phys. Rev.
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