Chaotic dynamics in billiards using Bohm’s quantum mechanics

The dynamics of a particle in square and circular billiards is studied within the framework of Bohm’s quantum mechanics. While conventional quantum mechanics predicts that the system shows no indication of chaotic behavior for these geometries from either the eigenvalue spectra distribution or the structure of the eigenfunctions, we find that in Bohm’s quantum mechanics these systems exhibit both regular and chaotic behavior, depending on the form of the initial wave packet and on the particle’s initial position

Comment on “Inelastic Collapse of a Randomly Forced Particle” by Cornell et al.

A Comment on the Letter by Stephen J. Cornell, Michael R. Swift, and Alan J. Bray, Phys. Rev. Lett. 81, 1142 (1998). The authors of the Letter offer a Reply

Quantum chaos in a double square-well: An approach based on Bohm\u27s view of quantum mechanics

We study the dynamics of a quantum particle in a double square-well potential within a deterministic framework using Bohm’s quantum mechanics. Phase portraits, Fourier spectral analysis, Poincaré sections, and Lyapunov exponents clearly indicate that the particle undergoes periodic, quasiperiodic, and chaotic motions depending on the initial form of the wave packet. We also make a detailed comparison between the predictions of the present approach and those of conventional quantum mechanics for the same problem

Correlation equalities and upper bounds for the transverse Ising model

Starting from an exact formal identity for the two-state transverse Ising model and using correlation inequalities rigorous upper bounds for the critical temperature and the critical transverse field are obtained which improve effective results.Comment: 8 pages, 1 figur

Phenolic compound profile by UPLC-MS/MS and encapsulation with chitosan of Spondias mombin L. fruit peel extract from Cerrado hotspot-Brazil

8openInternationalInternational coauthor/editorTaperebá (Spondias mombin L.) is a native species of the Brazilian Cerrado that has shown important characteristics such as a significant phenolic compound content and biological activities. The present study aimed to characterize the phenolic compound profile and antioxidant activity in taperebá peel extract, as well as microencapsulating the extract with chitosan and evaluating the stability of the microparticles. The evaluation of the profile of phenolic compounds was carried out by UPLC-MS/MS. The in vitro antioxidant activity was evaluated by DPPH and ABTS methods. The microparticles were obtained by spray drying and were submitted to a stability study under different temperatures. In general, the results showed a significant content of polyphenols and antioxidant activity. The results of UPLC-MS/MS demonstrated a significant content of polyphenols in taperebá peel, highlighting the high content of ellagic acid and quercetin compounds. There was significant retention of phenolic compounds when microencapsulated, demonstrating high retention at all evaluated temperatures. This study is the first to microencapsulate the extract of taperebá peel, in addition to identifying and quantifying some compounds in this fruitopenBrito, Giovanna Oliveira de; Reis, Bruna Cabral; Ferreira, Eduardo A; Vilela Junqueira, Nilton T; Sá-Barreto, Lívia C L; Mattivi, Fulvio; Vrhovsek, Urska; Gris, Eliana FortesBrito, G.O.D.; Reis, B.C.; Ferreira, E.A.; Vilela Junqueira, N.T.; Sá-Barreto, L.C.L.; Mattivi, F.; Vrhovsek, U.; Gris, E.F

Descrição do Girino de Aplastodiscus Arildae (Cruz & Peixoto, 1985) (Amphibia, Anura, Hylidae)

The tadpole of Aplastodiscus arildae, from Estação Ecológica de Fechos, Municipality of Nova Lima, State of Minas Gerais, is described and figured. Tadpoles from Parque das Mangabeiras, Municipality of Belo Horizonte, were also examined. Tadpoles were found on the bottom of rocky hillside streams backwaters, edged by riparian vegetation. Tadpoles of A. arildae present labial tooth row formula 2(2)/4(1), oral disc with a median small gap in the anterior labium papillae row, few submarginal papillae without horned teeth, dark red iris and body with marbled olive-brown color in life. These characteristics distinguish A. arildae tadpoles from the tadpoles of A. albofrenatus and A. eugenioi, the already described tadpoles for the A. albofrenatus species group.É descrito e figurado o girino de Aplastodiscus arildae, proveniente da Estação Ecológica de Fechos, Município de Nova Lima, região centro-sul do Estado de Minas Gerais. Girinos coletados no Parque das Mangabeiras, Município de Belo Horizonte, Minas Gerais, foram também examinados. Os girinos foram encontrados sobre o leito de remansos em riachos encachoeirados, permanentes e margeados por vegetação ripária. Apresentam fórmula dentária 2(2)/4(1), disco oral com uma pequena interrupção mediana na fileira de papilas do lábio anterior, poucas papilas submarginais laterais sem dentículos córneos, íris vermelho escuro e corpo com coloração marmoreada pardo-olivácea em vida. Essas características distinguem o girino de A. arildae dos girinos de A. albofrenatus e A. eugenioi, os únicos conhecidos para o grupo de espécies de A. albofrenatus

Resolvent estimates for normally hyperbolic trapped sets

We give pole free strips and estimates for resolvents of semiclassical operators which, on the level of the classical flow, have normally hyperbolic smooth trapped sets of codimension two in phase space. Such trapped sets are structurally stable and our motivation comes partly from considering the wave equation for Kerr black holes and their perturbations, whose trapped sets have precisely this structure. We give applications including local smoothing effects with epsilon derivative loss for the Schr\"odinger propagator as well as local energy decay results for the wave equation.Comment: Further changes to erratum correcting small problems with Section 3.5 and Lemma 4.1; this now also corrects hypotheses, explicitly requiring trapped set to be symplectic. Erratum follows references in this versio

Identification and diagnosis of salt-affected soils in the Baixo-Açu irrigated perimeter, RN, Brazil.

Soil salinization is one of the main environmental problems in arid and semi-arid regions. Thus, the objective of this study was to evaluate the problems of soil salinity in an area of the Baixo-Açu Irrigated Perimeter, RN, Brazil, through joint analysis using remote sensing, pedology and geostatistics techniques. The study was conducted in the Baixo-Açu Irrigated Perimeter (1500 ha), with soil salinity sampling at 42 points, used to correlate with the Salinity Index 1 (SI1) spectral index. After spectral analysis, one of the lots identified with salinity problems was selected and subjected to pedological analysis to classify the problems of soil salinity in surface and in subsurface. Subsequently, 45 points were sampled in the same lot to assess the spatial distribution of soil salinity and diagnosis of the problem of salinity using geostatistical analysis. The SI1 index in areas with Normalized Difference Vegetation Index (NDVI) < 0.33 showed the highest correlation with soil electrical conductivity. The soil in the evaluated area showed saline horizon in surface and saline-sodic horizon in subsurface. The areas most affected by salinity are concave areas, with deficiency of natural drainage. A salinização do solo é um dos principais problemas ambientais em regiões áridas e semiáridas. Deste modo, objetivou-se avaliar os problemas de salinidade do solo em uma área do Perímetro Irrigado do Baixo-Açu, RN, Brasil, por meio de análise conjunta empregando técnicas de sensoriamento remoto, pedologia e geoestatística. O estudo foi desenvolvido no Perímetro Irrigado do Baixo-Açu (1500 ha), com amostragem da salinidade do solo em 42 pontos amostrais, utilizados para correlacionar com o índice espectral 'Salinity Index 1' (SI1). Após a análise espectral selecionou-se um dos lotes identificados com problemas de salinidade, no qual foram realizados estudos pedológicos, para fins de classificação dos problemas de salinidade do solo em superfície e subsuperfície. Posteriormente, no mesmo lote foram amostrados 45 pontos para avaliação da distribuição espacial da salinidade do solo e diagnóstico do problema de salinidade utilizando análise geoestatística. O índice SI1 em áreas com 'Normalized Difference Vegetation Index' (NDVI) < 0,33 apresentou a maior correlação com a condutividade elétrica do solo. O solo da área avaliada apresentou horizonte salino em superfície e horizonte salino-sódico em subsuperfície. As áreas mais afetadas pela salinidade são áreas côncavas, com deficiência de drenagem natural