Quantum Hamiltonians with Quasi-Ballistic Dynamics and Point Spectrum

Consider the family of Schr\"odinger operators (and also its Dirac version) on $\ell^2(\mathbb{Z})$ or $\ell^2(\mathbb{N})$ $$H^W_{\omega,S}=\Delta + \lambda F(S^n\omega) + W, \quad \omega\in\Omega,$$ where $S$ is a transformation on (compact metric) $\Omega$, $F$ a real Lipschitz function and $W$ a (sufficiently fast) power-decaying perturbation. Under certain conditions it is shown that $H^W_{\omega,S}$ presents quasi-ballistic dynamics for $\omega$ in a dense $G_{\delta}$ set. Applications include potentials generated by rotations of the torus with analytic condition on $F$, doubling map, Axiom A dynamical systems and the Anderson model. If $W$ is a rank one perturbation, examples of $H^W_{\omega,S}$ with quasi-ballistic dynamics and point spectrum are also presented.Comment: 17 pages; to appear in Journal of Differential Equation

Dynamical Delocalization for the 1D Bernoulli Discrete Dirac Operator

An 1D tight-binding version of the Dirac equation is considered; after checking that it recovers the usual discrete Schr?odinger equation in the nonrelativistic limit, it is found that for two-valued Bernoulli potentials the zero mass case presents absence of dynamical localization for specific values of the energy, albeit it has no continuous spectrum. For the other energy values (again excluding some very specific ones) the Bernoulli Dirac system is localized, independently of the mass.Comment: 9 pages, no figures - J. Physics A: Math. Ge

Dynamical Lower Bounds for 1D Dirac Operators

Quantum dynamical lower bounds for continuous and discrete one-dimensional Dirac operators are established in terms of transfer matrices. Then such results are applied to various models, including the Bernoulli-Dirac one and, in contrast to the discrete case, critical energies are also found for the continuous Dirac case with positive mass.Comment: 18 pages; to appear in Math.

Market outlook of mineral-organic fertilizers in Brazil.

The aim of this work is to identify producers of organic-mineral fertilizers in Brazil and analyze the characteristics of the manufactured products

Boron Doses Applied To Soil During Coffee Development

The range between boron deficiency and toxicity in the coffee crop is narrow and the crop toxicity tolerance depends on the soil type, initial soil content and plant age. The objective of this study was to evaluate different levels of boron in the coffee crop during development and grown in a red clayey Oxisol. Treatments consisted of boron applications (zero; 2.48; 4.96; 9.92; 19.8 and 39.68 kg ha-1) in the boric acid form and applied to soil surface in the area of the tree crown projection. The six treatments were outlined in a randomized block design with four replications and ten plants per plot. The cultivar used was Catuaí IAC 144 with sixteen months old, grown in an Oxisol in Campinas, SP, Brazil. Foliar boron content was analyzed as a function of time by regression analysis. The levels in fruit and yield were analyzed by regression according to boron doses. It can be concluded that higher boron doses in the plant can be observed when fruits are at the first development stage. High doses can reduce yield productivity, being each kilogram of applied boron responsible for a reduction of 0.33 coffee bags. ha-1.71495

Spectral and Localization Properties for the One-Dimensional Bernoulli Discrete Dirac Operator

A 1D Dirac tight-binding model is considered and it is shown that its nonrelativistic limit is the 1D discrete Schr?odinger model. For random Bernoulli potentials taking two values (without correlations), for typical realizations and for all values of the mass, it is shown that its spectrum is pure point, whereas the zero mass case presents dynamical delocalization for specific values of the energy. The massive case presents dynamical localization (excluding some particular values of the energy). Finally, for general potentials the dynamical moments for distinct masses are compared, especially the massless and massive Bernoulli cases.Comment: no figure; 24 pages; to appear in Journal of Mathematical Physic

Orthodontic and orthopaedic treatment for anterior open bite in children (Review)

Background: Anterior open bite occurs when there is a lack of vertical overlap of the upper and lower incisors. The aetiology is multifactorial including: oral habits, unfavourable growth patterns, enlarged lymphatic tissue with mouth breathing. Several treatments have been proposed to correct this malocclusion, but interventions are not supported by strong scientific evidence. Objectives: The aim of this systematic review was to evaluate orthodontic and orthopaedic treatments to correct anterior open bite in children. Search methods: The following databases were searched: the Cochrane Oral Health Group's Trials Register (to 14 February 2014); the Cochrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library 2014, Issue 1); MEDLINE via OVID (1946 to 14 February 2014); EMBASE via OVID (1980 to 14 February 2014); LILACS via BIREME Virtual Health Library (1982 to 14 February 2014); BBO via BIREME Virtual Health Library (1980 to 14 February 2014); and SciELO (1997 to 14 February 2014). We searched for ongoing trials via ClinicalTrials.gov (to 14 February 2014). Chinese journals were handsearched and the bibliographies of papers were retrieved. Selection criteria: All randomised or quasi-randomised controlled trials of orthodontic or orthopaedic treatments or both to correct anterior open bite in children. Data collection and analysis: Two review authors independently assessed the eligibility of all reports identified. Risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were calculated for dichotomous data. The continuous data were expressed as described by the author. Main results: Three randomised controlled trials were included comparing: effects of Frankel's function regulator-4 (FR-4) with lip-seal training versus no treatment; repelling-magnet splints versus bite-blocks; and palatal crib associated with high-pull chincup versus no treatment.The study comparing repelling-magnet splints versus bite-blocks could not be analysed because the authors interrupted the treatment earlier than planned due to side effects in four of ten patients.FR-4 associated with lip-seal training (RR = 0.02 (95% CI 0.00 to 0.38)) and removable palatal crib associated with high-pull chincup (RR = 0.23 (95% CI 0.11 to 0.48)) were able to correct anterior open bite.No study described: randomisation process, sample size calculation, there was not blinding in the cephalometric analysis and the two studies evaluated two interventions at the same time. These results should be therefore viewed with caution. Authors' conclusions: There is weak evidence that the interventions FR-4 with lip-seal training and palatal crib associated with high-pull chincup are able to correct anterior open bite. Given that the trials included have potential bias, these results must be viewed with caution. Recommendations for clinical practice cannot be made based only on the results of these trials. More randomised controlled trials are needed to elucidate the interventions for treating anterior open bite

Impactos das mudanças climáticas na produção agrícola e medidas de adaptação sob a percepção de atores e produtores rurais de Nova Friburgo, RJ.

A agricultura é um dos setores mais vulneráveis às mudanças climáticas, devido à dependência intrínseca dos fatores climáticos e recursos naturais, principalmente os agricultores familiares. Os impactos das mudanças climáticas podem ser minimizados por meio de medidas de adaptação adotadas, que devem ser adequadas ao contexto da região. O objetivo é identificar a percepção dos produtores e atores rurais sobre os impactos das mudanças climáticas na produção agrícola, bem como as medidas de adaptação adotadas, analisando também a relação entre a percepção dos produtores e atores rurais e os dados climáticos e da produção agrícola do município de Nova Friburgo, Rio de Janeiro. Os dados resultam de entrevistas aplicadas aos produtores e atores rurais de Nova Friburgo e em base de dados secundários (produção agrícola municipal e dados históricos meteorológicos); eles foram relacionados para identificar a percepção dos entrevistados em relação aos impactos das mudanças climáticas e as medidas de adaptação adotadas. A maioria dos atores rurais e dos produtores convencionais e orgânicos percebe os impactos das mudanças climáticas na produção agrícola; entretanto, não identificou com precisão o ano em que ocorreu o impacto. Predominam as adaptações adotadas do tipo incrementais e coincidem com o que é descrito na literatura científica