Nebular gas drag and planetary accretion with eccentric high-mass planets

Aims.We investigate the dynamics of pebbles immersed in a gas disk interacting with a planet on an eccentric orbit. The model has a prescribed gap in the disk around the location of the planetary orbit, as is expected for a giant planet with a mass in the range of 0.1-1 Jupiter masses. The pebbles with sizes in the range of 1 cm to 3 m are placed in a ring outside of the giant planet orbit at distances between 10 and 30 planetary Hill radii. The process of the accumulation of pebbles closer to the gap edge, its possible implication for the planetary accretion, and the importance of the mass and the eccentricity of the planet in this process are the motivations behind the present contribution. Methods. We used the Bulirsch-Stoer numerical algorithm, which is computationally consistent for close approaches, to integrate the Newtonian equations of the planar (2D), elliptical restricted three-body problem. The angular velocity of the gas disk was determined by the appropriate balance between the gravity, centrifugal, and pressure forces, such that it is sub-Keplerian in regions with a negative radial pressure gradient and super-Keplerian where the radial pressure gradient is positive. Results. The results show that there are no trappings in the 1:1 resonance around the L 4 and L5 Lagrangian points for very low planetary eccentricities (e2 < 0.07). The trappings in exterior resonances, in the majority of cases, are because the angular velocity of the disk is super-Keplerian in the gap disk outside of the planetary orbit and because the inward drift is stopped. Furthermore, the semi-major axis location of such trappings depends on the gas pressure profile of the gap (depth) and is a = 1.2 for a planet of 1 MJ. A planet on an eccentric orbit interacts with the pebble layer formed by these resonances. Collisions occur and become important for planetary eccentricity near the present value of Jupiter (e 2 = 0.05). The maximum rate of the collisions onto a planet of 0.1 MJ occurs when the pebble size is 37.5 cm ≤ s < 75 cm; for a planet with the mass of Jupiter, it is15 cm ≤ s < 30 cm. The accretion stops when the pebble size is less than 2 cm and the gas drag dominates the motion. © 2013 ESO.

Class II malocclusion treatment using high-pull headgear with a splint: a systematic review

Objective: To systematically review the scientific evidence pertaining to the effectiveness of high-pull headgear in growing Class II subjects. Methods: A literature survey was performed by electronic database search. The survey covered the period from January 1966 to December 2008 and used Medical Subject Headings (MeSH). Articles were initially selected based on their titles and abstracts; the full articles were then retrieved. The inclusion criteria included growing subjects between 8 to 15 years of age, Class II malocclusion treatment with high-pull headgear, and a control group with Class II malocclusion. References from selected articles were hand-searched for additional publications. Selected studies were evaluated methodologically. Results: Four articles were selected; none were randomized controlled trials. All of the articles clearly formulated their objectives and used appropriate measures. The studies showed that high-pull headgear treatment improves skeletal and dental relationship, distal displacement of the maxilla, vertical eruption control and upper molars distalization. One of the studies showed a slight clockwise rotation of the palatal plane; the others showed no significant treatment effect. The mandible was not affected by the treatment. Conclusion: While there is still a lack of strong evidence demonstrating the effects of high-pull headgear with a splint, other studies indicate that the AP relations improve due to distalization of the maxilla and upper molars, with little or no treatment effects in the mandible. Greater attention to the design should be given to improve the quality of such trials. © 2013 Dental Press Journal of Orthodontics.

Influência de soluções irrigadoras na resistência adesiva de pinos de fibra de vidro utilizando cimento resinoso: avaliação através do teste de push-out

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aderência aço-concreto: análise numérica dos ensaios pull-out e APULOT

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Assessment of strategies for linking the damage and loss assessment methodology to the post-disaster needs assessment

This report was prepared at the request of the United Nations Economic Commission for Latin America and the Caribbean (ECLAC) with support from the Caribbean Catastrophe Risk Insurance Facility (CCRIF) to assess strategies for linking the ECLAC Damage and Loss Assessment (DaLA) Methology to the Post Disaster Needs Assessment (PDNA). Each metholodolgy was individually outlined and their use in the Caribbean context was explored in detail to set the framework or lens through which their linking would be viewed. Other methologies that are used within the recovery process were identified and outlined. A gap analysis was conducted on moving from the PDNA with a focus on initial rapid reponse to DaLA. DaLA training materials were reviewed to assess where improvements can be made to seamlessly move from one methology to the next. Additionally, both DaLA and PDNA reports were reviewed to identify specific areas of information which could serve as common data links, and note how this linkage could inform the overall disaster assessments in the region. This is in addition to noting any similarities or variance in the application of both methologies. Challenges to linking both methodologies were identified such as countries lacking well defined recovery frameworks and their ability to fund or finance recovery efforts, in addition to recurrent challenges in the Caribbean region such as inadequacy of baseline data, human resource and training, and identifying teams to conduct the data collection. Recommendations made in terms of the strategies to be employed for the successful linking of both the DaLA and PDNA Methodologies included: creating and maintaining a recovery framework and baseline data; creation of a minimum requirements list for the successful implementation of PDNA and DaLA implementation; and increasing political will in addition to identify a champion to push the subject.

É possível gerar “insight” através do ensino dos pré-requisitos por contingências de reforçamento positivo em Rattus norvegicus?

As discussões sobre criatividade indicam uma dificuldade tanto na definição do que seria um padrão “original” ou “criativo” quanto de identificar que variáveis o controlariam. Dentre as interpretações deste fenômeno encontra-se a chamada “interconexão espontânea de repertórios”, quando dois ou mais repertórios diferentes, aprendidos em separado, podem se juntar em novas situações produzindo sequências originais de comportamento. A resolução de um problema de forma súbita através desta interconexão foi denominada de “Insight”. Um dos processos que participariam dessa interconexão seria a “Generalização Funcional”. O presente estudo replicou com algumas mudanças, utilizando três ratos (Rattus norvegicus) como sujeitos (S1, S2 e S3), o trabalho original de Epstein (1985b) e investigou o papel da “Generalização Funcional” na interconexão dos repertórios. Ao S1 e ao S2 foram ensinados separadamente três repertórios distintos. O S1 aprendeu a (1) empurrar um cubo de maneira direcionada, (2) a subir e se erguer sobre cubo e (3) a puxar uma corrente. O S2 aprendeu a (1) empurrar um cubo de maneira não direcionada, (2) a subir e se erguer sobre cubo e a (3) puxar uma corrente. O S3 aprendeu apenas a (1) subir e se erguer sobre cubo e (2) a puxar uma corrente. Após o treino foram colocados numa situaçãoproblema que exigiria a interconexão das habilidades aprendidas para que a resolução ocorresse. O S1 e o S2 resolveram o problema de maneiras distintas: o S1 resolveu de forma aleatória e o S2 resolveu após um treino adicional de subir e puxar a corrente que estabeleceu elos importantes para a resolução. O S3 não resolveu o problema. Os dados indicaram que a generalização funcional poderia ser explicada como generalização simples e que esta não seria um requisito fundamental para a resolução súbita do problema.

Physical fitness in children with probable developmental coordination disorder and normal body mass index

Mudanças no índice de massa corporal (IMC), devido a diversos fatores, como o baixo nível de prática de atividade física, são frequentemente associadas ao baixo nível de aptidão física de crianças com provável transtorno do desenvolvimento da coordenação (pTDC). O presente estudo examinou se crianças com pTDC apresentariam desempenhos inferiores em termos de aptidão física quando comparado com seus pares de desenvolvimento típico (DT). Trinta e duas crianças com pTDC e IMC normal e 32 crianças com DT e IMC normal, pareadas por gênero, idade e IMC, realizaram os testes de sentar e alcançar, de salto horizontal, abdominal, puxada na barra 'modificado' e corrida de 9-min. Os resultados mostraram que crianças do grupo pTDC apresentaram menor força explosiva, resistência e força muscular e resistência cardiorrespiratória do que as crianças do grupo TD. Foi concluído que, mesmo com IMC esperado para a idade, crianças com pTDC têm baixo nível de aptidão física.

Aderência aço-concreto: simulação numéricadosensaios de arranchamento pull-out e APULOT usando o programa ATENA

The bond between steel and concrete is essential for the existence of reinforced concrete structures, as both materials act together to absorb structural strain. The bond phenomenon is considered to be complex regarding many factors that affect it. Several types of bond tests have been proposed over years. One is the modified proposed of pull-out test, which was elaborated by Lorrain and Barbosa [1] called APULOT test (Appropriete pull-out-test). Based on experimental results obtained by Vale Silva[2] either by conventional pull-out tests, or by modified pull-out test, APULOT, seeks to know the numeric behavior of bond steel-concrete through a numerical simulation using a calculation code ATENA which is based on the Finite Element Method (FEM). The numerical simulation provided better evaluate the stress distribution and cracking that occurs during the test, thereby becoming a valuable tool to support the experimental project that aims to validation, validation partially or not recommend the modified bond test steel-concrete - APULOT test - as quality control test of structural concrete. The numerical results showed good representation compared to experimental results.

Influência do uso de hipoclorito de sódio 2,5% e extrato glicólico de sálvia 20% durante o preparo biomecânico sobre a resistência adesiva de retentores intra- radiculares: avaliação através do teste de push-out

The aim of this study it was to evaluate the use of irrigating solution used during root canal preparation on the adhesive cementation of prefabricated fiberglass pins. The bond strength between different regions of the root and the fiberglass pins cemented into the root canal were evaluated by push-out assay. For this study, 36 human teeth were used, all equally prepared. The irrigating solutions used for biomechanical preparation were: saline solution, sodium hypochlorite 2,5% and glycolic extract of salvia 20%. The dual cure resin cement was used for cementation of pins. After cementation, specimens were sectioned to give 3 slices of approximately 2 mm each (cervical, middle and apical), which were submitted to mechanical push-out test. Were performed ANOVA and Tukey's test with a significance level of 5%, for the analysis of mechanical test. Comparing the thirds we observed that the only solution that presented statistical difference in the bond strength was sodium hypochlorite, which showed higher values for the middle and apical third compared with the cervical third, but when compared without taking into consideration the dental thirds, solutions studied showed no differences in bond strength. Therefore, it was concluded that the solutions studied can be used during endodontic treatment without causing harmful effects on the final adhesive restoration

Effectiveness of several solutions to prevent the formation of precipitate due to the interaction between sodium hypochlorite and chlorhexidine and its effect on bond strength of an epoxy-based sealer

To evaluate the effectiveness of isopropyl alcohol, saline or distilled water to prevent the precipitate formed between sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and its effect on the bond strength of an epoxy-based sealer in radicular dentine. Methodology The root canals of 50 extracted human canines (n = 10) were instrumented. In G1, root canals were irrigated with 17% EDTA and 2.5% NaOCl; G2, as G1, except that 2% CHX was used as the final irrigant. In the other groups, intermediate flushes with isopropyl alcohol (G3), saline (G4) or distilled water (G5) were used between NaOCl and CHX. The specimens were submitted to SEM analysis to evaluate the presence of debris and smear layer, in the apical and cervical segments. In sequence, fifty extracted human canines were distributed into five groups (n = 10), similar to the SEM study. After root filling, the roots were sectioned transversally to obtain dentine slices, in the cervical, middle and apical thirds. The root filling was submitted to a push-out bond strength test using an electromechanical testing machine. Statistical analysis was performed using Kruskal–Wallis and Dunn's tests (α = 5%). Results All groups had similar amounts of residue precipitated on the canal walls (P > 0.05). The push-out bond strength values were similar for all groups, independently of the root third evaluated (P > 0.05). Conclusions Isopropyl alcohol, saline and distilled water failed to prevent the precipitation of residues on canal walls following the use of NaOCl and CHX. The residues did not interfere with the push-out bond strength of the root filling.

Effect of calcium hydroxide dressing on push-out bond strength of endodontic sealers to root canal dentin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mechanical and microstructural characterization of laser-welded joints of 6013-T4 aluminum alloy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Insertion Techniques for Resin Cement and Mechanical Cycling on the Bond Strength Between Fiber Posts and Root Dentin

Purpose: To evaluate the effect of the insertion technique for resin cement and mechanical cycling on the bond strength between fiber posts and root dentin.Materials and Methods: Sixty-four single-rooted bovine teeth were endodontically prepared to receive glass-fiber posts. The insertion of cement into the root canal was performed using one of the following techniques: POS, insertion with the post; LEN, the use of a lentulo-type drill; EXP, insertion with a straight-tip explorer; or CEN, the use of a Centrix syringe. Half of the specimens were mechanically cycled. All specimens were sectioned into slices of 1.8 mm for the push-out test and 0.5 mm for analysis of the cement layer quality.Results: The insertion technique affected the interaction between factors (bond strength and mechanical cycling; p < 0.0001). Insertion of the Centrix syringe after mechanical cycling showed the highest bond values (13.6 +/- 3.2 MPa). Group-to-group comparisons for baseline and cycled conditions indicated that mechanical cycling significantly influenced the bond strength (p < 0.0001) of the POS and CEN groups. The quality of the cement layer did not differ between the techniques when evaluated in the middle (p = 0.0612) and cervical (p = 0.1119) regions, but did differ in the apical region (p = 0.0097), where the CEN group had better layer quality for the two conditions tested (baseline and cycled).Conclusion: The use of the Centrix syringe improved the homogeneity of the cement layer, reducing the defects in the layer and increasing adhesive strength values to dentin, even after mechanical cycling.

Effect of metoclopramide, ranitidine, and droperidol on the lower sphincter of the esophagus. Experimental study on the opossum (Didelphis albiventris)

Electromanometric measures of the gastroesophageal junction were performed in 20 adult, male and female, anesthetised opossums. The electromanometric examinations were performed according the intermitent pull through technique. The research was divided in four groups, according to the drug to be analysed: group 1 (20 animals) IM injection of physiological solution (control group); group 2 (20 animals) IM injection of metoclopramide; group 3 (20 animals) IM injection of ranitidine; group 4 (20 animals) IM injection of droperidol. Electromanometry was done 15 minutes before the drug injection, just after the injection and 15, 30, 45 and 60 minutes after the injection. In each one of the moments the pressure of the lower esophageal sphincter (LES-mmHg) was analysed. Considering LES pressure the results observed were: in group 1 it was not observed any significative alteration after IM injection of physiologic solution; in group 2 it was observed significative pressure increase, 15 minutes after metoclopramide IM injection; in group 3 it was observed pressure increase, being significative at 15 and 30 minutes after IM injection; in group 4 it was observed significative increase in LES pressure in every moment, 15 minutes after droperidol IM injection.

Non-centrosymmetric crystals of new N-benzylideneaniline derivatives as potential materials for non-linear optics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)