On an atom with a magnetic quadrupole moment in a rotating frame

The quantum description of an atom with a magnetic quadrupole moment in the presence of a uniform effective magnetic field is analysed. The atom is also subject to rotation and a scalar potential proportional to the inverse of the radial distance. It is shown that the spectrum of energy is modified, in contrast to the Landau-type levels, and there is a restriction on the possible values of the cyclotron frequency which stems from the influence of the rotation and scalar potential proportional to the inverse of the radial distance.Comment: 11 pages. arXiv admin note: text overlap with arXiv:1705.0819

Exploring Practitioners’ Pedagogic Stances in Relation to Integrated Guidance: A Q-Method Study

Using Q-method, this article explores how experience with integrated guidance frames practitioners’ pedagogic stances. Integrated guidance is an approach to delivering career guidance that combines face-to-face and digital approaches. Through statistical analysis of participants’ Q-sorts and qualitative interpretation of the results, we identify three groups of participants with different philosophies about integrated guidance and, consequently, different strategies and approaches to guidance. All groups recognise that blended learning pedagogy is useful in career guidance and believe that digital information, guidance tools and platforms can benefit clients in their career learning. However, there are also differences between the groups. The first group (enthusiasts) view the digital environment positively and are confident about their ability to adapt and apply emerging technologies in guidance. The second group (human connectors) prefer face-to-face approaches, especially for clients with low digital skills; they view the digital environment as potentially hostile and have concerns about their abilities to adapt to new guidance technologies. The third group (critical pragmatists) are confident in using digital technologies for guidance but believe that the digital environment can be hostile while recognising its potential as a site for their clients’ career development. These different groups are theorised and display three distinct pedagogic stances on integrated guidance

Hatching Strategies in Monogenean (Platyhelminth) Parasites that Facilitate Host Infection

In parasites, environmental cues may influence hatching of eggs and enhance the success of infections. The two major endoparasitic groups of parasitic platyhelminths, cestodes (tapeworms) and digeneans (flukes), typically have high fecundity, infect more than one host species, and transmit trophically. Monogeneans are parasitic flatworms that are among the most host specific of all parasites. Most are ectoparasites with relatively low fecundity and direct life cycles tied to water. They infect a single host species, usually a fish, although some are endoparasites of amphibians and aquatic chelonian reptiles. Monogenean eggs have strong shells and mostly release ciliated larvae, which, against all odds, must find, identify, and infect a suitable specific host. Some monogeneans increase their chances of finding a host by greatly extending the hatching period (possible bet-hedging). Others respond to cues for hatching such as shadows, chemicals, mechanical disturbance, and osmotic changes, most of which may be generated by the host. Hatching may be rhythmical, larvae emerging at times when the host is more vulnerable to invasion, and this may be combined with responses to other environmental cues. Different monogenean species that infect the same host species may adopt different strategies of hatching, indicating that tactics may be more complex than first thought. Control of egg assembly and egg-laying, possibly by host hormones, has permitted colonization of frogs and toads by polystomatid monogeneans. Some monogeneans further improve the chances of infection by attaching eggs to the host or by retaining eggs on, or in, the body of the parasite. The latter adaptation has led ultimately to viviparity in gyrodactylid monogeneans

Agrofloresta no Semiárido cearense: uma experiência de sucesso no município de Nova Olinda.

Os Sistemas Agroflorestais foram inicialmente utilizados pelos povos indígenas. Atualmente, são desenvolvidos principalmente nas regiões tropicais e subtropicais do planeta. Caracterizam-se pela introdução e mistura de árvores ou arbustos nos campos de produção agrícola ou pecuária, proporcionando vários benefícios a partir das interações ecológicas e econômicas que se desenvolvem nesse processo. Este trabalho teve como objetivo mostrar a importância da implantação de um sistema agroflorestal, através do relato da experiência no Sítio Taboleiro, no município de Nova Olinda, no Cariri cearense, descrevendo como O SAF foi introduzido pelo Sr. Zé Arthur, e como o agricultor vê o desenvolvimento desse sistema na referida região. O trabalho foi realizado em junho de 2012. Utilizou-se como metodologia de pesquisa entrevista semiestruturada com o proprietário, gravada em mp3 uma e fez-se ainda aplicação de questionário. Os resultados positivos apresentados pelo sistema agroflorestal desenvolvido por Zé Arthur revelam que essa prática agroecológica apresentou melhores resultados que a agricultura a agricultura convencional desenvolvida em outras propriedades no município de Nova Olinda-CE. Além de ser um perfeito exemplo de produção sustentável, o SAF do Senhor Zé Arthur também vem sendo uma das atrações do roteiro turístico do município de Nova Olinda

Tame concealed algebras and cluster quivers of minimal infinite type

In this paper we explain how and why the list of Happel-Vossieck of tame concealed algebras is closely related to the list of A. Seven of minimal infinite cluster quivers.Comment: 16 pages, new version with an additional section on cluster-tilted algebras of minimal infinite typ

Resolution of the Klein Paradox

We present a resolution of the Klein paradox within the framework of one-particle relativistic quantum mechanics. Not only reflection becomes total but the vacuum remains neutral as well. This is accomplished by replacing the pair production process with virtual negative energy "incidence" within the barrier in a similar manner to what is done with image charges in electrostatic and virtual sources in optics.Comment: 9 pages, 8 figure

Noninertial effects on a Dirac neutral particle inducing an analogue of the Landau quantization in the cosmic string spacetime

We discuss the behaviour of external fields that interact with a Dirac neutral particle with a permanent electric dipole moment in order to achieve relativistic bound states solutions in a noninertial frame and in the presence of a topological defect spacetime. We show that the noninertial effects of the Fermi-Walker reference frame induce a radial magnetic field even in the absence of magnetic charges, which is influenced by the topology of the cosmic string spacetime. We then discuss the conditions that the induced fields must satisfy to yield the relativistic bound states corresponding to the Landau-He-McKellar-Wilkens quantization in the cosmic string spacetime. Finally we obtain the Dirac spinors for positive-energy solutions and the Gordon decomposition of the Dirac probability current.Comment: 15 pages, no figure, this paper will be published in volume 42 of the Brazilian Journal of Physic

Tilted algebras and short chains of modules

We provide an affirmative answer for the question raised almost twenty years ago concerning the characterization of tilted artin algebras by the existence of a sincere finitely generated module which is not the middle of a short chain