Tensor coupling and pseudospin symmetry in nuclei

In this work we study the contribution of the isoscalar tensor coupling to the realization of pseudospin symmetry in nuclei. Using realistic values for the tensor coupling strength, we show that this coupling reduces noticeably the pseudospin splittings, especially for single-particle levels near the Fermi surface. By using an energy decomposition of the pseudospin energy splittings, we show that the changes in these splittings come by mainly through the changes induced in the lower radial wave function for the low-lying pseudospin partners, and by changes in the expectation value of the pseudospin-orbit coupling term for surface partners. This allows us to confirm the conclusion already reached in previous studies, namely that the pseudospin symmetry in nuclei is of a dynamical nature.Comment: 11 pages, 5 figures, uses REVTeX macro

Relevance of pseudospin symmetry in proton-nucleus scattering

The manifestation of pseudospin-symmetry in proton-nucleus scattering is discussed. Constraints on the pseudospin-symmetry violating scattering amplitude are given which require as input cross section and polarization data, but no measurements of the spin rotation function. Application of these constraints to p-58Ni and p-208Pb scattering data in the laboratory energy range of 200 MeV to 800 MeV, reveals a significant violation of the symmetry at lower energies and a weak one at higher energies. Using a schematic model within the Dirac phenomenology, the role of the Coulomb potential in proton-nucleus scattering with regard to pseudospin symmetry is studied. Our results indicate that the existence of pseudospin-symmetry in proton-nucleus scattering is questionable in the whole energy region considered and that the violation of this symmetry stems from the long range nature of the Coulomb interaction.Comment: 22 pages including 9 figures, correction of 1 reference, revision of abstract and major modification of chapter 4, Fig. 6, and Fig. 7; addition of Fig. 8 and Fig.

Relating pseudospin and spin symmetries through charge conjugation and chiral transformations: the case of the relativistic harmonic oscillator

We solve the generalized relativistic harmonic oscillator in 1+1 dimensions, i.e., including a linear pseudoscalar potential and quadratic scalar and vector potentials which have equal or opposite signs. We consider positive and negative quadratic potentials and discuss in detail their bound-state solutions for fermions and antifermions. The main features of these bound states are the same as the ones of the generalized three-dimensional relativistic harmonic oscillator bound states. The solutions found for zero pseudoscalar potential are related to the spin and pseudospin symmetry of the Dirac equation in 3+1 dimensions. We show how the charge conjugation and $\gamma^5$ chiral transformations relate the several spectra obtained and find that for massless particles the spin and pseudospin symmetry related problems have the same spectrum, but different spinor solutions. Finally, we establish a relation of the solutions found with single-particle states of nuclei described by relativistic mean-field theories with scalar, vector and isoscalar tensor interactions and discuss the conditions in which one may have both nucleon and antinucleon bound states.Comment: 33 pages, 10 figures, uses revtex macro

'Diverse mobilities': second-generation Greek-Germans engage with the homeland as children and as adults

This paper is about the children of Greek labour migrants in Germany. We focus on two life-stages of ‘return’ for this second generation: as young children brought to Greece on holidays or sent back for longer periods, and as young adults exercising an independent ‘return’ migration. We draw both on literature and on our own field interviews with 50 first- and second-generation Greek-Germans. We find the practise of sending young children back to Greece to have been surprisingly widespread yet little documented. Adult relocation to the parental homeland takes place for five reasons: (i) a ‘search for self’; (ii) attraction of the Greek way of life; (iii) the actualisation of the ‘family narrative of return’ by the second, rather than the first, generation; (iv) life-stage events such as going to university or marrying a Greek; (v) escape from a traumatic event or oppressive family situation. Yet the return often brings difficulties, disillusionment, identity reappraisal, and a re-evaluation of the German context

Jasmonic acid and K-phosphite enhance productivity and technological quality of sugarcane crop.

Abstract: Plant resistance inducers are cost-effective and environmentally pleasing strategies of plant protection to mitigate biotic and abiotic agents threatening food safety and energy security. We, accordingly, present jasmonic acid and k-phosphite as low-cost strategies to enhance productive yield and technological quality of sugarcane crop. Exogenously treatment of the sugarcane variety SP81-3250 consisted of carrying out foliar application of jasmonic acid at 1, 1.5 and 2 ml L-1 and K-phosphite at 2, 4 and 6 ml L-1 before crop flowering. Interestingly, both systemic phytorregulator and foliar fertilizer at the lowest doses significantly improved contents of total soluble solids and sucrose, as well as productive yield of fermentable sugars. Jasmonic acid could promote growth and development by triggering either non-enzymatic or enzymatic mechanisms in the host self-defense system to support of external stresses, including herbivory by sugarcane-borer. K-phosphite could improve crop performance by not only releasing water-soluble inorganic ions like phosphorus and potash, but also by signaling synthesis of phytoalexins. Purity of cane juice and productivity of stalks sharply decreased, as the doses of the plant-resistance inducers increased. Jasmonic acid and k-phosphite at unbalanced endogenous levels could inhibit physiological ripening and specific enzymatical activity of alkaline invertases and sucrose-phosphate synthase, thereby influencing bioavailability of sucrose. The lower the sucrose content, the poorer the technological quality of sugarcane crop. The conclusion is, therefore, jasmonic acid and K-phosphite at lower doses prove to be effective induced resistance techniques to produce richer feedstock, with potential to produce ethanol fuel and refined sugar in sugar-energy plants

Sensibilidad de la microestructura en un sistema multi-escala

Este trabajo analiza la sensibilidad de los parámetros de optimización de una microestructura periódica isotrópica en la optimización topológica de una viga MBB. La función objetivo para optimización de la microestructura es el módulo volumétrico, y los parámetros analizados son: fracción volumétrica, radio de filtro y factor de penalización. En la macroestructura la función objetivo es la minimización de la flexibilidad, sujeta a un volumen predefinido de 0.5. Se desarrolló un algoritmo, con base en el método SIMP, capaz de transferir las informaciones de la microestructura para la macroestructura. Se realizaron análisis numéricos, variando los parámetros y observando el comportamiento de las soluciones. Los resultados demuestran que la fracción volumétrica de la microestructura tiene gran influencia en la maximización de la rigidez, sin embargo el radio de filtro y el factor de penalización presentaron poca influencia, así como sobre el perfil de la macroestructura.Publicado en: Mecánica Computacional vol. XXXV, no. 23Facultad de Ingenierí

Sensibilidad de la microestructura en un sistema multi-escala

Este trabajo analiza la sensibilidad de los parámetros de optimización de una microestructura periódica isotrópica en la optimización topológica de una viga MBB. La función objetivo para optimización de la microestructura es el módulo volumétrico, y los parámetros analizados son: fracción volumétrica, radio de filtro y factor de penalización. En la macroestructura la función objetivo es la minimización de la flexibilidad, sujeta a un volumen predefinido de 0.5. Se desarrolló un algoritmo, con base en el método SIMP, capaz de transferir las informaciones de la microestructura para la macroestructura. Se realizaron análisis numéricos, variando los parámetros y observando el comportamiento de las soluciones. Los resultados demuestran que la fracción volumétrica de la microestructura tiene gran influencia en la maximización de la rigidez, sin embargo el radio de filtro y el factor de penalización presentaron poca influencia, así como sobre el perfil de la macroestructura.Publicado en: Mecánica Computacional vol. XXXV, no. 23Facultad de Ingenierí

Doença de Behçet: a nossa realidade

Introdução: A doença de Behçet é uma vasculite inflamatória sistémica, de etiologia desconhecida, caraterizada por episódios de recidiva de úlceras orais e genitais, lesões oculares e cutâneas, podendo atingir virtualmente todos os sistemas. As manifestações oculares são comuns e com consequências visuais importantes. O objectivo deste trabalho foi analisar os parâmetros demográficos, manifestações clinicas, terapêutica e principais complicações em doentes com doença de Behçet ocular. Métodos: Estudo descritivo e retrospetivo, que incluiu 11 doentes com o diagnóstico de doença de Behçet, segundo os critérios do ISG, observados na consulta de Inflamação Ocular do Hospital Prof. Doutor Fernando da Fonseca nos últimos 3 anos. Resultados: Identificaram-se 11 doentes, 5 homens e 6 mulheres, todos caucasianos. A idade média ao diagnóstico foi de 33,45±6,49 anos. A manifestação ocular foi o primeiro sinal da doença em 2 doentes. Em 72,7% dos casos as manifestações oculares foram bilaterais. Identificaram-se 4 casos de panuveíte, 3 de uveíte posterior, 2 de uveíte anterior, 1 de queratite e 1 caso de episclerite. O glaucoma e a catarata foram a complicação ocular mais frequente. O tratamento sistémico incluiu a corticoterapia oral em associação com terapêutica adjuvante imunossupressora, sendo os mais utilizados a azatioprina e a ciclosporina. Em 3 doentes houve necessidade de terapêutica biológica com infliximab para controlo da doença. Conclusão: A manifestação ocular mais frequente foi a panuveite. Esta doença pode condicionar complicações oculares com diminuição irreversível da acuidade visual. A orientação destes doentes exige uma abordagem global e inter-disciplinar