1,368 research outputs found
On Aharonov-Casher bound states
In this work bound states for the Aharonov-Casher problem are considered.
According to Hagen's work on the exact equivalence between spin-1/2
Aharonov-Bohm and Aharonov-Casher effects, is known that the
term cannot be neglected in the
Hamiltonian if the spin of particle is considered. This term leads to the
existence of a singular potential at the origin. By modeling the problem by
boundary conditions at the origin which arises by the self-adjoint extension of
the Hamiltonian, we derive for the first time an expression for the bound state
energy of the Aharonov-Casher problem. As an application, we consider the
Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the
expression for the harmonic oscillator energies and compare it with the
expression obtained in the case without singularity. At the end, an approach
for determination of the self-adjoint extension parameter is given. In our
approach, the parameter is obtained essentially in terms of physics of the
problem.Comment: 11 pages, matches published versio
Determining factors of functioning in hemodialysis patients using the international classification of functioning, disability and health
Background: Hemodialysis (HD) treatment affects functioning, physical activity level, clinical biomarkers, and body
composition. However, the association between these variables with functioning, considering International Classification
of Functioning, Disability and Health (ICF) domains remains unclear. Thus, the aim of this study was to investigate
the possible association between physical activity, biomarkers, and body composition with functioning in HD patients
in reference to the ICF.
Methods: Eighty HD patients performed different tests grouped according to ICF domain: Body structure and function
– handgrip strength (HS), 5-repetition sit-to-stand test, and 60-s sit-to-stand test (5-STS, 60-STS, respectively);
Activity – short physical performance battery (SPPB); and Participation – participation scale questionnaire. Physical
activity [Human Activity Profile questionnaire (HAP)], body composition (Dual-energy X-ray absorptiometry), Parathormone
(PTH), and alkaline phosphatase were analyzed as possible variables associated with ICF domains. Data analyses
were performed using simple and multiple regression models adjusted for age, duration of HD, and diuresis volume.
Results: In the body structure and function domain, appendicular lean mass, PTH level, and age were associated
with HS (
R2 = 0.558); HAP and PTH were associated with 5-STS (
R2 = 0.263); and HAP, PTH, duration of HD, and age
were associated with 60-STS (
R2 = 0.337). In the activity domain, HAP, PTH, alkaline phosphatase, duration of HD, age,
and body fat were associated with SPPB (
R2 = 0.689). Finally, only HAP was associated with the participation scale
(
R2 = 0.067).
Conclusion: Physical activity and PTH levels are determinant protagonists of functioning in all ICF domains in hemodialysis
patients
Chemical profile and biological activities of essential oil from Artemisia vulgaris L. cultivated in Brazil
Essential oil from the leaves of Artemisia vulgaris L. (Compositae) cultivated in Brazil was investigated for its chemical composition and biological activities including antibacterial, antifungal, and anthelmintic. The constituents of essential oils isolated by hydro-distillation were examined by GC-MS and a total of 18 components were identified. The essential oil was dominated by oxygenated sesquiterpenes (44.4%), sesquiterpene hydrocarbons (33.3%), and oxygenated monoterpenes (16.6%). Caryophyllene (37.45%), germacrene D (16.17%), and humulene (13.66%) were the major components. The essential oils from A. vulgaris showed bactericidal and fungicidal properties against Staphylococcus aureus and Candida albicans, respectively. Anthelmintic activity against Haemonchus contortus was absent in this essential oil. Altogether above results indicate that essential oils from A. vulgaris can be used for various medicinal purposes.Sonia Malik, Ludmilla Santos Silva de Mesquita, Carolina Rocha Silva, José Wilson Carvalho de Mesquita, Emmeline de Sá Rocha, Jayakumar Bose, Rambod Abiri, Patricia de Maria Silva Figueiredo, and Livio M. Costa-Júnio
Avaliação de modelos para estimação de componentes de (co)variância em características de desempenho e reprodutivas em suínos
Importance of anatomical leaf features for characterization of three species of Mapania (Mapanioideae, Cyperaceae) from the Amazon Forest, Brazil
Avaliação sensorial de uvas de mesa produzidas no Vale do São Francisco e comercializadas em João Pessoa - PB
Typification and authorship of Drosera intermedia (Droseraceae)
Drosera intermedia is lectotypified with the herbarium specimen on which the type drawing in the 1798 protologue was based. The collection history of the specimen, the history of the botanical drawing as original material, and the correct nomenclatural author and publication date of the name are presented based on historical notes and literature. Additionally, the global distribution of the species is given, including the first record from Africa
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In the last years many populations of anurans have declined and extinctions have been recorded. They were related to environmental pollution, changes of land use and emerging diseases. The main objective of this study was to determine copper sensitivity of the anuran of the Amazon Rhinella granulosa and Scinax ruber tadpoles at stage 25 and Scinax ruber eggs exposed for 96 h to copper concentrations ranging from 15 µg Cu L-1 to 94 µg Cu L-1. LC50 at 96 h of Rhinella granulosa Gosner 25, Scinax ruber Gosner 25 and Scinax ruber eggs in black water of the Amazon were 23.48, 36.37 and 50.02 µg Cu L-1, respectively. The Biotic Ligand Model was used to predict the LC50 values for these species and it can be considered a promising tool for these tropical species and water conditions. Copper toxicity depends on water physical-chemical composition and on the larval stage of the tadpoles. The Gosner stage 19-21 (related to the appearance of external gills) is the most vulnerable and the egg stage is the most resistant. In case of contamination by copper, the natural streams must have special attention, since copper is more bioavailable.Nos últimos anos foram registrados muitas extinções e declínios de populações de anuros. Eles estavam relacionados com a poluição do ambiente, a mudanças no uso da terra e ao surgimento de doenças. O principal objetivo deste estudo foi determinar a sensibilidade dos anuros amazônicos ao cobre. Os girinos de Scinax ruber e Rhinella granulosa no estadio 25 e os ovos de Scinax ruber foram expostos por 96 horas a concentrações de cobre entre 15 µg Cu L-1 a 94 µg Cu L-1. A CL50 -96 h dos girinos de Rhinella granulosa, dos girinos de Scinax ruber e dos ovos de Scinax ruber em águas pretas da Amazônia foram 23,48; 36,37 e 50,02 µg Cu L-1, respectivamente. O modelo do ligante biótico foi usado para prever os valores de CL50 para essas duas espécies e pode ser considerado uma ferramenta promissora para essas espécies tropicais e para essas condições de água. A Toxicidade de cobre depende da composição físico-química da água e do estagio larval dos girinos. O estadio 19-21 de Gosner (relacionados ao aparecimento das brânquias externas) são os mais vulnerável e o estagio de ovo é o mais resistente. Em caso de contaminação por cobre, os igarapés naturais devem ter uma atenção especial, uma vez que o cobre é mais biodisponível nesse ambiente
Abundances of the elements in the solar system
A review of the abundances and condensation temperatures of the elements and
their nuclides in the solar nebula and in chondritic meteorites. Abundances of
the elements in some neighboring stars are also discussed.Comment: 42 pages, 11 tables, 8 figures, chapter, In Landolt- B\"ornstein, New
Series, Vol. VI/4B, Chap. 4.4, J.E. Tr\"umper (ed.), Berlin, Heidelberg, New
York: Springer-Verlag, p. 560-63
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