3,269 research outputs found
Non-Markovian Dynamics of Quantum Discord
We evaluate the quantum discord dynamics of two qubits in independent and
common non-Markovian environments. We compare the dynamics of entanglement with
that of quantum discord. For independent reservoirs the quantum discord
vanishes only at discrete instants whereas the entanglement can disappear
during a finite time interval. For a common reservoir, quantum discord and
entanglement can behave very differently with sudden birth of the former but
not of the latter. Furthermore, in this case the quantum discord dynamics
presents sudden changes in the derivative of its time evolution which is
evidenced by the presence of kinks in its behavior at discrete instants of
time.Comment: 6 pages, 4 figure
Solitary practices or social connections? : a comparative study of fathering and health experiences among white and African-Caribbean working class men
This study addresses the following research question: what are the implications of African-
Caribbean and White working class men's experiences within social connections (within
families, friendships, communities and workplaces), for fathering and health experiences?
The purposes of this study were to undertake a primary piece of intensive qualitative
research, and also to analyse, critically, the study's findings, in order to identify implications
for theory, policy, practice and research.
This investigation was critical, interpretative and exploratory, informed by the principles of
phenomenology and ethnography. Six African-Caribbean and seven White working class
men were recruited, using purposive sampling, for two semi-structured individual
interviews. This enabled the exploration of the interactive effects and processes of structure
and agency, in relation to social class, gender, and ethnicity.
The study did not find major differences between the experiences of these two groups of
men, although the assets and constraints related to African-Caribbean men's experiences of
ethnicity and racism within social connections were evident. Study findings, for both groups
of men, indicated that social connectedness within families, communities and workplaces
was highly valued, but social connections, material and structural factors also influenced the
health of the men interviewed. Furthermore, findings indicated that men's experiences of
social connectedness have limitations. Specifically, men's limited insights into the links
between social connectedness and health, men's perceived limitations with their
communication skills, their solitary methods of dealing with perceived vulnerability, but
also the uncertainty associated with their identities as men were significant findings. Indeed,
men's experiences of both solitary discourses and practices and social connectedness,
regarding fathering and health, were associated with discourses about masculinities.
Implications for existing theory, for example Connell's (1995) work regarding masculinities,
and Putnam's (1995) work regarding `social capital', are identified. In addition,
implications for research, policy and practice are examined, with specific reference to the
opportunities for mental health promotion with working class men who are fathers
Desenvolvimento de catalisadores magnéticos para despoluição de águas contaminadas com pesticidas.
Fano resonances in plasmonic core-shell particles and the Purcell effect
Despite a long history, light scattering by particles with size comparable
with the light wavelength still unveils surprising optical phenomena, and many
of them are related to the Fano effect. Originally described in the context of
atomic physics, the Fano resonance in light scattering arises from the
interference between a narrow subradiant mode and a spectrally broad radiation
line. Here, we present an overview of Fano resonances in coated spherical
scatterers within the framework of the Lorenz-Mie theory. We briefly introduce
the concept of conventional and unconventional Fano resonances in light
scattering. These resonances are associated with the interference between
electromagnetic modes excited in the particle with different or the same
multipole moment, respectively. In addition, we investigate the modification of
the spontaneous-emission rate of an optical emitter at the presence of a
plasmonic nanoshell. This modification of decay rate due to electromagnetic
environment is referred to as the Purcell effect. We analytically show that the
Purcell factor related to a dipole emitter oriented orthogonal or tangential to
the spherical surface can exhibit Fano or Lorentzian line shapes in the near
field, respectively.Comment: 28 pages, 10 figures; invited book chapter to appear in "Fano
Resonances in Optics and Microwaves: Physics and Application", Springer
Series in Optical Sciences (2018), edited by E. O. Kamenetskii, A. Sadreev,
and A. Miroshnichenk
Avaliação do estado nutricional de bananais em solos de várzea e terra firme do Amazonas.
O objetivo deste trabalho foi de relacionar, a partir da análise foliar, quais os nutrientes mais limitantes para bananicultura no Amazonas, tanto aquela cultivada na várzea, quanto em terra firme
Potencial alelopático de catequinas de Tachigali myrmecophyla (leguminosae).
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