10,507 research outputs found
The concept of social pharmacy
The 13th International Social Pharmacy Workshop will be held in Malta in July 2004. The Social Pharmacy Workshops are international conferences for research in social and behavioural pharmacy. Meetings are held every second year and participation has grown steadily since the first Workshop was held in Helsinki, Finland, in 1980. Following the successful 2002 conference in Sydney, Australia, the 2004 meeting in Malta will be the first one held in the Mediterranean area!peer-reviewe
Different quantization mechanisms in single-electron pumps driven by surface acoustic waves
We have studied the acoustoelectric current in single-electron pumps driven
by surface acoustic waves. We have found that in certain parameter ranges two
different sets of quantized steps dominate the acoustoelectric current versus
gate-voltage characteristics. In some cases, both types of quantized steps
appear simultaneously though at different current values, as if they were
superposed on each other. This could indicate two independent quantization
mechanisms for the acoustoelectric current.Comment: 6 pages, 3 figure
Entrance and survival of <i>Brucella pinnipedialis</i> hooded seal strain in human macrophages and epithelial cells
Marine mammal Brucella spp. have been isolated from pinnipeds (B. pinnipedialis) and cetaceans (B. ceti) from around the world. Although the zoonotic potential of marine mammal brucellae is largely unknown, reports of human disease exist. There are few studies of the mechanisms of bacterial intracellular invasion and multiplication involving the marine mammal Brucella spp. We examined the infective capacity of two genetically different B. pinnipedialis strains (reference strain; NTCT 12890 and a hooded seal isolate; B17) by measuring the ability of the bacteria to enter and replicate in cultured phagocytes and epithelial cells. Human macrophage-like cells (THP-1), two murine macrophage cell lines (RAW264.7 and J774A.1), and a human malignant epithelial cell line (HeLa S3) were challenged with bacteria in a gentamicin protection assay. Our results show that B. pinnipedialis is internalized, but is then gradually eliminated during the next 72 – 96 hours. Confocal microscopy revealed that intracellular B. pinnipedialis hooded seal strain colocalized with lysosomal compartments at 1.5 and 24 hours after infection. Intracellular presence of B. pinnipedialis hooded seal strain was verified by transmission electron microscopy. By using a cholesterol-scavenging lipid inhibitor, entrance of B. pinnipedialis hooded seal strain in human macrophages was significantly reduced by 65.8 % (± 17.3), suggesting involvement of lipid-rafts in intracellular entry. Murine macrophages invaded by B. pinnipedialis do not release nitric oxide (NO) and intracellular bacterial presence does not induce cell death. In summary, B. pinnipedialis hooded seal strain can enter human and murine macrophages, as well as human epithelial cells. Intracellular entry of B. pinnipedialis hooded seal strain involves, but seems not to be limited to, lipid-rafts in human macrophages. Brucella pinnipedialis does not multiply or survive for prolonged periods intracellulary
Observation of modified hadronization in relativistic Au+Au collisions: a promising signature for deconfined quark-gluon matter
Measurements of identified particles from Au+Au collisions at
GeV are reviewed. Emphasis is placed on nuclear
modification, baryon-to-meson ratios, and elliptic flow at intermediate
transverse momentum ( GeV/c). Possible connections between (1)
these measurements, (2) the running coupling for static quark anti-quark pairs
at finite temperature, and (3) the creation of a deconfined quark-gluon phase
are presented. Modifications to hadronization in Au+Au collisions are proposed
as a likely signature for the creation of deconfined colored matter.Comment: 8 pages, 5 figures, invited talk at the Strange Quark Matter 2004
conference, Cape Town, South Afric
Toward Quantum Superposition of Living Organisms
The most striking feature of quantum mechanics is the existence of
superposition states, where an object appears to be in different situations at
the same time. The existence of such states has been tested with small objects,
like atoms, ions, electrons and photons, and even with molecules. More
recently, it has been possible to create superpositions of collections of
photons, atoms, or Cooper pairs. Current progress in optomechanical systems may
soon allow us to create superpositions of even larger objects, like micro-sized
mirrors or cantilevers, and thus to test quantum mechanical phenomena at larger
scales. Here we propose a method to cool down and create quantum superpositions
of the motion of sub-wavelength, arbitrarily shaped dielectric objects trapped
inside a high--finesse cavity at a very low pressure. Our method is ideally
suited for the smallest living organisms, such as viruses, which survive under
low vacuum pressures, and optically behave as dielectric objects. This opens up
the possibility of testing the quantum nature of living organisms by creating
quantum superposition states in very much the same spirit as the original
Schr\"odinger's cat "gedanken" paradigm. We anticipate our essay to be a
starting point to experimentally address fundamental questions, such as the
role of life and consciousness in quantum mechanics.Comment: 9 pages, 4 figures, published versio
Bond-versus-site doping models for off-chain-doped Haldane-gap system Y Ba Ni O
Using the density matrix renormalization-group technique, we calculate the
impurity energy levels for two different effective models of off-chain doping
for quasi-one-dimensional Heisenberg chain compound Y Ba Ni O:
ferromagnetic bond doping and antiferromagnetic site spin-1/2 doping.
Thresholds of the impurity strength for the appearance of localized states are
found for both models. However, the ground-state and low-energy excitations for
weak impurity strength are different for these two models and the difference
can be detected by experiments.Comment: 5 pages, 5 eps figures included, to be published in Phys. Rev.
Fluctuation and flow probes of early-time correlations in relativistic heavy ion collisions
Fluctuation and correlation observables are often measured using
multi-particle correlation methods and therefore mutually probe the origins of
genuine correlations present in multi-particle distribution functions. We
investigate the common influence of correlations arising from the spatially
inhomogeneous initial state on multiplicity and momentum fluctuations as well
as flow fluctuations. Although these observables reflect different aspects of
the initial state, taken together, they can constrain a correlation scale set
at the earliest moments of the collision. We calculate both the correlation
scale in an initial stage Glasma flux tube picture and the modification to
these correlations from later stage hydrodynamic flow and find quantitative
agreement with experimental measurements over a range of collision systems and
energies.Comment: Proceedings of the 28th Winter Workshop on Nuclear Dynamics, Dorado
del Mar, Puerto Rico, April 7-14, 201
Superconductor-insulator transition driven by local dephasing
We consider a system where localized bound electron pairs form an array of
"Andreev"-like scattering centers and are coupled to a fermionic subsystem of
uncorrelated electrons. By means of a path-integral approach, which describes
the bound electron pairs within a coherent pseudospin representation, we derive
and analyze the effective action for the collective phase modes which arise
from the coupling between the two subsystems once the fermionic degrees of
freedom are integrated out. This effective action has features of a quantum
phase model in the presence of a Berry phase term and exhibits a coupling to a
field which describes at the same time the fluctuations of density of the bound
pairs and those of the amplitude of the fermion pairs. Due to the competition
between the local and the hopping induced non-local phase dynamics it is
possible, by tuning the exchange coupling or the density of the bound pairs, to
trigger a transition from a phase ordered superconducting to a phase disordered
insulating state. We discuss the different mechanisms which control this
occurrence and the eventual destruction of phase coherence both in the weak and
strong coupling limit.Comment: 16 pages, 5 figures, submitted to PRB (05-Feb04
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