7 research outputs found
Anisotropic susceptibility of ferromagnetic ultrathin Co films on vicinal Cu
We measure the magnetic susceptibility of ultrathin Co films with an in-plane
uniaxial magnetic anisotropy grown on a vicinal Cu substrate. Above the Curie
temperature the influence of the magnetic anisotropy can be investigated by
means of the parallel and transverse susceptibilities along the easy and hard
axes. By comparison with a theoretical analysis of the susceptibilities we
determine the isotropic exchange interaction and the magnetic anisotropy. These
calculations are performed in the framework of a Heisenberg model by means of a
many-body Green's function method, since collective magnetic excitations are
very important in two-dimensional magnets.Comment: 7 pages, 3 figure
Recent Progress in the Computational Many-Body Theory of Metal Surfaces
In this article we describe recent progress in the computational many-body
theory of metal surfaces, and focus on current techniques beyond the
local-density approximation of density-functional theory. We overview various
applications to ground and excited states. We discuss the exchange-correlation
hole, the surface energy, and the work function of jellium surfaces, as
obtained within the random-phase approximation, a time-dependent
density-functional approach, and quantum Monte Carlo methods. We also present a
survey of recent quasiparticle calculations of unoccupied states at both
jellium and real surfaces.Comment: 17 pages, 1 figure, to appear in Comput. Phys. Commu
Out of hours care: a profile analysis of patients attending the emergency department and the general practitioner on call
<p>Abstract</p> <p>Background</p> <p>Overuse of emergency departments (ED) is of concern in Western society and it is often referred to as 'inappropriate' use. This phenomenon may compromise efficient use of health care personnel, infrastructure and financial resources of the ED. To redirect patients, an extensive knowledge of the experiences and attitudes of patients and their choice behaviour is necessary. The aim of this study is to quantify the patients and socio-economical determinants for choosing the general practitioner (GP) on call or the ED.</p> <p>Methods</p> <p>Data collection was conducted simultaneously in 4 large cities in Belgium. All patients who visited EDs or used the services of the GP on call during two weekends in January 2005 were enrolled in the study in a prospective manner. We used semi-structured questionnaires to interview patients from both services.</p> <p>Results</p> <p>1611 patient contacts were suitable for further analysis. 640 patients visited the GP and 971 went to the ED. Determinants that associated with the choice of the ED are: being male, having visited the ED during the past 12 months at least once, speaking another language than Dutch or French, being of African (sub-Saharan as well as North African) nationality and no medical insurance. We also found that young men are more likely to seek help at the ED for minor trauma, compared to women.</p> <p>Conclusions</p> <p>Patients tend to seek help at the service they are acquainted with. Two populations that distinctively seek help at the ED for minor medical problems are people of foreign origin and men suffering minor trauma. Aiming at a redirection of patients, special attention should go to these patients. Informing them about the health services' specific tasks and the needlessness of technical examinations for minor trauma, might be a useful intervention.</p
Equilibrium Shape of Crystals
This chapter discusses the equilibrium crystal shape (ECS) from a physical
perspective, beginning with a historical introduction to the Wulff theorem. It
takes advantage of excellent prior reviews, particularly in the late 1980's,
recapping highlights from them. It contains many ideas and experiments
subsequent to those reviews. Alternatives to Wulff constructions are presented.
Controversies about the critical behavior near smooth edges on the ECS are
recounted, including the eventual resolution. Particular attention is devoted
to the origin of sharp edges on the ECS, to the impact of reconstructed or
adsorbed surface phases coexisting with unadorned phases, and to the role and
nature of possible attractive step-step interactions.Comment: Review from Handbook of Crystal Growth, Fundamentals, 2nd ed., T.
Nishinaga, ed. (Elsevier, Amsterdam, 2015), vol. 1A (Thermodynamics and
Kinetics), ch. 5, pp. 215-264; ISBN 9780444563699/eBook:9780444593764;
http://www.sciencedirect.com/science/article/pii/B9780444563699000058. 26
figs., reformatted into Phys. Rev. style, 30 pages; slightly modified,
alphabetized bibliography, inc. title
Identification, Localization, and Functional Implications of the Microdomain-Forming Stomatin Family in the Ciliated Protozoan Paramecium tetraurelia
The SPFH protein superfamily is assumed to occur universally in eukaryotes, but information from protozoa is scarce. In the Paramecium genome, we found only Stomatins, 20 paralogs grouped in 8 families, STO1 to STO8. According to cDNA analysis, all are expressed, and molecular modeling shows the typical SPFH domain structure for all subgroups. For further analysis we used family-specific sequences for fluorescence and immunogold labeling, gene silencing, and functional tests. With all family members tested, we found a patchy localization at/near the cell surface and on vesicles. The Sto1p and Sto4p families are also associated with the contractile vacuole complex. Sto4p also makes puncta on some food vacuoles and is abundant on vesicles recycling from the release site of spent food vacuoles to the site of nascent food vacuole formation. Silencing of the STO1 family reduces mechanosensitivity (ciliary reversal upon touching an obstacle), thus suggesting relevance for positioning of mechanosensitive channels in the plasmalemma. Silencing of STO4 members increases pulsation frequency of the contractile vacuole complex and reduces phagocytotic activity of Paramecium cells. In summary, Sto1p and Sto4p members seem to be involved in positioning specific superficial and intracellular microdomain-based membrane components whose functions may depend on mechanosensation (extracellular stimuli and internal osmotic pressure)