59,977 research outputs found
Making co-enrolment feasible for randomised controlled trials in paediatric intensive care.
Enrolling children into several trials could increase recruitment and lead to quicker delivery of optimal care in paediatric intensive care units (PICU). We evaluated decisions taken by clinicians and parents in PICU on co-enrolment for two large pragmatic trials: the CATCH trial (CATheters in CHildren) comparing impregnated with standard central venous catheters (CVCs) for reducing bloodstream infection in PICU and the CHIP trial comparing tight versus standard control of hyperglycaemia
Magnetic Phase Transitions in One-dimensional Strongly Attractive Three-Component Ultracold Fermions
We investigate the nature of trions, pairing and quantum phase transitions in
one-dimensional strongly attractive three-component ultracold fermions in
external fields. Exact results for the groundstate energy, critical fields,
magnetization and phase diagrams are obtained analytically from the Bethe
ansatz solutions. Driven by Zeeman splitting, the system shows exotic phases of
trions, bound pairs, a normal Fermi liquid and four mixtures of these states.
Particularly, a smooth phase transition from a trionic phase into a pairing
phase occurs as the highest hyperfine level separates from the two lower energy
levels. In contrast, there is a smooth phase transition from the trionic phase
into a normal Fermi liquid as the lowest level separates from the two higher
levels.Comment: 4 pages, 3 figures, minor revisions to text, replacement figure, refs
added and update
Relations Between Low-lying Quantum Wave Functions and Solutions of the Hamilton-Jacobi Equation
We discuss a new relation between the low lying Schroedinger wave function of
a particle in a one-dimentional potential V and the solution of the
corresponding Hamilton-Jacobi equation with -V as its potential. The function V
is , and can have several minina (V=0). We assume the problem to be
characterized by a small anhamornicity parameter and a much smaller
quantum tunneling parameter between these different minima.
Expanding either the wave function or its energy as a formal double power
series in and , we show how the coefficients of
in such an expansion can be expressed in terms of definite
integrals, with leading order term determined by the classical solution of the
Hamilton-Jacobi equation. A detailed analysis is given for the particular
example of quartic potential .Comment: LaTex, 48 pages, no figur
When resources collide: Towards a theory of coincidence in information spaces
This paper is an attempt to lay out foundations for a general theory of coincidence in information spaces such as the World Wide Web, expanding on existing work on bursty structures in document streams and information cascades. We elaborate on the hypothesis that every resource that is published in an information space, enters a temporary interaction with another resource once a unique explicit or implicit reference between the two is found. This thought is motivated by Erwin Shroedingers notion of entanglement between quantum systems. We present a generic information cascade model that exploits only the temporal order of information sharing activities, combined with inherent properties of the shared information resources. The approach was applied to data from the world's largest online citizen science platform Zooniverse and we report about findings of this case study
Wilson ratio of Fermi gases in one dimension
We calculate the Wilson ratio of the one-dimensional Fermi gas with spin
imbalance. The Wilson ratio of attractively interacting fermions is solely
determined by the density stiffness and sound velocity of pairs and of excess
fermions for the two-component Tomonaga-Luttinger liquid (TLL) phase. The ratio
exhibits anomalous enhancement at the two critical points due to the sudden
change in the density of states. Despite a breakdown of the quasiparticle
description in one dimension, two important features of the Fermi liquid are
retained, namely the specific heat is linearly proportional to temperature
whereas the susceptibility is independent of temperature. In contrast to the
phenomenological TLL parameter, the Wilson ratio provides a powerful parameter
for testing universal quantum liquids of interacting fermions in one, two and
three dimensions.Comment: 5+2 pages, 4+1 figures, Eq. (4) is proved, figures were refine
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