864 research outputs found
Swinging Atwood's Machine: Experimental and Theoretical Studies
A Swinging Atwood Machine (SAM) is built and some experimental results
concerning its dynamic behaviour are presented. Experiments clearly show that
pulleys play a role in the motion of the pendulum, since they can rotate and
have non-negligible radii and masses. Equations of motion must therefore take
into account the inertial momentum of the pulleys, as well as the winding of
the rope around them. Their influence is compared to previous studies. A
preliminary discussion of the role of dissipation is included. The theoretical
behaviour of the system with pulleys is illustrated numerically, and the
relevance of different parameters is highlighted. Finally, the integrability of
the dynamic system is studied, the main result being that the Machine with
pulleys is non-integrable. The status of the results on integrability of the
pulley-less Machine is also recalled.Comment: 37 page
Rare charm meson decays D->Pl^+l^- and c->ul^+l^- in SM and MSSM
We study the nine possible rare charm meson decays D->Pl^+l^-
(P=pi,K,eta,eta') using the Heavy Meson Chiral Lagrangians and find them to be
dominated by the long distance contributions. The decay D^+ -> pi^+l^+l^- with
the branching ratio 1*10^(-6) is expected to have the best chances for an early
experimental discovery. The short distance contribution in the five Cabibbo
suppressed channels arises via the c->ul^+l^- transition; we find that this
contribution is detectable only in the D->pi l^+l^- decay, where it dominates
the differential spectrum at high-q^2. The general Minimal Supersymmetric
Standard Model can enhance the c->ul^+l^- rate by up to an order of magnitude;
its effect on the D->Pl^+l^- rates is small since the c->ul^+l^- enhancement is
sizable in low-q^2 region, which is inhibited in the hadronic decay.Comment: 17 page
Mixing and the Decay
We reexamine the decay, adding the
effect of mixing to the amplitude calculated with the aid of
chiral perturbation theory and vector meson dominance. We predict the neutral
decay to occur with a width of \omega \to \pi^{0} \pi^{0} \gamma and also analyze the effect of the mixing
on the \omega \to \pi^{0} \pi^{0} \gamma \omega \to
\pi^{+} \pi^{-} \gamma ratio. Several remarks on the effect of
mixing on certain radiative decays of vector mesons are
presented.Comment: 10 pages, LaTeX, 1 ps-figure. Submitted to Phys. Rev.
Field-linked States of Ultracold Polar Molecules
We explore the character of a novel set of ``field-linked'' states that were
predicted in [A. V. Avdeenkov and J. L. Bohn, Phys. Rev. Lett. 90, 043006
(2003)]. These states exist at ultralow temperatures in the presence of an
electrostatic field, and their properties are strongly dependent on the field's
strength. We clarify the nature of these quasi-bound states by constructing
their wave functions and determining their approximate quantum numbers. As the
properties of field-linked states are strongly defined by anisotropic dipolar
and Stark interactions, we construct adiabatic surfaces as functions of both
the intermolecular distance and the angle that the intermolecular axis makes
with the electric field. Within an adiabatic approximation we solve the 2-D
Schrodinger equation to find bound states, whose energies correlate well with
resonance features found in fully-converged multichannel scattering
calculations
Translating the patient perception of integrated care survey to measure integrated care in The Netherlands : Combining equivalence and contextualization approaches for optimal results
Introduction: An increase in initiatives to improve integration of care provides the need for instruments that assess the degree of integrated care as perceived by patients across cultural contexts. This article aims to explain the relevance of equivalence and contextualization approaches in translating and adapting the Patient Perception of Integrated Care Survey developed in the US for use in the Netherlands. Theory and methods: The World Health Organization guidelines guided the translation and adaptation, including a forward-backward translation and patient-feedback through informal contacts (N4) and cognitive interviews (N14). Results: The forward-backward translation produced a Dutch version of the Patient Perception of Integrated Care Survey with minor adaptations. Patients evaluated the survey as very relevant. Alterations resulted from structural and cultural differences and specificities of patients with chronic conditions. Conclusions and discussion: A context-sensitive translation process is key to developing instruments for cross-cultural health research. Our results show that equivalence- and contextualization methods provide equally relevant, yet substantially different contributions to the translation outcome and should both be incorporated when translating instruments for different cultural contexts. The results support the applicability of the Patient Perception of Integrated Care Survey in the Netherlands and are promising for its adoption in other cultural contexts
Banking union in historical perspective: the initiative of the European Commission in the 1960s-1970s
This article shows that planning for the organization of EU banking regulation and supervision did not just appear on the agenda in recent years with discussions over the creation of the eurozone banking union. It unveils a hitherto neglected initiative of the European Commission in the 1960s and early 1970s. Drawing on extensive archival work, this article explains that this initiative, however, rested on a number of different assumptions, and emerged in a much different context. It first explains that the Commission's initial project was not crisis-driven; that it articulated the link between monetary integration and banking regulation; and finally that it did not set out to move the supervisory framework to the supranational level, unlike present-day developments
Can organisational culture of teams be a lever for integrating care? An exploratory study
Introduction: Organisational culture is believed to be an important facilitator for better integrated care, yet how organisational culture impacts integrated care remains underspecified. In an exploratory study, we assessed the relationship between organisational culture in primary care centres as perceived by primary care teams and patient-perceived levels of integrated care. Theory and methods: We analysed a sample of 2,911 patient responses and 17 healthcare teams in four primary care centres. We used three-level ordered logistic regression models to account for the nesting of patients within health care teams within primary care centres. Results: Our results suggest a non-linear relationship between organisational culture at the team level and integrated care. A combination of different culture typesâincluding moderate levels of production-oriented, hierarchical and team-oriented cultures and low or high levels of adhocracy culturesârelated to higher patient-perceived levels of integrated care. Conclusions and discussion: Organisational culture at the level of healthcare teams has significant associations with patient-perceived integrated care. Our results may be valuable for primary care organisations in their efforts to compose healthcare teams that are predisposed to providing better integrated care
Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control
This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York
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