Isotope effect in impure high T_c superconductors

The influence of various kinds of impurities on the isotope shift exponent \alpha of high temperature superconductors has been studied. In these materials the dopant impurities, like Sr in La_{2-x}Sr_xCuO_4, play different role and usually occupy different sites than impurities like Zn, Fe, Ni {\it etc} intentionally introduced into the system to study its superconducting properties. In the paper the in-plane and out-of-plane impurities present in layered superconductors have been considered. They differently affect the superconducting transition temperature T_c. The relative change of isotope shift coefficient, however, is an universal function of T_c/T_{c0} (T_{c0} reffers to impurity free system) {\it i.e.} for angle independent scattering rate and density of states function it does not depend whether the change of T_c is due to in- or out-of-plane impurities. The role of the anisotropic impurity scattering in changing oxygen isotope coefficient of superconductors with various symmetries of the order parameter is elucidated. The comparison of the calculated and experimental dependence of \alpha/\alpha_0, where \alpha_0 is the clean system isotope shift coefficient, on T_c/T_{c0} is presented for a number of cases studied. The changes of \alpha calculated within stripe model of superconductivity in copper oxides resonably well describe the data on La_{1.8}Sr_{0.2}Cu_{1-x}(Fe,Ni)_xO_4, without any fitting parameters.Comment: 8 pages, 6 figures, Phys. Rev. B67 (2003) accepte

Measurements, Models, Systems and Design

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Does the Community-based Combined Meeting Center Support Programme (MCSP) Make the Pathway to Day-care Activities Easier for People Living with Dementia? A Comparison Before and After Implementation of MCSP in Three European Countries

The "pathway to care" concept offers a helpful framework for preparing national dementia plans and strategies and provides a structure to explore the availability and accessibility of timely and effective care for people with dementia and support for their informal carers. Within the framework of the JPND-MEETINGDEM implementation project the pathways to regular day-care activities and the Meeting Centers Support Programme (MCSP), an innovative combined support form for people with dementia and carers, was explored. An exploratory, descriptive, qualitative, cross-country design was applied to investigate the pathways to day care in several regions in four European countries (Italy, Poland, United Kingdom, and the Netherlands). Before implementation of MCSP, of the four countries the United Kingdom had the most structured pathway to post-diagnostic support for people with dementia. MCSP introduction had a positive impact on the pathways to day-care activities in all countries. MCSP filled an important gap in post-diagnostic care, increasing the accessibility to support for both people with dementia and carers. Key elements such as program of activities, target group, and collaboration between healthcare and social services were recognized as success factors. This study shows that MCSP fills (part of) the gap between diagnosis and residential care and can therefore be seen as a pillar of post-diagnostic care and support. Further dissemination of Meeting Centers in Europe may have a multiple impact on the structure of dementia services in European countries and the pathways to day care for people with dementia and their carer(s)

Evidence-based nanoscopic and molecular framework for excipient functionality in compressed orally disintegrating tablets

The work investigates the adhesive/cohesive molecular and physical interactions together with nanoscopic features of commonly used orally disintegrating tablet (ODT) excipients microcrystalline cellulose (MCC) and D-mannitol. This helps to elucidate the underlying physico-chemical and mechanical mechanisms responsible for powder densification and optimum product functionality. Atomic force microscopy (AFM) contact mode analysis was performed to measure nano-adhesion forces and surface energies between excipient-drug particles (6-10 different particles per each pair). Moreover, surface topography images (100 nm2-10 μm2) and roughness data were acquired from AFM tapping mode. AFM data were related to ODT macro/microscopic properties obtained from SEM, FTIR, XRD, thermal analysis using DSC and TGA, disintegration testing, Heckel and tabletability profiles. The study results showed a good association between the adhesive molecular and physical forces of paired particles and the resultant densification mechanisms responsible for mechanical strength of tablets. MCC micro roughness was 3 times that of D-mannitol which explains the high hardness of MCC ODTs due to mechanical interlocking. Hydrogen bonding between MCC particles could not be established from both AFM and FTIR solid state investigation. On the contrary, D-mannitol produced fragile ODTs due to fragmentation of surface crystallites during compression attained from its weak crystal structure. Furthermore, AFM analysis has shown the presence of extensive micro fibril structures inhabiting nano pores which further supports the use of MCC as a disintegrant. Overall, excipients (and model drugs) showed mechanistic behaviour on the nano/micro scale that could be related to the functionality of materials on the macro scale. © 2014 Al-khattawi et al

SAT-based bounded model checking for timed interpreted systems and the RTECTLK properties

We define an SAT-based bounded model checking (BMC) method for RTECTLK (the existential fragment of the real-time computation tree logic with knowledge) that is interpreted over timed models generated by timed interpreted systems. Specifically, we translate the model checking problem for RTECTLK to the model checking problem for a variant of branching temporal logic (called EyCTLK) interpreted over an abstract model, and we redefine an SAT-based BMC technique for EyCTLK

On the SMT-based verification of communicative commitments

We propose an SMT-based bounded model checking (BMC) technique for the existential fragments of CCTL*K – an epistemic temporal logic extended to include modalities for different social commitments – and for multi-agent systems modelled by Communication Interpreted Systems (CIS). Furthermore, we exemplify the use of the technique by means of the NetBill protocol, a popular example in the MAS literature related to the modelling of business processes

SAT-based searching for k-quasi-optimal runs in weighted timed automata

In the paper we are concerned with an optimal cost reachability problem for weighted timed automata, and we use a translation to SAT to solve the problem. In particular, we show how to find a run of length k ∈ IN that starts at the initial state and terminates at a state containing a target location, its total cost belongs to the interval [c,c+1), for some natural number c ∈ IN, and the cost of each other run of length k, which also leads from the initial state to a state containing the target location, is greater or equal to c. This kind of runs is called k-quasi-optimal. We exemplify the use of our solution to the mentioned problem by means of the air traffic control problem, and we provide some preliminary experimental results