819 research outputs found
Communicative competence and psychological aspects when interacting with client in tourism
The article deals with the role of psychological preparation of specialists in service and tourism to building relationships with clients of travel agencies. Attention is paid to what is important in psychological preparation of the expert assigned to the speech skill, because the possession of speech skills influences the formation of the motives and interests of the client, speed, completeness and the strength of assimilation of advertising materials, economy, recall; accuracy, consistency and brightness of managerial playback of the advertised materia
SYNTHESIS AND APPLICATION OF CROWN ETHERS
Mono- and bis-benzo-15-crown-5-ether derivatives have been synthesized and determined
their potentiometric K+ selectivity factors. Of bis-crown ether urethanes highly selective Iigands
were found some of which was used as active ingredient in potassium selective membrane
electrode.
Sugar based crown ethers, aza-crowns and cryptands were also prepared and applied as
chiral catalyst in enantioselective reactions
The effects of manufacturing tolerances and assembly force on the volumetric wear at the taper junction in modular total hip arthroplasty
Item does not contain fulltextFretting and corrosion at the taper-head interface in total hip arthroplasty has been reported as a potential cause of early failure of the implant system. The finite element (FE) method can be used to study the mechanics at the taper junction that are difficult to assess experimentally. Taper mismatch is one of the factors that can influence the performance of the taper junction. In this study we have assessed the effect of taper mismatch, in combination with assembly force on the volumetric wear. The study showed that higher assembly forces and smaller mismatches result in the least volumetric wear
Rapid Development of Medical Imaging Tools with Open-Source Libraries
Rapid prototyping is an important element in researching new imaging analysis techniques and developing custom medical applications. In the last ten years, the open source community and the number of open source libraries and freely available frameworks for biomedical research have grown significantly. What they offer are now considered standards in medical image analysis, computer-aided diagnosis, and medical visualization. A cursory review of the peer-reviewed literature in imaging informatics (indeed, in almost any information technology-dependent scientific discipline) indicates the current reliance on open source libraries to accelerate development and validation of processes and techniques. In this survey paper, we review and compare a few of the most successful open source libraries and frameworks for medical application development. Our dual intentions are to provide evidence that these approaches already constitute a vital and essential part of medical image analysis, diagnosis, and visualization and to motivate the reader to use open source libraries and software for rapid prototyping of medical applications and tools
The Quantum Adiabatic Approximation and the Geometric Phase
A precise definition of an adiabaticity parameter of a time-dependent
Hamiltonian is proposed. A variation of the time-dependent perturbation theory
is presented which yields a series expansion of the evolution operator
with being at least of
the order . In particular corresponds to the
adiabatic approximation and yields Berry's adiabatic phase. It is shown that
this series expansion has nothing to do with the -expansion of
. It is also shown that the non-adiabatic part of the evolution
operator is generated by a transformed Hamiltonian which is off-diagonal in the
eigenbasis of the initial Hamiltonian. Some related issues concerning the
geometric phase are also discussed.Comment: uuencoded LaTeX file, 19 page
Estimating time-to-onset of adverse drug reactions from spontaneous reporting databases.
International audienceBACKGROUND: Analyzing time-to-onset of adverse drug reactions from treatment exposure contributes to meeting pharmacovigilance objectives, i.e. identification and prevention. Post-marketing data are available from reporting systems. Times-to-onset from such databases are right-truncated because some patients who were exposed to the drug and who will eventually develop the adverse drug reaction may do it after the time of analysis and thus are not included in the data. Acknowledgment of the developments adapted to right-truncated data is not widespread and these methods have never been used in pharmacovigilance. We assess the use of appropriate methods as well as the consequences of not taking right truncation into account (naïve approach) on parametric maximum likelihood estimation of time-to-onset distribution. METHODS: Both approaches, naïve or taking right truncation into account, were compared with a simulation study. We used twelve scenarios for the exponential distribution and twenty-four for the Weibull and log-logistic distributions. These scenarios are defined by a set of parameters: the parameters of the time-to-onset distribution, the probability of this distribution falling within an observable values interval and the sample size. An application to reported lymphoma after anti TNF-¿ treatment from the French pharmacovigilance is presented. RESULTS: The simulation study shows that the bias and the mean squared error might in some instances be unacceptably large when right truncation is not considered while the truncation-based estimator shows always better and often satisfactory performances and the gap may be large. For the real dataset, the estimated expected time-to-onset leads to a minimum difference of 58 weeks between both approaches, which is not negligible. This difference is obtained for the Weibull model, under which the estimated probability of this distribution falling within an observable values interval is not far from 1. CONCLUSIONS: It is necessary to take right truncation into account for estimating time-to-onset of adverse drug reactions from spontaneous reporting databases
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