655 research outputs found
Isotope effect in total muon capture rates on nuclei and isotensor effective potential
Isotope effects are considered in the framework of the energy-weighted sum rule treatment of muon capture on nuclei. The possibility of exploiting total capture rates to convey information on nuclear structure is pointed out
Development of a hybrid FE-SEA-experimental model
The vibro-acoustic response of complex structures with uncertain properties is a problem of great concern for modern industries. In recent years, much research has been devoted to the prediction of this response
in the mid-frequency range where, because neither Finite element analysis nor statistical energy analysis are appropriate, a hybrid deterministic-statistical approach becomes a suitable solution. Despite its potential,
the existence of systems with active components that are too complex to be modelled numerically can limit the application of the method. However, it may still be possible to measure the dynamical response of these
structures experimentally. This paper is hence concerned with the possibility of integrating experimental data into a hybrid deterministic-statistical method. To explain the new methodology, two similar case
studies, consisting of a deterministic source structure that is coupled to a statistical plate receiver using passive isolators, are used. For each case, the vibratory excitation, characterised using in-situ blocked
force measurements, the source structure mobility, and the isolators stiffness are experimentally determined and inserted in the proposed hybrid model of the system. The paper explains the techniques used for
obtaining the considered experimental data and the theoretical model proposed for describing the systems. To validate the proposed approach, the predicted vibration response of the receiver plate is compared to the
one obtained by experimentally randomising the plate in both case studies. The results show that a good agreement is obtained, both for the ensemble average response of the receiver structure and for the ensemble variance of this response. Moreover, the upper con dence bounds predicted by the hybrid method enclose well the ensemble of experimental results. The cause of some narrow-band differences observed between the predicted response and the experimental measurements is finally discussed. It is therefore concluded
that the capabilities of the hybrid deterministic-statistical method can be clearly enhanced through the incorporation of experimental data prescribing active sub-systems
Plataformes digitals per aprendre activa i cooperativament
e-status es una plataforma web que propone ejercicios a los estudiantes que se
corrigen automĂĄticamente. Un mismo ejercicio puede repetirse todas las veces
que se desea, puesto que los datos son diferentes cada vez. Al acabar de
resolver el ejercicio el estudiante obtiene una realimentaciĂłn de su trabajo. La
plataforma se ha utilizado en los Ășltimos cursos en asignaturas de estadĂstica
de distintas carreras y presenta varias ventajas: fomenta el aprendizaje
autĂłnomo, permite adaptarse a los diferentes ritmos de aprendizaje y libera al
profesor de la tarea rutinaria de la correcciĂłn. La plataforma supone un
refuerzo prĂĄctico para el aprendizaje en disciplinas basadas en aplicaciĂłn de
técnicas cuantitativas y estudio de casos.
Para evaluar la influencia y efectividad del uso de la herramienta en el
resultado de la evaluaciĂłn, se ha realizado un estudio con los estudiantes
matriculados en el segundo cuatrimestre del curso 2007-2008 de la asignatura
âMĂ©todos estadĂsticos de la ingenierĂa Iâ, una asignatura troncal de la carrera
de ingenierĂa industrial con 210 alumnos.Peer Reviewe
An experimental exploration of the properties of random frequency response functions
The vibro-acoustic analysis of complex structures over a broadband frequency range is an extremely challenging problem that may often require the use of a hybrid deterministic-statistical approach. Due to manufacturing imperfections, the frequency response functions (FRFs) of an ensemble of nominally identical systems can be considered to be random. These FRFs, however, have statistical properties that can be potentially used in vibro-acoustic models. This work explores some of these fundamental properties by using measured FRFs from an ensemble of nominally identical structures, obtained by randomising a thin rectangular plate using point masses. It is first shown that the measured ensemble of FRFs satisfies the analyticity-ergodicity condition, experimentally verifying this recently demonstrated fundamental property. Then, the ensemble is used to explore whether the direct field dynamic stiffness, a key parameter in a well-established hybrid deterministic-statistical formulation, can be obtained experimentally. The results are compared against those computed using numerical techniques, showing that measured data may be a suitable alternative provided that an ensemble of systems can be measured. Finally, an alternative method, based on the use of virtual point masses, opposed to physical ones, is proposed for those cases where experimental randomisation is particularly challenging. It has been found, however, that the method may be extremely sensitive to measurement imprecisions, specially when applied to lightly damped structures. It is concluded that the statistical properties of random causal FRFs are not only interesting in themselves, but can enhance and extend vibro-acoustic prediction models
Meson-induced correlations of nucleons in nuclear Compton scattering
The non-resonant (seagull) contribution to the nuclear Compton amplitude at
low energies is strongly influenced by nucleon correlations arising from meson
exchange. We study this problem in a modified Fermi gas model, where nuclear
correlation functions are obtained with the help of perturbation theory. The
dependence of the mesonic seagull amplitude on the nuclear radius is
investigated and the influence of a realistic nuclear density on this amplitude
is dicussed. We found that different form factors appear for the static part
(proportional to the enhancement constant ) of the mesonic seagull
amplitude and for the parts, which contain the contribution from
electromagnetic polarizabilities.Comment: 15 pages, Latex, epsf.sty, 9 eps figures
A phase I pharmacokinetic and safety study of cabazitaxel in adult cancer patients with normal and impaired renal function
Limited data are available on cabazitaxel pharmacokinetics in patients with renal impairment. This open-label, multicenter study assessed cabazitaxel in patients with advanced solid tumors and normal or impaired renal function.
Cohorts A (normal renal function: creatinine clearance [CrCL]Â >80Â mL/min/1.73Â m), B (moderate renal impairment: CrCL 30 to <50Â mL/min/1.73Â m) and C (severe impairment: CrCLÂ <30Â mL/min/1.73Â m(2)) received cabazitaxel 25Â mg/m (A, B) or 20Â mg/m(2) (C, could be escalated to 25Â mg/m), once every 3Â weeks. Pharmacokinetic parameters and cabazitaxel unbound fraction (F) were assessed using linear regression and mixed models. Geometric mean (GM) and GM ratios (GMRs) were determined using mean CrCL intervals (moderate and severe renal impairment: 40 and 15Â mL/min/1.73Â m) versus a control (90Â mL/min/1.73Â m).
Overall, 25 patients received cabazitaxel (median cycles: 3 [range 1-20]; Cohort A: 5 [2-13]; Cohort B: 3 [1-15]; and Cohort C: 5 [1-20]), of which 24 were eligible for pharmacokinetic analysis (eight in each cohort). For moderate and severe renal impairment versus normal renal function, GMR estimates were: clearance normalized to body surface area (CL/BSA) 0.95 (90% CI 0.80-1.13) and 0.89 (0.61-1.32); area under the curve normalized to dose (AUC/dose) 1.06 (0.88-1.27) and 1.14 (0.76-1.71); and F U 0.99 (0.94-1.04) and 0.97 (0.87-1.09), respectively. Estimated slopes of linear regression of log parameters versus log CrCL (renal impairment) were: CL/BSA 0.06 (-0.15 to 0.28); AUC/dose -0.07 (-0.30 to 0.16); and F U 0.02 (-0.05 to 0.08). Cabazitaxel safety profile was consistent with previous reports.
Renal impairment had no clinically meaningful effect on cabazitaxel pharmacokinetics.This study was supported by Sanofi. Javier Garcia-Corbacho acknowledges clinical fellowship support from SEOM. Experimental Cancer Medicine Centre (ECMC) and NIHR Biomedical Research Centre (BRC) funding is also acknowledged for the Cambridge Cancer Centre
Articulating practice through the interview to the double
The paper aims to realise the critical potential of the practice lens by contributing to the
development of a coherent set of methodologies for investigating work and
organisational activity. It does so by introducing and critically assessing the "interview
to the double" as a method to articulate and represent practice.
After briefly illustrating its history and usage, the paper analyses in depth the setting
generated by this unusual interview method. It argues that the nature of the encounter
produces narratives that are often morally connoted and idealised in character. As a
consequence the method is especially useful to capture the going concerns which orient
the conduct of the members and the normative and moral dimension of practice. The
paper also shows that because it mimics familiar instruction-giving discursive practices,
the method constitutes an effective textual device to convey this moral and normative
dimension in a way which remains faithful to its situated and contingent nature of
practice
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