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Quantum electrodynamics (QED), the quantum field theory that describes the interaction between light and matter, is commonly regarded as the best-tested quantum theory in modern physics. However, this claim is mostly based on extremely precise studies performed in the domain of relatively low field strengths and light atoms and ions1–6. In the realm of very strong electromagnetic fields such as in the heaviest highly charged ions (with nuclear charge Z≫ 1), QED calculations enter a qualitatively different, non-perturbative regime. Yet, the corresponding experimental studies are very challenging, and theoretical predictions are only partially tested. Here we present an experiment sensitive to higher-order QED effects and electron–electron interactions in the high-Zregime. This is achieved by using a multi-reference method based on Doppler-tuned X-ray emission from stored relativistic uranium ions with different charge states. The energy of the 1s1/22p3/2J= 2 → 1s1/22s1/2J= 1 intrashell transition in the heaviest two-electron ion (U90+) is obtained with an accuracy of 37 ppm. Furthermore, a comparison of uranium ions with different numbers of bound electrons enables us to disentangle and to test separately the one-electron higher-order QED effects and the bound electron–electron interaction terms without the uncertainty related to the nuclear radius. Moreover, our experimental result can discriminate between several state-of-the-art theoretical approaches and provides an important benchmark for calculations in the strong-field domain.

Interoperability is considered one of the main obstacles to the fully adoption of Industry4.0. Reference Architectures, like RAMI4.0, considering normal operation and maintenance of industrial equipment, paved the way to break that interoperability barrier and OPC-UA, in this context, is the reference communication protocol. This paper explores findings when performing a performance comparative study between OPC-UA and MQTT in an industrial application. The results shows that a lighter protocol brings advantages to direct applications when the data needs to be delivered fast and without a specific focus on the data structure.

ABSTRACT The presence of cracks debilitates the structural performance of rammed earth. Grout injection is a repair solution put forward recently, where compatibility issues demand using mud grouts. Little is [...]

In this article, we address the delay-dependent robust stability of uncertain fractional order neutral-type (FONT) systems with distributed delays, nonlinear perturbations, and input saturation. With the aid of the Lyapunov–Krasovskii functional, criteria on asymptotic robust stability of FONT, expressed in terms of linear matrix inequalities, are constructed to compute the state-feedback controller gains. The controller gains are determined subject to maximizing the domain of attraction via the cone complementarity linearization algorithm. The theoretical results are validated using numerical simulations.

This paper analyses several features of fundamental and composite particles using a computational approach. Different distances are used to unravel the connections among particles emerging from their characteristics. Two clustering and visualization techniques are adopted, namely hierarchical clustering (HC) and multidimensional scaling (MDS), for comparing the particles’ attributes and portraying the results in a smaller number of dimensions. In the first phase, 31 fundamental particles are assessed under the light of 6 characteristics. The Canberra and Lorentzian distances adapt well to the data set producing graphical representations consistent with the present-day knowledge. In the second phase, 88 composite particles including 21 tetraquark and 7 pentaquark candidates, described by 10 characteristics, are considered. The different cases are represented and visualized using maps created by the HC and MDS techniques. The MDS exhibits superior performance for representing the pentaquark states. Additionally, the two computational tools are tested when representing (1) normalized numerical real-valued data, and (2) categorical data. The MDS reveals that the categories’ strategy captures better the main characteristics of the data set. The numerical measures allow assessing a few unmeasured spin-parity quantum numbers JPfor 5 tetraquark candidates, namely the X(4020), X(4050), X(4055), X(4100), and X(4250). Therefore, algorithmic modeling proves to be a powerful tool for exploring numerical data sets with complex information.

ABSTRACT The paper presents a new semi-destructive method for obtaining a prediction of the tension parallel to the grain properties of clear wood of structural timber members. This method is [...]

The cable equation is one useful description for modeling phenomena such as neuronal dynamics and electrophysiology. The time-fractional cable model (TFCM) generalizes the classical cable equation by considering the anomalous diffusion that occurs in the ionic motion present for example in the neuronal system. This paper proposes a novel meshless numerical procedure, the radial basis function-generated finite difference (RBF-FD), to approximate the TFCM involving two fractional temporal derivatives. The time discretization of the TFCM is performed based on the Grünwald–Letnikov expansion. The spatial derivatives are discretized using the RBF-FD. The pattern of data distribution in the support domain is assumed as having a fixed number of points. The RBF-FD is based on the local support domain that leads to a sparsity system and also tackles the ill-conditioning problem caused by global collocation method. The theoretical stability and the convergence analysis of the scheme are also discussed in detail. It is shown that the proposed method is efficient and that the numerical results confirm the theoretical formulation.

This paper introduces a general class of nonlinear system of fractional partial differential equations with initial and boundary conditions. A hybrid method based on the transcendental Bernstein series and the generalized shifted Chebyshev polynomials is proposed for finding the optimal solution of the nonlinear system of fractional partial differential equations. The solution of the nonlinear system of fractional partial differential equations is expanded in terms of the transcendental Bernstein series and the generalized shifted Chebyshev polynomials, as basis functions with unknown free coefficients and control parameters. The corresponding operational matrices of fractional derivatives are then derived for the basis functions. These basis functions, with their operational matrices of fractional order derivatives and the Lagrange multipliers, transform the problem into a nonlinear system of algebraic equations. By means of Darbo’s fixed point theorem and Banach contraction principle, an existence result and a unique result for the solution of the nonlinear system of fractional partial differential equations are obtained, respectively. The convergence analysis is discussed and several illustrative experiments illustrate the efficiency and accuracy of the proposed method.

This paper presents an accurate localized meshfree collocation technique for the approximate solution of the second-order two-dimensional telegraph model. This model is an useful description of the propagation of electrical signals in a transmission line as well as wave phenomena. The proposed algorithm approximates the unknown solution in two steps. First, the discretization of time variable is accomplished by the Crank–Nicolson finite difference. Additionally, the unconditional stability and the convergence of the temporal semi-discretization approach are analysed with the help of the energy method in an appropriate Sobolev space. Second, the discretization of the spatial variable and its partial derivatives is obtained by the localized radial basis function partition of unity collocation method. The global collocation methods pose a considerable computational burden due to the calculation of the dense algebraic system. With the proposed approach, the domain is decomposed into several subdomains via a kernel approximation on every local domain. Therefore, it is possible to make the algebraic system more sparse and, consequently, to achieve a small condition number and a limited computational cost. Three numerical examples support the theoretical study and highlight the effectiveness of the method.

This paper proposes a conceptual experiment embedding the model of a bouncing ball and the Grünwald-Letnikov (GL) formulation for derivative of fractional order. The impacts of the ball with the surface are modeled by means of a restitution coefficient related to the coefficients of the GL fractional derivative. The results are straightforward to interpret under the light of the classical physics. The mechanical experiment leads to a physical perspective and allows a straightforward visualization. This strategy provides not only a motivational introduction to students of the fractional calculus, but also triggers possible discussion with regard to the use of fractional models in mechanics.

In this editorial paper, we start by surveying of the main milestones in the organization, foundation, and development of the journal Fractional Calculus and Applied Analysis(FCAA). The main potential of FCAAis in its readers, authors, and editors who contribute to the scientific advance and promote the progress of the journal. Among the editors, a special role of the honorary editors who contributed significantly to the foundation of the journal should be highlighted. These are prominent scientists, lecturers, and disseminators of FC and related topics. Unfortunately, some of them have already passed away, but they remain our living and lasting memory. In the main part of this survey, we remind the readers some biographical data and achievements related to FCAAtopics of these Honorary Founding Editors: Professors Eric Love, Ian Sneddon, Bogoljub Stanković, Rudolf Gorenflo, Danuta Przeworska-Rolewicz, Gary Roach, Anatoly Kilbas, and Wen Chen. In eight sections, each devoted to one of the honorary editors, their ways in science and in FC, as well as their main results and publications are shortly described. Special attention is given to their role in foundation of FCAAand to their contributions to its success story.

This paper introduces the notion of “fractional fractals”. The main idea is to establish a connection between the classical iterated function system and the first order truncation of the Grndwald-Letnikov fractional derivative. This allows us to consider higher order truncations, and also to study the limit sets for these higher order systems. We prove several results involving the existence and dimension of such limit sets, that will be called “fractional fractals”. Some numerical calculations and representations illustrate relevant examples.

This manuscript develops a numerical approach for approximating the solution of the fractional Riccati differential equation (FRDE): Dμu(x)+a(x)u2(x)+b(x)u(x)=g(x),0≤μ≤1,0≤x≤t,u(0)=d,$$\begin{align*}D^{\mu}&u(x)+a(x) u^2(x)+b(x) u(x)= g(x),\quad 0\leq \mu \leq 1,\quad 0\leq x \leq t,\\&u(0)=d,\end{align*}$$

There is an increasing interest in the field of functional and fractional differential equations. The lack of closed-form analytical solutions motivates the development of numerical methods for solving mixed-type fractional-order functional differential equations (MFFDEs) with retarded and neutral terms. This paper studies the solution of MFFDEs by a collocation technique with modified Lucas polynomials. The proposed method uses operational matrices to obtain an approximate solution by means of a system of linear algebraic equations. The accuracy of the proposed algorithm is verified with three illustrative examples.

La douleur, et plus particulièrement la douleur chronique, est un enjeu majeur de santé publique. Parmi les syndromes douloureux, la fibromyalgie se situe au cœur des préoccupations et pose de grandes difficultés, tant de diagnostic que de prise en charge. Aujourd’hui encore, de nombreux patients se font prescrire des traitements qui ne les soulagent que trop peu, soulevant l’intérêt d’une prise en charge non-médicamenteuse.

The ability of the so-called Caputo-Fabrizio (CF) and Atangana-Baleanu (AB) operators to create suitable models for real data is tested with real world data. Two alternative models based on the CF and AB operators are assessed and compared with known models for data sets obtained from electrochemical capacitors and the human body electrical impedance. The results show that the CF and AB descriptions perform poorly when compared with the classical fractional derivatives.

This paper analyses the citation profiles (CP) of 130 researchers in fractional calculus. In a first phase, the Canberra distance is used to measure the similarities between the researchers’ CP, and the multidimensional scaling technique (MDS) is adopted for processing and visualizing the information. In a second phase, the gamma probability distribution is used to fit the normalized CP and the gamma parameters are used to characterize the researchers. The MDS results and the gamma distribution parameters are represented graphically in 2- and 3-dimensional locus depicting the relative positions of the researchers.

Highlights • Generalisation of Cornu spirals in the perspective of fractional calculus. • Calculation of fractional Cornu spirals. • Use of symbolic packages in fractional calculus. Abstract This paper introduces two fractional integral sine and cosine curves. Based on such formulation a series of fractional plane and space Cornu spirals are represented. These curves can be used for modeling diffraction phenomena under the light of the fractional calculus tools. The adoption of symbolic packages simplifies the model implementation showing that present-day computational resources lead to a straightforward implementation of fractional differential equations. [ABSTRACT FROM AUTHOR]

This paper proposes an cost-efficient method for the numerical solution of fractional differential equations of multi-order. The suggested algorithm adopts the operational matrix of fractional derivative in term of Caputo sense using modified cubic B-spline functions. The new method leads to a system of algebraic equations that improves the solution accuracy and reduces the computational complexity. Several numerical examples illustrate the applicability of the proposed method.

Discussions under this title were held during a round table in frames of the International Conference “Fractional Differentiation and Its Applications” (ICFDA’18) held in 16-18 July 2018, Amman, The Hashemite Kingdom of Jordan, see details at http://conferences.ju.edu.jo/en/icfda2018/Home.aspx.

This paper proposes a new strategy to study some useful properties of growth rates of functions in C α ∈ R spaces in order to analyze the Leibniz rule for fractional derivatives. The differential operators are taken in the Riemann–Liouville sense. Moreover, stability analysis of the proposed strategy is investigated. The results demonstrate that the proposed theoretical analysis is accurate. [ABSTRACT FROM AUTHOR]

This paper investigates the numerical approximation of the tempered fractional integral by using the Sinc-collocation scheme. The algorithm is extended to solve a class of tempered fractional differential equations that converges to the solution with exponential rate. Several numerical examples compare the numerical approximations with the exact solutions. The behavioral responses of the lumped capacitance model with tempered fractional order for transient conduction are investigated. The efficiency and accuracy of the proposed scheme are analyzed in the perspective of the $$L_2$$ L2 -norm error and convergence order

This short note analyses the Caputo–Fabrizio operator. It is verified that it does not fit the usual concepts neither for fractional nor for integer derivative/integral. [ABSTRACT FROM AUTHOR]

Si la violence au travail n’est pas un phénomène nouveau, sa reconnaissance et sa prise en charge sont bien plus récentes. Les conséquences sur les salariés, en particulier lors de menaces avec armes, peuvent être très graves (sentiment de culpabilité, d’abandon de l’entourage, perte de confiance en soi, altération de l’identité…) et viennent justifier de l’importance de penser sa prise en charge. Le débriefing psychologique apparaît être, au regard de la littérature scientifique, une piste de choix.

Background: Case report, in a patient with a history of diabetes and hypertension, treated with metformin, gliclazide, enalapril + hydrochlorothiazide, amlodipine, aspirin and diazepam, recently medicated for a gouty crisis with colchicine and clonixin without improvement. Believing it could help in the treatment of gouty crisis symptoms he took about 1.5 L of artichoke infusion (Cynara cardunculus). He felt better and did agriculture work but developed a distal muscle pain, severe anemia, standard biochemical liver cholestasis, increase of alkaline phosphatase and marked increase of inflammatory parameters (hyperleucocytosis) and enters in the emergency department at the hospital. Objective: Evaluation of the cause of complaints and laboratory abnormalities and the involvement of artichoke infusion. Results: The prominence of the inflammatory parameters was ruled out because of exhaustive autoimmune, infectious or para-neoplastic syndrome (blood cultures, serology, diagnostic imaging, bone marrow and bone biopsy, muscle biopsy and nerve, abdominal angiography) were carried out showing normal results. The evaluation pointed out that the concomitant intake of artichoke infusion may have been involved in the framework developed, since the drugs which were being administered to/by the patient have a metabolism mainly mediated by CYP450 3A4 and 2C9 that could be compromised when these isoenzymes are inhibited by phenolic and flavonoid compounds from plants. Colchicine was one of the last drugs took that have as side effects most of the symptoms felt by patient including diarrhea and anemia. Conclusion: The spontaneous and complete recovery of the patient and the negativity of research looking for other causes, conduce to a strong possibility of the interaction between artichoke and the drugs in the clinical presentation of this case.

A new generation of aircraft with distributed propellers leads to operational performances superior to those exhibited by standard designs. Computational simulations and experimental tests show a reduction of fuel consumption and noise. This paper proposes an analogy between aerodynamics and electrical circuits. The model reveals properties similar to those of fractional-order systems and gives a deeper insight into the dynamics of multi-propeller coupling. [ABSTRACT FROM AUTHOR]

A non-differentiable model of the LC-electric circuit described by a local fractional differential equation of fractal dimensional order is addressed in this article. From the fractal electrodynamics point of view, the relaxation oscillator, defined on Cantor sets in LC-electric circuit, and its exact solution using the local fractional Laplace transform are obtained. Comparative results among local fractional derivative, Riemann–Liouville fractional derivative and conventional derivative are discussed. Local fractional calculus is proposed as a new tool suitable for the study of a large class of electric circuits. [ABSTRACT FROM AUTHOR]

Since the 60s of last century Fractional Calculus exhibited a remarkable progress and presently it is recognized to be an important topic in the scientific arena. This survey analyzes and measures the evolution that occurred during the last five decades in the light of books, journals and conferences dedicated to the theory and applications of this mathematical tool, dealing with operations of integration and differentiation of arbitrary (fractional) order and their generalizations.

This paper studies the periodic functions in the perspective of fractional calculus application. It is shown that the fractional derivative of a periodic signal is periodic if it is defined on the whole real line. Several common fractional derivative formulations are considered, namely the Grünwald–Letnikov, Liouville and Caputo on $$\mathbb {R}$$ R , and the two-sided fractional derivatives. It is verified that the fractional derivative of a causal periodic signal is never causal periodic. The periodic behaviour of the fractional linear systems is also studied. If such systems are defined with suitable derivatives the output corresponding to periodic input is also periodic. Is is concluded that only the integer order linear systems can have a sinusoidal impulse response.

The development of models constitutes a fundamental step in the study of natural and artificial systems. Present day science aims to address broader and more complex areas of application requiring, therefore, new concepts and models. This paper explores the concept of generalized two-port network by embedding the ideas of fractional calculus, memristor, transformer and gyrator. Each element represents separately one possible direction for generalizing the classical elements, but the cross-fertilization of the distinct topics has been overlooked. In this line of thought, the proposal of a novel element is a logical conjecture for obeying the symmetries that have been discovered in nature. [ABSTRACT FROM AUTHOR]

This paper explores the use of multidimensional scaling for analyzing the dynamics of the N -link planar pendulum. Several integer- and fractional-order pendular systems are studied based on the time response and energy of the links. The dynamics get increasingly complex and chaotic with the number of degrees-of-freedom. The numerical experiments demonstrate the feasibility of the proposed methodology in analyzing the data and motivate its extension for other performance measures and dynamical systems. [ABSTRACT FROM AUTHOR]

Atmospheric temperatures characterize Earth as a slow dynamics spatiotemporal system, revealing long-memory and complex behavior. Temperature time series of 54 worldwide geographic locations are considered as representative of the Earth weather dynamics. These data are then interpreted as the time evolution of a set of state space variables describing a complex system. The data are analyzed by means of multidimensional scaling (MDS), and the fractional state space portrait (fSSP). A centennial perspective covering the period from 1910 to 2012 allows MDS to identify similarities among different Earth’s locations. The multivariate mutual information is proposed to determine the “optimal” order of the time derivative for the fSSP representation. The fSSP emerges as a valuable alternative for visualizing system dynamics.

Discussions under this title were held during a special session in frames of the International Conference “Fractional Differentiation and Applications” (ICFDA’ 14) held in Catania (Italy), 23-25 June 2014, see details at http://www.icfda14.dieei.unict.it/. Along with the presentations made during this session, we include here some contributions by the participants sent afterwards and also by few colleagues planning but failed to attend.

In this paper we study several natural and man-made complex phenomena in the perspective of dynamical systems. For each class of phenomena, the system outputs are time-series records obtained in identical conditions. The time-series are viewed as manifestations of the system behavior and are processed for analyzing the system dynamics. First, we use the Fourier transform to process the data and we approximate the amplitude spectra by means of power law functions. We interpret the power law parameters as a phenomenological signature of the system dynamics. Second, we adopt the techniques of non-hierarchical clustering and multidimensional scaling to visualize hidden relationships between the complex phenomena. Third, we propose a vector field based analogy to interpret the patterns unveiled by the PL parameters.

Gottfried Leibniz generalized the derivation and integration, extending the operators from integer up to real, or even complex, orders. It is presently recognized that the resulting models capture long term memory effects difficult to describe by classical tools. Leon Chua generalized the set of lumped electrical elements that provide the building blocks in mathematical models. His proposal of the memristor and of higher order elements broadened the scope of variables and relationships embedded in the development of models. This paper follows the two directions and proposes a new logical step, by generalizing the concept of junction. Classical junctions interconnect system elements using simple algebraic restrictions. Nevertheless, this simplistic approach may be misleading in the presence of unexpected dynamical phenomena and requires including additional "parasitic" elements. The novel γ-junction includes, as special cases, the standard series and parallel connections and allows a new degree of freedom when building models. The proposal motivates the search for experimental and real world manifestations of the abstract conjectures. [ABSTRACT FROM AUTHOR]

Positron annihilation lifetime (LS) and Doppler broadening annihilation radiation lineshape (DBARL) were measured at room temperature in a series of solid acetylacetonate chelates involving metals of different groups. The LS and DBARL obtained parameters were associated with the electronic configuration of the central metal ions and their electronic spectra.

Positron annihilation lifetime (LS) and Doppler broadening annihilation radiation lineshape (DBARL) spectroscopies measurements were performed in several binary solid solutions of the general formula M(1-x)G(x)L3where M = Al (III), Ga (III), or In (III), as matrix ; G = Cr (III), Mn (III), Fe (III), Co (III), Ru (III), Rh (III), and Ir (III), as guest molecules, L = acetylacetone (acac) or dipivaloylmethane (dpm), and X = guest molecule mole fraction. The studied systems can be classified in two groups : the first one presenting only inhibition of positronium formation and the second one presenting inhibition and quenching effects. The inhibition and quenching constants were determined.

This paper studies several topics related with the concept of “fractional” that are not directly related with Fractional Calculus, but can help the reader in pursuit new research directions. We introduce the concept of non-integer positional number systems, fractional sums, fractional powers of a square matrix, tolerant computing and FracSets, negative probabilities, fractional delay discrete-time linear systems, and fractional Fourier transform.

Highlights: [•] Analysis of initial conditions from the viewpoint of numerical approximations. [•] Statistical study of the impact of initial conditions in fractional systems. [•] Numerical benchmark of initialization in fractional dynamics. [Copyright &y& Elsevier]

This paper proposes a quantitative approach to specify potentially hazardous asteroids using clustering tools to group a set of near-Earth asteroids (NEAs). The data pool adopted in the study contains a number of distinct indices characterizing ∼25,000NEAs. The hierarchical clustering (HC) and multidimensional scaling (MDS) algorithmic techniques are adopted for generating two- and three-dimensional graphical representations reflecting the main features of the NEAs. These techniques provide useful computational visualization tools for extracting information embedded in data sets having multidimensional nature. The structure of the loci, given by the emerging clusters and patterns, leads to a deeper understanding of the problem. The HC and MDS rely on the selection of adequate metrics for comparing the objects in the data set. Therefore, a pool of prototype distances are tested and a number of numerical experiments reveal that the Clark distance characterizes more assertively the NEA data set. The overlapped clusters and the pattern of a curved polyhedron that emerge in the MDS charts reveal that some PHAs may be overlooked with standard classifications of NEAs based merely on some scalar index, such as the case of the perihelion distance q<1.3AU. Furthermore, it is observed that the MDS is superior in performance to the HC since it takes advantage of three-dimensional representations. In fact, three-dimensional plots require iterative operations of rotation, shifting and magnification for achieving an efficient visualization, but such procedures are straightforward with present day computational resources. This strategy allows the adoption of advanced scientific data processing and visualization techniques that lead to ‘maps’ close to our understanding of the NEA impact risk.

This paper presents a survey of useful, established formulas in Fractional Calculus, systematically collected for reference purposes.

This paper studies the Fermi-Pasta-Ulam problem having in mind the generalization provided by Fractional Calculus (FC). The study starts by addressing the classical formulation, based on the standard integer order differential calculus and evaluates the time and frequency responses. A first generalization to be investigated consists in the direct replacement of the springs by fractional elements of the dissipative type. It is observed that the responses settle rapidly and no relevant phenomena occur. A second approach consists of replacing the springs by a blend of energy extracting and energy inserting elements of symmetrical fractional order with amplitude modulated by quadratic terms. The numerical results reveal a response close to chaotic behaviour.

Fractional dynamics reveals long range memory properties of systems described by means of signals represented by real numbers. Alternatively, dynamical systems and signals can adopt a representation where states are quantified using a set of symbols. Such signals occur both in nature and in man made processes and have the potential of a aftermath as relevant as the classical counterpart. This paper explores the association of Fractional calculus and symbolic dynamics. The results are visualized by means of the multidimensional technique and reveal the association between the fractal dimension and one definition of fractional derivative.

During the last fifty years the area of Fractional Calculus verified a considerable progress. This paper analyzes and measures the evolution that occurred since 1966.

Abstract: Fractional calculus generalizes integer order derivatives and integrals. Memristor systems generalize the notion of electrical elements. Both concepts were shown to model important classes of phenomena. This paper goes a step further by embedding both tools in a generalization considering complex-order objects. Two complex operators leading to real-valued results are proposed. The proposed class of models generate a broad universe of elements. Several combinations of values are tested and the corresponding dynamical behavior is analyzed. [Copyright &y& Elsevier]

IntroductionC-reactive protein (CRP) levels rise during inflammatory processes and have been ordered for rheumatic disease follow-up since the 1950s. The number of tests ordered in the emergency setting has increased, but without evident improvement in medical care quality.ObjectiveTo determine the pattern of CRP determinations in the emergency department (ED) of a university hospital in Sao Paulo, Brazil, and to evaluate the effect of an intervention with staff and students about the best use of the test in the ED.MethodsData regarding CRP testing requests, related diagnoses and the number of monthly consultations in the hospital ED were analysed before and after the intervention. Because of an increase in CRP measurement requests from 2007 to 2009, the author started discussing the role of CRP determinations in the medical decision-making process in early 2010. Staff and faculty members openly discussed the pattern of requests in the hospital and related current medical literature. During 2010, the medical staff worked as multipliers to change the behaviour of new students and residents. The results of the first 4 months after the intervention were presented at another general meeting in July 2010.ResultsFrom 2007 to 2009, there were 11 786 CRP measurement requests with a clear exponential trend. After the intervention, during the calendar year 2010, there was a 48% reduction in adjusted annual CRP requests. Pneumonia, fever and urinary tract infections were the most common reasons for CRP requests.DiscussionInexpensive, well-directed, interactive educational interventions may affect professional behaviour and curb rates of laboratory tests.