On the Number of Balanced Words of Given Length and Height over a Two-Letter Alphabet

We exhibit a recurrence on the number of discrete line segments joining two integer points in the plane using an encoding of such segments as balanced words of given length and height over the two-letter alphabet $\{0,1\}$. We give generating functions and study the asymptotic behaviour. As a particular case, we focus on the symmetrical discrete segments which are encoded by balanced palindromes.Comment: 24 page

Cost of illness due to pertussis in adults ≥50 years of age in the United Kingdom

Background: Pertussis is an endemic respiratory tract infection caused by Bordetella pertussis that may affect all individuals from infants to older adults. Pertussis incidence in adults is often underreported and in various countries, including the United Kingdom (UK), there are evidence gaps on pertussis-associated economic burden in the older adult population. We aimed to quantify the economic burden of pertussis in adults aged ≥50 years in the UK. Methods: A cost-of-illness study was conducted to estimate the cost of pertussis from a societal perspective. We utilized a sum diagnosis cost approach in which costs related to infection with pertussis were included. Medical, patient, and indirect costs were calculated individually and combined to calculate total costs. A framework was developed to assess costs for consecutive age groups from 50–54 years of age to ≥85 years of age. Sensitivity and scenario analyses were used to assess analysis uncertainty. Results: The base-case analysis estimated the total annual economic burden of pertussis to be approximately £238 million (M). This comprised approximately £159 M in indirect costs, £66 M in medical costs, and £13 M in patient costs. Costs for the age group 55–59 years had the highest impact on the economic burden, with approximately £79 M in total annual costs. Visits to general practitioners and nurses were the largest contributors to medical costs (∼£37 M) followed by inpatient visits (∼£21 M). Transportation costs (∼£10 M) were the major patient costs. Productivity loss (∼£71 M) and leisure time loss (∼£72 M) had comparable contributions to annual indirect costs. Sensitivity and scenario analyses suggested that incidence rates, indirect costs, and underreporting estimates had the highest impact on outcomes. Conclusion: Total cost of pertussis in the UK among adults ≥50 years of age is substantial and highest for adults 55–59 years of age. Indirect costs were the main contributors to the economic burden.</p

From Acceptability to Acceptance: Does Experience with the Product Influence User Initial Representations?

International audienceAdopting a product can be seen as a process that implies some repeated use influencing either positively or negatively judgment over time. Indeed, product judgement is likely to evolve over time and influence the intention to continue using. At yet, little research is avalaible on the evolution of product jugdgement with use. In this paper, we examined the evolution of User eXperience (UX) and affective-motivational factors between evaluation before and after use. Results showed that interaction with the product significantly influences initial representations with, in our study, more negative judgments after use. Moreover, using Expectation-Disconfirmation Theory, significant influences of initial evaluations (i.e. judgement before use) and disconfirmation (i.e. difference between judgement after and before use) were found on behavioral intention after use

Head-to-head domain walls in one-dimensional nanostructures: an extended phase diagram ranging from strips to cylindrical wires

International audienceSo far magnetic domain walls in one-dimensional structures have been described theoretically only in the cases of flat strips, or cylindrical structures with a compact cross-section, either square or disk. Here we describe an extended phase diagram unifying the two pictures, extensively covering the (width,thickness) space. It is derived on the basis of symmetry and phase-transition arguments, and micromagnetic simulations. A simple classification of all domain walls in two varieties is proposed on the basis of their topology: either with a combined transverse/vortex character, or of the Bloch-point type. The exact arrangement of magnetization within each variety results mostly from the need to decrease dipolar energy, giving rise to asymmetric and curling structures. Numerical evaluators are introduced to quantify curling, and scaling laws are derived analytically for some of the iso-energy lines of the phase diagram

Modélisation interfaciale de chocs dans les suspensions

International audienceL'onde de choc faible dans une suspension diluée et la zone de relaxation amont sont considérées comme des milieux interfaciaux. Les transferts de quantité de mouvement et d'énergie sont analysés par la thermodynamique des processus irréversibles. La singularité au voisinage du régime sonique est étudiée au moyen de développements asymptotiques. Le raccordement peut être opéré avec une théorie linéarisée des interfaces. Abstract: The weak shock wave in a dilute suspension and the downstream relaxation zone are considered as examples of interfaces in multiphase flows. Thermodynamics of Irreversible Processes is used to analyze momentum and energy transfers between phases. The singularity near the sonic regime is studied by means of asymptotic expansions. Matching can be performed with a linearized theory of interfaces. Mots clés : écoulement polyphasique, interface, suspension, onde de choc, développement asymptotiqu

MODELISATION INTERFACIALE DE CHOCS DANS LES SUSPENSIONS

International audienceL'onde de choc faible dans une suspension diluée et la zone de relaxation amont sont considérées comme des milieux interfaciaux. Les transferts de quantité de mouvement et d'énergie sont analysés par la thermodynamique des processus irréversibles. La singularité au voisinage du régime sonique est étudiée au moyen de développements asymptotiques. Le raccordement peut être opéré avec une théorie linéarisée des interfaces. Abstract: The weak shock wave in a dilute suspension and the downstream relaxation zone are considered as examples of interfaces in multiphase flows. Thermodynamics of Irreversible Processes is used to analyze momentum and energy transfers between phases. The singularity near the sonic regime is studied by means of asymptotic expansions. Matching can be performed with a linearized theory of interfaces. Mots clés : écoulement polyphasique, interface, suspension, onde de choc, développement asymptotiqu

Observation of Bloch-point domain walls in cylindrical magnetic nanowires

Topological protection is an elegant way of warranting the integrity of quantum and nanosized systems. In magnetism one example is the Bloch-point, a peculiar object implying the local vanishing of magnetization within a ferromagnet. Its existence had been postulated and described theoretically since several decades, however it has never been observed. We con rm experimentally the existence of Bloch points, imaged within domain walls in cylindrical magnetic nanowires, combining surface and transmission XMCD-PEEM magnetic microscopy. This opens the way to the experimental search for peculiar phenomena predicted during the motion of Bloch-point-based domain walls

On the Number of Balanced Words of Given Length and Height over a Two-Letter Alphabet

We exhibit a recurrence on the number of discrete line segments joining two integer points in the plane using an encoding of such segments as balanced words of given length and height over the two-letter alphabet $\{0,1\}$. We give generating functions and study the asymptotic behaviour. As a particular case, we focus on the symmetrical discrete segments which are encoded by balanced palindromes

Extensive degeneracy, Coulomb phase and magnetic monopoles in an artificial realization of the square ice model

Artificial spin ice systems have been introduced as a possible mean to investigate frustration effects in a well-controlled manner by fabricating lithographically-patterned two-dimensional arrangements of interacting magnetic nanostructures. This approach offers the opportunity to visualize unconventional states of matter, directly in real space, and triggered a wealth of studies at the frontier between nanomagnetism, statistical thermodynamics and condensed matter physics. Despite the strong efforts made these last ten years to provide an artificial realization of the celebrated square ice model, no simple geometry based on arrays of nanomagnets succeeded to capture the macroscopically degenerate ground state manifold of the corresponding model. Instead, in all works reported so far, square lattices of nanomagnets are characterized by a magnetically ordered ground state consisting of local flux-closure configurations with alternating chirality. Here, we show experimentally and theoretically, that all the characteristics of the square ice model can be observed if the artificial square lattice is properly designed. The spin configurations we image after demagnetizing our arrays reveal unambiguous signatures of an algebraic spin liquid state characterized by the presence of pinch points in the associated magnetic structure factor. Local excitations, i.e. classical analogues of magnetic monopoles, are found to be free to evolve in a massively degenerated, divergence-free vacuum. We thus provide the first lab-on-chip platform allowing the investigation of collective phenomena, including Coulomb phases and ice-like physics.Comment: 26 pages, 10 figure

Community-Level Responses to Iron Availability in Open Ocean Plankton Ecosystems

Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio-oceanographic and bio-omics data sets from Tara Oceans in the context of the iron products from two state-of-the-art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large-scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment