A new weighting scheme and discriminative approach for information retrieval in static and dynamic document collections

This paper introduces a new weighting scheme in information retrieval. It also proposes using the document centroid as a threshold for normalizing documents in a document collection. Document centroid normalization helps to achieve more effective information retrieval as it enables good discrimination between documents. In the context of a machine learning application, namely unsupervised document indexing and retrieval, we compared the effectiveness of the proposed weighting scheme to the 'Term Frequency - Inverse Document Frequency' or TF-IDF, which is commonly used and considered as one of the best existing weighting schemes. The paper shows how the document centroid is used to remove less significant weights from documents and how this helps to achieve better retrieval effectiveness. Most of the existing weighting schemes in information retrieval research assume that the whole document collection is static. The results presented in this paper show that the proposed weighting scheme can produce higher retrieval effectiveness compared with the TF-IDF weighting scheme, in both static and dynamic document collections. The results also show the variation in information retrieval effectiveness that is achieved for static and dynamic document collections by using a specific weighting scheme. This type of comparison has not been presented in the literature before

Conceptual modelling of the flow of frail elderly through acute-care hospitals: An evidence-based management approach

This is the author accepted manuscript. The final version is available from Emerald via the DOI in this record.The ageing of the world’s population is causing an increase in the number of frail patients admitted to hospitals. In the absence of appropriate management and organisation, these patients risk an excessive length of stay and poor outcomes. To deal with this problem, we propose a conceptual model to facilitate the pathway of frail elderly patients across acute-care hospitals, focused on avoiding improper wait times and treatment during the process. The conceptual model is developed to enrich the standard flowchart of a clinical pathway in the hospital. The modified flowchart encompasses new organisational units and activities carried out by new dedicated professional roles. The proposed variant aims to provide a correct assessment of frailty at the entrance, a better management of the patient’s stay during different clinical stages and an early discharge, sending the patient home or to other facilities, avoiding a delayed discharge. The model is completed by a set of indicators aimed at measuring performance improvements and creating a strong database of evidence on the managing of frail elderly’s pathways, providing proper information that can validate the model when applied in current practice. The paper proposes a design of the clinical path of frail patients in acute-care hospitals, combining elements that, according to an evidence-based management approach, have proved to be effective in terms of outcomes, costs and organisational issues. We can therefore expect an improvement in the treatment of frail patients in hospital, avoiding their functional decline and worsening frailty conditions, as often happens in current practice following the standard path of other patients The framework proposed is a conceptual model to manage frail elderly patients in acute-care wards. Our research approach lacks application to real data and proof of effectiveness. Further work will be devoted to implementing a simulation model for a specific case study and verifying the impact of the conceptual model in real care settings. The framework proposed is a conceptual model to manage frail elderly patients in acute-care wards. Our research approach lacks application to real data and proof of effectiveness. Further work will be devoted to implementing a simulation model for a specific case study and verifying the impact of the conceptual model in real care settings. This paper fulfills an identified need to study and provide solutions for the management of frail elderly patients in acute-care hospitals, and generally to produce value in a patient-centred model

Nonlinear dynamics of coupled transverse-rotational waves in granular chains

The nonlinear dynamics of coupled waves in one-dimensional granular chains with and without a substrate is theoretically studied accounting for quadratic nonlinearity. The multiple time scale method is used to derive the nonlinear dispersion relations for infinite granular chains and to obtain the wave solutions for semiinfinite systems. It is shown that the sum-frequency and difference-frequency components of the coupled transverse-rotational waves are generated due to their nonlinear interactions with the longitudinal wave. Nonlinear resonances are not present in the chain with no substrate where these frequency components have low amplitudes and exhibit beating oscillations. In the chain positioned on a substrate two types of nonlinear resonances are predicted. At resonance, the fundamental frequency wave amplitudes decrease and the generated frequency component amplitudes increase along the chain, accompanied by the oscillations due to the wave numbers asynchronism. The results confirm the possibility of a highly efficient energy transfer between the waves of different frequencies, which could find applications in the design of acoustic devices for energy transfer and energy rectification

Quantum coherence of discrete kink solitons in ion traps

We propose to realize quantized discrete kinks with cold trapped ions. We show that long-lived solitonlike configurations are manifested as deformations of the zigzag structure in the linear Paul trap, and are topologically protected in a circular trap with an odd number of ions. We study the quantum-mechanical time evolution of a high-frequency, gap separated internal mode of a static kink and find long coherence times when the system is cooled to the Doppler limit. The spectral properties of the internal modes make them ideally suited for manipulation using current technology. This suggests that ion traps can be used to test quantum-mechanical effects with solitons and explore ideas for the utilization of the solitonic internal-modes as carriers of quantum information.Comment: 5 pages, 4 figures ; minor correction

Modes of Oscillation in Radiofrequency Paul Traps

We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem of stable trapping of general three-dimensional crystals is considered and the validity of the pseudopotential approximation is discussed. We derive analytically the micromotion amplitude of the ions, rigorously proving well-known experimental observations. We use a method of infinite determinants to find the modes which diagonalize the linearized time-dependent dynamical problem. This allows obtaining explicitly the ('Floquet-Lyapunov') transformation to coordinates of decoupled linear oscillators. We demonstrate the utility of the method by analyzing the modes of a small `peculiar' crystal in a linear Paul trap. The calculations can be readily generalized to multispecies ion crystals in general multipole traps, and time-dependent quantum wavefunctions of ion oscillations in such traps can be obtained.Comment: 24 pages, 3 figures, v2 adds citations and small correction

Detachment of linking film bacteria from enamel surfaces by oral rinses and penetration of sodium lauryl sulphate through an artificial oral biofilm.

The biofilm mode of growth protects plaque micro-organisms against environmental attacks, such as from antimicrobials or detergents. Dental plaque is linked to enamel through the adhesion of initial colonizers. Once this link is disrupted, the entire plaque mass adhering to it detaches. Experiments in a parallel-plate flow chamber demonstrated that bacteria adhering to saliva-coated enamel could not be stimulated to detach by perfusion of the flow chamber with two traditional mouthrinses (Corsodyl and Scope), whereas perfusion with a prebrushing rinse (Plax) or its detergent components stimulated detachment from saliva-coated enamel of a wide variety of bacterial strains. Following perfusion of the flow chamber with the mouthrinses, little additional detachment of adhering bacteria by the passage of a liquid-air interface occurred. After perfusion with the prebrushing rinse, however, significant numbers of still-adhering bacteria could be stimulated to detach by passage of a liquid-air interface, indicating that Plax had weakened their adhesive bond. The ability of Plax or its detergent components to detach plaque bacteria is not always obvious from in vivo experiments, and reports on its clinical efficacy are inconsistent. Likely, antimicrobials or detergents are unable to penetrate the plaque and reach the linking film bacteria, as demonstrated here by Fourier transform infrared spectroscopy.</p

Precise Experimental Investigation of Eigenmodes in a Planar Ion Crystal

The accurate characterization of eigenmodes and eigenfrequencies of two-dimensional ion crystals provides the foundation for the use of such structures for quantum simulation purposes. We present a combined experimental and theoretical study of two-dimensional ion crystals. We demonstrate that standard pseudopotential theory accurately predicts the positions of the ions and the location of structural transitions between different crystal configurations. However, pseudopotential theory is insufficient to determine eigenfrequencies of the two-dimensional ion crystals accurately but shows significant deviations from the experimental data obtained from resolved sideband spectroscopy. Agreement at the level of 2.5 x 10^(-3) is found with the full time-dependent Coulomb theory using the Floquet-Lyapunov approach and the effect is understood from the dynamics of two-dimensional ion crystals in the Paul trap. The results represent initial steps towards an exploitation of these structures for quantum simulation schemes.Comment: 5 pages, 4 figures, supplemental material (mathematica and matlab files) available upon reques

New contributions to the geographical distinction of painted andalusi plinths

[EN] Few examples remain of artistic Andalusi decoration in the form of painted plinths in residential settings. Several technological issues have arisen when noting potential connections in an attempt to contextualize the styles, geography and chronologies of these plinths. Using XRD, FTIR and stratigraphic analysis, and considering previous research, the study of execution techniques and materials observed in plinths in Baŷŷāna (Almería) has made it possible to establish parallels with decorated plinths from the Barrio de casas de la Alcazaba in Malaga. Based on these results, interesting conclusions can be drawn regarding production techniques which are in keeping with the survival of certain execution procedures of Roman origin for renderings. Furthermore, the existence of a production nucleus grouping the examples from Almería and Malaga is proposed within a technical context which would set them apart.[ES] Una manifestación artística de la decoración andalusí de la que se conservan escasos testimonios son los zócalos pintados en el ámbito doméstico. Los intentos por contextualizar estilística, geográfica y cronológicamente estos zócalos han planteado algunas cuestiones de índole tecnológica a la hora de apuntar posibles conexiones. El estudio de las técnicas de ejecución y materiales empleados en zócalos de Baŷŷāna (Almería), mediante análisis estratigráfico, DRX y FTIR, ha permitido establecer paralelismos con zócalos decorados procedentes del barrio de casas de la Alcazaba de Málaga a partir de una investigación anterior. Los resultados permiten extraer interesantes conclusiones sobre las técnicas de elaboración, que son congruentes con la pervivencia de algunos procedimientos de ejecución de los enlucidos de raigambre romana. Además, se plantea aquí la existencia de un núcleo de producción que agruparía los ejemplos provenientes de Almería y Málaga, cuyo contexto técnico los diferenciaría.Alejandre Sánchez, FJ.; Núñez Guerrero, C.; Díaz Ramos, S.; Pérez-Malumbres Landa, A. (2023). Nuevas aportaciones a la diferenciación geográfica de los zócalos pintados andalusíes. Loggia, Arquitectura & Restauración. (36):40-51. https://doi.org/10.4995/loggia.2023.1996940513

Two Scenarios of Breaking Chaotic Phase Synchronization

Two types of phase synchronization (accordingly, two scenarios of breaking phase synchronization) between coupled stochastic oscillators are shown to exist depending on the discrepancy between the control parameters of interacting oscillators, as in the case of classical synchronization of periodic oscillators. If interacting stochastic oscillators are weakly detuned, the phase coherency of the attractors persists when phase synchronization breaks. Conversely, if the control parameters differ considerably, the chaotic attractor becomes phase-incoherent under the conditions of phase synchronization break.Comment: 8 pages, 7 figure