One of the challenges in the healthcare sector is making accurate forecasts across insurance years for claims reserve. Healthcare claims present huge variability and heterogeneity influenced by ...random decisions of the courts and intrinsic characteristics of the damaged parties, which makes traditional methods for estimating reserves inadequate. We propose a new methodology to estimate claim reserves in the healthcare insurance system based on generalized linear models using the Overdispersed Poisson distribution function. In this context, we developed a method to estimate the parameters of the quasi-likelihood function using a Gauss–Newton algorithm optimized through a genetic algorithm. The genetic algorithm plays a crucial role in glimpsing the position of the global minimum to ensure a correct convergence of the Gauss–Newton method, where the choice of the initial guess is fundamental. This methodology is applied as a case study to the healthcare system of the Tuscany region. The results were validated by comparing them with state-of-the-art measurement of the confidence intervals of the Overdispersed Poisson distribution parameters with better outcomes. Hence, local healthcare authorities could use the proposed and improved methodology to allocate resources dedicated to healthcare and global management.
Mechanical properties are very important when choosing a material for a specific application. They help to determine the range of usefulness of a material, establish the service life, and classify ...and identify materials. The size effect on mechanical properties has been well established numerically and experimentally. However, the role of the size effect combined with boundary and loading conditions on mechanical properties remains unknown. In this paper, by using molecular dynamics (MD) simulations with the state-of-the-art ReaxFF force field, we study mechanical properties of amorphous silica (e.g., Young's modulus, Poisson's ratio) as a function of domain size, full-/semi-periodic boundary condition, and tensile/compressive loading. We found that the domain-size effect on Young's modulus and Poisson's ratio is much more significant in semi-periodic domains compared to full-periodic domains. The results, for the first time, revealed the
and anisotropic nature of amorphous silica at the atomic level. We also defined a "safe zone" regarding the domain size, where the bulk properties of amorphous silica can be reproducible, while the computational cost and accuracy are in balance.
The paper proposes a hybrid 6 degrees of freedom localization system for endoscopic magnetic capsules, compatible with external high-grade permanent magnetic locomotion. The proposed localization ...system, which is able to provide an accurate estimation of the endoscopic capsule pose, finds application in the robotic endoscopy field to provide efficient closed-loop navigation of a magnetically-driven tethered capsule. It takes advantage of two optimization steps based on a triangulation approach, i.e. (1) mathematical approximations of the magnetic field, and (2) minimization of the magnetic field mean square deviation. The proposed localization system was tested in two different in-vitro scenarios for mimicking the clinical cases that a magnetic capsule would encounter during tele-operated magnetic navigation. The development phase was preceded by an in-depth work-space analysis to lay the groundwork for the localization design and implementation. Results of the hybrid 6 degrees of freedom localization system show a significant accuracy in accordance with the state-of-the-art, i.e. about 5 mm in position and 5° in orientation, but introducing benefits in expanding the work-space by increasing the number of electromagnets onto the operating table, as an independent solution with respect to the external magnetic locomotion source.
The knowledge of transport properties is crucial to design new devices in electronic and biotechnological industries. Due to the fast growth of the processor speed, molecular simulations have become ...a robust method to calculate the transport properties. In this work, we show numerical methods such as Green–Kubo formalism to estimate transport properties applied to real liquids. We focus on the study of shear viscosity and thermal conductivity of a water (H2O) and triethylamine (C6H15N) solution which has a potential application for heat exchange inside electronic circuits. The radial distribution function and hydrogen-bond analysis have been made at a broad range of temperatures and mole fractions using equilibrium molecular dynamics, and comparisons with experimental data in the literature have been reported.
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•ReaxFF molecular dynamics were used to study mechanical properties of amorphous silica.•Effect of porosity, pore shape and orientation was systematically investigated.•Impact of ...nanopore structures were universally characterized.•Mechanical properties can be controlled by nano-engineering pore structure.
Porous materials are typically heterogeneous and they contain large variations of micro-/nano-pore structures, causing complicated behaviors. In continuum models, most mechanical properties of porous materials are estimated based on porosity, while the variations of micro/nano structures are ignored. That could be problematic as the microscopic heterogeneity may affect the mechanical response of porous materials. Thus, understanding micro/nano heterogeneity impact has been the focus in many scientific and engineering subjects. In the present study, we investigated the effect of nanopore structure (including pore shape and orientation) as well as porosity on mechanical properties of amorphous silica (a-SiO2). The pore sizes in our simulations are comparable to the corresponding ones observed in a-SiO2 based materials. We found that the existing of nanopores strongly influences Young’s modulus (E) and critical energy release rate (GIC). These properties decrease with increasing porosity. Importantly, the impact of nanopores was characterized by structural parameters of porous materials. In addition to dependency on porosity, Young’s modulus also was found to vary as a function of potential energy per atom, which highly depends on nanopore shape. Furthermore, critical energy release rate was found to increase with increasing ligament length (also known as pore wall thickness). The results highlighted the importance of nanopore structures, which must be taken into account when studying fracture mechanisms in porous materials. Based on our findings, it was proposed that mechanical properties of porous materials can be controlled by nano-engineering pore structures.
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To improve decision-making strategies and prediction based on epidemiological data, so far biased by highly-variable criteria, algorithms using unbiased morbidity parameters, i.e. Intensive Care ...Units (ICU) and Ordinary Hospitalizations (OH), are proposed. ICU/OH acceleration and velocities are mathematically modeled using available and official data to derive two thresholds, alerting on 30<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> ICU and 40<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> OH of COVID-19 daily occupancy settled by the Italian Minister of Health, as a case of study. A predictive model is also proposed to estimate the daily occupancy of ICU and OH in hospitals for each region, using a Susceptible-Infected-Recovered-Death (SIRD) epidemic model to further extend occupancy prediction in each regional district. Computed data validated the proposed models in Italy after almost two years of pandemic, obtaining agreements with the Italian Presidential Decree regardless of the different regional trends of epidemic waves. Therefore, the decision-making algorithm and prediction model resulted valuable tools, retrospectively, to be tested prospectively in sustainable strategies to curb the impact of COVID-19, or of any other pandemic threats with any aggregate of data, on local healthcare systems.
A united atom force field for the homologous series of the poly(oxymethylene) dimethyl ethers (OMEn), H3C–O–(CH2O) n –CH3, is presented. OMEn are oxygenates and promising new synthetic fuels and ...solvents. The molecular geometry of the OMEn, the internal degrees of freedom, and their electrostatic properties were obtained from quantum mechanical calculations. To model repulsion and dispersion, Lennard-Jones parameters were fitted to the experimental liquid densities and vapor pressures of pure OMEn (n = 1–4). The critical properties of OMEn (n = 1–4) were determined from the simulation data. Additionally, the shear viscosity of pure liquid OMEn is evaluated and compared with literature data. Finally, the solubility of CO2 in OME2, OME3, and OME4 is predicted using a literature model for CO2 and the Lorentz–Berthelot combining rules. The results agree well with experimental data from the literature.
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The Griffith‐Ley oxidation of alcohols to aldehydes and ketones is performed with either RuCl3 ⋅ (H2O)x or a highly stable, well‐defined ruthenium catalyst and with cheap trimethylamine N‐oxide ...(TMAO) as the oxygen source. The use of n‐heptane as the solvent, which forms a second phase with TMAO and a part of the alcohol, allows the reactions to be performed with a minimum amount of catalyst. This results in high local concentrations and thus to very rapid conversions. Detailed quantum chemical calculations suggest, that the Griffith‐Ley oxidation not necessarily requires high oxidation states of ruthenium but can also proceed with RuII/RuIV species.
Ruthenium Catalysis: High yields and selectivities are achieved by using low‐valent ruthenium(II) catalysts for the oxidation of alcohols to carbonyl compounds. DFT calculations give an insight into a possible mechanism.
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Magnetically-driven robotic capsules have the potential to become the gold standard for colonoscopy, reducing patient pain while simplifying the overall procedure execution. The usage of a robotic ...arm to maneuver a permanent external magnet (EPM) for controlling the motion of a magnetic capsule within the gastrointestinal (GI) tract has been successfully demonstrated in pre-clinical scenarios. However, current control strategies struggle to navigate the capsule under realistic scenarios. In this work, the authors deduce a set of motion primitives for the EPM that optimize the navigation force provided to the capsule by reducing the contact force. Such motion primitives consider, for the first time, the resistance force introduced due to the contact between the endoscopic capsule and the GI tract. The results show that the proposed motion primitives enable the capsule to manage realistic scenarios, such as a 30 mm soft obstacle mimicking the compression of an organ, while a 10 mm obstacle would impede state-of-the-art strategies. In summary, the proposed control strategy improves the magnetically-driven endoscopic capsule navigation by optimizing the locomotion force and reducing by ~81% the contact force applied to the GI wall with a consequent reduction of the endoluminal stress.
In this work, we investigate immiscible fluid displacement at small scales where slip lengths are on the order of characteristic system sizes, whereby Cox's law is not expected to be valid. Molecular ...dynamics simulations show that in this limit hydrodynamic bending becomes small and interfaces remain approximately spherical. In this case the only relevant angle for describing the interface shape is the dynamic microscopic angle at the fluid-solid interface. In our simulations, this angle is found to be described well by the molecular-kinetic theory originally proposed by Blake and Haynes. In general, this implies a different functional dependence between the contact angle (and related quantities) and the flow speed (or capillary number); this is demonstrated for the case of the force on the boundary for immiscible fluid displacement in a two-dimensional channel.
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