Conservative-variable average states for equilibrium gas multi-dimensional fluxes

Modern split component evaluations of the flux vector Jacobians are thoroughly analyzed for equilibrium-gas average-state determinations. It is shown that all such derivations satisfy a fundamental eigenvalue consistency theorem. A conservative-variable average state is then developed for arbitrary equilibrium-gas equations of state and curvilinear-coordinate fluxes. Original expressions for eigenvalues, sound speed, Mach number, and eigenvectors are then determined for a general average Jacobian, and it is shown that the average eigenvalues, Mach number, and eigenvectors may not coincide with their classical pointwise counterparts. A general equilibrium-gas equation of state is then discussed for conservative-variable computational fluid dynamics (CFD) Euler formulations. The associated derivations lead to unique compatibility relations that constrain the pressure Jacobian derivatives. Thereafter, alternative forms for the pressure variation and average sound speed are developed in terms of two average pressure Jacobian derivatives. Significantly, no additional degree of freedom exists in the determination of these two average partial derivatives of pressure. Therefore, they are simultaneously computed exactly without any auxiliary relation, hence without any geometric solution projection or arbitrary scale factors. Several alternative formulations are then compared and key differences highlighted with emphasis on the determination of the pressure variation and average sound speed. The relevant underlying assumptions are identified, including some subtle approximations that are inherently employed in published average-state procedures. Finally, a representative test case is discussed for which an intrinsically exact average state is determined. This exact state is then compared with the predictions of recent methods, and their inherent approximations are appropriately quantified

Muscoloskeletal disorders and occupational stress of violinists

Although musculoskeletal disorders are the most frequent cause of occupational diseases in musicians, very few studies have focused attention on a single category of instruments, in particular on the violin. This involves, in its practice, almost all the areas of the body, besides being in the category of strings which is the most numerous in an orchestra. A specific protocol, investigating postural and clinical profiles of the muskoloskeletal apparatus as well as job stress, was utilized in a conservatory on graduates in the tenth year of violin study, who regularly participated in activities of orchestras or string quartets. The investigation revealed “target segments” of osteoarticular apparatus (jaw, vertebral spine, shoulders, elbows, hands and fingers, lower limbs) electively subjected to overuse, as well as muscle contracture of trapezoids and hyperkeratosis of fingers and clavicle. Although the work environment was comfortable, most violinists claimed to undergo intense rhythms and competitiveness. This study, highlighting sublinical occupational diseases in young musicians (violinists) suggests adequate prevention measures

Kinetic theory of age-structured stochastic birth-death processes

Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but are unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Stochastic theories that treat semi-Markov age-dependent processes using, e.g., the Bellman-Harris equation do not resolve a population's age structure and are unable to quantify population-size dependencies. Conversely, current theories that include size-dependent population dynamics (e.g., mathematical models that include carrying capacity such as the logistic equation) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new, fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a Bogoliubov-–Born–-Green–-Kirkwood-–Yvon-like hierarchy. Explicit solutions are derived in three limits: no birth, no death, and steady state. These are then compared with their corresponding mean-field results. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution

An arbitrary grid CFD algorithm for configuration aerodynamics analysis. Volume 1: Theory and validations

This report documents the user input and output data requirements for the FEMNAS finite element Navier-Stokes code for real-gas simulations of external aerodynamics flowfields. This code was developed for the configuration aerodynamics branch of NASA ARC, under SBIR Phase 2 contract NAS2-124568 by Computational Mechanics Corporation (COMCO). This report is in two volumes. Volume 1 contains the theory for the derived finite element algorithm and describes the test cases used to validate the computer program described in the Volume 2 user guide

Demographic parameters of two populations of red coral (Corallium rubrum L. 1758) in the North Western Mediterranean

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Bioactivators as a potential strategy for dredged marine sediment recovery

Sediment dredging from harbors and water bodies in order to maintain the navigation is a necessity worldwide; however, the storage and treatment of sediments is a problem for harbor managers. Sediment decontamination could represent a sustainable approach for turning them into a new source of environmentally reusable material. To manage the sediments dredged from the Livorno harbour, several possible recycling techniques are being explored, including sediment washing and bioremediation. A combination of these two techniques can also be taken into consideration. This study examines the feasibility of an enzyme enhanced bioremediation technology used as it is, or in combination with the sediment washing. Specifically, we applied an enhanced bioremediation approach to both raw sediments and two derivate granulometric fractions separated by a pilot sediment washing facility: a silt-clay fraction (63 \u3bcm<200 \u3bcm). The preliminary sediment washing was effective in concentrating the organic and inorganic contamination into a smaller volume of fine sediment particles (silt-clay). The bioremediation experiment, carried out in triplicate at mesoscale level, consisted in setting up containers of about 0.2 m3 each, filled with the three matrices (raw sediment, clay-silt and sand fractions) treated and untreated (control) with bioactivators (a mixture of microorganisms, enzymes and synergists). The physical, chemical and biological properties of sediments were determined at the initial sampling time (t0) and after three months (t90) from the beginning of the experimentation. The bioactivator application, providing specialized microorganisms and stimulating the growth of indigenous microorganisms, determined the increase in microbial respiration and in hydrolytic enzyme activities in all the treated matrices, in particular in the siltclay fraction. However, this fraction both treated and untreated, has not been able to degrade significant amount of organic pollutants. This is probably due to the burial of contaminats in micropores making them inaccessible to microorganisms and extracellular enzymes. On the contrary, a significant reduction in total petroleum hydrocarbon was observed in sand and raw sediment matrices after three months from remediation strategy application (about 50%), indicating the efficiency of the bioremediation technology

Cardiac surgery practice during the COVID-19 outbreak: A regionwide survey

Background: Health systems worldwide have been overburdened by the "COVID-19 surge". Consequently, strategies to remodulate non-COVID medical and surgical care had to be developed. Knowledge of the impact of COVID surge on cardiac surgery practice is mainstem. Present study aims to evaluate the regional practice pattern during lockdown in Campania. Methods: A multicenter regional observational 26-question survey was conducted, including all adult cardiac surgery units in Campania, Italy, to assess how surgical practice has changed during COVID-19 national lockdown. Results: All centers adopted specific protocols for screening patients and personnel. A significant reduction in the number of dedicated intensive care unit (ICU) beds (-30.0%±38.1%, range: 0-100%) and cardiac operating rooms (-22.2%±26.4%, range: 0-50%) along with personnel relocation to other departments was disclosed (anesthesiologists -5.8%±11.1%, range: 0-33.3%; perfusionists -5.6%±16.7%, range: 0-50%; nurses -4.8%±13.2%, range: 0-40%; cardiologists -3.2%±9.5%, range: 0-28.6%). Cardiac surgeons were never reallocated to other services. Globally, we witnessed dramatically lower adult cardiac surgery case volumes (335 vs. 667 procedures, P&lt;0.001), as institutions and surgeons followed guidelines to curtail non-urgent operations. Conclusions: This regional survey demonstrates major changes in practice as a response to the COVID-19 pandemic. In this respect, this experience might lead to the development of permanent systems-based plans for future pandemic and may effectively help policy decision making when prioritizing healthcare resource reallocation during and after the pandemic

Experimental evidence of stochastic resonance without tuning due to non Gaussian noises

In order to test theoretical predictions, we have studied the phenomenon of stochastic resonance in an electronic experimental system driven by white non Gaussian noise. In agreement with the theoretical predictions our main findings are: an enhancement of the sensibility of the system together with a remarkable widening of the response (robustness). This implies that even a single resonant unit can reach a marked reduction in the need of noise tuning.Comment: 4 pages, 3 figure

A Spatially Resolved Dark- versus Light-Zone Microenvironment Signature Subdivides Germinal Center-Related Aggressive B Cell Lymphomas

We applied digital spatial profiling for 87 immune and stromal genes to lymph node germinal center (GC) dark- and light-zone (DZ/LZ) regions of interest to obtain a differential signature of these two distinct microenvironments. The spatially resolved 53-genes signature, comprising key genes of the DZ mutational machinery and LZ immune and mesenchymal milieu, was applied to the transcriptomes of 543 GC-related diffuse large B cell lymphomas and double-hit (DH) lymphomas. According to the DZ/LZ signature, the GC-related lymphomas were subclassified into two clusters. The subgroups differed in the distribution of DH cases and survival, with most DH displaying a distinct DZ-like profile. The clustering analysis was also performed using a 25-genes signature composed of genes positively enriched in the non-B, stromal sub-compartments, for the first time achieving DZ/LZ discrimination based on stromal/immune features. The report offers new insight into the GC microenvironment, hinting at a DZ microenvironment of origin in DH lymphomas