Algebraic construction and numerical behaviour of a new s-consistent difference scheme for the 2D Navier-Stokes equations

In this paper we consider a regular grid with equal spatial spacings and construct a new finite difference approximation (difference scheme) for the system of two-dimensional Navier-Stokes equations describing the unsteady motion of an incompressible viscous liquid of constant viscosity. In so doing, we use earlier constructed discretization of the system of three equations: the continuity equation and the proper Navier-Stokes equations. Then, we compute the canonical Gröbner basis form for the obtained discrete system. It gives one more difference equation which is equivalent to the pressure Poisson equation modulo difference ideal generated by the Navier-Stokes equations, and thereby comprises a new finite difference approximation (scheme). We show that the new scheme is strongly consistent. Besides, our computational experiments demonstrate much better numerical behaviour of the new scheme in comparison with the other strongly consistent schemes we constructed earlier and also with the scheme which is not strongly consistent

Evaluation of the burden of HPV-related hospitalizations as a useful tool to increase awareness: 2007–2017 data from the sicilian hospital discharge records

In light of the implementation of human papillomavirus (HPV) prevention strategies, epidemiological studies in different geographical areas are required in order to assess the impact of HPV-related diseases. The purpose of the present study was to describe the burden of HPV-related hospitalizations in Sicily. A retrospective observational study estimated 43,531 hospitalizations attributable to HPV from 2007 to 2017. During the observed period, there was a decrease for all HPV-related conditions with a higher reduction, among neoplasms, for cervical cancer (annual percent change (APC) = −9.9%, p < 0.001). The median age for cervical cancer was 45 years old, with an increasing value from 43 to 47 years (p < 0.001). The age classes with greater decreases in hospital admissions for invasive cancers were women aged 35 years or more (APC range from −5.5 to −9.86) and 25–34 years old (APC = −11.87, p < 0.001) for women with cervical carcinoma in situ. After ten years for vaccine introduction and sixteen years for cervical cancer screening availability, a relatively large decrease in hospital admissions for cervical cancer and other HPV-related diseases in Sicily was observed. Some clinical characteristics of hospitalization, such as increasing age, are suggestive clues for the impact of preventive strategies, but further research is needed to confirm this relationship

Recent Decisions

Comments on recent decisions by William Fleming, Edward L. Burke, William J. Priebe, Anthony V. Amodio, Richard G. Dytrych, James Kalo, and John A. Pietrykowski

Polychlorinated biphenyls, organochlorine pesticides, and polycyclic aromatic hydrocarbons in wild, farmed, and frozen marine seafood marketed in Campania, Italy.

Polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were detected in fresh-catch, farmed, and frozen marine fish marketed in Campania, Italy. Additionally, polychlorobiphenyl congeners were found: six were non-dioxin-like (NDL-PCB) (IUPAC no. 28, 52, 101, 138, 153, and 180), and one was dioxin-like (DL-PCB) (IUPAC no. 118). In all, 93% of fresh-catch, 100% of aquaculture, and 74% of the frozen specimens contained PCBs at concentrations varying from 0.12 to 35.11 ng/g, wet weight; NDL-PCBs ranged between 0.12 and 32.44 ng/g. Penta-, hexa-, and heptachlorobiphenyls were predominant. Regarding organochlorine pesticides, hexachlorobenzene was detected in 35% of fresh catch, 36% of farmed, and 46% of the frozen fish specimens, in a range between < 0.01 and 3.29 ng/g. Contents of the dichlorodiphenyltrichloroethane isomer amounted to 0.12 to 11.00 ng/g. Finally, PAHs were detected in 100% of the specimens. Benzo[a]pyrene was detected in 66% of the aquaculture, 35% of the fresh catch, and 24% of the frozen species, at concentrations varying from 0.03 to 9.18 ng/g. On the basis of annual fish consumption, an average daily intake of NDL-PCBs of 6.02 ng/kg of body weight was estimated. Calculated daily hexachlorobenzene and total dichlorodiphenyltrichloroethane intakes were, respectively, 0.11 and 0.90 ng/kg of body weight per day. The contribution of fish to the daily consumption of the noncarcinogenic PAHs can be considered low; for benzo[a]pyrene, the estimated daily intake is considerably lower than the doses considered carcinogenic for experimental animals by the European Union Scientific Committee on Food

Recent Decisions

Comments on recent decisions by Thomas D. Logan, Bernard J. McGraw, Robert A. Stewart, Anthony V. Amodio, Frank A. Howard, Richard R. Murphy, Howard V. Burke, Robert D. Lightfoot, Robert A. Layden, James J. Haranzo, John M. Sullivan, and Robert C. Enburg

Design and preliminary test of a fluidised bed photoreactor for ethylene oxidation on mesoporous mixed SiO2/TiO2 nanocomposites under UV-A illumination

Ethylene (C2H4) is a plant hormone that has numerous effects on many horticultural and ornamental crops. It accelerates senescence, stimulates chlorophyll loss, enhances excessive softening, promotes discoloration and browning during storage of fresh produce. Among the techniques used to remove or inhibit ethylene action during postharvest handling of fresh products (potassium-based system, high temperature catalytic oxidation, inhibition of ethylene receptors), the use of titanium oxide (TiO2)-based materials with photocatalytic activity under ultraviolet (UV) light is one of the most promising. A fluidised-bed photoreactor (FBP) was designed to decompose ethylene in the storage room atmosphere, and the relative prototype was manufactured. Since TiO2 powder alone is not suitable for use within a fluidised bed, preliminary tests to select the best support were performed. Alumina microspheres showed a good fluidisation behavior; its functionality was tested with different kind of support material and actual photocatalytic activity was tested using SiO2/TiO2-coated alumina microspheres. A reduction of approximately 72% of ethylene concentration in the tested 40 ppm ethylene gas mixture was observed after 4.5 h of 36W UV light exposure. FBP resulted to be suitable to avoid the detrimental presence of C2H4 in the atmosphere surrounding fresh products within cold storage rooms