A new nonlocal nonlinear diffusion equation for image denoising and data analysis

In this paper we introduce and study a new feature-preserving nonlinear anisotropic diffusion for denoising signals. The proposed partial differential equation is based on a novel diffusivity coefficient that uses a nonlocal automatically detected parameter related to the local bounded variation and the local oscillating pattern of the noisy input signal. We provide a mathematical analysis of the existence of the solution of our nonlinear and nonlocal diffusion equation in the two dimensional case (images processing). Finally, we propose a numerical scheme with some numerical experiments which demonstrate the effectiveness of the new method

First--order continuous models of opinion formation

We study certain nonlinear continuous models of opinion formation derived from a kinetic description involving exchange of opinion between individual agents. These models imply that the only possible final opinions are the extremal ones, and are similar to models of pure drift in magnetization. Both analytical and numerical methods allow to recover the final distribution of opinion between the two extremal ones.Comment: 17 pages, 4 figure

Estimation of traf- fic matrices in the presence of long memory traffic

The estimation of traffic matrices in a communications network on the basis of a set of traffic measurements on the network links is a well-known problem, for which a number of solutions have been proposed when the traffic does not show dependence over time, as in the case of the Poisson process. However, extensive measurements campaigns conducted on IP networks have shown that the traffic exhibits long range dependence. Here a method is proposed for the estimation of traffic matrices in the case of long range dependence, and its theoretical properties are studied. Its merits are then evaluated via a simulation study. Finally, an application to real data is provided

A rank-and-compare algorithm to detect abnormally low bids in procurement auctions

3noDetecting abnormally low bids in procurement auctions is a recognized problem, since their acceptance could result in the winner not being able to provide the service or work awarded by the auction, which is a significant risk for the auctioneer. A rank-and-compare algorithm is considered to detect such anomalous bids and help auctioneers in achieving an effective rejection decision. Analytical expressions and simulation results are provided for the detection probability, as well as for the false alarm probability. The suggested range of application of the detection algorithm leaves out the cases of many tenderers (more than 20) and quite dispersed bids (coefficient of variation larger than 0.15). An increase in the number of tenderers leads to contrasting effects, since both the false alarm probability and the detection probability are reduced. If the bids are spread over a large range, we have instead a double negative effect, with more false alarms and less detections. The presence of multiple anomalous bids worsens the performance of the algorithm as well. On the other hand, the method is quite robust to the presence of courtesy bids.reservedmixedL. De Giovanni; P. L. Conti; M. NaldiDE GIOVANNI, Livia; P. L., Conti; M., Nald

A Bistable Model of Cell Polarity

Ultrasensitivity, as described by Goldbeter and Koshland, has been considered for a long time as a way to realize bistable switches in biological systems. It is not as well recognized that when ultrasensitivity and reinforcing feedback loops are present in a spatially distributed system such as the cell plasmamembrane, they may induce bistability and spatial separation of the system into distinct signaling phases. Here we suggest that bistability of ultrasensitive signaling pathways in a diffusive environment provides a basic mechanism to realize cell membrane polarity. Cell membrane polarization is a fundamental process implicated in several basic biological phenomena, such as differentiation, proliferation, migration and morphogenesis of unicellular and multicellular organisms. We describe a simple, solvable model of cell membrane polarization based on the coupling of membrane diffusion with bistable enzymatic dynamics. The model can reproduce a broad range of symmetry-breaking events, such as those observed in eukaryotic directional sensing, the apico-basal polarization of epithelium cells, the polarization of budding and mating yeast, and the formation of Ras nanoclusters in several cell types

Antitumoral Efficacy of Two Turmeric Extracts According to Different Extraction Methods in Hepatocellular Carcinoma Cell Lines

Curcuminoids, bioactive molecules contained in turmeric, have been reported to exert anticancer effects in several human cancers, including hepatocellular carcinoma (HCC). However, the extraction method can significantly affect the structural characteristics of curcuminoids and their biological properties. On this basis, in the present study we investigated the content of curcuminoids and the anticancer activity of two turmeric powders extracted according two different methodologies: solvent extraction with ethyl acetate vs an ancient Indian extraction method of boiling of rhizomes in water followed by dehydration at the sun. Results obtained showed that extraction with ethyl acetate resulted in a significant recovery of curcuminoids and anticancer activity both in terms of cell cytotoxicity and migration/invasiveness inhibition in HCC cell lines, compared to common Indian practice. Overall these findings suggest that turmeric powders could have different efficacy, depending on the extraction method. This aspect should be taken into account when choosing the best product to be employed in the prevention and treatment of human diseases, including cancer

Kumulativni traumatski poremećaji gornjih udova u radnika na poljoprivrednom dobru

The work associated with repetitive efforts and inadequate resting periods, strong physical exertion, awkward postures or static positioning exposes workers to the risk of cumulative trauma disorders of the upper limbs. These risk factors are present in many agricultural activities. A study was carried out among workers on an agricultural farm. The workers\u27 histories were taken and they were given periodical medical check-ups. The presence of upper limb disorders was shown in a group of workers. A sample of 42 people was selected for the study by means of specific tests: electromyography, ultrasonography and laser-doppler ftowmetry. The tests showed a high incidence of carpal tunnel syndrome and microcirculation disorders. The study confirmed that electromyography, ultrasonography and/or laser-doppler flowmetry are highly useful tools for identifying cumulative trauma disorders.Pokreti koji se ponavljaju, neprimjereni odmori, teška fizička opterećenja te nefiziološki položaji tijela dovode do povećanog rizika razvoja bolesti kumulativne traume gornjih udova. Ovi čimbenici rizika prisutni su u mnogim poljoprivrednim djelatnostima. Od 74 radnika na poljoprivrednom dobru podvrgnuta periodskim pregledima, u 42 je primijenjena elektromiografija, ultrasonografija i mjerenje krvnog protoka laser-doppler metodom. Testovima je utvrđena visoka učestalost sindroma karpalnog tunela i poremećaja mikrocirkulacije. Ispitivanje je potvrdilo da su eiektromiografija, ultrasonografija i/ili laser-doppler mjerenje krvnog protoka veoma korisne metode u dijagnostici bolesti kumulativne traume

Vrtlarski rad i izloženost teškim metalima u gradskom okružju

Urban soil may be a source of occupational exposure to various pollutants in gardening and land cultivation. This paper presents data of a one-year follow-up of lead, cadmium, nickel, chromium, and vanadium in the environment of the city of Bologna. Samples of soil and leaves were collected at three locations; gardens from the inner-city high-traffic area, parks in moderatetraffic area, and parks in suburban, low-traffic area. The top and deeper layers of soil and leaves were mainly polluted by lead at all locations, which corresponded to the traffic density. Personal samplers recorded greater concentrations of airborne metals than did the area samplers but the values kept below the threshold limit established by the American Conference of Governmental Industrial Hygienists for the working environment. Due to cumulative nature and interactive effects of toxic metals with other toxic and essential elements, long-term exposure to metals in the urban environment may be a health risk for occupationally exposed gardeners.Gradsko tlo može biti izvorom profesionalne izloženosti različitim onečišćivačima u vrtlara, uključujući otrovne teške metale koji se talože iz onečišćenog zraka na tlo i lišće. U radu su prikazani podaci jednogodišnjeg praćenja koncentracija olova, kadmija, niklja, kroma i vanadija u talijanskom gradu Bologni. Uzorci tla i lišća skupljani su na tri mjesta s različitom gustoćom prometa; u središtu grada s velikom gustoćom prometa, u parkovima s umjerenim prometom u okolišu i u prigradskim parkovima sa slabim prometom. Na svim lokacijama gornji i dublji slojevi tla bili su podjednako onečišćeni ponajprije olovom i to je bilo u svezi s prometnom gustoćom. Koncentracije metala u zraku utvr|ene u filtrima osobnih skupljača bile su više od koncentracija u skupljačima na tlu. Vrijednosti metala u zraku bile su niže od graničnih vrijednosti utvr|enih za radni okoliš od Američke konferencije vladinih industrijskih higijeničara (American Conference of Governmental Industrial Hygienists). Zaključeno je da vrtlari, u usporedbi s općim stanovništvom, i pri niskim razinama izloženosti u gradskom okolišu imaju povećan zdravstveni rizik za štetna djelovanja otrovnih metala i drugih onečišćivača okoliša zbog dugotrajne izloženosti u svezi s njihovim radom