Time persistency of floating particle clusters in free-surface turbulence

We study the dispersion of light particles floating on a flat shear-free surface of an open channel in which the flow is turbulent. This configuration mimics the motion of buoyant matter (e.g. phytoplankton, pollutants or nutrients) in water bodies when surface waves and ripples are smooth or absent. We perform direct numerical simulation of turbulence coupled with Lagrangian particle tracking, considering different values of the shear Reynolds number (Re{\tau} = 171 and 509) and of the Stokes number (0.06 < St < 1 in viscous units). Results show that particle buoyancy induces clusters that evolve towards a long-term fractal distribution in a time much longer than the Lagrangian integral fluid time scale, indicating that such clusters over-live the surface turbulent structures which produced them. We quantify cluster dynamics, crucial when modeling dispersion in free-surface flow turbulence, via the time evolution of the cluster correlation dimension

Allium albanicum (Amaryllidaceae), a new species from Balkans and its relationships with A. meteoricum Heldr. & Hausskn. ex Halácsy

A new species, Allium albanicum, is described and illustrated from Albania (Balkan Peninsula). It grows on serpentines or limestone in open rocky stands with a scattered distribution, mainly in mountain locations. Previously, the populations of this geophyte were attributed to A. meteoricum Heldr. &amp; Hausskn. ex Halácsy, described from a few localities of North and Central Greece. These two species indeed show close relationships, chiefly regarding some features of the spathe valves, inflorescence and floral parts. They also share the same diploid chromosome number 2n =16 and similar karyotype, while seed testa micro-sculptures and leaf anatomy reveal remarkable differences. There are also several morphological features that allow them to be differentiated at specific level. The inclusion of both species into a newly described section Pseudoscorodon of the subgen. Allium is proposed. An analytic key to the species, included in the new section, is also provided

Static and Dynamic 4-Way Handshake Solutions to Avoid Denial of Service Attack in Wi-Fi Protected Access and IEEE 802.11i

This paper focuses on WPA and IEEE 802.11i protocols that represent two important solutions in the wireless environment. Scenarios where it is possible to produce a DoS attack and DoS flooding attacks are outlined. The last phase of the authentication process, represented by the 4-way handshake procedure, is shown to be unsafe from DoS attack. This can produce the undesired effect of memory exhaustion if a flooding DoS attack is conducted. In order to avoid DoS attack without increasing the complexity of wireless mobile devices too much and without changing through some further control fields of the frame structure of wireless security protocols, a solution is found and an extension of WPA and IEEE 802.11 is proposed. A protocol extension with three "static" variants and with a resource-aware dynamic approach is considered. The three enhancements to the standard protocols are achieved through some simple changes on the client side and they are robust against DoS and DoS flooding attack. Advantages introduced by the proposal are validated by simulation campaigns and simulation parameters such as attempted attacks, successful attacks, and CPU load, while the algorithm execution time is evaluated. Simulation results show how the three static solutions avoid memory exhaustion and present a good performance in terms of CPU load and execution time in comparison with the standard WPA and IEEE 802.11i protocols. However, if the mobile device presents different resource availability in terms of CPU and memory or if resource availability significantly changes in time, a dynamic approach that is able to switch among three different modalities could be more suitable

Taxonomical and chorological remarks on the Mediterranean Poa maroccana (Poaceae) and the first record in Italy from the Sicilian flora

Poa maroccana is an annual Mediterranean species, which is recorded for the first time from Sicily and for the entire territory of Italy. It usually occurs in synanthopic habitats, represented mainly by urban and suburban roadsides, where it is quite sporadic. Based on current knowledge, it has been hitherto reported only in a few localities of the Mediterranean area, specifically in Morocco, Algeria, Tunisia, Libya, Spain, Portugal, Greece, Turkey, Syria and Crimea. Field observations and herbarium investigations have shown that this species is often mistaken for P. annua, mainly due to its morphological similarities, as well as for having the same ecological needs, therefore its real geographical distribution has yet to be verified. Although the two species are both tetraploids (2n = 28), they clearly differ in numerous relevant features concerning the shape and size of ligules, inflorescence, spikelet, glumes, palea, lemma, anthers, lodicules and seed. In order to better clarify the relationships of P. maroccana with P. annua and other annual species of this genus occurring in the Mediterranean, a careful morphological description and an iconography are provided, as well as a comparative morphological table of all allied species and also an analytical key for their easy identification

The risk of bleeding and encephalopathy in surgical patients with liver cirrhosis

Liver cirrhosis is a disease with an increasing incidence. Surgical procedures in patients with cirrhosis are also increasing, due to a longer life expectancy in these patients and also to the improvement of therapeutic and diagnostic resources. Digestive hemorrhage in the cirrhotic patient requires emergency medical intervention (intensive therapy, endoscopic or even surgical approaches), being at the same time a factor that precipitates episodes of encephalopathy, i.e. the conventional complication of cirrhosis. Hepatic encephalopathy represents one of the most severe clinical events of cirrhosis, being associated with high morbidity and mortality. The causes of hepatic encephalopathy are briefly presented in this paper. Therapeutic approaches currently available consist in the administration of non-absorbable disaccharides such as lactulose and non-absorbable antibiotics such as rifaximin. New therapeutic perspectives are under evaluation, e.g. ammonia scavengers and the modulation of gut microbiota. Clotting disorders in patients with liver cirrhosis are more severe as the disease progresses and involves complex mechanisms, as presented in this review. The correction of possible disorders of hemostasis should be promptly made as a sine qua non condition prior to surgery

Palmitoylethanolamide and related ALIAmides: prohomeostatic pipid compounds for animal health and wellbeing

Virtually every cellular process is affected by diet and this represents the foundation of dietary management to a variety of small animal disorders. Special attention is currently being paid to a family of naturally occurring lipid amides acting through the so-called autacoid local injury antagonism, i.e., the ALIA mechanism. The parent molecule of ALIAmides, palmitoyl ethanolamide (PEA), has being known since the 1950s as a nutritional factor with protective properties. Since then, PEA has been isolated from a variety of plant and animal food sources and its proresolving function in the mammalian body has been increasingly investigated. The discovery of the close interconnection between ALIAmides and the endocannabinoid system has greatly stimulated research efforts in this field. The multitarget and highly redundant mechanisms through which PEA exerts prohomeostatic functions fully breaks with the classical pharmacology view of “one drug, one target, one disease”, opening a new era in the management of animals’ health, i.e., an according-to-nature biomodulation of body responses to different stimuli and injury. The present review focuses on the direct and indirect endocannabinoid receptor agonism by PEA and its analogues and also targets the main findings from experimental and clinical studies on ALIAmides in animal health and wellbeing

SerpinB3 promotes pro-fibrogenic responses in activated hepatic stellate cells

SerpinB3 is a hypoxia- and hypoxia-inducible factor-2\u3b1-dependent cystein protease inhibitor that is up-regulated in hepatocellular carcinoma and in parenchymal cells during chronic liver diseases (CLD). SerpinB3 up-regulation in CLD patients has been reported to correlate with the extent of liver fibrosis and the production of transforming growth factor-\u3b21, but the actual role of SerpinB3 in hepatic fibrogenesis is still poorly characterized. In the present study we analyzed the pro-fibrogenic action of SerpinB3 in cell cultures and in two different murine models of liver fibrosis. "In vitro" experiments revealed that SerpinB3 addition to either primary cultures of human activated myofibroblast-like hepatic stellate cells (HSC/MFs) or human stellate cell line (LX2 cells) strongly up-regulated the expression of genes involved in fibrogenesis and promoted oriented migration, but not cell proliferation. Chronic liver injury by CCl4 administration or by feeding a methionine/choline deficient diet to transgenic mice over-expressing human SerpinB3 in hepatocytes confirmed that SerpinB3 over-expression significantly increased the mRNA levels of pro-fibrogenic genes, collagen deposition and \u3b1SMA-positive HSC/MFs as compared to wild-type mice, without affecting parenchymal damage. The present study provides for the first time evidence that hepatocyte release of SerpinB3 during CLD can contribute to liver fibrogenesis by acting on HSC/MFs

Nb superconductive thin film coating on flat Cu disks for high gradient applications

In this work we present the characterization of Nb superconductive films deposed on copper substrates with two different techniques: the PVD magnetron sputtering and the Pulsed Laser Ablation. In the first method Nb films ∼ 3µm thick were deposited with an average roughness of 160 nm. The superconductivity properties of these films were also determined with a 4-probe resistivity measurement. Data show a superconducting transition at 9.6K as expected from Nb films. With the second technique thick Nb films were deposited on copper substrates using the Pulsed Laser Ablation. In this case the Rutherford Backscattering was used to determine the thickness and the chemical state of these films that show different degrees of oxidation