Fractal to Nonfractal Phase Transition in the Dielectric Breakdown Model

A fast method is presented for simulating the dielectric-breakdown model using iterated conformal mappings. Numerical results for the dimension and for corrections to scaling are in good agreement with the recent RG prediction of an upper critical $\eta_c=4$, at which a transition occurs between branching fractal clusters and one-dimensional nonfractal clusters.Comment: 5 pages, 7 figures; corrections to scaling include

Anthocyanins are Key Regulators of Drought Stress Tolerance in Tobacco

Abiotic stresses will be one of the major challenges for worldwide food supply in the near future. Therefore, it is important to understand the physiological mechanisms that mediate plant responses to abiotic stresses. When subjected to UV, salinity or drought stress, plants accumulate specialized metabolites that are often correlated with their ability to cope with the stress. Among them, anthocyanins are the most studied intermediates of the phenylpropanoid pathway. However, their role in plant response to abiotic stresses is still under discussion. To better understand the effects of anthocyanins on plant physiology and morphogenesis, and their implications on drought stress tolerance, we used transgenic tobacco plants (AN1), which over-accumulated anthocyanins in all tissues. AN1 plants showed an altered phenotype in terms of leaf gas exchanges, leaf morphology, anatomy and metabolic profile, which conferred them with a higher drought tolerance compared to the wild-type plants. These results provide important insights for understanding the functional reason for anthocyanin accumulation in plants under stress

Facing metal stress by multiple strategies: morphophysiological responses of cardoon (Cynara cardunculus L.) grown in hydroponics

The contamination of environments by heavy metals has become an urgent issue causing undesirable accumulations and severe damages to agricultural crops, especially cadmium and lead which are among the most widespread and dangerous metal pollutants worldwide. The selection of proper species is a crucial step in many plant-based restoration approaches; therefore, the aim of the present work was to check for early morphophysiological responsive traits in three cultivars of Cynara cardunculus (Sardo, Siciliano, and Spagnolo), helping to select the best performing cultivar for phytoremediation. For all three tested cultivars, our results indicate that cardoon displays some morphophysiological traits to face Cd and Pb pollution, particularly at the root morphology level, element uptake ability, and photosynthetic pigment content. Other traits show instead a cultivar-specific behavior; in fact, stomata plasticity, photosynthetic pattern, and antioxidant power provide different responses, but only Spagnolo cv. achieves a successful strategy attaining a real resilience to metal stress. The capacity of Spagnolo plants to modify leaf structural and physiological traits under heavy metal contamination to maintain high photosynthetic efficiency should be considered an elective trait for its use in contaminated environments

Fractal geometry of spin-glass models

Stability and diversity are two key properties that living entities share with spin glasses, where they are manifested through the breaking of the phase space into many valleys or local minima connected by saddle points. The topology of the phase space can be conveniently condensed into a tree structure, akin to the biological phylogenetic trees, whose tips are the local minima and internal nodes are the lowest-energy saddles connecting those minima. For the infinite-range Ising spin glass with p-spin interactions, we show that the average size-frequency distribution of saddles obeys a power law $\sim w^{-D}$, where w=w(s) is the number of minima that can be connected through saddle s, and D is the fractal dimension of the phase space

Landscape statistics of the p-spin Ising model

The statistical properties of the local optima (metastable states) of the infinite range Ising spin glass with p-spin interactions in the presence of an external magnetic field h are investigated analytically. The average number of optima as well as the typical overlap between pairs of identical optima are calculated for general p. Similarly to the thermodynamic order parameter, for p>2 and small h the typical overlap q_t is a discontinuous function of the energy. The size of the jump in q_t increases with p and decreases with h, vanishing at finite values of the magnetic field.Comment: 12 pages,te

Molecular and clinical conditions associated with venous thromboembolism in oncological patients

The association between cancer and thrombophilia has been known since 1865 since Trousseau described it. However in the last three decades an increased interest has been raised on this issue related to several molecular and condition that are involved in the daily management of oncological patients. This brief review has been focused on molecular conditions underlying cancer acquired thrombophilia then to further clinical aspects inducing thrombophilia in oncological patients such as surgery, chemotherapy, concomitant medical illness and inherited thrombophilia.Связь между опухолевым процессом и гематогенной тромбофилией известна с 1865 г., когда Trousseau впервые дал ее описание. В последнее время отмечают возрастающий интерес к этой проблеме и связанным с ней молекулярным и клиническим параметрам, которые учитываются при постоянном наблюдении за больными онкологического профиля. Данный короткий обзор литературы посвящен характеристике молекулярных факторов, лежащих в основе тромбофилии, возникающей в процессе развития новообразований, а также другим особенностям клинического течения, индуцирующим тромбофилию у больных онкологического профиля, таким как хирургическое вмешательство, химиотерапия, сопутствующие осложнения и наследственная тромбофили

Curvature fluctuations and Lyapunov exponent at Melting

We calculate the maximal Lyapunov exponent in constant-energy molecular dynamics simulations at the melting transition for finite clusters of 6 to 13 particles (model rare-gas and metallic systems) as well as for bulk rare-gas solid. For clusters, the Lyapunov exponent generally varies linearly with the total energy, but the slope changes sharply at the melting transition. In the bulk system, melting corresponds to a jump in the Lyapunov exponent, and this corresponds to a singularity in the variance of the curvature of the potential energy surface. In these systems there are two mechanisms of chaos -- local instability and parametric instability. We calculate the contribution of the parametric instability towards the chaoticity of these systems using a recently proposed formalism. The contribution of parametric instability is a continuous function of energy in small clusters but not in the bulk where the melting corresponds to a decrease in this quantity. This implies that the melting in small clusters does not lead to enhanced local instability.Comment: Revtex with 7 PS figures. To appear in Phys Rev

Aszites, Pfortaderthrombose und hepatische Enzephalopathie bei Leberzirrhose: Aktuelle Therapieempfehlungen

Treatment of Ascites, Portal Vein Thrombosis and Hepatic Encephalopathy in Patients with Cirrhosis of the Liver Background: Ascites, portal vein thrombosis and hepatic encephalopathy are important complications of cirrhosis of the liver. Guidelines for the treatment of ascites have recently been published. Method: This manuscript summarizes up-to-date recommendations on the basis of the DGVS S3 guideline and of other guidelines as well as of the authors' experience. Results and Conclusions: TIPS (transjugular intrahepatic porto-systemic shunt) is the preferred treatment for refractory or recidivant ascites unless there are contraindications. The therapy of hepatorenal syndrome type 1 with albumin and the vasoconstrictor Terlipressin has been proven effective. Treatment of portal vein thrombosis comprises a strategy of anticoagulation, TIPS and liver transplantation. The most important therapeutic strategy for hepatic encephalopathy is the search for as well as the treatment of trigger events. Rifaximin is being increasingly used for the treatment and prophylaxis of hepatic encephalopathy