Simplifying Random Satisfiability Problem by Removing Frustrating Interactions

How can we remove some interactions in a constraint satisfaction problem (CSP) such that it still remains satisfiable? In this paper we study a modified survey propagation algorithm that enables us to address this question for a prototypical CSP, i.e. random K-satisfiability problem. The average number of removed interactions is controlled by a tuning parameter in the algorithm. If the original problem is satisfiable then we are able to construct satisfiable subproblems ranging from the original one to a minimal one with minimum possible number of interactions. The minimal satisfiable subproblems will provide directly the solutions of the original problem.Comment: 21 pages, 16 figure

Jordan derivations on certain Banach algebras

In this paper, we study the types of Jordan derivations of a Banach algebra $A$ with a right identity $e$. We show that if $eA$ is commutative and semisimple, then every Jordan derivation of $A$ is a derivation. In this case, Jordan derivations map $A$ into the radical of $A$. We also prove that every Jordan triple left (right) derivation of $A$ is a Jordan left (right) derivation. Finally, we investigate the range of Jordan left derivations and establish that every Jordan left derivation of $A$ maps $A$ into $eA$

Causative factors behind poloxamer 188 (Pluronic F68, Flocor™)-induced complement activation in human sera A protective role against poloxamer-mediated complement activation by elevated serum lipoprotein levels

AbstractPoloxamer 188 is a complex polydisperse mixture of non-ionic macromolecules. Adverse non-IgE-mediated hypersensitivity reactions occur in some individuals following intravenous injection of poloxamer 188-based pharmaceuticals, presumably via complement activation. Here we have delineated potential causal chemical and biological interactive factors behind poloxamer 188-induced complement activation in human serum specimens. We identified the molecular constituents inherent in poloxamer 188 preparations and studied their effect on generation of the two complement split products, SC5b-9 and Bb. Poloxamer 188 activated complement at sub-micellar concentrations and the results indicated the potential involvement of all three known complement activation pathways. The poloxamer-induced rise of SC5b-9 in human sera was abolished in the presence of a recombinant truncated soluble form of complement receptor type 1, thus confirming the role of C3/C5 convertases in the activation process. Poloxamer 188-mediated complement activation is an intrinsic property of these macromolecules and was independent of the degree of sample polydispersity, as opposed to other non-polymeric constituents. Poloxamer 188 preparations also contained unsaturated chains of diblock copolymers capable of generating SC5b-9 in human sera; this effect was terminated following the removal of double bonds by catalytic hydrogenation. By quasi-elastic light scattering, we established interaction between poloxamer and lipoproteins; interestingly, poloxamer-induced rise in SC5b-9 was significantly suppressed when serum HDL and LDL cholesterol levels were increased above normal to mimic two relevant clinical situations. This observation was consistent with previously reported data from patients with abnormal or elevated lipid profiles where no or poor complement activation by poloxamer 188 occurred. Our findings could provide the basis of novel approaches to the prevention of poloxamer-mediated complement activation

Spanning Trees in Random Satisfiability Problems

Working with tree graphs is always easier than with loopy ones and spanning trees are the closest tree-like structures to a given graph. We find a correspondence between the solutions of random K-satisfiability problem and those of spanning trees in the associated factor graph. We introduce a modified survey propagation algorithm which returns null edges of the factor graph and helps us to find satisfiable spanning trees. This allows us to study organization of satisfiable spanning trees in the space spanned by spanning trees.Comment: 12 pages, 5 figures, published versio

Numerical and Experimental Investigations on Aerodynamic Behavior of the Ahmed Body Model with Different Diffuser Angles

Due to many restrictions applied by the necessity of fulfilling dimensional analysis in a numerical-experimental research and also the limits in experimental facilities a Low Reynolds Number simulation seems to be widespread. In this paper, effects of the diffuser angle on the aerodynamic behavior of the Ahmed body have been investigated for low Reynolds number flows. Numerical simulations were performed by solving the Reynolds Averaged Navier-Stokes (RANS) equations combined with different turbulence models. The Finite Volume Method (FVM) is used for simulations in Fluent 6.3.26 Software. The main objectives of the study are to improve the aerodynamic design of the body, analyzing the flow field to understand the nature of these improvements and reaching a suitable and reliable experimental-numerical setup for such a flow. Finally, it was concluded that the SST k-ω turbulence model with transitional flow corrections is the best choice. From the flow simulation and obtained experimental data, it was concluded that that drag coefficient is a function of three main phenomena. Results showed that the drag coefficient has its minimum value at a specific diffuser angle (8◦) and further increases in the angle lead to higher drag coefficient. On the other hand, the lift coefficient constantly decreases by increasing the diffuser angle. In order to show the validity of the numerical results, experimental data were obtained by measuring the drag and lift coefficients of scaled standard Ahmed body and a model with the diffuser angle of 8 degrees in a wind tunnel. Results confirmed that improvement of drag and lift coefficients occurs when diffuser region is considered for the Ahmed body. In addition, the flow field around the body was studied in detail to show the effects of the diffuser geometry on the aerodynamic characteristics of the body

Core (Polystyrene)−Shell [Poly(glycerol monomethacrylate)] Particles

YesA set of water-swollen core−shell particles was synthesized by emulsion polymerization of a 1,3-dioxolane functional monomer in water. After removal of the 1,3- dioxolane group, the particles’ shells were shown to swell in aqueous media. Upon hydrolysis, the particles increased in size from around 70 to 100−130 nm. A bicinchoninic acid assay and ζ-potential measurements were used to investigate the adsorption of lysozyme, albumin, or fibrinogen. Each of the core−shell particles adsorbed significantly less protein than the noncoated core (polystyrene) particles. Differences were observed as both the amount of difunctional, cross-linking monomer and the amount of shell monomer in the feed were changed. The core−shell particles were shown to be resistant to protein adsorption, and the degree to which the three proteins adsorbed was dependent on the formulation of the shell.EPSRC and MR

Evaluation of the end colostomy complications and the risk factors influencing them in Iranian patients

Introduction: The aim of this study was to assess the prevalence of end colostomy complications and the evaluation of factors influencing outcome. Patients and methods: Three hundred and thirty patients with end colostomy were studied. All patient were recalled for examination for recent complications. Early complications included stoma site pain, early dermal irritation (during the first month after surgery), mucosal bleeding, stornal prolapse and psychosocial complications. Late complications included peristomal hernia, stomal stenosis, late dermal irritation (after the first month), stomal retraction, stomal necrosis and other stoma complications (perforation, fistula etc.). Probable underlying factors were studied. To evaluate risk factors affecting complications, univariable analysis and then multivariable analysis by binary logistic regression was performed. Results: One hundred and one (30.6) patients had no complications and the remainder had at least one of early or late complications. Overall, psychosocial complications, 56.4; mucosal bleeding, 34.5; early dermal irritation, 23.5 were the most frequent complications. Peristomal hernia (11.2) was the most common late complication. Those aged >40 years had significant associations with psychosocial problem (OR = 2.77), mucosal haemorrhage (OR = 2.19), and early dermal irritation (OR = 3.14). The risks of peristomal hernia and early dermal irritation are greater in the patients with BMI >25 kg/m2 (OR = 2.08 and 2.55, respectively). Conclusion: The risk of most prevalent complications of colostomy construction increases in elder patients. The high prevalence of psychosocial and skin problems in patients with a colostomy, needs special attention especially from the viewpoint of education by trained stoma nurses and preparation of standard equipment. © 2005 Blackwell Publishing Ltd

Abelian Sandpile Model on the Honeycomb Lattice

We check the universality properties of the two-dimensional Abelian sandpile model by computing some of its properties on the honeycomb lattice. Exact expressions for unit height correlation functions in presence of boundaries and for different boundary conditions are derived. Also, we study the statistics of the boundaries of avalanche waves by using the theory of SLE and suggest that these curves are conformally invariant and described by SLE2.Comment: 24 pages, 5 figure

Can the Relationship between Doctors and Drug Companies Ever Be a Healthy One?

Emma D'Arcy and Ray Moynihan debate whether doctors and drug companies can form healthy alliances or whether these will always be prone to the corrupting influence of drug company money