Abstract:
Members of the glutathione S-transferase (GST) superfamily exhibit polymorphic expression. GSTs are investigated as biomarkers of risk for various cancers, including renal cell carcinoma (RCC). The aim of this study was to test the association between GSTM1 and GSTT1 polymorphism and susceptibility to RCC, independently or in conjunction with known risk factors. Genomic DNA was isolated from 182 controls and 76 patients with RCC. GSTM1 and GSTT1 genotypes were determined by multiplex PCR. Data obtained were analyzed with respect to RCC risk factors including smoking and occupational exposure. The frequency of GSTM1-null genotype was higher in patients with RCC (60.5%) compared to controls (47.2%). GSTT1-null genotype was found in 28.6% controls and 27.6% of cases. GSTM1-null individuals exhibit 1.9-fold increased risk of RCC (95% CI: 1.06-3.33). The presence of GSTT1 active genotype was associated with increased risk of RCC in occupationally exposed subjects when unexposed GSTT1-null subjects were used as a comparison group (OR: 2.48; 95% CI: 1.05-5.86). No association was found between the inactive form of GSTM1 and GSTT1 and smoking in RCC patients. In a Serbian cohort of patients, the presence of a GSTM1 active genotype is protective against RCC, whereas a GSTT1 active genotype increases RCC risk in occupationally exposed subjects.

Abstract:
We present the results of a numerical search for periodic orbits with zero angular momentum in the Newtonian planar three-body problem with equal masses focused on a narrow search window bracketing the figure-eight initial conditions. We found eleven solutions that can be described as some power of the "figure-eight" solution in the sense of the topological classification method. One of these solutions, with the seventh power of the "figure-eight", is a choreography. We show numerical evidence of its stability.

Abstract:
Using agent-directed simulations, we investigate fluctuations in the collective emotional states on a chat network where agents interchange messages with a fixed number of moderators and emotional Bot. To design a realistic chat system, the interaction rules and some statistical parameters, as well as the agent's attributes, are inferred from the empirical chat channel \texttt{Ubuntu}. In the simulations, the Bot's emotion is fixed; the moderators tune the level of its activity by passing a fraction $\epsilon$ of messages to the Bot. At $\epsilon \gtrsim 0$, the collective emotional state matching the Bot's emotion polarity gradually arises; the average growth rate of the dominant emotional charge serves as an order parameter. Due to self-organizing effects, the collective dynamics is more explosive when positive emotions arise by positive Bot than the onset of negative emotions in the presence of negative Bot at the same $\epsilon$. Furthermore, when the emotions matching the Bot's emotion polarity are spread over the system, the underlying fractal processes exhibit higher persistence and stronger clustering of events than the processes spreading of emotion polarity opposite to the Bot's emotion. On the other hand, the relaxation dynamics is controlled by the external noise; the related nonextensive parameter, estimated from the statistics of returns, is virtually independent of the Bot's activity level and emotion contents.

Abstract:
In this paper we present the results of Monte Carlo simulations of positronium (Ps) swarm thermalization in helium (He) and water vapour. We have investigated the temporal evolution of energy and spatial parameters of the swarm and their sensitivity to the shape of the cross-section and the initial energy distribution. Positron anihilation spectroscopy (PAS) and positron emission tomography (PET) are techniques that depend on anihilation of positronium in materials and tissue. The results obtained point that the Monte Carlo technique shows good agreement with experimental results and is capable of accurately describing the behaviour of Ps particles including the energy, particle lifetime and the moment and location of the anihilation.

Abstract:
We present the results of a numerical search for periodic orbits of three equal masses moving in a plane under the influence of Newtonian gravity, with zero angular momentum. A topological method is used to classify periodic three-body orbits into families, which fall into four classes, with all three previously known families belonging to one class. The classes are defined by the orbits geometric and algebraic symmetries. In each class we present a few orbits initial conditions, 15 in all; 13 of these correspond to distinct orbits.

Abstract:
We present results of numerical calculations showing a three-body orbit's period's $T$ dependence on its topology. This dependence is a simple linear one, when expressed in terms of appropriate variables, suggesting an exact mathematical law. This is the first known relation between topological and kinematical properties of three-body systems. We have used these results to predict the periods of several sets of as yet undiscovered orbits, but the relation also indicates that the number of periodic three-body orbits with periods shorter than any finite number is countable.

Abstract:
Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values.

Abstract:
We comment on the assertion made by Caselle et al., J. Stat. Mech. 0603, P008 (2006), that the confining (string) potential for three quarks "makes a smooth cross-over transition from the Delta-string to the Y-string configuration at interquark distances of around 0.8 fm". We study the functional dependence of the three-quark confining potentials due to a Y-string, and the Delta-string and show that they have different symmetries, which lead to different constants of the motion (i.e. they belong to different "universality classes" in the parlance of the theory of phase transitions). This means that there is no "smooth cross-over" between the two, when their string tensions are identical, except at the vanishing hyper-radius. We also comment on a certain two-body potential approximation to the Y-string potential.

Abstract:
The following inverse problem is solved—given the eigenvalues and the potential b(n) for a difference boundary value problem with quadratic dependence on the eigenparameter, λ, the weights c(n)？can be uniquely reconstructed. The investi-gation is inductive on m where represents the number of unit intervals and the results obtained depend on the specific form of the given boundary conditions. This paper is a sequel to [1] which provided an algorithm for the solution of an analogous inverse problem, where the eigenvalues and weights were given and the potential was uniquely reconstructed. Since the inverse problem considered in this paper contains more unknowns than the inverse problem considered in [1], an additional spectrum is required more often than was the case in [1].

Abstract:
On an intermediate goods market with asymmetric production technologies as well
as vertical and horizontal product differentiation, we analyze the influence of simultaneous
competition for resources and customers. The intermediaries face either
price or quantity competition on the output market and a monopolistic, strategically
acting supplier on the input market. We find that there exist quality and productivity
differences such that for quantity competition only one intermediary is willing to
procure inputs from the input supplier, while for price competition both intermediaries
are willing to purchase inputs. Moreover, the well-known welfare advantage of
price competition can in general be no longer confirmed in our model with an endogenous
input market and asymmetric intermediaries.