Auxetic regions in large deformations of periodic frameworks

In materials science, auxetic behavior refers to lateral widening upon stretching. We investigate the problem of finding domains of auxeticity in global deformation spaces of periodic frameworks. Case studies include planar periodic mechanisms constructed from quadrilaterals with diagonals as periods and other frameworks with two vertex orbits. We relate several geometric and kinematic descriptions.Comment: Presented at the International Conference on "Interdisciplinary Applications of Kinematics" (IAK18), Lima, Peru, March 201

Social Simulation That 'Peers into Peer Review'

This article suggests to view peer review as a social interaction problem and shows reasons for social simulators to investigate it. Although essential for science, peer review is largely understudied and current attempts to reform it are not supported by scientific evidence. We suggest that there is room for social simulation to fill this gap by spotlighting social mechanisms behind peer review at the microscope and understanding their implications for the science system. In particular, social simulation could help to understand why voluntary peer review works at all, explore the relevance of social sanctions and reputational motives to increase the commitment of agents involved, cast light on the economic cost of this institution for the science system and understand the influence of signals and social networks in determining biases in the reviewing process. Finally, social simulation could help to test policy scenarios to maximise the efficacy and efficiency of various peer review schemes under specific circumstances and for everyone involved.Peer Review, Social Simulation, Social Norms, Selection Biases, Science Policy

Pulsational and evolutionary analysis of the double-mode RR Lyrae star BS Com

We derive the basic physical parameters of the field double-mode RR Lyrae star BS Com from its observed periods and the requirement of consistency between the pulsational and evolutionary constraints. By using the current solar-scaled horizontal branch evolutionary models of Pietrinferni et al. (2004) and our linear non-adiabatic purely radiative pulsational models, we get M/M(Sun) = 0.698 +/- 0.004, log(L/L(Sun)) = 1.712 +/- 0.005, T(eff) = 6840 +/- 14 K, [Fe/H] = -1.67 +/- 0.01, where the errors are standard deviations assuming uniform age distribution along the full range of uncertainty in age. The last two parameters are in a good agreement with the ones derived from the observed BVIc colours and the updated ATLAS9 stellar atmosphere models. We get T(eff) = 6842 +/- 10 K, [Fe/H] = -1.58 +/- 0.11, where the errors are purely statistical ones. It is remarkable that the derived parameters are nearly independent of stellar age at early evolutionary stages. Later stages, corresponding to the evolution toward the asymptotic giant branch are most probably excluded because the required high temperatures are less likely to satisfy the constraints posed by the colours. We also show that our conclusions are only weakly sensitive to nonlinear period shifts predicted by current hydrodynamical models.Comment: Accepted for publication by MNRAS on 2008 February 01. The paper contains 4 figures and 8 table

The Evolution of Altruism in Spatially Structured Populations

The evolution of altruism in humans is still an unresolved puzzle. Helping other individuals is often kinship-based or reciprocal. Several examples show, however, that altruism goes beyond kinship and reciprocity and people are willing to support unrelated others even when this is at a cost and they receive nothing in exchange. Here we examine the evolution of this "pure" altruism with a focus on altruistic teaching. Teaching is modeled as a knowledge transfer which enhances the survival chances of the recipient, but reduces the reproductive efficiency of the provider. In an agent-based simulation we compare evolutionary success of genotypes that have willingness to teach with those who do not in two different scenarios: random matching of individuals and spatially structured populations. We show that if teaching ability is combined with an ability to learn and individuals encounter each other on a spatial proximity basis, altruistic teaching will attain evolutionary success in the population. Settlement of the population and accumulation of knowledge are emerging side-products of the evolution of altruism. In addition, in large populations our simple model also produces a counterintuitive result that increasing the value of knowledge keeps fewer altruists alive.Altruism, Teaching, Knowledge Transfer, Spatially Structured Social Dilemmas

The 3rd Flow Component as a QGP Signal

Earlier fluid dynamical calculations with QGP show a softening of the directed flow while with hadronic matter this effect is absent. On the other hand, we indicated that a third flow component shows up in the reaction plane as an enhanced emission, which is orthogonal to the directed flow. This is not shadowed by the deflected projectile and target, and shows up at measurable rapidities, $y_cm = 1-2$. To study the formation of this effect initial stages of relativistic heavy ion collisions are studied. An effective string rope model is presented for heavy ion collisions at RHIC energies. Our model takes into account baryon recoil for both target and projectile, arising from the acceleration of partons in an effective field. The typical field strength (string tension) for RHIC energies is about 5-12 GeV/fm, what allows us to talk about "string ropes". The results show that QGP forms a tilted disk, such that the direction of the largest pressure gradient stays in the reaction plane, but deviates from both the beam and the usual transverse flow directions. The produced initial state can be used as an initial condition for further hydrodynamical calculations. Such initial conditions lead to the creation of third flow component. Recent $v_1$ measurements are promising that this effect can be used as a diagnostic tool of the QGP

Subcellular partitioning of MRP RNA assessed by ultrastructural and biochemical analysis.

A small RNA encoded within the nucleus is an essential subunit of a RNA processing endonuclease (RNase MRP) hypothesized to generate primers for mitochondrial DNA replication from the heavy strand origin of replication. Controversy has arisen, however, concerning the authenticity of an intramitochondrial pool of MRP RNA, and has called into question the existence of pathways for nucleo-mitochondrial transport of nucleic acids in animal cells. In an effort to resolve this controversy, we combined ultrastructural in situ hybridization and biochemical techniques to assess the subcellular partitioning of MRP RNA. Cryosections of mouse cardiomyocytes were hybridized with biotin-labeled RNA probes complementary to different regions of MRP RNA and varying in length from 115 to 230 nucleotides, followed by immunogold labeling. In addition, we transfected mouse C2C12 myogenic cells with constructs bearing mutated forms of the mouse MRP RNA gene and compared the relative abundance of the resulting transcripts to that of control RNAs within whole cell and mitochondrial fractions. In the former analysis we observed preferential localization of MRP RNA to nucleoli and mitochondria in comparison to the nucleoplasm and cytoplasm. In the latter series of studies we observed that wild-type MRP RNA partitions to the mitochondrial fraction by comparison to other RNA transcripts that are localized to the extramitochondrial cytoplasmic space (28S rRNA) or to the nucleoplasm (U1 snRNA). Deletions within 5' or 3' regions of the MRP RNA gene produced transcripts that remain competent for mitochondrial targeting. In contrast, deletion of the midportion of the coding region (nt 118 to 175) of the MRP RNA gene resulted in transcripts that fail to partition to the mitochondrial fraction. We conclude that an authentic intramitochondrial pool of MRP RNA is present in these actively respiring cells, and that specific structural determinants within the MRP RNA molecule permit it to be partitioned to mitochondria

Chondroid Syringoma and Eccrine Spiradenoma

Fine needle aspiration cytology (FNAC) is a well established diagnostic tool. However, most clinicians prefer to diagnose suspected skin tumors by excisional biopsy as they are easily accessible and hence benign skin adnexal tumors are rarely encountered on FNAC. There are only a very few case reports describing the fine needle aspiration cytologic features of chondroid syringoma and eccrine spiradenoma for diagnosis. Cases: First case was a 20 year old female who presented with firm,non-tender swelling in the left little finger measuring 1 cm in diameter. Smears showed clusters of round to plasmacytoid cells with moderate to abundant cytoplasm embedded in a chondromyxoid ground substance . Hence, a diagnosis of chondroid syringoma was made. Another case was a 40 year old lady who presented with a painful swelling on the anterior chest wall measuring approximately 0.8 cms in diameter. Smears were moderately cellular with cohesive sheets and clusters of bland cells of three different cell types. Hence, a probable diagnosis of eccrine spiradenoma was made and both the cases were confirmed histologically. Conclusion: Appropriate knowledge of the cytologic features of chondroid syringoma and eccrine spiradenoma helps in providing a definitive diagnosis and correct management of the patient

Luxury Brand Licensing: Competition and Reference Group Effects

Marketing research has traditionally focused on centralized brand-extension strategies where a brand expands its product offerings by controlling the design, production, marketing and sales of new products `in-house'. However, luxury brands frequently use `brand licensing' as a decentralized brand-extension strategy under which a brand licenses its brand name to an `external licensee' that designs, produces and sells the new product. Licensing is a time-efficient and cost-effective brand-extension strategy for luxury brands to reach out to their aspirational, low-end consumers (`followers') who value a brand more when more high-end consumers (`snobs') purchase the brand's primary product (i.e., `positive popularity effect'). On the other hand, over-licensing might dilute the brand for snobs who value brand exclusivity (i.e., `negative popularity effect'). We develop a game-theoretic model to study luxury brand licensing in the presence of these two countervailing forces. First, in the monopoly setting (a benchmark), we find that the monopoly brand should license only when the negative popularity effect is not too high, and it should prefer `royalty licensing' over `fixed-fee licensing' when the negative popularity effect is intermediate. Second, to explicate our analysis, we study the duopoly setting under fixed-fee contracts. In contrast to the monopoly setting, we find that fixed-fee licensing can `soften' price competition between brands so that licensing is `always' profitable for both brands under competition. Interestingly, in equilibrium under fixed-fee contracts, competing brands face a prisoner's dilemma and both brands prefer not to license, even though both would be better off if they could commit to fixed-fee licensing. Finally, we expand our analysis of the duopoly model by incorporating royalty licensing in addition to fixed-fee licensing. We find that, in contrast to fixed-fee licensing, royalty licensing can `intensify' price competition so that both brands have to lower their prices. Consequently, when the positive popularity effect is sufficiently strong, fixed-fee licensing `dominates' royalty licensing. We also show that, under competition, luxury brands should adopt royalty contracts only when the licensing market is large, and positive and negative popularity effects are small enough

CVaR minimization by the SRA algorithm

Using the risk measure CV aR in �nancial analysis has become more and more popular recently. In this paper we apply CV aR for portfolio optimization. The problem is formulated as a two-stage stochastic programming model, and the SRA algorithm, a recently developed heuristic algorithm, is applied for minimizing CV aR