Graphene tests of Klein phenomena

Graphene is characterized by chiral electronic excitations. As such it provides a perfect testing ground for the production of Klein pairs (electron/holes). If confirmed, the standard results for barrier phenomena must be reconsidered with, as a byproduct, the accumulation within the barrier of holes.Comment: 8 page

Shopping centres revisited: exploring new attributes of attractiveness

Traditional retailing is facing tough challenges, driven not least by the trend towards online shopping. This paper revisits shopping centres research in light of the recent increasing role of technologies, leisure activities and changes in consumer behaviour. Drawing upon 10,544 consumers’ unsolicited communications on Twitter relating to the 19 main shopping centres in UK that were posted in May 2019, this research seeks to understand how retail attributes are unevenly distributed across consumers’ evaluations to define the attributes driving consumers’ evaluations of retail-leisure complexes. Results demonstrate the impact of each identified attribute on preferences for retail-leisure complexes. In particular, findings provide important insights for scholars and practitioners related to the design of future attractive shopping centres. Shopping centres can play an important role in contributing to the viability and vitality of towns. We consider the findings in the light of wider policy and regulatory debates

Modern circular economy: Corporate strategy, supply chain, and industrial symbiosis

This paper analyses the firms\u2019 chances to consider circular economy as a part of the corporate strategy. The analysis of four Italian firms engaged in circular economy programs allows us to detect its connections with the corporate strategy, the real activities involved, the supply chain network ensuring circularity, the industrial symbiosis, as well as the links with performance. Our findings highlight that circular economy is a true business lever when the corporate strategy complements and supports its development. This allows firms to achieve high level targets that go beyond the traditional targets of social, environmental, and economic performance, and include circular supply chain, eco-innovations, and industrial symbiosis

Wave and Particle Limit for Multiple Barrier Tunneling

The particle approach to one-dimensional potential scattering is applied to non relativistic tunnelling between two, three and four identical barriers. We demonstrate as expected that the infinite sum of particle contributions yield the plane wave results. In particular, the existence of resonance/transparency for twin tunnelling in the wave limit is immediately obvious. The known resonances for three and four barriers are also derived. The transition from the wave limit to the particle limit is exhibit numerically.Comment: 15 pages, 3 figure

Evidence for impurity-induced frustration in La2CuO4

Zero-field muon spin rotation and magnetization measurements were performed in La2Cu{1-x}MxO4, for 0<x< 0.12, where Cu2+ is replaced either by M=Zn2+ or by M=Mg2+ spinless impurity. It is shown that while the doping dependence of the sublattice magnetization (M(x)) is nearly the same for both compounds, the N\'eel temperature (T_N(x)) decreases unambiguously more rapidly in the Zn-doped compound. This difference, not taken into account within a simple dilution model, is associated with the frustration induced by the Zn2+ impurity onto the Cu2+ antiferromagnetic lattice. In fact, from T_N(x) and M(x) the spin stiffness is derived and found to be reduced by Zn doping more significantly than expected within a dilution model. The effect of the structural modifications induced by doping on the exchange coupling is also discussed.Comment: 4 pages, 4 figure

Osservazioni Citotassonomiche Su Scilla Barbacaprae, Endemismo Cirenaico, E Sue Affinita' Con Scilla Villosa

RIASSUNTOViene analizzato il cariotipo di Scilla barba caprae, specie endemica di Derna (Cirenaica settentrionale). Il risultato di questa indagine, effettuata su bulbi coltivati nell'Orto Botanico di Catania, e stato il rinvenimento di un corredo cromosomico diploide: z = 2n = 2x = 14 = 2L + 2M1 + 2M2 + 2M3S3 + 2M4 + 2S1 + 2S2.La comparazione fra Scilla barba-caprae e Scilla villosa, che e la specie tassonomicamente piu vicina, ha permesso di evidenziare numerose differenze riguardanti sia il cariotipo che il fenotipo, che consentono di separare le due entita a livello specifico.In particolare il cariotipo di Scilla villosa (2n = 20) differisce da quello fondamentale 2n= 16, relativo alle entita appartenenti al ciclo di Scilla peruviana, per avere in piu quattro cromosomi, mentre quello di Scilla barba-caprae (2n = 14) ne differisce per avere due cromosomi in meno e per la presenza della coppia 2M3S3 formatasi in seguito a fenomeni di traslocazione + delezione

Barrier Paradox in the Klein Zone

We study the solutions for a one-dimensional electrostatic potential in the Dirac equation when the incoming wave packet exhibits the Klein paradox (pair production). With a barrier potential we demonstrate the existence of multiple reflections (and transmissions). The antiparticle solutions which are necessarily localized within the barrier region create new pairs with each reflection at the potential walls. Consequently we encounter a new paradox for the barrier because successive outgoing wave amplitudes grow geometrically.Comment: 10 page

Effective gluon mass and infrared fixed point in QCD

We report on a special type of solutions for the gluon propagator of pure QCD, obtained from the corresponding non-linear Schwinger-Dyson equation formulated in the Feynman gauge of the background field method. These solutions reach a finite value in the deep infrared and may be fitted using a massive propagator, with the crucial characteristic that the effective ``mass'' employed depends on the momentum transfer. Specifically, the gluon mass falls off as the inverse square of the momentum, as expected from the operator-product expansion. In addition, one may define a dimensionless quantity, which constitutes the generalization in a non-Abelian context of the universal QED effective charge. This strong effective charge displays asymptotic freedom in the ultraviolet whereas in the low-energy regime it freezes at a finite value, giving rise to an infrared fixed point for QCD.Comment: 6 pages, 2 figures, Talk given at QCD@work 2007, Martina Franca, Italy, 16-20 June 200

Secondary Baryon Asymmetry in pi(+-)p Collisions

The process of secondary baryon production in pi(+-)p collisions at high energies in the central and forward fragmentation regions is considered in the framework of the Quark-Gluon String Model. The contribution of the string-junction mechanism to the baryon production is analysed. The results of numerical calculations are in reasonable agreement with the experimental data on the Lambda/bar(Lambda) and p/bar(p)$ asymmetries.Comment: Contribution to the Proceedings of QCD@Work 2007, International Workshop on Quantum Chromodynamics, Theory and Experiment, Martina Franca-Valle d'Itria, Italy, June 16-20, 2007 (6 pages and 4 figures

Partial purification and MALDI-TOF MS analysis of UN1, a tumor antigen membrane glycoprotein.

UN1 is a membrane glycoprotein that is expressed in immature human thymocytes, a subpopulation of peripheral T lymphocytes, the HPB acute lymphoblastic leukemia (ALL) T-cell line and fetal thymus. We previously reported the isolation of a monoclonal antibody (UN1 mAb) recognizing the UN1 protein that was classified as "unclustered" at the 5th and 6th International Workshop and Conference on Human Leukocyte Differentiation Antigens. UN1 was highly expressed in breast cancer tissues and was undetected in non-proliferative lesions and in normal breast tissues, indicating a role for UN1 in the development of a tumorigenic phenotype of breast cancer cells. In this study, we report a partial purification of the UN1 protein from HPB-ALL T cells by anion-exchange chromatography followed by immunoprecipitation with the UN1 mAb and MALDI-TOF MS analysis. This analysis should assist in identifying the amino acid sequence of UN