Social influence in the adoption of a B2B loyalty program: The role of elite status members

This study investigates the role of elite loyalty program members in influencing other customers to adopt a hierarchical loyalty program (or HLP) in a business market. Drawing from the social psychology literature, the theoretical framework proposes that elite status members exert a disproportionate positive influence on neighboring non-members to adopt the HLP, and that this social influence has an inverse U-shaped effect. A unique dataset from a B2B loyalty program of a firm in the agribusiness industry with detailed information on members and marketing efforts from 1378 zip codes in Germany from 2008 to 2012 is used for the analysis. The study finds that, compared to members in lower status, elite status members have a stronger social influence on non-members. Importantly, as the proportion of elite status members increases, the adoption probability of non-members increases. However, as the fraction of elite status members increases beyond a certain point, the adoption probability of non-members decreases. Overall, the results of this study advances our understanding of loyalty programs in B2B markets, particularly with regard to the drivers of loyalty program adoption and the role played by social influence in driving new member enrollment

Direct observation of melting in a 2-D superconducting vortex lattice

Topological defects such as dislocations and disclinations are predicted to determine the twodimensional (2-D) melting transition. In 2-D superconducting vortex lattices, macroscopic measurements evidence melting close to the transition to the normal state. However, the direct observation at the scale of individual vortices of the melting sequence has never been performed. Here we provide step by step imaging through scanning tunneling spectroscopy of a 2-D system of vortices up to the melting transition in a focused-ion-beam nanodeposited W-based superconducting thin film. We show directly the transition into an isotropic liquid below the superconducting critical temperature. Before that, we find a hexatic phase, characterized by the appearance of free dislocations, and a smectic-like phase, possibly originated through partial disclination unbinding. These results represent a significant step in the understanding of melting of 2-D systems, with impact across several research fields, such as liquid crystal molecules, or lipids in membranes.Comment: Submitted to Nature Physic

Quantifying the effect of status in a multi-tier loyalty program

Multi-Tier Loyalty Programs (MTLPs) have become a popular marketing instrument to develop customer-firm relationships. Within a MTLP, customers are assigned to different tiers based on their purchase behavior. In this article, we examine whether and when tiers in the MTLP are effective in influencing customer purchase behavior, specifically share of wallet (SOW). A unique business-to-business dataset of a firm in the German agricultural market from 2009 to 2017 is used for the analysis. Data is available on the customer-specific tier level in the MTLP each year. We utilize a Tobit-style panel regression model for the analysis which is inspired by the Regression Discontinuity Design approach. This study makes several important contributions. First, it examines the effect of status in MTLPs and uses causal design to quantify the hitherto intangible effect of customer tiers. Second, this study reveals important insights on how the tier levels interact with other drivers of customer-firm relationships. Third, we use an interesting dataset from a B2B market and thereby contribute to the limited existing literature on the effectiveness of loyalty programs in B2B markets. Armed with a new understanding of how customers respond to tier levels or the negative effects of tenure especially in the highest tier, academics and managers gain new perspectives of whether and how loyalty programs affect customer behavior and drive desired outcomes in the marketplace. © 202

Enhancement of long range correlations in a 2D vortex lattice by incommensurate 1D disorder potential

Long range correlations in two-dimensional (2D) systems are significantly altered by disorder potentials. Theory has predicted the existence of disorder induced phenomena such as Anderson localization and the emergence of novel glass and insulating phases as the Bose glass. More recently, it has been shown that disorder breaking the 2D continuous symmetry, such as a one dimensional (1D) modulation, can enhance long range correlations. Experimentally, developments in quantum gases have allowed the observation of a wealth of phenomena induced by the competition between interaction and disorder. However, there are no experiments exploring the effect of symmetry-breaking disorder. Here, we create a 2D vortex lattice at 0.1 K in a superconducting thin film with a well-defined 1D thickness modulation and track the field induced modification using scanning tunneling microscopy. We find that the 1D modulation becomes incommensurate to the vortex lattice and drives an order-disorder transition, behaving as a scale-invariant disorder potential. We show that the transition occurs in two steps and is mediated by the proliferation of topological defects. We find that critical exponents determining the loss of positional and orientational order are far above theoretical expectations for scale-invariant disorder and follow instead the critical behaviour which describes dislocation unbinding melting. Our data show for the first time that randomness disorders a 2D crystal, and evidence enhanced long range correlations in presence of a 1D modulation demonstrating the transformation induced by symmetry breaking disorder in interactions and the critical behaviour of the transition.Comment: 7 pages, 3 figures and supplementary information (11 pages, 9 figures

Screen-printed nanoparticles as anti-counterfeiting tags

Metallic nanoparticles with different physical properties have been screen printed as authentication tags on different types of paper. Gold and silver nanoparticles show unique optical signatures, including sharp emission bandwidths and long lifetimes of the printed label, even under accelerated weathering conditions. Magnetic nanoparticles show distinct physical signals that depend on the size of the nanoparticle itself. They were also screen printed on different substrates and their magnetic signals read out using a magnetic pattern recognition sensor and a vibrating sample magnetometer. The novelty of our work lies in the demonstration that the combination of nanomaterials with optical and magnetic properties on the same printed support is possible, and the resulting combined signals can be used to obtain a user-configurable label, providing a high degree of security in anti-counterfeiting applications using simple commercially-available sensors

Agromorphological genetic diversity of Spanish traditional melons

[EN] The variability of 62 Spanish landraces (and two hybrids used as reference) was described by analysing 39 morphological traits and eight SSR makers. Results showed that 81% of the examined genetic pool belonged to the inodorus type. Spanish traditional melons presented fruits from flattened and globular shapes to elliptical. Rind colour varied from pale green, almost white and yellow to dark green and almost black. Rind texture varied from smooth to intensely wrinkled. Spanish landraces also had larger fruits (average fruit weight 2.6 kg) and longer vegetative cycles (117 days to maturity) compared to landraces from other geographical origins. Farmers seem to have focused on selection towards large fruits, which usually requires the longest production cycles. Fruit colour, size and shape seemed to have been determinant in varietal selection. Hierarchical clustering resulted in two main groups (climacteric and non-climacteric). The largest group was composed of 60 accessions of non-climacteric types, which includes the most demanded by national markets, 'Piel de Sapo', which fruits were characterized by an ovate or elliptical shape, a green rind, big spots and stains distributed over the whole fruit, a rounded blossom end shape and a very pointed stem end shape. The study demonstrates that the Spanish genetic pool is much more diverse. Wide variability was found in a geographical area with vast historical importance in melon farming. These evaluations has allowed the identification of several uniform groups of non-climacteric cultivars ('Piel de Sapo', 'Mochuelo', 'Tendral', Yellow/White, Winter and Black groups) and a set of highly variable climacteric ones. However, many accessions with singular properties remain unclassified, demonstrating the morphological variability of the studied collection. Melons in Spain have wide variability together with a vast historical importance on farms. Some fruit types, or at least some morphological characters reflected by painters during centuries, have reached the present. The present study confirmed the need to preserve these irreplaceable genetic resources and continue their study and evaluation for valuable traits which could enhance farmer's opportunities for entering new markets.The authors would like to thank Maria Jose Diez, the curator of the COMAV's Genebank for providing some of the melon varieties included in this study. Financial support was received from the Genome-Spain Foundation through the Project MELONOMICS (http://www.gen-es.org/es/melanomics.cfm). This study was partially supported by the Project AGL2014-53398-C2-R (funded by the Spanish Economy and Competitiveness Department, and the European Regional Development Fund).Lázaro, A.; Fernandez, I.; Borrero, M.; Cabello, F.; Lopez-Sese, A.; Gómez-Guillamon, M.; Picó Sirvent, MB. (2017). Agromorphological genetic diversity of Spanish traditional melons. 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IMIDRA, Madrid, ISBN-10: 84-695-6262-2. www.madrid.org/bvirtual/BVCM003438.pdfLázaro A, Fernández-Navarro I, de Lorenzo C (2016) Using landraces in agriculture, food and cooking: experiences around a big city in Southern Europe. In: Maxted N, Dulloo MF-LB (eds) Enhancing crop genepool use. CABI, Birmingham, pp 313–317Levene H (1949) On a matching problem arising in genetics. Ann Math Stat 20:91–94Lewontin RC (1972) The apportionment of human diversity. Evol Biol 6:381–398López-Sesé AI, Staub JE, Gómez-Guillamón ML (2003) Genetic analysis of Spanish melon (Cucumis melo L.) germplasm using a standardized molecular-marker array and geographically diverse reference accessions. Theor Appl Genet 108(1):41–52Lotti C, Marcotrigiano A, De Giovanni C, Resta P, Ricciardi A, Zonno V, Fanizza G, Ricciardi L (2008) Univariate and multivariate analysis performed on bio-agronomical traits of Cucumis melo L. germplasm. 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Disordered hyperuniformity in superconducting vortex lattices

The current carrying capability of type II superconductors under magnetic fields is determined to a large extent by the interaction of superconducting vortices with pinning centers. Vortices are arranged in lattices with varying degrees of disorder depending on the balance between the intervortex interactions and the pinning strength. We analyze here vortex arrangements in disordered vortex lattices of different superconducting systems, single crystals (Co-doped NbSe2, LiFeAs, and CaKFe4As4), and amorphous W- based thin films (with critical temperatures T-c from 4 K to 35 K and critical fields from 3.4 T to more than 90 T). We calculate for each case the structure factor and number variance and compare to calculations on an interacting set of partially pinned particles. We find that random density fluctuations appear when pinning overcomes interactions and show that the suppression of density fluctuations is correlated to the presence of interactions. We discuss the results within the framework of hyperuniform distributions and find that all studied lattices follow a similar increase of the number variance with the defect density

Association of body composition indices with insulin resistance in European adolescents: The HELENA study

Background: The different body components may contribute to the development of insulin resistance and type 2 diabetes mellitus. The aim of the present study was to examine the association of fat mass and fat free mass indices with markers of insulin resistance, independently of each other and giving, at the same time, gender-specific information in a wide cohort of European adolescents. Methods: A cross-sectional study in a school setting was conducted in 925 (430 males) adolescents (14.9 ± 1.2 years). Weight, height, anthropometric, bioimpedance and blood parameters were measured. Indices for fat mass and fat free mass, and homeostatic model assessment (HOMA) were calculated. Multiple regression analyses were performed adjusting for several confounders including fat free mass and fat mass when possible. Results: Indices of fat mass were positively associated with HOMA (all p < 0.01) after adjusting for all the confounders including fat free mass indices, in both sexes. Fat free mass indices were associated with HOMA, in both males and females, after adjusting for center, pubertal status, socioeconomic status and cardiorespiratory fitness, but the associations disappear when including fat mass indices in the adjustment’s model. Conclusion: Fat mass indices derived from different methods are positively associated with insulin resistance independently of several confounders including fat free mass indices. In addition, the relationship of fat free mass with insulin resistance is influenced by the amount of fat mass in European adolescents. Nevertheless, future studies should focus not only on the role of fat mass, but also on other body components such as fat free mass because its role could vary depending of the level and distribution of fat mass