On the production of heavy axion-like particles in the accretion disks of gamma-ray bursts

Heavy axion-like particles have been introduced in several scenarios beyond the Standard Model and their production in some astrophysical systems should be possible. In this work, we re-examine the possibility that these type of particles can be generated in the accretion disks of gamma-ray bursts (GRB), the most powerful events in the universe. If the produced axions decay into photons or $e^+e-$ pairs at the correct distances, a fireball is generated. We calculate the structure transient accretion disks in GRBs (density, temperature and thickness profiles) taking into account the effect of heavy axion emission as well as the rest of the relevant standard cooling processes. This allows us to obtain the values of the coupling constant g_{aN} in order for the axions not to become trapped, and we can also compute the emitted heavy axion luminosity from the entire disk. We find that for the couplings within the ranges found, then the mechanism for powering GRBs based on heavy axion production and decay becomes an alternative to the standard picture based upon magnetohydrodynamic processes and neutrino-antineutrino annihilation. Otherwise, if heavy axions are produced in the disk but their decay to takes place further away, the mechanism fails. Still, the decay products (gamma rays or electrons and positrons) should leave observable signatures which are not observed for different ranges of values of the coupling constants, depending on the mass of the heavy axionComment: 14 pages, 7 figures. Updated version that matches the one to be published on Physics Letters

Using cross-functional, cross-firm teams to co-create value: The role of financial measures

Increasingly, the involvement of representatives from all major business functions in cross-functional, crossfirmteams is being viewed as a means to develop and maintain profitable business-to-business relationships.However, if the measurements of the value co-created in these relationships with customers and suppliers donot incorporate the financial outcomes of joint cross-functional initiatives, managers can be led to makedecisions that jeopardize the long-term profitability of the two firms. In this paper, the authors explore thedifferences in value co-creation when a company is linked to key customers and key suppliers through crossfunctionalteams and when it is not. Using a case study approach, the authors measured value co-creation infinancial terms and describe how managers changed their behaviors toward customers and suppliers whenthey were able to compare the value that was being co-created in each relationship. In each pair ofrelationships, one involved cross-functional teams and the other did not. The results indicate that crossfunctional,cross-firm involvement leads to increased value co-creation. The research suggests that marketingscholars and managers should emphasize the use of cross-functional teams that involve all major functions tomanage relationships with key customers, and should incorporate financial measures in the evaluation ofrelationship performance

Lensing Induced Cluster Signatures in Cosmic Microwave Background

We show that clusters of galaxies induce step-like wiggles on top of the cosmic microwave background (CMB). The direction of the wiggle is parallel to the large scale gradient of CMB allowing one to isolate the effect from other small scale fluctuations. The effect is sensitive to the deflection angle rather than its derivative (shear or magnification) and is thus tracing outer parts of the cluster with higher sensitivity than some other methods. A typical amplitude of the effect is $10\mu K (\sigma_v/1400 kms^{-1})^2$ where $\sigma_v$ is the velocity dispersion of the cluster and several $\mu K$ signals extend out to a fraction of a degree. We derive the expressions for the temperature profile for several simple parameterized cluster models and identify some degeneracies between parameters. Finally, we discuss how to separate this signal from other imprints on CMB using custom designed filters. Detection of this effect is within reach of the next generation of small scale CMB telescopes and could provide information about the cluster density profile beyond the virial radius.Comment: 10 pages, 3 figures, submitted to Ap

Adopting New Zealand Dairy Farm Principles and Practices in Argentina

The dairy sector is important to Argentina because it creates genuine wealth and employment. Milk production at competitive costs is crucial for the endurance of the Argentine dairy sector; therefore the development of competitive dairy farm systems is important for Argentina. New Zealand (hereafter NZ) dairy farm systems are internationally known for their competitiveness without the presence of subsidies. Though Argentine dairy farmers have been attracted to NZ systems for more than 40 years and despite the fact that the NZ knowledge appears to be beneficial to Argentine farms, NZ practices have been rarely adopted. This seemingly fruitless effort in extending this technology shapes the research question of the present study: Can Argentine dairy farmers benefit from adopting New Zealand dairy farm principles and practices? Seven Argentine dairy farmers were selected as case studies because of their awareness of NZ dairy systems; the research data was collected through interviews, farm physical and economic records, and field visits to the farms. Two frameworks were utilized to analyse the qualitative and quantitative data: the Diffusion Theory (Rogers, 2003) and the IFCN network (International Farm Comparison Network www.ifcnnetwork.org), respectively. Ten NZ innovations were defined; they were principles and practices considered typical in NZ dairy farms and not common in Argentine dairy farms. The innovations were related to four areas of the dairy system: pasture management, herd management & genetics, farm structure & organization, and human resources. The seven farmers selected differed in the level of adoption or rejection of the innovations. Results revealed that higher levels of adoption of NZ innovations by a group of Argentine dairy farms were associated with higher levels of Return on Investment; this was mainly due to a higher utilization of the main asset and most limiting production factor of Argentine and New Zealand dairy farms, the land.Argentine dairy farm systems, New Zealand innovations for Argentina, Argentine dairy industry, Argentine dairy systems, diffusion of innovations, adoption of innovations, Livestock Production/Industries,

The interplay between habitat structure and chemical contaminants on biotic responses of benthic organisms

Habitat structure influences the diversity and distribution of organisms, potentially affecting their response to disturbances by either affecting their ‘susceptibility’ or through the provision of resources that can mitigate impacts of disturbances. Chemical disturbances due to contamination are associated with decreases in diversity and functioning of systems and are also likely to increase due to coastal urbanisation. Understanding how habitat structure interacts with contaminants is essential to predict and therefore manage such effects, minimising their consequences to marine systems. Here, we manipulated two structurally different habitats and exposed them to different types of contaminants. The effects of contamination and habitat structure interacted, affecting species richness. More complex experimental habitats were colonized by a greater diversity of organisms than the less complex habitats. These differences disappeared, however, when habitats were exposed to contaminants, suggesting that contaminants can override effects of habitats structure at small spatial scales. These results provide insight into the complex ways that habitat structure and contamination interact and the need to incorporate evidence of biotic responses from individual disturbances to multiple stressors. Such effects need to be taken into account when designing and planning management and conservation strategies to natural systems