Eikonal zeros in the momentum transfer space from proton-proton scattering: An empirical analysis

By means of improved empirical fits to the differential cross section data on $pp$ elastic scattering at $19.4 \le\sqrt{s}\le 62.5$ GeV and making use of a semi-analytical method, we determine the eikonal in the momentum transfer space (the inverse scattering problem). This method allows the propagation of the uncertainties from the fit parameters up to the extracted eikonal, providing statistical evidence that the imaginary part of the eikonal (real part of the opacity function) presents a zero (change of signal) in the momentum space, at $q^2 \approx 7 \pm 1$ GeV$^2$. We discuss the implication of this change of signal in the phenomenological context, showing that eikonal models with one zero provide good descriptions of the differential cross sections in the full momentum transfer range, but that is not the case for models without zero. Empirical connections between the extracted eikonal and results from a recent global analysis on the proton electric form factor are also discussed, in special the Wu-Yang conjecture. In addition, we present a critical review on the $pp$ differential cross section data presently available at high energies.Comment: Two references and some misprints corrected, 22 pages; final version to be published in Eur.Phys. J. C (2008

First record of the Mediterranean asteroid Sclerasterias richardi (Perrier in Milne-Edwards 1882) in the Azores Archipelago (NE Atlantic Ocean)

The first occurrence of the Mediterranean fissiparous asteroid Sclerasterias richardi (Perrier in Milne-Edwards 1882) is reported from the Azores based upon dredged material off the south coast of São Miguel Island at 135 m depth. This record represents a considerable expansion of the species’ geographic range, otherwise reported with certainty only from the Mediterranean Sea. S. richardi is capable of producing long-lived planktotrophic larvae with high dispersal potential to reach remote areas such as the Azores. Alternatively, this species is also capable of reproducing asexually through fission, which could insure the maintenance of viable numbers in a stranded population. The presence of S. richardi in Azorean waters and its rarity in an otherwise thoroughly investigated area does not necessarily imply a recent arrival nor a human-mediated introduction, as the depths in consideration (80-700 m) are also the least studied in the archipelago.info:eu-repo/semantics/publishedVersio

Effect of user experience on technology acceptance: the case of foss

Free and open source software (FOSS) movement essentially arises like answer to the evolution occurred in the market from the software, characterized by the closing of the source code. Furthermore, some FOSS characteristics, such as (1) the advance of this movement and (2) the attractiveness that contributes the voluntary and cooperative work, have increased the interest of the users towards free software. Traditionally, research in FOSS has focused on identifying individual personal motives for participating in the development of a FOSS project, analyzing specific FOSS solutions, or the FOSS movement itself. Nevertheless, the advantages of the FOSS for users and the effect of the demographic dimensions on user acceptance for FOSS have been two research topics with little attention. Specifically, this paper’s aim is to focus on the influence of the user experience with FOSS the FOSS acceptance. Based on the literature, user experience is an essential demographic dimension for explaining the Information Systems acceptance. With this purpose, the authors have developed a research model based on the Technological Acceptance Model (TAM).El movimiento asociado al software de código abierto (FOSS) surge como una respuesta a la evolución acontecida en el mercado del software, caracterizado por el cierre del código fuente. Además, algunas características del FOSS como (1) el avance de este movimiento y (2) el atractivo que suscita debido a que se construye bajo la filosofía de trabajo voluntario y cooperativo, ha incrementado el interés de los usuarios hacia FOSS. Tradicionalmente las investigaciones en FOSS han estado centradas en identificar las motivaciones personales de participar en el desarrollo de un proyecto FOSS. Mientras que las ventajas del FOSS para los usuarios y el efecto de las dimensiones demográficas en la aceptación de FOSS han sido dos tópicos de investigación con poca atención. Concretamente, este artículo se centra en analizar la influencia de la experiencia con FOSS en la propia aceptación de FOSS. Basado en la literatura, la experiencia del usuario es una dimensión demográfica esencial para explicar la aceptación de los Sistemas de Información. Con este propósito, los autores han desarrollado un modelo de investigación basado en el Metamodelo de Aceptación de la Tecnología (TAM)

User acceptance of open enterprise solution: the OSS-ERP case

Organizations implement Enterprise Resource Planning (ERP) systems with the objective of reaching operational efficiency and the incorporation to new markets through the information flow control on time of the entire organization. However, ERP systems are complex tools, mainly for the small and medium size enterprises (SMEs). For these reason, new ERP configurations have arisen for SMEs such as Open Source Software-ERP (OSS-ERP). OSS-ERP is a research topic barely analyzed by the literature. Specifically, this paper’s aim is to focus on the OSS-ERP users’ acceptance and use. The authors have developed a research model based on the Technology Acceptance Model (TAM) for testing the users’ behavior toward OSS-ERP.Las organizaciones implantan Sistemas Integrados de Gestión (ERP, acrónimo de Enterprise Resource Planning) con el objetivo de alcanzar eficiencias operativas y la incorporación a nuevos mercados mediante un mayor control del flujo de información de toda la empresa a tiempo real. Sin embargo, los sistemas ERP son herramientas complejas, principalmente la pequeña y mediana empresa (PYME). Por esta razón, están surgiendo nuevas configuraciones de sistemas ERP para PYME como los sistemas ERP de código abierto (OSS-ERP). OSS-ERP es un tópico de investigación escasamente analizado en la literatura. Concretamente, este artículo se centra en el y aceptación de los usuarios a los sistemas OSS-ERP. Los autores han desarrollado un modelo de investigación basado en Metamodelo de Aceptación de la Tecnología (TAM) para testar el comportamiento de los usuarios hacia los sistemas OSS-ERP