827 research outputs found
The 1:1 resonance in Extrasolar Systems: Migration from planetary to satellite orbits
We present families of symmetric and asymmetric periodic orbits at the 1/1
resonance, for a planetary system consisting of a star and two small bodies, in
comparison to the star, moving in the same plane under their mutual
gravitational attraction. The stable 1/1 resonant periodic orbits belong to a
family which has a planetary branch, with the two planets moving in nearly
Keplerian orbits with non zero eccentricities and a satellite branch, where the
gravitational interaction between the two planets dominates the attraction from
the star and the two planets form a close binary which revolves around the
star. The stability regions around periodic orbits along the family are
studied. Next, we study the dynamical evolution in time of a planetary system
with two planets which is initially trapped in a stable 1/1 resonant periodic
motion, when a drag force is included in the system. We prove that if we start
with a 1/1 resonant planetary system with large eccentricities, the system
migrates, due to the drag force, {\it along the family of periodic orbits} and
is finally trapped in a satellite orbit. This, in principle, provides a
mechanism for the generation of a satellite system: we start with a planetary
system and the final stage is a system where the two small bodies form a close
binary whose center of mass revolves around the star.Comment: to appear in Cel.Mech.Dyn.Ast
Embedding Collective Ownership into a Systems Migration
The efforts presented here aim to humanize and honor the employees impacted by systems migrations. The authors hope that this can help other libraries interested in doing likewise. The official abstract is as follows:
Armacost Library at the University of Redlands structured the experience of an integrated library system migration to encourage agency, collaboration, and user-centeredness. Careful deliberation by library leadership and creative team-building activities enabled the library to address technological, cultural, and patron-facing changes wrought by the migration. The presenters related migration leadership to the NASIG Core Competencies for Electronic Resource Librarians and considered attributes needed to support colleagues in developing collective ownership
COBOL systems migration to SOA: Assessing antipatterns and complexity
SOA and Web Services allow users to easily expose business functions to build larger distributed systems. However, legacy systems - mostly in COBOL - are left aside unless applying a migration approach. The main approaches are direct and indirect migration. The former implies wrapping COBOL programs with a thin layer of a Web Service oriented language/platform. The latter needs reengineering COBOL functions to a modern language/ platform. In our previous work, we presented an intermediate approach based on direct migration where developed Web Services are later refactored to improve the quality of their interfaces. Refactorings mainly capture good practices inherent to indirect migration. For this, antipatterns for WSDL documents (common bad practices) are detected to prevent issues related to WSDLs understanding and discoverability. In this paper, we assess antipatterns of Web Services’ WSDL documents generated upon the three migration approaches. In addition, generated Web Services’ interfaces are measured in complexity to attend both comprehension and interoperability. We apply a metric suite (by Baski & Misra) to measure complexity on services interfaces - i.e., WSDL documents. Migrations of two real COBOL systems upon the three approaches were assessed on antipatterns evidences and the complexity level of the generated SOA frontiers - a total of 431 WSDL documents.Fil: Mateos Diaz, Cristian Maximiliano. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Tandil. Instituto Superior de IngenierĂa del Software. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto Superior de IngenierĂa del Software; ArgentinaFil: Zunino Suarez, Alejandro Octavio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Tandil. Instituto Superior de IngenierĂa del Software. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto Superior de IngenierĂa del Software; ArgentinaFil: Flores, AndrĂ©s Pablo. Universidad Nacional del Comahue. Facultad de Informática. Departamento IngenierĂa de Sistemas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Patagonia Norte; ArgentinaFil: Misra, Sanjay. Atilim University; TurquĂa. Covenant University; Nigeri
Security aspects of e-health systems migration to the cloud
As adoption of e-health solutions advances, new computing paradigms - such as cloud computing - bring the potential to improve efficiency in managing medical health records and help reduce costs. However, these opportunities introduce new security risks which can not be ignored. Based on our experience with deploying part of the Swedish electronic health records management system in an infrastructure cloud, we make an overview of major requirements that must be considered when migrating e-health systems to the cloud. Furthermore, we describe in-depth a new attack vector inherent to cloud deployments and present a novel data confidentiality and integrity protection mechanism for infrastructure clouds. This contribution aims to encourage exchange of best practices and lessons learned in migrating public e-health systems to the cloud
COBOL to Java and Newspapers Still Get Delivered
This paper is an experience report on migrating an American newspaper
company's business-critical IBM mainframe application to Linux servers by
automatically translating the application's source code from COBOL to Java and
converting the mainframe data store from VSAM KSDS files to an Oracle
relational database. The mainframe application had supported daily home
delivery of the newspaper since 1979. It was in need of modernization in order
to increase interoperability and enable future convergence with newer
enterprise systems as well as to reduce operating costs. Testing the modernized
application proved to be the most vexing area of work. This paper explains the
process that was employed to test functional equivalence between the legacy and
modernized applications, the main testing challenges, and lessons learned after
having operated and maintained the modernized application in production over
the last eight months. The goal of delivering a functionally equivalent system
was achieved, but problems remained to be solved related to new feature
development, business domain knowledge transfer, and recruiting new software
engineers to work on the modernized application.Comment: 4 pages, Accepted to be Published in: Proceedings of the 2018 IEEE
International Conference on Software Maintenance and Evolution (ICSME),
September 23-29, 2018, Madrid, Spai
CO2 Storage Capacity Assessment of Aquifers in South Africa
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The long noncoding RNA, treRNA, decreases DNA damage and is associated with poor response to chemotherapy in chronic lymphocytic leukemia.
The study of long noncoding RNAs (lncRNAs) is an emerging area of cancer research, in part due to their ability to serve as disease biomarkers. However, few studies have investigated lncRNAs in chronic lymphocytic leukemia (CLL). We have identified one particular lncRNA, treRNA, which is overexpressed in CLL B-cells. We measured transcript expression in 144 CLL patient samples and separated samples into high or low expression of treRNA relative to the overall median. We found that high expression of treRNA is significantly associated with shorter time to treatment. High treRNA also correlates with poor prognostic indicators such as unmutated IGHV and high ZAP70 protein expression. We validated these initial findings in samples collected in a clinical trial comparing the nucleoside analog fludarabine alone or in combination with the alkylating agent cyclophosphamide in untreated CLL samples collected prior to starting therapy (E2997). High expression of treRNA was independently prognostic for shorter progression free survival in patients receiving fludarabine plus cyclophosphamide. Given these results, in order to study the role of treRNA in DNA damage response we generated a model cell line system where treRNA was over-expressed in the human B-CLL cell line OSU-CLL. Relative to the vector control line, there was less cell death in OSU-CLL over-expressing treRNA after exposure to fludarabine and mafosfamide, due in part to a reduction in DNA damage. Therefore, we suggest that treRNA is a novel biomarker in CLL associated with aggressive disease and poor response to chemotherapy through enhanced protection against cytotoxic mediated DNA damage
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