287 research outputs found
ANALYSIS OF SMALL BUSINESS PARTICIPATION IN ONLINE MARKETPLACES
As commercial e-commerce portals continue to grow in popularity among the acquisition workforce, it is imperative that the federal government ensures companies of all business sizes are able to compete fairly. This research examines the current framework of platform providers and makes recommendations on how small businesses can be better utilized without sacrificing competition, while keeping an extensive industry base and receiving best value for both the taxpayer and warfighter.Civilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited
Vacancy Tuning in Li,V-Substituted Lyonsites
© 2020 Taylor & Francis Group, LLC. The lyonsite structure, characterized by the formula A 4 M 3O12, is a relatively understudied tunneled crystal structure. This host structure is known to be compositionally flexible, able to incorporate a number of cations in various oxidation states into the A site. In the parent compound Co3.75V1.5Mo1.5O12, it is apparent that a stoichiometric vacancy of 0.25 is unavoidable as a result of Coulombic repulsion. This work focuses on the systematic elimination of vacancies by chemically introducing guest Li ions while maintaining host integrity. A full solid solution was found to exist with the formula □0.25–1/8xLi x Co3.75–7/8xV1.5–3/4xMo1.5+3/4xO12 (0 ≤ x ≤ 2), terminating at the known end member Li2Co2Mo3O12. Lattice refinements on PXRD data confirmed the isostructural nature of the whole series, and detailed structural analysis revealed that competition between Li and Co in the same crystallographic site is unequal, with Li exhibiting a stronger site preference for larger interstitial sites. Diffuse reflectance analysis revealed that the optical band gap is directly tunable with x, and supporting structure-property relationships were also explored via magnetometry and dielectric measurements
Leggett Modes Accompanying Crystallographic Phase Transitions
Higgs and Goldstone modes, well known in high-energy physics, have been realized in a number of condensed matter physics contexts, including superconductivity and magnetism. The Goldstone-Higgs concept is also applicable to and gives rise to new insight on structural phase transitions. Here, we show that the Leggett mode, a collective mode observed in multiband superconductors, also has an analog in crystallographic phase transitions. Such structural Leggett modes can occur in the phase channel as in the original work of Leggett [Prog. Theor. Phys. 36, 901 (1966)PTPKAV0033-068X10.1143/PTP.36.901]. That is, they are antiphase Goldstone modes (antiphasons). In addition, a new collective mode can also occur in the amplitude channel, an out-of phase (antiphase) Higgs mode, that should be observable in multiband superconductors as well. We illustrate the existence and properties of these structural Leggett modes using the example of the pyrochlore relaxor ferroelectric Cd2Nb2O7
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Genome-wide Functional Analysis of CREB/Long-Term Memory-Dependent Transcription Reveals Distinct Basal and Memory Gene Expression Programs
SummaryInduced CREB activity is a hallmark of long-term memory, but the full repertoire of CREB transcriptional targets required specifically for memory is not known in any system. To obtain a more complete picture of the mechanisms involved in memory, we combined memory training with genome-wide transcriptional analysis of C. elegans CREB mutants. This approach identified 757 significant CREB/memory-induced targets and confirmed the involvement of known memory genes from other organisms, but also suggested new mechanisms and novel components that may be conserved through mammals. CREB mediates distinct basal and memory transcriptional programs at least partially through spatial restriction of CREB activity: basal targets are regulated primarily in nonneuronal tissues, while memory targets are enriched for neuronal expression, emanating from CREB activity in AIM neurons. This suite of novel memory-associated genes will provide a platform for the discovery of orthologous mammalian long-term memory components
PRECISE SEMI-AUTOMATIC FIELD MAPPING IN THE SPLIT FIELD MAGNET OF THE ISR
Abstract The computer-controlled equipment for the magnetic measurements of the Split Field Magnet System of the CERN Intersecting Storage Rings is described. Three different measurement machines are necessary for the measurements of this large and complex magnet system. The strongly inhomogeneous field is measured to a precision of 1 0/00 of maximum field using Hall-plate assemblies. The final data treatment includes the smoothing out of the established scalar potential by solving the Laplace's equation from the conditions at the boundaries by means of relaxation. The threedimensional field map will be used for particle analysis. Effects of the SFM-field on the circulating ISR beams are evaluated and optimized
The Reintegration of Ex-Combatants and Post-Conflict Violence. An Analysis of Municipal Crime Levels in Colombia
Violent crime in Colombia is analyzed following the demobilization of ex-combatants using municipal-level data. The main findings are that an increased presence of ex-combatants does not systematically increase homicides, but may increase robberies. Reintegration programs are shown to matter. Former paramilitaries who are not in a reintegration program increase crime. Former guerillas increase robberies, regardless of whether they are in or out of reintegration, but homicides decrease for guerrillas in reintegration. Ex-combatants often settle in municipalities with more crime. Controlling for reverse causality, ex-combatants only increase crime if they are not in reintegration, while in reintegration they may reduce crime
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The masculine logic of DDR and SSR in the Rwanda Defence Force
Since the 1994 genocide and civil war, the Rwandan government has implemented an externally funded Demobilisation, Demilitarisation and Reintegration (DDR)/Security Sector Reform (SSR) program culminating in the consolidation of armed groups into a new, professionalised Rwanda Defence Force (RDF). Feminists argue that DDR-SSR initiatives that exclude combatant women and girls or ignore gendered security needs fail to transform the political conditions that led to conflict. Less attention has been paid to how gendered relations of power play out through gender sensitive DDR and SSR initiatives that seek to integrate women and transform hyper-masculine militarised masculinities. This article investigates how Rwanda’s DDR-SSR program is governed by an oppressive masculine logic. Drawing on critical studies on men and masculinities and feminist work on peacebuilding, myths and the politics of belonging, it is argued that Rwanda’s locally-owned DDR-SSR program places the military and militarisation at the centre of the nation-building program. Through various ‘boundary construction’ practices, the Rwandan government attempts to stabilise the post-1994 gender order and entrench the hegemony of a new militarised masculinity in Rwandan society. The case study draws on field research conducted in 2014 and 2015 and a discourse analysis of RDF historical accounts, policy documents and training materials
THE LHC POST MORTEM ANALYSIS FRAMEWORK
Abstract The LHC with its unprecedented complexity and criticality of beam operation will need thorough analysis of data taken from systems such as power converters, interlocks and beam instrumentation during events like magnet quenches and beam loss. The causes of beam aborts or in the worst case equipment damage have to be revealed to improve operational procedures and protection systems. The correct functioning of the protection systems with their required redundancy has to be verified after each such event. Post mortem analysis software for the control room has been prepared with automated analysis packages in view of the large number of systems and data volume. This paper recalls the requirements for the LHC Beam Post Mortem System (PM) and the necessity for highly reliable data collection. It describes in detail the redundant architecture for data collection as well as the chosen implementation of a multi-level analysis framework, allowing for automated analysis and qualification of a beam dump event based on expert provided analysis modules. It concludes with an example of the data taken during first beam tests in September 2008 with a first version of the system
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