23,402 research outputs found
Computer-controlled vibration testing
System features quickly achieved steady state, increased accuracy of spectrum definition, and true Gaussian amplitude distribution of resulting signals. Controlled shock-tests might also be tried with this system
Imaging ionospheric inhomogeneities using spaceborne synthetic aperture radar
We present a technique and results of 2-D imaging of Faraday rotation and total electron content using spaceborne L band polarimetric synthetic aperture radar (PolSAR). The results are obtained by processing PolSAR data collected using the Phased Array type L-band Synthetic Aperture Radar (PALSAR) on board the Advanced Land Observation Satellite. Distinguished ionospheric inhomogeneities are captured in 2-D images from space with relatively high resolutions of hundreds of meters to a couple of kilometers in auroral-, middle-, and low-latitude regions. The observed phenomena include aurora-associated ionospheric enhancement arcs, the middle-latitude trough, traveling ionospheric disturbances, and plasma bubbles, as well as ionospheric irregularities. These demonstrate a new capability of spaceborne synthetic aperture radar that will not only provide measurements to correction of ionospheric effects in Earth science imagery but also significantly benefit ionospheric studies
IT governance as a higher order capability
This paper utilises the resource-based view as a framework to examine the interactions between information technology (IT) governance, IT management and organisational information systems. Analysis of data collected from medium and large Australian organisations indicates that IT governance capabilities act to improve IT management capabilities which in turn improve the performance of organisational information systems, specifically future-oriented accounting information systems. We propose that these interactions represent the operation of an overarching organisational IT capability. Further analysis finds significant differences in the most effective combinations of IT governance and IT management mechanisms for organisations facing differing levels of environmental turbulence. This finding highlights the importance of utilising IT governance as a higher order organisational capability to reconfigure and align capabilities and resources in response to changing strategic requirements and environmental pressures
The genetics of symbiotic nitrogen fixation: comparative genomics of 14 Rhizobia Strains by resolution of protein clusters.
The symbiotic relationship between legumes and nitrogen fixing bacteria is critical for agriculture, as it may have profound impacts on lowering costs for farmers, on land sustainability, on soil quality, and on mitigation of greenhouse gas emissions. However, despite the importance of the symbioses to the global nitrogen cycling balance, very few rhizobial genomes have been sequenced so far, although there are some ongoing efforts in sequencing elite strains. In this study, the genomes of fourteen selected strains of the order Rhizobiales, all previously fully sequenced and annotated, were compared to assess differences between the strains and to investigate the feasibility of defining a core ?symbiome??the essential genes required by all rhizobia for nodulation and nitrogen fixation. Comparison of these whole genomes has revealed valuable information, such as several events of lateral gene transfer, particularly in the symbiotic plasmids and genomic islands that have contributed to a better understanding of the evolution of contrasting symbioses. Unique genes were also identified, as well as omissions of symbiotic genes that were expected to be found. Protein comparisons have also allowed the identification of a variety of similarities and differences in several groups of genes, including those involved in nodulation, nitrogen fixation, production of exopolysaccharides, Type I to Type VI secretion systems, among others, and identifying some key genes that could be related to host specificity and/or a better saprophytic ability. However, while several significant differences in the type and number of proteins were observed, the evidence presented suggests no simple core symbiome exists. A more abstract systems biology concept of nitrogen fixing symbiosis may be required. The results have also highlighted that comparative genomics represents a valuable tool for capturing specificities and generalities of each genome.bitstream/item/74069/1/ID-34062.pd
Management Accounting Functionality in SAP Solutions â Implications for Research and Practise
Since the start of the new millennium, management accounting researchers have investigated how Enterprise Resource Planning systems (ERPS) or the implementation of such systems influences management accounting (practises) and/or firm performance. More recently, the empirical focus of such studies has shifted towards the SAP ERPS, the world-market leading enterprise system (Columbus, 2014). Despite this focus, none of these studies has ever described the management accounting functionalities of SAP ERP, let alone acknowledging that, over the past decade, SAP has substantially expanded its solution range for management accounting, in particular with the acquisition of BusinessObjects in 2007. Today, management accounting functionalities are dispersed across a wide range of SAP âsolutionsâ beyond the core SAP ERP, including cloud solutions, and even for SAP customers it is difficult to reconcile which software component contributes the various âsolution for management accountingâ. We argue that research on the impacts of such systems on management accounting practises and performance requires a detailed understanding of the management accounting functionality provided by such systems â across all modules and add-on components. Our archival and expert-interview based study aims to provide such insights by systematically analysing the current SAP software solutions range to locate management accounting tools and to map those tools with the broader body of knowledge of management accounting practises. Key findings of our study are that the SAP software range provides support for almost all common management accounting practises and that for some of these practises SAP users are provided with a range of tools providing similar functionality (e.g. SAP SEM, SAP Strategy Management, and SAP BusinessObjects Strategy Management). Further to that, the SAP software range provides management accounting functionalities such as âGrenzplankostenrechnungâ (GPK), which is a core element of the German tradition of âControllingâ (Becker and Messner 2005), and has so far only attracted limited attention in the international management accounting community. The SAP tools for management accounting are partly embedded in the standard SAP ERP package, but many of them come as complementary or supplementary extensions or as part of data warehouse based Business Intelligence components (incl. BusinessObjects components). Considering the large range of management accounting components and the many adoption options provided, we expect heterogeneity amongst SAP user organisations in terms of system support for management accounting. In stage two of the broader research project, we will conduct a field study to verify this prediction and investigate the implications for managerial decision making and performance management. We contribute to academic research by providing a systematic mapping of management accounting practises and the extensive SAP solutions range, thereby enabling researchers to conduct better informed empirical research in SAP environments. We also contribute to management accounting practise by deciphering marketing-driven SAP publications and mapping management accounting functionality with actual software components
Full characterisation of a focussed extreme ultraviolet beam using a non-redundant array of apertures
This paper presents a novel technique for characterising wavefront curvature and M2, by utilising a non-redundant array (NRA) of apertures to define the plane of investigation through an experimental extreme ultraviolet (EUV) focus. Appropriately sampled, far-field EUV scattering from this NRA is captured on a CCD as the NRA is scanned along the beam axis through the focus. By taking the inverse Fourier transform (IFT), it is possible obtain the spatial autocorrelation functions, via the Wiener-Khinchin theorem, of the exit wave field. By observing the position of the first-order peaks in the autocorrelation as a function of grid translation, both the real and imaginary parts of the complex beam parameter can be determined and the M2 calculated, yielding full characterisation of the embedded Gaussian. Since the periodicity of the grid is known, the planar pixel resolution can be calculated, also allowing the translations movement to be confirmed due to the change in angular acceptance of the fixed CCD. This makes the technique self-calibrating. A high impact, easy to use, cross field technique for full profiling of the embedded Gaussian of probe beams using a non-redundant array of apertures is presented. The technique is experimentally verified in the highly absorbing EUV spectral regime, and is expected to play a significant role in other regimes, where experimental issues prevent the use of existing techniques
A sandpile model with tokamak-like enhanced confinement phenomenology
Confinement phenomenology characteristic of magnetically confined plasmas
emerges naturally from a simple sandpile algorithm when the parameter
controlling redistribution scalelength is varied. Close analogues are found for
enhanced confinement, edge pedestals, and edge localised modes (ELMs), and for
the qualitative correlations between them. These results suggest that tokamak
observations of avalanching transport are deeply linked to the existence of
enhanced confinement and ELMs.Comment: Manuscript is revtex (latex) 1 file, 7 postscript figures Revised
version is final version accepted for publication in PRL Revisions are mino
The Redshift Distribution of the TOUGH Survey
We present the redshift results from a Very Large Telescope program aimed at
optimizing the legacy value of the Swift mission: to characterize a
homogeneous, X-ray selected, sample of 69 GRB host galaxies. 19 new redshifts
have been secured, resulting in a 83% (57/69) redshift completion, making the
survey the most comprehensive in terms of redshift completeness of any sample
to the full Swift depth, available to date. We present the cumulative redshift
distribution and derive a conservative, yet small, associated uncertainty. We
constrain the fraction of Swift GRBs at high redshift to a maximum of 10% (5%)
for z > 6 (z > 7). The mean redshift of the host sample is assessed to be >
2.2. Using this more complete sample, we confirm previous findings that the GRB
rate at high redshift (z > 3) appears to be in excess of predictions based on
assumptions that it should follow conventional determinations of the star
formation history of the universe, combined with an estimate of its likely
metallicity dependence. This suggests that either star formation at high
redshifts has been significantly underestimated, for example due to a dominant
contribution from faint, undetected galaxies, or that GRB production is
enhanced in the conditions of early star formation, beyond those usually
ascribed to lower metallicity.Comment: 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 34 in eConf
Proceedings C130414
- âŠ