1,250 research outputs found
Ergodipotent maps and commutativity of elements in noncommutative rings and algebras with twisted intertwining
AbstractA property of algebraic dependence between two commuting elements is shown to hold in a more general setting than that in which it has previously been established. Key conditions are identified and some methods for establishing them are given.Moreover the class of algebras with a generalised Weyl structure, generalising the so-called Generalised Weyl Algebras (GWAs) or hyperbolic rings, is introduced and studied. We also present an interesting class of algebras which are not GWAs but share many of their properties by virtue of their generalised Weyl structure. For these classes of algebras, centralisers and algebraic dependence are investigated
URWARE Wastewater Treatment Plant Models
In this document, a large number of mathematical models describing various physical, biological and chemical processes in a wastewater treatment plant are presented. In most cases, the models are fairly simple as they are inteded for steady-state simulations based on yearly averages of the influent wastewater charteristics. The combination of models forms a software tool namned URWARE (URban WAter REsearch model), which is a tool for substance flow analysis and energy calculations in wastewater treatment systems. All models are based on the MATLAB/Simulink platform. The different models can be combined in any fashion thereby creating various system structures that can be analysed and compared. The models keep track of numerous substances related to wastewater, such as organic substances, nutrients and to some extent heavy metals. Within all models the release of environmentally hazardous substances to water, soil and air are calculated. The results can be used as one (of many) information pathways for strategic decision making related to urban water systems. The individual models are described one by one and their behaviours are exemplified by simulation results. In many cases, comparisons with other available software models are given to validate (or at least make plausible) the results produced by the fairly simple URWARE models. Simulation results based on a combination of models into a complete wastewater treatment plant are also presented. However, details about the underlying theory and hypotheses on which the models are based cannot always be sufficiently described due to space limitations. Moreover, users should always be critical to any results predicted by models and not take them for granted simply because they have been calculated by a computer model. Knowledge about the real processes and comparisons with real data are imperative to evaluate whether the predicted results are reasonable or not. For the interested reader the complete source code to all models is included in an extensive appendix. A modelling task of this magnitude is never completed. The proposed models can always be further developed, improved and refined. Consequently, the models described in this document only represent the first version of the URWARE software. Many issues remain to be solved and further improvements to be done. However, it is the hope of the authors that the presented models are mature enough to be used, evaluated, modified and improved by other users outside the URWARE task group
Near Real Time Data Processing In ICOS RI
This paper describes the implementation of (near)
real-time (NRT) data processing in the recently launched
European environmental research infrastructure ICOS. NRT
applications include handling of raw sensor data (including safe
storage and quality control), processing and evaluation of
greenhouse gas mixing ratios and exchange fluxes, and the
provision of data to the RI’s user communities
Evidence-Based Interventions and Strategies for the Grand Challenges Approach: The Need for Judgement
What is the value of evidence-based interventions in addressing “Grand Challenges”?
Building upon the EPOS Grand Challenges work (Sakhrani et al., 2017), this paper explores
whether evidence-based approaches developed for management and policy are relevant to
addressing Grand Challenges. It discusses the criticisms of the Evidence-based Management
approach and argues that evidence is a necessary, but not sufficient input in the decisionmaking process of addressing Grand Challenges
UK Criteria for Uterus Transplantation: A Review
Absolute Uterine Factor Infertility (AUFI) is the final hurdle for assisted reproductive
treatments. Uterus transplant trials are happening worldwide; in order to advance the
debate around uterine transplantation (UTx) this article considers selection criteria for
clinical trials from a UK perspective and makes recommendations for future selection
criteria for UTx treatment. Recommendations advanced include the use of donor eggs,
access for single women and women in same-sex relationships, prohibiting
participation of women who are already mothers, and a preference for deceased
donors and bioengineered uteri. With UTx treatment on the horizon it is important to
proactively consider future selection criteria
Deformations of Lie Algebras using -derivations
In this article we develop an approach to deformations of the Witt and
Virasoro algebras based on -derivations. We show that -twisted
Jacobi type identity holds for generators of such deformations. For the
-twisted generalization of Lie algebras modeled by this construction,
we develop a theory of central extensions. We show that our approach can be
used to construct new deformations of Lie algebras and their central
extensions, which in particular include naturally the -deformations of the
Witt and Virasoro algebras associated to -difference operators, providing
also corresponding q-deformed Jacobi identities.Comment: 52 page
The rp-process and new measurements of beta-delayed proton decay of light Ag and Cd isotopes
Recent network calculations suggest that a high temperature rp-process could
explain the abundances of light Mo and Ru isotopes, which have long challenged
models of p-process nuclide production. Important ingredients to network
calculations involving unstable nuclei near and at the proton drip line are
-halflives and decay modes, i.e., whether or not -delayed proton
decay takes place. Of particular importance to these network calculation are
the proton-rich isotopes Ag, Ag, Cd and Cd. We
report on recent measurements of -delayed proton branching ratios for
Ag, Ag, and Cd at the on-line mass separator at GSI.Comment: 4 pages, uses espcrc1.sty. Proceedings of the 4th International
Symposium Nuclei in the Cosmos, June 1996, Notre Dame/IN, USA, Ed. M.
Wiescher, to be published in Nucl.Phys.A. Also available at
ftp://ftp.physics.ohio-state.edu/pub/nucex/nic96-gs
Fragmentation of exotic oxygen isotopes
Abrasion-ablation models and the empirical EPAX parametrization of projectile fragmentation are described. Their cross section predictions are compared to recent data of the fragmentation of secondary beams of neutron-rich, unstable 19,20,21O isotopes at beam energies near 600 MeV/nucleon as well as data for stable 17,18O beams
Visual onset expands subjective time
We report a distortion of subjective time perception in which the duration of a first interval is perceived to be longer than the succeeding interval of the same duration. The amount of time expansion depends on the onset type defining the first interval. When a stimulus appears abruptly, its duration is perceived to be longer than when it appears following a stationary array. The difference in the processing time for the stimulus onset and motion onset, measured as reaction times, agrees with the difference in time expansion. Our results suggest that initial transient responses for a visual onset serve as a temporal marker for time estimation, and a systematic change in the processing time for onsets affects perceived time
The effects of continued azacitidine treatment cycles on response in higher risk patients with myelodysplastic syndromes: an update
The international, phase III, multi-centre AZA-001 trial demonstrated azacitidine (AZA) is the first treatment to significantly extend overall survival (OS) in higher risk myelodysplastic syndromes (MDS) patients (Fenaux (2007) Blood 110 817). The current treatment paradigm, which is based on a relationship between complete remission (CR) and survival, is increasingly being questioned (Cheson (2006) Blood 108 419). Results of AZA-001 show CR is sufficient but not necessary to prolong OS (List (2008) Clin Oncol 26 7006). Indeed, the AZA CR rate in AZA-001 was modest (17%), while partial remission (PR, 12%) and haematological improvement (HI, 49%) were also predictive of prolonged survival. This analysis was conducted to assess the median number of AZA treatment cycles associated with achievement of first response, as measured by IWG 2000-defined CR, PR or HI (major + minor). The number of treatment cycles from first response to best response was also measured
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