Declarative Modeling–An Academic Dream or the Future for BPM?

Declarative modeling has attracted much attention over the last years, resulting in the development of several academic declarative modeling techniques and tools. The absence of empirical evaluations on their use and usefulness, however, raises the question whether practitioners are attracted to using those techniques. In this paper, we present a study on what practitioners think of declarative modeling. We show that the practitioners we involved in this study are receptive to the idea of a hybrid approach combining imperative and declarative techniques, rather than making a full shift from the imperative to the declarative paradigm. Moreover, we report on requirements, use cases, limitations, and tool support of such a hybrid approach. Based on the gained insight, we propose a research agenda for the development of this novel modeling approach

Refactoring Process Models in Large Process Repositories.

With the increasing adoption of process-aware information systems (PAIS), large process model repositories have emerged. Over time respective models have to be re-aligned to the real-world business processes through customization or adaptation. This bears the risk that model redundancies are introduced and complexity is increased. If no continuous investment is made in keeping models simple, changes are becoming increasingly costly and error-prone. Though refactoring techniques are widely used in software engineering to address related problems, this does not yet constitute state-of-the art in business process management. Process designers either have to refactor process models by hand or cannot apply respective techniques at all. This paper proposes a set of behaviour-preserving techniques for refactoring large process repositories. This enables process designers to eectively deal with model complexity by making process models better understandable and easier to maintain

The failure of microglia to digest developmental apoptotic cells contributes to the pathology of RNASET2-deficient leukoencephalopathy

The contribution of microglia in neurological disorders is emerging as a leading disease driver rather than a consequence of pathology. RNAseT2‐deficient leukoencephalopathy is a severe childhood white matter disorder affecting patients in their first year of life and mimicking a cytomegalovirus brain infection. The early onset and resemblance of the symptoms to a viral infection suggest an inflammatory and embryonic origin of the pathology. There are no treatments available for this disease as our understanding of the cellular drivers of the pathology are still unknown. In this study, using a zebrafish mutant for the orthologous rnaset2 gene, we have identified an inflammatory signature in early development and an antiviral immune response in mature adult brains. Using the optical transparency and the ex utero development of the zebrafish larvae we studied immune cell behavior during brain development and identified abnormal microglia as an early marker of pathology. Live imaging and electron microscopy identified that mutant microglia displayed an engorged morphology and were filled with undigested apoptotic cells and undigested substrate. Using microglia‐specific depletion and rescue experiments, we identified microglia as drivers of this embryonic phenotype and potential key cellular player in the pathology of RNAseT2‐deficient leukoencephalopathy. Our zebrafish model also presented with reduced survival and locomotor defects, therefore recapitulating many aspects of the human disease. Our study therefore placed our rnaset2 mutant at the forefront of leukodystrophy preclinical models and highlighted tissue‐specific approaches as future therapeutic avenues

Failure to clear developmental apoptosis contributes to the pathology of RNASET2-deficient leukoencephalopathy

The contribution of microglia in neurological disorders is emerging as a leading driver rather than a consequence of pathology. RNAseT2-deficient leukoencephalopathy is a severe childhood white matter disorder affecting patients in their first year of life and mimics a cytomegalovirus brain infection. The early onset and resemblance of the symptoms to an immune response suggest an inflammatory and embryonic origin of the pathology. In this study, we identify deficient microglia as an early marker of pathology. Using the ex utero development and the optical transparency of an rnaset2-deficient zebrafish model, we found that dysfunctional microglia fail to clear apoptotic neurons during brain development. This was associated with increased number of apoptotic cells and behavioural defects lasting into adulthood. This zebrafish model recapitulates all aspect of the human disease to be used as a robust preclinical model. Using microglia-specific depletion and rescue experiments, we identified microglia as potential drivers of the pathology and highlight tissue-specific approaches as future therapeutic avenues

Strange stars in Krori-Barua space-time

The singularity space-time metric obtained by Krori and Barua\cite{Krori1975} satisfies the physical requirements of a realistic star. Consequently, we explore the possibility of applying the Krori and Barua model to describe ultra-compact objects like strange stars. For it to become a viable model for strange stars, bounds on the model parameters have been obtained. Consequences of a mathematical description to model strange stars have been analyzed.Comment: 9 pages (two column), 12 figures. Some changes have been made. " To appear in European Physical Journal C

Current-induced highly dissipative domains in high Tc thin films

We have investigated the resistive response of high Tc thin films submitted to a high density of current. For this purpose, current pulses were applied into bridges made of Nd(1.15)Ba(1.85)Cu3O7 and Bi2Sr2CaCu2O8. By recording the time dependent voltage, we observe that at a certain critical current j*, a highly dissipative domain develops somewhere along the bridge. The successive formation of these domains produces stepped I-V characteristics. We present evidences that these domains are not regions with a temperature above Tc, as for hot spots. In fact this phenomenon appears to be analog to the nucleation of phase-slip centers observed in conventional superconductors near Tc, but here in contrast they appear in a wide temperature range. Under some conditions, these domains will propagate and destroy the superconductivity within the whole sample. We have measured the temperature dependence of j* and found a similar behavior in the two investigated compounds. This temperature dependence is just the one expected for the depairing current, but the amplitude is about 100 times smaller.Comment: 9 pages, 9 figures, Revtex, to appear in Phys. Rev.

Gutzwiller-Correlated Wave Functions: Application to Ferromagnetic Nickel

Ferromagnetic Nickel is the most celebrated iron group metal with pronounced discrepancies between the experimental electronic properties and predictions of density functional theories. In this work, we show in detail that the recently developed multi-band Gutzwiller theory provides a very good description of the quasi-particle band structure of nickel. We obtain the correct exchange splittings and we reproduce the experimental Fermi-surface topology. The correct (111)-direction of the magnetic easy axis and the right order of magnitude of the magnetic anisotropy are found. Our theory also reproduces the experimentally observed change of the Fermi-surface topology when the magnetic moment is oriented along the (001)-axis. In addition to the numerical study, we give an analytical derivation for a much larger class of variational wave-functions than in previous investigations. In particular, we cover cases of superconductivity in multi-band lattice systems.Comment: 35 pages, 3 figure

Process and Data: Two Sides of the Same Coin

Companies increasingly adopt process management technology which offers promising perspectives for realizing flexible information systems. However, there still exist numerous process scenarios not adequately covered by contemporary information systems. One major reason for this deficiency is the insufficient understanding of the inherent relationships existing between business processes on one side and business data on the other. Consequently, these two perspectives are not well integrated in many existing process management systems. This paper emphasizes the need for both object- and process-awareness in future information systems, and illustrates it along several examples. Especially, the relation between these two fundamental perspectives will be discussed, and the role of business objects and data as drivers for both process modeling and process enactment be emphasized. In general, any business process support should consider object behavior as well as object interactions, and therefore be based on two levels of granularity. In addition, data-driven process execution and integrated user access to processes and data are needed. Besides giving insights into these fundamental characteristics, an advanced framework supporting them in an integrated manner will be presented and its application to real-world process scenarios be shown. Overall, a holistic and generic framework integrating processes, data, and users will contribute to overcome many of the limitations of existing process management technology

Flux Phase as a Dynamic Jahn-Teller Phase: Berryonic Matter in the Cuprates?

There is considerable evidence for some form of charge ordering on the hole-doped stripes in the cuprates, mainly associated with the low-temperature tetragonal phase, but with some evidence for either charge density waves or a flux phase, which is a form of dynamic charge-density wave. These three states form a pseudospin triplet, demonstrating a close connection with the E X e dynamic Jahn-Teller effect, suggesting that the cuprates constitute a form of Berryonic matter. This in turn suggests a new model for the dynamic Jahn-Teller effect as a form of flux phase. A simple model of the Cu-O bond stretching phonons allows an estimate of electron-phonon coupling for these modes, explaining why the half breathing mode softens so much more than the full oxygen breathing mode. The anomalous properties of $O^{2-}$ provide a coupling (correlated hopping) which acts to stabilize density wave phases.Comment: Major Revisions: includes comparisons with specific cuprate phonon modes, 16 eps figures, revte