1,682 research outputs found
Gas of wormholes: a possible ground state of Quantum Gravity
In order to gain insight into the possible Ground State of Quantized
Einstein's Gravity, we have derived a variational calculation of the energy of
the quantum gravitational field in an open space, as measured by an asymptotic
observer living in an asymptotically flat space-time. We find that for Quantum
Gravity (QG) it is energetically favourable to perform its quantum fluctuations
not upon flat space-time but around a ``gas'' of wormholes of mass m_p, the
Planck mass (m_p ~= 10^{19}GeV) and average distance l_p, the Planck length
a_p(a_p ~= 10^{-33}cm). As a result, assuming such configuration to be a good
approximation to the true Ground State of Quantum Gravity, space-time, the
arena of physical reality, turns out to be well described by Wheeler's quantum
foam and adequately modeled by a space-time lattice with lattice constant l_p,
the Planck lattice.Comment: 56 pages, revised version to appear in General Relativity and
Gravitation (2000
Some unique group-measure space decomposition results
Using an approach emerging from the theory of closable derivations on von
Neumann algebras, we exhibit a class of groups CR satisfying the following
property: given any groups G_1, G_2 in CR, then any free, ergodic, measure
preserving action on a probability space G_1 x G_2 on X gives rise to a von
Neumann algebra with unique group measure space Cartan subalgebra. Pairing this
result with Popa's Orbit Equivalence Superrigidity Theorem we obtain new
examples of W*-superrigid actions.Comment: Revised proofs in Section
Uniqueness in chess studies
Van der Heijden’s ENDGAME STUDY DATABASE IV, HhdbIV, is the definitive collection of 76,132 chess studies. In each one, White is to achieve the stipulated goal, win or draw: study solutions should be essentially unique with minor alternatives at most. In this second note on the mining of the database, we use the definitive Nalimov endgame tables to benchmark White’s moves in sub-7-man chess against this standard of uniqueness. Amongst goal-compatible mainline positions and goal-achieving moves, we identify the occurrence of absolutely unique moves and analyse the frequency and lengths of absolutely-unique-move sequences, AUMSs. We identify the occurrence of equi-optimal moves and suboptimal moves and refer to a defined method for classifying their significance
The signalling channel of Central Bank interventions:modelling the Yen/US dollar exchange rate
This paper presents a theoretical framework analysing the signalling channel of exchange rate interventions as an informational trigger. We develop an implicit target zone framework with learning in order to model the signalling channel. The theoretical premise of the model is that interventions convey signals that communicate information about the exchange rate objectives of the central bank. The model is used to analyse the impact of Japanese FX interventions during the period 1999--2011 on the yen/US dollar dynamics
Development and Optimisation of the GM Oilseed Rape Event-Specific Pre-Spotted Plate (OSR-PSP) EURL-SP-07/16
This report describes the development of the "GM oilseed rape event-specific pre-spotted plates (OSR-PSP)" as a ready-to-use tool for GMO detection and identification.
The OSR-PSP allows the detection of all GM oilseed rape events listed in the EU register of authorised GM events as of February 2017 and one not authorised event. The plate includes a total of 12 assays, consisting of 11 event-specific assays and one taxon-specific assay selected from those validated and approved by the EU Reference Laboratory for GM Food and Feed (EURL GMFF).
The reaction conditions were standardised and the performance of the assays, in terms of specificity and sensitivity, were re-assessed in a single-laboratory study.
The results confirm that the assays, under the new reaction conditions, fulfil the EU requirements for GMO testing and can be used for the detection of single and stacked oilseed rape GM events in food and feed samples.JRC.F.5-Food and Feed Complianc
Bits from Biology for Computational Intelligence
Computational intelligence is broadly defined as biologically-inspired
computing. Usually, inspiration is drawn from neural systems. This article
shows how to analyze neural systems using information theory to obtain
constraints that help identify the algorithms run by such systems and the
information they represent. Algorithms and representations identified
information-theoretically may then guide the design of biologically inspired
computing systems (BICS). The material covered includes the necessary
introduction to information theory and the estimation of information theoretic
quantities from neural data. We then show how to analyze the information
encoded in a system about its environment, and also discuss recent
methodological developments on the question of how much information each agent
carries about the environment either uniquely, or redundantly or
synergistically together with others. Last, we introduce the framework of local
information dynamics, where information processing is decomposed into component
processes of information storage, transfer, and modification -- locally in
space and time. We close by discussing example applications of these measures
to neural data and other complex systems
Development and Validation of Markers for the Fertility Restorer Gene Rf1 in Sunflower
Hybrid breeding in sunflowers based on CMS PET1 requires development of restorer lines carrying, in most cases, the restorer gene Rf1. Markers for marker-assisted selection have been developed, but there is still need for closer, more versatile, and co-dominant markers linked to Rf1. Homology searches against the reference sunflower genome using sequences of cloned markers, as well as Bacterial Artificial Chromosome (BAC)-end sequences of clones hybridizing to them, allowed the identification of two genomic regions of 30 and 3.9 Mb, respectively, as possible physical locations of the restorer gene Rf1 on linkage group 13. Nine potential candidate genes, encoding six pentatricopeptide repeat proteins, one tetratricopeptide-like helical domain, a probable aldehyde dehydrogenase 22A1, and a probable poly(A) polymerase 3 (PAPS3), were identified in these two genomic regions. Amplicon targeted next generation sequencing of these nine candidate genes for Rf1 was performed in an association panel consisting of 27 maintainer and 32 restorer lines and revealed the presence of 210 Single Nucleotide Polymorphisms (SNPs) and 67 Insertions/Deletions (INDELs). Association studies showed significant associations of 10 SNPs with fertility restoration (p-value lt 10(-4)), narrowing Rf1 down to three candidate genes. Three new markers, one co-dominant marker 67N04_P and two dominant markers, PPR621.5R for restorer, and PPR621.5M for maintainer lines were developed and verified in the association panel of 59 sunflower lines. The versatility of the three newly developed markers, as well as of three existing markers for the restorer gene Rf1 (HRG01 and HRG02, Cleaved Amplified Polymorphic Sequence (CAPS)-marker H13), was analyzed in a large association panel consisting of 557 accessions
Data generator for evaluating ETL process quality
Obtaining the right set of data for evaluating the fulfillment of different quality factors in the extract-transform-load (ETL) process design is rather challenging. First, the real data might be out of reach due to different privacy constraints, while manually providing a synthetic set of data is known as a labor-intensive task that needs to take various combinations of process parameters into account. More importantly, having a single dataset usually does not represent the evolution of data throughout the complete process lifespan, hence missing the plethora of possible test cases. To facilitate such demanding task, in this paper we propose an automatic data generator (i.e., Bijoux). Starting from a given ETL process model, Bijoux extracts the semantics of data transformations, analyzes the constraints they imply over input data, and automatically generates testing datasets. Bijoux is highly modular and configurable to enable end-users to generate datasets for a variety of interesting test scenarios (e.g., evaluating specific parts of an input ETL process design, with different input dataset sizes, different distributions of data, and different operation selectivities). We have developed a running prototype that implements the functionality of our data generation framework and here we report our experimental findings showing the effectiveness and scalability of our approach.Peer ReviewedPostprint (author's final draft
- …