Checking bounded reachability in asynchronous systems by symbolic event tracing

This report presents a new symbolic technique for checking reachability properties of asynchronous systems by reducing the problem to satisfiability in restrained difference logic. The analysis is bounded by fixing a finite set of potential events, each of which may occur at most once in any order. The events are specified using high-level Petri nets. The logic encoding describes the space of possible causal links between events rather than possible sequences of states as in Bounded Model Checking. Independence between events is exploited intrinsically without partial order reductions, and the handling of data is symbolic. On a family of benchmarks, the proposed approach is consistently faster than Bounded Model Checking. In addition, this report presents a compact encoding of the restrained subset of difference logic in propositional logic

Detection methods for non-Gaussian gravitational wave stochastic backgrounds

We address the issue of finding an optimal detection method for a discontinuous or intermittent gravitational wave stochastic background. Such a signal might sound something like popcorn popping. We derive an appropriate version of the maximum likelihood detection statistic, and compare its performance to that of the standard cross-correlation statistic both analytically and with Monte Carlo simulations. The maximum likelihood statistic performs better than the cross-correlation statistic when the background is sufficiently non-Gaussian. For both ground and space based detectors, this results in a gain factor, ranging roughly from 1 to 3, in the minimum gravitational-wave energy density necessary for detection, depending on the duty cycle of the background. Our analysis is exploratory, as we assume that the time structure of the events cannot be resolved, and we assume white, Gaussian noise in two collocated, aligned detectors. Before this detection method can be used in practice with real detector data, further work is required to generalize our analysis to accommodate separated, misaligned detectors with realistic, colored, non-Gaussian noise.Comment: 25 pages, 12 figures, submitted to physical review D, added revisions in response to reviewers comment

Efficacy of a preparation of algae interspaced bentonite as a feed additive for all animal species

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) was asked to deliver a scientific opinion on the efficacy of a preparation of algae interspaced bentonite when used as aflatoxin B1 (AfB1) binder for all animal species; the additive is composed of bentonite feed grade and algae belonging to Ulva spp. The European Commission request follows an opinion of the FEEDAP Panel published in 2016; in that opinion, the FEEDAP Panel could not conclude on the efficacy of the additive. The applicant has submitted additional information to allow the FEEDAP Panel to complete its assessment; these additional data, related to the efficacy of the additive, are the subject of this opinion. In the efficacy study provided, the use of the additive reduced the AfM1 in milk, although this effect seemed to be not consistent over time; this study presented some weaknesses and limitations (incomplete data analysis, reporting and lack of determination of the active substance of the additive in feed) which do not allow the FEEDAP Panel to draw any conclusion on the efficacy of the additive. Due to insufficient evidence, the FEEDAP Panel cannot conclude on the efficacy of the algae interspaced bentonite as a technological feed additive for all animal species

Safety and efficacy of aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs. The additive, that contains at least 66% of aluminosilicate of sodium, potassium, calcium and magnesium as main component, is intended for use as a technological additive (functional groups: (i) anticaking agents) in premixtures and feedingstuffs for pigs at a maximum inclusion level of 30,000 mg/kg. In the absence of data, the FEEDAP Panel could not conclude on the safety of the additive for the target species and the users. The additive is considered safe for the consumer and the environment at the proposed conditions of use. The additive has the potential to act as an anticaking agent in complete feed of pigs at a concentration of 30,000 mg/kg feed

Safety and efficacy of TYFER\u2122 (Ferric tyrosine chelate) as a zootechnical feed additive for chickens, turkeys and minor poultry species for fattening or reared for laying/breeding

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the product TYFERTM (ferric tyrosine chelate) as zootechnical feed additive for chickens, turkeys and minor poultry species for fattening or reared for laying/breeding. The additive is safe for chickens for fattening at the maximum expected level of 200 mg TYFERTM/kg complete feed; this conclusion can be extended to chickens reared for laying/breeding and extrapolated to turkeys and all minor poultry species for fattening or reared for laying/breeding. No concerns for consumer safety are expected from the use of the additive in poultry nutrition. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers that the additive poses a risk to users by inhalation, and should also be considered as an irritant to skin, eyes and mucous membranes. Due to the presence of nickel, ferric tyrosine chelate should also be considered as a dermal and respiratory sensitiser. The supplementation of feed with the additive is not expected to pose an environmental risk. TYFERTM used at the minimum recommended level (20 mg/kg feed) in chickens diets has the potential to improve zootechnical parameters of birds. The additive at 20 mg/kg feed has the potential to reduce the caecal load Campylobacter spp. by at least 1 log10-units in chickens for fattening, thus with a potential impact to reduce the risk of human campylobacteriosis; however, the Panel notes that the load of Campylobacter in the chickens caecum is one of the multiple factors that contribute to Campylobacter load in carcases-meat. The conclusions on the efficacy of the additive can be extended to chickens reared for laying/breeding and extrapolated to turkeys and all minor poultry species for fattening or reared for laying/breeding. The Panel recommends including a specification for maximum lithium content in a potential authorisation of the additive

Nustar and Chandra Insight into the Nature of the 3-40 Kev Nuclear Emission in Ngc 253

We present results from three nearly simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR) and Chandra monitoring observations between 2012 September 2 and 2012 November 16 of the local star-forming galaxy NGC 253. The 3-40 kiloelectron volt intensity of the inner approximately 20 arcsec (approximately 400 parsec) nuclear region, as measured by NuSTAR, varied by a factor of approximately 2 across the three monitoring observations. The Chandra data reveal that the nuclear region contains three bright X-ray sources, including a luminous (L (sub 2-10 kiloelectron volt) approximately few 10 (exp 39) erg per s) point source located approximately 1 arcsec from the dynamical center of the galaxy (within the sigma 3 positional uncertainty of the dynamical center); this source drives the overall variability of the nuclear region at energies greater than or approximately equal to 3 kiloelectron volts. We make use of the variability to measure the spectra of this single hard X-ray source when it was in bright states. The spectra are well described by an absorbed (power-law model spectral fit value, N(sub H), approximately equal to 1.6 x 10 (exp 23) per square centimeter) broken power-law model with spectral slopes and break energies that are typical of ultraluminous X-ray sources (ULXs), but not active galactic nuclei (AGNs). A previous Chandra observation in 2003 showed a hard X-ray point source of similar luminosity to the 2012 source that was also near the dynamical center (Phi is approximately equal to 0.4 arcsec); however, this source was offset from the 2012 source position by approximately 1 arcsec. We show that the probability of the 2003 and 2012 hard X-ray sources being unrelated is much greater than 99.99% based on the Chandra spatial localizations. Interestingly, the Chandra spectrum of the 2003 source (3-8 kiloelectron volts) is shallower in slope than that of the 2012 hard X-ray source. Its proximity to the dynamical center and harder Chandra spectrum indicate that the 2003 source is a better AGN candidate than any of the sources detected in our 2012 campaign; however, we were unable to rule out a ULX nature for this source. Future NuSTAR and Chandra monitoring would be well equipped to break the degeneracy between the AGN and ULX nature of the 2003 source, if again caught in a high state

Anomaly analysis of Hawking radiation from Kaluza-Klein black hole with squashed horizon

Considering gravitational and gauge anomalies at the horizon, a new method that to derive Hawking radiations from black holes has been developed by Wilczek et al. In this paper, we apply this method to non-rotating and rotating Kaluza-Klein black holes with squashed horizon, respectively. For the rotating case, we found that, after the dimensional reduction, an effective U(1) gauge field is generated by an angular isometry. The results show that the gauge current and energy-momentum tensor fluxes are exactly equivalent to Hawking radiation from the event horizon.Comment: 15 pages, no figures, the improved version, accepted by Eur. Phys. J.

Nurture, nature and some very dubious social skills: An interpretative phenomenological analysis of talent identification practices in elite English youth soccer

This paper reports qualitative findings regarding the concepts and practices utilised in talent identification (TI) among professional coaches working in English youth soccer. Using interpretative phenomenological analysis, detailed interviews with seven such coaches are explored, with a view to elucidating the links between understanding, practice, experience and professional context. Findings reveal three superordinate themes, relating to (1) a primarily ‘nurtured’ and trainable understanding of the broad concept of talent itself, (2) an ostensibly contradictory model of semi-static player psychology, and (3) a highly selective mechanism for separating evidence for ‘mental strength’ and ‘social skills’. It is contended that these findings underscore a case for more thorough interrogation of the real worlds inhabited by coaches, such that ideas about ‘good practice’ in TI might be more effectively reconciled with grounded knowledge of the practical everyday necessities of being a coach