A Borel-Cantelli lemma for intermittent interval maps

We consider intermittent maps T of the interval, with an absolutely continuous invariant probability measure \mu. Kim showed that there exists a sequence of intervals A_n such that \sum \mu(A_n)=\infty, but \{A_n\} does not satisfy the dynamical Borel-Cantelli lemma, i.e., for almost every x, the set \{n : T^n(x)\in A_n\} is finite. If \sum \Leb(A_n)=\infty, we prove that \{A_n\} satisfies the Borel-Cantelli lemma. Our results apply in particular to some maps T whose correlations are not summable.Comment: 7 page

Algebraic entropy for algebraic maps

We propose an extension of the concept of algebraic entropy, as introduced by Bellon and Viallet for rational maps, to algebraic maps (or correspondences) of a certain kind. The corresponding entropy is an index of the complexity of the map. The definition inherits the basic properties from the definition of entropy for rational maps. We give an example with positive entropy, as well as two examples taken from the theory of Backlund transformations

Rare events, escape rates and quasistationarity: some exact formulae

We present a common framework to study decay and exchanges rates in a wide class of dynamical systems. Several applications, ranging form the metric theory of continuons fractions and the Shannon capacity of contrained systems to the decay rate of metastable states, are given

The compound Poisson limit ruling periodic extreme behaviour of non-uniformly hyperbolic dynamics

We prove that the distributional limit of the normalised number of returns to small neighbourhoods of periodic points of non-uniformly hyperbolic dynamical systems is compound Poisson. The returns to small balls around a fixed point in the phase space correspond to the occurrence of rare events, or exceedances of high thresholds, so that there is a connection between the laws of Return Times Statistics and Extreme Value Laws. The fact that the fixed point in the phase space is a repelling periodic point implies that there is a tendency for the exceedances to appear in clusters whose average sizes is given by the Extremal Index, which depends on the expansion of the system at the periodic point. We recall that for generic points, the exceedances, in the limit, are singular and occur at Poisson times. However, around periodic points, the picture is different: the respective point processes of exceedances converge to a compound Poisson process, so instead of single exceedances, we have entire clusters of exceedances occurring at Poisson times with a geometric distribution ruling its multiplicity. The systems to which our results apply include: general piecewise expanding maps of the interval (Rychlik maps), maps with indifferent fixed points (Manneville-Pomeau maps) and Benedicks-Carleson quadratic maps.Comment: To appear in Communications in Mathematical Physic

Intercomparison Exercise for Heavy Metals in PM10

The Joint Research Centre (JRC) has carried out an Intercomparison Exercise (IE) for the determination of heavy metals in particulate matter (PM10). The IE focussed on Lead (Pb), Arsenic (As), Nickel (Ni) and Cadmium (Cd), the heavy metals regulated by the 1st and 4th Daughter Directives for Air Pollution. Copper (Cu), Chromium (Cr) and Zinc (Zn), the elements included in the EMEP programme together with Aluminium (Al), Cobalt (Co), Iron (Fe), Manganese (Mn) and Vanadium (V) were also tested. Fourteen Laboratories, generally members of the Network of Air Quality Reference Laboratories (AQUILA), participated in the IE. The participants mainly used microwave digestion with nitric acid and hydrogen peroxide and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) or Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) for analysis as recommended in the reference method (EN 14902). However, a few participants used other methods: Energy Dispersive X-ray Fluorescence (EDXRF), Atomic Emission Spectrometry (ICP-AES) and Voltammetry for analysis and vaporisation on hot plate before microwave digestion, Soxhlet extraction, high pressure or cold Hydrogen Fluoride methods for digestion. Each participant received 5 samples to be analysed: a liquid sample prepared by dilution of a Certified Reference Material (CRM), a solution of a dust CRM sample digested by the JRC13F, a sub-sample of a dust CRM that each participating laboratory had to digest and analyse, a solution prepared by JRC after digestion of an exposed filter and a pair of filters (one blank filter and one exposed filter) to be digested and analysed by each participant. For 89 % of all types of samples, the DQOs of the 1st and 4th European Directives (uncertainty of 25 % for Pb and 40 % for As, Cd and Ni) were met. All together, this is a very good score. The best results were obtained for the liquid CRM, dust CRM digested by JRC, dust CRM and filter digested by JRC with 92, 90, 96 and 93 % of DQOs being met, respectively. It was found that the DQOs were not met if the difference of acidity between test samples and participant calibration standards was high. Conversely, only 76 % of DQOs were met for the filter to be digested by each participant with (about 85 % for Cd and Ni, 73/64 % for Pb and As, the most difficult element to determine). The worst results were associated with special events: explosion in microwave oven during digestion for two participants, a wrong dilution factor used by one participant and a huge contamination in the blank filter for another participant. Among the two explosions, one of them was probably the effect of a lack of temperature control in the digestion vessel. For the other explosion, the microwave digestion and the digestion program advised by EN 14902 is to be questioned. Moreover, satisfactory results were obtained using Soxhlet extraction, high pressure method and cold Hydrogen Fluoride digestion methods which are not presented in EN 14902. The DQOs of As and Cd could not be met with EDXRF whose limit of detection was too high for these two elements and for Cd using Voltammetry which suffered a strong interference for this element. Regarding the methods of analysis, apart the points mentioned just before about EDXRF and Voltammetry, good results were observed using ICP-OES for Cd, Ni and Pb. A few discrepancies were also registered for GF-AAS and ICP-MS but they were created by the special events or acidity problem mentioned before. This shows that even though GF-AAS and ICP-MS are found suitable, the implementation by each participant may be responsible for important mistakes.JRC.H.4-Transport and air qualit

Mooring line fatigue damage evaluation for floating marine energy converters: Field measurements and prediction

publication-status: Publishedtypes: ArticleThe vision of large-scale commercial arrays of floating marine energy converters (MECs) necessitates the robust, yet cost-effective engineering of devices. Given the continuous environmental loading, fatigue has been iden- tified as one of the key engineering challenges. In particular the mooring sys- tem which warrants the station-keeping of such devices is subject to highly cyclic, non-linear load conditions, mainly induced by the incident waves. To ensure the integrity of the mooring system the lifecycle fatigue spec- trum must be predicted in order to compare the expected fatigue damage against the design limits. The fatigue design of components is commonly as- sessed through numerical modelling of representative load cases. However, for new applications such as floating marine energy converters numerical models are often scantily validated. This paper describes an approach where load measurements from large- scale field trials at the South West Mooring Testing Facility (SWMTF) are used to calculate and predict the fatigue damage. The described procedure employs a Rainflow cycle analysis in conjunction with the Palmgren-Miner rule to estimate the accumulated damage for the deployment periods and individual sea states. This approach allows an accurate fatigue assessment and prediction of mooring lines at a design stage, where field trial load measurements and wave climate information of potential installation sites are available. The mooring design can thus be optimised regarding its fatigue life and costly safety factors can be reduced. The proposed method also assists in monitoring and assessing the fatigue life during deployment periods

Gene Expression Profiles of Chicken Embryo Fibroblasts in Response to Salmonella Enteritidis Infection

The response of chicken to non-typhoidal Salmonella infection is becoming well characterised but the role of particular cell types in this response is still far from being understood. Therefore, in this study we characterised the response of chicken embryo fibroblasts (CEFs) to infection with two different S. Enteritidis strains by microarray analysis. The expression of chicken genes identified as significantly up- or down-regulated (≥3-fold) by microarray analysis was verified by real-time PCR followed by functional classification of the genes and prediction of interactions between the proteins using Gene Ontology and STRING Database. Finally the expression of the newly identified genes was tested in HD11 macrophages and in vivo in chickens. Altogether 19 genes were induced in CEFs after S. Enteritidis infection. Twelve of them were also induced in HD11 macrophages and thirteen in the caecum of orally infected chickens. The majority of these genes were assigned different functions in the immune response, however five of them (LOC101750351, K123, BU460569, MOBKL2C and G0S2) have not been associated with the response of chicken to Salmonella infection so far. K123 and G0S2 were the only 'non-immune' genes inducible by S. Enteritidis in fibroblasts, HD11 macrophages and in the caecum after oral infection. The function of K123 is unknown but G0S2 is involved in lipid metabolism and in β-oxidation of fatty acids in mitochondria

Primary Raynaud's phenomenon in an infant: a case report and review of literature

Raynaud's phenomenon (RP) is an extremely unusual finding in early infancy. In the present report we describe a one-month-old previously healthy male infant who presented with unilateral acrocyanosis. Although infantile acrocyanosis is known to be a benign and self-resolving condition, it is generally bilateral and symmetric. The unilateral nature of the acrocyanosis was an atypical finding in this infant. Consequently, he was closely monitored to evaluate the progression of his acrocyanosis. Based on his benign clinical course and failure to demonstrate other etiologies contributing to his acrocyanosis, he was diagnosed to have primary RP. Due to the rarity of RP in children, we review the progress in understanding the pathophysiology, epidemiology and management of RP and additionally discuss the differential diagnosis of unilateral and bilateral acrocyanosis in infants

Functional Assessment of EnvZ/OmpR Two-Component System in Shewanella oneidensis

EnvZ and OmpR constitute the bacterial two-component signal transduction system known to mediate osmotic stress response in a number of Gram-negative bacteria. In an effort to understand the mechanism through which Shewanella oneidensis senses and responds to environmental osmolarity changes, structure of the ompR-envZ operon was determined with Northern blotting assay and roles of the EnvZ/OmpR two-component system in response to various stresses were investigated with mutational analysis, quantitative reverse transcriptase PCR (qRT-PCR), and phenotype microarrays. Results from the mutational analysis and qRT-PCR suggested that the EnvZ/OmpR system contributed to osmotic stress response of S. oneidensis and very likely engaged a similar strategy employed by E. coli, which involved reciprocal regulation of two major porin coding genes. Additionally, the ompR-envZ system was also found related to cell motility. We further showed that the ompR-envZ dependent regulation of porin genes and motility resided almost completely on ompR and only partially on envZ, indicating additional mechanisms for OmpR phosphorylation. In contrast to E. coli lacking ompR-envZ, however, growth of S. oneidensis did not show a significant dependence on ompR-envZ even under osmotic stress. Further analysis with phenotype microarrays revealed that the S. oneidensis strains lacking a complete ompR-envZ system displayed hypersensitivities to a number of agents, especially in alkaline environment. Taken together, our results suggest that the function of the ompR-envZ system in S. oneidensis, although still connected with osmoregulation, has diverged considerably from that of E. coli. Additional mechanism must exist to support growth of S. oneidensis under osmotic stress