4,592 research outputs found

    Simultaneous Kummer congruences and E\mathbb{E}_\infty-orientations of KO and tmf

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    Building on results of M. Ando, M.J. Hopkins and C. Rezk, we show the existence of uncountably many E\mathbb{E}_\infty-String orientations of real K-theory KO and of topological modular forms tmf, generalizing the A^\hat{A}- (resp. the Witten) genus. Furthermore, the obstruction to lifting an E\mathbb{E}_\infty-String orientations from KO to tmf is identified with a classical Iwasawa-theoretic condition. The common key to all these results is a precise understanding of the classical Kummer congruences, imposed for all primes simultaneously. This result is of independent arithmetic interest.Comment: final versio

    Renewing Criminalized and Hegemonic Cultural Landscapes

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    The Mafia's long historical pedigree in Mezzogiorno, Southern Italy, has empowered the Mafioso as a notorious, uncontested, and hegemonic figure. The counter-cultural resistance against the mafiosi culture began to be institutionalized in the early 1990s. Today, Libera Terra is the largest civil society organization in the country that uses the lands confiscated from the Mafia as a space of cultural repertoire to realize its ideals. Deploying labor force through volunteer participation, producing biological fruits and vegetables, and providing information to the students on the fields are the principal cultural practices of this struggle. The confiscated lands make the Italian experience of anti-Mafia resistance a unique example by connecting the land with the ideals of cultural change. The sociocultural resistance of Libera Terra conveys a political message through these practices and utters that the Mafia is not invincible. This study draws the complex panorama of the Mafia and anti-Mafia movement that uses the ‘confiscated lands’ as cultural and public spaces for resistance and socio-cultural change. In doing so, this article sheds new light on the relationship between rural criminology and crime prevention policies in Southern Italy by demonstrating how community development practice of Libera Terra changes the meaning of landscape through iconographic symbolism and ethnographic performance

    Efectos del desentrenamiento sobre los valores antropométricos en jóvenes futbolistas

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    When executing a race at full speed with change-of-direction force components are highly involved. These components are being specifically trained through plyometric exercises, among others. Few studies evaluate on one side explosive and reactive strength (1,2) and their correlation with short change-of-direction sprints. Once analyzed the evidences showed in some studies reviewed (3,4,5,6,7), our purpose is to determine the relationship between both explosive and reactive strength measures and short change-of-direction sprints in order to find whether the countermovement jump (CMJ) force manifestation helps predicting the performance level during change-of-direction 90º acceleration sprints.El desentrenamiento ha sido definido (Mújika et al., 2001a) como pérdida parcial o completa de las adaptaciones fisiológicas, anatómicas y del rendimiento conseguido con el entrenamiento y como una consecuencia de la reducción o suspensión del proceso de entrenamiento. Con este estudio pretendemos evaluar la influencia del desentrenamiento sobre las variables antropométricas en jóvenes futbolistas (13-15 años). Los resultados nos muestran que las variables antropométricas son una herramienta exacta evaluable en futbolistas en formació

    High prevalence of porcine Hokovirus in German wild boar populations

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    Porcine Hokovirus (PHoV) was recently discovered in Hong Kong. This new Parvovirus of pigs is closely related to the human Parvoviruses 4 and 5 (PARV4/5) and bovine Hokovirus (BHoV). So far, nothing is known about the presence and prevalence of PHoV in regions of the world other than Hong Kong. A study was initiated to investigate PHoV in German wild boars from five different geographical regions, using a newly established quantitative real-time PCR assay. Analysis of collected liver and serum samples revealed high overall prevalence (32.7%; 51/156) of PHoV in wild boars. The prevalence differed between the regions and increased with age. Two near full-length genomes and a large fragment for three additional isolates from different regions were sequenced and used for phylogenetic analysis. The German PHoV sequences from wild boars showed a close relationship with sequences of isolates from Hong Kong

    Ablation lesions in Koch's triangle assessed by three-dimensional myocardial contrast echocardiography

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    BACKGROUND: Myocardial contrast echocardiography (MCE) allows visualization of radiofrequency (RF) ablation lesions in the left ventricle in an animal model. Aim: To test whether MCE allows visualization of RF and cryo ablation lesions in the human right atrium using three-dimensional echocardiography. METHODS: 18 patients underwent catheter ablation of a supraventricular tachycardia and were included in this prospective single-blind study. Twelve patients were ablated inside Koch's triangle and 6, who served as controls, outside this area. Three-dimensional echocardiography of Koch's triangle was performed before and after the ablation procedure in all patients, using respiration and ECG gated pullback of a 9 MHz ICE transducer, with and without continuous intravenous echocontrast infusion (SonoVue, Bracco). Two independent observers analyzed the data off-line. RESULTS: MCE identified ablation lesions as a low contrast area within the normal atrial myocardial tissue. Craters on the endocardial surface were seen in 10 (83%) patients after ablation. Lesions were identified in 11 out of 12 patients (92%). None of the control patients were recognized as having been ablated. The confidence score of the independent echo reviewer tended to be higher when the number of applications increased. CONCLUSIONS: 1. MCE allows direct visualization of ablation lesions in the human atrial myocardium. 2. Both RF and cryo energy lesions can be identified using MCE

    Charge 4e4e superconductivity from pair density wave order in certain high temperature superconductors

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    A number of spectacular experimental anomalies\cite{li-2007,fujita-2005} have recently been discovered in certain cuprates, notably {\LBCO} and {\LNSCO}, which exhibit unidirectional spin and charge order (known as ``stripe order''). We have recently proposed to interpret these observations as evidence for a novel ``striped superconducting'' state, in which the superconducting order parameter is modulated in space, such that its average is precisely zero. Here, we show that thermal melting of the striped superconducting state can lead to a number of unusual phases, of which the most novel is a charge 4e4e superconducting state, with a corresponding fractional flux quantum hc/4ehc/4e. These are never-before observed states of matter, and ones, moreover, that cannot arise from the conventional Bardeen-Cooper-Schrieffer (BCS) mechanism. Thus, direct confirmation of their existence, even in a small subset of the cuprates, could have much broader implications for our understanding of high temperature superconductivity. We propose experiments to observe fractional flux quantization, which thereby could confirm the existence of these states.Comment: 5 pages, 2 figures; new version in Nature Physics format with a discussion of the effective Josephson coupling J2 and minor changes. Mildly edited abstract. v3: corrected versio

    Climate Dynamics: A Network-Based Approach for the Analysis of Global Precipitation

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    Precipitation is one of the most important meteorological variables for defining the climate dynamics, but the spatial patterns of precipitation have not been fully investigated yet. The complex network theory, which provides a robust tool to investigate the statistical interdependence of many interacting elements, is used here to analyze the spatial dynamics of annual precipitation over seventy years (1941-2010). The precipitation network is built associating a node to a geographical region, which has a temporal distribution of precipitation, and identifying possible links among nodes through the correlation function. The precipitation network reveals significant spatial variability with barely connected regions, as Eastern China and Japan, and highly connected regions, such as the African Sahel, Eastern Australia and, to a lesser extent, Northern Europe. Sahel and Eastern Australia are remarkably dry regions, where low amounts of rainfall are uniformly distributed on continental scales and small-scale extreme events are rare. As a consequence, the precipitation gradient is low, making these regions well connected on a large spatial scale. On the contrary, the Asiatic South-East is often reached by extreme events such as monsoons, tropical cyclones and heat waves, which can all contribute to reduce the correlation to the short-range scale only. Some patterns emerging between mid-latitude and tropical regions suggest a possible impact of the propagation of planetary waves on precipitation at a global scale. Other links can be qualitatively associated to the atmospheric and oceanic circulation. To analyze the sensitivity of the network to the physical closeness of the nodes, short-term connections are broken. The African Sahel, Eastern Australia and Northern Europe regions again appear as the supernodes of the network, confirming furthermore their long-range connection structure. Almost all North-American and Asian nodes vanish, revealing that extreme events can enhance high precipitation gradients, leading to a systematic absence of long-range patterns

    Paralytic shellfish poisoning (PSP) toxin binders for optical biosensor technology: problems and possibilities for the future: a review

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    This review examines the developments in optical biosensor technology, which uses the phenomenon of surface plasmon resonance, for the detection of paralytic shellfish poisoning (PSP) toxins. Optical biosensor technology measures the competitive biomolecular interaction of a specific biological recognition element or binder with a target toxin immobilised onto a sensor chip surface against toxin in a sample. Different binders such as receptors and antibodies previously employed in functional and immunological assays have been assessed. Highlighted are the difficulties in detecting this range of low molecular weight toxins, with analogues differing at four chemical substitution sites, using a single binder. The complications that arise with the toxicity factors of each toxin relative to the parent compound, saxitoxin, for the measurement of total toxicity relative to the mouse bioassay are also considered. For antibodies, the cross-reactivity profile does not always correlate to toxic potency, but rather to the toxin structure to which it was produced. Restrictions and availability of the toxins makes alternative chemical strategies for the synthesis of protein conjugate derivatives for antibody production a difficult task. However, when two antibodies with different cross-reactivity profiles are employed, with a toxin chip surface generic to both antibodies, it was demonstrated that the cross-reactivity profile of each could be combined into a single-assay format. Difficulties with receptors for optical biosensor analysis of low molecular weight compounds are discussed, as are the potential of alternative non-antibody-based binders for future assay development in this area

    Order-of-magnitude speedup for steady states and traveling waves via Stokes preconditioning in Channelflow and Openpipeflow

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    Steady states and traveling waves play a fundamental role in understanding hydrodynamic problems. Even when unstable, these states provide the bifurcation-theoretic explanation for the origin of the observed states. In turbulent wall-bounded shear flows, these states have been hypothesized to be saddle points organizing the trajectories within a chaotic attractor. These states must be computed with Newton's method or one of its generalizations, since time-integration cannot converge to unstable equilibria. The bottleneck is the solution of linear systems involving the Jacobian of the Navier-Stokes or Boussinesq equations. Originally such computations were carried out by constructing and directly inverting the Jacobian, but this is unfeasible for the matrices arising from three-dimensional hydrodynamic configurations in large domains. A popular method is to seek states that are invariant under numerical time integration. Surprisingly, equilibria may also be found by seeking flows that are invariant under a single very large Backwards-Euler Forwards-Euler timestep. We show that this method, called Stokes preconditioning, is 10 to 50 times faster at computing steady states in plane Couette flow and traveling waves in pipe flow. Moreover, it can be carried out using Channelflow (by Gibson) and Openpipeflow (by Willis) without any changes to these popular spectral codes. We explain the convergence rate as a function of the integration period and Reynolds number by computing the full spectra of the operators corresponding to the Jacobians of both methods.Comment: in Computational Modelling of Bifurcations and Instabilities in Fluid Dynamics, ed. Alexander Gelfgat (Springer, 2018
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