365 research outputs found

    Gauge Theories in AdS5AdS_5 and Fine-Lattice Deconstruction

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    The logarithmic energy dependence of gauge couplings in AdS_5 emerges almost automatically when the theory is deconstructed on a coarse lattice. Here we study the theory away from the coarse-lattice limit. While we cannot analytically calculate individual KK masses for a fine lattice, we can calculate the product of all non-zero masses. This allows us to write down the gauge coupling at low energies for any lattice-spacing and curvature. As expected, the leading log behaviour is corrected by power-law contributions, suppressed by the curvature. We then turn to intermediate energies, and discuss the gauge coupling and the gauge boson profile in perturbation theory around the coarse-lattice limit.Comment: 17 pages, 1 figure, typos in listing version of abstract correcte

    Massive Supergravity and Deconstruction

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    We present a simple superfield Lagrangian for massive supergravity. It comprises the minimal supergravity Lagrangian with interactions as well as mass terms for the metric superfield and the chiral compensator. This is the natural generalization of the Fierz-Pauli Lagrangian for massive gravity which comprises mass terms for the metric and its trace. We show that the on-shell bosonic and fermionic fields are degenerate and have the appropriate spins: 2, 3/2, 3/2 and 1. We then study this interacting Lagrangian using goldstone superfields. We find that a chiral multiplet of goldstones gets a kinetic term through mixing, just as the scalar goldstone does in the non-supersymmetric case. This produces Planck scale (Mpl) interactions with matter and all the discontinuities and unitarity bounds associated with massive gravity. In particular, the scale of strong coupling is (Mpl m^4)^1/5, where m is the multiplet's mass. Next, we consider applications of massive supergravity to deconstruction. We estimate various quantum effects which generate non-local operators in theory space. As an example, we show that the single massive supergravity multiplet in a 2-site model can serve the function of an extra dimension in anomaly mediation.Comment: 24 pages, 2 figures, some color. Typos fixed and refs added in v

    The influence of local meteorological conditions on the circadian rhythm of corn (Zea mays L.) pollen emission

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    Field experiments were performed to study the diurnal cycle of corn pollen emission and its relation to local meteorological conditions, including temperature, relative humidity, solar radiation, mean wind speed, and turbulence quantities. Pollen concentrations were measured from canopy height to twice this level using four Rotorod samplers located on a pole in the middle of the corn field. The measured pollen concentration at canopy height was used as a surrogate for the pollen source strength while the concentrations above canopy represented the pollen transported upwards from canopy height. At twice the canopy height, the pollen concentration decreased considerably to about 30% of the canopy height values. During the mornings, pollen was emitted in large quantities while during the afternoons, airborne pollen concentrations decreased and no significant atmospheric pollen was measured from about 2 h prior to sunset until sunrise the next morning. The actual time that airborne pollen was first recorded differed from day-to-day and depended on the time required for the anthers to dry and open, as well as there being sufficiently strong winds to entrain the pollen away from the plants. On four consecutive mornings diurnal atmospheric pollen concentration distributions were bi-modal in time. The first pollen concentration peak happened shortly before the direct irradiance peak on the anthers suggesting that direct solar irradiation might be important for drying the anthers. The subsequent dip in pollen concentration seemed to be linked to a lull in mean and turbulent wind conditions. Analysis of the vertical velocity fluctuations, sw, showed that the fraction of pollen transported upwards from canopy height increased with increasing sw. In addition, Quadrant– Hole analysis applied to the turbulence data sets of 2 days suggested that low values of ejection duration fractions were associated with low values of pollen concentration, while high values were associated with high concentration values. The diurnal pattern of ejection duration fractions was similar to the pattern of the fraction of pollen that reached twice the canopy height, indicatin

    Early adoption of the human papillomavirus vaccine among hispanic adolescent males in the united states

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    BACKGROUND: Human papillomavirus (HPV) infection is common among Hispanic males, but to the authors' knowledge little is known regarding HPV vaccination in this population. The authors examined the early adoption of the HPV vaccine among a national sample of Hispanic adolescent males.METHODS: The authors analyzed provider-verified HPV vaccination data from the 2010 through 2012 National Immunization Survey-Teen (NIS-Teen) for Hispanic males aged 13 years to 17 years (n=4238).Weighted logistic regression identified correlates of HPV vaccine initiation (receipt of ≥1 doses).RESULTS: HPV vaccine initiation was 17.1% overall, increasing from 2.8% in 2010 to 31.7% in 2012 (P<.0001). Initiation was higher among sons whose parents had received a provider recommendation to vaccinate compared with those whose parents had not (53.3% vs 9.0%; odds ratio, 8.77 [95% confidence interval, 6.05-12.70]). Initiation was also higher among sons who had visited a health care provider within the previous year (odds ratio, 2.42; 95% confidence interval, 1.39-4.23). Among parents with unvaccinated sons, Spanish-speaking parents reported much higher intent to vaccinate compared with English-speaking parents (means: 3.52 vs 2.54; P<.0001). Spanish-speaking parents were more likely to indicate lack of knowledge (32.9% vs 19.9%) and not having received a provider recommendation (32.2% vs 17.7%) as the main reasons for not intending to vaccinate (both P<.05).CONCLUSIONS: HPV vaccination among Hispanic adolescent males has increased substantially in recent years. Ensuring health care visits and provider recommendation will be key for continuing this trend. Preferred language may also be important for increasing HPV vaccination and addressing potential barriers to vaccination

    PIV Measurements in the Atmospheric Boundary Layer within and above a Mature Corn Canopy. Part I: Statistics and Energy Flux

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    Particle image velocimetry (PIV) measurements just within and above a mature corn canopy have been performed to clarify the small-scale spatial structure of the turbulence. The smallest resolved scales are about 15 times the Kolmogorov length scale (ν\nu \approx 0.4 mm), the Taylor microscales are about 100ν100\nu, and the Taylor scale Reynolds numbers range between Rλ=2000R_{\lambda} =2000 and 3000. The vertical profiles of mean flow and turbulence parameters match those found in previous studies. Frequency spectra, obtained using the data as time series, are combined with instantaneous spatial spectra to resolve more than five orders of magnitude of length scales. They display an inertial range spanning three decades. However, the small-scale turbulence in the dissipation range exhibits anisotropy at all measurement heights, in spite of apparent agreement with conditions for reaching local isotropy, following a high-Reynolds-number wind tunnel study. Directly calculated subgrid-scale (SGS) energy flux, determined by spatially filtering the PIV data, increases significantly with decreasing filter size, providing support for the existence of a spectral shortcut that bypasses the cascading process and injects energy directly into small scales. The highest measured SGS flux is about 40% of the estimated energy cascading rate as determined from a -5/3 fit to the spectra. Terms appearing in the turbulent kinetic energy budget that can be calculated from the PIV data are in agreement with previous results. Evidence of a very strong correlation between dissipation rate and out-of-plane component of the vorticity is demonstrated by a striking similarity between their time series. 1. Introductio

    Entanglement between Demand and Supply in Markets with Bandwagon Goods

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    Whenever customers' choices (e.g. to buy or not a given good) depend on others choices (cases coined 'positive externalities' or 'bandwagon effect' in the economic literature), the demand may be multiply valued: for a same posted price, there is either a small number of buyers, or a large one -- in which case one says that the customers coordinate. This leads to a dilemma for the seller: should he sell at a high price, targeting a small number of buyers, or at low price targeting a large number of buyers? In this paper we show that the interaction between demand and supply is even more complex than expected, leading to what we call the curse of coordination: the pricing strategy for the seller which aimed at maximizing his profit corresponds to posting a price which, not only assumes that the customers will coordinate, but also lies very near the critical price value at which such high demand no more exists. This is obtained by the detailed mathematical analysis of a particular model formally related to the Random Field Ising Model and to a model introduced in social sciences by T C Schelling in the 70's.Comment: Updated version, accepted for publication, Journal of Statistical Physics, online Dec 201

    The Generalized Green-Schwarz Mechanism for Type IIB Orientifolds with D3- and D7-Branes

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    In this paper, we work out in detail the tadpole cancellation conditions as well as the generalized Green-Schwarz mechanism for type IIB orientifold compactifications with D3- and D7-branes. We find that not only the well-known D3- and D7-tadpole conditions have to be satisfied, but in general also the vanishing of the induced D5-brane charges leads to a non-trivial constraint. In fact, for the case h1,10h^{1,1}_{-} \neq 0 the latter condition is important for the cancellation of chiral anomalies. We also extend our analysis by including D9- as well as D5-branes and determine the rules for computing the chiral spectrum of the combined system.Comment: 33+7 pages; 2 figures; v2: references added; v3: published versio

    Bounds on masses of bulk fields in string compactifications

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    In string compactification on a manifold X, in addition to the string scale and the normal scales of low-energy particle physics, there is a Kaluza-Klein scale 1/R associated with the size of X. We present an argument that generic string models with low-energy supersymmetry have, after moduli stabilization, bulk fields with masses which are parametrically lighter than 1/R. We discuss the implications of these light states for anomaly mediation and gaugino mediation scenarios.Comment: 15 page

    Phosphoethanolamine Transferase LptA in Haemophilus ducreyi Modifies Lipid A and Contributes to Human Defensin Resistance In Vitro

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    Haemophilus ducreyi resists the cytotoxic effects of human antimicrobial peptides (APs), including α-defensins, β-defensins, and the cathelicidin LL-37. Resistance to LL-37, mediated by the sensitive to antimicrobial peptide (Sap) transporter, is required for H. ducreyi virulence in humans. Cationic APs are attracted to the negatively charged bacterial cell surface. In other gram-negative bacteria, modification of lipopolysaccharide or lipooligosaccharide (LOS) by the addition of positively charged moieties, such as phosphoethanolamine (PEA), confers AP resistance by means of electrostatic repulsion. H. ducreyi LOS has PEA modifications at two sites, and we identified three genes (lptA, ptdA, and ptdB) in H. ducreyi with homology to a family of bacterial PEA transferases. We generated non-polar, unmarked mutants with deletions in one, two, or all three putative PEA transferase genes. The triple mutant was significantly more susceptible to both α- and β-defensins; complementation of all three genes restored parental levels of AP resistance. Deletion of all three PEA transferase genes also resulted in a significant increase in the negativity of the mutant cell surface. Mass spectrometric analysis revealed that LptA was required for PEA modification of lipid A; PtdA and PtdB did not affect PEA modification of LOS. In human inoculation experiments, the triple mutant was as virulent as its parent strain. While this is the first identified mechanism of resistance to α-defensins in H. ducreyi, our in vivo data suggest that resistance to cathelicidin LL-37 may be more important than defensin resistance to H. ducreyi pathogenesis

    Anomaly Mediated Supersymmetry Breaking without R-Parity

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    We analyze the low energy features of a supersymmetric standard model where the anomaly--induced contributions to the soft parameters are dominant in a scenario with bilinear RR--parity violation. This class of models leads to mixings between the standard model particles and supersymmetric ones which change the low energy phenomenology and searches for supersymmetry. In addition, RR--parity violation interactions give rise to small neutrino masses which we show to be consistent with the present observations.Comment: 38 pages, 15 figures. For higher resolution figures go to http://www.fma.if.usp.br/~magro/figures
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