1,056 research outputs found
From Correlators to Wilson Loops in Chern-Simons Matter Theories
We study n-point correlation functions for chiral primary operators in three
dimensional supersymmetric Chern-Simons matter theories. Our analysis is
carried on in N=2 superspace and covers N=2,3 supersymmetric CFT's, the N=6
ABJM and the N=8 BLG models. In the limit where the positions of adjacent
operators become light-like, we find that the one-loop n-point correlator
divided by its tree level expression coincides with a light-like n-polygon
Wilson loop. Remarkably, the result can be simply expressed as a linear
combination of five dimensional two-mass easy boxes. We manage to evaluate the
integrals analytically and find a vanishing result, in agreement with previous
findings for Wilson loops.Comment: 32 pages, 6 figures, JHEP
A preliminary census of the macrofungi of Mt Wellington, Tasmania- the sequestrate species
This is the fourth and final contribution in a series of papers providing a preliminary documentation of the macrofungi of Mt Wellington, Tasmania. The earlier papers dealt with the gilled Basidiomycota, the non-gilled Basidiomycota and the Ascomycota, respectively, excluding the sequestrate species. The present paper completes the series by dealing with the sequestrate species, of which seven Ascomycota, 76 Basidiomycota, three Glomeromycota and one Zygomycota were found. Seven new genera and 25 new species to be formally described elsewhere, are recorded
On form factors in N=4 sym
In this paper we study the form factors for the half-BPS operators
and the stress tensor supermultiplet
current up to the second order of perturbation theory and for the
Konishi operator at first order of perturbation theory in
SYM theory at weak coupling. For all the objects we observe the
exponentiation of the IR divergences with two anomalous dimensions: the cusp
anomalous dimension and the collinear anomalous dimension. For the IR finite
parts we obtain a similar situation as for the gluon scattering amplitudes,
namely, apart from the case of and the finite part has
some remainder function which we calculate up to the second order. It involves
the generalized Goncharov polylogarithms of several variables. All the answers
are expressed through the integrals related to the dual conformal invariant
ones which might be a signal of integrable structure standing behind the form
factors.Comment: 35 pages, 7 figures, LATEX2
Water dispersible microbicidal cellulose acetate phthalate film
BACKGROUND: Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. METHODS: CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. RESULTS: The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. CONCLUSIONS: Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP
Probing empirical contact networks by simulation of spreading dynamics
Disease, opinions, ideas, gossip, etc. all spread on social networks. How
these networks are connected (the network structure) influences the dynamics of
the spreading processes. By investigating these relationships one gains
understanding both of the spreading itself and the structure and function of
the contact network. In this chapter, we will summarize the recent literature
using simulation of spreading processes on top of empirical contact data. We
will mostly focus on disease simulations on temporal proximity networks --
networks recording who is close to whom, at what time -- but also cover other
types of networks and spreading processes. We analyze 29 empirical networks to
illustrate the methods
Extremal Multicenter Black Holes: Nilpotent Orbits and Tits Satake Universality Classes
Four dimensional supergravity theories whose scalar manifold is a symmetric
coset manifold U[D=4]/Hc are arranged into a finite list of Tits Satake
universality classes. Stationary solutions of these theories, spherically
symmetric or not, are identified with those of an euclidian three-dimensional
sigma-model, whose target manifold is a Lorentzian coset U[D=3]/H* and the
extremal ones are associated with H* nilpotent orbits in the K* representation
emerging from the orthogonal decomposition of the algebra U[D=3] with respect
to H*. It is shown that the classification of such orbits can always be reduced
to the Tits-Satake projection and it is a class property of the Tits Satake
universality classes. The construction procedure of Bossard et al of extremal
multicenter solutions by means of a triangular hierarchy of integrable
equations is completed and converted into a closed algorithm by means of a
general formula that provides the transition from the symmetric to the solvable
gauge. The question of the relation between H* orbits and charge orbits W of
the corresponding black holes is addressed and also reduced to the
corresponding question within the Tits Satake projection. It is conjectured
that on the vanishing locus of the Taub-NUT current the relation between
H*-orbit and W-orbit is rigid and one-to-one. All black holes emerging from
multicenter solutions associated with a given H* orbit have the same W-type.
For the S^3 model we provide a complete survey of its multicenter solutions
associated with all of the previously classified nilpotent orbits of sl(2) x
sl(2) within g[2,2]. We find a new intrinsic classification of the W-orbits of
this model that might provide a paradigm for the analogous classification in
all the other Tits Satake universality classes.Comment: 83 pages, LaTeX; v2: few misprints corrected and references adde
Fractal analyses reveal independent complexity and predictability of gait
Locomotion is a natural task that has been assessed for decades and used as a proxy to highlight impairments of various origins. So far, most studies adopted classical linear analyses of spatio-temporal gait parameters. Here, we use more advanced, yet not less practical, non-linear techniques to analyse gait time series of healthy subjects. We aimed at finding more sensitive indexes related to spatio-temporal gait parameters than those previously used, with the hope to better identify abnormal locomotion. We analysed large-scale stride interval time series and mean step width in 34 participants while altering walking direction (forward vs. backward walking) and with or without galvanic vestibular stimulation. The Hurst exponent α and the Minkowski fractal dimension D were computed and interpreted as indexes expressing predictability and complexity of stride interval time series, respectively. These holistic indexes can easily be interpreted in the framework of optimal movement complexity. We show that α and D accurately capture stride interval changes in function of the experimental condition. Walking forward exhibited maximal complexity (D) and hence, adaptability. In contrast, walking backward and/or stimulation of the vestibular system decreased D. Furthermore, walking backward increased predictability (α) through a more stereotyped pattern of the stride interval and galvanic vestibular stimulation reduced predictability. The present study demonstrates the complementary power of the Hurst exponent and the fractal dimension to improve walking classification. Our developments may have immediate applications in rehabilitation, diagnosis, and classification procedures
The effect of arm training on thermoregulatory responses and calf volume during upper body exercise
The final publication is available at Springer via https://doi.org/10.1007/s00421-014-2842-9.PURPOSE: The smaller muscle mass of the upper body compared to the lower body may elicit a smaller thermoregulatory stimulus during exercise and thus produce novel training-induced thermoregulatory adaptations. Therefore, the principal aim of the study was to examine the effect of arm training on thermoregulatory responses during submaximal exercise. METHODS: Thirteen healthy male participants (Mean ± SD age 27.8 ± 5.0 years, body mass 74.8 ± 9.5 kg) took part in 8 weeks of arm crank ergometry training. Thermoregulatory and calf blood flow responses were measured during 30 min of arm cranking at 60% peak power (W peak) pre-, and post-training and post-training at the same absolute intensity as pre-training. Core temperature and skin temperatures were measured, along with heat flow at the calf, thigh, upper arm and chest. Calf blood flow using venous occlusion plethysmography was performed pre- and post-exercise and calf volume was determined during exercise. RESULTS: The upper body training reduced aural temperature (0.1 ± 0.3 °C) and heat storage (0.3 ± 0.2 J g(-1)) at a given power output as a result of increased whole body sweating and heat flow. Arm crank training produced a smaller change in calf volume post-training at the same absolute exercise intensity (-1.2 ± 0.8% compared to -2.2 ± 0.9% pre-training; P < 0.05) suggesting reduced leg vasoconstriction. CONCLUSION: Training improved the main markers of aerobic fitness. However, the results of this study suggest arm crank training additionally elicits physiological responses specific to the lower body which may aid thermoregulation.Peer reviewedFinal Accepted Versio
Cosmic Ray Anomalies from the MSSM?
The recent positron excess in cosmic rays (CR) observed by the PAMELA
satellite may be a signal for dark matter (DM) annihilation. When these
measurements are combined with those from FERMI on the total () flux
and from PAMELA itself on the ratio, these and other results are
difficult to reconcile with traditional models of DM, including the
conventional mSUGRA version of Supersymmetry even if boosts as large as
are allowed. In this paper, we combine the results of a previously
obtained scan over a more general 19-parameter subspace of the MSSM with a
corresponding scan over astrophysical parameters that describe the propagation
of CR. We then ascertain whether or not a good fit to this CR data can be
obtained with relatively small boost factors while simultaneously satisfying
the additional constraints arising from gamma ray data. We find that a specific
subclass of MSSM models where the LSP is mostly pure bino and annihilates
almost exclusively into pairs comes very close to satisfying these
requirements. The lightest in this set of models is found to be
relatively close in mass to the LSP and is in some cases the nLSP. These models
lead to a significant improvement in the overall fit to the data by an amount
dof in comparison to the best fit without Supersymmetry
while employing boosts . The implications of these models for future
experiments are discussed.Comment: 57 pages, 31 figures, references adde
Thermally stable single atom Pt/m-Al2O3 for selective hydrogenation and CO oxidation
Single-atom metal catalysts offer a promising way to utilize precious noble metal elements more effectively, provided that they are catalytically active and sufficiently stable. Herein, we report a synthetic strategy for Pt single-atom catalysts with outstanding stability in several reactions under demanding conditions. The Pt atoms are firmly anchored in the internal surface of mesoporous Al2O3, likely stabilized by coordinatively unsaturated pentahedral Al3+ centres. The catalyst keeps its structural integrity and excellent performance for the selective hydrogenation of 1,3-butadiene after exposure to a reductive atmosphere at 200 °C for 24 h. Compared to commercial Pt nanoparticle catalyst on Al2O3 and control samples, this system exhibits significantly enhanced stability and performance for n-hexane hydro-reforming at 550 °C for 48 h, although agglomeration of Pt single-atoms into clusters is observed after reaction. In CO oxidation, the Pt single-atom identity was fully maintained after 60 cycles between 100 and 400 °C over a one-month period
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