72 research outputs found
Anomalous cross-modulation between microwave beams
Abstract An anomalous effect in the near field of crossing microwave beams, which consists of an unexpected transfer of modulation from one beam to the other, has found a plausible interpretation within the framework of a locally broken Lorentz invariance. A theoretical approach of this kind deserves to be reconsidered also in the light of further experimental work, including a counter-check of the phenomenon
Manifestations of Top Compositeness at Colliders
We explore the possibility that the right-handed top quark is composite,
identifying possible signatures of compositeness and how they might manifest
themselves at the LHC and Tevatron. We perform a complete analysis of the
dimension six modifications of the top coupling to gluons and find that
cancellations among operators in the t\bar{t} rate allow for very low
compositeness scales, but this can be drastically improved by looking at
kinematic distributions. Turning to the LHC, we examine four top production
from a dimension six four-top operator and estimate the LHC with 100 {\rm
fb}^{-1} collected luminosity to be sensitive to compositeness scales as high
as 5 TeV.Comment: 8 pages, 6 figures, updated figure 6, updated references, final
version published in JHE
Synthesis and Biological Evaluation of New Antitubulin Agents Containing 2-(3′,4′,5′-trimethoxyanilino)-3,6-disubstituted-4,5,6,7-tetrahydrothieno[2,3-c]pyridine Scaffold
Two novel series of compounds based on the 4,5,6,7-tetrahydrothieno[2,3-c]pyridine and 4,5,6,7-tetrahydrobenzo[b]thiophene molecular skeleton, characterized by the presence of a 3′,4′,5′-trimethoxyanilino moiety and a cyano or an alkoxycarbonyl group at its 2- or 3-position, respectively, were designed, synthesized, and evaluated for antiproliferative activity on a panel of cancer cell lines and for selected highly active compounds, inhibition of tubulin polymerization, and cell cycle effects. We have identified the 2-(3′,4′,5′-trimethoxyanilino)-3-cyano-6-methoxycarbonyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine derivative 3a and its 6-ethoxycarbonyl homologue 3b as new antiproliferative agents that inhibit cancer cell growth with IC50 values ranging from 1.1 to 4.7 μM against a panel of three cancer cell lines. Their interaction with tubulin at micromolar levels leads to the accumulation of cells in the G2/M phase of the cell cycle and to an apoptotic cell death. The cell apoptosis study found that compounds 3a and 3b were very effective in the induction of apoptosis in a dose-dependent manner. These two derivatives did not induce cell death in normal human peripheral blood mononuclear cells, suggesting that they may be selective against cancer cells. Molecular docking studies confirmed that the inhibitory activity of these molecules on tubulin polymerization derived from binding to the colchicine site
Sudakov resummation of multiparton QCD cross sections
We present the general expressions for the resummation, up to next-to-leading
logarithmic accuracy, of Sudakov-type logarithms in processes with an
arbirtrary number of hard-scattering partons. These results document the
formulae used by the authors in several previous phenomenological studies. The
resummation formulae presented here, which are valid for phase-space
factorizable observables, determine the resummation correction in a
process-independent fashion. All process dependence is encoded in the colour
and flavour structure of the leading order and virtual one-loop amplitudes, and
in Sudakov weights associated to the cross section kinematics. We explicitly
illustrate the application to the case of Drell--Yan and prompt-photon
production.Comment: 13 pages, LaTe
Hide and seek between Andromeda's halo, disk, and giant stream
Photometry in B, V (down to V ~ 26 mag) is presented for two 23' x 23' fields
of the Andromeda galaxy (M31) that were observed with the blue channel camera
of the Large Binocular Telescope during the Science Demonstration Time. Each
field covers an area of about 5.1kpc x 5.1kpc at the distance of M31 ((m-M)o ~
24.4 mag), sampling, respectively, a northeast region close to the M31 giant
stream (field S2), and an eastern portion of the halo in the direction of the
galaxy minor axis (field H1). The stream field spans a region that includes
Andromeda's disk and the giant stream, and this is reflected in the complexity
of the color magnitude diagram of the field. One corner of the halo field also
includes a portion of the giant stream. Even though these demonstration time
data were obtained under non-optimal observing conditions the B photometry,
acquired in time-series mode, allowed us to identify 274 variable stars (among
which 96 are bona fide and 31 are candidate RR Lyrae stars, 71 are Cepheids,
and 16 are binary systems) by applying the image subtraction technique to
selected portions of the observed fields. Differential flux light curves were
obtained for the vast majority of these variables. Our sample includes mainly
pulsating stars which populate the instability strip from the Classical
Cepheids down to the RR Lyrae stars, thus tracing the different stellar
generations in these regions of M31 down to the horizontal branch of the oldest
(t ~ 10 Gyr) component.Comment: 59 pages, 26 figures, 12 tables, ApJ in pres
Automation of one-loop QCD corrections
We present the complete automation of the computation of one-loop QCD
corrections, including UV renormalization, to an arbitrary scattering process
in the Standard Model. This is achieved by embedding the OPP integrand
reduction technique, as implemented in CutTools, into the MadGraph framework.
By interfacing the tool so constructed, which we dub MadLoop, with MadFKS, the
fully automatic computation of any infrared-safe observable at the
next-to-leading order in QCD is attained. We demonstrate the flexibility and
the reach of our method by calculating the production rates for a variety of
processes at the 7 TeV LHC.Comment: 64 pages, 12 figures. Corrected the value of m_Z in table 1. In table
2, corrected the values of cross sections in a.4 and a.5 (previously computed
with mu=mtop/2 rather than mu=mtop/4). In table 2, corrected the values of
NLO cross sections in b.3, b.6, c.3, and e.7 (the symmetry factor for a few
virtual channels was incorrect). In sect. A.4.3, the labeling of the
four-momenta was incorrec
Four tops on the real projective plane at LHC
We explore the four top signal ttbar ttbar at the 7 TeV Large Hadron Collider
as a probe of physics beyond the standard model. Enhancement of the
corresponding cross-section with respect to the Standard Model value can probe
the electroweak symmetry breaking sector or test extra dimensional models with
heavy Kaluza-Klein gluons and quarks. We perform a detailed analysis including
background and detector simulation in the specific case of a universal
extra-dimensional model with two extra dimensions compactified using the
geometry of the real projective plane. For masses around 600 GeV, a discovery
is possible for an effective cross section above 210 fb (36 fb) for 1/fb
(10/fb) of integrated luminosity. This implies a branching ratio in tops of the
(1,1) heavy photon above 13% (5%). Furthermore, the 4-top signal from the (2,0)
and (0,2) tiers can be discovered with an integrated luminosity of 3.5/fb. The
results of our simulation can be easily adapted to other models since the
background processes are identical. Concerning the signal, typical production
mechanisms for the ttbar ttbar signal are similar even if cross-section values
may vary considerably depending on the model and the spectrum of the new
particles.Comment: 26 pages, 4 figures, minor modifications and few references adde
Influenza vaccination coverage among medical residents: An Italian multicenter survey
Although influenza vaccination is recognized to be safe and effective, recent studies have confirmed that immunization coverage among health care workers remain generally low, especially among medical residents (MRs). Aim of the present multicenter study was to investigate attitudes and determinants associated with acceptance of influenza vaccination among Italian MRs. A survey was performed in 2012 on MRs attending post-graduate schools of 18 Italian Universities. Each participant was interviewed via an anonymous, self-administered, web-based questionnaire including questions on attitudes regarding influenza vaccination. A total of 2506 MRs were recruited in the survey and 299 (11.9%) of these stated they had accepted influenza vaccination in 2011-2012 season. Vaccinated MRs were older (P = 0.006), working in clinical settings (P = 0.048), and vaccinated in the 2 previous seasons (P < 0.001 in both seasons). Moreover, MRs who had recommended influenza vaccination to their patients were significantly more compliant with influenza vaccination uptake in 2011-2012 season (P < 0.001). "To avoid spreading influenza among patients" was recognized as the main reason for accepting vaccination by less than 15% of vaccinated MRs. Italian MRs seem to have a very low compliance with influenza vaccination and they seem to accept influenza vaccination as a habit that is unrelated to professional and ethical responsibility. Otherwise, residents who refuse vaccination in the previous seasons usually maintain their behaviors. Promoting correct attitudes and good practice in order to improve the influenza immunization rates of MRs could represent a decisive goal for increasing immunization coverage among health care workers of the future. © 2014 Landes Bioscience
Secular Trends in the Prevalence of Overweight and Obesity in Sicilian Schoolchildren Aged 11–13 Years During the Last Decade
The present study evaluates trends in the prevalence of overweight and obesity in relation to gender and area of residence between two cohorts of students aged 11–13 years in Sicily. The analysis was performed on 1,839 schoolchildren, with 924 and 915 children being studied in 1999–2001 and 2009–2010, respectively. The children who were enrolled during 2009–2010 had significantly higher body mass indexes (BMI), BMI z-scores, and waist circumferences than the children who were studied during 1999–2001 (p<0.0001 for all); these differences was also observed when the cohort was subdivided according to gender or residence area The prevalence of obesity increased significantly from 7.9% in 1999–2001 to 13.7% in 2009–2010 (p<0.0001), whereas thinness decreased significantly from 10.1% to 2.3% (p<0.0001) in the same periods. The increase of trends in the prevalence of obesity was significantly higher in males (9.7% vs. 17.6%, p = 0.0006) than in females (6.3% vs. 9.8%, p = 0.04) and was slightly higher in urban areas (8.8% vs. 14.3%, p = 0.002) than in rural areas (7.8% vs. 13.0%, p = 0.012). The male gender was associated with a higher risk of being overweight or obese (odds ratio: 1.63; 95% confidence intervals: 1.24–2.15; p = 0.0005) in 2009–2010 than in 1999–2001, after adjusting for age and the residence area. In conclusion, this study showed an increasing trend in the prevalence of overweight and obesity in Sicilian schoolchildren during the last decade and that this trend was related to gender, age and the area of residence. More specifically, our data indicated that the prevalence of obesity increased by 5.8%, the prevalence of thinness decreased by 7.8% and the prevalence of normal-weight children did not change over the course of a decade. These results suggest a shift in the body weights of Sicilian children toward the upper percentiles
W and Z/gamma* boson production in association with a bottom-antibottom pair
We present a study of l\nu b\bar{b} and l+ l- b\bar{b} production at hadron
colliders. Our results, accurate to the next-to-leading order in QCD, are based
on automatic matrix-element calculations performed by MadLoop and MadFKS, and
are given at both the parton level, and after the matching with the Herwig
event generator, achieved with aMC@NLO. We retain the complete dependence on
the bottom-quark mass, and include exactly all spin correlations of final-state
leptons. We discuss the cases of several observables at the LHC which highlight
the importance of accurate simulations.Comment: 18 pages, 12 figures. References updated, minor changes to the tex
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