1,425 research outputs found
Dynamical estimates of chaotic systems from Poincar\'e recurrences
We show that the probability distribution function that best fits the
distribution of return times between two consecutive visits of a chaotic
trajectory to finite size regions in phase space deviates from the exponential
statistics by a small power-law term, a term that represents the deterministic
manifestation of the dynamics, which can be easily experimentally detected and
theoretically estimated. We also provide simpler and faster ways to calculate
the positive Lyapunov exponents and the short-term correlation function by
either realizing observations of higher probable returns or by calculating the
eigenvalues of only one very especial unstable periodic orbit of low-period.
Finally, we discuss how our approaches can be used to treat data coming from
complex systems.Comment: subm. for publication. Accepted fpr publication in Chao
Simulation of a Dripping Faucet
We present a simulation of a dripping faucet system. A new algorithm based on
Lagrangian description is introduced. The shape of drop falling from a faucet
obtained by the present algorithm agrees quite well with experimental
observations. Long-term behavior of the simulation can reproduce period-one,
period-two, intermittent and chaotic oscillations widely observed in
experiments. Possible routes to chaos are discussed.Comment: 20 pages, 15 figures, J. Phys. Soc. Jpn. (in press
Dripping Faucet Dynamics Clarified by an Improved Mass-Spring Model
An improved mass-spring model for a dripping faucet is presented. The model
is constructed based on the numerical results which we recently obtained from
fluid dynamical calculations. Both the fluid dynamical calculations and the
present mass-spring model exhibit a variety of complex behavior including
transition to chaos in good agreement with experiments. Further, the
mass-spring model reveals fundamental dynamics inherent in the dripping faucet
system.Comment: 17 pages, 17 figure
Dark Matter Results from 100 Live Days of XENON100 Data
We present results from the direct search for dark matter with the XENON100
detector, installed underground at the Laboratori Nazionali del Gran Sasso of
INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg
liquid xenon target. Interaction vertex reconstruction in three dimensions with
millimeter precision allows to select only the innermost 48 kg as ultra-low
background fiducial target. In 100.9 live days of data, acquired between
January and June 2010, no evidence for dark matter is found. Three candidate
events were observed in a pre-defined signal region with an expected background
of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter
interactions today, excluding spin-independent elastic WIMP-nucleon scattering
cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90%
confidence level.Comment: 5 pages, 5 figures; matches accepted versio
Implications on Inelastic Dark Matter from 100 Live Days of XENON100 Data
The XENON100 experiment has recently completed a dark matter run with 100.9
live-days of data, taken from January to June 2010. Events in a 48kg fiducial
volume in the energy range between 8.4 and 44.6 keVnr have been analyzed. A
total of three events have been found in the predefined signal region,
compatible with the background prediction of (1.8 \pm 0.6) events. Based on
this analysis we present limits on the WIMP-nucleon cross section for inelastic
dark matter. With the present data we are able to rule out the explanation for
the observed DAMA/LIBRA modulation as being due to inelastic dark matter
scattering off iodine at a 90% confidence level.Comment: 3 pages, 3 figure
Personal solar ultraviolet radiation dosimetry in an\ua0occupational setting across Europe
Background: Work-related solar ultraviolet radiation (UVR) is an important factor in the pathogenesis of non-melanoma skin cancer (NMSC). The World Health Organization, through the International Agency for Research on Cancer, has classified solar UVR as a group 1 carcinogen since 2012. The main problems encountered so far in the study of occupationally induced skin cancer include the lack of accurate occupational UVR dosimetry as well as insufficient distinction between occupational and leisure UVR exposure and underreporting of NMSC. Objectives: The aim of this study was to collect long-term individual UVR measurements in outdoor workers across European countries. Methods: A prospective study was initiated through the European Academy of Dermatology and Venereology, Healthy Skin@Work Campaign, measuring UVR exposure doses at occupational settings of masons from five European countries. Measurements were performed for several consecutive months using the GENESIS-UV measurement system. Results: The results identified alarming UVR exposure data. Average daily UVR doses ranged 148.40–680.48 J/m2 in Romania, 342.4–640.8 J/m2 in Italy, 165.5–466.2 J/m2 in Croatia, 41.8–473.8 J/m2 in Denmark and 88.15–400.22 J/m2 in Germany. Results showed an expected latitude dependence with increasing UVR yearly dosage from the north to the south of Europe. Conclusions: This study shows that outdoor workers from EU countries included in this study are exposed to high levels of occupational solar UVR, vastly exceeding the occupational exposure limits for solar UVR exposure, considered to be 1–1.33 SED/day in the period from May to September. This finding may serve as an evidence-based recommendation to authorities on implementing occupational skin cancer prevention strategies
Comment on "On the subtleties of searching for dark matter with liquid xenon detectors"
In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that
XENON100's upper limits on spin-independent WIMP-nucleon cross sections for
WIMP masses below 10 GeV "may be understated by one order of magnitude or
more". Having performed a similar, though more detailed analysis prior to the
submission of our new result (arXiv:1207.5988), we do not confirm these
findings. We point out the rationale for not considering the described effect
in our final analysis and list several potential problems with his study.Comment: 3 pages, no figure
Rapid enhancer remodeling and transcription factor repurposing enable high magnitude gene induction upon acute activation of NK cells
During development, innate lymphocytes acquire defined sets of primed enhancers facilitating the rapid immune response. In this issue of Immunity, Sciumè et al. delineate the epigenetic changes occurring during acute NK cell activation, revealing the formation of de novo enhancers and repurposing of both lineage-determining and signal-regulated transcription factors
Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA
Inclusive photoproduction of D*+- mesons has been measured for photon-proton
centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality
Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of
37 pb^-1. Total and differential cross sections as functions of the D*
transverse momentum and pseudorapidity are presented in restricted kinematical
regions and the data are compared with next-to-leading order (NLO) perturbative
QCD calculations using the "massive charm" and "massless charm" schemes. The
measured cross sections are generally above the NLO calculations, in particular
in the forward (proton) direction. The large data sample also allows the study
of dijet production associated with charm. A significant resolved as well as a
direct photon component contribute to the cross section. Leading order QCD
Monte Carlo calculations indicate that the resolved contribution arises from a
significant charm component in the photon. A massive charm NLO parton level
calculation yields lower cross sections compared to the measured results in a
kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
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