1,654 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
Mitomycin resistance in mammalian cells expressing the bacterial mitomycin C resistance protein MCRA
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
The EEE Project
The new experiment ``Extreme Energy Events'' (EEE) to detect extensive air
showers through muon detection is starting in Italy. The use of particle
detectors based on Multigap Resistive Plate Chambers (MRPC) will allow to
determine with a very high accuracy the direction of the axis of cosmic ray
showers initiated by primaries of ultra-high energy, together with a high
temporal resolution. The installation of many of such 'telescopes' in numerous
High Schools scattered all over the Italian territory will also allow to
investigate coincidences between multiple primaries producing distant showers.
Here we present the experimental apparatus and its tasks.Comment: 4 pages, 29th ICRC 2005, Pune, Indi
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
Study of the effect of neutrino oscillation on the supernova neutrino signal with the LVD detector
We present an update of our previous study (astro-ph/0112312) on how
oscillations affect the signal from a supernova core collapse observed in the
LVD detector at LNGS. In this paper we use a recent, more precise determination
of the cross section (astro-ph/0302055) to calculate the expected number of
inverse beta decay events, we introduce in the simulation also the -{\rm
Fe} interactions, we include the Earth matter effects and, finally, we study
also the inverted mass hierarchy case.Comment: 4 pages, 4 figures, to appear in the Proceedings of ICRC 200
Application of an Ionic Liquid in the Microwave Assisted Extraction of Cytotoxic Metabolites from Fruits of Schinus terebinthifolius Raddi (Anacardiaceae)
This work reports the application of an ionic liquid (1-butyl-3-methylimidazolium bromide, BMImBr) in the microwave assisted extraction (MAE) of metabolites from fruits of Schinus terebinthifolius. Dried fruits were individually extracted using BMImBr: H2O 1: 1, v/v (experiment 1) and pure H2O (experiment 2) by MAE (10 min at 60 degrees C). After partition using EtOAc, the yield to experiment 1 was about 23% while to experiment 2 was 0.1%. The EtOAc fraction obtained from experiment 1 was purified by chromatographic methods to afford 3-oxotirucalla-7,24Z-dien27- oic acid, 3a-hydroxytirucalla-7,24Z-dien-27-oic acid, 3 alpha-acetoxytirucalla-7,24Z-dien-27-oic acid, gallic acid, and ethyl gallate, being the first occurrence of the third compound as natural product. Cytotoxic activity was evaluated in vitro against cancer cell lines (A2058, HeLa, SiHa, HCT, SKBR-3, U87, and B16F2Nex2), being 3 alpha-acetoxytirucalla-7,24Z-dien-27-oic acid the more active metabolite with IC50 ranging from 10.9 +/- 1.3 to 17.3 +/- 1.4 mu g mL(-1), lower than that determined to positive control cisplatin.FAPESPCAPESCNPqInstituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo (UNIFESP), 09972-270 Diadema-SP, BrazilDepartamento de Micro, Imuno e Parasitologia, Universidade Federal de São Paulo (UNIFESP), 04023-062 São Paulo-SP, BrazilInstituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo (UNIFESP), 09972-270 Diadema-SP, BrazilDepartamento de Micro, Imuno e Parasitologia, Universidade Federal de São Paulo (UNIFESP), 04023-062 São Paulo-SP, BrazilFAPESP: BIOTA 2011/51739-6FAPESP: 2015/11936-2Web of Scienc
First CNGS events detected by LVD
The CERN Neutrino to Gran Sasso (CNGS) project aims to produce a high energy,
wide band beam at CERN and send it toward the INFN Gran Sasso
National Laboratory (LNGS), 732 km away. Its main goal is the observation of
the appearance, through neutrino flavour oscillation. The beam
started its operation in August 2006 for about 12 days: a total amount of
protons were delivered to the target. The LVD detector, installed
in hall A of the LNGS and mainly dedicated to the study of supernova neutrinos,
was fully operating during the whole CNGS running time. A total number of 569
events were detected in coincidence with the beam spill time. This is in good
agreement with the expected number of events from Montecarlo simulations.Comment: Accepted for publication by the European Physical Journal C ; 7
pages, 11 figure
On-line recognition of supernova neutrino bursts in the LVD detector
In this paper we show the capabilities of the Large Volume Detector (INFN
Gran Sasso National Laboratory) to identify a neutrino burst associated to a
supernova explosion, in the absence of an "external trigger", e.g., an optical
observation. We describe how the detector trigger and event selection have been
optimized for this purpose, and we detail the algorithm used for the on-line
burst recognition. The on-line sensitivity of the detector is defined and
discussed in terms of supernova distance and electron anti-neutrino intensity
at the source.Comment: Accepted for pubblication on Astroparticle Physics. 13 pages, 10
figure
Search for low energy neutrinos in correlation with the 8 events observed by the EXPLORER and NAUTILUS detectors in 2001
We report on a search for low-energy neutrino (antineutrino) bursts in
correlation with the 8 time coincident events observed by the gravitational
waves detectors EXPLORER and NAUTILUS (GWD) during the year 2001. The search,
conducted with the LVD detector (INFN Gran Sasso National Laboratory, Italy),
has considered several neutrino reactions, corresponding to different neutrino
species, and a wide range of time intervals around the (GWD) observed events.
No evidence for statistically significant correlated signals in LVD has been
found. Assuming two different origins for neutrino emission, the cooling of a
neutron star from a core-collapse supernova or from coalescing neutron stars
and the accretion of shocked matter, and taking into account neutrino
oscillations, we derive limits to the total energy emitted in neutrinos and to
the amount of accreting mass, respectively.Comment: Accepted for publication in Astronomy and Astrophysic
- …