3,974 research outputs found
Pion-kaon femtoscopy in PbPb collisions at TeV measured with ALICE
Femtoscopic correlations between charged pions and kaons for different charge
combinations are measured in PbPb collisions at TeV
with ALICE at the LHC. The three-dimensional pion-kaon ()
correlation functions and double ratios in the out-side-long pair rest frame
are studied in different centrality bins. The femtoscopic source
size parameter () and emission asymmetry () are
extracted. It is observed that the average source size of the system and the
emission asymmetry between pions and kaons increase from peripheral to central
events.Comment: 4 pages, 4 figures, Proceedings of XXVIIth International Conference
on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2018
Non-identical particle femtoscopy in PbPb collisions at TeV measured with ALICE
Two-particle femtoscopic correlations between non-identical charged particles
for different charge combinations are measured in Pb-Pb collisions at
= 2.76 TeV with ALICE at the LHC. The three-dimensional
two-particle correlation functions are studied in different centrality bins.
The femtoscopic source size parameter () and emission asymmetry
() are extracted. It is observed that the average source size of the
system and emission asymmetry between particles increase from peripheral to
central events.Comment: 3 pages, 2 figures, Proceedings of XXXIX International Conference on
High Energy Physics (ICHEP 2018
DistancePPG: Robust non-contact vital signs monitoring using a camera
Vital signs such as pulse rate and breathing rate are currently measured
using contact probes. But, non-contact methods for measuring vital signs are
desirable both in hospital settings (e.g. in NICU) and for ubiquitous in-situ
health tracking (e.g. on mobile phone and computers with webcams). Recently,
camera-based non-contact vital sign monitoring have been shown to be feasible.
However, camera-based vital sign monitoring is challenging for people with
darker skin tone, under low lighting conditions, and/or during movement of an
individual in front of the camera. In this paper, we propose distancePPG, a new
camera-based vital sign estimation algorithm which addresses these challenges.
DistancePPG proposes a new method of combining skin-color change signals from
different tracked regions of the face using a weighted average, where the
weights depend on the blood perfusion and incident light intensity in the
region, to improve the signal-to-noise ratio (SNR) of camera-based estimate.
One of our key contributions is a new automatic method for determining the
weights based only on the video recording of the subject. The gains in SNR of
camera-based PPG estimated using distancePPG translate into reduction of the
error in vital sign estimation, and thus expand the scope of camera-based vital
sign monitoring to potentially challenging scenarios. Further, a dataset will
be released, comprising of synchronized video recordings of face and pulse
oximeter based ground truth recordings from the earlobe for people with
different skin tones, under different lighting conditions and for various
motion scenarios.Comment: 24 pages, 11 figure
Parallel versus off-pathway Michaelis-Menten mechanism for single-enzyme kinetics of a fluctuating enzyme
Recent fluorescence spectroscopy measurements of the turnover time
distribution of single-enzyme turnover kinetics of -galactosidase
provide evidence of Michaelis-Menten kinetics at low substrate concentration.
However, at high substrate concentrations, the dimensionless variance of the
turnover time distribution shows systematic deviations from the
Michaelis-Menten prediction. This difference is attributed to conformational
fluctuations in both the enzyme and the enzyme-substrate complex and to the
possibility of both parallel and off-pathway kinetics. Here, we use the
chemical master equation to model the kinetics of a single fluctuating enzyme
that can yield a product through either parallel or off-pathway mechanisms. An
exact expression is obtained for the turnover time distribution from which the
mean turnover time and randomness parameters are calculated. The parallel and
off-pathway mechanisms yield strikingly different dependences of the mean
turnover time and the randomness parameter on the substrate concentration. In
the parallel mechanism, the distinct contributions of enzyme and
enzyme-substrate fluctuations are clearly discerned from the variation of the
randomness parameter with substrate concentration. From these general results
we conclude that an off-pathway mechanism, with substantial enzyme-substrate
fluctuations, is needed to rationalize the experimental findings of
single-enzyme turnover kinetics of -galactosidase.Comment: 27 pages, 5 figure
An Examination of the Maturity Effect in the Indian Commodities Futures Market
This paper has examined the Samuelson’s hypothesis which states that the price volatility increases as the contract nears its maturity. It has also examined the BCSS hypothesis which provides that negative covariance between the spot price and net cost of carry explains the maturity effect. The study has examined these hypotheses on the data for wheat and pepper futures contract traded at NCDEX from the date of listing of the contract to 31st March 2007 and the maturity effect has been examined for each contract individually. The study has indicated that maturity effect is present in around 45 per cent of the wheat and pepper contracts. Evidence supporting the BCSS hypothesis is present more strongly in the case of wheat as compared to pepper and 79 per cent of the contracts having maturity effect have depicted negative covariance in the case of wheat. Thus, it can be concluded that maturity effect is present and it is explained to a large extent by the negative co-variance between spot price and net carry cost. The study has observed that there is further scope for research in this area in relation to other agricultural commodities and also metals. Further studies can also be undertaken to find the informational efficiency and the reaction of informational flow to identify the reasons for the presence or absence of maturity effect.Agricultural and Food Policy,
New physics solutions for and
Recent measurements of have reduced tension with the Standard Model
prediction. Taking all the present data into account, we obtain the values of
the Wilson coefficients of each new physics four-fermion operator of a given
Lorentz structure. We find that the combined data rule out most of the
solutions based on scalar/pseudoscalar operators. By studying the
inter-relations between different solutions, we find that there are only four
allowed solutions, which are based on operators with , linear
combination of and , tensor and linear combination of
scalar/pseudoscalar and tensor structure. We demonstrate that the need for new
physics is driven by those measurement of and where the
lepton is not studied. Further, we show that new physics only in is not compatible with the full set of observables in the
decays and .Comment: 16 pages, 1 figure (Accepted for publication in JHEP
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