199,754 research outputs found
Model-checking branching-time properties of probabilistic automata and probabilistic one-counter automata
This paper studies the problem of model-checking of probabilistic automaton
and probabilistic one-counter automata against probabilistic branching-time
temporal logics (PCTL and PCTL). We show that it is undecidable for these
problems.
  We first show, by reducing to emptiness problem of probabilistic automata,
that the model-checking of probabilistic finite automata against branching-time
temporal logics are undecidable. And then, for each probabilistic automata, by
constructing a probabilistic one-counter automaton with the same behavior as
questioned probabilistic automata the undecidability of model-checking problems
against branching-time temporal logics are derived, herein.Comment: Comments are welcom
Neutrino Flavor Ratio on Earth and at Astrophysical Sources
We present the reconstruction of neutrino flavor ratios at astrophysical
sources. For distinguishing the pion source and the muon-damped source to the
3 level, the neutrino flux ratios,
 and
, need to be measured in accuracies better
than 10%.Comment: 3 pages, 8 figures. Talk presented by T.C. Liu in ERICE 2009, Sicily
Concrete: Potential material for Space Station
To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth
Leisure-time physical activity and circulating 25-hydroxyvitamin D levels in cancer survivors: A cross-sectional analysis using data from the US National Health and Nutrition Examination Survey
Objectives: Circulating 25-hydroxyvitamin D (25-OHD) is associated with improved cancer prognosis in some studies, yet it may be a surrogate marker for physical activity. We investigated the associations of leisure-time physical activity (LTPA) with circulating 25-OHD levels in cancer survivors, and determined whether associations differ by indoor and outdoor activity.
Design: Cross-sectional study.
Setting: The US National Health and Nutrition Examination Survey (NHANES).
Participants: Cancer survivors with available data on demographic information, measures of adiposity, smoking history, self-reported LTPA and circulating 25-OHD levels in five waves of NHANES (2001–2010).
Main outcomes measures: Circulating 25-OHD levels.
Results: Multivariable linear regression and logistic regression models were used to evaluate the associations of self-reported LTPA with 25-OHD, adjusting for potential confounders. Due to the differences in LTPA measure, the analyses were conducted separately for 2001–2006 and 2007–2010 data. We further estimated associations by indoor and outdoor activity in the 2001–2006 data. There were 1530 cancer survivors (mean age=60.5 years, mean body mass index=28.6 kg/m2). The prevalent cancer sites were breast (19.3%), prostate (18.8%), cervix (10.4%) and colon (8.6%). Compared with inactive cancer survivors, being physically active was associated with higher circulating 25-OHD levels (8.07 nmol/L, 95% CI 4.63 to 11.52) for 2001–2006 data. In the mutually adjusted model, higher outdoor activity (5.83 nmol/L, 95% CI 1.64 to 10.01), but not indoor activity (2.93 nmol/L, 95% CI −1.80 to 7.66), was associated with statistically significantly higher 25-OHD levels. The interaction between indoor and outdoor activities was, however, not significant (p=0.29). The only statistically significant association seen in the 2007–2010 data was among obese cancer survivors.
Conclusion: Physical activity, particularly outdoor activity, is associated with higher 25-OHD levels in cancer survivors. In view of the possible beneficial effects of vitamin D on cancer prognosis, engaging in outdoor physical activity could provide clinically meaningful increases in 25-OHD levels among cancer survivors
Andreev Edge State on Semi-Infinite Triangular Lattice: Detecting the Pairing Symmetry in Na_0.35CoO_2.yH_2O
We study the Andreev edge state on the semi-infinite triangular lattice with
different pairing symmetries and boundary topologies. We find a rich phase
diagram of zero energy Andreev edge states that is a unique fingerprint of each
of the possible pairing symmetries. We propose to pin down the pairing symmetry
in recently discovered Na_xCoO_2 material by the Fourier-transformed scanning
tunneling spectroscopy for the edge state. A surprisingly rich phase diagram is
found and explained by a general gauge argument and mapping to 1D tight-binding
model. Extensions of this work are discussed at the end.Comment: 4 pages, 1 table, 4 figure
On the Head and the Tail of the Colored Jones Polynomial
The colored Jones polynomial is a series of one variable Laurent polynomials
J(K,n) associated with a knot K in 3-space. We will show that for an
alternating knot K the absolute values of the first and the last three leading
coefficients of J(K,n) are independent of n when n is sufficiently large.
Computation of sample knots indicates that this should be true for any fixed
leading coefficient of the colored Jones polynomial for alternating knots. As a
corollary we get a Volume-ish Theorem for the colored Jones Polynomial.Comment: 14 pages, 6 figure
Media fusion and future TV: Examining multi-screen TV convergence in Singapore
This study examines Singapore's national media blueprint and industry stakeholders' coping strategies in response to multi-screen TV development. The findings show Singapore muti-screen TV development is still at a nascent stage after launching Media Fushion and FutureTV plans in mid 2009. The policymakers play a key role to follow national media blueprint to unify the inter-industry and cross-country collaboration. TV operators and telcos are found to remediate themselves by harnessing the power of internet and mobile technologies for content innovation and distribution. To tackle the complicated convergent issues in multi-screen TV industry, this study proposes to separately regulate the technology-neutral platforms and diverse audiovisual content. It also recommends a pro-innovative policy with the light-touch licensing scheme and loose content regulation to facilitate the development of the next TV. --three-screen TV,multi-screen TV,convergence,media fusion,IPTV,mobile TV,cross-platform,TV technologies,TV market,TV policy
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