5,602 research outputs found
Multiplicativity of completely bounded -norms implies a strong converse for entanglement-assisted capacity
The fully quantum reverse Shannon theorem establishes the optimal rate of
noiseless classical communication required for simulating the action of many
instances of a noisy quantum channel on an arbitrary input state, while also
allowing for an arbitrary amount of shared entanglement of an arbitrary form.
Turning this theorem around establishes a strong converse for the
entanglement-assisted classical capacity of any quantum channel. This paper
proves the strong converse for entanglement-assisted capacity by a completely
different approach and identifies a bound on the strong converse exponent for
this task. Namely, we exploit the recent entanglement-assisted "meta-converse"
theorem of Matthews and Wehner, several properties of the recently established
sandwiched Renyi relative entropy (also referred to as the quantum Renyi
divergence), and the multiplicativity of completely bounded -norms due to
Devetak et al. The proof here demonstrates the extent to which the Arimoto
approach can be helpful in proving strong converse theorems, it provides an
operational relevance for the multiplicativity result of Devetak et al., and it
adds to the growing body of evidence that the sandwiched Renyi relative entropy
is the correct quantum generalization of the classical concept for all
.Comment: 21 pages, final version accepted for publication in Communications in
Mathematical Physic
Privacy Issues of the W3C Geolocation API
The W3C's Geolocation API may rapidly standardize the transmission of
location information on the Web, but, in dealing with such sensitive
information, it also raises serious privacy concerns. We analyze the manner and
extent to which the current W3C Geolocation API provides mechanisms to support
privacy. We propose a privacy framework for the consideration of location
information and use it to evaluate the W3C Geolocation API, both the
specification and its use in the wild, and recommend some modifications to the
API as a result of our analysis
THE DISTINCT IMPACT OF FOOD STAMPS ON FOOD SPENDING
The Southworth hypothesis predicts that inframarginal food stamp recipients should choose the same bundle of goods, whether they receive coupons or cash. Empirical research has contradicted this prediction. Here, we present a model that retains some attractive features of the Southworth hypothesis, while relaxing the key assumption that appears to be incorrect. In particular, we allow different forms of benefits to have distinct effects on desired, or unrestricted food spending. Two categories of previously commonly used empirical models are evaluated as special cases of our more general model. We estimate this model using data from two cash-out experiments.Consumer/Household Economics, Food Security and Poverty,
Recovery of Polyphenols from Brewer’s Spent Grains
peer-reviewedThe recovery of antioxidant polyphenols from light, dark and mix brewer’s spent grain (BSG) using conventional maceration, microwave and ultrasound assisted extraction was investigated. Total polyphenols were measured in the crude (60% acetone), liquor extracts (saponified with 0.75% NaOH) and in their acidified ethyl acetate (EtOAc) partitioned fractions both by spectrophotometry involving Folin–Ciocalteu reagent and liquid-chromatography-tandem mass spectrometry (LC-MS/MS) methods. Irrespective of the extraction methods used, saponification of BSG yielded higher polyphenols than in the crude extracts. The EtOAc fractionations yielded the highest total phenolic content (TPC) ranging from 3.01 ± 0.19 to 4.71 ± 0.28 mg gallic acid equivalent per g of BSG dry weight. The corresponding total polyphenols quantified by LC-MS/MS ranged from 549.9 ± 41.5 to 2741.1 ± 5.2 µg/g of BSG dry weight. Microwave and ultrasound with the parameters and equipment used did not improve the total polyphenol yield when compared to the conventional maceration method. Furthermore, the spectrophotometric quantification of the liquors overestimated the TPC, while the LC-MS/MS quantification gave a closer representation of the total polyphenols in all the extracts. The total polyphenols were in the following order in the EtOAc fractions: BSG light > BSG Mix > BSG dark, and thus suggested BSG light as a sustainable, low cost source of natural antioxidants that may be tapped for applications in food and phytopharmaceutical industries
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A combined experimental-numerical study to tensile behaviour of limestone
In this paper, a combined experimental-computational study of double-edge notched stone specimen subject to cyclic tensile loading is presented. In the experimental part, the load-deformation response and the local displacement field are recorded. Both experimental results are used to validate a numerical model for the description of fracture within finite elements. The model uses displacement discontinuities to model cracks. These discontinuities are implemented using the partition of unity property of finite element shape functions. In the discontinuity, a combined damage-plasticity cohesive law is used. Numerical simulations are compared with experimental observations
THE EFFECT ON DIETARY QUALITY OF PARTICIPATION IN THE FOOD STAMP AND WIC PROGRAMS
Participants in the Food Stamp Program consume more meats, added sugars, and total fats than they would in the absence of the program, while their consumption of fruits, vegetables, grains, and dairy products stays about the same. Participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) consume significantly less added sugars, which may reflect the substitution of WIC-supplied juices and cereals in place of higher sugar soft drinks and cereals. These findings come from a study of low-income Americans using the Continuing Survey of Food Intake by Individuals.Nutrition assistance programs, food intake, dietary quality, Continuing Survey of Food Intake by Individuals (CSFII), Food Consumption/Nutrition/Food Safety, Food Security and Poverty,
Quantum discord and classical correlation can tighten the uncertainty principle in the presence of quantum memory
Uncertainty relations capture the essence of the inevitable randomness
associated with the outcomes of two incompatible quantum measurements.
Recently, Berta et al. have shown that the lower bound on the uncertainties of
the measurement outcomes depends on the correlations between the observed
system and an observer who possesses a quantum memory. If the system is
maximally entangled with its memory, the outcomes of two incompatible
measurements made on the system can be predicted precisely. Here, we obtain a
new uncertainty relation that tightens the lower bound of Berta et al., by
incorporating an additional term that depends on the quantum discord and the
classical correlations of the joint state of the observed system and the
quantum memory. We discuss several examples of states for which our new lower
bound is tighter than the bound of Berta et al. On the application side, we
discuss the relevance of our new inequality for the security of quantum key
distribution and show that it can be used to provide bounds on the distillable
common randomness and the entanglement of formation of bipartite quantum
states.Comment: v1: Latex, 4 and half pages, one fig; v2: 9 pages including 4-page
appendix; v3: accepted into Physical Review A with minor change
Towards a Microscopic Theory for Metallic Heavy-Fermion Point Contacts
The bias-dependent resistance R(V) of NS-junctions is calculated using the
Keldysh formalism in all orders of the transfer matrix element. We present a
compact and simple formula for the Andreev current, that results from the
coupling of electrons and holes on the normal side via the anomalous Green's
function on the superconducting side. Using simple BCS Nambu-Green's functions
the well known Blonder-Tinkam-Klapwijk theory can be recovered. Incorporating
the energy-dependent quasi-particle lifetime of the heavy fermions strongly
reduces the Andreev-reflection signal.Comment: 3 pages, TeX type, 1 eps figure include, SCES96 Z\"uric
Geothermal probabilistic cost study
A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model was used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents was analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance were examined
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