2,572 research outputs found
Peroxisomes in intestinal and gallbladder epithelial cells of the stickleback, Gasterosteus aculeatus L. (Teleostei)
The occurrence of microbodies in the epithelial cells of the intestine and gallbladder of the stickleback, Gasterosteus aculeatus L., is described. In the intestine the organelles are predominantly located in the apical and perinuclear zone of the cells and may contain small crystalline cores. In gallbladder epithelial cells the microbodies are distributed randomly. The latter organdies are characterized by the presence of large crystalloids. Cytochemical and biochemical experiments show that catalase and D-amino acid oxidase are main matrix components of the microbodies in both the intestinal and gallbladder epithelia. These organelles therefore are considered peroxisomes. In addition, in intestinal mucosa but not in gallbladder epithelium a low activity of palmitoyl CoA oxidase was detected biochemically. Urate oxidase and L-α hydroxy acid oxidase activities could not be demonstrated.
A random quantum key distribution by using Bell states
We proposed a new scheme for quantum key distribution based on entanglement
swapping. By this protocol \QTR{em}{Alice} can securely share a random quantum
key with \QTR{em}{Bob}, without transporting any particle.Comment: Accepted by J. Opt. B: Quantum Semiclass. Op
Quantum Games and Quantum Strategies
We investigate the quantization of non-zero sum games. For the particular
case of the Prisoners' Dilemma we show that this game ceases to pose a dilemma
if quantum strategies are allowed for. We also construct a particular quantum
strategy which always gives reward if played against any classical strategy.Comment: 4 pages, 4 figures, typographic sign error in the definition of the
operator J correcte
Quantum key distribution via quantum encryption
A quantum key distribution protocol based on quantum encryption is presented
in this Brief Report. In this protocol, the previously shared
Einstein-Podolsky-Rosen pairs act as the quantum key to encode and decode the
classical cryptography key. The quantum key is reusable and the eavesdropper
cannot elicit any information from the particle Alice sends to Bob. The concept
of quantum encryption is also discussed.Comment: 4 Pages, No Figure. Final version to appear in PR
Quantum Nonlocality without Entanglement
We exhibit an orthogonal set of product states of two three-state particles
that nevertheless cannot be reliably distinguished by a pair of separated
observers ignorant of which of the states has been presented to them, even if
the observers are allowed any sequence of local operations and classical
communication between the separate observers. It is proved that there is a
finite gap between the mutual information obtainable by a joint measurement on
these states and a measurement in which only local actions are permitted. This
result implies the existence of separable superoperators that cannot be
implemented locally. A set of states are found involving three two-state
particles which also appear to be nonmeasurable locally. These and other
multipartite states are classified according to the entropy and entanglement
costs of preparing and measuring them by local operations.Comment: 27 pages, Latex, 6 ps figures. To be submitted to Phys. Rev. A.
Version 2: 30 pages, many small revisions and extensions, author added.
Version 3: Proof in Appendix D corrected, many small changes; final version
for Phys. Rev. A Version 4: Report of Popescu conjecture modifie
Theoretical efficient high capacity Quantum Key Distribution Scheme
A theoretical quantum key distribution scheme using EPR pairs is presented.
This scheme is efficient in that it uses all EPR pairs in distributing the key
except those chosen for checking eavesdroppers. The high capacity is achieved
because each EPR pair carries 2 bits of key code.Comment: 3 pages and 1 figure, to appear in Physical Review
Quantum Gambling Using Two Nonorthogonal States
We give a (remote) quantum gambling scheme that makes use of the fact that
quantum nonorthogonal states cannot be distinguished with certainty. In the
proposed scheme, two participants Alice and Bob can be regarded as playing a
game of making guesses on identities of quantum states that are in one of two
given nonorthogonal states: if Bob makes a correct (an incorrect) guess on the
identity of a quantum state that Alice has sent, he wins (loses). It is shown
that the proposed scheme is secure against the nonentanglement attack. It can
also be shown heuristically that the scheme is secure in the case of the
entanglement attack.Comment: no essential correction, 4 pages, RevTe
Efficient public-key cryptography with bounded leakage and tamper resilience
We revisit the question of constructing public-key encryption and signature schemes with security in the presence of bounded leakage and tampering memory attacks. For signatures we obtain the first construction in the standard model; for public-key encryption we obtain the first construction free of pairing (avoiding non-interactive zero-knowledge proofs). Our constructions are based on generic building blocks, and, as we show, also admit efficient instantiations under fairly standard number-theoretic assumptions.
The model of bounded tamper resistance was recently put forward by Damgård et al. (Asiacrypt 2013) as an attractive path to achieve security against arbitrary memory tampering attacks without making hardware assumptions (such as the existence of a protected self-destruct or key-update mechanism), the only restriction being on the number of allowed tampering attempts (which is a parameter of the scheme). This allows to circumvent known impossibility results for unrestricted tampering (Gennaro et al., TCC 2010), while still being able to capture realistic tampering attack
Role of causality in ensuring unconditional security of relativistic quantum cryptography
The problem of unconditional security of quantum cryptography (i.e. the
security which is guaranteed by the fundamental laws of nature rather than by
technical limitations) is one of the central points in quantum information
theory. We propose a relativistic quantum cryptosystem and prove its
unconditional security against any eavesdropping attempts. Relativistic
causality arguments allow to demonstrate the security of the system in a simple
way. Since the proposed protocol does not employ collective measurements and
quantum codes, the cryptosystem can be experimentally realized with the present
state-of-art in fiber optics technologies. The proposed cryptosystem employs
only the individual measurements and classical codes and, in addition, the key
distribution problem allows to postpone the choice of the state encoding scheme
until after the states are already received instead of choosing it before
sending the states into the communication channel (i.e. to employ a sort of
``antedate'' coding).Comment: 9 page
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