27,601 research outputs found
Vulnerabilities in Quantum Key Distribution Protocols
Recently proposed quantum key distribution protocols are shown to be
vulnerable to a classic man-in-the-middle attack using entangled pairs created
by Eve. It appears that the attack could be applied to any protocol that relies
on manipulation and return of entangled qubits to create a shared key. The
protocols that are cryptanalyzed in this paper were proven secure with respect
to some eavesdropping approaches, and results reported here do not invalidate
these proofs. Rather, they suggest that quantum cryptographic protocols, like
conventional protocols, may be vulnerable to methods of attack that were not
envisaged by their designers.Comment: 6 pages, 1 figur
Understanding the truth about subjectivity
Results of two experiments show childrenās understanding of diversity in personal preference is incomplete. Despite acknowledging diversity, in Experiment 1(N=108), 6-
and 8-year-old children were less likely than adults to see preference as a legitimate basis for personal tastes and more likely to say a single truth could be found about a matter of taste. In Experiment 2 (N=96), 7- and 9-year-olds were less likely than 11- and 13-yearolds to say a dispute about a matter of preference might not be resolved. These data suggest that acceptance of the possibility of diversity does not indicate an adult-like understanding of subjectivity. An understanding of the relative emphasis placed on objective and subjective factors in different contexts continues to develop into adolescence
Quo vadimus? The 21st Century and multimedia
The concept is related of computer driven multimedia to the NASA Scientific and Technical Information Program (STIP). Multimedia is defined here as computer integration and output of text, animation, audio, video, and graphics. Multimedia is the stage of computer based information that allows access to experience. The concepts are also drawn in of hypermedia, intermedia, interactive multimedia, hypertext, imaging, cyberspace, and virtual reality. Examples of these technology developments are given for NASA, private industry, and academia. Examples of concurrent technology developments and implementations are given to show how these technologies, along with multimedia, have put us at the threshold of the 21st century. The STI Program sees multimedia as an opportunity for revolutionizing the way STI is managed
Quantum star-graph analogues of PT-symmetric square wells
We pick up a solvable symmetric quantum square well on an
interval of (with an dependent
non-Hermiticity given by Robin boundary conditions) and generalize it. In
essence, we just replace the support interval (reinterpreted
as an equilateral two-pointed star graph with the Kirchhoff matching at the
vertex ) by a pointed equilateral star graph
endowed with the simplest complex-rotation-symmetric external
dependent Robin boundary conditions. The remarkably compact form of
the secular determinant is then deduced. Its analysis reveals that (1) at any
integer , there exists the same, independent and infinite
subfamily of the real energies, and (2) at any special , there
exists another, additional and dependent infinite subfamily of the real
energies. In the spirit of the recently proposed dynamical construction of the
Hilbert space of a quantum system, the physical bound-state interpretation of
these eigenvalues is finally proposed.Comment: 20 pp, 1 figur
Labeling of Unique Sequences in Double-Stranded DNA at Sites of Vicinal Nicks Generated by Nicking Endonucleases
We describe a new approach for labeling of unique sequences within dsDNA under nondenaturing conditions. The method is based on the site-specific formation of vicinal nicks, which are created by nicking endonucleases (NEases) at specified DNA sites on the same strand within dsDNA. The oligomeric segment flanked by both nicks is then substituted, in a strand displacement reaction, by an oligonucleotide probe that becomes covalently attached to the target site upon subsequent ligation. Monitoring probe hybridization and ligation reactions by electrophoretic mobility retardation assay, we show that selected target sites can be quantitatively labeled with excellent sequence specificity. In these experiments, predominantly probes carrying a target-independent 3ā² terminal sequence were employed. At target labeling, thus a branched DNA structure known as 3ā²-flap DNA is obtained. The single-stranded terminus in 3ā²-flap DNA is then utilized to prime the replication of an externally supplied ssDNA circle in a rolling circle amplification (RCA) reaction. In model experiments with samples comprised of genomic Ī»-DNA and human herpes virus 6 type B (HHV-6B) DNA, we have used our labeling method in combination with surface RCA as reporter system to achieve both high sequence specificity of dsDNA targeting and high sensitivity of detection. The method can find applications in sensitive and specific detection of viral duplex DNA.Wallace A. Coulter Foundatio
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