27,667 research outputs found
Signal processing in high speed OTDM networks
This paper presents the design and experimental results of an optical packet-switching testbed capable of performing message routing with single wavelength TDM packet bit rates as high as 100 Gb/s
Reduction of -Regular Noncrossing Partitions
In this paper, we present a reduction algorithm which transforms -regular
partitions of to -regular partitions of .
We show that this algorithm preserves the noncrossing property. This yields a
simple explanation of an identity due to Simion-Ullman and Klazar in connection
with enumeration problems on noncrossing partitions and RNA secondary
structures. For ordinary noncrossing partitions, the reduction algorithm leads
to a representation of noncrossing partitions in terms of independent arcs and
loops, as well as an identity of Simion and Ullman which expresses the Narayana
numbers in terms of the Catalan numbers
P53 tumour-suppressor gene mutations are mainly localised on exon 7 in human primary and metastatic prostate cancer.
Mutations in the p53 tumour-suppressor gene are among the most common genetic alterations in human cancers. In the present study we analysed the mutations in the p53 tumor-suppressor gene in 25 primary and 20 metastatic human prostate cancer specimens. DNA extracted from the paraffin-embedded sections was amplified by hot-start polymerase chain reaction, and p53 gene mutations in the conserved mid-region (exons 4-9) were examined using single-strand conformation polymorphism (SSCP) analysis and immunohistochemistry. In the present study, we used a novel hot-start PCR-SSCP technique using DNA Taq polymerase antibody, which eliminates primer-dimers and non-specific products. Because of this new technique, the results of PCR-SSCP showed very high resolution. Polymerase chain reaction products were sequenced directly for point mutations for the p53 gene. Mutations were found in 2 out of 25 primary prostate cancers (8%) and 4 out of 20 metastatic cancers (20%). Mutations were observed exclusively in exon 7 and not in exons 4, 5, 6, 8 or 9. Nuclear accumulation of p53 protein, determined by immunohistochemistry, correlated with the degree of metastasis in prostatic cancer
Riordan Paths and Derangements
Riordan paths are Motzkin paths without horizontal steps on the x-axis. We
establish a correspondence between Riordan paths and
-avoiding derangements. We also present a combinatorial proof
of a recurrence relation for the Riordan numbers in the spirit of the
Foata-Zeilberger proof of a recurrence relation on the Schr\"oder numbers.Comment: 9 pages, 2 figure
Heavy Pentaquarks
We construct the spin-flavor wave functions of the possible heavy pentaquarks
containing an anti-charm or anti-bottom quark using various clustered quark
models. Then we estimate the masses and magnetic moments of the or heavy pentaquarks. We emphasize the difference in the
predictions of these models. Future experimental searches at BESIII, CLEOc,
BELLE, and LEP may find these interesting states
The binary mass transfer origin of the red blue straggler sequence in M30
Two separated sequences of blue straggler stars (BSSs) have been revealed by
Ferraro et al. (2009) in the color-magnitude diagram (CMD) of the Milky Way
globular cluster M30. Their presence has been suggested to be related to the
two BSS formation channels (namely, collisions and mass-transfer in close
binaries) operating within the same stellar system. The blue sequence was
indeed found to be well reproduced by collisional BSS models. In contrast, no
specific models for mass transfer BSSs were available for an old stellar system
like M30. Here we present binary evolution models, including case-B mass
transfer and binary merging, specifically calculated for this cluster. We
discuss in detail the evolutionary track of a binary, which
spends approximately 4 Gyr in the BSS region of the CMD of a 13 Gyr old
cluster. We also run Monte-Carlo simulations to study the distribution of mass
transfer BSSs in the CMD and to compare it with the observational data. Our
results show that: (1) the color and magnitude distribution of synthetic mass
transfer BSSs defines a strip in the CMD that nicely matches the observed red
BSS sequence, thus providing strong support to the mass transfer origin for
these stars; (2) the CMD distribution of synthetic BSSs never attains the
observed location of the blue BSS sequence, thus reinforcing the hypothesis
that the latter formed through a different channel (likely collisions); (3)
most () of the synthetic BSSs are produced by mass-transfer models,
while the remaining requires the contribution from merger models.Comment: 8 pages, 5 figures, accepted to Ap
Nonlocality of Majorana modes in hybrid nanowires
Spatial separation of Majorana zero modes distinguishes trivial from topological midgap states and is key to topological protection in quantum computing applications. Although signatures of Majorana zero modes in tunneling spectroscopy have been reported in numerous studies, a quantitative measure of the degree of separation, or nonlocality, of the emergent zero modes has not been reported. Here, we present results of an experimental study of nonlocality of emergent zero modes in superconductor-semiconductor hybrid nanowire devices. The approach takes advantage of recent theory showing that nonlocality can be measured from splitting due to hybridization of the zero mode in resonance with a quantum dot state at one end of the nanowire. From these splittings as well as anticrossing of the dot states, measured for even and odd occupied quantum dot states, we extract both the degree of nonlocality of the emergent zero mode, as well as the spin canting angles of the nonlocal zero mode. Depending on the device measured, we obtain either a moderate degree of nonlocality, suggesting a partially separated Andreev subgap state, or a highly nonlocal state consistent with a well-developed Majorana modeThis research was supported by Microsoft, the Danish National Research Foundation, the European Commission, and the Spanish Ministry of Economy and Competitiveness through Grants No. FIS2015-65706-P, No. FIS2015-64654-P, and No. FIS2016-80434-P (AEI/FEDER, EU), the RamĂłn y Cajal programme Grant No. RYC-2011-09345, and the MarĂa de Maeztu Programme for Units of Excellence in R&D (Grant No. MDM-2014-0377). C.M.M. acknowledges support from the Villum Foundation. M.-T.D. acknowledges support from State Key Laboratory of High Performance Computing, Chin
Pentaquark Magnetic Moments In Different Models
We calculate the magnetic moments of the pentaquark states from different
models and compare our results with predictions of other groups.Comment: 17 pages, no figur
Magnetic Moments of Pentaquarks
If the of and pentaquarks is really found to
be by future experiments, they will be accompanied by
partners in some models. It is reasonable to expect that
these states will also be discovered in the near future with
the current intensive experimental and theoretical efforts. We estimate
pentaquark magnetic moments using different models.Comment: 13 page
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