5,703 research outputs found
Field test of a practical secure communication network with decoy-state quantum cryptography
We present a secure network communication system that operated with
decoy-state quantum cryptography in a real-world application scenario. The full
key exchange and application protocols were performed in real time among three
nodes, in which two adjacent nodes were connected by approximate 20 km of
commercial telecom optical fiber. The generated quantum keys were immediately
employed and demonstrated for communication applications, including unbreakable
real-time voice telephone between any two of the three communication nodes, or
a broadcast from one node to the other two nodes by using one-time pad
encryption.Comment: 10 pages, 2 figures, 2 tables, typos correcte
Distorted HI Gas in the Widely Separated LIRG Arp 256
We present new interferometric HI and CO (1-0) observations of the luminous
infrared source, Arp 256. Arp 256 consists of two spiral galaxies in an early
stage of merging, with a projected nuclear separation of 29 kpc (54") and an
infrared luminosity of 2.0E11 L_sun. Despite the large separation of the
galaxies' nuclei and mildly disrupted stellar components, the HI disks are
found to be strongly disrupted, and the southern galaxy in Arp 256 shows an
elevated star formation efficiency, which is consistent with a nuclear
starburst. Both of these results run contrary to expectations, posing
interesting questions on the physical mechanisms involved in stimulating star
formation during an interaction.Comment: 19 pages, 7 figures. Accepted for publication in AJ. Author added.
Full resolution figures available at
http://astro.uchicago.edu/home/web/jchen/arp25
Metropolitan all-pass and inter-city quantum communication network
We have demonstrated a metropolitan all-pass quantum communication network in
field fiber for four nodes. Any two nodes of them can be connected in the
network to perform quantum key distribution (QKD). An optical switching module
is presented that enables arbitrary 2-connectivity among output ports.
Integrated QKD terminals are worked out, which can operate either as a
transmitter, a receiver, or even both at the same time. Furthermore, an
additional link in another city of 60 km fiber (up to 130 km) is seamless
integrated into this network based on a trusted relay architecture. On all the
links, we have implemented protocol of decoy state scheme. All of necessary
electrical hardware, synchronization, feedback control, network software,
execution of QKD protocols are made by tailored designing, which allow a
completely automatical and stable running. Our system has been put into
operation in Hefei in August 2009, and publicly demonstrated during an
evaluation conference on quantum network organized by the Chinese Academy of
Sciences on August 29, 2009. Real-time voice telephone with one-time pad
encoding between any two of the five nodes (four all-pass nodes plus one
additional node through relay) is successfully established in the network
within 60km.Comment: 9 pages, 2 figures, 2 table
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Distinctive Genes Determine Different Intramuscular Fat and Muscle Fiber Ratios of the longissimus dorsi Muscles in Jinhua and Landrace Pigs
Meat quality is determined by properties such as carcass color, tenderness and drip loss. These properties are closely associated with meat composition, which includes the types of muscle fiber and content of intramuscular fat (IMF). Muscle fibers are the main contributors to meat mass, while IMF not only contributes to the sensory properties but also to the plethora of physical, chemical and technological properties of meat. However, little is known about the molecular mechanisms that determine meat composition in different pig breeds. In this report we show that Jinhua pigs, a Chinese breed, contains much higher levels of IMF than do Landrace pigs, a Danish breed. We analyzed global gene expression profiles in the longissimus dorsi muscles in Jinhua and Landrace breeds at the ages of 30, 90 and 150 days. Cross-comparison analysis revealed that genes that regulate fatty acid biosynthesis (e.g., fatty acid synthase and stearoyl-CoA desaturase) are expressed at higher levels in Jinhua pigs whereas those that regulate myogenesis (e.g., myogenic factor 6 and forkhead box O1) are expressed at higher levels in Landrace pigs. Among those genes which are highly expressed in Jinhua pigs at 90 days (d90), we identified a novel gene porcine FLJ36031 (pFLJ), which functions as a positive regulator of fat deposition in cultured intramuscular adipocytes. In summary, our data showed that the up-regulation of fatty acid biosynthesis regulatory genes such as pFLJ and myogenesis inhibitory genes such as myostatin in the longissimus dorsi muscles of Jinhua pigs could explain why this local breed produces meat with high levels of IMF
De-wetting of evaporating drops on regular patterns of triangular posts
Directional wicking and spreading of liquids can be achieved by regular micro-patterns of specifically designed topographic features that break
the reflection symmetry of the underlying pattern. The present study aims to understand the formation and stability of wetting films during
the evaporation of volatile liquid drops on surfaces with a micro-pattern of triangular posts arranged in a rectangular lattice. Depending
on the density and aspect ratio of the posts, we observe either spherical-cap shaped drops with a mobile three-phase contact line or the
formation of circular or angular drops with a pinned three-phase contact line. Drops of the latter class eventually evolve into a liquid film
extending to the initial footprint of the drop and a shrinking cap-shaped drop sitting on the film. The drop evolution is controlled by the
density and aspect ratio of the posts, while no influence of the orientation of the triangular posts on the contact line mobility becomes evident.
Our experiments corroborate previous results of systematic numerical energy minimization, predicting that conditions for a spontaneous
retraction of a wicking liquid film depend weakly on the orientation of the film edge relative to the micro-pattern
Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transition
We have performed low-temperature transport measurements on a disordered
two-dimensional electron system (2DES). Features of the strong localization
leading to the quantum Hall effect are observed after the 2DES undergoes a
direct insulator-quantum Hall transition with increasing the perpendicular
magnetic field. However, such a transition does not correspond to the onset of
strong localization. The temperature dependences of the Hall resistivity and
Hall conductivity reveal the importance of the electron-electron interaction
effects to the observed transition in our study.Comment: 9 pages, 4 figure
INFLUENCE OF APPROACH SPEED AND DISTANCE ON BIOMECHANICS DURING SINGLE-LEGGED RUNNING VERTICAL JUMP
The purpose of this study was to look into the kinematics, kinetics and EMG of the single legged running vertical jumps in different approach speed and distance. 12 basketball player performed single-legged running vertical jumps with 2 approach speed and 3 distance randomly. Kinematic and Kinetic data were collected by a force and 11 infrared high speed cameras. EMG data were recorded by Delsys surface EMG system. Two-way repeated measures AMOVA (2 speeds x 3 distance) was used for establishing differences (significance level p< .05). The jump height, jumt moment of lower extremity, knee power and the activation of tibialis anterior and gastrocnemius were found significantly larger in fast approach speed. We suggested using fast approach speed and 9m approach distance to enhance the single-legged running vertical jump ability
Diffusion entropy analysis on the scaling behavior of financial markets
In this paper the diffusion entropy technique is applied to investigate the
scaling behavior of financial markets. The scaling behaviors of four
representative stock markets, Dow Jones Industrial Average, Standard&Poor 500,
Heng Seng Index, and Shang Hai Stock Synthetic Index, are almost the same; with
the scale-invariance exponents all in the interval . These
results provide a strong evidence of the existence of long-rang correlation in
financial time series, thus several variance-based methods are restricted for
detecting the scale-invariance properties of financial markets. In addition, a
parsimonious percolation model for stock markets is proposed, of which the
scaling behavior agrees with the real-life markets well.Comment: 5 pages, 3 figure
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Multi-scale symbolic entropy analysis provides prognostic prediction in patients receiving extracorporeal life support
Introduction: Extracorporeal life support (ECLS) can temporarily support cardiopulmonary function, and is occasionally used in resuscitation. Multi-scale entropy (MSE) derived from heart rate variability (HRV) is a powerful tool in outcome prediction of patients with cardiovascular diseases. Multi-scale symbolic entropy analysis (MSsE), a new method derived from MSE, mitigates the effect of arrhythmia on analysis. The objective is to evaluate the prognostic value of MSsE in patients receiving ECLS. The primary outcome is death or urgent transplantation during the index admission. Methods: Fifty-seven patients receiving ECLS less than 24 hours and 23 control subjects were enrolled. Digital 24-hour Holter electrocardiograms were recorded and three MSsE parameters (slope 5, Area 6–20, Area 6–40) associated with the multiscale correlation and complexity of heart beat fluctuation were calculated. Results: Patients receiving ECLS had significantly lower value of slope 5, area 6 to 20, and area 6 to 40 than control subjects. During the follow-up period, 29 patients met primary outcome. Age, slope 5, Area 6 to 20, Area 6 to 40, acute physiology and chronic health evaluation II score, multiple organ dysfunction score (MODS), logistic organ dysfunction score (LODS), and myocardial infarction history were significantly associated with primary outcome. Slope 5 showed the greatest discriminatory power. In a net reclassification improvement model, slope 5 significantly improved the predictive power of LODS; Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in MODS. In an integrated discrimination improvement model, slope 5 added significantly to the prediction power of each clinical parameter. Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in sequential organ failure assessment. Conclusions: MSsE provides additional prognostic information in patients receiving ECLS. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0548-3) contains supplementary material, which is available to authorized users
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