6,261 research outputs found
Residue codes of extremal Type II Z_4-codes and the moonshine vertex operator algebra
In this paper, we study the residue codes of extremal Type II Z_4-codes of
length 24 and their relations to the famous moonshine vertex operator algebra.
The main result is a complete classification of all residue codes of extremal
Type II Z_4-codes of length 24. Some corresponding results associated to the
moonshine vertex operator algebra are also discussed.Comment: 21 pages, shortened from v
Experimental entanglement distillation of mesoscopic quantum states
The distribution of entangled states between distant parties in an optical
network is crucial for the successful implementation of various quantum
communication protocols such as quantum cryptography, teleportation and dense
coding [1-3]. However, owing to the unavoidable loss in any real optical
channel, the distribution of loss-intolerant entangled states is inevitably
inflicted by decoherence, which causes a degradation of the transmitted
entanglement. To combat the decoherence, entanglement distillation, which is
the process of extracting a small set of highly entangled states from a large
set of less entangled states, can be used [4-14]. Here we report on the
mesoscopic distillation of deterministically prepared entangled light pulses
that have undergone non-Gaussian noise. The entangled light pulses [15-17] are
sent through a lossy channel, where the transmission is varying in time
similarly to light propagation in the atmosphere. By employing linear optical
components and global classical communication, the entanglement is
probabilistically increased.Comment: 13 pages, 4 figures. It's the first submitted version to the Nature
Physics. The final version is already published on Nature Physics vol.4,
No.12, 919 - 923 (2008
Mass Transfer, Transiting Stream and Magnetopause in Close-in Exoplanetary Systems with Applications to WASP-12
We study mass transfer by Roche lobe overflow in close-in exoplanetary
systems. The planet's atmospheric gas passes through the inner Lagrangian point
and flows along a narrow stream, accelerating to 100-200\kms velocity before
forming an accretion disk. We show that the cylinder-shaped accretion stream
can have an area (projected in the plane of the sky) comparable to that of the
planet and a significant optical depth to spectral line absorption. Such a
"transiting cylinder" may produce an earlier ingress of the planet transit, as
suggested by recent HST observations of the WASP-12 system. The asymmetric disk
produced by the accretion stream may also lead to time-dependent obscuration of
the star light and apparent earlier ingress. We also consider the interaction
of the stellar wind with the planetary magnetosphere. Since the wind speed is
subsonic/sub-Alfvenic and comparable to the orbital velocity of the planet, the
head of the magnetopause lies eastward relative to the substellar line (the
line joining the planet and the star). The gas around the magnetopause may, if
sufficiently compressed, give rise to asymmetric ingress/egress during the
planet transit, although more works are needed to evaluate this possibility.Comment: 6 pages with 2 figures. Accepted in ApJ. Small changes (add
discussion on asymmetric disks
Assessing the Polarization of a Quantum Field from Stokes Fluctuation
We propose an operational degree of polarization in terms of the variance of
the projected Stokes vector minimized over all the directions of the Poincar\'e
sphere. We examine the properties of this degree and show that some problems
associated with the standard definition are avoided. The new degree of
polarization is experimentally determined using two examples: a bright squeezed
state and a quadrature squeezed vacuum.Comment: 4 pages, 2 figures. Comments welcome
Quantum reconstruction of an intense polarization squeezed optical state
We perform a reconstruction of the polarization sector of the density matrix
of an intense polarization squeezed beam starting from a complete set of Stokes
measurements. By using an appropriate quasidistribution, we map this onto the
Poincare space providing a full quantum mechanical characterization of the
measured polarization state.Comment: 4 pages, 4 eps color figure
Effects of Neurotrophin-3 Plasmids on Myocyte Apoptosis and Ca²⁺-ATPase Content in the Muscle After Nerve Injury in Rats
We estimated the influence of plasmids with DNA carrying the neurotrophin-3 (NT-3) gene
on apoptosis in the gastrocnemius muscle and content of Ca²⁺-ATPase in the latter after
sciatic nerve injury. Sixty adult Wistar rats were randomly divided into the saline (control)
and NT-3 groups. The related indices, such as expression of caspase-3 protein, the rate of
apoptosis in the muscle evaluated using a TUNEL technique, and the level of Ca²⁺-ATPase
estimated using Western blot, were observed. Expression of caspase-3 protein was elevated
at different post-operative times after peripheral nerve injury; NT-3 expression and the rate
of muscle cell apoptosis decreased, whereas the level of Ca²⁺-ATPase in the sarcoplasmic
reticulum increased; significant differences were observed compared with the saline group (P
< 0.05). The mitigation mechanism of NT-3 on muscle atrophy after peripheral nerve injury is
expressed as inhibition of caspase-3 gene expression, increase in the Ca²⁺-ATPase level, and
reduction in the rate of muscle apoptosis.Ми вивчали вплив плазмід із ДНК, що несе ген нейротрофіну-3 (NT-3), на апоптоз міоцитів у m. gastrocnemius та вміст
Ca²⁺-ATФази в цьому м’язі після перерізання сідничного
нерва. 60 дорослих щурів лінії Вістар були рандомізовано
поділені на контрольну (введення фізіологічного розчину)
та NT-3-групи. Оцінювали відповідні показники – експресію протеїну каспази-3, рівень апоптозу в м’язі (з використанням TUNEL-методики) та рівень Ca²⁺-ATФази (з використанням Вестерн-блотингу). Експресія білка каспази-3 в
різні часові інтервали після пошкодження периферичного
нерва була підвищеною; експресія NT-3 та рівень апоптозу
м’язових клітин були знижені, а вміст Ca²⁺-ATФази в саркоплазматичному ретикулумі – підвищеним. Відмінності цих
показників щодо таких у контрольній групі були вірогідними (P < 0.05). Обмежуючі впливи NT-3 на процес м’язової
атрофії після пошкодження периферичного нерва виявлялись як інгібування експресії гена каспази-3, підвищення
вмісту Ca²⁺-ATФази та зниження інтенсивності апоптозу в
м’язі
Noiseless Linear Amplification and Distillation of Entanglement
The idea of signal amplification is ubiquitous in the control of physical
systems, and the ultimate performance limit of amplifiers is set by quantum
physics. Increasing the amplitude of an unknown quantum optical field, or more
generally any harmonic oscillator state, must introduce noise. This linear
amplification noise prevents the perfect copying of the quantum state, enforces
quantum limits on communications and metrology, and is the physical mechanism
that prevents the increase of entanglement via local operations. It is known
that non-deterministic versions of ideal cloning and local entanglement
increase (distillation) are allowed, suggesting the possibility of
non-deterministic noiseless linear amplification. Here we introduce, and
experimentally demonstrate, such a noiseless linear amplifier for
continuous-variables states of the optical field, and use it to demonstrate
entanglement distillation of field-mode entanglement. This simple but powerful
circuit can form the basis of practical devices for enhancing quantum
technologies. The idea of noiseless amplification unifies approaches to cloning
and distillation, and will find applications in quantum metrology and
communications.Comment: Submitted 10 June 200
Imbalanced functional link between executive control network and reward network explain the online-game seeking behaviors in Internet gaming disorder
Literatures have shown that Internet gaming disorder (IGD) subjects show impaired executive control and enhanced reward sensitivities than healthy controls. However, how these two networks jointly affect the valuation process and drive IGD subjects' online-game-seeking behaviors remains unknown. Thirty-five IGD and 36 healthy controls underwent a resting-states scan in the MRI scanner. Functional connectivity (FC) was examined within control and reward network seeds regions, respectively. Nucleus accumbens (NAcc) was selected as the node to find the interactions between these two networks. IGD subjects show decreased FC in the executive control network and increased FC in the reward network when comparing with the healthy controls. When examining the correlations between the NAcc and the executive control/reward networks, the link between the NAcc - executive control network is negatively related with the link between NAcc - reward network. The changes (decrease/increase) in IGD subjects' brain synchrony in control/reward networks suggest the inefficient/overly processing within neural circuitry underlying these processes. The inverse proportion between control network and reward network in IGD suggest that impairments in executive control lead to inefficient inhibition of enhanced cravings to excessive online game playing. This might shed light on the mechanistic understanding of IGD
Rising to the occasion : disaster social work in China
Author name used in this manuscript: Timothy SIM2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
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