3,927 research outputs found
Hardy's Paradox for High-Dimensional Systems: Beyond Hardy's Limit
Hardy's proof is considered the simplest proof of nonlocality. Here we
introduce an equally simple proof that (i) has Hardy's as a particular case,
(ii) shows that the probability of nonlocal events grows with the dimension of
the local systems, and (iii) is always equivalent to the violation of a tight
Bell inequality.Comment: REVTeX4, 5 pages, 1 figure. Typo in Eq. (17) corrected. Ref. [5]
complete
Hair cell maturation is differentially regulated along the tonotopic axis of the mammalian cochlea
Sound amplification within the mammalian cochlea depends upon specialized hair cells, the outer hair cells (OHCs), which possess both sensory and motile capabilities. In various altricial rodents, OHCs become functionally competent from around postnatal day 7 (P7), before the primary sensory inner hair cells (IHCs), which become competent at about the onset of hearing (P12). The mechanisms responsible for the maturation of OHCs and their synaptic specialization remain poorly understood. We report that spontaneous Ca2+ activity in the immature cochlea, which is generated by CaV1.3 Ca2+ channels, differentially regulates the maturation of hair cells along the cochlea. Under near‐physiological recording conditions we found that, similar to IHCs, immature OHCs elicited spontaneous Ca2+ action potentials (APs), but only during the first few postnatal days. Genetic ablation of these APs in vivo, using CaV1.3−/− mice, prevented the normal developmental acquisition of mature‐like basolateral membrane currents in low‐frequency (apical) hair cells, such as IK,n (carried by KCNQ4 channels), ISK2 and IACh (α9α10nAChRs) in OHCs and IK,n and IK,f (BK channels) in IHCs. Electromotility and prestin expression in OHCs were normal in CaV1.3−/− mice. The maturation of high‐frequency (basal) hair cells was also affected in CaV1.3−/− mice, but to a much lesser extent than apical cells. However, a characteristic feature in CaV1.3−/− mice was the reduced hair cell size irrespective of their cochlear location. We conclude that the development of low‐ and high‐frequency hair cells is differentially regulated during development, with apical cells being more strongly dependent on experience‐independent Ca2+ APs
Beyond Gisin's Theorem and its Applications: Violation of Local Realism by Two-Party Einstein-Podolsky-Rosen Steering
We demonstrate here that for a given mixed multi-qubit state if there are at
least two observers for whom mutual Einstein-Podolsky-Rosen steering is
possible, i.e. each observer is able to steer the other qubits into two
different pure states by spontaneous collapses due to von Neumann type
measurements on his/her qubit, then nonexistence of local realistic models is
fully equivalent to quantum entanglement (this is not so without this
condition). This result leads to an enhanced version of Gisin's theorem
(originally: all pure entangled states violate local realism). Local realism is
violated by all mixed states with the above steering property. The new class of
states allows one e.g. to perform three party secret sharing with just pairs of
entangled qubits, instead of three qubit entanglements (which are currently
available with low fidelity). This significantly increases the feasibility of
having high performance versions of such protocols. Finally, we discuss some
possible applications.Comment: 9 pages, 1 figur
Beating the Clauser-Horne-Shimony-Holt and the Svetlichny games with Optimal States
We study the relation between the maximal violation of Svetlichny's
inequality and the mixedness of quantum states and obtain the optimal state
(i.e., maximally nonlocal mixed states, or MNMS, for each value of linear
entropy) to beat the Clauser-Horne-Shimony-Holt and the Svetlichny games. For
the two-qubit and three-qubit MNMS, we showed that these states are also the
most tolerant state against white noise, and thus serve as valuable quantum
resources for such games. In particular, the quantum prediction of the MNMS
decreases as the linear entropy increases, and then ceases to be nonlocal when
the linear entropy reaches the critical points and for the
two- and three-qubit cases, respectively. The MNMS are related to classical
errors in experimental preparation of maximally entangled states.Comment: 7 pages, 3 figures; minor changes; accepted in Physical Review
Quantum contextuality for a relativistic spin-1/2 particle
The quantum predictions for a single nonrelativistic spin-1/2 particle can be
reproduced by noncontextual hidden variables. Here we show that quantum
contextuality for a relativistic electron moving in a Coulomb potential
naturally emerges if relativistic effects are taken into account. The
contextuality can be identified through the violation of noncontextuality
inequalities. We also discuss quantum contextuality for the free Dirac electron
as well as the relativistic Dirac oscillator.Comment: REVTeX4, 5 page
Dirac Equation at Finite Temperature
In this paper, we propose finite temperature Dirac equation, which can
describe the quantum systems in an arbitrary temperature for a relativistic
particle of spin-1/2. When the temperature T=0, it become Dirac equation. With
the equation, we can study the relativistic quantum systems in an arbitrary
temperature.Comment: arXiv admin note: text overlap with arXiv:1005.2751,
arXiv:hep-ph/0004125, arXiv:hep-ph/0005272 by other author
VEGF attenuates development from cardiac hypertrophy to heart failure after aortic stenosis through mitochondrial mediated apoptosis and cardiomyocyte proliferation
<p>Abstract</p> <p>Background</p> <p>Aortic stenosis (AS) affects 3 percent of persons older than 65 years and leads to greater morbidity and mortality than other cardiac valve diseases. Surgery with aortic valve replacement (AVR) for severe symptomatic AS is currently the only treatment option. Unfortunately, in patients with poor ventricular function, the mortality and long-term outcome is unsatisfied, and only a minority of these patients could bear surgery. Our previous studies demonstrated that vascular endothelial growth factor (VEGF) protects cardiac function in myocardial infarction model through classic VEGF-PI3k-Akt and unclear mitochondrial anti-apoptosis pathways; promoting cardiomyocyte (CM) proliferation as well. The present study was designed to test whether pre-operative treatment with VEGF improves AS-induced cardiac dysfunction, to be better suitable for AVR, and its potential mechanism.</p> <p>Methods</p> <p>Adult male mice were subjected to AS or sham operation. Two weeks later, adenoviral VEGF (Ad-VEGF), enhanced green fluorescence protein (Ad-EGFP, as a parallel control) or saline was injected into left ventricle free wall. Two weeks after delivery, all mice were measured by echocardiography and harvested for further detection.</p> <p>Results</p> <p>AS for four weeks caused cardiac hypertrophy and left ventricular dysfunction. VEGF treatment increased capillary density, protected mitochondrial function, reduced CMs apoptosis, promoted CMs proliferation and eventually preserved cardiac function.</p> <p>Conclusions</p> <p>Our findings indicate that VEGF could repair AS-induced transition from compensatory cardiac hypertrophy to heart failure.</p
Analysis of drug resistance determinants in Klebsiella pneumoniae isolates from a tertiary-care hospital in Beijing, China.
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