Quantum tunneling time

A simple model of a quantum clock is applied to the old and controversial problem of how long a particle takes to tunnel through a quantum barrier. The model I employ has the advantage of yielding sensible results for energy eigenstates, and does not require the use of time-dependant wave packets. Although the treatment does not forbid superluminal tunneling velocities, there is no implication of faster-than-light signaling because only the transit duration is measurable, not the absolute time of transit. A comparison is given with the weak-measurement post-selection calculations of Steinberg.Comment: 10 pages, no figures, research pape

Genetic diversity and selective breeding of red common carps in China

China has a very rich genetic diversity in common carp (Cyprinus carpio) and the red common carp plays an important role in Chinese aquaculture and genetic studies. Selective breeding, particularly crossbreeding has been applied successfully to red common carps in China, and the products of these efforts have been in commercial use since the 1970s. However, knowledge of the quantitative and molecular genetics of these carps is limited. Studies were therefore undertaken to: (1) understand the genetic diversity and genetic relationship of red common carps in China; (2) understand the inheritance of color phenotype of Oujiang color carp; (3) select stable Oujiang color carp with fast growth rate and ornamental Oujiang color carp comparable with the Koi common carp from Japan; (4) study the culture performance and culture systems suitable for the Oujiang color carp in cages and paddies; (5) extend better quality fish and appropriate culture systems for small scale fish farmers in poor areas

A Robust Rational Route to in a Simple Asset Pricing Model (revised March 2004)

We investigate asset pricing dynamics in an adaptive evolutionary asset pricing model with fundamentalists, trend followers and a market maker. Agents can choose between a fundamentalist strategy at positive information cost or choose a trend following strategy for free. Price adjustment is proportional to the excess demand in the asset market. Agents asynchronously update their strategy according to realized net profits in the recent past. As agents become more sensitive to differences in strategy performance, the fundamental steady state becomes unstable and multiple steady states may arise. As the traders' sensitivity to differences in fitness increases, a bifurcation route to chaos sets in due to homoclinic bifurcations of stable and unstable manifolds of the fundamental steady state.

Entanglement, quantum phase transition and scaling in XXZ chain

Motivated by recent development in quantum entanglement, we study relations among concurrence $C$, SU$_q$(2) algebra, quantum phase transition and correlation length at the zero temperature for the XXZ chain. We find that at the SU(2) point, the ground state possess the maximum concurrence. When the anisotropic parameter $\Delta$ is deformed, however, its value decreases. Its dependence on $\Delta$ scales as $C=C_0-C_1(\Delta-1)^2$ in the XY metallic phase and near the critical point (i.e. $1<\Delta<1.3$) of the Ising-like insulating phase. We also study the dependence of $C$ on the correlation length $\xi$, and show that it satisfies $C=C_0-1/2\xi$ near the critical point. For different size of the system, we show that there exists a universal scaling function of $C$ with respect to the correlation length $\xi$.Comment: 4 pages, 3 figures. to appear in Phys. Rev.

On Bures fidelity of displaced squeezed thermal states

Fidelity plays a key role in quantum information and communication theory. Fidelity can be interpreted as the probability that a decoded message possesses the same information content as the message prior to coding and transmission. In this paper, we give a formula of Bures fidelity for displaced squeezed thermal states directly by the displacement and squeezing parameters and birefly discuss how the results can apply to quantum information theory.Comment: 10 pages with RevTex require

2-(3-Hydroxy-propyl)isoindoline-1,3-dione:Competition among hydrogen-bond acceptors

The title compound, C11H11NO3, has two mol-ecules in the asymmetric unit, which differ in the orientation of their side-chain OH groups, allowing them to form inter-molecular O - H⋯O hydrogen bonds to different acceptors. In one case, the acceptor is the OH group of the other mol-ecule, and in the other case it is an imide O=C group. This is the first example in the N-substituted phthalimide series in which independent mol-ecules have different types of acceptor. Mol-ecular-orbital calculations place the greatest negative charge on the OH group. © 2008 International Union of Crystallography

Revisiting the Bs(∗)B^{(*)}_s-Meson Production at the Hadronic Colliders

The production of heavy-flavored hadron at the hadronic colliders provides a challenging opportunity to test the validity of pQCD predictions. There are two mechanisms for the $B^{(*)}_s$ hadroproduction, i.e. the gluon-gluon fusion mechanism via the subprocess $g+g\rightarrow B^{(*)}_s+b+\bar{s}$ and the extrinsic heavy quark mechanism via the subprocesses $g+\bar{b}\to B^{(*)}_s +\bar{s}$ and $g+s\to B^{(*)}_s +b$, both of which shall have sizable contributions in proper kinematic region. Different from the fixed-flavor-number scheme (FFNS) previously adopted in the literature, we study the $B^{(*)}_s$ hadroproduction under the general-mass variable-flavor-number scheme (GM-VFNS), in which we can consistently deal with the double counting problem from the above two mechanisms. Properties for the $B^{(*)}_s$ hadroproduction are discussed. To be useful reference, a comparative study of FFNS and GM-VFNS is presented. Both of which can provide reasonable estimations for the $B^{(*)}_s$ hadroproduction. At the Tevatron, the difference between these two schemes is small, however such difference is obvious at the LHC. The forthcoming more precise data on LHC shall provide a good chance to check which scheme is more appropriate to deal with the $B^{(*)}_s$-meson production and to further study the heavy quark components in hadrons.Comment: 18 pages, 8 figures, 4 tables. To match the published version. To be published in Eur.Phys.J.

Dynamics of heavy-Rydberg ion-pair formation in K(14p,20p)-SF6, CCl4ﾠcollisions

The dynamics of formation of heavy-Rydberg ion-pair states throughﾠelectron transferﾠin K(np)-SF6, CCl4ﾠcollisions is examined byﾠmeasuringﾠtheﾠvelocity,ﾠangular, and bindingﾠenergyﾠdistributions of the product ion pairs. The results areﾠanalyzedﾠwith the aid of a Monte Carlo collision code that models both the initial electron capture and the subsequent evolution of the ion pairs. The model simulations are in good agreement with the experimental data and highlight the factors such asﾠRydberg atomﾠsize, the kineticﾠenergyﾠof relativeﾠmotionﾠof theﾠRydberg atomﾠand target particle, and (in the case of attaching targets that dissociate) the energetics ofﾠdissociationﾠthat can be used to control the properties of the product ion-pair states

Role of CD8+ cells in the progression of murine adriamycin nephropathy

Role of CD8+ cells in the progression of murine adriamycin nephropathy.BackgroundMany studies have shown that interstitial inflammation in human and experimental renal disease is characterized by T-cell infiltration, but published data on the involvement of inflammatory cell subsets in progressive tubulointerstitial lesions are often conflicting. A previous study suggested a role for cytotoxic T lymphocytes in the damaging effect of CD4+ T-cell depletion in murine adriamycin (ADR) nephropathy, a model of focal segmental glomerulosclerosis (FSGS), and tubulointerstitial inflammation. The aim of this study was to investigate the role of CD8+ cells in this model.MethodsMale BALB/c mice were treated with five intraperitoneal injections of anti-CD8 monoclonal antibody (mAb), beginning from five days after ADR treatment, when overt proteinuria was established. Seven mice in each of groups A (ADR + mAb), B (ADR only), and C (saline treated, age matched) were sacrificed at week 6. Changes in renal function and histopathological features were assessed. Tubulointerstitial inflammation and glomerular inflammation were examined immunohistochemically.ResultsmAb treatment reduced CD8+ cell levels to <2% of normal in spleen. Proteinuria in group A was no different from that in group B at week 6, but was markedly higher than in group C. Creatinine clearance was significantly ameliorated by anti-CD8 treatment (71.8 ± 4.9 μL/min vs. 29.2 ± 2.8 in group B and 81.9 ± 3.7 in group C). Morphometric analysis showed less FSGS in group A compared with group B (6.5 ± 1.9 vs. 13.0 ± 2.8, P < 0.001), as well as less tubular atrophy (indicated by increased ratio of tubule cell height to tubular diameter, 0.25 ± 0.24 in group A vs. 0.04 ± 0.02 in group B, P < 0.05). CD8 depletion also reduced interstitial expansion (6.3 ± 2.2% vs. 16.4 ± 3.1 in group B, P < 0.001) and fibrosis (P < 0.01). Macrophage infiltration in tubulointerstitium was less in group A than in group B (P = 0.052). The number of interstitial CD4+ cells appeared to increase after anti-CD8 treatment, but was not statistically different between groups A and B.ConclusionAnti-CD8 treatment protects against renal functional and structural injury in this murine model of chronic proteinuric renal disease