Manipulating decay rates by entanglement and the Zeno effect

We analyse a class of quantum dynamical processes which may lead to the hindering of the decay of a non-stationary state through appropriate entanglement with an additional two-level system. In this case the process can be considered as a module whose iteration is related to dynamical implementations of the so called quantum Zeno effect.Comment: 7 pages, no figure

MC decomposition and boride formation in a next generation polycrystalline Ni based superalloy during isothermal exposure at 900 °C

Detailed microstructural characterisation of phases present in a next generation polycrystalline Ni based superalloy after thermal exposure at 900 °C was carried out, focusing on carbides and borides. Metastable M5B3 precipitated after 32 h had a stoichiometry of (Cr0.7Mo0.2W0.1)5B3 with substitutions with Ni, Co, Nb and Ta. Fine M23C6 (a = 10.62 Å) was overgrown by metastable M5B3, as shown by rigorous TEM-SAD pattern investigation. The borides were eventually dominated by Mo rich M3B2, at the apparent expense of MC. Decomposition of MC was confirmed; it transformed sequentially to γ and then γ΄. The primary driving force for the MC decomposition was attributed to γ΄ precipitation, increasing its fraction to the thermodynamic equilibrium at 900 °C

Semiclassical Dynamics from Zeno-Like measurements

The usual semiclassical approximation for atom-field dynamics consists in substituting the field operators by complex numbers related to the (supposedly large enough) intensity of the field. We show that a semiclassical evolution for coupled systems can always be obtained by frequent Zeno-like measurements on the state of one subsystems, independently of the field intensity in the example given. We study the Jaynes Cummings model from this perspective

How to encourage customers to use legal software

This study attempts to identify customer retention strategies for legal software and discusses their effectiveness for three consumer groups (stayers, dissatisfied switchers, and satisfied switchers). Although previous studies propose several antipirating strategies, they do not discuss how to enhance customer intentions to use legal software, which is crucial for software companies. The authors provide four generic retention strategies developed from both antipiracy and customer loyalty literature. The results indicate lower-pricing, legal, communication, and product strategies all enhance customer purchase intentions toward legal software. The lower-pricing strategy is more useful for stayers and dissatisfied switchers, and the communication strategy is most useful for dissatisfied switchers. Both the legal and product strategies have similar impacts on purchase intentions across the three segments. From a firm perspective, a product strategy is most worthwhile and useful across all segments

The contents and forms of solid-phase species of radioactive strontium and cesium in Taiwan soils

This study was to investigate the activities and contents of Cs-137 in the profiles of selected arable and forest soils in Taiwan and various solid-phase species of Sr-85 and Cs-137 in selected arable soils in Taiwan. The gamma (gamma) ray spectra of the collected soil samples and some of the soils amended with Sr-85 and Cs-137 were measured. The data indicate that the arable soils from Sanhsing series, Sanhsing Township and Chuangwei series, Chuangwei Township, Ilan County, and from Tunglochuan series, Pinglin Township, Taipei County shows significantly higher radioactivity of Cs-137 ( ND - 11.0 +/- 0.2 Bq kg(-1)). Furthermore, the radioactivity of Cs-137 in the mountain soils ( 1.24 +/- 0.07 - 42 +/- 1 Bq kg(-1)) from Yuanyang Lake Nature Preserve among Ilan, Taoyuan, and Hsinchu Counties is the highest among the investigated mountain forest soils. This may be mainly attributed to the fact that Ilan County is located in the northeastern part of Taiwan and faces the northeastern and northern seasonal winds with lots of precipitation annually from mid-autumn through mid-spring next year and is receiving greater amount of fallouts yearly. Due to longer reaction period (> 3 y) of Cs-137 with soil components, Cs-137 was mainly in the forms bound to oxides and to organic matter in the soil amended with Cs-137 and in the soil contaminated with Cs-137. On the contrary, due to shorter reaction period (< 60 d) of Sr-85 with soil components, Sr-85 was mainly in exchangeable form and partially in the forms bound to carbonates and oxides in the soils amended with Sr-85

Comment on "Evolution of a Quasi-Stationary State"

Approximately forty years ago it was realized that the time development of decaying systems might not be precisely exponential. Rolf Winter (Phys. Rev. {\bf 123}, 1503 (1961)) analyzed the simplest nontrivial system - a particle tunneling out of a well formed by a wall and a delta-function. He calculated the probability current just outside the well and found irregular oscillations on a short time scale followed by an exponential decrease followed by more oscillations and finally by a decrease as a power of the time. We have reanalyzed this system, concentrating on the survival probability of the particle in the well rather than the probability current, and find a different short time behavior.Comment: 8 pages, 6 figures, RevTex

Gravitational anomalies signaling the breakdown of classical gravity

Recent observations for three types of astrophysical systems severely challenge the GR plus dark matter scenario, showing a phenomenology which is what modified gravity theories predict. Stellar kinematics in the outskirts of globular clusters show the appearance of MOND type dynamics on crossing the $a_{0}$ threshold. Analysis shows a ``Tully-Fisher'' relation in these systems, a scaling of dispersion velocities with the fourth root of their masses. Secondly, an anomaly has been found at the unexpected scales of wide binaries in the solar neighbourhood. Binary orbital velocities cease to fall along Keplerian expectations, and settle at a constant value, exactly on crossing the $a_{0}$ threshold. Finally, the inferred infall velocity of the bullet cluster is inconsistent with the standard cosmological scenario, where much smaller limit encounter velocities appear. This stems from the escape velocity limit present in standard gravity; the ``bullet'' should not hit the ``target'' at more than the escape velocity of the joint system, as it very clearly did. These results are consistent with extended gravity, but would require rather contrived explanations under GR, each. Thus, observations now put us in a situation where modifications to gravity at low acceleration scales cease to be a matter of choice, to now become inevitable.Comment: 10 pages, 5 figures, Astrophysics and Space Science Proceedings 38, 4

A reduction of unilateral ureteral obstruction-induced renal fibrosis by a therapy combining valsartan with aliskiren

Wu WP, Chang CH, Chiu YT, Ku CL, Wen MC, Shu KH, Wu MJ. A reduction of unilateral ureteral obstruction-induced renal fibrosis by a therapy combining valsartan with aliskiren. Am J Physiol Renal Physiol 299: F929-F941, 2010. First published August 4, 2010; doi:10.1152/ajprenal.00192.2010.-The protective effect of combination therapy with valsartan and aliskiren against renal fibrosis remains to be defined. This study was undertaken to examine the protective effects of the combination of valsartan and aliskiren against renal fibrosis induced by unilateral ureteral obstruction (UUO). Combination therapy with valsartan (15 mg . kg(-1) . day(-1)) and aliskiren (10 mg . kg(-1) . day(-1)), valsartan monotherapy (30 mg . kg(-1) . day(-1)), and aliskiren monotherapy (20 mg . kg(-1) . day(-1)) all significantly ameliorated the increase in blood urea nitrogen and the degree of hydronephrosis determined by the increase in weight and length of the obstructed kidney. The dose titration study and blood pressure measurement confirmed that the combination therapy provided a greater benefit independent of the vasodilatory effect. There were no significant changes in serum levels of creatinine, sodium, and potassium in UUO rats and any treatment groups. Combination therapy also attenuated UUO-related increases in the scores of tubular dilatation, interstitial volume, interstitial collagen deposition, alpha-smooth muscle actin, the activation of ERK 1/2, the infiltration of monocytes/macrophages, the mRNA expression of snail-1, and transforming growth factor-beta 1 to a greater extent compared with aliskiren or valsartan used alone. The mRNA expression of renin and the (pro) renin receptor significantly increased after UUO. Combination therapy and monotherapy of valsartan and aliskiren had a comparable enhancing effect on the mRNA expression of renin, whereas all these treatments did not affect the expression of the (pro) renin receptor. In conclusion, a direct renin inhibitor in conjunction with an angiotensin II receptor blocker exerts increased renal protection against renal fibrosis and inflammation during obstruction over either agent alone

Wide binaries as a critical test of Classical Gravity

Modified gravity scenarios where a change of regime appears at acceleration scales $a<a_{0}$ have been proposed. Since for $1 M_{\odot}$ systems the acceleration drops below $a_{0}$ at scales of around 7000 AU, a statistical survey of wide binaries with relative velocities and separations reaching $10^{4}$ AU and beyond should prove useful to the above debate. We apply the proposed test to the best currently available data. Results show a constant upper limit to the relative velocities in wide binaries which is independent of separation for over three orders of magnitude, in analogy with galactic flat rotation curves in the same $a<a_{0}$ acceleration regime. Our results are suggestive of a breakdown of Kepler's third law beyond $a \approx a_{0}$ scales, in accordance with generic predictions of modified gravity theories designed not to require any dark matter at galactic scales and beyond.Comment: accepted for publication in EPJ

Cosmic histories of star formation and reionization: An analysis with a power-law approximation

With a simple power-law approximation of high-redshift ($\gtrsim3.5$) star formation history, i.e., $\dot{\rho}_*(z)\propto [(1+z)/4.5]^{-\alpha}$, we investigate the reionization of intergalactic medium (IGM) and the consequent Thomson scattering optical depth for cosmic microwave background (CMB) photons. A constraint on the evolution index $\alpha$ is derived from the CMB optical depth measured by the {\it Wilkinson Microwave Anisotropy Probe} (WMAP) experiment, which reads $\alpha\approx2.18\lg{\mathscr{N}_{\gamma}}-3.89$, where the free parameter $\mathscr{N}_\gamma$ is the number of the escaped ionizing ultraviolet photons per baryon. Moreover, the redshift for full reionization, $z_f$, can also be expressed as a function of $\alpha$ as well as $\mathscr{N}_{\gamma}$. By further taking into account the implication of the Gunn-Peterson trough observations to quasars for the full reionization redshift, i.e., $6\lesssim z_f \lesssim7$, we obtain $0.3\lesssim\alpha\lesssim1.3$ and $80\lesssim\mathscr{N}_{\gamma}\lesssim230$. For a typical number of $\sim4000$ of ionizing photons released per baryon of normal stars, the fraction of these photons escaping from the stars, $f_{\rm esc}$, can be constrained to within the range of $(2.0-5.8)$.Comment: 10 pages, 4 figures, accepted for publication in JCA