Laser irradiated enhancement of the atomic electron capture rate in search of new physics

Electron capture processes are important for new physics searches and therefore a high capture rate is inevitably desired. We investigate a possibility of enhancement of an atomic electron capture rate by irradiating laser beam to "an atom". The possibility of the enhancement is shown as a consequence of an enhanced electron wave function at origin Psi(0) through an effectively increased mass of the electron. We find that order of magnitude enhancement can be achieved using the laser with intensity 10(10) W/mm(2), and energy of photon, of O (10(-3)) eV.Electronic version of an article published as International Journal of Modern Physics E, Vol: 16, Issue: 5(June 2007), 2007, P1349-P1360,DOI:10.1142/S021830130700671X (c)copyright World Scientific Publishing Company http://www.worldscinet.com/cgi-bin/details.cgi?id=pii:S0218301307006708&type=htmltextapplication/pdfjournal articl

Measurement of branching fraction and time-dependent CP asymmetry parameters in B^0 → D^*+D^*-K^{0}_{S}decays

We present a measurement of the branching fraction and time-dependent CP violation parameters for B^0 → D^*+D^*-K^{0}_{S} decays. These results are obtained from a 414 fb^{-1} data sample that contains 449×10^6 B\bar{B} pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We obtain the branching fraction, B(B^0→D^*+D*^-K^{O}_{S})= [3.4±0.4(stat)±0.7(syst)]×10^-3, which is in agreement with the current world average. We also obtain an upper limit on the product branching fraction for a possible two-body decay, B(B^0 → D_s1^+(2536)D^*-)B(D_s1^+(2536)→ D^*+K^{O}_{S})s^+, where s^±[equivalent]m2(D^*±K^{0}_{S}), we extract the CP violation parameters, J_c/J_0=0.60^{+0.25}_{-0.28}(stat)±0.08(syst), 2J_s1/J_0sin2φ_1=-0.17^{+0.42}_{-0.42}(stat)±0.09(syst), 2J_s2/J_0cos2φ_1=-0.23^{+0.43}_{-0.41}(stat)±0.13(syst). A large value of J_c/J_0 would indicate a significant resonant contribution from a broad unknown D_s^**+ state. Although the sign of the factor, 2J_s2/J_0, can be deduced from theory, no conclusion can be drawn regarding the sign of cos2φ_1 given the errors.journal articl

Inclusive Measurement of the Photon Energy Spectrum in b→sγ Decays

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Recurrent-neural-network-based error correction of tapping touchscreen in nonstationary vibrating environment

振動環境でタッチスクリーン入力を行うと，意図したキーと異なる入力が増えてしまう．このタップ位置のずれはタップ直前の振動と関係していると考えられる．本研究では走行中のバス車内でスマートフォン文字入力のタッピングデータを収集し，内蔵加速度センサから得られる加速度信号をもとに再帰型ニューラルネットワークを用いてタップ位置ずれを推定・補正する方法を検討した．その結果，14名分のユーザ依存モデルにより，タップ位置ずれの二乗平均平方根誤差がx軸，y軸方向でそれぞれ平均3.1%，8.4%削減されることを確認した．Tapping a touchscreen in a vibrating environment causes more errors than in a non-vibrating environment. We collected tapping data from participants using smartphones with triaxial acceleration signals while riding a local bus, typical nonstationary vibrating environments, and developed a recurrent-neural network-based positional-error correction model with an input of acceleration signals. The experimental results indicated that the proposed model reduced the root mean square error by 3.1% on the x-axis and 8.4% on the y-axis on average. However, the reduction rates were highly user-dependent.application/pdfdepartmental bulletin pape

Cellular Plasticity Enables Adaptation to Unforeseen Cell-Cycle Rewiring Challenges

<div><p>The fundamental dynamics of the cell cycle, underlying cell growth and reproduction, were previously found to be robust under a wide range of environmental and internal perturbations. This property was commonly attributed to its network structure, which enables the coordinated interactions among hundreds of proteins. Despite significant advances in deciphering the components and autonomous interactions of this network, understanding the interfaces of the cell cycle with other major cellular processes is still lacking. To gain insight into these interfaces, we used the process of genome-rewiring in yeast by placing an essential metabolic gene <em>HIS3</em> from the histidine biosynthesis pathway, under the exclusive regulation of different cell-cycle promoters. In a medium lacking histidine and under partial inhibition of the HIS3p, the rewired cells encountered an unforeseen multitasking challenge; the cell-cycle regulatory genes were required to regulate the essential histidine-pathway gene in concert with the other metabolic demands, while simultaneously driving the cell cycle through its proper temporal phases. We show here that chemostat cell populations with rewired cell-cycle promoters adapted within a short time to accommodate the inhibition of HIS3p and stabilized a new phenotypic state. Furthermore, a significant fraction of the population was able to adapt and grow into mature colonies on plates under such inhibiting conditions. The adapted state was shown to be stably inherited across generations. These adaptation dynamics were accompanied by a non-specific and irreproducible genome-wide transcriptional response. Adaptation of the cell-cycle attests to its multitasking capabilities and flexible interface with cellular metabolic processes and requirements. Similar adaptation features were found in our previous work when rewiring <em>HIS3</em> to the GAL system and switching cells from galactose to glucose. Thus, at the basis of cellular plasticity is the emergence of a yet-unknown general, non-specific mechanism allowing fast inherited adaptation to unforeseen challenges.</p> </div

The correlation of transcriptional response.

<p>A Pearson correlation coefficient was computed between all pairs of genes based on the array measurements presented in Fig. 4. The figure shows the distributions of correlation coefficient between all possible pairs for the experiment shown in Fig. 4a (pNdd1-<i>HIS3</i> strain, blue curve) and Fig. 4c (pSwi4-<i>HIS3</i> strain, red curve). The histograms are normalized to unit area and thus represent the probability density.</p

Rewiring the cell cycle network.

<p>(a) A schematic diagram of the cell cycle transcription regulation (based on ref <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045184#pone.0045184-Simon1" target="_blank">[15]</a> with modifications). Rewiring <i>HIS3</i> to be exclusively regulated by a duplicate of the cell cycle promoter regulating: (b) <i>Swi4</i>, (c) <i>Ndd1</i>, and (d) <i>Swi5</i>. Note that the native genes of the cell cycle network and their regulatory regions remained intact.</p

Growth exponents of the three strains in batch experiments.

<p>All clones were grown over more than 80 hours with or without histidine in the medium and with different concentrations of <i>3AT</i>. The OD measurements of the growing batch cultures were fitted with exponential functions e^t/τ.</p

Morphology of adapting cells.

<p>(a) For each of the three strains of Figs. 1b–d, a sample of cells was harvested from the chemostat at three time points: initial steady-state with no <i>3AT</i> (upper row), during the declining phase in cell density after the addition of 4 mM of <i>3AT</i> (middle row), and at the adapted steady state (lower row). Histograms of cell size distributions for the three phases (black-initial; red-declining transient phase; green-adapted state) for: (b) pSwi4-<i>HIS3</i> (number of cells analyzed: initial-1102, transient-330, adapted-1340 ) (c) pNdd1-<i>HIS3</i> (number of cells analyzed: initial-1454, transient −794, adapted −1426) and (d) pSwi5-<i>HIS3</i> (number of cells analyzed: initial-3950, transient-3165, adapted-3559). The histograms were normalized to unit area and thus represent the probability density.</p

Population growth dynamics of rewired strains.

<p>(a) The cell density as measured by the optical density in repetitive chemostat experiments with the three rewired strains: blue, pSwi4-<i>HIS3</i> (Fig. 1b), 3 experiments; red, pNdd1-<i>His3</i> (Fig. 1c), 3 experiments, and green pSwi5-<i>HIS3</i> (Fig. 1d), 2 experiments. The chemostats were stabilized at steady state in a medium lacking <i>3AT</i> and were switched to the same medium supplemented with 4 mM <i>3AT</i> at t = 0. Note the logarithmic y-axis. Bar-10 chemostat generations. Note the variability between repeated experiments. (b) The chemostat growth dynamics of “twin” populations of the strain pNdd1-<i>HIS3</i>, derived from a single steady-state mother population and decoupled prior to the switch into the challenging <i>3AT</i> medium. Switching to a medium with 4 mM <i>3AT</i> was done at t = 0. These chemostats are the same as two of the chemostats (red) shown in (a). (c) <b>Inherited adaptation</b>. A time-extended chemostat experiment with the strain pSwi4-<i>HIS3</i> showing that after the establishment of an adapted state in 4 mM <i>3AT</i>, removing the <i>3AT</i> from the medium almost did not have any effect on the population growth dynamics, while switching to 8 mM <i>3AT</i> caused a slight decline in the population density followed by re-adaptation to the new medium. The red curve depicts the concentration of <i>3AT</i>.</p