Observation of large CP violation in the neutral B meson system

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.     

Even-odd behavior of conductance in monatomic sodium wires

With the aid of the Friedel sum rule, we perform first-principles calculations of conductances through monatomic Na wires, taking into account the sharp tip geometry and discrete atomic structure of electrodes. We find that conductances (G) depend on the number (L) of atoms in the wires; G is G(0)( = 2e(2)/h) for odd L, independent of the wire geometry, while G is generally smaller than G(0) and sensitive to the wire structure for even L. This even-odd behavior is attributed to the charge neutrality and resonant character due to the sharp tip structure. We suggest that similar even-odd behavior may appear in other monovalent atomic wires.     

Calculation of transport parameters in KT-1 tokamak edge plasma

The radial profiles of KT-1 tokamak (major radius of 27 cm, minor radius of 4.25 cm, two poloidal stainless-steel limiters) edge plasma parameters are measured using single and triple electric probes. The particle transport parameters are calculated from the measured edge plasma parameters, and the results are analyzed by the simple fluid approximations. The cross-field particle diffusion coefficient (D) in the boundary plasma of the KT-1 is calculated from the density scrape-off length (λ_n) measured by using a triple probe. The particle density and electron temperature fall exponentially in the radial direction with the e-folding length of λ_n=0.13 cm and λ_e=0.41 cm, respectively. From the scrape-off layer (SOL) model, the experimental values of scrape-off length (λ_n) is used to calculate the cross-field diffusion coefficient (D=1.2×10³cm²/s), roughly corresponding to one third of the typical Bohm value. A simple SOL model with the contribution of recombination is introduced to evaluate the Bohm diffusion in the KT-1 tokamak edge plasma. Cross-field heat conductivity calculated from these deduced values is 5.2D in the SOL of KT-1 edge plasma. These results provide the finally certain information for edge particle transport in the KT-1 boundary plasmas.     

Betti numbers of modules of essentially monomial type

Let be a Noetherian local ring. In this paper we supply formulae for computing the ranks of syzygy and Betti numbers of -modules of essentially monomial type. These modules are defined with respect to various -regular sequences. For example, finite length modules of monomial type over regular local rings of dimension are modules of essentially monomial type with respect to -regular sequences of length . If a module is of essentially monomial type with respect to an -regular sequence of length , then the rank of its -th syzygy is at least and its -th Betti number is at least .

     

Cold acclimation improves recovery of cryopreserved grass (Zoysia and Lolium sp.)

Cold acclimation of Lolium L. and Zoysia Willd. Grass cultivars significantly increased regrowth of cryopreserved meristems. One wk of cold acclimation improved recovery following cryopreservation but extended acclimation (4-8 wk) resulted in the best regrowth. Cold acclimation also significantly increased the dehydration tolerance of both Zoysia and Lolium meristems. Lolium apices cold acclimated for 4 wk produced 60-100% regrowth following cryopreservation by slow freezing or encapsulation-dehydration. Cold-acclimated Zoysia had greater than 60% regrowth following encapsulation-dehydration when beads were dehydrated to less than 22% water content. Non-acclimated meristems of both genera had little or no regrowth. Thawed meristems grew quickly without callus formation and the plantlets produced were transplanted to pots in the greenhouse after 4 to 6 wk. Samples of each cultivar were stored in liquid nitrogen as part of the U.S. National Plant Germplasm System.     

Selective excitation of vibrational states by shaping of light-induced potentials

In this Letter we describe a method for population transfer using intense, ultrafast laser pulses. The selectivity is accomplished by careful shaping of light-induced potentials (LIPs). Creation and control of the LIPs is accomplished by choosing pairs of pulses with proper frequency detunings and time delays. As an example, selective population transfer is demonstrated for a three-state model of the sodium dimer.     

Universal torsion-induced interaction from large extra dimensions

We consider the Kaluza-Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fit to Z-pole observables, we find the 3sigma bound on the scale of quantum gravity to be 28 TeV for n = 2. If Dirac or light sterile neutrinos are present, the data from SN1987A increase the bound to sqrt[n] M(S)>/=210 TeV.     

电功率20 GW重复频率强流电子束二极管研究

采用静电场模拟对二极管结构及导引磁场位形分布进行了优化设计，并在20GW脉冲功率源上进行了重复频率运行实验研究，二极管输出电子束电压超过1MV，电流达20kA，脉冲宽度45ns，重复频率100Hz，达到了设计指标.     

A Comparative ESR Study on Blood and Tissue Nitric Oxide Concentration during Renal Ischemia-Reperfusion Injury

Electron paramagnetic resonance (EPR) spin trapping technology is a sensitive and unambiguous method for detection of nitric oxide (NO). Due to the short lifetime, NO must be trapped before EPR measurement. There are two EPR spin trapping techniques used currently, including the detections of EPR signals of diethyldithiocarbamate-iron-nitric oxide (DETC₂-Fe²⁺-NO) and nitrosyl hemoglobin (HbNO). In this study, we firstly investigated the kinetics of the EPR signal of DETC₂-Fe²⁺-NO in normal and ischemia-reperfused kidneys. In normal rat kidneys, the signal of DETC₂-Fe²⁺-NO was found at 5 min after the spin trappers Fe²⁺/DETC were administrated, the peak concentration was at 15 min and the period with relatively stable signal intensity was at the time range from 15 to 70 min. In the ischemia-reperfused rat kidneys, the signal of DETC₂-Fe²⁺-NO was increased at 30 min of ischemia and decreased at 60 min of ischemia after the occlusion of renal artery (corresponding to the time course of 60 and 90 min after Fe²⁺/DETC injection respectively). We then investigated the EPR signal of HbNO in blood. No characteristic HbNO signal was found in the rats of the sham control and 30 min of ischemia. An HbNO signal occurred in the rats exposed to 60 min of ischemia and it became pronounced with increased duration of reperfusion. The signal intensity reached a plateau at 150 min of reperfusion. The results suggest that the DETC₂-Fe²⁺-NO signal can be only suitable for the NO measurement in the short-term ischemia-reperfusion model, whereas the HbNO signal can be applied to represent NO in the relatively long-term ischemia-reperfusion model. In addition, N^G-nitro-L-arginine (L-NAME) and allopurinol were used to identify the source of NO. By detecting the HbNO signal, we demonstrated that the activation of xanthine oxidase is an important source of NO formation at the long-term period of ischemia and reperfusion. Authors' address: Jiangang Shen, School of Chinese Medicine, University of Hong Kong, 10 Sassoon Road, Hong Kong SAR, China