Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

Hyperfine structure and nuclear hyperpolarization observed in the bound exciton luminescence of Bi donors in natural Si

As the deepest group-V donor in Si, Bi has by far the largest hyperfine interaction and also a large I = 9/2 nuclear spin. At zero field this splits the donor ground state into states having total spin 5 and 4, which are fully resolved in the photoluminescence spectrum of Bi donor bound excitons. Under a magnetic field, the 60 expected allowed transitions cannot be individually resolved, but the effects of the nuclear spin distribution, -9/2 < or = I(z) < or = 9/2, are clearly observed. A strong hyperpolarization of the nuclear spin towards I(z) = -9/2 is observed to result from the nonresonant optical excitation. This is very similar to the recently reported optical hyperpolarization of P donors observed by EPR at higher magnetic fields. We introduce a new model to explain this effect, and predict that it may be very fast.

Simultaneous subsecond hyperpolarization of the nuclear and electron spins of phosphorus in silicon by optical pumping of exciton transitions

We demonstrate a method which can hyperpolarize both the electron and nuclear spins of 31P donors in Si at low field, where both would be essentially unpolarized in equilibrium. It is based on the selective ionization of donors in a specific hyperfine state by optically pumping donor bound exciton hyperfine transitions, which can be spectrally resolved in 28Si. Electron and nuclear polarizations of 90% and 76%, respectively, are obtained in less than a second, providing an initialization mechanism for qubits based on these spins, and enabling further ESR and NMR studies on dilute 31P in 28Si.

Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector

We have searched for proton decays via p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;{33} and 6.6 x 10;{33} years at 90% confidence level for p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} modes, respectively.

New measurement of the K+-->pi+ nunu branching ratio

Three events for the decay K+-->pi+ nunu have been observed in the pion momentum region below the K+-->pi+pi0 peak, 140 < Ppi < 199 MeV/c, with an estimated background of 0.93+/-0.17(stat.) -0.24+0.32(syst.) events. Combining this observation with previously reported results yields a branching ratio of B(K+-->pi+ nunu) = (1.73(-1.05)+1.15) x 10(-10) consistent with the standard model prediction.

Advanced semiconductor diagnosis by multidimensional electron-beam-induced current technique

We present advanced semiconductor diagnosis by using electron-beam-induced current (EBIC) technique. By varying the parameters such as temperature, accelerating voltage (V(acc)), bias voltage, and stressing time, it is possible to extend EBIC application from conventional defect characterization to advanced device diagnosis. As an electron beam can excite a certain volume even beneath the surface passive layer, EBIC can be effectively employed to diagnose complicated devices with hybrid structure. Three topics were selected to demonstrate EBIC applications. First, the recombination activities of grain boundaries and their interaction with Fe impurity in photovoltaic multicrystalline Si (mc-Si) are clarified by temperature-dependent EBIC. Second, the detection of dislocations between strained-Si and SiGe virtual substrate are shown to overcome the limitation of depletion region. Third, the observation of leakage sites in high-k gate dielectric is demonstrated for the characterization of advanced hybrid device structures.

Neuropeptides and their receptors of the protochordate, Ciona intestinalis: the evolutionary origin of vertebrate neuropeptides

Ci-TK and Ci-TK-R are authentic tachykinin (TK) and TK receptor isolated from a protochordate, Ciona intestinalis. In this study, we investigated a novel function of TK as an enhancer of oocyte growth. Ci-TK-R is expressed specifically in the Ciona vitellogenic oocytes. Moreover, administration of Ci-TK to the Ciona ovary resulted in upregulation of gene expression and enzymatic activity of several proteases. Moreover, maturation of the Ciona oocytes from the vitellogenic stage to the post-vitellogenic stage was induced in the presence of Ci-TK, which was completely blocked by addition of protease inhibitors.

Novel mutations in a Japanese patient with CD19 deficiency

Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by recurrent bacterial infections, hypogammaglobulinemia and low to normal numbers of circulating B cells. Mutations in the ICOS, TACI and CD19 genes have recently been identified in <10% of CVID patients. We, herein, describe two novel CD19 gene disruptions in an 8-year-old Japanese boy, who had been clinically diagnosed as having CVID at the age of 5 years. Flow-cytometric analysis demonstrated absence of CD19 and reduced CD21 expression on CD20-postive peripheral blood B cells. Mutation analysis of CD19 revealed a mutation in the splice acceptor site of intron 5 (IVS5-1G>T) of the maternal allele, resulting in skipping of exon 6, and a truncated protein product. The paternal allele was disrupted by a gross deletion encompassing at least the ATP2A1, CD19 and NFATC2IP genes. The patient had a small number of IgD(-) CD27(+) memory B cells, in which somatic mutation were detected. His B cells showed substantial proliferation upon stimulation, but reduced IgG and IgA production in vitro. These findings extend the mutation spectrum of the CD19 deficiency to four, and confirm the homogeneity of the CD19 deficiency as a unique type of CVID.

Point mutations in helper component protease of clover yellow vein virus are associated with the attenuation of RNA-silencing suppression activity and symptom expression in broad bean

Helper component protease (HC-Pro) is a potyvirus-encoded multifunctional protein and a major determinant of symptom expression in a susceptible plant. Here, we show the involvement of clover yellow vein virus (ClYVV) HC-Pro in necrotic symptom expression in broad bean (Vicia faba cv. Wase). In this host, lethal necrosis was induced by ClYVV no. 30, from which a spontaneous, mosaic-inducing mutant (MM) was obtained. Mapping with chimeric viruses between ClYVV no. 30 and MM attributed the symptom attenuation to two mutations at the HC-Pro positions 27 (threonine to isoleucine) and 193 (aspartic acid to tyrosine). Although neither mutant with the single amino acid substitution at position 27 or 193 (ClYVV/T27I or D193Y) induced the lethal necrosis, ClYVV/T27I still retained the ability to induce necrotic symptoms, but ClYVV/D193Y scarcely did so. The virus accumulation of ClYVV/D193Y was also lower than that of ClYVV no. 30. The mutations, T27I and D193Y, are located in a putative zinc finger domain and in one (N-terminal) of the two RNA binding domains, respectively, of HC-Pro. RNA-silencing suppression (RSS) activity of P1/HC-Pro in Nicotiana benthamiana was weakened by both mutations. Our results suggest a correlation between viral virulence and RSS function and the importance of the two domains in HC-Pro.

Spatial distribution of impurities in ZnO nanotubes characterized by cathodoluminescence

Low-energy cathodoluminescence (CL) imaging and spectroscopy technique was employed to study the impurity distribution in individual ZnO hexagonal nanotubes fabricated by metalorganic chemical vapor deposition on the sapphire (0001) substrate. The CL spectra at 10 K show that acceptor and donor impurities are incorporated in the ZnO nanotubes. CL monochromatic images indicate that the concentration of donor is higher at the bottom part and the distribution of acceptors is more inhomogeneous at the surface of the nanotubes. The non-uniform defects and impurities distributions are explained by unstable growth conditions and contamination from the environment. These results indicate that the low-energy CL is a very powerful method to investigate the inhomogeneity of luminescence properties in the individual nanostructures.

Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing

In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.