Canonical Formalism for a 2n-Dimensional Model with Topological Mass Generation

The four-dimensional model with topological mass generation that was found by Dvali, Jackiw and Pi has recently been generalized to any even number of dimensions (2n-dimensions) in a nontrivial manner in which a Stueckelberg-type mass term is introduced [S. Deguchi and S. Hayakawa, Phys. Rev. D 77, 045003 (2008), arXiv:0711.1446]. The present paper deals with a self-contained model, called here a modified hybrid model, proposed in this 2n-dimensional generalization and considers the canonical formalism for this model. For the sake of convenience, the canonical formalism itself is studied for a model equivalent to the modified hybrid model by following the recipe for treating constrained Hamiltonian systems. This formalism is applied to the canonical quantization of the equivalent model in order to clarify observable and unobservable particles in the model. The equivalent model (with a gauge-fixing term) is converted to the modified hybrid model (with a corresponding gauge-fixing term) in a Becchi-Rouet-Stora-Tyutin (BRST)-invariant manner. Thereby it is shown that the Chern-Pontryagin density behaves as an observable massive particle (or field). The topological mass generation is thus verified at the quantum-theoretical level.Comment: 29 pages, no figures, minor corrections, published versio

Lasing from a single quantum wire

A laser with an active volume consisting of only a single quantum wire in the 1-dimensional (1-D) ground state is demonstrated. The single wire is formed quantum-mechanically at the T-intersection of a 14 nm Al_{0.07}Ga_{0.93}As quantum well and a 6 nm GaAs quantum well, and is embedded in a 1-D single-mode optical waveguide. We observe single-mode lasing from the quantum wire ground state by optical pumping. The laser operates from 5 to 60 K, and has a low threshold pumping power of 5 mW at 5 K.Comment: 4 pages including 4 figure

Imaging of emission patterns in a T-shaped quantum wire laser

Spatially and spectrally resolved microscopic images of spontaneous and stimulated emissions are imaged at the mirror facets of a GaAs T-shaped quantum wire laser with high uniformity. Laser emission from the one-dimensional ground state reveals a circular image located at the core of a T-shaped optical waveguide but significantly smaller in area than the low power spontaneous emission from the same waveguide. These images unambiguously allow assignment of all spontaneous and laser emissions to the wire ground state and respective intersecting wells in the structure.Comment: 4 pages, 3 figure

Assured and Correct Dynamic Update of Controllers

We present a general approach to specifying correctness criteria for dynamic update and a technique for automatically computing a controller that handles the transition from the old to the new specification, assuring that the system will reach a state in which such a transition can correctly occur. Indeed, using controller synthesis we show how to automatically build a controller that guarantees both progress towards update and safe update.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Assured and Correct Dynamic Update of Controllers

We present a general approach to specifying correctness criteria for dynamic update and a technique for automatically computing a controller that handles the transition from the old to the new specification, assuring that the system will reach a state in which such a transition can correctly occur. Indeed, using controller synthesis we show how to automatically build a controller that guarantees both progress towards update and safe update.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Superconductivity of the Sr2Ca12Cu24O41Sr_2 Ca_{12} Cu_{24} O_{41} spin ladder system: Are the superconducting pairing and the spin-gap formation of the same origin?

Pressure-induced superconductivity in a spin-ladder cuprate Sr$_2$Ca$_{12}$Cu$_{24}$O$_{41}$ has not been studied on a microscopic level so far although the superconductivity was already discovered in 1996. We have improved high-pressure technique with using a large high-quality crystal, and succeeded in studying the superconductivity using $^{63}$Cu nuclear magnetic resonance (NMR). We found that anomalous metallic state reflecting the spin-ladder structure is realized and the superconductivity possesses a s-wavelike character in the meaning that a finite gap exists in the quasi-particle excitation: At pressure of 3.5GPa we observed two excitation modes in the normal state from the relaxation rate $T_1^{-1}$. One gives rise to an activation-type component in $T_1^{-1}$, and the other $T$-linear component linking directly with the superconductivity. This gapless mode likely arises from free motion of holon-spinon bound states appearing by hole doping, and the pairing of them likely causes the superconductivity.Comment: to be published in Phys. Rev. Let

Issue Small Satellites

Small satellite is a disruptive technology in space industries. Traditionally, space industries were dominated by satellites which have thousands of kilograms and are bulky and expensive. Small satellites denote a new generation of miniaturized satellites which, by taking advantages of modern technologies (e.g., integrated circuits, digital signal processing, MEMS, and additive manufacturing), can achieve a significant reduction in volume, mass, development time, and cost of satellites. During recent decades, small satellites, including CubeSats, NanoSats, MiniSats, and MicroSats, have undergone rapid developments, and are playing an increasingly larger role in exploration, technology demonstration, scientific research, and education. These miniature satellites provide a low-cost platform for missions, including planetary space exploration, Earth observations, fundamental Earth and space science, and developing precursor science instruments like laser communications and millimeter-wave communications for intersatellite and intrasatellite links, and autonomous movement capabilities. They also allow educators an inexpensive means to engage students in all phases of satellite development, operation, and exploitation through real-world, hands-on research and development experience on rideshare launch opportunities. A number of miniaturized satellites can form spaceborne wireless sensor networks in the space, which are also going to play an important role in Internet of Space (IoS) of the futur

Complementary Dendritic Cell–activating Function of CD8+ and CD4+ T Cells: Helper Role of CD8+ T Cells in the Development of T Helper Type 1 Responses

Dendritic cells (DCs) activated by CD40L-expressing CD4+ T cells act as mediators of “T helper (Th)” signals for CD8+ T lymphocytes, inducing their cytotoxic function and supporting their long-term activity. Here, we show that the optimal activation of DCs, their ability to produce high levels of bioactive interleukin (IL)-12p70 and to induce Th1-type CD4+ T cells, is supported by the complementary DC-activating signals from both CD4+ and CD8+ T cells. Cord blood– or peripheral blood–isolated naive CD8+ T cells do not express CD40L, but, in contrast to naive CD4+ T cells, they are efficient producers of IFN-γ at the earliest stages of the interaction with DCs. Naive CD8+ T cells cooperate with CD40L-expressing naive CD4+ T cells in the induction of IL-12p70 in DCs, promoting the development of primary Th1-type CD4+ T cell responses. Moreover, the recognition of major histocompatibility complex class I–presented epitopes by antigen-specific CD8+ T cells results in the TNF-α– and IFN-γ–dependent increase in the activation level of DCs and in the induction of type-1 polarized mature DCs capable of producing high levels of IL-12p70 upon a subsequent CD40 ligation. The ability of class I–restricted CD8+ T cells to coactivate and polarize DCs may support the induction of Th1-type responses against class I–presented epitopes of intracellular pathogens and contact allergens, and may have therapeutical implications in cancer and chronic infections

Paediatric HIV and elimination of mother-to-child transmission of HIV in the ASEAN region: a call to action

Recent achievements in scaling up paediatric antiretroviral therapy (ART) have changed the life of children living with HIV, who now stay healthy and live longer lives. However, as it becomes more of a chronic infection, a range of new problems have begun to arise. These include the disclosure of HIV serostatus to children, adherence to ART, long-term toxicities of antiretroviral drugs and their sexual and reproductive health, which are posing significant challenges to the existing health systems caring for children with HIV with limited resources, experiences and capacities. While intensified efforts and actions to improve care and treatment for these children are needed, it is crucial to accelerate the prevention of mother-to-child transmission (PMTCT) of HIV, which is the main cause of paediatric HIV in the ASEAN region so as to eliminate the fundamental cause of the problem. This report argues that given over 70% of women have access to at least one antenatal care visit in the region and acceptance of HIV testing after receiving counselling on PMTCT could be as high as 90%, there is an opportunity to strengthen PMTCT services and eventually eliminate new paediatric HIV infections in the ASEAN countries