Adjoint Chiral Supermultiplets and Their Phenomenology

Matter fields in the MSSM are chiral supermultiplets in fundamental (or singlet) representations of the standard model gauge group. In this paper we introduce chiral superfields in the adjoint representation of $SU(3)_C$ and study the effective field theory and phenomenology of them. These states are well motivated by intersecting D-brane models in which additional massless adjoint chiral supermultiplets appear generically in the low energy spectrum. Although it has been pointed out that the existence of these additional fields may make it difficult to obtain asymptotic freedom, we demonstrate that this consideration does not rule out the existence of adjoints. The QCD gauge coupling can be perturbative up to a sufficiently high scale, and therefore a perturbative description for a D-brane model is valid. The full supersymmetric and soft SUSY breaking Lagrangians and the resulting renormalization group equations are given. Phenomenological aspects of the adjoint matter are also studied, including the decay and production processes. The similarity in gauge interaction between the adjoint fermion and gluino facilitates our study on these aspects. It is found that these adjoint multiplets can give detectable signals at colliders and satisfy the constraints from cosmology.Comment: 18 pages, 3 figures; minor corrections, references adde

Gluon GPDs and Exclusive Photoproduction of a Quarkonium in Forward Region

Forward photoproduction of $J/\psi$ can be used to extract Generalized Parton Distributions(GPD's) of gluons. We analyze the process at twist-3 level and study relevant classifications of twist-3 gluon GPD's. At leading power or twist-2 level the produced $J/\psi$ is transversely polarized. We find that at twist-3 the produced $J/\psi$ is longitudinally polarized. Our study shows that in high energy limit the twist-3 amplitude is only suppressed by the inverse power of the heavy quark mass relatively to the twist-2 amplitude. This indicates that the power correction to the cross-section of unpolarized $J/\psi$ can have a sizeable effect. We have also derived the amplitude of the production of $h_c$ at twist-3, but the result contains end-point singularities. The production of other quarkonia has been briefly discussed.Comment: Discussions of results are adde

Opaque Service Virtualisation: A Practical Tool for Emulating Endpoint Systems

Large enterprise software systems make many complex interactions with other services in their environment. Developing and testing for production-like conditions is therefore a very challenging task. Current approaches include emulation of dependent services using either explicit modelling or record-and-replay approaches. Models require deep knowledge of the target services while record-and-replay is limited in accuracy. Both face developmental and scaling issues. We present a new technique that improves the accuracy of record-and-replay approaches, without requiring prior knowledge of the service protocols. The approach uses Multiple Sequence Alignment to derive message prototypes from recorded system interactions and a scheme to match incoming request messages against prototypes to generate response messages. We use a modified Needleman-Wunsch algorithm for distance calculation during message matching. Our approach has shown greater than 99% accuracy for four evaluated enterprise system messaging protocols. The approach has been successfully integrated into the CA Service Virtualization commercial product to complement its existing techniques.Comment: In Proceedings of the 38th International Conference on Software Engineering Companion (pp. 202-211). arXiv admin note: text overlap with arXiv:1510.0142

Coil combination using linear deconvolution in k-space for phase imaging

Background: The combination of multi-channel data is a critical step for the imaging of phase and susceptibility contrast in magnetic resonance imaging (MRI). Magnitude-weighted phase combination methods often produce noise and aliasing artifacts in the magnitude images at accelerated imaging sceneries. To address this issue, an optimal coil combination method through deconvolution in k-space is proposed in this paper. Methods: The proposed method firstly employs the sum-of-squares and phase aligning method to yield a complex reference coil image which is then used to calculate the coil sensitivity and its Fourier transform. Then, the coil k-space combining weights is computed, taking into account the truncated frequency data of coil sensitivity and the acquired k-space data. Finally, combining the coil k-space data with the acquired weights generates the k-space data of proton distribution, with which both phase and magnitude information can be obtained straightforwardly. Both phantom and in vivo imaging experiments were conducted to evaluate the performance of the proposed method. Results: Compared with magnitude-weighted method and MCPC-C, the proposed method can alleviate the phase cancellation in coil combination, resulting in a less wrapped phase. Conclusions: The proposed method provides an effective and efficient approach to combine multiple coil image in parallel MRI reconstruction, and has potential to benefit routine clinical practice in the future

Coulomb drag in double quantum wells with a perpendicular magnetic field

Momentum transfer due to electron-electron interaction (Coulomb drag) between two quantum wells, separated by a distance $d$, in the presence of a perpendicular magnetic field, is studied at low temperatures. We find besides the well known Shubnikov-de Haas oscillations, which also appear in the drag effect, the momentum transfer is markedly enhanced by the magnetic field.Comment: 8 pages, Revtex, 4 Postscript figures are available upon request, Accepted by Mod. Phys. Lett.

Topology of Entanglement in Multipartite States with Translational Invariance

The topology of entanglement in multipartite states with translational invariance is discussed in this article. Two global features are foundby which one can distinguish distinct states. These are the cyclic unit and the quantised geometric phase. Furthermore the topology is indicated by the fractional spin. Finally a scheme is presented for preparation of these types of states in spin chain systems, in which the degeneracy of the energy levels characterises the robustness of the states with translational invariance.Comment: major revision. accepted by EPJ

Adhesive and degradative properties of human placental cytotrophoblast cells in vitro.

Human fetal development depends on the embryo rapidly gaining access to the maternal circulation. The trophoblast cells that form the fetal portion of the human placenta have solved this problem by transiently exhibiting certain tumor-like properties. Thus, during early pregnancy fetal cytotrophoblast cells invade the uterus and its arterial network. This process peaks during the twelfth week of pregnancy and declines rapidly thereafter, suggesting that the highly specialized, invasive behavior of the cytotrophoblast cells is closely regulated. Since little is known about the actual mechanisms involved, we developed an isolation procedure for cytotrophoblasts from placentas of different gestational ages to study their adhesive and invasive properties in vitro. Cytotrophoblasts isolated from first, second, and third trimester human placentas were plated on the basement membrane-like extracellular matrix produced by the PF HR9 teratocarcinoma cell line. Cells from all trimesters expressed the calcium-dependent cell adhesion molecule cell-CAM 120/80 (E-cadherin) which, in the placenta, is specific for cytotrophoblasts. However, only the first trimester cytotrophoblast cells degraded the matrices on which they were cultured, leaving large gaps in the basement membrane substrates and releasing low molecular mass 3H-labeled matrix components into the medium. No similar degradative activity was observed when second or third trimester cytotrophoblast cells, first trimester human placental fibroblasts, or the human choriocarcinoma cell lines BeWo and JAR were cultured on radiolabeled matrices. To begin to understand the biochemical basis of this degradative behavior, the substrate gel technique was used to analyze the cell-associated and secreted proteinase activities expressed by early, mid, and late gestation cytotrophoblasts. Several gelatin-degrading proteinases were uniquely expressed by early gestation, invasive cytotrophoblasts, and all these activities could be abolished by inhibitors of metalloproteinases. By early second trimester, the time when cytotrophoblast invasion rapidly diminishes in vivo, the proteinase pattern of the cytotrophoblasts was identical to that of term, noninvasive cells. These results are the first evidence suggesting that specialized, temporally regulated metalloproteinases are involved in trophoblast invasion of the uterus. Since the cytotrophoblasts from first trimester and later gestation placentas maintain for several days the temporally regulated degradative behavior displayed in vivo, the short-term cytotrophoblast outgrowth culture system described here should be useful in studying some of the early events in human place

Shot noise of inelastic tunneling through quantum dot systems

We present a theoretical analysis of the effect of inelastic electron scattering on current and its fluctuations in a mesoscopic quantum dot (QD) connected to two leads, based on a recently developed nonperturbative technique involving the approximate mapping of the many-body electron-phonon coupling problem onto a multichannel single-electron scattering problem. In this, we apply the B\"uttiker scattering theory of shot noise for a two-terminal mesoscopic device to the multichannel case with differing weight factors and examine zero-frequency shot noise for two special cases: (i) a single-molecule QD and (ii) coupled semiconductor QDs. The nonequilibrium Green's function method facilitates calculation of single-electron transmission and reflection amplitudes for inelastic processes under nonequilibrium conditions in the mapping model. For the single-molecule QD we find that, in the presence of the electron-phonon interaction, both differential conductance and differential shot noise display additional peaks as bias-voltage increases due to phonon-assisted processes. In the case of coupled QDs, our nonperturbative calculations account for the electron-phonon interaction on an equal footing with couplings to the leads, as well as the coupling between the two dots. Our results exhibit oscillations in both the current and shot noise as functions of the energy difference between the two QDs, resulting from the spontaneous emission of phonons in the nonlinear transport process. In the "zero-phonon" resonant tunneling regime, the shot noise exhibits a double peak, while in the "one-phonon" region, only a single peak appears.Comment: 10 pages, 6 figures, some minor changes, accepted by Phys. Rev.

Using schema transformation pathways for data lineage tracing

With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations