Left-right Symmetry Research Articles

Collapse and coexistence for a molecular braid with an attractive interaction component subject to mechanical forces

Dual mechanical braiding experiments provide a useful tool with which to investigate the nature of interactions between rod-like molecules, for instance actin and DNA. In conditions close to molecular condensation, one would expect an appearance of a local minimum in the interaction potential between the two molecules. We investigate this situation, introducing an attractive component into the interaction potential, using a model developed for describing such experiments. We consider both attractive interactions that do not depend on molecular structure and those which depend on a DNA-like helix structure. In braiding experiments, an attractive term may lead to certain effects. A local minimum may cause molecules to collapse from a loosely braided configuration into a tight one, occurring at a critical value of the moment applied about the axis of the braid. For a fixed number of braid pitches, this may lead to coexistence between the two braiding states, tight and loose. Coexistence implies certain proportions of the braid are in each state, their relative size depending on the number of braid pitches. This manifests itself as a linear dependence in numerically calculated quantities as functions of the number of braid pitches. Also, in the collapsed state, the braid radius stays roughly constant. Furthermore, if the attractive interaction is helix dependent, the left-right handed braid symmetry is broken. For a DNA like charge distribution, using the Kornyshev–Leikin interaction model, our results suggest that significant braid collapse and coexistence only occurs for left handed braids. Regardless of the interaction model, the study highlights the possible qualitative physics of braid collapse and coexistence; and the role helix specific forces might play, if important. The model could be used to connect other microscopic theories of interaction with braiding experiments.

Deconstruction, holography and emergent supersymmetry

We study a gauge theory in a 5D warped space via the dimensional deconstruction that a higher dimensional gauge theory is constructed from a moose of 4D gauge groups. By the AdS/CFT correspondence, a 5D warped gauge theory is dual to a 4D conformal field theory (CFT) with a global symmetry. As far as physics of the gauge theory, we obtain the one-to-one correspondence between each component of a moose of gauge groups and that of a CFT. We formulate a supersymmetric extension of deconstruction and explore the framework of natural supersymmetry in a 5D warped space — the super-symmetric Randall-Sundrum model with the IR-brane localized Higgs and bulk fermions — via the gauge moose. In this model, a supersymmetry breaking source is located at the end of the moose corresponding to the UV brane and the first two generations of squarks are decoupled. With left-right gauge symmetries in the bulk of the moose, we demonstrate realization of accidental or emergent supersymmetry of the Higgs sector in comparison with the proposed “Moose/CFT correspondence.”

Right-handed quark mixing in left-right symmetric theory.

We give exact formulas for the right-handed analog of the Cabibbo-Kobayashi-Maskawa (CKM) matrix in the minimal left-right symmetric theory, for the case when the left-right symmetry is generalized parity as in the original version of the theory. We derive its explicit form and give a physical reason for the known and surprising fact that the right-handed mixing angles are close to the CKM ones, in spite of the left-right symmetry being badly broken in nature. We exemplify our results on the production of the right-handed charged gauge boson and the computation of K(L)-K(S) mass difference.

Automated Multi-Contrast Brain Pathological Area Extraction from 2D MR Images

The aim of this work is to propose the fully automated pathological area extraction from multi-parametric 2D MR images of brain. The proposed method is based on multi-resolution symmetry analysis and automatic thresholding. The proposed algorithm first detects the presence of pathology and then starts its extraction. T2 images are used for the presence detection and the multi-contrast MRI is used for the extraction, concretely T2 and FLAIR images. The extraction is based on thresholding, where Otsu's algorithm is used for the automatic determination of the threshold. Since the method is based on symmetry, it works for both axial and coronal planes. In both these planes of healthy brain, the approximate left-right symmetry exists and it is used as the prior knowledge for searching the approximate pathology location. It is assumed that this area is not located symmetrically in both hemispheres, which is met in most cases. The detection algorithm was tested on 203 T2-weighted images and reached the true positive rate of 87.52% and true negative rate of 93.14%. The extraction algorithm was tested on 357 axial and 443 coronal real images from publicly available BRATS databases containing 3D volumes brain tumor patients. The results were evaluated by Dice Coefficient (axial: 0.85±0.11, coronal 0.82±0.18) and by Accuracy (axial: 0.96±0.05, coronal 0.94±0.09).

Double beta decay, lepton flavor violation, and collider signatures of left-right symmetric models with spontaneousD-parity breaking

We propose a class of left-right symmetric models (LRSMs) with spontaneous D parity breaking, where SU(2)_R breaks at the TeV scale while discrete left-right symmetry breaks around 10^9 GeV. By embedding this framework in a non-supersymmetric SO(10) Grand Unified Theory (GUT) with Pati-Salam symmetry as the highest intermediate breaking step, we obtain g_R / g_L ~ 0.6 between the right- and left-handed gauge couplings at the TeV scale. This leads to a suppression of beyond the Standard Model phenomena induced by the right-handed gauge coupling. Here we focus specifically on the consequences for neutrinoless double beta decay, low energy lepton flavour violation and LHC signatures due to the suppressed right handed currents. Interestingly, the reduced g_R allows us to interpret an excess of events observed recently in the range of 1.9 TeV to 2.4 TeV by the CMS group at the LHC as the signature of a right handed gauge boson in LRSMs with spontaneous D parity breaking. Moreover, the reduced right-handed gauge coupling also strongly suppresses the non-standard contribution of heavy states to the neutrinoless double beta decay rate as well as the amplitude of low energy lepton flavour violating processes. In a dominant type-II Seesaw mechanism of neutrino mass generation, we find that both sets of observables provide stringent and complimentary bounds which make it challenging to observe the scenario at the LHC.

Fluid Dynamics of Flow Driven by Nodal Cilia Precessing Non-circular Cones

Nodal cilia play an important role in the left-right symmetry breaking at the early stage of the mammal embryos and show an apparent rotational motion. This study is about the ow induced by cilia sweeping out circular/elliptical cones above a no-slip plane in the low Reynolds number regime. Using the regularized Stokeslet method, we examine the properties of ows generated by a single cilium and multiple cilia, especially two cilia, which are assumed to be anchored to the embryonic heart wall. For a short-term Lagrangian uid tracer trajectory, epicycles are presented as a nodal cilium precesses in either a circular cone or a non-circular cone shape. For the longterm behavior, the trajectory is periodic around both the circular and elliptical cones. Compared to the circular cone cases, the vertical variances are enhanced in elliptical cone cases. Besides tracer trajectories, uid velocity elds are presented to demonstrate the ow structure. When

Characterization of 2D rational local conformal nets and its boundary conditions: the maximal case

Let \mathcal A be a completely rational local Möbius covariant net on S^1 , which describes a set of chiral observables. We show that local Möbius covariant nets \mathcal B_2 on 2D Minkowski space which contains \mathcal A as chiral left-right symmetry are in one-to-one correspondence with Morita equivalence classes of Q-systems in the unitary modular tensor category \mathrm{DHR}(\mathcal A) . The Möbius covariant boundary conditions with symmetry \mathcal A of such a net \mathcal B_2 are given by the Q-systems in the Morita equivalence class or by simple objects in the module category modulo automorphisms of the dual category. We generalize to reducible boundary conditions. To establish this result we define the notion of Morita equivalence for Q-systems (special symmetric \ast -Frobenius algebra objects) and non-degenerately braided subfactors. We prove a conjecture by Kong and Runkel, namely that Rehren's construction (generalized Longo–Rehren construction, \alpha -induction construction) coincides with the categorical full center. This gives a new view and new results for the study of braided subfactors.

Evaluation the immediate effects of bracing on kinetic parameters in adolescent idiopathic scoliosis patients

Background Idiopathic scoliosis induces change in coordination between body segments, spinal anatomy, left-right trunk symmetry and gait pattern. Various treatment methods have being used for scoliosis which includes: physical therapy, occupational therapy, osteopathic therapy, casting, bracing and surgery. However, using brace is a commonly used method in this regard. Although, the influence of brace to reduce the scoliosis curve has been investigated in lots of research studies, there is not enough research regarding the influence of brace on performance of scoliotic subjects while walking and standing. Therefore, the purpose of this study was to evaluate the immediate effect of brace on stability performance of scoliotic subjects and the symmetry of the ground reaction force applied on the right and left feet while walking. Method Then girls aged between 8 and 12 years were recruited in this study. The gait analysis was assessed using a three-dimensional motion analysis and a force plate (Kistler) in two conditions, with and without Boston brace. Moreover their stability was evaluated by use of force plate. The difference of kinetic and stability parameters between two conditions(with and without Boston brace)was checked by use of paired T-test. Results

An SO(10) × SO(10)′ model for common origin of neutrino masses, ordinary and dark matter-antimatter asymmetries

We propose an SO(10) × SO(10)′ model to simultaneously realize a seesaw for Dirac neutrino masses and a leptogenesis for ordinary and dark matter-antimatter asymmetries. A (16 × 1̄6̄′)H scalar crossing the SO(10) and SO(10)′ sectors plays an essential role in this seesaw-leptogenesis scenario. As a result of lepton number conservation, the lightest dark nucleon as the dark matter particle should have a determined mass around 15 GeV to explain the comparable fractions of ordinary and dark matter in the present universe. The (16 × 1̄6̄′)H scalar also mediates a U(1)em × U(1)′em kinetic mixing after the ordinary and dark left-right symmetry breaking so that we can expect a dark nucleon scattering in direct detection experiments and/or a dark nucleon decay in indirect detection experiments. Furthermore, we can impose a softly broken mirror symmetry to simplify the parameter choice.

Production and decay rates of excited leptons in a left-right symmetric scenario

We merge two leading beyond standard model scenarios, namely compositeness and left-right symmetry, and probe the resulting collider signatures in the leptonic case. The constraints on composite models for fermions leave open the possibility of vectorlike excitations of standard model fermions. Here we consider the possibility of low scale left-right gauge symmetry $SU(2{)}_{R}\ifmmode\times\else\texttimes\fi{}SU(2{)}_{L}\ifmmode\times\else\texttimes\fi{}U(1{)}_{B\ensuremath{-}L}$, with the simplifying assumption that the rightlike excited sector of fermions is significantly heavier than the excitations of the left chiral fermions. It is found that the right-hand currents still contribute to observable processes, and alter the existing bounds on the scale of compositeness. The cross section times branching ratio of the photon decay channel is strongly depressed, bringing down the exclusion limit of the mass of excited electrons from about 2 TeV to below 1 TeV. On the other hand, cross section times branching ratio of the Z decay channel is significantly enhanced and remains greater than that of the photon channel. We thus propose analyzing the Z decay channel in existing collider data in order to search for signature of left-right symmetry as well as excited leptons with masses above 1 TeV.

Notes on the distribution of and the occurrence of asymmetrical underleaves associated with left-right symmetry in Mastigolejeunea virens (Ångstr.) Steph. (Lejeuneaceae).

Mastigolejeunea (Spruce 1884: 100) Stephani (1889: 257) is a pantropical genus with 16 extant species (Sukkharak & Gradstein 2014a). The centre of diversity is Southeast Asia with 10 species occurring in the region. This genus is very similar to Thysananthus Lindenb. in Lehmann (1844: 24) and the two genera can be separated by the presence of an entire perianth in Mastigolejeunea and toothed in Thysananthus (Sukkharak 2014; Sukkharak & Gradstein 2014a). Three species, M. humilis (Gottsche in Gottsche et al. 1845: 299) Schiffner (1893: 129), M. indica Stephani (1912: 776) and M. repleta (Taylor 1846: 392) Evans (1902: 131), have so far been reported in China (He 1997; Mizutani 1986; Piippo 1990). In the course of our studies on Chinese Ptychanthoideae Mizutani (1961: 146), we found a new record of M. virens (Ångström 1873: 131) Stephani (1912: 776) for the ptychanthoid flora of China. Mastigolejeunea virens has been reported from Australia, Indomalesia, Seychelles and the tropical Pacific region (Sukkharak & Gradstein 2014a). We report the species here for Hainan, China, which is its northernmost locality. In addition, we newly report the occurrence of asymmetrical underleaves associated with left-right symmetry in M. virens based on our study of specimens collected in China and Thailand.

Triplets of Closely Embedded Hilbert Spaces

We obtain a general concept of triplet of Hilbert spaces with closed (unbounded) embeddings instead of continuous (bounded) ones. We provide a model and an abstract theorem as well for a triplet of closely embedded Hilbert spaces associated to positive selfadjoint operator H, that is called the Hamiltonian of the system, which is supposed to be one-to-one but may not have a bounded inverse. Existence and uniqueness results, as well as left-right symmetry, for these triplets of closely embedded Hilbert spaces are obtained. We motivate this abstract theory by a diversity of problems coming from homogeneous or weighted Sobolev spaces, Hilbert spaces of holomorphic functions, and weighted L 2 spaces. An application to weak solutions for a Dirichlet problem associated to a class of degenerate elliptic partial differential equations is presented. In this way, we propose a general method of proving the existence of weak solutions that avoids coercivity conditions and Poincaré–Sobolev type inequalities.

Left-right patterning in the C. elegans embryo: Unique mechanisms and common principles.

The development of bilateral symmetry during the evolution of species probably 600 million years ago brought about several important innovations: It fostered efficient locomotion, streamlining and favored the development of a central nervous system through cephalization. However, to increase their functional capacities, many organisms exhibit chirality by breaking their superficial left-right (l-r) symmetry, which manifests in the lateralization of the nervous system or the l-r asymmetry of internal organs. In most bilateria, the mechanisms that maintain consistent l-r asymmetry throughout development are poorly understood. This review highlights insights into mechanisms that couple early embryonic l-r symmetry breaking to subsequent l-r patterning in the roundworm Caenorhabditis elegans. A recently identified strategy for l-r patterning in the early C. elegans embryo is discussed, the spatial separation of midline and anteroposterior axis, which relies on a rotational cellular rearrangement and non-canonical Wnt signaling. Evidence for a general relevance of rotational/torsional rearrangements during organismal l-r patterning and for non-canonical Wnt signaling/planar cell polarity as a common signaling mechanism to maintain l-r asymmetry is presented.

StrongPinvariance, neutron electric dipole moment, and minimal left-right parity at LHC

In the minimal left-right model the choice of left-right symmetry is twofold: either generalized parity $\mathcal{P}$ or charge conjugation $\mathcal{C}$. In the minimal model with spontaneously broken strict $\mathcal{P}$, a large tree-level contribution to strong $CP$ violation can be computed in terms of the spontaneous phase $\ensuremath{\alpha}$. Searches for the neutron electric dipole moments then constrain the size of $\ensuremath{\alpha}$. Following the latest update on indirect $CP$ violation in the kaon sector, a bound on ${W}_{R}$ mass at 20 TeV is set. Possible ways out of this bound require a further hypothesis, either a relaxation mechanism or explicit breaking of $\mathcal{P}$. To this end, the chiral loop of the neutron electric dipole moment at next-to-leading order is recomputed and provides an estimate of the weak contribution. Combining this constraint with other $CP$-violating observables in the kaon sector allows for ${M}_{{W}_{R}}\ensuremath{\gtrsim}3\text{ }\text{ }\mathrm{TeV}$. On the other hand, $\mathcal{C}$ symmetry is free from such constraints, leaving the right-handed scale within the experimental reach.

Natural supersymmetry in warped space

We explore the possibility of solving the hierarchy problem by combining the paradigms of supersymmetry and compositeness. Both paradigms are under pressure from the results of the Large Hadron Collider (LHC), and combining them allows both a higher confinement scale — due to effective supersymmetry in the low energy theory — and heavier superpartners — due to the composite nature of the Higgs boson — without sacrificing naturalness. The supersymmetric Randall-Sundrum model provides a concrete example where calculations are possible, and we pursue a realistic model in this context. With a few assumptions, we are led to a model with bulk fermions, a left-right gauge symmetry in the bulk, and supersymmetry breaking on the UV brane. The first two generations of squarks are decoupled, reducing LHC signatures but also leading to quadratic divergences at two loops. The model predicts light W ′ and Z ′ gauge bosons, and present LHC constraints on exotic gauge bosons imply a high confinement scale and mild tuning from the quadratic divergences, but the model is otherwise viable. We also point out that R-parity violation can arise naturally in this context.

Signal of right-handed charged gauge bosons at the LHC?

We point out that the recent excess observed in searches for a right-handed gauge boson W_R at CMS can be explained in a left-right symmetric model with D parity violation. In a class of SO(10) models, in which D parity is broken at a high scale, the left-right gauge symmetry breaking scale is naturally small, and at a few TeV the gauge coupling constants satisfy g_R ~ 0.6 g_L. Such models therefore predict a right-handed charged gauge boson W_R in the TeV range with a suppressed gauge coupling as compared to the usually assumed manifest left-right symmetry case g_R = g_L. The recent CMS data show excess events which are consistent with the cross section predicted in the D parity breaking model for 1.9 TeV < M_{W_R} < 2.4 TeV. If the excess is confirmed, it would in general be a direct signal of new physics beyond the Standard Model at the LHC. A TeV scale W_R would for example not only rule out SU(5) grand unified theory models. It would also imply B-L violation at the TeV scale, which would be the first evidence for baryon or lepton number violation in nature and it has strong implications on the generation of neutrino masses and the baryon asymmetry in the Universe.

A parity breaking Ising chain Hamiltonian as a Brownian motor

We consider the translationally invariant but parity (left-right symmetry) breaking Ising chain Hamiltonian and let this system evolve by Kawasaki spin exchange dynamics. Monte Carlo simulations show that perturbations forcing this system off equilibrium make it act as a Brownian molecular motor which, in the lattice gas interpretation, transports particles along the chain. We determine the particle current under various different circumstances, in particular as a function of the ratio and of the conserved magnetization . The symmetry of the U3 term in the Hamiltonian is discussed.

Quasiparticle trapping, Andreev level population dynamics, and charge imbalance in superconducting weak links

We present a comprehensive theoretical framework for the Andreev bound state population dynamics in superconducting weak links. Contrary to previous works, our approach takes into account the generated nonequilibrium distribution of the continuum quasiparticle states in a self-consistent way. As application of our theory, we show that the coupling of the superconducting contact to environmental phase fluctuations induces a charge imbalance of the continuum quasiparticle population. This imbalance is due to the breaking of the left-right symmetry in the rates connecting continuum quasiparticles and the Andreev bound state system, and causes a quasiparticle current on top of the Josephson current in a ring geometry. We evaluate the phase dependence of the quasiparticle current for realistic choices of the model parameters. Our theory also allows one to analyze the quantum coherent evolution of the system from an arbitrary initial state.

Flavour models with three Higgs generations

We construct models with a spontaneously broken $SU(3)_F$ flavour symmetry where three generations of Higgs multiplets transform in a flavour-triplet representation. The models are embedded in a supersymmetric Pati-Salam GUT framework, which includes left-right symmetry. We study the possible flavon representations and show that a model with flavons in the decuplet representation is able to reproduce the hierarchy structure of the quark and lepton mass and mixing matrices. This result requires no additional structure or fine-tunings except for an extra $Z_4$ discrete symmetry in the superpotential.

Western Saudi adolescent age estimation utilising third molar development.

Objective:The aim of this study was to establish reference data on third molar morphology/development for age estimation in Western Saudi adolescents, between ages 14 and 23 years of old.Materials and Methods:The orthopantomograms of 130 individuals (males and females), were examined, and the stage of third molar development were evaluated.Results:Mean ages, standard deviations, and percentile distributions are presented for each stage of development. The mean estimated age for all participants (n = 130) was 219.7 months, and this differed significantly (P < 0.05) from the mean chronological age (226.5 months). Deviations of predicted age from real age showed 28.5% of all participants had their age estimated within 1 year (±12 months) of their chronological age. Most (43%) had their age underestimated by more than 12 months and the remaining 28.5% had their age overestimated by more than 12 months of their chronological age. Differences in left-right symmetry information of third molars were detected and were higher in the maxilla (92%) than in the mandible (82%). For all molars reaching stage “H” most individuals (males and females) were over the age 18 years of old. Males reach the developmental stages earlier than females.Conclusion:Third molar tooth development can be reliably used to generate mean age and the estimated age range for an individual of unknown chronological age. Further studies with large populations are needed for better statistical results.