Conformal topological Yang-Mills theory and de Sitter holography

A new topological conformal field theory in four Euclidean dimensions is constructed from N=4 super Yang-Mills theory by twisting the whole of the conformal group with the whole of the R-symmetry group, resulting in a theory that is conformally invariant and has two conformally invariant BRST operators. A curved space generalisation is found on any Riemannian 4-fold. This formulation has local Weyl invariance and two Weyl-invariant BRST symmetries, with an action and energy-momentum tensor that are BRST-exact. This theory is expected to have a holographic dual in 5-dimensional de Sitter space.Comment: 34 pages, AMSTex, Reference adde

Metabolic syndrome before puberty: Myth or reality?

Metabolic syndrome (MetS) is defined as a cluster of alterations related with insulin resistance (obesity, dyslipidemia, hypertension, and impaired glucose metabolism), which are associated with a higher risk of cardiovascular disease in adults. Several definitions have been proposed for older children and adolescents. However, no definitions have been made in accordance with pubertal status, and those in prepubertal state have not received attention enough, despite there are data suggesting the early presence of risk factors. The new insights concerning healthy and unhealthy metabolic status or the addition of novel metabolic risk biomarkers, may contribute to the knowledge about the development of MetS in children. This manuscript reviews the available evidence on MetS during childhood, focusing on the prepubertal period

Clinical and Molecular Assessment in a Female with Fragile X Syndrome and Tuberous Sclerosis.

Fragile X syndrome (FXS) and tuberous sclerosis (TSC) are genetic disorders that result in intellectual disability and an increased prevalence of autism spectrum disorders (ASD). While the clinical presentation of each disorder is distinct, the molecular causes are linked to a disruption in the mTORC1 (mammalian Target of Rapamycin Complex 1) and ERK1/2 (Extracellular signal-Regulated Kinase) signaling pathways. We assessed the clinical and molecular characteristics of an individual seen at the UC Davis MIND Institute with a diagnosis of FXS and TSC. Clinical evaluation of physical, behavioral, and cognitive impairments were performed. Additionally, total and phosphorylated proteins along the mTORC1 and ERK1/2 pathways were measured in primary fibroblast cell lines from the proband. In this case the phenotypic effects that result in a human with both FXS and TSC are shown to be severe. Changes in mTORC1 and ERK1/2 signaling proteins and global protein synthesis were not found to be noticeably different between four cohorts (typically developing, FMR1 full mutation, FMR1 full mutation and TSC1 loss of function mutation, and TSC1 loss of function mutation); however cohort sizes prevented stringent comparisons. It has previously been suggested that disruption of the mTORC1 pathway was reciprocal in TSC and FXS double knock-out mouse models so that the regulation of these pathways were more similar to wild-type mice compared to mice harboring a Fmr1(-/y) or Tsc2(-/+) mutation alone. However, in this first reported case of a human with a diagnosis of both FXS and TSC, substantial clinical impairments, as a result of these two disorders were observed. Differences in the mTORC and ERK1/2 pathways were not clearly established when compared between individuals with either disorder, or both

Geometric Actions for D-Branes and M-Branes

New forms of Born-Infeld, D-brane and M theory five-brane actions are found which are quadratic in the abelian field strength. The gauge fields couple both to a background or induced metric and a new auxiliary metric, whose elimination reproduces the non-polynomial Born-Infeld action. This is similar to the introduction of an auxiliary metric to simplify the Nambu-Goto string action. This simplifies the quantisation and dualisation of the gauge fields.Comment: LaTeX, 9 pages, no figures. Minor corrections; version to appear in Physics Letters

Gravitational Duality in MacDowell-Mansouri Gauge Theory

Strong-weak duality invariance can only be defined for particular sectors of supersymmetric Yang-Mills theories. Nevertheless, for full non-Abelian non-supersymmetric theories, dual theories with inverted couplings, have been found. We show that an analogous procedure allows to find the dual action to the gauge theory of gravity constructed by the MacDowell-Mansouri model plus the superposition of a $\Theta$ term.Comment: 9 pages, LaTeX, no figure

Uniqueness of M-theory PP-Wave Background with Extra Supersymmetries

We examine Killing spinor equations of the general eleven-dimensional pp-wave backgrounds, which contain a scalar H(x^m,x^-) in the metric and a three-form \xi(x^m,x^-) in the flux. Considering non-harmonic extra Killing spinors, we show that if the backgrounds admit at least one extra Killing spinor in addition to the standard 16 Killing spinors, they can be reduced to the form with H=A_{mn}(x^-)x^mx^n and \xi(x^-) modulo coordinate transformations. We further examine the cases in which the extra Killing spinor is characterized by a set of Cartan matrices. The super-isometry algebras of the resulting backgrounds are also derived.Comment: 25 pages, LaTeX2e, comments added, version to appear in PR

Dihydroergotamine inhibits the vasodepressor sensory CGRPergic outflow by prejunctional activation of α2-adrenoceptors and 5-HT1 receptors

Background: Dihydroergotamine (DHE) is an antimigraine drug that produces cranial vasoconstriction and inhibits trigeminal CGRP release; furthermore, it inhibits the vasodepressor sensory CGRPergic outflow, but the receptors involved remain unknown. Prejunctional activation of α2A/2C-adrenergic, serotonin 5-HT1B/1F, or dopamine D2-like receptors results in inhibition of this CGRPergic outflow. Since DHE displays affinity for these receptors, this study investigated the pharmacological profile of DHE-induced inhibition of the vasodepressor sensory CGRPergic outflow. Methods: Pithed rats were pretreated i.v. with hexamethonium (2 mg/kg·min) followed by continuous infusions of methoxamine (20 μg/kg·min) and DHE (3.1 μg/kg·min). Then, stimulus-response curves (spinal electrical stimulation; T9-T12) or dose-response curves (i.v. injections of α-CGRP) resulted in frequency-dependent or dose-dependent decreases in diastolic blood pressure. Results: DHE inhibited the vasodepressor responses to electrical stimulation (0.56–5.6 Hz), without affecting those to i.v. α-CGRP (0.1–1 μg/kg). This inhibition by DHE (not produced by the methoxamine infusions): (i) was abolished by pretreatment with the combination of the antagonists rauwolscine (α2-adrenoceptor; 310 μg/kg) plus GR127935 (5-HT1B/1D; 31 μg/kg); and (ii) remained unaffected after rauwolscine (310 μg/kg), GR127935 (31 μg/kg) or haloperidol (D2-like; 310 μg/kg) given alone, or after the combination of rauwolscine plus haloperidol or GR127935 plus haloperidol at the aforementioned doses. Conclusion: DHE-induced inhibition of the vasodepressor sensory CGRPergic outflow is mainly mediated by prejunctional rauwolscine-sensitive α2-adrenoceptors and GR127935-sensitive 5-HT1B/1D receptors, which correlate with α2A/2C-adrenoceptors and 5-HT1B receptors, respectively. These findings suggest that DHE-induced inhibition of the perivascular sensory CGRPergic outflow may facilitate DHE’s vasoconstrictor properties resulting in an increased vascular resistance

Vortices, Instantons and Branes

The purpose of this paper is to describe a relationship between the moduli space of vortices and the moduli space of instantons. We study charge k vortices in U(N) Yang-Mills-Higgs theories and show that the moduli space is isomorphic to a special Lagrangian submanifold of the moduli space of k instantons in non-commutative U(N) Yang-Mills theories. This submanifold is the fixed point set of a U(1) action on the instanton moduli space which rotates the instantons in a plane. To derive this relationship, we present a D-brane construction in which the dynamics of vortices is described by the Higgs branch of a U(k) gauge theory with 4 supercharges which is a truncation of the familiar ADHM gauge theory. We further describe a moduli space construction for semi-local vortices, lumps in the CP(N) and Grassmannian sigma-models, and vortices on the non-commutative plane. We argue that this relationship between vortices and instantons underlies many of the quantitative similarities shared by quantum field theories in two and four dimensions.Comment: 32 Pages, 4 Figure

Amelioration of non-motor dysfunctions after transplantation of human dopamine neurons in a model of Parkinson's disease

Background Patients suffering from Parkinson's disease (PD) display cognitive and neuropsychiatric dysfunctions, especially with disease progression. Although these impairments have been reported to impact more heavily upon a patient's quality of life than any motor dysfunctions, there are currently no interventions capable of adequately targeting these non-motor deficits. Objectives Utilizing a rodent model of PD, we investigated whether cell replacement therapy, using intrastriatal transplants of human-derived ventral mesencephalic (hVM) grafts, could alleviate cognitive and neuropsychiatric, as well as motor, dysfunctions. Methods Rats with unilateral 6-hydroxydopamine lesions to the medial forebrain bundle were tested on a complex operant task that dissociates motivational, visuospatial and motor impairments sensitive to the loss of dopamine. A subset of lesioned rats received intrastriatal hVM grafts of ~ 9 weeks gestation. Post-graft, rats underwent repeated drug-induced rotation tests and were tested on two versions of the complex operant task, before post-mortem analysis of the hVM tissue grafts. Results Post-graft behavioural testing revealed that hVM grafts improved non-motor aspects of task performance, specifically visuospatial function and motivational processing, as well as alleviating motor dysfunctions. Conclusions We report the first evidence of human VM cell grafts alleviating both non-motor and motor dysfunctions in an animal model of PD. This intervention, therefore, is the first to improve cognitive and neuropsychiatric symptoms long-term in a model of PD