616 research outputs found
Global aspects of the space of 6D N = 1 supergravities
We perform a global analysis of the space of consistent 6D quantum gravity
theories with N = 1 supersymmetry, including models with multiple tensor
multiplets. We prove that for theories with fewer than T = 9 tensor multiplets,
a finite number of distinct gauge groups and matter content are possible. We
find infinite families of field combinations satisfying anomaly cancellation
and admitting physical gauge kinetic terms for T > 8. We find an integral
lattice associated with each apparently-consistent supergravity theory; this
lattice is determined by the form of the anomaly polynomial. For models which
can be realized in F-theory, this anomaly lattice is related to the
intersection form on the base of the F-theory elliptic fibration. The condition
that a supergravity model have an F-theory realization imposes constraints
which can be expressed in terms of this lattice. The analysis of models which
satisfy known low-energy consistency conditions and yet violate F-theory
constraints suggests possible novel constraints on low-energy supergravity
theories.Comment: 41 pages, 1 figur
6D supergravity without tensor multiplets
We systematically investigate the finite set of possible gauge groups and
matter content for N = 1 supergravity theories in six dimensions with no tensor
multiplets, focusing on nonabelian gauge groups which are a product of SU(N)
factors. We identify a number of models which obey all known low-energy
consistency conditions, but which have no known string theory realization. Many
of these models contain novel matter representations, suggesting possible new
string theory constructions. Many of the most exotic matter structures arise in
models which precisely saturate the gravitational anomaly bound on the number
of hypermultiplets. Such models have a rigid symmetry structure, in the sense
that there are no moduli which leave the full gauge group unbroken.Comment: 31 pages, latex; v2, v3: minor corrections, references adde
5d quivers and their AdS(6) duals
We consider an infinite class of 5d supersymmetric gauge theories involving
products of symplectic and unitary groups that arise from D4-branes at orbifold
singularities in Type I' string theory. The theories are argued to be dual to
warped AdS(6)x S4/Zn backgrounds in massive Type IIA supergravity. In
particular, this demonstrates the existence of supersymmetric 5d fixed points
of quiver type. We analyze the spectrum of gauge fields and charged states in
the supergravity dual, and find a precise agreement with the symmetries and
charged operators in the quiver theories. We also comment on other brane
objects in the supergravity dual and their interpretation in the field
theories.Comment: 29 pages, 15 figure
Correction: CD93 is expressed on chronic myeloid leukemia stem cells and identifies a quiescent population which persists after tyrosine kinase inhibitor therapy
Correction to: Leukemia
https://doi.org/10.1038/s41375-019-0684-
Associations of sedentary behaviour, physical activity, blood pressure and anthropometric measures with cardiorespiratory fitness in children with cerebral palsy
Background - Children with cerebral palsy (CP) have poor cardiorespiratory fitness in comparison to their peers with typical development, which may be due to low levels of physical activity. Poor cardiorespiratory fitness may contribute to increased cardiometabolic risk. Purpose - The aim of this study was to determine the association between sedentary behaviour, physical activity and cardiorespiratory fitness in children with CP. An objective was to determine the association between cardiorespiratory fitness, anthropometric measures and blood pressure in children with CP. Methods- This study included 55 ambulatory children with CP [mean (SD) age 11.3 (0.2) yr, range 6-17 yr; Gross Motor Function Classification System (GMFCS) levels I and II]. Anthropometric measures (BMI, waist circumference and waist-height ratio) and blood pressure were taken. Cardiorespiratory fitness was measured using a 10 m shuttle run test. Children were classified as low, middle and high fitness according to level achieved on the test using reference curves. Physical activity was measured by accelerometry over 7 days. In addition to total activity, time in sedentary behaviour and light, moderate, vigorous, and sustained moderate-to-vigorous activity (âĽ10 min bouts) were calculated. Results - Multiple regression analyses revealed that vigorous activity (β = 0.339, p<0.01), sustained moderate-to-vigorous activity (β = 0.250, p<0.05) and total activity (β = 0.238, p<0.05) were associated with level achieved on the shuttle run test after adjustment for age, sex and GMFCS level. Children with high fitness spent more time in vigorous activity than children with middle fitness (p<0.05). Shuttle run test level was negatively associated with BMI (r2 = -0.451, p<0.01), waist circumference (r2 = -0.560, p<0.001), waist-height ratio (r2 = -0.560, p<0.001) and systolic blood pressure (r2 = -0.306, p<0.05) after adjustment for age, sex and GMFCS level. Conclusions - Participation in physical activity, particularly at a vigorous intensity, is associated with high cardiorespiratory fitness in children with CP. Low cardiorespiratory fitness is associated with increased cardiometabolic risk
How We Know It Hurts: Item Analysis of Written Narratives Reveals Distinct Neural Responses to Others' Physical Pain and Emotional Suffering
People are often called upon to witness, and to empathize with, the pain and suffering of others. In the current study, we directly compared neural responses to others' physical pain and emotional suffering by presenting participants (n = 41) with 96 verbal stories, each describing a protagonist's physical and/or emotional experience, ranging from neutral to extremely negative. A separate group of participants rated âhow much physical painâ, and âhow much emotional sufferingâ the protagonist experienced in each story, as well as how âvivid and movie-likeâ the story was. Although ratings of Pain, Suffering and Vividness were positively correlated with each other across stories, item-analyses revealed that each scale was correlated with activity in distinct brain regions. Even within regions of the âShared Pain networkâ identified using a separate data set, responses to others' physical pain and emotional suffering were distinct. More broadly, item analyses with continuous predictors provided a high-powered method for identifying brain regions associated with specific aspects of complex stimuli â like verbal descriptions of physical and emotional events.United States. Air Force Office of Scientific Research (Office of Naval Research, grant number N000140910845
Genetic defects are common in myopathies with tubular aggregates
Objective: A group of genes have been reported to be associated with myopathies with tubular aggregates (TAs). Many cases with TAs still lack of genetic
clarification. This study aims to explore the genetic background of cases with
TAs in order to improve our knowledge of the pathogenesis of these rare
pathological structures. Methods: Thirty-three patients including two family
members with biopsy confirmed TAs were collected. Whole-exome sequencing
was performed on 31 unrelated index patients and a candidate gene search
strategy was conducted. The identified variants were confirmed by Sanger
sequencing. The wild-type and the mutant p.Ala11Thr of ALG14 were transfected into human embryonic kidney 293 cells (HEK293), and western blot
analysis was performed to quantify protein expression levels. Results: Eleven
index cases (33%) were found to have pathogenic variant or likely pathogenic
variants in STIM1, ORAI1, PGAM2, SCN4A, CASQ1 and ALG14. Among them,
the c.764A>T (p.Glu255Val) in STIM1 and the c.1333G>C (p.Val445Leu) in
SCN4A were novel. Western blot analysis showed that the expression of ALG14
protein was severely reduced in the mutant ALG14 HEK293 cells (p.Ala11Thr)
compared with wild type. The ALG14 variants might be associated with TAs in
patients with complex multisystem disorders. Interpretation: This study
expands the phenotypic and genotypic spectrums of myopathies with TAs. Our
findings further confirm previous hypothesis that genes related with calcium
signalling pathway and N-linked glycosylation pathway are the main genetic
causes of myopathies with TAs
D-Branes on the Conifold and N=1 Gauge/Gravity Dualities
We review extensions of the AdS/CFT correspondence to gauge/ gravity
dualities with N=1 supersymmetry. In particular, we describe the gauge/gravity
dualities that emerge from placing D3-branes at the apex of the conifold. We
consider first the conformal case, with discussions of chiral primary operators
and wrapped D-branes. Next, we break the conformal symmetry by adding a stack
of partially wrapped D5-branes to the system, changing the gauge group and
introducing a logarithmic renormalization group flow. In the gravity dual, the
effect of these wrapped D5-branes is to turn on the flux of 3-form field
strengths. The associated RR 2-form potential breaks the U(1) R-symmetry to
and we study this phenomenon in detail. This extra flux also leads to
deformation of the cone near the apex, which describes the chiral symmetry
breaking and confinement in the dual gauge theory.Comment: Based on I.R.K.'s lectures at the Les Houches Summer School Session
76, ``Gravity, Gauge Theories, and Strings'', August 2001, 42 pages, v2:
clarifications and references adde
Parasite Lost: Chemical and Visual Cues Used by Pseudacteon in Search of Azteca instabilis
An undescribed species of phorid fly (genus: Pseudacteon) parasitizes the ant Azteca instabilis F Smith, by first locating these ants through the use of both chemical and visual cues. Experiments were performed in Chiapas, Mexico to examine a) the anatomical source of phorid attractants, b) the specific chemicals produced that attract phorids, and c) the nature of the visual cues used by phorids to locate the ants. We determined that phorid-attracting chemicals were present within the dorsal section of the abdomen, the location of the pygidial gland. Further experiments indicate that a pygidial gland compound, 1-acetyl-2-methylcyclopentane, is at least partially responsible for attracting phorid flies to their host. Finally, although visual cues such as movement were important for host location, size and color of objects did not influence the frequency with which phorids attacked moving targets
Airflow limitation or static hyperinflation: which is more closely related to dyspnea with activities of daily living in patients with COPD?
<p>Abstract</p> <p>Background</p> <p>Dyspnea while performing the activities of daily living has been suggested to be a better measurement than peak dyspnea during exercise. Furthermore, the inspiratory capacity (IC) has been shown to be more closely related to exercise tolerance and dyspnea than the FEV<sub>1</sub>, because dynamic hyperinflation is the main cause of shortness of breath in patients with COPD. However, breathlessness during exercise is measured in most studies to evaluate this relationship.</p> <p>Purpose</p> <p>To evaluate the correlation between breathlessness during daily activities and airflow limitation or static hyperinflation in COPD.</p> <p>Methods</p> <p>We examined 167 consecutive outpatients with stable COPD. The Baseline Dyspnea Index (BDI) was used to evaluate dyspnea with activities of daily living. The relationship between the BDI score and the clinical measurements of pulmonary function was then investigated.</p> <p>Results</p> <p>The Spearman rank correlation coefficients (Rs) between the BDI score and the FEV<sub>1</sub>(L), FEV<sub>1</sub>(%pred) and FEV<sub>1</sub>/FVC were 0.60, 0.56 and 0.56, respectively. On the other hand, the BDI score also correlated with the IC, IC/predicted total lung capacity (TLC) and IC/TLC (Rs = 0.45, 0.46 and 0.47, respectively). Although all of the relationships studied were strongly correlated, the correlation coefficients were better between dyspnea and airflow limitation than between dyspnea and static hyperinflation. In stepwise multiple regression analyses, the BDI score was most significantly explained by the FEV<sub>1 </sub>(R<sup>2 </sup>= 26.2%) and the diffusion capacity for carbon monoxide (R<sup>2 </sup>= 14.4%) (Cumulative R<sup>2 </sup>= 40.6%). Static hyperinflation was not a significant factor for clinical dyspnea on the stepwise multiple regression analysis.</p> <p>Conclusion</p> <p>Both static hyperinflation and airflow limitation contributed greatly to dyspnea in COPD patients.</p
- âŚ