294 research outputs found
Spinning Sum Rules for the Dimension-Six SMEFT
We construct new dispersive sum rules for the effective field theory of the
standard model at mass dimension six. These spinning sum rules encode
information about the spin of UV states: the sign of the IR Wilson coefficients
carries a memory of the dominant spin in the UV completion. The sum rules are
constructed for operators containing scalars and fermions, although we consider
the dimension-six SMEFT exhaustively, outlining why equivalent relations do not
hold for the remaining operators. As with any dimension-six dispersive
argument, our conclusions are contingent on the absence of potential poles at
infinity, so-called boundary terms, and we discuss in detail where these are
expected to appear. There are a number of phenomenological applications of
spinning sum rules, and as an example we explore the connection to the
Peskin-Takeuchi parameters and, more generally, the set of oblique parameters
in universal theories.Comment: 51 pages, 1 figur
What the Milky Way's Dwarfs tell us about the Galactic Center extended excess
The Milky Way's Galactic Center harbors a gamma-ray excess that is a
candidate signal of annihilating dark matter. Dwarf galaxies remain
predominantly dark in their expected commensurate emission. In this work we
quantify the degree of consistency between these two observations through a
joint likelihood analysis. In doing so we incorporate Milky Way dark matter
halo profile uncertainties, as well as an accounting of diffuse gamma-ray
emission uncertainties in dark matter annihilation models for the Galactic
Center Extended gamma-ray excess (GCE) detected by the Fermi Gamma-Ray Space
Telescope. The preferred range of annihilation rates and masses expands when
including these unknowns. Even so, using two recent determinations of the Milky
Way halo's local density leave the GCE preferred region of single-channel dark
matter annihilation models to be in strong tension with annihilation searches
in combined dwarf galaxy analyses. A third, higher Milky Way density
determination, alleviates this tension. Our joint likelihood analysis allows us
to quantify this inconsistency. We provide a set of tools for testing dark
matter annihilation models' consistency within this combined dataset. As an
example, we test a representative inverse Compton sourced self-interacting dark
matter model, which is consistent with both the GCE and dwarfs.Comment: v2, 12 pages, 4 figures, tools online at:
https://github.com/rekeeley/GCE_error
Molar incisor hypomineralisation: current knowledge and practice
Background
Molar incisor hypomineralisation (MIH) is a common developmental dental condition that presents in childhood. Areas of poorly formed enamel affect one or more first permanent molars and can cause opacities on the anterior teeth. MIH presents a variety of challenges for the dental team as well as functional and social impacts for affected children.
Objectives
Here, we provide an up‐to‐date review of the epidemiology, aetiology, diagnosis and clinical management of MIH.
Materials and methods
A review of the contemporary basic science and clinical literature, relating to MIH, was undertaken using information obtained (up to 10 April 2020) from the electronic databases PubMed, Scopus, Web of Science and the Cochrane Library.
Results
There is a growing body of evidence relating to the aetiology, presentation and clinical management of MIH. Current knowledge appears to be focused on potential genetic aspects, as well as the development and validation of indices for the diagnosis and management of MIH. There has also been increasing recognition of the global and individual burden of this common condition.
Conclusions
Dental health professionals should regularly appraise the basic science and clinical MIH literature to ensure that they provide the best possible short‐ and long‐term care for their young patients
Multifield Positivity Bounds for Inflation
Positivity bounds represent nontrivial limitations on effective field
theories (EFTs) if those EFTs are to be completed into a Lorentz-invariant,
causal, local, and unitary framework. While such positivity bounds have been
applied in a wide array of physical contexts to obtain useful constraints,
their application to inflationary EFTs is subtle since Lorentz invariance is
spontaneously broken during cosmic inflation. One path forward is to employ a
to ensure a crossing-symmetric and analytic
S-matrix in theories with broken boosts. We extend this approach to a theory
with multiple fields, and uncover a fundamental obstruction that arises unless
all fields obey a dispersion relation that is approximately lightlike. We then
apply the formalism to various classes of inflationary EFTs, with and without
isocurvature perturbations, and employ this parameterization to derive new
positivity bounds on such EFTs. For multifield inflation, we also consider
bounds originating from the generalized optical theorem and demonstrate how
these can give rise to stronger constraints on EFTs compared to constraints
from traditional elastic positivity bounds alone. We compute various shapes of
non-Gaussianity (NG), involving both adiabatic and isocurvature perturbations,
and show how the observational parameter space controlling the strength of NG
can be constrained by our bounds.Comment: 49 pages, 4 figures; v2: clarifications added, journal versio
Differential gene expression in the nucleus accumbens with ethanol self-administration in inbred alcohol-preferring rats
The current study examined the effects of operant ethanol (EtOH) self-administration on gene expression in the nucleus accumbens (ACB) and amygdala (AMYG) of inbred alcohol-preferring (iP) rats. Rats self-trained on a standard two-lever operant paradigm to administer either water-water, EtOH (15% v/v)-water, or saccharin (SAC; 0.0125% g/v)-water. Animals were killed 24 hr after the last operant session, and the ACB and AMYG dissected; RNA was extracted and purified for microarray analysis. For the ACB, there were 513 significant differences at the p < 0.01 level in named genes: 55 between SAC and water; 215 between EtOH and water, and 243 between EtOH and SAC. In the case of the AMYG (p < 0.01), there were 48 between SAC and water, 23 between EtOH and water, and 63 between EtOH and SAC group. Gene Ontology (GO) analysis indicated that differences in the ACB between the EtOH and SAC groups could be grouped into 15 significant (p < 0.05) categories, which included major categories such as synaptic transmission, cell and ion homeostasis, and neurogenesis, whereas differences between the EtOH and water groups had only 4 categories, which also included homeostasis and synaptic transmission. Several genes were in common between the EtOH and both the SAC and water groups in the synaptic transmission (e.g., Cav2, Nrxn, Gabrb2, Gad1, Homer1) and homeostasis (S100b, Prkca, Ftl1) categories. Overall, the results suggest that changes in gene expression in the ACB of iP rats are associated with the reinforcing effects of EtOH
Changes in Gene Expression within the Extended Amygdala following Binge-Like Alcohol Drinking by Adolescent Alcohol-Preferring (P) Rats
The objective of this study was to determine changes in gene expression within the extended amygdala following binge-like alcohol drinking by male adolescent alcohol-preferring (P) rats. Starting at 28 days of age, P rats were given concurrent access to 15 and 30 % ethanol for 3 one-h sessions/day for 5 consecutive days/week for 3 weeks. Rats were killed by decapitation 3 h after the first ethanol access session on the 15th day of drinking. RNA was prepared from micropunch samples of the nucleus accumbens shell (Acb-sh) and central nucleus of the amygdala (CeA). Ethanol intakes were 2.5 – 3.0 g/kg/session. There were 154 and 182 unique named genes that significantly differed (FDR = 0.2) between the water and ethanol group in the Acb-sh and CeA, respectively. Gene Ontology (GO) analyses indicated that adolescent binge drinking produced changes in biological processes involved with cell proliferation and regulation of cellular structure in the Acb-sh, and in neuron projection and positive regulation of cellular organization in the CeA. Ingenuity Pathway Analysis indicated that, in the Acb-sh, there were several major intracellular signaling pathways (e.g., cAMP-mediated and protein kinase A signaling pathways) altered by adolescent drinking, with 3-fold more genes up-regulated than down-regulated in the alcohol group. The cAMP-mediated signaling system was also up-regulated in the CeA of the alcohol group. Weighted gene co-expression network analysis indicated significant G-protein coupled receptor signaling and transmembrane receptor protein kinase signaling categories in the Acb-sh and CeA, respectively. Overall, the results of this study indicated that binge-like alcohol drinking by adolescent P rats is differentially altering the expression of genes in the Acb-sh and CeA, some of which are involved in intracellular signaling pathways and may produce changes in neuronal function
Microfluidic systems for the analysis of the viscoelastic fluid flow phenomena in porous media
In this study, two microfluidic devices are proposed as simplified 1-D microfluidic analogues of a porous medium. The objectives are twofold: firstly to assess the usefulness of the microchannels to mimic the porous medium in a controlled and simplified manner, and secondly to obtain a better insight about the flow characteristics of viscoelastic fluids flowing through a packed bed. For these purposes, flow visualizations and pressure drop measurements are conducted with Newtonian and viscoelastic fluids. The 1-D microfluidic analogues of porous medium consisted of microchannels with a sequence of contractions/ expansions disposed in symmetric and asymmetric arrangements. The real porous medium is in reality, a complex combination of the two arrangements of particles simulated with the microchannels, which can be considered as limiting ideal configurations. The results show that both configurations are able to mimic well the pressure drop variation with flow rate for Newtonian fluids. However, due to the intrinsic differences in the deformation rate profiles associated with each microgeometry, the symmetric configuration is more suitable for studying the flow of viscoelastic fluids at low De values, while the asymmetric configuration provides better results at high De values. In this way, both microgeometries seem to be complementary and could be interesting tools to obtain a better insight about the flow of viscoelastic fluids through a porous medium. Such model systems could be very interesting to use in polymer-flood processes for enhanced oil recovery, for instance, as a tool for selecting the most suitable viscoelastic fluid to be used in a specific formation. The selection of the fluid properties of a detergent for cleaning oil contaminated soil, sand, and in general, any porous material, is another possible application
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