768 research outputs found
Vacuum Stability as a Guide for Model Building
We explain why vector-like fermions are natural candidates to lift the
Standard Model vacuum instability. Results are further discussed from the
viewpoint of criticality. Several models allow for vector-like quarks and
leptons in the TeV-range which can be searched for at the LHC.Comment: Proceedings Moriond EW 2023, 6 pages, 5 figure
Portals into Higgs Stability
We address the notorious metastability of the standard model (SM) and promote
it to a model building task: What are the new ingredients required to stabilize
the SM up to the Planck scale without encountering subplanckian Landau poles?
Using the SM extended by vector-like fermions, we chart out the corresponding
landscape of Higgs stability. We find that the gauge portal mechanism,
triggered by new SM charge carriers, opens up sizeable room for stability in a
minimally invasive manner. We also find models with Higgs criticality, and
Yukawa portals opening up at stronger coupling. Several models allow for
vector-like fermions in the TeV-range, which can be searched for at the LHC.
For nontrivial flavor structure severe FCNC constraints arise which complement
those from stability, and push lower fermion masses up to
.Comment: 18 pages, 16 figure
Improving Co-benefits and 'Triple Win' Impacts from Climate Action: The Role of Guidance Tools
This CDI Practice Paper by L.O. Naess, M. Hagemann, B. Harvey, F. Urban, S. Hendel-Blackford and N. Höhne addresses the role of tools in supporting interventions to achieve the ‘triple wins’ of adaptation, mitigation and development. Over recent years there has been a proliferation of guidance tools to support adaptation or mitigation, increasingly in a development context, but little work on the role tools play in helping to bridge the gap between these three areas in practice. Based on a review of tools in view of ‘climate compatible development’, the paper suggests key considerations for how tools could help achieve ‘triple wins’. They include (1) the importance of understanding how tools are a way of defining and shaping a goal, not merely helping to implement actions to achieve it; (2) the value of acknowledging different starting points, and that a lot of the integration is happening – and will continue to happen – on the side of users; and (3) because tools cannot provide all the answers to complex problems they need to be complemented by analysis of actors, goals and outcomes.UK Department for International Developmen
Two is better than one: The U-spin-CP anomaly in charm
The recent measurement of the CP-asymmetry in the decay by
LHCb, combined with , evidences a sizable CP-asymmetry in
the decay , which requires a dynamical enhancement of
standard model higher-order contributions over tree-level ones by a factor of
two. The data furthermore imply huge U-spin breaking, about 4-5 times larger
than the nominal standard model one of in charm. Enhanced
breakdown of the two approximate symmetries points to models that violate
U-spin and CP and disfavors flavor singlet contributions such as chromomagnetic
dipole operators as explanations of the data. We analyze the reach of flavorful
models for charm CP-asymmetries. Models generically feature explicit
U-spin and isospin breaking, allowing for correlations with
and decays with corresponding CP-asymmetries at similar
level and sign as , about .
Experimental and theoretical constraints very much narrow down the shape of
viable models: Viable, anomaly-free models are leptophobic, -- or at least
electron- and muon-phobic -- with light below GeV,
and can be searched for in low mass dijets at the LHC or in and
charmonium decays, as well as dark photon searches. Models can also feature
sizable branching ratios into light right-handed neutrinos or vector-like dark
fermions, which can be searched for in at Belle II and BESIII. Due to the low new physics scale dark
fermions can easily induce an early Landau pole, requiring models to be
UV-completed near the TeV-scale.Comment: 13 pages, 5 figures. v2: Fig.1 and discussion on U-Spin improved,
minor corrections and references adde
Old and new anomalies in charm
The recent LHCb determination of the direct CP asymmetries in the decays hints at a sizeable breaking of two approximate
symmetries of the SM: CP and U-spin. We aim at explaining the data with BSM
physics and use the framework of flavorful models. Interestingly,
experimental and theoretical constraints very much narrow down the shape of
viable models: Viable, anomaly-free models are electron- and muon-phobic and
feature a light of 10-20 GeV coupling only to right-handed fermions.
The can be searched for in low mass dijets or at the LHC as well as
dark photon searches. A light of 3 GeV or 5-7 GeV can
moreover resolve the longstanding discrepancy in the
branching ratios with pion form factors from fits to
data, and simultaneously explain the charm CP asymmetries. Smoking gun
signatures for this scenario are and charmonium decays into pions,
taus or invisbles.Comment: 2 pages, 4 figure
SPoC: A novel framework for relating the amplitude of neuronal oscillations to behaviorally relevant parameters
Previously, modulations in power of neuronal oscillations have been functionally linked to sensory, motor and cognitive operations. Such links are commonly established by relating the power modulations to specific target variables such as reaction times or task ratings. Consequently, the resulting spatio-spectral representation is subjected to neurophysiological interpretation. As an alternative, independent component analysis (ICA) or alternative decomposition methods can be applied and the power of the components may be related to the target variable. In this paper we show that these standard approaches are suboptimal as the first does not take into account the superposition of many sources due to volume conduction, while the second is unable to exploit available information about the target variable. To improve upon these approaches we introduce a novel (supervised) source separation framework called Source Power Comodulation (SPoC). SPoC makes use of the target variable in the decomposition process in order to give preference to components whose power comodulates with the target variable. We present two algorithms that implement the SPoC approach. Using simulations with a realistic head model, we show that the SPoC algorithms are able extract neuronal components exhibiting high correlation of power with the target variable. In this task, the SPoC algorithms outperform other commonly used techniques that are based on the sensor data or ICA approaches. Furthermore, using real electroencephalography (EEG) recordings during an auditory steady state paradigm, we demonstrate the utility of the SPoC algorithms by extracting neuronal components exhibiting high correlation of power with the intensity of the auditory input. Taking into account the results of the simulations and real EEG recordings, we conclude that SPoC represents an adequate approach for the optimal extraction of neuronal components showing coupling of power with continuously changing behaviorally relevant parameters
FKBP5 Genotype-Dependent DNA Methylation and mRNA Regulation After Psychosocial Stress in Remitted Depression and Healthy Controls.
BACKGROUND: Polymorphisms in the FK506 binding protein 5 (FKBP5) gene have been shown to influence glucocorticoid receptor sensitivity, stress response regulation, and depression risk in traumatized subjects, with most consistent findings reported for the functional variant rs1360780. In the present study, we investigated whether the FKBP5 polymorphism rs1360780 and lifetime history of major depression are associated with DNA methylation and FKBP5 gene expression after psychosocial stress. METHODS: A total of 116 individuals with a positive (n = 61) and negative (n = 55) lifetime history of major depression participated in the Trier Social Stress Test. We assessed plasma cortisol concentrations, FKBP5 mRNA expression, and CpG methylation of FKBP5 intron 7 in peripheral blood cells. RESULTS: Genotype-dependent plasma cortisol response to psychosocial stress exposure was observed in healthy controls, with the highest and longest-lasting cortisol increase in subjects with the TT genotype of the FKBP5 polymorphism rs1360780, and healthy controls carrying the T risk allele responded with a blunted FKBP5 mRNA expression after psychosocial stress. No genotype effects could be found in remitted depression. CONCLUSIONS: The FKBP5 rs1360780 polymorphism is associated with plasma cortisol and FKBP5 mRNA expression after psychosocial stress in healthy controls but not in remitted depression. Preliminary results of the DNA methylation analysis suggest that epigenetic modifications could be involved
System-size dependence
The final state in The final state in heavy-ion collisions has a higher
degree of strangeness saturation than the one produced in collisions between
elementary particles like p-p or p-. A systematic analysis of this
phenomenon is made for C-C, Si-Si and Pb-Pb collisions at the CERN SPS collider
and for collisions at RHIC and at AGS energies. Strangeness saturation
is shown to increase smoothly with the number of participants at AGS, CERN and
RHIC energies.Comment: 5 pages, 5 figures, presented at SQM2003 conferenc
Prevention of M2 polarization and temporal limitation of differentiation in monocytes by extracellular ATP
BACKGROUND
Elevated levels of extracellular adenosine triphosphate (ATP) modulate immunologic pathways and are considered to be a danger signal in inflammation, lung fibrosis and cancer. Macrophages can be classified into two main types: M1 macrophages are classically activated, pro-inflammatory macrophages, whereas M2 macrophages are alternatively activated, pro-fibrotic macrophages. In this study, we examined the effect of ATP on differentiation of native human monocytes into these macrophage subtypes. We characterized M1 and M2 like macrophages by their release of Interleukin-1beta (IL-1β) and Chemokine (C-C motif) ligand 18 (CCL18), respectively.
RESULTS
Monocytes were stimulated with ATP or the P2X7 receptor agonist Benzoylbenzoyl-ATP (Bz-ATP), and the production of various cytokines was analyzed, with a particular focus on CCL18 and IL-1β, along with the expression of different purinergic receptors. Over a 72 h period of cell culture, monocytes spontaneously differentiated to M2 like macrophages, as indicated by an increased release of CCL18. Immediate stimulation of monocytes with ATP resulted in a dose-dependent reduction in CCL18 release, but had no effect on the concentration of IL-1β. In contrast, delayed stimulation with ATP had no effect on either CCL18 or IL-1β release. Similar results were observed in a model of inflammation using lipopolysaccharide-stimulated human monocytes. Stimulation with the P2X7 receptor agonist Bz-ATP mimicked the effect of ATP on M2-macrophage differentiation, indicating that P2X7 is involved in ATP-induced inhibition of CCL18 release. Indeed, P2X7 was downregulated during spontaneous M2 differentiation, which may partially explain the ineffectiveness of late ATP stimulation of monocytes. However, pre-incubation of monocytes with PPADS, Suramin (unselective P2X- and P2Y-receptor blockers) and KN62 (P2X7-antagonist) failed to reverse the reduction of CCL18 by ATP.
CONCLUSIONS
ATP prevents spontaneous differentiation of monocytes into M2-like macrophages in a dose- and time-dependent manner. These effects were not mediated by P2X and P2Y receptors
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