No confinement without Coulomb confinement

We compare the physical potential $V_D(R)$ of an external quark-antiquark pair in the representation $D$ of SU(N), to the color-Coulomb potential $V_{\rm coul}(R)$ which is the instantaneous part of the 44-component of the gluon propagator in Coulomb gauge, D_{44}(\vx,t) = V_{\rm coul}(|\vx|) \delta(t) + (non-instantaneous). We show that if $V_D(R)$ is confining, $\lim_{R \to \infty}V_D(R) = + \infty$, then the inequality $V_D(R) \leq - C_D V_{\rm coul}(R)$ holds asymptotically at large $R$, where $C_D > 0$ is the Casimir in the representation $D$. This implies that $- V_{\rm coul}(R)$ is also confining.Comment: 9 page

Lenz-Majewski mutations in PTDSS1 affect phosphatidylinositol 4-phosphate metabolism at ER-PM and ER-golgi junctions

Lenz-Majewski syndrome (LMS) is a rare disease characterized by complex craniofacial, dental, cutaneous, and limb abnormalities combined with intellectual disability. Mutations in the PTDSS1 gene coding one of the phosphatidylserine (PS) synthase enzymes, PSS1, were described as causative in LMS patients. Such mutations render PSS1 insensitive to feedback inhibition by PS levels. Here we show that expression of mutant PSS1 enzymes decreased phosphatidylinositol 4-phosphate (PI4P) levels both in the Golgi and the plasma membrane (PM) by activating the Sac1 phosphatase and altered PI4P cycling at the PM. Conversely, inhibitors of PI4KA, the enzyme that makes PI4P in the PM, blocked PS synthesis and reduced PS levels by 50% in normal cells. However, mutant PSS1 enzymes alleviated the PI4P dependence of PS synthesis. Oxysterol-binding protein-related protein 8, which was recently identified as a PI4P-PS exchanger between the ER and PM, showed PI4P-dependent membrane association that was significantly decreased by expression of PSS1 mutant enzymes. Our studies reveal that PS synthesis is tightly coupled to PI4P-dependent PS transport from the ER. Consequently, PSS1 mutations not only affect cellular PS levels and distribution but also lead to a more complex imbalance in lipid homeostasis by disturbing PI4P metabolism

A New Estimate of ε′/ε\varepsilon '/\varepsilon

We discuss direct $CP$ violation in the standard model by giving a new estimate of $\varepsilon'/\varepsilon$ in kaon decays. Our analysis is based on the evaluation of the hadronic matrix elements of the \mbox{$\Delta S =1$} effective quark lagrangian by means of the chiral quark model, with the inclusion of meson one-loop renormalization and NLO Wilson coefficients. Our estimate is fully consistent with the $\Delta I =1/2$ selection rule in $K\to \pi\pi$ decays which is well reproduced within the same framework. By varying all parameters in the allowed ranges and, in particular, taking the quark condensate---which is the major source of uncertainty---between $(-200\ {\rm MeV})^3$ and $(-280\ {\rm MeV})^3$ we find $$-5.0 \times 10^{-3}\ <\varepsilon'/\varepsilon <\ 1.4 \times 10^{-3}\ .$$ Assuming for the quark condensate the improved PCAC result \mbox{\vev{\bar qq} = -(221\: \pm 17\ {\rm MeV})^3} and fixing $\Lambda_{\rm QCD}^{(4)}$ to its central value, we find the more restrictive prediction $$\varepsilon '/\varepsilon = ( 4 \pm 5 ) \,\times \,10^{-4}\ ,$$ where the central value is defined as the average over the allowed values of Im $\lambda_t$ in the first and second quadrants. In these estimates the relevant mixing parameter Im $\lambda_t$ is self-consistently obtained from $\varepsilon$ and we take $m_t^{\rm pole} = 180 \pm 12$ GeV. Our result is, to a very good approximation, renormalization-scale and $\gamma_5$-scheme independent.Comment: 40 pages, uuencoded LATEX2e file including 13 eps figures, revised version to appear in Nucl. Phys.

BRST Inner Product Spaces and the Gribov Obstruction

A global extension of the Batalin-Marnelius proposal for a BRST inner product to gauge theories with topologically nontrivial gauge orbits is discussed. It is shown that their (appropriately adapted) method is applicable to a large class of mechanical models with a semisimple gauge group in the adjoint and fundamental representation. This includes cases where the Faddeev-Popov method fails. Simple models are found also, however, which do not allow for a well-defined global extension of the Batalin-Marnelius inner product due to a Gribov obstruction. Reasons for the partial success and failure are worked out and possible ways to circumvent the problem are briefly discussed.Comment: 49 pages, 1 figure (included

The ΔS=1\Delta S = 1 Weak Chiral Lagrangian as the Effective Theory of the Chiral Quark Model

We use the chiral quark model to estimate the coefficients of the weak chiral lagrangian as obtained from the bosonization of the ten relevant operators of the $\Delta S = 1$ effective quark lagrangian. All contributions of order $N_c^2$ as well as $N_c$ and $\alpha_s N_c$ are included. The chiral coefficients are given in terms of $f_{\pi}$, the quark and gluon condensates and the scale-dependent NLO Wilson coefficients of the corresponding operators. In addition, they depend on the constituent quark mass $M$, a parameter characteristic of the model. The $\gamma_5$-scheme dependence of the chiral coefficients, computed via dimensional regularization, and the Fierz transformation properties of the operator basis are discussed in detail. We apply our result to the evaluation of the hadronic matrix elements for the decay $K^0 \rightarrow 2 \pi$, consistently including the renormalization induced by the meson loops. The effect of this renormalization is sizable and introduces a long-distance scale dependence that matches in the physical amplitudes the short-distance scale dependence of the Wilson coefficients.Comment: Revised version to appear in Nucl. Phys. B 48 pages, uuencoded LATEX file including 4 eps figure

Synoptic studies of seventeen blazars detected in very high-energy gamma-rays

Since 2002, the number of detected blazars at gamma-ray energies above 100 GeV has more than doubled. I study 17 blazars currently known to emit E>100 GeV gamma rays. Their intrinsic energy spectra are reconstructed by removing extragalactic background light attenuation effects. Luminosity and spectral slope in the E>100 GeV region are then compared and correlated among each other, with X-ray, optical and radio data, and with the estimated black hole (BH) masses of the respective host galaxies. According to expectations from synchrotron self-Compton emission models, a correlation on the 3.6-sigma significance level between gamma-ray and X-ray fluxes is found, while correlations between gamma-ray and optical/radio fluxes are less pronounced. Further, a general hardening of the E>100 GeV spectra with increasing gamma-ray luminosity is observed. This goes in line with a correlation of the gamma-ray luminosity and the synchrotron peak frequency, which is also seen. Tests for possible selection effects reveal a hardening of the spectra with increasing redshift. The gamma-ray emission might depend on the mass of the central BH. The studied blazars show no correlation of the BH masses with the spectral index and the luminosity in the E>100 GeV region. Also temporal properties of the X-ray and E>100 GeV gamma-ray flux are considered. No general trends are found, except that the blazars with the most massive BHs do not show particularly high duty cycles. In general, VHE flare time-scales are not found to scale with the BH mass. As a specific application of the luminosity study, a constraint for the still undetermined redshift of the blazar PG 1553+113 is discussed.Comment: 17 pages, 18 figures, MNRAS in press. Abstract extended; minor modifications in sect. 3, 5.5; Fig. 7c corrected; references update

Traumatic injury clinical trial evaluating tranexamic acid in children (TIC-TOC): study protocol for a pilot randomized controlled trial.

BACKGROUND: Trauma is the leading cause of morbidity and mortality in children in the United States. The antifibrinolytic drug tranexamic acid (TXA) improves survival in adults with traumatic hemorrhage, however, the drug has not been evaluated in a clinical trial in severely injured children. We designed the Traumatic Injury Clinical Trial Evaluating Tranexamic Acid in Children (TIC-TOC) trial to evaluate the feasibility of conducting a confirmatory clinical trial that evaluates the effects of TXA in children with severe trauma and hemorrhagic injuries. METHODS: Children with severe trauma and evidence of hemorrhagic torso or brain injuries will be randomized to one of three arms: (1) TXA dose A (15 mg/kg bolus dose over 20 min, followed by 2 mg/kg/hr infusion over 8 h), (2) TXA dose B (30 mg/kg bolus dose over 20 min, followed by 4 mg/kg/hr infusion over 8 h), or (3) placebo. We will use permuted-block randomization by injury type: hemorrhagic brain injury, hemorrhagic torso injury, and combined hemorrhagic brain and torso injury. The trial will be conducted at four pediatric Level I trauma centers. We will collect the following outcome measures: global functioning as measured by the Pediatric Quality of Life (PedsQL) and Pediatric Glasgow Outcome Scale Extended (GOS-E Peds), working memory (digit span test), total amount of blood products transfused in the initial 48 h, intracranial hemorrhage progression at 24 h, coagulation biomarkers, and adverse events (specifically thromboembolic events and seizures). DISCUSSION: This multicenter trial will provide important preliminary data and assess the feasibility of conducting a confirmatory clinical trial that evaluates the benefits of TXA in children with severe trauma and hemorrhagic injuries to the torso and/or brain. TRIAL REGISTRATION: ClinicalTrials.gov registration number: NCT02840097 . Registered on 14 July 2016

The ΔI=1/2\Delta I = 1/2 Selection Rule

We compute the isospin $I= 0$ and 2 amplitudes for the decay of a kaon into two pions by estimating the relevant hadronic matrix elements in the chiral quark model. The results are parametrized in terms of the quark and gluon condensates and of the constituent quark mass $M$. The latter is a parameter characteristic of the model, that we restrict by matching the results in the two $\gamma_5$-schemes (HV and NDR) of dimensional regularization. We find that, for values of these parameters within the current determinations, the $\Delta I= 1/2$ selection rule is well reproduced by means of the cumulative effects of short-distance NLO Wilson coefficients, penguin diagrams, non-factorizable soft-gluon corrections and meson-loop renormalization.Comment: Revised version to be published in Nuclear Physics

Improving the ability of ED physicians to identify subclinical/electrographic seizures on EEG after a brief training module

Background: Approximately 5% of emergency department (ED) patients with altered mental status (AMS) have non-convulsive seizures (NCS). Patients with NCS should be diagnosed with EEG as soon as possible to initiate antiepileptic treatment. Since ED physicians encounter such patients first in the ED, they should be familiar with general EEG principles as well as the EEG patterns of NCS/NCSE. We evaluated the utility of a brief training module in enhancing the ED physicians’ ability to identify seizures on EEG. Methods: This was a randomized controlled trial conducted in three academic institutions. A slide presentation was developed describing the basic principles of EEG including EEG recording techniques, followed by characteristics of normal and abnormal patterns, the goal of which was to familiarize the participants with EEG seizure patterns. We enrolled board-certified emergency medicine physicians into the trial. Subjects were randomized to control or intervention groups. Participants allocated to the intervention group received a self-learning training module and were asked to take a quiz of EEG snapshots after reviewing the presentation, while the control group took the quiz without the training. Results: A total of 30 emergency physicians were enrolled (10 per site, with 15 controls and 15 interventions). Participants were 52% male with median years of practice of 9.5 years (3, 14). The percentage of correct answers in the intervention group (65%, 63% and 75%) was significantly different (p = 0.002) from that of control group (50%, 45% and 60%). Conclusions: A brief self-learning training module improved the ability of emergency physicians in identifying EEG seizure patterns