Slow running of the Gradient Flow coupling from 200 MeV to 4 GeV in Nf=3N_{\rm f}=3 QCD

Using a finite volume Gradient Flow (GF) renormalization scheme with Schr\"odinger Functional (SF) boundary conditions, we compute the non-perturbative running coupling in the range $2.2 \lesssim {\bar g}_\mathrm{GF}^2(L) \lesssim 13$. Careful continuum extrapolations turn out to be crucial to reach our high accuracy. The running of the coupling is always between one-loop and two-loop and very close to one-loop in the region of $200\,{\rm MeV} \lesssim \mu=1/L \lesssim 4\,{\rm GeV}$. While there is no convincing contact to two-loop running, we match non-perturbatively to the SF coupling with background field. In this case we know the $\mu$ dependence up to $\sim 100\,{\rm GeV}$ and can thus connect to the $\Lambda$-parameter.Comment: 34 pages, LaTe

A status update on the determination of ΛMS‾Nf=3{\Lambda}_{\overline{\rm MS}}^{N_{\rm f}=3} by the ALPHA collaboration

The ALPHA collaboration aims to determine $\alpha_s(m_Z)$ with a total error below the percent level. A further step towards this goal can be taken by combining results from the recent simulations of 2+1-flavour QCD by the CLS initiative with a number of tools developed over the years: renormalized couplings in finite volume schemes, recursive finite size techniques, two-loop renormalized perturbation theory and the (improved) gradient flow on the lattice. We sketch the strategy, which involves both the standard SF coupling in the high energy regime and a gradient flow coupling at low energies. This implies the need for matching both schemes at an intermediate switching scale, $L_{\rm swi}$, which we choose roughly in the range 2-4 GeV. In this contribution we present a preliminary result for this matching procedure, and we then focus on our almost final results for the scale evolution of the SF coupling from $L_{\rm swi}$ towards the perturbative regime, where we extract the $N_{\rm f} = 3$ ${\Lambda}$-parameter, ${\Lambda}_{\overline{\rm MS}}^{N_{\rm f}=3}$, in units of $L_{\rm swi}$ . Connecting $L_{\rm swi}$ and thus the ${\Lambda}$-parameter to a hadronic scale such as $F_K$ requires 2 further ingredients: first, the connection of $L_{\rm swi}$ to $L_{\rm max}$ using a few steps with the step-scaling function of the gradient flow coupling, and, second, the continuum extrapolation of $L_{\rm max} F_K$.Comment: 7 pages, 4 figures, Proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe, Japa

Anharmonic stabilization and band gap renormalization in the perovskite CsSnI₃

Amongst the X(Sn,Pb)Y$_3$ perovskites currently under scrutiny for their photovoltaic applications, the cubic B-$\alpha$ phase of CsSnI$_3$ is arguably the best characterized experimentally. Yet, according to the standard harmonic theory of phonons, this deceptively simple phase should not exist at all due to rotational instabilities of the SnI$_6$ octahedra. Here, employing self-consistent phonon theory we show that these soft modes are stabilized at experimental conditions through anharmonic phonon-phonon interactions between the Cs ions and their iodine cages. We further calculate the renormalization of the electronic energies due to vibrations and find an unusual opening of the band gap, estimated as 0.24 and 0.11 eV at 500 and 300 K, which we attribute to the stretching of Sn-I bonds. Our work demonstrates the important role of temperature in accurately describing these materials.Comment: 12 pages, 4 figure

Treatment as required versus regular monthly treatment in the management of neovascular age-related macular degeneration: a systematic review and meta-analysis

Background: To investigate whether treatment as required ‘pro re nata’ (PRN) versus regular monthly treatment regimens lead to differences in outcomes in neovascular age-related macular degeneration (nAMD). Regular monthly administration of vascular endothelial growth factor (VEGF) inhibitors is an established gold standard treatment, but this approach is costly. Replacement of monthly by PRN treatment can only be justified if there is no difference in patient relevant outcomes. Methods: Systematic review and meta-analysis. The intervention was PRN treatment and the comparator was monthly treatment with VEGF-inhibitors. Four bibliographic databases were searched for randomised controlled trials comparing both treatment regimens directly (head-to-head studies). The last literature search was conducted in December 2014. Risk of bias assessment was performed after the Cochrane Handbook for Systematic Reviews of Interventions. Findings: We included 3 head-to-head studies (6 reports) involving more than 2000 patients. After 2 years, the weighted mean difference in best corrected visual acuity (BCVA) was 1.9 (95% CI 0.5 to 3.3) ETDRS letters in favour of monthly treatment. Systemic adverse events were higher in PRN treated patients, but these differences were not statistically significant. After 2 years, the total number of intravitreal injections required by the patients in the PRN arms were 8.4 (95% CI 7.9 to 8.9) fewer than those having monthly treatment. The studies were considered to have a moderate risk of bias. Conclusions: PRN treatment resulted in minor but statistically significant decrease in mean BCVA which may not be clinically meaningful. There is a small increase in risk of systemic adverse events for PRN treated patients. Overall, the results indicate that an individualized treatment approach with anti-VEGF using visual acuity and OCT-guided re-treatment criteria may be appropriate for most patients with nAMD

The determination of αs\alpha_s by the ALPHA collaboration

We review the ALPHA collaboration strategy for obtaining the QCD coupling at high scale. In the three-flavor effective theory it avoids the use of perturbation theory at $\alpha > 0.2$ and at the same time has the physical scales small compared to the cutoff $1/a$ in all stages of the computation. The result \Lambda_\overline{MS}^{(3)}=332(14)~MeV is translated to \alpha_\overline{MS}(m_Z)=0.1179(10)(2) by use of (high order) perturbative relations between the effective theory couplings at the charm and beauty quark "thresholds". The error of this perturbative step is discussed and estimated as $0.0002$.Comment: 7 pages, proceedings of FPCapri2016 conferenc

Pristionchus.org: a genome-centric database of the nematode satellite species Pristionchus pacificus

Comparative studies have been of invaluable importance to the understanding of evolutionary biology. The evolution of developmental programs can be studied in nematodes at a single cell resolution given their fixed cell lineage. We have established Pristionchus pacificus as a major satellite organism for evolutionary developmental biology relative to Caenorhabditis elegans, the model nematode. Online genomic information to support studies in this satellite system can be accessed at . Our web resource offers diverse content covering genome browsing, genetic and physical maps, similarity searches, a community platform and assembly details. Content will be continuously improved as we annotate the P.pacificus genome, and will be an indispensable resource for P.pacificus genomics

Youth Single-Sport Specialization in Professional Baseball Players.

Background: An increasing number of youth baseball athletes are specializing in playing baseball at younger ages. Purpose: The purpose of our study was to describe the age and prevalence of single-sport specialization in a cohort of current professional baseball athletes. In addition, we sought to understand the trends surrounding single-sport specialization in professional baseball players raised within and outside the United States (US). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A survey was distributed to male professional baseball athletes via individual team athletic trainers. Athletes were asked if and at what age they had chosen to specialize in playing baseball at the exclusion of other sports, and data were then collected pertaining to this decision. We analyzed the rate and age of specialization, the reasons for specialization, and the athlete\u27s perception of injuries related to specialization. Results: A total of 1673 professional baseball athletes completed the survey, representing 26 of the 30 Major League Baseball (MLB) organizations. Less than half (44.5%) of professional athletes specialized in playing a single sport during their childhood/adolescence. Those who reported specializing in their youth did so at a mean age of 14.09 ± 2.79 years. MLB players who grew up outside the US specialized at a significantly earlier age than MLB players native to the US (12.30 ± 3.07 vs 14.89 ± 2.24 years, respectively; Conclusion: This study challenges the current trends toward early youth sport specialization, finding that the majority of professional baseball athletes studied did not specialize as youth and that those who did specialize did so at a mean age of 14 years. With the potential cumulative effects of pitching and overhead throwing on an athlete\u27s arm, the trend identified in this study toward earlier specialization within baseball is concerning

Structural Diversity of Peptoids: Tube-Like Structures of Macrocycles

Peptoids, or poly-N-substituted glycines, are characterised by broad structural diversity. Compared to peptides, they are less restricted in rotation and lack backbone-derived H bonding. Nevertheless, certain side chains force the peptoid backbone into distinct conformations. Designable secondary structures like helices or nanosheets arise from this knowledge. Herein, we report the copper-catalysed alkyne-azide cycloaddition (CuAAC) of macrocycles to form innovative tube-like tricyclic peptoids, giving access to host–guest chemistry or storage applications. Different linker systems make the single tubes tuneable in size and enable modifications within the gap. An azobenzene linker, which is reversibly switchable in conformation, was successfully incorporated and allowed for light-triggered changes of the entire tricyclic structure

Structural Diversity of Peptoids: Tube-Like Structures of Macrocycles

Peptoids, or poly-N-substituted glycines, are characterised by broad structural diversity. Compared to peptides, they are less restricted in rotation and lack backbone-derived H bonding. Nevertheless, certain side chains force the peptoid backbone into distinct conformations. Designable secondary structures like helices or nanosheets arise from this knowledge. Herein, we report the copper-catalysed alkyne-azide cycloaddition (CuAAC) of macrocycles to form innovative tube-like tricyclic peptoids, giving access to host–guest chemistry or storage applications. Different linker systems make the single tubes tuneable in size and enable modifications within the gap. An azobenzene linker, which is reversibly switchable in conformation, was successfully incorporated and allowed for light-triggered changes of the entire tricyclic structure