Investigating some technical improvements to glueball calculations

7 pages. Talk presented at the lattice 2015 conferenceWe briefly discuss some issues concerning including the pseudoscalar glueball interpolating operators into the variational basis for computing the masses of the eta and etaprime mesons. As a start we present some preliminary results for the correlators from pseudoscalar glueball operators on nf = 2+1+1 twisted mass gauge configurations. Preliminary results for the effect of open boundary conditions on the masses of three glueballs computed in quenched QCD are presented. The statistics of glueball correlators are briefly discussed

The Gravitational and Electrostatic Fields Far from an Isolated Einstein-Maxwell Source

The exterior solution for an arbitrary charged, massive source, is studied as a static deviation from the Reissner-Nordstr\o m metric. This is reduced to two coupled ordinary differential equations for the gravitational and electrostatic potential functions. The homogeneous equations are explicitly solved in the particular case $q^2=m^2$, obtaining a multipole expansion with radial hypergeometric dependence for both potentials. In the limiting case of a neutral source, the equations are shown to coincide with recent results by Bondi and Rindler.Comment: 11 pages, revTe

Conformal vs confining scenario in SU(2) with adjoint fermions

The masses of the lowest-lying states in the meson and in the gluonic sector of an SU(2) gauge theory with two Dirac flavors in the adjoint representation are measured on the lattice at a fixed value of the lattice coupling $\beta = 4/g_0^2 = 2.25$ for values of the bare fermion mass $m_0$ that span a range between the quenched regime and the massless limit, and for various lattice volumes. Even for light constituent fermions the lightest glueballs are found to be lighter than the lightest mesons. Moreover, the string tension between two static fundamental sources strongly depends on the mass of the dynamical fermions and becomes of the order of the inverse squared lattice linear size before the chiral limit is reached. The implications of these findings for the phase of the theory in the massless limit are discussed and a strategy for discriminating between the (near--)conformal and the confining scenario is outlined.Comment: 5 pages, 4 figures using RevTeX4, Typos corrected, references added. Versions to appear on PR

Thyroid ultrasonography reporting: consensus of Italian Thyroid Association (AIT), Italian Society of Endocrinology (SIE), Italian Society of Ultrasonography in Medicine and Biology (SIUMB) and Ultrasound Chapter of Italian Society of Medical Radiology (SIRM)

Thyroid ultrasonography (US) is the gold standard for thyroid imaging and its widespread use is due to an optimal spatial resolution for superficial anatomic structures, a low cost and the lack of health risks. Thyroid US is a pivotal tool for the diagnosis and follow-up of autoimmune thyroid diseases, for assessing nodule size and echostructure and defining the risk of malignancy in thyroid nodules. The main limitation of US is the poor reproducibility, due to the variable experience of the operators and the different performance and settings of the equipments. Aim of this consensus statement is to standardize the report of thyroid US through the definition of common minimum requirements and a correct terminology. US patterns of autoimmune thyroid diseases are defined. US signs of malignancy in thyroid nodules are classified and scored in each nodule. We also propose a simplified nodule risk stratification, based on the predictive value of each US sign, classified and scored according to the strength of association with malignancy, but also to the estimated reproducibility among different operators

Large volumes and spectroscopy of walking theories

A detailed investigation of finite-size effects is performed for SU(2) gauge theory with two fermions in the adjoint representation, which previous lattice studies have shown to be inside the conformal window. The system is investigated with different spatial and temporal boundary conditions on lattices of various spatial and temporal extensions, for two values of the bare fermion mass representing a heavy and light fermion regime. Our study shows that the infinite-volume limit of masses and decay constants in the mesonic sector is reached only when the mass of the pseudoscalar particle MPS and the spatial lattice size L satisfy the relation LMPS≥15. This bound, which is at least a factor of three higher than what is observed in QCD, is a likely consequence of the different spectral signatures of the two theories, with the scalar isosinglet (0++ glueball) being the lightest particle in our model. In addition to stressing the importance of simulating large lattice sizes, our analysis emphasizes the need to understand quantitatively the full spectrum of the theory rather than just the spectrum in the mesonic isotriplet sector. While for the lightest fermion measuring masses from gluonic operators proves to be still challenging, reliable results for glueball states are obtained at the largest fermion mass and, in the mesonic sector, for both fermion masses. As a byproduct of our investigation, we perform a finite-size scaling of the pseudoscalar mass and decay constant. The data presented in this work support the conformal behavior of this theory with an anomalous dimension γ*≃0.37

Evolutionary patterns of morphometrics, allozymes and mitochondrial DNA in thrashers (Genus Toxostoma)

We examined patterns of variation in skeletal morphometrics (29 characters), allozymes (34 loci), mitochondrial DNA (mtDNA) restriction sites (n = 74) and fragments (n = 395), and mtDNA sequences (1,739 bp from cytochrome b, ND2, ND6, and the control region) among all species of Toxostoma. The phenetic pattern of variation in skeletal morphometrics generally matched traditional taxonomic groupings (based on plumage patterns) with the exceptions of T. redivivum, which because of its large size clusters outside of its proper evolutionary group (lecontei), and T. occelatum, which did not cluster with T. curvirostre. Skull characters contributed highly to species discrimination, suggesting that unique feeding adaptations arose in different species groups. Although genetic variation was detected at isozyme loci (average heterozygosity = 3.6%), these data yielded little phylogenetic resolution. Similarly, mtDNA restriction sites were relatively uninformative; hence, phylogenetic conclusions were based on sequence data. Phylogenetic analyses confirmed the monophyly of these traditionally recognized assemblages: rufum group (T. rufum, T. longirostre, and T. guttatum), lecontei group (T. lecontei, T. crissale, and T. redivivum), and cinereum group (T. bendirei and T. cinereum). The cinereum and lecontei groups appear to be sister lineages. Monophyly of the curvirostre group (which also includes T. occelatum) was not confirmed. Sequence data suggest that T. occelatum and T. curvirostre, which differ by 7.7% sequence divergence, are probably most closely related to the rufum group. Toxostoma rufum and T. longirostre have similar external appearances and differ by 5.0%. Toxostoma guttatum is restricted to Cozumel Island and often is considered a subspecies of T. longirostre; it differs by more than 5% from the other two members of the rufum group and is a distinct species constituting the basal member of this group. The phenotypically distinctive T. bendirei and T. cinereum differ in sequence divergence by only 1.6%. Overall, mtDNA distances computed from coding genes (mean 8.5%) exceeded distances computed from the control region (mean 7.6%), contrary to expectation. Because neither allozymes nor mtDNA could unambiguously resolve the placement of T. occelatum and T. curvirostre, a scenario involving contemporaneous speciation is suggested. Application of a molecular clock suggested that most speciation occurred in the late Pliocene or early Pleistocene

Measurement errors in body size of sea scallops (Placopecten magellanicus) and their effect on stock assessment models

Body-size measurement errors are usually ignored in stock assessments, but may be important when body-size data (e.g., from visual sur veys) are imprecise. We used experiments and models to quantify measurement errors and their effects on assessment models for sea scallops (Placopecten magellanicus). Errors in size data obscured modes from strong year classes and increased frequency and size of the largest and smallest sizes, potentially biasing growth, mortality, and biomass estimates. Modeling techniques for errors in age data proved useful for errors in size data. In terms of a goodness of model fit to the assessment data, it was more important to accommodate variance than bias. Models that accommodated size errors fitted size data substantially better. We recommend experimental quantification of errors along with a modeling approach that accommodates measurement errors because a direct algebraic approach was not robust and because error parameters were diff icult to estimate in our assessment model. The importance of measurement errors depends on many factors and should be evaluated on a case by case basis

Robust Bayes-Like Estimation: Rho-Bayes estimation

We consider the problem of estimating the joint distribution $P$ of $n$ independent random variables within the Bayes paradigm from a non-asymptotic point of view. Assuming that $P$ admits some density $s$ with respect to a given reference measure, we consider a density model $\overline S$ for $s$ that we endow with a prior distribution $\pi$ (with support $\overline S$) and we build a robust alternative to the classical Bayes posterior distribution which possesses similar concentration properties around $s$ whenever it belongs to the model $\overline S$. Furthermore, in density estimation, the Hellinger distance between the classical and the robust posterior distributions tends to 0, as the number of observations tends to infinity, under suitable assumptions on the model and the prior, provided that the model $\overline S$ contains the true density $s$. However, unlike what happens with the classical Bayes posterior distribution, we show that the concentration properties of this new posterior distribution are still preserved in the case of a misspecification of the model, that is when $s$ does not belong to $\overline S$ but is close enough to it with respect to the Hellinger distance.Comment: 68 page

BSMBench: A flexible and scalable HPC benchmark from beyond the standard model physics

Lattice Quantum ChromoDynamics (QCD), and by extension its parent field, Lattice Gauge Theory (LGT), make up a significant fraction of supercomputing cycles worldwide. As such, it would be irresponsible not to evaluate machines’ suitability for such applications. To this end, a benchmark has been developed to assess the performance of LGT applications on modern HPC platforms. Distinct from previous QCD-based benchmarks, this allows probing the behaviour of a variety of theories, which allows varying the ratio of demands between on- node computations and inter-node communications. The results of testing this benchmark on various recent HPC platforms are presented, and directions for future development are discussed