56 research outputs found
Static SU(3) potentials for sources in various representations
The potentials and string tensions between static sources in a variety of
representations (fundamental, 8, 6, 15-antisymmetric, 10, 27 and 15-symmetric)
have been computed by measuring Wilson loops in pure gauge SU(3). The
simulations have been done primarily on anisotropic lattices, using a tadpole
improved action improved to O(a_{s}^4). A range of lattice spacings (0.43 fm,
0.25 fm and 0.11 fm) and volumes (, , and ) has been used in an attempt to control
discretization and finite volume effects. At intermediate distances, the
results show approximate Casimir scaling. Finite lattice spacing effects
dominate systematic error, and are particularly large for the representations
with the largest string tensions.Comment: Version to appear in PR
ANALYSIS OF A TWO LACTATION TARGET ANIMAL SAFETY STUDY OF SOMIDOBOVE SUSTAINED RELEASE INJECTION IN MULTIPAROUS DAIRY COWS
An overview is given of the primary basis for the scientific inference that somidobove sustained release injection is safe for multiparous dairy cows. The process of analysis and interpretation of the voluminous data collected from a target animal safety study which started with 28 cows and lasted two lactations is described. This was a repeated measures study with most of 60 variables being measured or summarized every 28 days resulting in approximately 1500 measurements per cow. The statistical analysis was designed to screen the variables for biological change caused by treatment and consisted of a univariate analysis of variance for repeated measures data both within a lactation and across two lactations. Graphs of least squares means with error bounds and p-value plots of ANOVA p-values helped communicate statistical findings. A cross disciplinary approach interpreted analyses and arrived at inferences
Vacuum replicas in QCD
The properties of the vacuum are addressed in the two- and four-dimensional
quark models for QCD. It is demonstrated that the two-dimensional QCD ('t Hooft
model) possesses only one possible vacuum state - the solution to the mass-gap
equation, which provides spontaneous breaking of the chiral symmetry (SBCS). On
the contrary, the four-dimensional theory with confinement modeled by the
linear potential supplied by the Coulomb OGE interaction, not only has the
chirally-noninvariant ground vacuum state, but it possesses an excited vacuum
replica, which also exhibits SBCS and can realize as a metastable intermediate
state of hadronic systems. We discuss the influence of the latter on physical
observables as well as on the possibility to probe the vacuum background fields
in QCD.Comment: RevTeX4, 26 pages, 8 EPS figures, extended references, corrected some
typos, to appear in Phys.Rev.
k-strings and baryon vertices in SU(N) gauge theories
It is pointed out that the sine law for the k-string tension emerges as the
critical threshold below which the spatial Z_N symmetry of the static baryon
potential is spontaneously broken. This result applies not only to SU(N) gauge
theories, but to any gauge system with stable k-strings admitting a baryon
vertex made with N sources in the fundamental representation. Some simple
examples are worked out.Comment: 4 pages, 4 figures, v2: reference added, v3: comments and references
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Casimir scaling of SU(3) static potentials
Potentials between static colour sources in eight different representations
are computed in four dimensional SU(3) gauge theory. The simulations have been
performed with the Wilson action on anisotropic lattices where the renormalised
anisotropies have been determined non-perturbatively. After an extrapolation to
the continuum limit we are able to exclude any violations of the Casimir
scaling hypothesis that exceed 5% for source separations of up to 1 fm.Comment: 12 pages, 10 figures, RevTeX, v2: 1 reference added, more explanation
about advantages of anisotrop
k-string tensions in SU(N) gauge theories
In the context of four-dimensional SU(N) gauge theories, we study the
spectrum of the confining strings. We compute, for the SU(6) gauge theory
formulated on a lattice, the three independent string tensions sigma_k related
to sources with Z_N charge k=1,2,3, using Monte Carlo simulations. Our results,
whose uncertainty is approximately 2% for k=2 and 4% for k=3, are consistent
with the sine formula sigma_k/sigma = sin(k pi/N) / \sin(pi/N) for the ratio
between sigma_k and the standard string tension sigma, and show deviations from
the Casimir scaling.
The sine formula is known to emerge in supersymmetric SU(N) gauge theories
and in M-theory. We comment on an analogous behavior exhibited by
two-dimensional SU(N)xSU(N) chiral models.Comment: version accepted for publication in Phys Rev D (Rap Comm
Color superconductivity, Z_N flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories
We study the Z_N flux tubes and monopole confinement in deformed N=2* super
Yang-Mills theories. In order to do that we consider an N=4 super Yang-Mills
theory with an arbitrary gauge group G and add some N=2, N=1 and N=0
deformation terms. We analyze some possible vacuum solutions and phases of the
theory, depending on the deformation terms which are added. In the Coulomb
phase for the N=2* theory, G is broken to U(1)^r and the theory has monopole
solutions. Then, by adding some deformation terms, the theory passes to the
Higgs or color superconducting phase, in which G is broken to its center C_G.
In this phase we construct the Z_N flux tubes ansatz and obtain the BPS string
tension. We show that the monopole magnetic fluxes are linear integer
combinations of the string fluxes and therefore the monopoles can become
confined. Then, we obtain a bound for the threshold length of the
string-breaking. We also show the possible formation of a confining system with
3 different monopoles for the SU(3) gauge group. Finally we show that the BPS
string tensions of the theory satisfy the Casimir scaling law.Comment: 18 pages, 2 figures, typo corrections. Version to appear in Phys.
Rev.
Global burden of chronic respiratory diseases and risk factors, 1990–2019: an update from the Global Burden of Disease Study 2019
Background: Updated data on chronic respiratory diseases (CRDs) are vital in their prevention, control, and treatment in the path to achieving the third UN Sustainable Development Goals (SDGs), a one-third reduction in premature mortality from non-communicable diseases by 2030. We provided global, regional, and national estimates of the burden of CRDs and their attributable risks from 1990 to 2019. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated mortality, years lived with disability, years of life lost, disability-adjusted life years (DALYs), prevalence, and incidence of CRDs, i.e. chronic obstructive pulmonary disease (COPD), asthma, pneumoconiosis, interstitial lung disease and pulmonary sarcoidosis, and other CRDs, from 1990 to 2019 by sex, age, region, and Socio-demographic Index (SDI) in 204 countries and territories. Deaths and DALYs from CRDs attributable to each risk factor were estimated according to relative risks, risk exposure, and the theoretical minimum risk exposure level input. Findings: In 2019, CRDs were the third leading cause of death responsible for 4.0 million deaths (95% uncertainty interval 3.6–4.3) with a prevalence of 454.6 million cases (417.4–499.1) globally. While the total deaths and prevalence of CRDs have increased by 28.5% and 39.8%, the age-standardised rates have dropped by 41.7% and 16.9% from 1990 to 2019, respectively. COPD, with 212.3 million (200.4–225.1) prevalent cases, was the primary cause of deaths from CRDs, accounting for 3.3 million (2.9–3.6) deaths. With 262.4 million (224.1–309.5) prevalent cases, asthma had the highest prevalence among CRDs. The age-standardised rates of all burden measures of COPD, asthma, and pneumoconiosis have reduced globally from 1990 to 2019. Nevertheless, the age-standardised rates of incidence and prevalence of interstitial lung disease and pulmonary sarcoidosis have increased throughout this period. Low- and low-middle SDI countries had the highest age-standardised death and DALYs rates while the high SDI quintile had the highest prevalence rate of CRDs. The highest deaths and DALYs from CRDs were attributed to smoking globally, followed by air pollution and occupational risks. Non-optimal temperature and high body-mass index were additional risk factors for COPD and asthma, respectively. Interpretation: Albeit the age-standardised prevalence, death, and DALYs rates of CRDs have decreased, they still cause a substantial burden and deaths worldwide. The high death and DALYs rates in low and low-middle SDI countries highlights the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for tobacco control, enhancing air quality, reducing occupational hazards, and fostering clean cooking fuels are crucial steps in reducing the burden of CRDs, especially in low- and lower-middle income countries
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