1,233 research outputs found
R-symmetry, Yukawa textures and anomaly mediated supersymmetry breaking
We explore, in the MSSM context, an extension of the Anomaly Mediated
Supersymmetry Breaking solution for the soft scalar masses that is possible if
the underlying theory has a gauged R-symmetry. The slepton mass problem
characteristic of the scenario is resolved, and a context for the explanation
of the fermion mass hierarchy provided.Comment: 12 pages, Plain TeX, Uses Harvmac (big). More references added, and
improved discussion of FCNC
Anomaly Mediation, Fayet-Iliopoulos D-terms and precision sparticle spectra
We consider the sparticle spectra that arise when anomaly mediation is the
source of supersymmetry-breaking and the tachyonic slepton problem is solved by
a Fayet-Iliopoulos D-term. We also show how this can lead to a minimal viable
extension of anomaly mediation, in which the gauge symmetry associated with
this D-term is broken at very high energies, leaving as its footprint in the
low energy theory only the required D-terms and seesaw neutrino masses.Comment: 20 pages, 5 figures. Uses epsf. Minor corrections and added referenc
Declared funding and authorship by alcohol industry actors in the scientific literature: a bibliometric study
BACKGROUND
Alcohol industry actors are known to be involved in scientific research. Despite concerns regarding bias, the extent of involvement and coverage of this research are unknown.
METHODS
We aimed to investigate the extent and type of scientific research 1918-2019 which was supported by the alcohol industry, including alcohol companies themselves and other organizations, such as trade associations. We identified bibliographic records from the Web of Science suite of databases which have named alcohol companies or organizations in the fields relating to author affiliations and support declarations. We then ascertained trends in publications over time, type of support, funding, outlets (such as journal titles), subject areas covered (such as health) and named companies (such as Carlsberg) and organizations (such as Drinkaware).
RESULTS
The analysis included 13 481 unique records, 11 014 (82%) were authored or funded by alcohol companies and 2488 (18%) were authored or funded by other organizations. The majority of the records (90%, 12 157/13 481) were journal publications. The most common subject areas covered by the publications were biology (5415/13 481, 40%), chemistry (3937/13 481, 29%) and health (3707/13 481, 27%). In line with general publishing trends, there has been an overall increase in research funded or supported by alcohol companies and organizations since records began. The main exception is the steady decline in company author affiliations, particularly in health-related topics since the mid-1990s.
CONCLUSIONS
Alcohol companies and related organizations are extensively involved in or supporting scientific research according to data in Web of Science. This does not, however, necessarily reflect the totality of scientific research produced by alcohol companies and related organizations
The Fayet-Iliopoulos D-term and its renormalisation in the MSSM
We consider the renormalisation of the Fayet-Iliopoulos D-term in a
softly-broken supersymmetric gauge theory with a non-simple gauge group
containing an abelian factor, and present the associated beta-function through
three loops. We also include in an appendix the result for several abelian
factors. We specialise to the case of the minimal supersymmetric standard model
(MSSM), and investigate the behaviour of the Fayet-Iliopoulos coupling for
various boundary conditions at the unification scale. We focus particularly on
the case of non-standard soft supersymmetry breaking couplings, for which the
Fayet-Iliopoulos coupling evolves significantly between the unification scale
and the weak scale.Comment: 18 pages, Revtex, 2 figures. Expanded version including general
results for gauge groups with several abelian factors. Minor typos correcte
The Fayet-Iliopoulos D-term and its renormalisation in softly-broken supersymmetric theories
We consider the renormalisation of the Fayet-Iliopoulos D-term in a
softly-broken abelian supersymmetric theory, and calculate the associated
beta-function through three loops. We show that there exists (at least through
three loops) a renormalisation group invariant trajectory for the coefficient
of the D-term, corresponding to the conformal anomaly solution for the soft
masses and couplings.Comment: 30 pages, Revtex, 15 Figures. Minor changes, and inadvertent omission
of author from this abstract correcte
Leading Power Accuracy in Lattice Calculations of Parton Distributions
In lattice-QCD calculations of parton distribution functions (PDFs) via
large-momentum effective theory, the leading power (twist-three) correction
appears as due to the linear-divergent
self-energy of Wilson line in quasi-PDF operators. For lattice data with hadron
momentum of a few GeV, this correction is dominant in matching, as large
as 30\% or more. We show how to eliminate this uncertainty through choosing the
mass renormalization parameter consistently with the resummation scheme of the
infrared-renormalon series in perturbative matching coefficients. An example on
the lattice pion PDF data at GeV shows an improvement of matching
accuracy by a factor of more than in the expansion region .Comment: Updated to version published on PL
RG-invariant Sum Rule in a Generalization of Anomaly Mediated SUSY Breaking Models
We study a generalization of anomaly-mediated supersymmetry breaking (AMSB)
scenarios, under the assumption that the effects of the high-scale theory do
not completely decouple and D-term type contributions can be therefore present.
We investigate the effect of such possible D-term additional contributions to
soft scalar masses by requiring that, for non-vanishing, renormalizable Yukawa
couplings , the sum of squared soft supersymmetry breaking mass
parameters, , is RG-invariant, in the sense
that it becomes independent of the specific ultraviolet boundary conditions as
it occurs in the AMSB models. These type of models can avoid the problem of
tachyonic solutions for the slepton mass spectrum present in AMSB scenarios. We
implement the electroweak symmetry breaking condition and explore the sparticle
spectrum associated with this framework. To show the possible diversity of the
sparticle spectrum, we consider two examples, one in which the D-terms induce a
common soft supersymmetry breaking mass term for all sfermion masses, and
another one in which a light stop can be present in the spectrum.Comment: 24 pages, latex, 12 figure
Effect of Sodium Hypochlorite on Conventional and Heat-Treated Nickel-Titanium Endodontic Rotary Instruments – An In Vitro Study
Background/purpose: Sodium hypochlorite (NaOCl) is a highly alkaline solution which exhibits antimicrobial properties. However, it causes corrosion to endodontic rotary files. This study investigated the effect of NaOCl on the metal surface of five different unused endodontic rotary files in vitro. Materials and methods: Two non-heat-treated nickel-titanium (NiTi) files, ProTaper, BioRace, and three heat-treated NiTi files, VortexBlue, TRUShape, and EdgeFile X7 files, were immersed in 4% NaOCl for 5, 10, and 20 min, and 1, 6 and 24 h. The corrosion susceptibility was evaluated by visual inspection and scanning electron microscopy (SEM). Results: In the TRUShape group, the black particulate matter was mostly formed at the file\u27s curvature and shaft. A large amount of precipitate accumulated in the EdgeFile group. The extent and prevalence of surface defects were found to be consistently higher in EdgeFile X7 instruments than in any other instruments. EdgeFile X7 and TRUShape files exhibited a greater corrosive tendency to NaOCl than BioRace, ProTaper, and VortexBlue not only under visual inspection, but also under SEM analysis after prolonged immersion (1, 6, 24 h) in 4% NaOCl. However, shorter immersion periods (5, 10, 20 min) showed little surface corrosion across all experimental groups. Conclusion: Within the limitations of this study, EdgeFile X7 and TRUShape files exhibit greater corrosive tendencies to NaOCl in vitro than BioRace, ProTaper, and VortexBlue files after prolonged immersion in 4% NaOCl. However, shorter immersion periods, which more closely approximate clinical conditions during single root canal therapy, may not show surface corrosion across all experimental groups. © 2021 Association for Dental Sciences of the Republic of Chin
A new algorithm for sea ice melt pond fraction estimation from high-resolution optical satellite imagery
doi: 10.1029/2019JC015716Abstract Melt ponds occupy a large fraction of the Arctic sea ice surface during spring and summer. The fraction and distribution of melt ponds have considerable impacts on Arctic climate and ecosystem by reducing the albedo. There is an urgency to obtain improved accuracy and a wider coverage of melt pond fraction (MPF) data for studying these processes. MPF information has generally been acquired from optical imagery. Conventional MPF algorithms based on high-resolution optical sensors have treated melt ponds as features with constant reflectance; however, the spectral reflectance of ponds can vary greatly, even at a local scale. Here we use Sentinel-2 imagery to demonstrate those previous algorithms assuming fixed melt pond-reflectance greatly underestimate MPF. We propose a new algorithm (?LinearPolar?) based on the polar coordinate transformation that treats melt ponds as variable-reflectance features and calculates MPF across the vector between melt pond and bare ice axes. The angular coordinate ? of the polar coordinate system, which is only associated with pond fraction rather than reflectance, is used to determinate MPF. By comparing the new algorithm and previous methods with IceBridge optical imagery data, across a variety of Sentinel-2 images with melt ponds at various stages of development, we show that the RMSE value of the LinearPolar algorithm is about 30% lower than for the previous algorithms. Moreover, based on a sensitivity test, the new algorithm is also less sensitive to the subjective threshold for melt pond reflectance than previous algorithms.Peer reviewe
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