327 research outputs found
Структура износостойких покрытий кабонитрида циркония
A structure of zirconium carbonitride coatings obtained by an arc cathodic deposition in the medium of reactant mixture of nitrogen and acetylene was investigated. Using X-ray diffraction and X-ray photoelectron spectroscopy it was shown that the coatings consist of both ultra dispersive δ phase zirconium carbonitride and amorphous carbon containing considerable amount of sp3 bonds. The coatings were textured greatly with texture axis (111). The texture degree influenced a substrate material like tool steel X12M and cemented carbide BK6.Исследована кристаллическая структура покрытий карбонитрида циркония, полученных катодно-дуговым осаждением в реакционной среде смеси газов азота и ацетилена. Методами рентгенографии и рентгеновской фотоэлектронной спектроскопии показано, что структура покрытия образована ультрадисперсной δ-фазой карбонитрида циркония и аморфного алмазоподобного углерода с большим содержанием sр3-связанных атомов. Покрытия сильно текстурированы с осью текстуры (111). Показано, что на степень текстурирования значительно влияет материал основы, в качестве которой использовалась инструментальная сталь Х12М и твердый сплав ВК6
Constraints on supersymmetry with light third family from LHC data
We present a re-interpretation of the recent ATLAS limits on supersymmetry in
channels with jets (with and without b-tags) and missing energy, in the context
of light third family squarks, while the first two squark families are
inaccessible at the 7 TeV run of the Large Hadron Collider (LHC). In contrast
to interpretations in terms of the high-scale based constrained minimal
supersymmetric standard model (CMSSM), we primarily use the low-scale
parametrisation of the phenomenological MSSM (pMSSM), and translate the limits
in terms of physical masses of the third family squarks. Side by side, we also
investigate the limits in terms of high-scale scalar non-universality, both
with and without low-mass sleptons. Our conclusion is that the limits based on
0-lepton channels are not altered by the mass-scale of sleptons, and can be
considered more or less model-independent.Comment: 20 pages, 8 figures, 2 tables. Version published in JHE
Interpreting a 1 fb^-1 ATLAS Search in the Minimal Anomaly Mediated Supersymmetry Breaking Model
Recent LHC data significantly extend the exclusion limits for supersymmetric
particles, particularly in the jets plus missing transverse momentum channels.
The most recent such data have so far been interpreted by the experiment in
only two different supersymmetry breaking models: the constrained minimal
supersymmetric standard model (CMSSM) and a simplified model with only squarks
and gluinos and massless neutralinos. We compare kinematical distributions of
supersymmetric signal events predicted by the CMSSM and anomaly mediated
supersymmetry breaking (mAMSB) before calculating exclusion limits in mAMSB. We
obtain a lower limit of 900 GeV on squark and gluino masses at the 95%
confidence level for the equal mass limit, tan(beta)=10 and mu>0.Comment: 18 pages, 11 figure
Flavor Mediation Delivers Natural SUSY
If supersymmetry (SUSY) solves the hierarchy problem, then naturalness
considerations coupled with recent LHC bounds require non-trivial superpartner
flavor structures. Such "Natural SUSY" models exhibit a large mass hierarchy
between scalars of the third and first two generations as well as degeneracy
(or alignment) among the first two generations. In this work, we show how this
specific beyond the standard model (SM) flavor structure can be tied directly
to SM flavor via "Flavor Mediation". The SM contains an anomaly-free SU(3)
flavor symmetry, broken only by Yukawa couplings. By gauging this flavor
symmetry in addition to SM gauge symmetries, we can mediate SUSY breaking via
(Higgsed) gauge mediation. This automatically delivers a natural SUSY spectrum.
Third-generation scalar masses are suppressed due to the dominant breaking of
the flavor gauge symmetry in the top direction. More subtly, the
first-two-generation scalars remain highly degenerate due to a custodial U(2)
symmetry, where the SU(2) factor arises because SU(3) is rank two. This
custodial symmetry is broken only at order (m_c/m_t)^2. SUSY gauge coupling
unification predictions are preserved, since no new charged matter is
introduced, the SM gauge structure is unaltered, and the flavor symmetry treats
all matter multiplets equally. Moreover, the uniqueness of the anomaly-free
SU(3) flavor group makes possible a number of concrete predictions for the
superpartner spectrum.Comment: 17 pages, 7 figures, 2 tables. v2 references added, minor changes to
flavor constraints and a little discussion adde
Presence of mechanical dyssynchrony in Duchenne Muscular dystrophy: a cardiac MRI study utilizing cross correlation delay
New perturbation theory representation of the conformal symmetry breaking effects in gauge quantum field theory models
We propose a hypothesis on the detailed structure for the representation of
the conformal symmetry breaking term in the basic Crewther relation generalized
in the perturbation theory framework in QCD renormalized in the scheme. We establish the validity of this representation in the
approximation. Using the variant of the generalized Crewther
relation formulated here allows finding relations between specific
contributions to the QCD perturbation series coefficients for the flavor
nonsinglet part of the Adler function for the electron-positron
annihilation in hadrons and to the perturbation series coefficients for the
Bjorken sum rule for the polarized deep-inelastic lepton-nucleon
scattering. We find new relations between the coefficients of
and . Satisfaction of one of them serves as an
additional theoretical verification of the recent computer analytic
calculations of the terms of order in the expressions for these
two quantities.Comment: 12 pages, Title modified, abstract modified, improved and extended
variant of the talks, presented at Int. Seminar "Quarks-2010" (6-12 June,
2010, Kolomna) and Int. Workshop Hadron Structure and QCD: From Low to High
Energies (5-9 July 2010, Gatchina
Recommended from our members
Omega-3 polyunsaturated fatty acids preserve retinal function in type 2 diabetic mice
Objective: Diabetic retinopathy (DR) is associated with hyperglycemia-driven microvascular pathology and neuronal compromise in the retina. However, DR is also linked to dyslipidemia. As omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) are protective in proliferative retinopathy, we investigated the capacity of ω-3PUFAs to preserve retinal function in a mouse model of type 2 diabetes mellitus (T2DM). Design: Male leptin-receptor-deficient (db/db) mice were maintained for 22 weeks (4 weeks–26 weeks of life) on calorically and compositionally matched diets, except for 2% enrichment in either ω-3 or ω-6PUFAs. Visual function was assessed at 9, 14 and 26 weeks by electroretinography. Retinal capillary and neuronal integrity, as well as glucose challenge responses, were assessed on each diet. Results: The ω-3PUFA diet significantly preserved retinal function in the mouse model of T2DM to levels similar to those observed in nondiabetic control mice on normal chow. Conversely, retinal function gradually deteriorated in db/db mice on a ω-6PUFA-rich diet. There was also an enhanced ability of ω-3PUFA-fed mice to respond to glucose challenge. The protection of visual function appeared to be independent of cytoprotective or anti-inflammatory effects of ω-3PUFAs. Conclusion: This study identifies beneficial effects of dietary ω-3PUFAs on visual function in T2DM. The data are consistent with dyslipidemia negatively impacting retinal function. As ω-3PUFA lipid dietary interventions are readily available, safe and inexpensive, increasing ω-3PUFA intake in diabetic patients may slow the progression of vision loss in T2DM
- …