10,821 research outputs found
Quadratic Contributions of Softly Broken Supersymmetry in the Light of Loop Regularization
Loop regularization (LORE) is a novel regularization scheme in modern quantum
field theories. It makes no change to the spacetime structure and respects both
gauge symmetries and supersymmetry. As a result, LORE should be useful in
calculating loop corrections in supersymmetry phenomenology. To demonstrate
further its power, in this article we revisit in the light of LORE the old
issue of the absence of quadratic contributions (quadratic divergences) in
softly broken supersymmetric field theories. It is shown explicitly by Feynman
diagrammatic calculations that up to two loops the Wess-Zumino model with soft
supersymmetry breaking terms (WZ' model), one of the simplest models with the
explicit supersymmetry breaking, is free of quadratic contributions. All the
quadratic contributions cancel with each other perfectly, which is consistent
with results dictated by the supergraph techniques.Comment: 25 pages, 3 figures; accepted versio
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Global Metabolic Shifts in Age and Alzheimer's Disease Mouse Brains Pivot at NAD+/NADH Redox Sites.
Age and Alzheimer's disease (AD) share some common features such as cognitive impairments, memory loss, metabolic disturbances, bioenergetic deficits, and inflammation. Yet little is known on how systematic shifts in metabolic networks depend on age and AD. In this work, we investigated the global metabolomic alterations in non-transgenic (NTg) and triple-transgenic (3xTg-AD) mouse brain hippocampus as a function of age by using untargeted Ultrahigh Performance Liquid Chromatography-tandem Mass Spectroscopy (UPLC-MS/MS). We observed common metabolic patterns with aging in both NTg and 3xTg-AD brains involved in energy-generating pathways, fatty acids oxidation, glutamate, and sphingolipid metabolism. We found age-related downregulation of metabolites from reactions in glycolysis that consumed ATP and in the TCA cycle, especially at NAD+/NADH-dependent redox sites, where age- and AD-associated limitations in the free NADH may alter reactions. Conversely, metabolites increased in glycolytic reactions in which ATP is produced. With age, inputs to the TCA cycle were increased including fatty acid β-oxidation and glutamine. Overall age- and AD-related changes were > 2-fold when comparing the declines of upstream metabolites of NAD+/NADH-dependent reactions to the increases of downstream metabolites (p = 10-5, n = 8 redox reactions). Inflammatory metabolites such as ceramides and sphingosine-1-phosphate also increased with age. Age-related decreases in glutamate, GABA, and sphingolipid were seen which worsened with AD genetic load in 3xTg-AD brains, possibly contributing to synaptic, learning- and memory-related deficits. The data support the novel hypothesis that age- and AD-associated metabolic shifts respond to NAD(P)+/NAD(P)H redox-dependent reactions, which may contribute to decreased energetic capacity
Neural Reranking for Named Entity Recognition
We propose a neural reranking system for named entity recognition (NER). The
basic idea is to leverage recurrent neural network models to learn
sentence-level patterns that involve named entity mentions. In particular,
given an output sentence produced by a baseline NER model, we replace all
entity mentions, such as \textit{Barack Obama}, into their entity types, such
as \textit{PER}. The resulting sentence patterns contain direct output
information, yet is less sparse without specific named entities. For example,
"PER was born in LOC" can be such a pattern. LSTM and CNN structures are
utilised for learning deep representations of such sentences for reranking.
Results show that our system can significantly improve the NER accuracies over
two different baselines, giving the best reported results on a standard
benchmark.Comment: Accepted as regular paper by RANLP 201
Explicitly Broken Supersymmetry with Exactly Massless Moduli
There is an avatar of the little hierarchy problem of the MSSM in
3-dimensional supersymmetry. We propose a solution to this problem in AdS
based on the AdS/CFT correspondence. The bulk theory is a supergravity theory
in which U(1) U(1) R-symmetry is gauged by Chern-Simons fields. The
bulk theory is deformed by a boundary term quadratic in the gauge fields. It
breaks SUSY completely and sources an exactly marginal operator in the dual
CFT. SUSY breaking is communicated by gauge interactions to bulk scalar fields
and their spinor superpartners. Since the R-charges of scalar and spinor
differ, this generates a SUSY breaking shift of their masses. The Ward identity
facilitates the calculation of these mass shifts to any desired order in the
strength of the deformation. Moduli fields are massless -neutral bulk
scalars with vanishing potential in the undeformed theory. These properties are
maintained to all orders in the deformation despite the fact that moduli couple
in the bulk to loops of R-charged fields.Comment: Match to published version. All order corrections, i.e. exact results
after SUSY breaking, are show
Quantum Electroweak Symmetry Breaking Through Loop Quadratic Contributions
Based on two postulations that (i) the Higgs boson has a large bare mass GeV at the characteristic energy scale which defines
the standard model (SM) in the ultraviolet region, and (ii) quadratic
contributions of Feynman loop diagrams in quantum field theories are physically
meaningful, we show that the SM electroweak symmetry breaking is induced by the
quadratic contributions from loop effects. As the quadratic running of Higgs
mass parameter leads to an additive renormalization, which distinguishes from
the logarithmic running with a multiplicative renormalization, the symmetry
breaking occurs once the sliding energy scale moves from down to a
transition scale at which the additive renormalized Higgs
mass parameter gets to change the sign. With the input of
current experimental data, this symmetry breaking energy scale is found to be
GeV, which provides another basic energy scale for the
SM besides . Studying such a symmetry breaking mechanism could play an
important role in understanding both the hierarchy problem and naturalness
problem. It also provides a possible way to explore the experimental
implications of the quadratic contributions as lies within the
probing reach of the LHC and the future Great Collider.Comment: 10 pages, 2 figures, published versio
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