3,161 research outputs found
Extending the MINLO method
We consider improving POWHEG+MINLO simulations, so as to also render them NLO
accurate in the description of observables receiving contributions from events
with lower parton multiplicity than present in their underlying NLO
calculation. On a conceptual level we follow the strategy of the so-called
MINLO' programs. Whereas the existing MINLO' framework requires explicit
analytic input from higher order resummation, here we derive an effective
numerical approximation to these ingredients, by imposing unitarity. This
offers a way of extending the MINLO' method to more complex processes,
complementary to the known route which uses explicit computations of
high-accuracy resummation inputs. Specifically, we have focused on
Higgs-plus-two-jet production (HJJ) and related processes. We also consider how
one can cover three units of multiplicity at NLO accuracy, i.e. we consider how
the HJJ-MINLO simulation may yield NLO accuracy for inclusive H, HJ, and HJJ
quantities. We perform a feasibility study assessing the potential of these
ideas.Comment: 66 pages, 22 figures; v2 references added; v3=JHEP, improved
readabilit
Knowledge-based system V and V in the Space Station Freedom program
Knowledge Based Systems (KBS's) are expected to be heavily used in the Space Station Freedom Program (SSFP). Although SSFP Verification and Validation (V&V) requirements are based on the latest state-of-the-practice in software engineering technology, they may be insufficient for Knowledge Based Systems (KBS's); it is widely stated that there are differences in both approach and execution between KBS V&V and conventional software V&V. In order to better understand this issue, we have surveyed and/or interviewed developers from sixty expert system projects in order to understand the differences and difficulties in KBS V&V. We have used this survey results to analyze the SSFP V&V requirements for conventional software in order to determine which specific requirements are inappropriate for KBS V&V and why they are inappropriate. Further work will result in a set of recommendations that can be used either as guidelines for applying conventional software V&V requirements to KBS's or as modifications to extend the existing SSFP conventional software V&V requirements to include KBS requirements. The results of this work are significant to many projects, in addition to SSFP, which will involve KBS's
Preparing millennials as digital citizens and socially and environmentally responsible business professionals in a socially irresponsible climate
As of 2015, a millennial born in the 1990's became the largest population in
the workplace and are still growing. Studies indicate that a millennial is tech
savvy but lag in the exercise of digital responsibility. In addition, they are
passive towards environmental sustainability and fail to grasp the importance
of social responsibility. This paper provides a review of such findings
relating to business communications educators in their classrooms. The
literature should enable the development of a millennial as an excellent global
citizen through business communications curricula that emphasizes digital
citizenship, environmental sustainability and social responsibility. The
impetus for this work is to provide guidance in the development of courses and
teaching strategies customized to the development of each millennial as a
digital, environmental and socially responsible global citizen
Finite quark-mass effects in the NNLOPS POWHEG+MiNLO Higgs generator
We include finite top- and bottom-mass effects in the next-to-next-to-leading
order parton shower (NNLOPS) event generator for inclusive Higgs boson
production in gluon fusion based upon the POWHEG+MiNLO approach. Since
fixed-order results for quark-mass effects only reach NLO accuracy, we add them
to the NNLOPS generator at that accuracy. We explore uncertainties related to
the unknown all-order logarithmic structure of bottom-mass effects by comparing
the assumption of full exponentiation to no exponentiation at all.
Phenomenological results showing the effects of finite quark-masses in the
NNLOPS simulation are presented. These suggest that the aforementioned
uncertainty is well contained within the envelope of plain renormalization and
factorization scale uncertainties.Comment: 23 pages, 7 figure
NNLOPS simulation of Higgs boson production
We detail a simulation of Higgs boson production via gluon fusion, accurate
at next-to-next-to-leading order in the strong coupling, including matching to
a parton shower, yielding a fully exclusive, hadron-level description of the
final-state. The approach relies on the POWHEG method for merging the NLO Higgs
plus jet cross-section with the parton shower, and on the MINLO method to
simultaneously achieve NLO accuracy for inclusive Higgs boson production. The
NNLO accuracy is reached by a reweighting procedure making use of the HNNLO
program.Comment: 25 pages, 10 figures. Very minor clarifications in the text for v
Merging WW and WW+jet with MINLO
We present a simulation program for the production of a pair of W bosons in
association with a jet, that can be used in conjunction with general-purpose
shower Monte Carlo generators, according to the POWHEG method. We have further
adapted and implemented the MINLO' method on top of the NLO calculation
underlying our WW+jet generator. Thus, the resulting simulation achieves NLO
accuracy not only for inclusive distributions in WW+jet production but also WW
production, i.e. when the associated jet is not resolved, without the
introduction of any unphysical merging scale. This work represents the first
extension of the MINLO' method, in its original form, to the case of a genuine
underlying 2->2 process, with non-trivial virtual corrections.Comment: 22 pages, 9 figure
Molecular brakes regulating mTORC1 activation in skeletal muscle following synergist ablation
The goal of the current work was to profile positive (mTORC1 activation, autocrine/paracrine growth factors) and negative [AMPK, unfolded protein response (UPR)] pathways that might regulate overload-induced mTORC1 (mTOR complex 1) activation with the hypothesis that a number of negative regulators of mTORC1 will be engaged during a supraphysiological model of hypertrophy. To achieve this, mTORC1- IRS-1/2 signaling, BiP/CHOP/IRE1, and AMPK activation were determined in rat plantaris muscle following synergist ablation (SA). SA resulted in significant increases in muscle mass of 4% per day throughout the 21 days of the experiment. The expression of the insulin-like growth factors (IGF) were high throughout the 21st day of overload. However, IGF signaling was limited, since IRS-1 and -2 were undetectable in the overloaded muscle from day 3 to day 9. The decreases in IRS-1/2 protein were paralleled by increases in GRB10 Ser501/503 and S6K1 Thr389 phosphorylation, two mTORC1 targets that can destabilize IRS proteins. PKB Ser473 phosphorylation was higher from 3– 6 days, and this was associated with increased TSC2 Thr939 phosphorylation. The phosphorylation of TSC2 Thr1345 (an AMPK site) was also elevated, whereas phosphorylation at the other PKB site, Thr1462, was unchanged at 6 days. In agreement with the phosphorylation of Thr1345, SA led to activation of AMPK1 during the initial growth phase, lasting the first 9 days before returning to baseline by day 12. The UPR markers CHOP and BiP were elevated over the first 12 days following ablation, whereas IRE1 levels decreased. These data suggest that during supraphysiological muscle loading at least three potential molecular brakes engage to downregulate mTORC1. m
Finite element model of an impact on a palmar pad from a snowboard wrist protector
Wrist injuries are the most common types of injury in snowboarding. Protectors can reduce injury risk by limiting wrist hyperextension and attenuating impact forces. There are a range of wrist protector concepts available, but it is unclear if any particular design is more effective. The aim of this study was to develop and validate a finite element model of an impact on the palmar pad from a protector. Pad material from a protector was characterised to obtain stress vs strain data, and determine whether it was rate dependent. Material data was implemented into a finite element model to predict impact behavior at 2.5 J. Four material models were investigated, with an Ogden model paired with a Prony series providing the best agreement to experimental data. Future work will build a model of a complete protector for predicting the protective levels of these products
Improving NLO-parton shower matched simulations with higher order matrix elements
In recent times the algorithms for the simulation of hadronic collisions have
been subject to two substantial improvements: the inclusion, within parton
showering, of exact higher order tree level matrix elements (MEPS) and,
separately, next-to-leading order corrections (NLOPS). In this work we examine
the key criteria to be met in merging the two approaches in such a way that the
accuracy of both is preserved, in the framework of the POWHEG approach to
NLOPS. We then ask to what extent these requirements may be fulfilled using
existing simulations, without modifications. The result of this study is a
pragmatic proposal for merging MEPS and NLOPS events to yield much improved
MENLOPS event samples. We apply this method to W boson and top quark pair
production. In both cases results for distributions within the remit of the NLO
calculations exhibit no discernible changes with respect to the pure NLOPS
prediction; conversely, those sensitive to the distribution of multiple hard
jets assume, exactly, the form of the corresponding MEPS results.Comment: 38 pages, 17 figures. v2: added citations and brief discussion of
related works, MENLOPS prescription localized in a subsection. v3: cited 4
more MEPS works in introduction
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