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

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

The role of psychological distress and sport participation on help-seeking among university student athletes

Student athletes are considered less likely to seek help than non-athlete students despite comparable rates of mental health difficulties. However, recent findings suggest certain variables may influence these differences. The present study used a secondary analysis of a national sample of university students to explore the role of psychological distress on help-seeking among student athletes and non-athlete students. Results indicate student athletes are less likely to consider help-seeking than non-athlete students. However, the association of psychological distress and help-seeking intention did not differ across level of sport participation. Unique predictors among student athletes indicate that athletes who are in fourth year and above, had previously sought help, or were experiencing greater psychological well-being demonstrated increased help-seeking intention. Psychological distress was associated with reduced intention. This study expands upon the growing body of student athlete help-seeking research and reinforces the importance of investigating strategies to better support this unique population

Characterizing Greenhouse Gas Emissions From Feed Yard Operations: Methods and Governing Factors

In this research, the uncertainty of commonly used GHG measurement methods was evaluated using Taylor series uncertainty analysis and a field study was performed to evaluate the feasibility of one of these methods. Taylor series uncertainty analysis was performed on three source-integrated methods: monostatic and bistatic open-path Fourier Transform Infrared Spectroscopy (OP-FTIR) and open-path tunable diode laser absorption spectroscopy (OP-TDLAS), and two source-specific methods: non-flow-through non-steady-state (NFT-NSS) and flow-through steady-state (FT-SS) chambers. The average systematic uncertainty for the three source-integrated methods was the same, 15.2%, when determining emission factors for methane (CH₄) and nitrous oxide (N₂O), except for OP-TDLAS, which did not measure N₂O. When determining emission factors from source-specific measurements, NFT-NSS chambers had an average systematic uncertainty of 21.2% and 24.6% for CH₄ and N₂O, respectively. The FT-SS chambers had an average systematic uncertainty of 13.5% when determining emission factors for CH₄ and N₂O by a single flux chamber measurement. A field study was conducted in the high plains of Texas at a feed yard with a potential maximum capacity of 50,000 head of cattle. The objective of this study was to determine the feasibility of using an OP-FTIR system to characterize emissions from a ground-level area source with precision. The feed yard was partitioned into multiple sources of CH₄ and N₂O that included enteric fermentation from the cattle, the manure in the pens, silage storage, manure storage, and a storage lagoon for runoff water from the pens. A bistatic OP-FTIR was placed 27 meters (m) north and parallel to the cattle pens with a path length of 550 m. A meteorological station was also located on this side of the feed yard, 5 meters north of the OP-FTIR path length. The 1-hour average CH₄ concentrations were 1.62-6.87 ppm and 1.36-4.97 ppm for downwind and upwind measurements, respectively. Measured 1-hour average N₂O concentrations were 168-514 ppb and 203-530 ppb for downwind and upwind measurements, respectively. The downwind and upwind N₂O measurements could not be statistically differentiated with the use of a single OP-FTIR system

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

Structural and Biochemical Studies of the Human pre-mRNA 3’-end Processing Complex

Most eukaryotic pre-mRNAs undergo 3′-end cleavage and polyadenylation prior to their export from the nucleus. A large number of proteins in several complexes participate in this 3′-end processing, including cleavage and polyadenylation specificity factor (CPSF) in mammals. The CPSF can be further divided into two sub-complexes: mPSF (mammalian polyadenylation specificity factor) which recognizes the AAUAAA polyadenylation signal (PAS) in the pre- mRNA, and mCF (mammalian cleavage factor) which cleaves the RNA. mPSF consists of CPSF160, CPSF30, WDR33, and hFip1. This thesis shows that AAUAAA PAS is recognized with ∼3 nM affinity by the CPSF160–WDR33–CPSF30 ternary complex, while the proteins alone or the binary complexes do not bind the PAS with high affinity. Furthermore, it is shown that mutations of residues in CPSF30 that have van der Waals interactions with the bases of the PAS lead to a sharp reduction in the affinity. Finally, variations of the AAUAAA or removing the bases downstream also reduce the binding significantly. This thesis goes on to characterize the structure of the CPSF30—hFip1 complex, which was not observed in the previous EM structures of the mPSF. It was known that CPSF30 ZF4–ZF5 recruits the hFip1 subunit of CPSF, although the details of this interaction have not been characterized. Here we report the crystal structure of human CPSF30 ZF4–ZF5 in complex with residues 161–200 of hFip1 at 1.9 Å. Unexpectedly, the structure reveals one hFip1 molecule binding to each ZF4 and ZF5, with a conserved mode of interaction. Mutagenesis studies confirm that the CPSF30–hFip1 complex has 1:2 stoichiometry in vitro. Mutation of each binding site in CPSF30 still allows one copy of hFip1 to bind, while mutation of both sites abrogates binding. Our fluorescence polarization binding assays show that ZF4 has higher affinity for hFip1, with a Kd of 1.8 nM. We also demonstrate that two copies of the catalytic module of poly(A) polymerase (PAP) are recruited by the CPSF30–hFip1 complex in vitro, and both hFip1 binding sites in CPSF30 can support polyadenylation