1,381 research outputs found

    Jet p_T Resummation in Higgs Production at NNLL'+NNLO

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    We present predictions for Higgs production via gluon fusion with a p_T veto on jets and with the resummation of jet-veto logarithms at NNLL'+$NNLO order. These results incorporate explicit O(alphas^2) calculations of soft and beam functions, which include the dominant dependence on the jet radius R. In particular the NNLL' order accounts for the correct boundary conditions for the N3LL resummation, for which the only unknown ingredients are higher-order anomalous dimensions. We use scale variations in a factorization theorem in both rapidity and virtuality space to estimate the perturbative uncertainties, accounting for both higher fixed-order corrections as well as higher-order towers of jet-p_T logarithms. This formalism also predicts the correlations in the theory uncertainty between the exclusive 0-jet and inclusive 1-jet bins. At the values of R used experimentally, there are important corrections due to jet algorithm clustering that include logarithms of R. Although we do not sum logarithms of R, we do include an explicit contribution in our uncertainty estimate to account for higher-order jet clustering logarithms. Precision predictions for this H+0-jet cross section and its theoretical uncertainty are an integral part of Higgs analyses that employ jet binning.Comment: 24 pages, 11 figure

    Keys from the past: Unlocking the power of eighteenth-century contrapuntal pedagogies

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    How did eighteenth-century musicians learn to compose, and how were they able to produce musical works with such comparative ease and fluency? What were the strategies at play that enabled even the most workman-like of composers to produce vast amounts of competent music, and how was it possible for almost any professional keyboard player to improvise a passable fugue? It is only recently that scholars have sought the answers to such questions. Groundbreaking work by Gjerdigen (1988; 2007a), Porter (2000; 2002), Renwick (1995), and others, provides a fascinating glimpse of the working methods of eighteenth-century musicians, and also offers implications for contemporary music theory teaching. Historically, training musicians in the art of composition has been one of theory’s primary goals, and it could be argued that the ability to replicate a musical style is a true litmus test of deep understanding. Theory instruction in Australia, however, often falls short in this regard, confining itself instead to drilling rudiments, basic voice-leading tasks, and superficial analysis such as labeling chords. This paper aims to show how theory teaching can be reenvisioned to include style composition as a pedagogically powerful and rewarding activity. It also highlights the key usefulness of eighteenth-century pedagogies in unlocking windows into the common-practice idiom

    Hypertension in mice lacking 11beta-hydroxysteroid dehydrogenase type 2

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    Deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) in humans leads to the syndrome of apparent mineralocorticoid excess (SAME), in which cortisol illicitly occupies mineralocorticoid receptors, causing sodium retention, hypokalemia, and hypertension. However, the disorder is usually incompletely corrected by suppression of cortisol, suggesting additional and irreversible changes, perhaps in the kidney. To examine this further, we produced mice with targeted disruption of the 11β-HSD2 gene. Homozygous mutant mice (11β-HSD2(–/–)) appear normal at birth, but ∼50% show motor weakness and die within 48 hours. Both male and female survivors are fertile but exhibit hypokalemia, hypotonic polyuria, and apparent mineralocorticoid activity of corticosterone. Young adult 11β-HSD2(–/–) mice are markedly hypertensive, with a mean arterial blood pressure of 146 ± 2 mmHg, compared with 121 ± 2 mmHg in wild-type controls and 114 ± 4 mmHg in heterozygotes. The epithelium of the distal tubule of the nephron shows striking hypertrophy and hyperplasia. These histological changes do not readily reverse with mineralocorticoid receptor antagonism in adulthood. Thus, 11β-HSD2(–/–) mice demonstrate the major features of SAME, providing a unique rodent model to study the molecular mechanisms of kidney resetting leading to hypertension. J. Clin. Invest. 103:683–689 (1999

    Climate Change and Biosphere Response: Unlocking the Collections Vault

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    Natural history collections (NHCs) are an important source of the long-term data needed to understand how biota respond to ongoing anthropogenic climate change. These include taxon occurrence data for ecological modeling, as well as information that can be used to reconstruct mechanisms through which biota respond to changing climates. The full potential of NHCs for climate change research cannot be fully realized until high-quality data sets are conveniently accessible for research, but this requires that higher priority be placed on digitizing the holdings most useful for climate change research (e.g., whole-biota studies, time series, records of intensively sampled common taxa). Natural history collections must not neglect the proliferation of new information from efforts to understand how present-day ecosystems are responding to environmental change. These new directions require a strategic realignment for many NHC holders to complement their existing focus on taxonomy and systematics. To set these new priorities, we need strong partnerships between NHC holders and global change biologists

    Parent of Origin, Mosaicism, and Recurrence Risk: Probabilistic Modeling Explains the Broken Symmetry of Transmission Genetics

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    Most new mutations are observed to arise in fathers, and increasing paternal age positively correlates with the risk of new variants. Interestingly, new mutations in X-linked recessive disease show elevated familial recurrence rates. In male offspring, these mutations must be inherited from mothers. We previously developed a simulation model to consider parental mosaicism as a source of transmitted mutations. In this paper, we extend and formalize the model to provide analytical results and flexible formulas. The results implicate parent of origin and parental mosaicism as central variables in recurrence risk. Consistent with empirical data, our model predicts that more transmitted mutations arise in fathers and that this tendency increases as fathers age. Notably, the lack of expansion later in the male germline determines relatively lower variance in the proportion of mutants, which decreases with paternal age. Subsequently, observation of a transmitted mutation has less impact on the expected risk for future offspring. Conversely, for the female germline, which arrests after clonal expansion in early development, variance in the mutant proportion is higher, and observation of a transmitted mutation dramatically increases the expected risk of recurrence in another pregnancy. Parental somatic mosaicism considerably elevates risk for both parents. These findings have important implications for genetic counseling and for understanding patterns of recurrence in transmission genetics. We provide a convenient online tool and source code implementing our analytical results. These tools permit varying the underlying parameters that influence recurrence risk and could be useful for analyzing risk in diverse family structures

    Voting: What Has Changed, What Hasn't, & Why: Research Bibliography

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    Since the origins of the Caltech/MIT Voting Technology Project in the fall of 2000, there has been an explosion of research and analysis on election administration and voting technology. As we worked throughout 2012 on our most recent study, Voting: What Has Changed, What Hasn’t, & What Needs Improvement, we found many more research studies. In this research bibliography, we present the research literature that we have found; future revisions of this research bibliography will update this list.Carnegie Corporation of New Yor
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