| 1. |
- He, Song, et al.
(författare)
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Kinematic numerators from the worldsheet : cubic trees from labelled trees
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- In this note we revisit the problem of explicitly computing tree-level scattering amplitudes in various theories in any dimension from worldsheet formulas. The latter are known to produce cubic-tree expansion of tree amplitudes with kinematic numerators automatically satisfying Jacobi-identities, once any half-integrand on the worldsheet is reduced to logarithmic functions. We review a natural class of worldsheet functions called "Cayley functions", which are in one-to-one correspondence with labelled trees, and natural expansions of known half-integrands onto them with coefficients that are particularly compact building blocks of kinematic numerators. We present a general formula expressing kinematic numerators of all cubic trees as linear combinations of coefficients of labelled trees, which satisfy Jacobi identities by construction and include the usual combinations in terms of master numerators as a special case. Our results provide an efficient algorithm, which is implemented in a MATHEMATICA package, for computing all tree amplitudes in theories including non-linear sigma model, special Galileon, Yang-Mills-scalar, Einstein-Yang-Mills and Dirac-Born-Infeld.
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| 2. |
- Meng, Linghui, et al.
(författare)
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Cardiovascular target organ damage could have been detected in sustained pediatric hypertension
- 2015
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Ingår i: Blood Pressure. - : Informa UK Limited. - 0803-7051 .- 1651-1999. ; 24:5, s. 284-292
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to assess sustained hypertension in children and its impact on cardiovascular target organ damage (TOD). Blood pressure (BP) was measured in children in Beijing in 2009. Primary hypertension was diagnosed based on three separate visits. Hypertensive children and normotensive children were followed up in 2011. According to these evaluations, three groups were defined: sustained hypertension, non-sustained hypertension and normotensive. Cardiovascular TOD and metabolic disorders were evaluated using pulse-wave velocity (PWV), carotid intima-media thickness (cIMT), and assessments of left ventricular structure and kidney function. A total of 3032 children aged 9-15 years participated in this survey, of whom 128 were diagnosed with hypertension after three separate BP measurements. Eighty out of 128 (62.5%) hypertensive and 158 normotensive children were available for follow-up in 2011. Forty-eight children were defined as having sustained hypertension, 38 as non-sustained hypertension and 152 as normotensive. Mean levels of brachial-ankle PWV (baPWV), left ventricular mass, left ventricular mass index (LVMI) and cIMT were significantly different between the three groups (p < 0.01). Compared to normotensives, the odds ratios and 95% confidence intervals for elevated LVM and cIMT were 5.27 (1.57-17.66) and 2.88 (1.03-8.09) in the non-sustained hypertensive group, and 3.28 (1.00-10.74) and 7.25 (2.69-19.58) in the sustained hypertensive group. The children with sustained hypertension have the highest risk of developing arterial stiffness, left ventricular hypertrophy and early blood vessel endothelium damage. The indices of cIMT, LVMI and PWV were useful to identify children at high risk of cardiovascular TOD.
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