96 research outputs found
The Systematics of Quarkonium Production at the LHC and Double Parton Fragmentation
In this paper we discuss the systematics of quarkonium production at the LHC.
In particular, we focus on the necessity to sum logs of the form log(Q/p_perp)
and log(p_perp/m_Q). We show that the former contributions are power
suppressed, while the latter, whose contribution in fragmentation is well
known, also arise in the short distance (i.e., non-fragmentation) production
mechanisms. Though these contributions are suppressed by powers of m_Q/p_perp,
they can be enhanced by inverse powers of v, the relative velocity between
heavy quarks in the quarkonium. In the limit p_perp >> m_Q short distance
production can be thought of as the fragmentation of a pair of partons (i.e.,
the heavy quark and anti-quark) into the final state quarkonium. We derive an
all order factorization theorem for this process in terms of double parton
fragmentation functions (DPFF) and calculate the one-loop anomalous dimension
matrix for the DPFF.Comment: 27 pages, 11 figure
On the suitability of the 4° à 4° GRACE mascon solutions for remote sensing Australian hydrology
Hydrological monitoring is essential for meaningful water-management policies and actions, especially where water resources are scarce and/or dwindling, as is the case in Australia. In this paper, we investigate the regional 4° Ă 4° mascon (mass concentration) GRACE solutions for Australia provided by GSFC (Goddard Space Flight Center, NASA) for their suitability in monitoring Australian hydrology, with a particular focus on the Murray-Darling Basin (MDB). Using principal component analysis (PCA) and multi-linear regression analysis (MLRA), the main components of spatial and temporal variability in the mascon solutions are analysed over the whole Australian continent and the MDB. The results are compared to those from global solutions provided by CSR (Center for Space Research, University of Texas at Austin, USA) and CNES/GRGS (Centre National d'Ătudes Spatiales/Groupe de Recherche de Geodesie Spatiale, France) and validated using data from the Tropical Rainfall Measuring Mission (TRMM), water storage changes predicted by the WaterGap Global Hydrological Model (WGHM) and the Global Land Data Assimilation System (GLDAS), and ground-truth (river-gauge) observations.For the challenging Australian case with generally weak hydrological signals, the mascon solutions provide similar results to those from the global solutions, with the advantage of not requiring additional filtering (destriping and smoothing) as, for example, is necessary for the CSR solutions. A further advantage of the mascon solutions is that they offer a higher temporal resolution (i.e., 10 days) compared to approximately monthly CSR solutions. Examining equivalent water volume (EWV) time series for the MDB shows a good cross-correlation (generally > 0.7) among the GRACE solutions when considering the whole basin, although lower (generally 0.6), with all time series appearing to visually follow the general behaviour of the river-gauge data, although the cross-correlations are relatively low (between 0.3 and 0.6).Research Highlights âș Mascon provides equivalent results as global CSR & CNES/GRGS solutions. âș All examined GRACE releases reveal seasonal & tropical north signals. âș GRACE, modelled hydrology & precipitation show similar behaviour Australia wide. âș GRACE solutions generally follow river gauge data
Controlled, parametric, individualized, 2D and 3D imaging measurements of aerosol deposition in the respiratory tract of healthy human volunteers: in vivo data analysis
Background: To provide a validation dataset for aerosol deposition modeling, a clinical trial was performed in which the inhalation parameters and the inhaled aerosol were controlled or characterized.Methods: Eleven, healthy, never-smokers, male participants completed the study. Each participant performed two inhalations of 99mTc-labeled aerosol from a vibrating mesh nebulizer, which differed by a single controlled parameter (aerosol particle size: âsmallâ or âlargeâ; inhalation: âdeepâ or âshallowâ; carrier gas: air or a heliumâoxygen mix). The deposition measurements were made by planar imaging, and single photon emission computed tomographyâcomputed tomography (SPECT-CT).Results: The difference between the mean activity measured by two-dimensional imaging and that delivered from the nebulizer was 2.7%, which was not statistically significant. The total activity deposited was significantly lower in the left lung than in the right lung (p<0.0001) with a mean ratio (left/right) of 0.87±0.1 standard deviation (SD). However, when normalized to lung air volume, the left lung deposition was significantly higher (p=0.0085) with a mean ratio of 1.08±0.12 SD. A comparison of the three-dimensional central-to-peripheral (nC/P3D) ratio showed that it was significantly higher for the left lung (p<0.0001) with a mean ratio (left/right) of 1.36±0.20 SD. The effect of particle size was statistically significant on the nC/P3D ratio (p=0.0014), extrathoracic deposition (p=0.0037), and 24-hr clearance (p<0.0001), contrary to the inhalation parameters, which showed no effect.Conclusions: This article presents the results of an analysis of the in vivo deposition data, obtained in a clinical study designed to provide data for model validation. This study has demonstrated the value of SPECT imaging over planar, the influence of particle size on regional distribution within the lung, and differences in deposition between the left and right lungs.<br/
Validated respiratory drug deposition predictions from 2D and 3D medical images with statistical shape models and convolutional neural networks
For the one billion sufferers of respiratory disease, managing their disease with inhalers crucially influences their quality of life. Generic treatment plans could be improved with the aid of computational models that account for patient-specific features such as breathing pattern, lung pathology and morphology. Therefore, we aim to develop and validate an automated computational framework for patient-specific deposition modelling. To that end, an image processing approach is proposed that could produce 3D patient respiratory geometries from 2D chest X-rays and 3D CT images. We evaluated the airway and lung morphology produced by our image processing framework, and assessed deposition compared to in vivo data. The 2D-to-3D image processing reproduces airway diameter to 9% median error compared to ground truth segmentations, but is sensitive to outliers of up to 33% due to lung outline noise. Predicted regional deposition gave 5% median error compared to in vivo measurements. The proposed framework is capable of providing patient-specific deposition measurements for varying treatments, to determine which treatment would best satisfy the needs imposed by each patient (such as disease and lung/airway morphology). Integration of patient-specific modelling into clinical practice as an additional decision-making tool could optimise treatment plans and lower the burden of respiratory diseases.</p
Controlled, Parametric, Individualized, 2D and 3D Imaging Measurements of Aerosol Deposition in the Respiratory Tract of Healthy Human Volunteers: In Vivo
2014 Massachusetts Family Impact Seminar: A Lot On Our Plate; Chronic Health Threats in Massachusetts
A Lot on Our Plate: Chronic Health Threats in Massachusetts is the fifth Massachusetts Family Impact Seminar, and is designed to emphasize a family perspective in policymaking on issues related to childhood obesity, cardiovascular disease, and type 2 diabetes. In general, Family Impact Seminars analyze the consequences an issue, policy, or program may have for families
Hard Scattering Factorization from Effective Field Theory
In this paper we show how gauge symmetries in an effective theory can be used
to simplify proofs of factorization formulae in highly energetic hadronic
processes. We use the soft-collinear effective theory, generalized to deal with
back-to-back jets of collinear particles. Our proofs do not depend on the
choice of a particular gauge, and the formalism is applicable to both exclusive
and inclusive factorization. As examples we treat the pi-gamma form factor
(gamma gamma* -> pi^0), light meson form factors (gamma* M -> M), as well as
deep inelastic scattering (e- p -> e- X), Drell-Yan (p pbar -> X l+ l-), and
deeply virtual Compton scattering (gamma* p -> gamma(*) p).Comment: 35 pages, 4 figures, typos corrected, journal versio
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