Acute viral bronchiolitis in South Africa : diagnostic flow

Bronchiolitis may be diagnosed on the basis of clinical signs and symptoms. In a young child, the diagnosis can be made on the clinical pattern of wheezing and hyperinflation. Clinical symptoms and signs typically start with an upper respiratory prodrome, including rhinorrhoea, low-grade fever, cough and poor feeding, followed 1 - 2 days later by tachypnoea, hyperinflation and wheeze as a consequence of airway inflammation and air trapping. The illness is generally self limiting, but may become more severe and include signs such as grunting, nasal flaring, subcostal chest wall retractions and hypoxaemia. The most reliable clinical feature of bronchiolitis is hyperinflation of the chest, evident by loss of cardiac dullness on percussion, an upper border of the liver pushed down to below the 6th intercostal space, and the presence of a Hoover sign (subcostal recession, which occurs when a flattened diaphragm pulls laterally against the lower chest wall). Measurement of peripheral arterial oxygen saturation is useful to indicate the need for supplemental oxygen. A saturation of <92% at sea level and 90% inland indicates that the child has to be admitted to hospital for supplemental oxygen. Chest radiographs are generally unhelpful and not required in children with a clear clinical diagnosis of bronchiolitis. Blood tests are not needed routinely. Complete blood count tests have not been shown to be useful in diagnosing bronchiolitis or guiding its therapy. Routine measurement of C-reactive protein does not aid in management and nasopharyngeal aspirates are not usually done. Viral testing adds little to routine management. Risk factors in patients with severe bronchiolitis that require hospitalisation and may even cause death, include prematurity, congenital heart disease and congenital lung malformations.http://www.samj.org.zaam2016Paediatrics and Child Healt

Acute viral bronchiolitis in South Africa : viral aetiology and clinical epidemiology

Bronchiolitis is a viral-induced lower respiratory tract infection that occurs predominantly in children <2 years of age, particularly infants. Many viruses have been proven or attributed to cause bronchiolitis, including and most commonly the respiratory syncytial virus (RSV) and rhinovirus. RSV is responsible for more severe disease and complications (including hospitalisation) in bronchiolitis patients. Whereas bronchiolitis is exclusively due to respiratory viral infections, with little evidence of bacterial co-infection, the former could nevertheless predispose to superimposed bacterial infections. Although data support an interaction between RSV and pneumococcal superimposed infections, it should be noted that this specifically refers to children who are hospitalised with RSV-associated pneumonia, and not to children with bronchiolitis or milder outpatient RSV-associated illness. As such, empiric antibiotic treatment against pneumococcus in children with RSV-associated pneumonia is only warranted in cases of hospitalisation and when the clinical syndrome is more in keeping with pneumonia than uncomplicated bronchiolitis. In South Africa, the peak in the RSV season varies only slightly by province, with onset in February, and lasting until June. The important implication of these new seasonality findings is that where prophylaxis is possible, as in the case of RSV, it should be commenced in January of each year.http://www.samj.org.zaam2016Paediatrics and Child Healt

Acute viral bronchiolitis in South Africa : strategies for management and prevention

Management of acute viral bronchiolitis is largely supportive. There is currently no proven effective therapy other than oxygen for hypoxic children. The evidence indicates that there is no routine benefit from inhaled, rapid short-acting bronchodilators, adrenaline or ipratropium bromide for children with acute viral bronchiolitis. Likewise, there is no demonstrated benefit from routine use of inhaled or oral corticosteroids, inhaled hypertonic saline nebulisation, montelukast or antibiotics. The last should be reserved for children with severe disease, when bacterial co-infection is suspected. Prevention of respiratory syncytial virus (RSV) disease remains a challenge. A specific RSV monoclonal antibody, palivizumab, administered as an intramuscular injection, is available for children at risk of severe bronchiolitis, including premature infants, young children with chronic lung disease, immunodeficiency, or haemodynamically significant congenital heart disease. Prophylaxis should be commenced at the start of the RSV season and given monthly during the season. The development of an RSV vaccine may offer a more effective alternative to prevent disease, for which the results of clinical trials are awaited. Education of parents or caregivers and healthcare workers about diagnostic and management strategies should include the following: bronchiolitis is caused by a virus; it is seasonal; it may start as an upper respiratory tract infection with low-grade fever; symptoms are cough and wheeze, often with fast breathing; antibiotics are generally not needed; and the condition is usually self limiting, although symptoms may occur for up to 4 weeks in some children.http://www.samj.org.zaam2016Paediatrics and Child Healt

The dual parametrization for gluon GPDs

We consider the application of the dual parametrization for the case of gluon GPDs in the nucleon. This provides opportunities for the more flexible modeling unpolarized gluon GPDs in a nucleon which in particular contain the invaluable information on the fraction of nucleon spin carried by gluons. We perform the generalization of Abel transform tomography approach for the case of gluons. We also discuss the skewness effect in the framework of the dual parametrization. We strongly suggest to employ the fitting strategies based on the dual parametrization to extract the information on GPDs from the experimental data.Comment: 37 pages, 2 figure

An attempt to understand exclusive pi+ electroproduction

Hard exclusive pi+ electroproduction is investigated within the handbag approach. The prominent role of the pion-pole contribution is demonstrated. It is also shown that the experimental data require a twist-3 effect which ensues from the helicity-flip generalized parton distribution H_T and the twist-3 pion wave function. The results calculated from this handbag approach are compared in detail with the experimental data on cross sections and spin asymmetries measured with a polarized target. It is also commented on consequences of this approach for exclusive \pi^0 and vector-meson electroproduction.Comment: 35 pages, 12 figures, using Latex, a number of additional comments have been included in the text, e.g. in paragraph above (3) or at end of sect.

Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV

The three-body photodisintegration of 3He has been measured with the CLAS detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first time to cover a wide momentum and angular range for the two outgoing protons. Three kinematic regions dominated by either two- or three-body contributions have been distinguished and analyzed. The measured cross sections have been compared with results of a theoretical model, which, in certain kinematic ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications: removed 2 figures, improvements on others, a few minor modifications to the tex

eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure

A Kinematically Complete Measurement of the Proton Structure Function F2 in the Resonance Region and Evaluation of Its Moments

We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.Comment: revtex4 18 pp., 12 figure

Measurement of the Deuteron Structure Function F2 in the Resonance Region and Evaluation of Its Moments

Inclusive electron scattering off the deuteron has been measured to extract the deuteron structure function F2 with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The measurement covers the entire resonance region from the quasi-elastic peak up to the invariant mass of the final-state hadronic system W~2.7 GeV with four-momentum transfers Q2 from 0.4 to 6 (GeV/c)^2. These data are complementary to previous measurements of the proton structure function F2 and cover a similar two-dimensional region of Q2 and Bjorken variable x. Determination of the deuteron F2 over a large x interval including the quasi-elastic peak as a function of Q2, together with the other world data, permit a direct evaluation of the structure function moments for the first time. By fitting the Q2 evolution of these moments with an OPE-based twist expansion we have obtained a separation of the leading twist and higher twist terms. The observed Q2 behaviour of the higher twist contribution suggests a partial cancellation of different higher twists entering into the expansion with opposite signs. This cancellation, found also in the proton moments, is a manifestation of the "duality" phenomenon in the F2 structure function