Phys. Rev. C 98, 015207 (2018) Exclusive photoproduction cross sections have been measured for the process
$\gamma p \rightarrow p\pi^0(e^+e^-(\gamma))$ with the Dalitz decay final state
using tagged ...photon energies in the range of $E_{\gamma} = 1.275-5.425$ GeV.
The complete angular distribution of the final state $\pi^0$, for the entire
photon energy range up to large values of $t$ and $u$, has been measured for
the first time. The data obtained show that the cross section $d\sigma/dt$, at
mid to large angles, decreases with energy as $s^{-6.89\pm 0.26} $. This is in
agreement with the perturbative QCD quark counting rule prediction of $s^{-7}
$. Paradoxically, the size of angular distribution of measured cross sections
is greatly underestimated by the QCD based Generalized Parton Distribution
mechanism at highest available invariant energy $s=11$ GeV$^2$. At the same
time, the Regge exchange based models for $\pi^0$ photoproduction are more
consistent with experimental data.
Summary Background Children with HIV will be on antiretroviral therapy (ART) longer than adults, and therefore the durability of first-line ART and timing of switch to second-line are key questions. ...We assess the long-term outcome of protease inhibitor and non-nucleoside reverse transcriptase inhibitor (NNRTI) first-line ART and viral load switch criteria in children. Methods In a randomised open-label factorial trial, we compared effectiveness of two nucleoside reverse transcriptase inhibitors (NRTIs) plus a protease inhibitor versus two NRTIs plus an NNRTI and of switch to second-line ART at a viral load of 1000 copies per mL versus 30 000 copies per mL in previously untreated children infected with HIV from Europe and North and South America. Random assignment was by computer-generated sequentially numbered lists stratified by age, region, and by exposure to perinatal ART. Primary outcome was change in viral load between baseline and 4 years. Analysis was by intention to treat, which we defined as all patients that started treatment. This study is registered with ISRCTN, number ISRCTN73318385. Findings Between Sept 25, 2002, and Sept 7, 2005, 266 children (median age 6·5 years; IQR 2·8–12·9) were randomly assigned treatment regimens: 66 to receive protease inhibitor and switch to second-line at 1000 copies per mL (PI-low), 65 protease inhibitor and switch at 30 000 copies per mL (PI-higher), 68 NNRTI and switch at 1000 copies per mL (NNRTI-low), and 67 NNRTI and switch at 30 000 copies per mL (NNRTI-higher). Median follow-up was 5·0 years (IQR 4·2–6·0) and 188 (71%) children were on first-line ART at trial end. At 4 years, mean reductions in viral load were −3·16 log10 copies per mL for protease inhibitors versus −3·31 log10 copies per mL for NNRTIs (difference −0·15 log10 copies per mL, 95% CI −0·41 to 0·11; p=0·26), and −3·26 log10 copies per mL for switching at the low versus −3·20 log10 copies per mL for switching at the higher threshold (difference 0·06 log10 copies per mL, 95% CI −0·20 to 0·32; p=0·56). Protease inhibitor resistance was uncommon and there was no increase in NRTI resistance in the PI-higher compared with the PI-low group. NNRTI resistance was selected early, and about 10% more children accumulated NRTI mutations in the NNRTI-higher than the NNRTI-low group. Nine children had new CDC stage-C events and 60 had grade 3/4 adverse events; both were balanced across randomised groups. Interpretation Good long-term outcomes were achieved with all treatments strategies. Delayed switching of protease-inhibitor-based ART might be reasonable where future drug options are limited, because the risk of selecting for NRTI and protease-inhibitor resistance is low. Funding Paediatric European Network for Treatment of AIDS (PENTA) and Pediatric AIDS Clinical Trials Group (PACTG/IMPAACT).
The Soil and Water Assessment Tool (SWAT) is an ecohydrological watershed-scale model which was initially developed in the early 1990s to simulate the impacts of land use, management systems, and ...climate on hydrology and/or water quality. First adopted in the U.S., the use of the model then spread to Europe and then later to Asia and other regions. The range of applications that SWAT has been applied to have also expanded dramatically, which influenced ongoing model development which has been virtually continuous over the past two decades. A key component of many SWAT applications in Asia is accounting for rice paddy production that is common in some subregions within the continent. However, most of these studies do not provide explicit details of how rice production was simulated in SWAT. Other research has revealed that significant problems occur when trying to represent rice paddy systems in standard versions of SWAT, due to limitations in algorithms based on the runoff curve number approach or the pothole option. In response, key modifications have been made to SWAT in recent studies that have resulted in a more accurate representation of rice paddy systems. These developments point to the need for the incorporation of an enhanced rice paddy module within SWAT to better capture rice paddy hydrological and pollutant dynamics, which would support improved use of the model in Asia and other rice production regions. Subtopics related to simulating rice production in SWAT are discussed as follows: 1) an overview of global rice production; 2) history of SWAT development; 3) typical approaches for simulating rice production; 4) problems associated with the typical approaches; 5) recent code modifications to address deficiencies in replicating rice paddy systems; 6) recommendations for developing a standard rice paddy module for future SWAT codes.
Zeitschrift für Kristallographie. Supplement Volume 23 presents the complete Proceedings of all contributions to the IX European Powder Diffraction Conference in Prague 2004: Method Development and ...Application, Instrumental, Software Development, Materials Supplement Series of Zeitschrift für Kristallographie publishes Proceedings and Abstracts of international conferences on the interdisciplinary field of crystallography.
We have used the Habitable Zone Planet Finder (HPF) to gather high resolution, high signal-to-noise near-infrared spectra of 13 field red horizontal-branch (RHB) stars, one open-cluster giant, and ...one very metal-poor halo red giant. The HPF spectra cover the 0.81\(-\)1.28 \micron\ wavelength range of the \(zyJ\) bands, filling in the gap between the optical (0.4\(-\)1.0~\micron) and infrared (1.5\(-\)2.4~\micron) spectra already available for the program stars. We derive abundances of 17 species from LTE-based computations involving equivalent widths and spectrum syntheses, and estimate abundance corrections for the species that are most affected by departures from LTE in RHB stars. Generally good agreement is found between HPF-based metallicities and abundance ratios and those from the optical and infrared spectral regions. Light element transitions dominate the HPF spectra of these red giants, and HPF data can be used to derive abundances from species with poor or no representation in optical spectra (\eg, \species{C}{i}, \species{P}{i}, \species{S}{i}, \species{K}{i}). Attention is drawn to the HPF abundances in two field solar-metallicity RHB stars of special interest: one with an extreme carbon isotope ratio, and one with a rare very large lithium content. The latter star is unique in our sample by exhibiting very strong \species{He}{i} 10830~\AA\ absorption. The abundances of the open cluster giant concur with those derived from other wavelength regions. Detections of \species{C}{i} and \species{S}{i} in HD~122563 are reported, yielding the lowest metallicity determination of S/Fe from more than one multiplet.
We use 772\(\times 10^6\) \(B \bar{B}\) meson pairs collected at the \(\Upsilon(4S)\) resonance with the Belle detector to measure the branching fraction for \(\bar{B} \rightarrow X_s \gamma\). Our ...measurement uses a sum-of-exclusives approach in which 38 of the hadronic final states with strangeness equal to \(+1\), denoted by \(X_s\), are reconstructed. The inclusive branching fraction for \(M_{X_s}<\) 2.8 GeV/\(c^2\), which corresponds to a minimum photon energy of 1.9 GeV, is measured to be \({\cal B}(\bar{B} \rightarrow X_s \gamma)=(3.51\pm0.17\pm0.33)\times10^{-4}\), where the first uncertainty is statistical and the second is systematic.
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