Partial-wave analysis is an important tool for analyzing large data sets in hadronic decays of light and heavy mesons. It commonly relies on the isobar model, which assumes multihadron final states ...originate from successive two-body decays of well-known undisturbed intermediate states. Recently, analyses of heavy-meson decays and diffractively produced states have attempted to overcome the strong model dependences of the isobar model. These analyses have overlooked that model-independent, or freed-isobar, partial-wave analysis can introduce mathematical ambiguities in results. We show how these ambiguities arise and present general techniques for identifying their presence and for correcting for them. We demonstrate these techniques with specific examples in both heavy-meson decay and pion–proton scattering.
Abstract
Objective:
Larch arabinogalactan (ResistAid*) may prevent cold infections due to its immune-stimulatory properties. In a placebo-controlled, double-blind, randomized clinical trial, the ...effect of a proprietary larch arabinogalactan preparation on the incidences of common colds and its effect on cold symptoms, as a well established model for immune function, was compared to placebo.
Research design and methods:
A total of 199 healthy participants who had a self reported cold infection rate of three in 6 months were randomly assigned to receive a total of either 4.5 g of an arabinogalactan preparation (n = 101) or placebo (n = 98) over a period of 12 weeks.
Main outcome measures:
The participants documented each common cold episode in a diary, and rated 10 predefined infection symptoms on a 4 point rating scale during an infection period, resulting in an infection score. The common cold episodes were confirmed by medical doctors.
Clinical trial registration:
ISRCTN41183655.
Results:
In the full analysis set (FAS), arabinogalactan tended to decrease the incidence of common cold (p = 0.055). The number of participants affected by a cold was significantly reduced by arabinogalactan supplementation (p = 0.038). Concerning the per protocol (PP) collective, the incidences of common cold (p = 0.040) and the number of participants affected by the infection (p = 0.033) were significantly fewer after arabinogalactan compared to placebo consumption. The severity of symptoms at episode start as experienced by the participants was significantly higher after arabinogalactan supplementation (p = 0.028). The treatment was well tolerated with no significant differences between the study groups.
Conclusion:
The present study demonstrated that larch arabinogalactan increased the body's potential to defend against common cold infection. While the immunomodulatory effect of arabinogalactan can be assumed, its mechanism of action remains to be elucidated.
Light-meson spectroscopy with COMPASS Ketzer, B.; Grube, B.; Ryabchikov, D.
Progress in particle and nuclear physics,
July 2020, 2020-07-00, Letnik:
113
Journal Article
Recenzirano
Odprti dostop
Despite decades of research, we still lack a detailed quantitative understanding of the way quantum chromodynamics (QCD) generates the spectrum of hadrons. Precise experimental studies of the hadron ...excitation spectrum and the dynamics of hadrons help to improve models and to test effective theories and lattice QCD simulations. In addition, QCD seems to allow hadrons beyond the three-quark and quark–antiquark configurations of the constituent-quark model. These so-called exotic hadrons contain additional constituent (anti)quarks or excited gluonic fields that contribute to the quantum numbers of the hadron. Hadron spectroscopy is currently one of the most active fields of research in hadron physics. The COMPASS experiment at the CERN SPS is studying the excitation spectrum of light mesons, which are composed of up, down, and strange quarks. The excited mesons are produced via the strong interaction, i.e. by Pomeron exchange, by scattering a 190GeV/c pion beam off proton or nuclear targets. On heavy nuclear targets, in addition the electromagnetic interaction contributes in the form of quasi-real photon exchange at very low four-momentum transfer squared. COMPASS has performed the most comprehensive analyses to date of isovector resonances decaying into ηπ, η′π, or π−π−π+ final states. In this review, we give a general and pedagogical introduction into scattering theory and the employed partial-wave analysis techniques. We also describe novel methods developed for the high-precision COMPASS data. The COMPASS results are summarized and compared to previous measurements. In addition, we discuss possible signals for exotic mesons and conclude that COMPASS data provide solid evidence for the existence of the manifestly exotic π1(1600), which has quantum numbers forbidden for a quark-model state, and of the a1(1420), which does not fit into the quark-model spectrum. By isolating the contributions from quasi-real photon exchange, COMPASS has measured the radiative widths of the a2(1320) and, for the first time, that of the π2(1670) and has tested predictions of chiral perturbation theory for the process π−+γ→π−π−π+.
This randomised, double-blind, bicenter, placebo-controlled clinical trial investigated the effect of a daily application of 6
g Kytta-Salbe
® f (3×2
g) over a 3 week period with patients suffering ...from painful osteoarthritis of the knee.
The two hundred and twenty patients examined consisted of 153 women and 67 men of an average age of 57.9 years. On average, the complaints relating to osteoarthritis of the knee had persisted for 6.5 years. Two hundred and twenty patients were included in the Full Analysis Set (FAS) and safety collective, 186 (84.5%) in the Valid Case Analysis Set (VCAS) collective.
In the course of the trial, the visual analog scale (VAS) total score (primary target value) in the verum group dropped by 51.6
mm (54.7%) and in the placebo group by 10.1
mm (10.7%). The average difference between the groups of 41.5
mm (95% confidence interval=34.8 to 48.2
mm) or 44.0% is significant (
p<0.001). The significance is confirmed through the evaluation of the diary, the VCAS evaluation and the separate assessment of the two centres. This also applies to the separate assessment of the VAS total score following pain at rest and on movement.
The WOMAC (Western Ontario and McMaster Universities) total score (secondary target value) also improved similar to the VAS total score. At the end of the trial, a reduction by 60.4
mm (58.0%) was recorded for the verum group and a reduction of 14.7
mm (14.1%) for the placebo group. The average group difference of 45.7
mm (95% confidence interval=37.1 to 54.3
mm) or 43.9% is significant (
p<0.001).
The difference between the treatment groups increased systematically and significantly, in parallel with the duration of the treatment. Thus, the superiority of the treatment with Kytta-Salbe
® f over that with the placebo is proven, even by means of the multi-factorial multivariate analysis for repetitive measurements.
In respect of the explorative secondary target values SF-36 (quality of life), angle measurement (mobility of the knee), CGI (clinical global impression) and global assessment of efficacy by the physician and the patient, a significant superiority (
p<0.001 each) of the verum group over the placebo group was also proven.
The results suggest that the comfrey root extract ointment is well suited for the treatment of osteoarthritis of the knee. Pain is reduced, mobility of the knee improved and quality of life increased.
Estrogen is a major factor in the development of breast cancer. In situ estrogen production by aromatase/estrogen synthetase in breast cancer plays a dominant role in tumor proliferation. Because ...natural compounds such as flavones and isoflavones have been shown to be inhibitors of aromatase, it is thought that vegetables that contain these phytochemicals can inhibit aromatase activity and suppress breast cancer cell proliferation. Heat-stable extracts were prepared from vegetables and screened for their ability to inhibit aromatase activity in a human placental microsome assay. The white button mushroom (species Agaricus bisporus) suppressed aromatase activity dose dependently. Enzyme kinetics demonstrated mixed inhibition, suggesting the presence of multiple inhibitors or more than one inhibitory mechanism. “In cell” aromatase activity and cell proliferation were measured using MCF-7aro, an aromatase-transfected breast cancer cell line. Phytochemicals in the mushroom aqueous extract inhibited aromatase activity and proliferation of MCF-7aro cells. These results suggest that diets high in mushrooms may modulate the aromatase activity and function in chemoprevention in postmenopausal women by reducing the in situ production of estrogen.
Factor and correlational analyses have been used to characterize symptom dimensions in schizophrenia, though they have yielded divergent models. This study used meta-analysis of published work to ...determine the number and composition of symptom dimensions. Principal components analysis of data from 10 empirical studies (pooled
n = 896) yielded three factors, ‘positive’, ‘negative’ and ‘conceptual disorganization’. The findings suggest that a three-factor solution is a relatively stable outcome of studies assessing these symptoms in chronic patients, and that some symptoms (alogia, attentional impairment) are less likely to load uniquely on a single factor.
We present first results of a partial wave analysis of the diffractive reaction π− Pb → π− π+ π− Pb based on data from the COMPASS experiment taken during a pilot run in 2004 using a 190 GeV/c π− beam ...on a lead target. The analysis was performed in the region of squared four-momentum transfer t' between 0.1 and 1.0 (GeV/c)2 . The π− π+ π− final state shows a rich spectrum of well-known resonances. In addition a spin-exotic JPC = 1−+ state with significant intensity was observed at 1.66 GeV/c2 in the ρ(770) π decay channel in natural parity exchange. The resonant nature of this state is manifest in the mass dependence of its phase difference to JPC = 1++ and 2−+ waves. The measured resonance parameters are consistent with the disputed π1 (1600). An outlook on the analyses of the much larger data set taken during 2008 and 2009 is given.
A data acquisition system for a positron emission tomograph (PET) based on avalanche photodiode (APD) readout of lutetium oxyorthosilicate (LSO) scintillator crystals is presented. The analog data of ...each APD are read out by fast analog to digital converters (ADCs) and processed within field programmable gate arrays (FPGAs). The ADCs are continuously sampling with a 80 MHz, low jitter clock, which is synchronous for the whole detector. The main tasks of the FPGAs are pulse detection and extraction of signal timing information from the digitized data stream. The detected signal pulse data are therefore compared to a predefined set of pulse shapes with known phase shifts with respect to the sample clock. By searching for the best match within this calibration set, a precise start time information for the signal pulse can be determined. The calculated time values are then transmitted from the ADC cards via fiber optic links to multiplexer modules which combine the different data streams and can also perform further processing like search for coincident events. Finally, the preprocessed detector data are transmitted from the multiplexers to PCI cards in the image reconstruction computers by gigabit optical links
PDF
