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The quasifree γ → d → π 0 n (p) photon beam asymmetry, Σ , has been measured at photon energies, E γ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 ∘ to 148 ∘ . In this kinematic region, polarization observables are sensitive to contributions from the Δ (1232) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn–Gatchina analyses; while a revised SAID fit, including the new Σ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict π 0 n photoproduction observables, based on fits to published data in the channels π 0 p , π + n and π - p . [ABSTRACT FROM AUTHOR]

The topical workshop Strong QCD from Hadron Structure Experiments took place at Jefferson Lab from November 6–9, 2019. Impressive progress in relating hadron structure observables to the strong QCD mechanisms has been achieved from the ab initio QCD description of hadron structure in a diverse array of methods in order to expose emergent phenomena via quasi-particle formation. The wealth of experimental data and the advances in hadron structure theory make it possible to gain insight into strong interaction dynamics in the regime of large quark–gluon coupling (the strong QCD regime), which will address the most challenging problems of the Standard Model on the nature of the dominant part of hadron mass, quark–gluon confinement, and the emergence of the ground and excited state hadrons, as well as atomic nuclei, from QCD. This workshop aimed to develop plans and to facilitate the future synergistic efforts between experimentalists, phenomenologists, and theorists working on studies of hadron spectroscopy and structure with the goal to connect the properties of hadrons and atomic nuclei available from data to the strong QCD dynamics underlying their emergence from QCD. These results pave the way for a future breakthrough extension in the studies of QCD with an Electron–Ion Collider in the U.S. [ABSTRACT FROM AUTHOR]

Many physiological and ecological processes depend on body size and the supply of limiting nutrients. Hence, it is important to derive quantitative predictions based on a mechanistic understanding of the influence of body size on metabolic rate and on the ratios of consumed to excreted elements. Among diverse pelagic invertebrates that change shape during ontogeny, recent analysis has demonstrated a significant positive correlation between the body-mass allometry of respiration rates (measured as the ontogenetic body mass-scaling exponent bR) and the allometry of body surface area ( bA, as predicted from body-shape changes using a Euclidean model). As many pelagic invertebrates use a large portion of their external body surface for both resource uptake and waste excretion, we predicted that body-mass scaling exponents for rates of excretion of soluble N ( bN) should also then relate to the degree of body-shape change during growth. We tested this hypothesis using literature data on bN for 39 species of pelagic invertebrates across five different phyla, and find strong support: bN is significantly positively correlated with predicted bA, whilst also co-varying with bR. Intraspecific differences between bN and bR values reveal ontogenetic shifts in the ratio of O2-consumed to N-excreted. We suggest that a variety of factors, including adaptive developmental shifts in the relative anabolism and catabolism of proteins and lipids, may cause these shifts in consumption-excretion ratios. Diverse pelagic invertebrates that dominate vast open water ecosystems falsify the predictions of general metabolic scaling theories built upon resource-transport networks, but support predictions of surface-area dependent theory. [ABSTRACT FROM AUTHOR]

Although isopod crustaceans frequently show sexual dimorphism in body size, sexual differences in other non-reproductive (secondary sexual) traits have been rarely studied. Furthermore, little is known about the physiological correlates of variation in the expression of sexually dimorphic traits in animals generally. Here, we show that the unusual dorsal horns of the South African horned isopod Deto echinata exhibit significantly different allometric scaling relationships with body size in males versus females. Not only are the horns of adult males substantially longer than those of adult females but also their log-log scaling slope with body length is significantly steeper than that of females and juveniles. Furthermore, in males relative horn length is positively correlated with body condition, as estimated by body mass relative to body length, and with resting metabolic ( CO2 release) rate, also adjusted to body length. However, although showing a weak positive trend, the relative horn length of males is not significantly correlated with body length adjusted active metabolic rate. It is also not significantly correlated with the relative rates of whole body or cuticular water loss rates or with two measures of activity level. We hypothesize that the sexual dimorphism of horn length in D. echinata is the result of sexual selection and that horn length is a reliable indicator of the ability of a male to acquire and process resources, which in turn may be critical to female mate choice and (or) male-male competition for mates. However, this hypothesis requires further testing based on direct observations of female mate choice and male-male behavioral interactions, which have not yet been carried out. [ABSTRACT FROM AUTHOR]

Quasi-free photoproduction of $\pi\eta$ -pairs has been investigated from threshold up to incident photon energies of 1.4 GeV, respectively up to photon-nucleon invariant masses up to 1.9 GeV. Total cross sections, angular distributions, invariant-mass distributions of the $ \pi\eta$ and meson-nucleon pairs, and beam-helicity asymmetries have been measured for the reactions $ \gamma p\rightarrow p\pi^{0}\eta$ , $ \gamma n\rightarrow n\pi^{0}\eta$ , $ \gamma p\rightarrow n\pi^{+}\eta$ , and $\gamma n\rightarrow p\pi^{-}\eta$ from nucleons bound inside the deuteron. For the $\gamma p$ initial-state data for free protons have also been analyzed. Finally, the total cross sections for quasi-free production of $ \pi^{0}\eta$ pairs from nucleons bound in He nuclei have been investigated in view of final state interaction (FSI) effects. The experiments were performed at the tagged photon beam facility of the Mainz MAMI accelerator using an almost 4 $ \pi$ covering electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. The shapes of all differential cross section data and the asymmetries are very similar for protons and neutrons and agree with the conjecture that the reactions are dominated by the sequential $ \Delta^{\star}3/2^{-}\rightarrow \eta\Delta(1232) \rightarrow\pi\eta N$ decay chain, mainly with $ \Delta(1700)3/2^{-}$ and $ \Delta(1940)3/2^{-}$ . The ratios of the magnitude of the total cross sections also agree with this assumption. However, the absolute magnitudes of the cross sections are reduced by FSI effects with respect to free proton data. [ABSTRACT FROM AUTHOR]

The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document. The material presented in the article was edited by the following Editorial Board: Marco Battaglieri, Bill J. Briscoe, Su-Urk Chung, Michael Döring, Józef Dudek, Geoffrey Fox, Christoph Hanhart, Martin Hoferichter, David G. Ireland, Bernhard Ketzer, Bastian Kubis, Vincent Mathieu, Ryan Mitchell, José R. Peláez, Elena Santopinto, Adam Szczepaniak. [ABSTRACT FROM AUTHOR]

In this study, we investigated variation in offspring size (OS) of Daphnia magna in relation to multiple maternal traits and environmental variables. Data originated from laboratory experiments conducted at different feeding scenarios. The mother daphnids had different life-history traits and were reared under various feeding and density conditions. OS showed linear relationships with maternal traits, varying positively with maternal body size, age and brood number, and negatively with brood size and with the amount of ingested carbon. OS increased exponentially with crowding. Using stepwise multiple regression analysis, we developed an empirical model for the OS variation with the relevant maternal and environmental variables. Density dependence was considered by multiplying the resulting model by a density-effect function. We found that the ingested carbon and the maternal body size were the strongest determinants of the observed variation in the OS, whereas the brood size had the least impact on OS. Additionally, the brood number had no significant effect in determining the variability in the OS. The validity of the multivariate model was tested against an independent dataset. The model accurately predicted the OS despite several genetic and environmental differences compared with the data used for parameterization. [ABSTRACT FROM PUBLISHER]

The reaction γp → pπ0γ′ has been measured with the Crystal Ball/TAPS detectors using the energy-tagged photon beam at the electron accelerator facility MAMI-B. Energy and angular differential cross-sections for the emitted photon γ′ and angular differential cross-sections for the π0 have been determined with high statistics in the energy range of the Δ+ (1232)-resonance. Cross-sections and the ratio of the cross-section to the nonradiative process γp → pπ0 are compared to theoretical reaction models, having the anomalous magnetic moment κ Δ as free parameter. As the shape of the experimental distributions is not reproduced in detail by the model calculations, currently no extraction of κ Δ is feasible. [ABSTRACT FROM AUTHOR]

Total and differential cross-sections for the reaction $\ensuremath \gamma p\rightarrow\pi^0\eta p$ have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range $\ensuremath E_{\gamma} = 0.95\mbox{--}1.4$ GeV the reaction is dominated by the excitation and sequential decay of the $\ensuremath \Delta(1700)D_{33}$ -resonance. Angular distributions measured with high statistics allow us to determine the ratio of hadronic decay widths $\ensuremath \Gamma_{\eta\Delta}/\Gamma_{\pi S_{11}}$ and the ratio of the helicity amplitudes $\ensuremath A_{3/2}/A_{1/2}$ for this resonance. [ABSTRACT FROM AUTHOR]

A precise measurement of the Dalitz plot parameter, $ \alpha$ , for the $ \eta$ → 3 $ \pi^{0}_{}$ decay is presented. The experiment was performed with the Crystal Ball and TAPS large-acceptance photon detectors at the tagged photon beam facility of the MAMI-B electron accelerator in Mainz. High statistics of 1.8 · 106 $ \eta$ → 3 $ \pi^{0}_{}$ events were obtained, giving the result $ \alpha$ = - 0.032±0.002stat±0.002syst . [ABSTRACT FROM AUTHOR]

The photoproduction of K+ mesons is an important challenge to recent QCD based chiral perturbation theories in the strange quark sector and is an important constraint on the nucleon excitation spectrum. We present preliminary data from a new high precision measurement using the Crystal Ball detector. The measurement pioneers a new technique for tagging strangeness using detailed cluster analysis in segmented calorimeters which has potential wider application at present and future hadron physics facilities. [ABSTRACT FROM AUTHOR]

This paper reports on measurements of the 3He( e, e′ pp) reaction measured at AmPS and the 3He( e, e′ pn) reaction measured at MAMI. The measurements were performed in similar kinematics to allow a comparison to be made between the cross sections of the two reactions. Results are shown for both reactions together with a comparison for the 3He( e, e′ pp) data with continuum Faddeev calculations. [ABSTRACT FROM AUTHOR]

This paper reports on the first measurement of the 16O(e, e'pn)14N reaction. Data were measured in kinematics centred on a super-parallel geometry at energy and momentum transfers of 215MeV and 316MeV/ c. The experimental resolution was sufficient to distinguish groups of states in the residual nucleus but not good enough to separate individual states. The data show a strong dependence on missing momentum and this dependence appears to be different for two groups of states in the residual nucleus. Theoretical calculations of the reaction using the Pavia code do not reproduce the shape or the magnitude of the data. [ABSTRACT FROM AUTHOR]

Many types of acrosome induction tests require special equipment and reagents that are not available to most clinicians; thus, simpler tests seem desirable. A modified acrosome induction test has been developed that uses basic reagents and a light microscope, which are available in most office settings. A hypoosmotic swelling test and a double stain (Bismark brown and rose Bengal) were combined to evaluate the viable acrosome reaction (AR) among 74 infertile men and 42 control men. The study included 34 infertile males without varicoceles, 20 with nonrepaired varicoceles and 20 with repaired varicoceles. On each test day, a specimen from a fertile donor was run as a control. The spontaneous acrosome reaction was recorded in semen before and after capacitation. The final % viable acrosome reaction equaled the capacitated value minus the spontaneous value for whole semen. The mean % viable AR among the control specimens was 16% with no values less than 10%. This mean value for controls was significantly greater than the mean % viable AR in each patient group. There were no overlaps in the 95% confidence intervals. When the study group was stratified according to normal acrosome induction tests or >10% viable AR, 30 patients had a normal test and 44 had abnormal tests. Six patients with varicoceles and an abnormal acrosome induction test had a varicocelectomy, and 2 (33%) converted their acrosome induction test to normal after at least 6 months of follow-up. Nine patients had in vitro fertilization (IVF), 3 had a poor result, and all had an abnormal acrosome induction test. Six had a good result with IVF and all 6 had a normal acrosome induction test. Thus, the acrosome induction test described in this report may be performed in any office laboratory to detect subtle male factor problems. The results may be helpful for planning IVF, intracytoplasmic sperm injection, or varicocele surgery for infertile men. [ABSTRACT FROM AUTHOR]

Adenocarcinoma of the rete testis is a rare tumor. Histologic diagnosis is difficult, and in the past the tumor may have been incorrectly identified in a number of cases, leading to misleading information on the nature and behavior of this neoplasm. We present the case of a 39-year-old man with a long history of a small left hydrocele, who was lost to follow-up and presented again 2 years later with testicular discomfort. Sonographic findings were consistent with a testicular tumor. Histology confirmed low-grade adenocarcinoma of the rete testis, the first reported tumor of this grade. Previously reported cases of rete testis carcinoma are reviewed. [ABSTRACT FROM AUTHOR]

A correction to the article titled "First measurements of the 16O(e; e0pn)14N reaction" published in the 2006 issue of the European Physical Journal is presented.

Classical life-history theory predicts 'trade-offs' between reproductive and somatic investments. However, empirical studies have shown that intraspecific phenotypic correlations between these two resource investments are often positive or nonsignificant, rather than negative as predicted. The model of Van Noordwijk and De Jong (1986) was proposed to explain these unexpected results. According to their model, positive correlations between reproductive and somatic investments will result if individual variation in resource acquisition exceeds that of resource allocation, whereas negative correlations will result if individual variation in resource allocation exceeds that of resource acquisition. To test this model, I used body storage/condition as an index of somatic investment because it is usually strongly related to level of resource acquisition. I predicted that laboratory studiesshould more often show negative correlations between reproductive and somatic investments than field studies, because individual variation in resource acquisition is expected to be lower in controlled laboratory environments than in variable natural environments. A literature review revealed that correlations between somatic (storage) investment and reproductive investment (estimated as clutch/litter mass, number of offspring per clutch/litter, or number of clutches/litters) among conspecific breeding female animals are more often positive (15 species) or nonsignificant (17 species) than negative (6 species). Moreover, as expected, five of six negative correlations were observed in laboratory studies, whereas 13 of 15 positive correlations were observed in field studies. It is concluded that future empirical and theoretical work on life histories should consider individual variation in both resource acquisition and allocation and the interaction between the two. [ABSTRACT FROM AUTHOR]