Analyzing the Fierz Rearrangement Freedom for Local Chiral Two-Nucleon Potentials

Chiral effective field theory is a framework to derive systematic nuclear interactions. It is based on the symmetries of quantum chromodynamics and includes long-range pion physics explicitly, while shorter-range physics is expanded in a general operator basis. The number of low-energy couplings at a particular order in the expansion can be reduced by exploiting the fact that nucleons are fermions and therefore obey the Pauli exclusion principle. The antisymmetry permits the selection of a subset of the allowed contact operators at a given order. When local regulators are used for these short-range interactions, however, this "Fierz rearrangement freedom" is violated. In this paper, we investigate the impact of this violation at leading order (LO) in the chiral expansion. We construct LO and next-to-leading order (NLO) potentials for all possible LO-operator pairs and study their reproduction of phase shifts, the ${}^4$He ground-state energy, and the neutron-matter energy at different densities. We demonstrate that the Fierz rearrangement freedom is partially restored at NLO where subleading contact interactions enter. We also discuss implications for local chiral three-nucleon interactions.Comment: 11 pages, 5 figure

Xwnt-5A: a maternal Wnt that affects morphogenetic movements after overexpression in embryos of Xenopus laevis

To contribute to an understanding of the roles and mechanisms of action of Wnts in early vertebrate development, we have characterized the normal expression of Xenopus laevis Wnt-5A, and investigated the consequences of misexpression of this putative signalling factor. Xwnt-5A transcripts are expressed throughout development, and are enriched in both the anterior and posterior regions of embryos at late stages of development, where they are found primarily in ectoderm, with lower levels of expression in mesoderm. Overexpression of Xwnt-5A in Xenopus embryos leads to complex malformations distinct from those achieved by ectopic expression of Xwnts −1, −3A, or −8. This phenotype is unlikely to result from Xwnt-5A acting as an inducing agent, as overexpression of Xwnt-5A does not rescue dorsal structures in UV-irradiated embryos, does not induce mesoderm in blastula caps, and Xwnt-5A does not alter the endogenous patterns of expression of goosecoid, Xbra, or Xwnt-8. To pursue whether Xwnt-5A has the capacity to affect morphogenetic movements, we investigated whether overexpression of Xwnt-5A alters the normal elongation of blastula cap explants induced by activin. Intriguingly, Xwnt-5A blocks the elongation of blastula caps in response to activin, without blocking the differentiation of either dorsal or ventral mesoderm within these explants. The data are consistent with Xwnt-5A having the potential activity of modifying the morphogenetic movements of tissues

Antiferromagnetic Order of the Ru and Gd in Superconducting RuSr2GdCu2O8

Neutron diffraction has been used to study the magnetic order in RuSr{2}GdCu2O8. The Ru moments order antiferromagnetically at T{N}=136(2)K, coincident with the previously reported onset of ferromagnetism. Neighboring spins are antiparallel in all three directions, with a low T moment of 1.18(6) mu {B} along the c-axis. Our measurements put an upper limit of ~0.1 mu{B} to any net zero-field moment, with fields exceeding ~0.4T needed to induce a measurable magnetization. The Gd ions order independently at T{N}=2.50(2)K with the same spin configuration. PACS numbers: 74.72.Jt, 75.25.+z, 74.25.Ha, 75.30.KzComment: Four pages, Latex, 5 eps figure

Dose-dependent effects of a soluble dietary fibre (pectin) on food intake, adiposity, gut hypertrophy and gut satiety hormone secretion in rats

Acknowledgments We thank Donna Wallace and Animal House staff at the Rowett Institute of Nutrition and Health for the daily care of experimental rats and for the body weight, food intake and MRI measurements.Peer reviewedPublisher PD

Pharyngeal Lymphoid Hyperplasia

Pharyngeal lymphoid hyperplasia (PLH) is a condition in horses involving proliferation of one of the equine tonsillar structures. It has been diagnosed more frequently in the past few years due to a greater awareness of its existence, a developing prevalence of endoscopic examination, and/or an increased incidence of the syndrome

DYNAMIC RELATIONSHIPS: E-COMMERCE SALES AND KEY EXOGENOUS VARIABLES IN THE PHILIPPINES

This study delves into the complex and evolving landscape of e-commerce in the Philippines, focusing on the relationship between E-Commerce Sales as the endogenous variable and a set of influential exogenous variables, including Digital Marketing Spending, GDP Growth, Internet Penetration, and Mobile Phone Ownership. This research employs a flexible spline modeling approach, uncovers non-linear associations, and offers significant implications for academic understanding and practical applications. The findings underscore the growing impact of Digital Marketing Spending on E-Commerce Sales, revealing the paramount role of online advertising and promotional strategies in the digital marketplace. Moreover, the study explains the intricate interplay between GDP Growth, Internet Penetration, Mobile Phone Ownership, and E-Commerce Sales, highlighting the non-linear nature of these relationships. As the Philippines continues its economic expansion and technological integration, these associations exhibit insightful implications for policymakers, businesses, and e-commerce stakeholders.  Article visualizations

Seeing What Others Miss: A Study of Women Entrepreneurs in High-Growth Startups

A pressing question in entrepreneurial research is where opportunities come from. Prior research indicates that some opportunities stem from known parameters and outcomes; some are discovered through engagement with unknown but knowable factors; and others are unknowable until brought into being through a creative process. This paper explores the second and more prevailing view in entrepreneurial research – that individuals discover business opportunity – and examines how high-growth entrepreneurs perceive opportunity through engagement with the world. Survey results, based on responses from 165 women entrepreneurs in high-growth startups, indicate that individuals with a strong discover mindset act and think in ways that support opportunity perception. Coupled with a belief in her abilities, the entrepreneur is more likely to move from opportunity perception to new venture creation. Results from semi-structured interviews with women from the same population elucidate the survey findings and yield implications for entrepreneurial theory and practice

Dust devils on Earth and Mars: Extension of particle threshold laboratory simulations

Abstract not available

Chaotic Scattering in the Regime of Weakly Overlapping Resonances

We measure the transmission and reflection amplitudes of microwaves in a resonator coupled to two antennas at room temperature in the regime of weakly overlapping resonances and in a frequency range of 3 to 16 GHz. Below 10.1 GHz the resonator simulates a chaotic quantum system. The distribution of the elements of the scattering matrix S is not Gaussian. The Fourier coefficients of S are used for a best fit of the autocorrelation function if S to a theoretical expression based on random--matrix theory. We find very good agreement below but not above 10.1 GHz