Momentum and Coordinate Space Three-nucleon Potentials

In this paper we give explicit formulae in momentum and coordinate space for the three-nucleon potentials due to $\rho$ and $\pi$ meson exchange, derived from off-mass-shell meson-nucleon scattering amplitudes which are constrained by the symmetries of QCD and by the experimental data. Those potentials have already been applied to nuclear matter calculations. Here we display additional terms which appear to be the most important for nuclear structure. The potentials are decomposed in a way that separates the contributions of different physical mechanisms involved in the meson-nucleon amplitudes. The same type of decomposition is presented for the $\pi - \pi$ TM force: the $\Delta$, the chiral symmetry breaking and the nucleon pair terms are isolated.Comment: LATEX, 33 pages, 3 figures (available as postscript files upon request

Off-Mass-Shell π\piN Scattering and pp→ppπ0pp \to pp \pi^0

We adapt the off-shell $\pi$N amplitude of the Tucson-Melbourne three-body force to the half-off-shell amplitude of the pion rescattering contribution to $pp \to pp \pi^0$ near threshold. This {\em pion} rescattering contribution, together with the impulse term, provides a good description of the data when the half-off-shell amplitude is linked to the phenomenological invariant amplitudes obtained from meson factory $\pi$N scattering data.Comment: 3 pages, contributed to STORRI99, Bloomington, Indiana, September 199

Does The 3N-Force Have A Hard Core?

The meson-nucleon dynamics that generates the hard core of the RuhrPot two-nucleon interaction is shown to vanish in the irreducible 3N force. This result indicates a small 3N force dominated by conventional light meson-exchange dynamics and holds for an arbitrary meson-theoretic Lagrangian. The resulting RuhrPot 3N force is defined in the appendix. A completely different result is expected when the Tamm-Dancoff/Bloch-Horowitz procedure is used to define the NN and 3N potentials. In that approach, (e.g. full Bonn potential) both the NN {\it and} 3N potentials contain non-vanishing contributions from the coherent sum of meson-recoil dynamics and the possibility of a large hard core requiring explicit calculation cannot be ruled out.Comment: 16 pages REVTeX + 3 ps fig

Definition of valid proteomic biomarkers: a bayesian solution

Clinical proteomics is suffering from high hopes generated by reports on apparent biomarkers, most of which could not be later substantiated via validation. This has brought into focus the need for improved methods of finding a panel of clearly defined biomarkers. To examine this problem, urinary proteome data was collected from healthy adult males and females, and analysed to find biomarkers that differentiated between genders. We believe that models that incorporate sparsity in terms of variables are desirable for biomarker selection, as proteomics data typically contains a huge number of variables (peptides) and few samples making the selection process potentially unstable. This suggests the application of a two-level hierarchical Bayesian probit regression model for variable selection which assumes a prior that favours sparseness. The classification performance of this method is shown to improve that of the Probabilistic K-Nearest Neighbour model

Triton calculations with π\pi and ρ\rho exchange three-nucleon forces

The Faddeev equations are solved in momentum space for the trinucleon bound state with the new Tucson-Melbourne $\pi$ and $\rho$ exchange three-nucleon potentials. The three-nucleon potentials are combined with a variety of realistic two-nucleon potentials. The dependence of the triton binding energy on the $\pi NN$ cut-off parameter in the three-nucleon potentials is studied and found to be reduced compared to the case with pure $\pi$ exchange. The $\rho$ exchange parts of the three-nucleon potential yield an overall repulsive effect. When the recommended parameters are employed, the calculated triton binding energy turns out to be very close to its experimental value. Expectation values of various components of the three-nucleon potential are given to illustrate their significance for binding.Comment: 17 pages Revtex 3.0, 4 figures. Accepted for publication in Phys. Rev.

Benchmark calculations for polarization observables in 3N scattering

High precision benchmark calculations for phase-shifts and mixing parameters as well as observables in elastic neutron-deuteron scattering below the deuteron breakup threshold are presented using a realistic nucleon-nucleon potential. Two totally different methods, one using a variational principle in configuration space and the other solving the Faddeev equations in momentum space are used and compared to each other. The agreement achieved in phase-shifts and mixing parameters as well as in the polarization observables is excellent. The extreme sensitivity of the vector analyzing power Ay to small changes of the phase shifts and mixing parameters is pointed out.Comment: 22 pages, 5 postscript figure

ΔI=1\Delta I=1 axial-vector mixing and charge symmetry breaking

Phenomenological Lagrangians that exhibit (broken) chiral symmetry as well as isospin violation suggest short-range charge symmetry breaking (CSB) nucleon-nucleon potentials with a \mbox{\boldmath \sigma}_1 \!\cdot\!\mbox{\boldmath \sigma}_2 structure. This structure could be realized by the mixing of axial-vector ($1^+$) mesons in a single-meson exchange picture. The Coleman-Glashow scheme for $\Delta I_{z}=1$ charge symmetry breaking applied to meson and baryon $SU(2)$ mass splittings suggests a universal scale. This scale can be extended to $\Delta I=1$ nonstrange CSB transitions $\langle a_1^\circ|H_{em}|f_1\rangle$ of size $-0.005$ GeV$^2$. The resulting nucleon-nucleon axial-vector meson exchange CSB potential then predicts $\Delta I=1$ effects which are small.Comment: 14 pages. To appear in Phys. Lett.

Analyzing power in nucleon-deuteron scattering and three-nucleon forces

Three-nucleon forces have been considered to be one possibility to resolve the well known discrepancy between experimental values and theoretical calculations of the nucleon analyzing power in low energy nucleon-deuteron scattering. In this paper, we investigate possible effects of two-pion exchange three-nucleon forces on the analyzing power and the differential cross section. We found that the reason for different effects on the analyzing power by different three-nucleon forces found in previous calculations is related to the existence of the contact term. Effects of some variations of two-pion exchange three-nucleon forces are investigated. Also, an expression for the measure of the nucleon analyzing power with quartet P-wave phase shifts is presented.Comment: 11 pages including 2 eps figures, use epsfig.sty, to appear in Phys. Rev.

Experiences of the ‘Nearest Relative’ provisions in the compulsory detention of people under the Mental Health Act: rapid systematic review

This is the final version. Available from NIHR Journals Library via the DOI in this record.Background Service users detained for assessment and/or treatment under the Mental Health Act 1983 are allocated a ‘Nearest Relative’. The Nearest Relative has access to confidential information about the service user, and can make decisions about their care and treatment. Tensions exist regarding the identification, displacement and powers of the Nearest Relative. Objectives To examine the experiences of service users, carers and relevant professionals of the Nearest Relative provisions of the Mental Health Act 1983, and the equivalent Named Person provisions in Scotland. Five research objectives were defined, understanding the experiences of and issues associated with i) identification of the Nearest Relative, ii) displacement of the Nearest Relative, iii) confidentiality and information sharing iv) access to support from carers and v) making decisions about treatment or care. Data sources Seven bibliographic databases: MEDLINE (via Ovid), MEDLINE In-Process & Other Non-Indexed Citations (via Ovid), PsycINFO (via Ovid), Social Policy and Practice (via Ovid), HMIC (via Ovid), CINAHL (via EBSCO) and ASSIA (via ProQuest). Citation searching, author contact and grey literature searches were conducted. Review methods A rapid systematic review was conducted in six weeks. Evidence published after 1998 was sought from the UK, pertaining to the experiences of those involved in compulsory detention under the Mental Health Act 1983 (or UK variants), including service users, carers, family members, Nearest Relatives, Named Persons, mental health professionals, policy makers and lawyers. Study selection, data extraction and critical appraisal were completed independently by two reviewers. We sought data about experiences obtained through qualitative means or surveys. Included studies containing several paragraphs of participant quotes and/or author interpretations were entered into a framework synthesis; the rest were summarised descriptively. The framework synthesis was based upon the five research objectives and refined using the findings of key studies from England and Scotland and inductive thematic analysis. Findings Twenty studies were included with 12 prioritised for framework synthesis. Four themes emerged i) issues regarding the identification of the Nearest Relative/Named Person, ii) confidentiality and information sharing, iii) enabling use of the Nearest Relative/Named Person role and iv) importance of maintaining relationships. The involvement of service users in choosing their representative and the role of services in supporting the Nearest Relative/Named Person was identified as important. Limitations There is little recent evidence to inform this important and complex discussion. The review was rigorously conducted despite the short timescale; however a more in-depth, iterative thematic analysis of all the included studies may have provided additional insights into the mechanisms underpinning the issues. Conclusions The Nearest Relative provisions of the Mental Health Act 1983 are complex and of significant importance to individuals detained under the Act and their carers. This rapid review provides specific examples of issues that individuals may experience. More research is needed to aid understanding of this complex topic. Future work Primary research specifically focussed on the perceived and actual use and impact of the Nearest Relative provisions in England and Scotland.This report was commissioned by the Department of Health and Social Care via the NIHR HS&DR programme as a review project within NIHR HS&DR programme project number 16/47/22

Medicago PhosphoProtein Database: a repository for Medicago truncatula phosphoprotein data

The ability of legume crops to fix atmospheric nitrogen via a symbiotic association with soil rhizobia makes them an essential component of many agricultural systems. Initiation of this symbiosis requires protein phosphorylation-mediated signaling in response to rhizobial signals named Nod factors. Medicago truncatula (Medicago) is the model system for studying legume biology, making the study of its phosphoproteome essential. Here, we describe the Medicago PhosphoProtein Database (MPPD; http://phospho.medicago.wisc.edu), a repository built to house phosphoprotein, phosphopeptide, and phosphosite data specific to Medicago. Currently, the MPPD holds 3,457 unique phosphopeptides that contain 3,404 non-redundant sites of phosphorylation on 829 proteins. Through the web-based interface, users are allowed to browse identified proteins or search for proteins of interest. Furthermore, we allow users to conduct BLAST searches of the database using both peptide sequences and phosphorylation motifs as queries. The data contained within the database are available for download to be investigated at the user’s discretion. The MPPD will be updated continually with novel phosphoprotein and phosphopeptide identifications, with the intent of constructing an unparalleled compendium of large-scale Medicago phosphorylation data