Distinguishing Among Strong Decay Models

Two competing models for strong hadronic decays, the $^3P_0$ and $^3S_1$ models, are currently in use. Attempts to rule out one or the other have been hindered by a poor understanding of final state interactions and by ambiguities in the treatment of relativistic effects. In this article we study meson decays in both models, focussing on certain amplitude ratios for which the relativistic uncertainties largely cancel out (notably the $S/D$ ratios in $b_1\rightarrow\pi\omega$ and $a_1\rightarrow\pi\rho$), and using a Quark Born Formalism to estimate the final state interactions. We find that the $^3P_0$ model is strongly favoured. In addition, we predict a $P/F$ amplitude ratio of $1.6\pm .2$ for the decay $\pi_2\rightarrow\pi\rho$. We also study the parameter-dependence of some individual amplitudes (as opposed to amplitude ratios), in an attempt to identify a ``best'' version of the $^3P_0$ model.Comment: 20 pages, uuencoded postscript file with 7 figures, MIT-CTP-2295; CMU-HEP94-1

WISP genes are members of the connective tissue growth factor family that are up-regulated in Wnt-1-transformed cells and aberrantly expressed in human colon tumors

Wnt family members are critical to many developmental processes, and components of the Wnt signaling pathway have been linked to tumorigenesis in familial and sporadic colon carcinomas. Here we report the identification of two genes, WISP-1 and WISP-2, that are up-regulated in the mouse mammary epithelial cell line C57MG transformed by Wnt-1, but not by Wnt-4. Together with a third related gene, WISP-3, these proteins define a subfamily of the connective tissue growth factor family. Two distinct systems demonstrated WISP induction to be associated with the expression of Wnt-1. These included (i) C57MG cells infected with a Wnt-1 retroviral vector or expressing Wnt-1 under the control of a tetracyline repressible promoter, and (ii) Wnt-1 transgenic mice. The WISP-1 gene was localized to human chromosome 8q24.1-8q24.3. WISP-1 genomic DNA was amplified in colon cancer cell lines and in human colon tumors and its RNA overexpressed (2- to >30-fold) in 84% of the tumors examined compared with patient-matched normal mucosa. WISP-3 mapped to chromosome 6q22-6q23 and also was overexpressed (4- to >40-fold) in 63% of the colon tumors analyzed. In contrast, WISP-2 mapped to human chromosome 20q12-20q13 and its DNA was amplified, but RNA expression was reduced (2- to >30-fold) in 79% of the tumors. These results suggest that the WISP genes may be downstream of Wnt-1 signaling and that aberrant levels of WISP expression in colon cancer may play a role in colon tumorigenesis

Charge Conjugation Invariance of the Vacuum and the Cosmological Constant Problem

We propose a method of field quantization which uses an indefinite metric in a Hilbert space of state vectors. The action for gravity and the standard model includes, as well as the positive energy fermion and boson fields, negative energy fields. The Hamiltonian for the action leads through charge conjugation invariance symmetry of the vacuum to a cancellation of the zero-point vacuum energy and a vanishing cosmological constant in the presence of a gravitational field. To guarantee the stability of the vacuum, we introduce a Dirac sea `hole' theory of quantization for gravity as well as the standard model. The vacuum is defined to be fully occupied by negative energy particles with a hole in the Dirac sea, corresponding to an anti-particle. We postulate that the negative energy bosons in the vacuum satisfy a para-statistics that leads to a para-Pauli exclusion principle for the negative energy bosons in the vacuum, while the positive energy bosons in the Hilbert space obey the usual Bose-Einstein statistics. This assures that the vacuum is stable for both fermions and bosons. Restrictions on the para-operator Hamiltonian density lead to selection rules that prohibit positive energy para-bosons from being observable. The problem of deriving a positive energy spectrum and a consistent unitary field theory from a pseudo-Hermitian Hamiltonian is investigated.Comment: 15 pages, Latex file, no figures. Typos corrected. To be published in Physics Letters

Stimulant Medication and Reading Performance

The study examined the sustained effects of methylphenidate on reading performance in a sample of 42 boys, ages 8 to 11, with attention deficit-hyperactivity disorder (ADHD). Two subgroups were formed based on the presence or absence of co-occurring conduct disorders. Subjects were selected on the basis of their positive response to methylphenidate as determined in a series of original medication trials (Forness, Cantwell, Swanson, Hanna, & Youpa, 1991). For the purpose of this study, subjects were placed on their optimal dose of medication for a 6-week period and then tested on measures of oral reading and reading comprehension equivalent to those used in the original trials, retested after a week without medication (placebo), then tested again the following week after return to medication. Only the subgroup with conduct disorders responded, and this response was limited to reading comprehension improvement in only those subjects who also demonstrated improvement in oral reading on original trials. No response differences were found between subjects with or without learning disabilities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68569/2/10.1177_002221949202500205.pd

Framing immigration and integration: Relationships between press and parliament in the Netherlands

This article examines how the salience and framing of political issues in the press and in parliament influence each other and how this salience and framing is influenced by key events outside the media and parliamentary realms. The case focused on is the debate on immigration and integration in the Netherlands between 1995 and 2004. The empirical analyses are based on a computer-assisted content analysis of both parliamentary documents and newspaper articles. Results show bidirectional causal relationships between media and parliament. In the case of salience only long-term influence relationships are found, while framing influences follow an interesting pattern: an increase in the use of a frame in one arena leads to an increase in the other arena only if this frame has already been used regularly in the latter arena. External events have more considerable and consistent impact on issue salience and framing in both arenas. Copyright © 2007 Sage Publications

Practising social justice: Community organisations, what matters and what counts

This thesis investigates the situated knowing-in-practice of locally-based community organisations, and studies how this practice knowledge is translated and contested in inter-organisational relations in the community services field of practices. Despite participation in government-led consultation processes, community organisations express frustration that the resulting policies and plans inadequately take account of the contributions from their practice knowledge. The funding of locally-based community organisations is gradually diminishing in real terms and in the competitive tendering environment, large nationally-based organisations often attract the new funding sources. The concern of locally-based community organisations is that the apparent lack of understanding of their distinctive practice knowing is threatening their capacity to improve the well-being of local people and their communities. In this study, I work with practitioners, service participants and management committee members to present an account of their knowing-in-practice, its character and conditions of efficacy; and then investigate what happens when this local practice knowledge is translated into results-based accountability (RBA) planning with diverse organisations and institutions. This thesis analyses three points of observation: knowing in a community of practitioners; knowing in a community organisation and knowing in the community services field of practices. In choosing these points of observation, the inquiry explores some of the relations and intra-actions from the single organisation to the institutional at a time when state government bureaucracy has mandated that community organisations implement RBA to articulate outcomes that can be measured by performance indicators. A feminist, performative, relational practice-based approach employs participatory action research to achieve an enabling research experience for the participants. It aims to intervene strategically to enhance recognition of the distinctive contributions of community organisations’ practice knowledge. This thesis reconfigures understandings of the roles, contributions and accountabilities of locally-based community organisations. Observations of situated practices together with the accounts of workers and service participants demonstrate how community organisations facilitate service participants’ struggles over social justice. A new topology for rethinking social justice as processual and practice-based is developed. It demonstrates how these struggles are a dynamic complex of iteratively-enfolded practices of respect and recognition, redistribution and distributive justice, representation and participation, belonging and inclusion. The focus on the practising of social justice in this thesis offers an alternative to the neo-liberal discourse that positions community organisations as sub-contractors accountable to government for delivering measurable outputs, outcomes and efficiencies in specified service provision contracts. The study shows how knowing-in-practice in locally-based community organisations contests the representational conception of knowledge inextricably entangled with accountability and performance measurement apparatus such as RBA. Further, it suggests that practitioner and service participant contributions are marginalised and diminished in RBA through the privileging of knowledge that takes an ‘expert’, quantifiable and calculative form. Thus crucially, harnessing local practice knowing requires re-imagining and enacting knowledge spaces that assemble and take seriously all relevant stakeholder perspectives, diverse knowledges and methods

Visual stress, its treatment with spectral filters, and its relationship to visually induced motion sickness

We review the concept of visual stress and its relation to neurological disease. Visual stress can occur from the observation of images with unnatural spatial structure and an excess of contrast energy at spatial frequencies to which the visual system is generally most sensitive. Visual stress can often be reduced using spectral filters, provided the colour is selected with precision to suit each individual. The use of such filters and their effects on reading speed are reviewed. The filters have been shown to benefit patients with a variety of neurological conditions other than reading difficulty, all associated with an increased risk of seizures. © 2009 Elsevier Ltd

Configuration of anchorage holes affects fixation of the acetabular component in cemented total hip replacement - a finite element study

Our survey of current practice among UK orthopaedic surgeons shows wide variations in fixation techniques. The aim of this study is to investigate the effect of drilling different configurations of anchorage holes in the acetabulum on implant stability. To avoid variables that could incur during in-vitro testing, we used commercially-available COSMOS finite element analysis package to investigate the stress distributions, deformations, and strains on the cement mantle when drilling three large anchorage holes and six smaller ones, with straight and rounded cement pegs. The results, which are in line with our in-vitro studies on simulated reconstructed acetabulae, indicate better stability of the acetabular component when three larger holes than six smaller holes are drilled and when the necks of the anchorage holes are rounded. The longevity of total hip replacements could be improved by drilling three large anchorage holes, rather than many smaller ones, as initially proposed by Charnley

On the Mechanism of Open-Flavor Strong Decays

Open-flavor strong decays are mediated by $q\bar q$ pair production, which is known to occur dominantly with \3p0 quantum numbers. The relation of the phenomenological \3p0 model of these decays to ``microscopic" QCD decay mechanisms has never been clearly established. In this paper we investigate $q\bar q$ meson decay amplitudes assuming pair production from the scalar confining interaction (sKs) and from one gluon exchange (OGE). sKs pair production predicts decay amplitudes of approximately the correct magnitude and D/S amplitude ratios in $b_1\to\omega\pi$ and $a_1\to\rho\pi$ which are close to experiment. The OGE decay amplitude is found to be subdominant in most cases, a notable exception being $^3$P$_0\to{}^1$S$_0+{}^1$S$_0$. The full sKs~+~OGE amplitudes differ significantly from \3p0 model predictions in some channels and can be distinguished experimentally, for example through an accurate comparison of the D/S amplitude ratios in $b_1\to\omega\pi$ and $a_1\to\rho\pi$.Comment: 44 pages, 22 eps figures, RevTex, complete postscript file available at http://csep2.phy.ornl.gov/theory_group/people/barnes/pubs/abs.p