Variational two-particle density matrix calculation for the Hubbard model below half filling using spin-adapted lifting conditions

The variational determination of the two-particle density matrix is an interesting, but not yet fully explored technique that allows to obtain ground-state properties of a quantum many-body system without reference to an $N$-particle wave function. The one-dimensional fermionic Hubbard model has been studied before with this method, using standard two- and three-index conditions on the density matrix [J. R. Hammond {\it et al.}, Phys. Rev. A 73, 062505 (2006)], while a more recent study explored so-called subsystem constraints [N. Shenvi {\it et al.}, Phys. Rev. Lett. 105, 213003 (2010)]. These studies reported good results even with only standard two-index conditions, but have always been limited to the half-filled lattice. In this Letter we establish the fact that the two-index approach fails for other fillings. In this case, a subset of three-index conditions is absolutely needed to describe the correct physics in the strong-repulsion limit. We show that applying lifting conditions [J.R. Hammond {\it et al.}, Phys. Rev. A 71, 062503 (2005)] is the most economical way to achieve this, while still avoiding the computationally much heavier three-index conditions. A further extension to spin-adapted lifting conditions leads to increased accuracy in the intermediate repulsion regime. At the same time we establish the feasibility of such studies to the more complicated phase diagram in two-dimensional Hubbard models.Comment: 10 pages, 2 figure

Subject preferences of fifth-grade children.

Thesis (Ed.M.)--Boston University N.B.:Pages 155 and 309 are missing from original thesis

An evaluation of collaborative research partnerships in occupational therapy education

A lack of skills and confidence in carrying out research has been identified amongst occupational therapists (Pighills et al, 2013). The consequent predominance of university-led research threatens to exacerbate the practice-research gap (Kielhofner, 2005). This poster describes the benefits and challenges of collaborative research partnerships (Crist, 2010) for occupational therapy students, practice partners and academic supervisors. The aim of the project was to explore the benefits and challenges of the research partnerships from the perspectives of key stakeholders. Action research methodology was used. Five BSc, two MSc (pre-registration) students, six practice partners and four academic supervisors were recruited. Data was collected using questionnaire surveys and semi-structured interviews. All data were analysed thematically. Ethical and research governance approvals were gained from University of Cumbria and relevant NHS trusts respectively. The study was funded by the Higher Education Academy and the University of Cumbria. Findings identified benefits for each stakeholder group. Students emphasised increased confidence and a sense of value and purpose in contributing to future service improvements. Practice partners valued the research findings to aid reflection on working practices and potential service development. Academic supervisors described satisfaction in building enhanced research capacity through practice-based projects. Communication challenges and increased stress and workload were reported; however, these did not outweigh the benefits. Importantly, the research collaborations were perceived to contribute to service enhancements and therefore yield benefits for service-users. These findings illustrate the potential of collaborative research partnerships to build confidence and research capacity in future occupational therapists and thereby assist in reduction of the practice-research divide and support service development. Crist, P.A. (2010) Adapting Research Instruction to Support the Scholarship of Practice: Practice-Scholar Partnerships. Occupational Therapy in Health Care, 24(1), 39–55. Kielhofner, G. (2005) A scholarship of practice: Creating discourse between theory, research and practice. Occupational Therapy in Health Care, 19(1/2), 7–16. Pighills, A. C., Plummer, D., Harvey, D., Pain, T. (2013) Positioning occupational therapy as a discipline on the research continuum: Results of a cross-sectional survey of research experience. Australian Occupational Therapy Journal, 60(4), 241–251

An Unbiased Survey of 500 Nearby Stars for Debris Disks: A JCMT Legacy Program

We present the scientific motivation and observing plan for an upcoming detection survey for debris disks using the James Clerk Maxwell Telescope. The SCUBA-2 Unbiased Nearby Stars (SUNS) Survey will observe 500 nearby main sequence and sub-giant stars (100 of each of the A, F, G, K and M spectral classes) to the 850 micron extragalactic confusion limit to search for evidence of submillimeter excess, an indication of circumstellar material. The survey distance boundaries are 8.6, 16.5, 22, 25 and 45 pc for M, K, G, F and A stars, respectively, and all targets lie between the declinations of -40 deg to 80 deg. In this survey, no star will be rejected based on its inherent properties: binarity, presence of planetary companions, spectral type or age. This will be the first unbiased survey for debris disks since IRAS. We expect to detect ~125 debris disks, including ~50 cold disks not detectable in current shorter wavelength surveys. A substantial amount of complementary data will be required to constrain the temperatures and masses of discovered disks. High resolution studies will likely be required to resolve many of the disks. Therefore, these systems will be the focus of future observational studies using a variety of observatories to characterize their physical properties. For non-detected systems, this survey will set constraints (upper limits) on the amount of circumstellar dust, of typically 200 times the Kuiper Belt mass, but as low as 10 times the Kuiper Belt mass for the nearest stars in the sample (approximately 2 pc).Comment: 11 pages, 7 figures (3 color), accepted by the Publications of the Astronomical Society of the Pacifi

Effectiveness and cost-effectiveness of traditional and new partner notification technologies for curable sexually transmitted infections: observational study, systematic reviews and mathematical modelling.

BACKGROUND: Partner notification is essential to the comprehensive case management of sexually transmitted infections. Systematic reviews and mathematical modelling can be used to synthesise information about the effects of new interventions to enhance the outcomes of partner notification. OBJECTIVE: To study the effectiveness and cost-effectiveness of traditional and new partner notification technologies for curable sexually transmitted infections (STIs). DESIGN: Secondary data analysis of clinical audit data; systematic reviews of randomised controlled trials (MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials) published from 1 January 1966 to 31 August 2012 and of studies of health-related quality of life (HRQL) [MEDLINE, EMBASE, ISI Web of Knowledge, NHS Economic Evaluation Database (NHS EED), Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA)] published from 1 January 1980 to 31 December 2011; static models of clinical effectiveness and cost-effectiveness; and dynamic modelling studies to improve parameter estimation and examine effectiveness. SETTING: General population and genitourinary medicine clinic attenders. PARTICIPANTS: Heterosexual women and men. INTERVENTIONS: Traditional partner notification by patient or provider referral, and new partner notification by expedited partner therapy (EPT) or its UK equivalent, accelerated partner therapy (APT). MAIN OUTCOME MEASURES: Population prevalence; index case reinfection; and partners treated per index case. RESULTS: Enhanced partner therapy reduced reinfection in index cases with curable STIs more than simple patient referral [risk ratio (RR) 0.71; 95% confidence interval (CI) 0.56 to 0.89]. There are no randomised trials of APT. The median number of partners treated for chlamydia per index case in UK clinics was 0.60. The number of partners needed to treat to interrupt transmission of chlamydia was lower for casual than for regular partners. In dynamic model simulations, >10% of partners are chlamydia positive with look-back periods of up to 18 months. In the presence of a chlamydia screening programme that reduces population prevalence, treatment of current partners achieves most of the additional reduction in prevalence attributable to partner notification. Dynamic model simulations show that cotesting and treatment for chlamydia and gonorrhoea reduce the prevalence of both STIs. APT has a limited additional effect on prevalence but reduces the rate of index case reinfection. Published quality-adjusted life-year (QALY) weights were of insufficient quality to be used in a cost-effectiveness study of partner notification in this project. Using an intermediate outcome of cost per infection diagnosed, doubling the efficacy of partner notification from 0.4 to 0.8 partners treated per index case was more cost-effective than increasing chlamydia screening coverage. CONCLUSIONS: There is evidence to support the improved clinical effectiveness of EPT in reducing index case reinfection. In a general heterosexual population, partner notification identifies new infected cases but the impact on chlamydia prevalence is limited. Partner notification to notify casual partners might have a greater impact than for regular partners in genitourinary clinic populations. Recommendations for future research are (1) to conduct randomised controlled trials using biological outcomes of the effectiveness of APT and of methods to increase testing for human immunodeficiency virus (HIV) and STIs after APT; (2) collection of HRQL data should be a priority to determine QALYs associated with the sequelae of curable STIs; and (3) standardised parameter sets for curable STIs should be developed for mathematical models of STI transmission that are used for policy-making. FUNDING: The National Institute for Health Research Health Technology Assessment programme

Tyrosine Phosphorylation of Tau by the Src Family Kinases Lck and Fyn

<p>Abstract</p> <p>Background</p> <p>Tau protein is the principal component of the neurofibrillary tangles found in Alzheimer's disease, where it is hyperphosphorylated on serine and threonine residues, and recently phosphotyrosine has been demonstrated. The Src-family kinase Fyn has been linked circumstantially to the pathology of Alzheimer's disease, and shown to phosphorylate Tyr18. Recently another Src-family kinase, Lck, has been identified as a genetic risk factor for this disease.</p> <p>Results</p> <p>In this study we show that Lck is a tau kinase. <it>In vitro</it>, comparison of Lck and Fyn showed that while both kinases phosphorylated Tyr18 preferentially, Lck phosphorylated other tyrosines somewhat better than Fyn. In co-transfected COS-7 cells, mutating any one of the five tyrosines in tau to phenylalanine reduced the apparent level of tau tyrosine phosphorylation to 25-40% of that given by wild-type tau. Consistent with this, tau mutants with only one remaining tyrosine gave poor phosphorylation; however, Tyr18 was phosphorylated better than the others.</p> <p>Conclusions</p> <p>Fyn and Lck have subtle differences in their properties as tau kinases, and the phosphorylation of tau is one mechanism by which the genetic risk associated with Lck might be expressed pathogenically.</p

Kindlin-1 promotes pulmonary breast cancer metastasis

Abstract In breast cancer, increased expression of the cytoskeletal adaptor protein Kindlin-1 has been linked to increased risks of lung metastasis, but the functional basis is unknown. Here, we show that in a mouse model of polyomavirus middle T antigen–induced mammary tumorigenesis, loss of Kindlin-1 reduced early pulmonary arrest and later development of lung metastasis. This phenotype relied on the ability of Kindlin-1 to bind and activate β integrin heterodimers. Kindlin-1 loss reduced α4 integrin–mediated adhesion of mammary tumor cells to the adhesion molecule VCAM-1 on endothelial cells. Treating mice with an anti–VCAM-1 blocking antibody prevented early pulmonary arrest. Kindlin-1 loss also resulted in reduced secretion of several factors linked to metastatic spread, including the lung metastasis regulator tenascin-C, showing that Kindlin-1 regulated metastatic dissemination by an additional mechanism in the tumor microenvironment. Overall, our results show that Kindlin-1 contributes functionally to early pulmonary metastasis of breast cancer. Significance: These findings provide a mechanistic proof in mice that Kindin-1, an integrin-binding adaptor protein, is a critical mediator of early lung metastasis of breast cancer. Cancer Res; 78(6); 1484–96. ©2018 AACR.</jats:p

Management of Fracture Risk in Patients with Chronic Obstructive Pulmonary Disease (COPD): Building a UK Consensus Through Healthcare Professional and Patient Engagement

Introduction: Osteoporosis and bone fractures are common in chronic obstructive pulmonary disease (COPD) and contribute significantly to morbidity and mortality. Current national guidance on COPD management recommends addressing bone health in patients, however, does not detail how. This consensus outlines key elements of a structured approach to managing bone health and fracture risk in patients with COPD.Methods: A systematic approach incorporating multifaceted methodologies included detailed patient and healthcare professional (HCP) surveys followed by a roundtable meeting to reach a consensus on what a pathway would look like.Results: The surveys revealed that fracture risk was not always assessed despite being recognised as an important aspect of COPD management by HCPs. The majority of the patients also stated they would be receptive to discussing treatment options if found to be at risk of osteoporotic fractures. Limited time and resource allocation were identified as barriers to addressing bone health during consultations. The consensus from the roundtable meeting was that a proactive systematic approach to assessing bone health should be adopted. This should involve using fracture risk assessment tools to identify individuals at risk, investigating secondary causes of osteoporosis if a diagnosis is made and reinforcing non-pharmacological and preventative measures such as smoking cessation, keeping active and pharmacological management of osteoporosis and medicines management of corticosteroid use. Practically, prioritising patients with important additional risk factors, such as previous fragility fractures, older age and long-term oral corticosteroid use for an assessment, was felt required.Conclusion: There is a need for integrating fracture risk assessment into the COPD pathway. Developing a systematic and holistic approach to addressing bone health is key to achieving this. In tandem, opportunities to disseminate the information and educational resources are also required