Dynamics of Conformal Maps for a Class of Non-Laplacian Growth Phenomena

Time-dependent conformal maps are used to model a class of growth phenomena limited by coupled non-Laplacian transport processes, such as nonlinear diffusion, advection, and electro-migration. Both continuous and stochastic dynamics are described by generalizing conformal-mapping techniques for viscous fingering and diffusion-limited aggregation, respectively. A general notion of time in stochastic growth is also introduced. The theory is applied to simulations of advection-diffusion-limited aggregation in a background potential flow. A universal crossover in morphology is observed from diffusion-limited to advection-limited fractal patterns with an associated crossover in the growth rate, controlled by a time-dependent effective Peclet number. Remarkably, the fractal dimension is not affected by advection, in spite of dramatic increases in anisotropy and growth rate, due to the persistence of diffusion limitation at small scales.Comment: 4 pages, 2 figures (six color plates

The physical and mental health of acute psychiatric ward staff, and its relationship to experience of physical violence

To evaluate and describe the physical and mental health of staff on acute psychiatric wards and examine whether violence exposure is linked with health status. We undertook a cross-sectional survey with 564 nursing staff and healthcare assistants from 31 psychiatric wards in nine NHS Trusts using the SF-36, a reliable and valid measure of health status and compared summary scores with national normative data. Additional violence exposure data were collated simultaneously and also compared with health status. The physical health of staff was worse, and their mental health was better than the general population. Physical health data were skewed and showed a small number of staff in relatively poor health while the majority were above average. Better physical health was associated with less time in the current post, a higher pay grade, and less exposure to mild physical violence in the past year. Better mental health was associated with being older and from an ethnic minority background. Violence exposure influenced physical health but not mental health when possible confounders were considered. Mental health was strongly influenced by ethnicity, and further research might highlight the impact on own-group ethnic density on the quality of care. The impact of staff whom are physically unwell or impaired in the workplace needs to be considered as the quality of care may be compromised despite this being an example of inclusiveness, equal opportunities employment, and positive staff motivation

A phenomenological approach to the simulation of metabolism and proliferation dynamics of large tumour cell populations

A major goal of modern computational biology is to simulate the collective behaviour of large cell populations starting from the intricate web of molecular interactions occurring at the microscopic level. In this paper we describe a simplified model of cell metabolism, growth and proliferation, suitable for inclusion in a multicell simulator, now under development (Chignola R and Milotti E 2004 Physica A 338 261-6). Nutrients regulate the proliferation dynamics of tumor cells which adapt their behaviour to respond to changes in the biochemical composition of the environment. This modeling of nutrient metabolism and cell cycle at a mesoscopic scale level leads to a continuous flow of information between the two disparate spatiotemporal scales of molecular and cellular dynamics that can be simulated with modern computers and tested experimentally.Comment: 58 pages, 7 figures, 3 tables, pdf onl

Circulating Prostate-Specific Antigen and Telomere Length in a Nationally Representative Sample of Men Without History of Prostate Cancer

BACKGROUND: We investigated the association of prostate-specific antigen (PSA) with leukocyte telomere length, which may be altered in preclinical prostate malignancies. METHODS: This study was based on the 2001-2002 U.S. National Health and Nutrition Examination Survey (NHANES). A subsample of 1,127 men aged 40-85 years without prior history of prostate cancer who provided informed consent and blood samples were selected. Leukocyte telomere length (LTL) relative to standard DNA reference (T/S ratio) was quantified by polymerase chain reaction (PCR). Survey-weighted multivariable linear regression was performed to examine T/S ratio across quintiles of total and free PSA and free-to-total PSA ratio (%fPSA). A sensitivity analysis was performed by excluding men dying from prostate cancer during follow-up through to December 31, 2006. Stratification analyses were carried out to assess any effect modification by age group, race, body mass index (BMI), and levels of C-reactive protein (CRP), a marker of inflammation. RESULTS: Higher total PSA levels were associated to longer LTL, with approximately 8% increase in log-transformed T/S ratio (95% confidence interval [CI]: 2-13%) among men in the highest quintile of total PSA compared to the lowest in the fully adjusted model (Ptrend  = 0.01). No significant association was found for free PSA or %fPSA, although nonlinearity between all PSA measures and T/S ratio was indicated. Similar results were found after excluding men who died from prostate cancer during follow-up. We also found the associations between total PSA and T/S ratio to be strongest among non-Hispanic blacks, non-obese men (BMI <30 kg/m(2) ), and those with low CRP. However, a significant interaction was only found between total PSA and race/ethnicity (Pinteraction  = 0.01). CONCLUSION: Total PSA levels were strongly associated to LTL, particularly among non-Hispanic blacks. Our findings support a potential link between PSA and specific mechanisms contributing to prostate cancer development. Prostate 77:22-32, 2017. © 2016 Wiley Periodicals, Inc

Learning to learn in supported parent and toddler groups : a sociocultural investigation

Over the last 50 years research has consistently suggested that some types of adult\ud guidance can improve upon 'pure discovery learning' (Mayer, 2004). In the preschool\ud age group studies have suggested that pedagogical strategies identified with\ud Scaffolding, Sustained Shared Thinking, and Co-construction can be advantageous to\ud children's later educational success (Siraj-Blatchford & Sylva, 2004). This thesis\ud examines the cultural practices of adults supporting children's learning in 'free play'\ud during practitioner facilitated 'Parent and Toddler Group' sessions to consider the\ud extent to which these children are being guided towards participating in collaborative\ud learning interactions (Rogoff 1998) by both practitioners and parents.\ud The investigative approach adopted is informed by Socio-cultural theory (Hedegaard\ud & Fleer, 2008, Rogoff, 1998) and develops the complementary use of affordance\ud theory (Gibson, 1979) to investigate the learner as part of a system of mutually\ud effective elements. The thesis draws on observations of 12 children's interactions in\ud two ethnographic case studies set in context by interview and survey data. The thesis\ud identifies and describes a range of modes of interaction employed in the case study\ud parent and toddler groups. The thesis shows how children's experiences vary as a\ud result of the balance of modes that they experience. It suggests strategies to broaden\ud parents' and practitioners' awareness of promoting children's learning through a\ud range of modes of interaction.\ud The study findings echo those of international studies suggesting that early education\ud contexts may encourage individual and peer-learning much more frequently than\ud collaborative learning with adults (Pramling-Samuelsson & Fleer, 2009, Rogoff,\ud 1998)

Measurements of the branching fractions of B+→ppK+ decays

The branching fractions of the decay B+ → pp̄K+ for different intermediate states are measured using data, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment. The total branching fraction, its charmless component Mpp̄ < 2.85 GeV/c2 and the branching fractions via the resonant cc̄ states η c(1S) and ψ(2S) relative to the decay via a J/ψ intermediate state are [Equation not available: see fulltext.] Upper limits on the B + branching fractions into the η c(2S) meson and into the charmonium-like states X(3872) and X(3915) are also obtained

Measurement of the mass and lifetime of the Ωb−\Omega_b^- baryon

A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb$^{-1}$ collected by LHCb at $\sqrt{s}=7$ and 8 TeV, is used to reconstruct $63\pm9$ $\Omega_b^-\to\Omega_c^0\pi^-$, $\Omega_c^0\to pK^-K^-\pi^+$ decays. Using the $\Xi_b^-\to\Xi_c^0\pi^-$, $\Xi_c^0\to pK^-K^-\pi^+$ decay mode for calibration, the lifetime ratio and absolute lifetime of the $\Omega_b^-$ baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for $\tau_{\Omega_b^-}$ only). A measurement is also made of the mass difference, $m_{\Omega_b^-}-m_{\Xi_b^-}$, and the corresponding $\Omega_b^-$ mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm

Model-independent evidence for J/ψpJ/\psi p contributions to Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays

The data sample of $\Lambda_b^0\to J/\psi p K^-$ decays acquired with the LHCb detector from 7 and 8~TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$, is inspected for the presence of $J/\psi p$ or $J/\psi K^-$ contributions with minimal assumptions about $K^- p$ contributions. It is demonstrated at more than 9 standard deviations that $\Lambda_b^0\to J/\psi p K^-$ decays cannot be described with $K^- p$ contributions alone, and that $J/\psi p$ contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for $P_c^+\to J/\psi p$ charmonium-pentaquark states in the same data sample.Comment: 21 pages, 12 figures (including the supplemental section added at the end

Energy loss in systems of stacked rocking bodies

Free-standing bodies, which rock in response to dynamic base excitations, can be found in a wide range of applications. There are many instances, for example a museum artifact seated on a support pedestal, where both the object and its support are free-standing, resulting in a dynamic system where both bodies can rock with respect to their contact interfaces. This paper analyzes the rich dynamics of systems of two stacked rocking bodies. It focuses on the location of the resultant impulses between bodies during impact, considering their effect on the overall stability of the system. The widely-used assumption that the impulses occur at the future rocking corners is shown to be the least conservative scenario and often leads to underestimating the likelihood of failure. The optimum configuration of two stacked blocks is found to be highly sensitive to the characteristics of the input motion and to the location of the impulses