New measurements of Cabibbo-suppressed decays of mesons with the CLEO-c detector

Using of data collected with the CLEO-c detector, we report on first observations and measurements of Cabibbo-suppressed decays of D mesons in the following six decay modes: pi+ pi- pi0 pi0, pi+ pi+ pi- pi- pi0, pi+ pi0 pi0, pi+ pi+ pi- pi0, eta pi0, and omega pi+ pi-. Improved branching fraction measurements in eight other multipion decay modes are also presented. The measured D --> pi pi rates allow us to extract the ratio of isospin amplitudes A(DeltaI = (3/2) / A(DeltaI = (1/2)) = 0.420 +/- 0.014(stat) +/- 0.016(syst) and the strong phase shift of delta1 = (86.4 +/- 2.8 +/- 3.3) degrees, which is quite large and now more precisely determined.     

Search for exclusive multibody non- decays at the resonance

Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e+e- storage ring, we present searches for 25 charmless decay modes of the psi(3770), mostly multibody final states. No evidence for charmless decays is found.     

A forest building process on simple graphs

Consider the following process on a simple graph without isolated vertices: order the edges randomly and keep an edge if and only if it contains a vertex which is not contained in some preceding edge. The resulting set of edges forms a spanning forest of the graph.The probability of obtaining $k$ components in this process for complete bipartite graphs is determined as well as a formula for the expected number of components in any graph. A generic recurrence and some additional basic properties are discussed.     

Aronszajn and Kurepa trees

Monroe Eskew (Tree properties on \(\omega _1\) and \(\omega _2\), 2016. https://mathoverflow.net/questions/217951/tree-properties-on-omega-1-and-omega-2) asked whether the tree property at \(\omega _2\) implies there is no Kurepa tree (as is the case in the Mitchell model, or under PFA). We prove that the tree property at \(\omega _2\) is consistent with the existence of \(\omega _1\)-trees with as many branches as desired.     

Strategies for mitigating an influenza pandemic

Development of strategies for mitigating the severity of a new influenza pandemic is now a top global public health priority. Influenza prevention and containment strategies can be considered under the broad categories of antiviral, vaccine and non-pharmaceutical (case isolation, household quarantine, school or workplace closure, restrictions on travel) measures. Mathematical models are powerful tools for exploring this complex landscape of intervention strategies and quantifying the potential costs and benefits of different options. Here we use a large-scale epidemic simulation to examine intervention options should initial containment of a novel influenza outbreak fail, using Great Britain and the United States as examples. We find that border restrictions and/or internal travel restrictions are unlikely to delay spread by more than 2-3 weeks unless more than 99% effective. School closure during the peak of a pandemic can reduce peak attack rates by up to 40%, but has little impact on overall attack rates, whereas case isolation or household quarantine could have a significant impact, if feasible. Treatment of clinical cases can reduce transmission, but only if antivirals are given within a day of symptoms starting. Given enough drugs for 50% of the population, household-based prophylaxis coupled with reactive school closure could reduce clinical attack rates by 40-50%. More widespread prophylaxis would be even more logistically challenging but might reduce attack rates by over 75%. Vaccine stockpiled in advance of a pandemic could significantly reduce attack rates even if of low efficacy. Estimates of policy effectiveness will change if the characteristics of a future pandemic strain differ substantially from those seen in past pandemics.     

Central nervous system control of food intake and body weight

The capacity to adjust food intake in response to changing energy requirements is essential for survival. Recent progress has provided an insight into the molecular, cellular and behavioural mechanisms that link changes of body fat stores to adaptive adjustments of feeding behaviour. The physiological importance of this homeostatic control system is highlighted by the severe obesity that results from dysfunction of any of several of its key components. This new information provides a biological context within which to consider the global obesity epidemic and identifies numerous potential avenues for therapeutic intervention and future research.     

Hydrogen-bonded LC nanocomposites: characterisation of nanoparticle-LC interactions by solid-state NMR and FTIR spectroscopies

Although the molecular-level nanoparticle-liquid crystal (NP-LC) interactions are key for forming stable NP dispersions in LC, characterisation of these interactions is scarce in the literature. Recently, we have developed hydrogen-bonded LC nanocomposites based on mesogenic carboxylic acids and NPs functionalised with hydrogen-bond acceptor/donor groups. Here, we apply solid-state ¹H and ¹³C NMR and Fourier transform infrared spectroscopies to model systems consisting of mixtures of trans-4-n-butylcyclohexanecarboxylic acid (4-BCHA), 4-hexylbenzoic acid (6BA) and 4,4?-bipyridine. The binary mixture, 4-BCHA:6BA, was also studied. The results were compared to monolayer quantities of 6BA and 4-BCHA adsorbed on pyridine functionalised zirconia NPs (ZrO₂-n₃-pyridine) to understand the different effects of the functionalised NPs on the LC properties.     

Filtration with Multiple Species of Particles

Transport in Porous Media - Membrane filtration of feed containing multiple species of particles is a common process in the industrial setting. In this work, we propose a model for filtration of a...     

Chemoselectivity in the Kosugi-Migita-Stille coupling of bromophenyl triflates and bromo-nitrophenyl triflates with (ethenyl)tributyltin

Kosugi-Migita-Stille cross coupling reactions of (ethenyl)tributyltin with all isomeric permutations of bromophenyl triflate and bromo-nitrophenyl triflate were examined in order to determine the chemoselectivity of carbon-bromine versus carbon-triflate bond coupling under different reaction conditions. In general, highly selective carbon-bromine bond cross couplings were observed using for example bis(triphenylphosphine)palladium dichloride (2?mol-%) in 1,4-dioxane at reflux. In contrast, reactions using the same pre-catalyst but in the presence of a three-fold excess of lithium chloride in N,N-dimethylformamide at ambient temperature were in most cases selective for coupling at the carbon-triflate bond. Overall, isolated yields and the selectivity for carbon-bromine bond coupling were significantly higher compared to carbon-triflate bond coupling.