Fabrication of free-standing ordered fluorescent polymer nanofibres by electrospinning

The authors are grateful to the Engineering and Physical Sciences Research Council for financial support.We demonstrate a static fabrication approach to make free-standing ordered arrays of fluorescent nanofibres through control of the transverse electrospinning field. The alignment and the density of the nanofibre arrays are optimised by careful design of both the source and collector electrode geometries which can control the transverse electric field over the full path of the jet. In doing so, we fabricate suspended fluorescent nanofibres with an aspect ratio of 10(4), and with a substantially increased density and order parameter (by a factor of similar to 10 compared to random deposition). Electrostatic modelling suggests that the field distribution of the component is the main contribution to the ordering between the plates. This method offers increased efficiency for the creation of ordered fibres collected over a small area and the characterisation of their photoluminescent properties.Publisher PDFPeer reviewe

Dynamics of the two-dimensional S=1/2 dimer system (C5H6N2F)2CuCl4

Inelastic neutron scattering was used to study a quantum S=1/2 antiferromagnetic Heisenberg system-Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II). The magnetic excitation spectrum was shown to be dominated by long-lived excitations with an energy gap as 1.07(3) meV. The measured dispersion relation is consistent with a simple two-dimensional square lattice of weakly-coupled spin dimers. Comparing the data to a random phase approximation treatment of this model gives the intra-dimer and inter-dimer exchange constants J=1.45(2) meV and J'=0.31(3) meV, respectively.Comment: 4 pages, 4 figure

ESR modes in a Strong-Leg Ladder in the Tomonaga-Luttinger Liquid Phase

Magnetic excitations in the strong-leg quantum spin ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_4$ (known as DIMPY) in the field-induced Tomonaga-Luttinger spin liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual non-linear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe its ESR observability to the uniform Dzyaloshinskii-Moriya interaction

Emergency and on-demand health care: modelling a large complex system

This paper describes how system dynamics was used as a central part of a whole-system review of emergency and on-demand health care in Nottingham, England. Based on interviews with 30 key individuals across health and social care, a 'conceptual map' of the system was developed, showing potential patient pathways through the system. This was used to construct a stock-flow model, populated with current activity data, in order to simulate patient flows and to identify system bottle-necks. Without intervention, assuming current trends continue, Nottingham hospitals are unlikely to reach elective admission targets or achieve the government target of 82% bed occupancy. Admissions from general practice had the greatest influence on occupancy rates. Preventing a small number of emergency admissions in elderly patients showed a substantial effect, reducing bed occupancy by 1% per annum over 5 years. Modelling indicated a range of undesirable outcomes associated with continued growth in demand for emergency care, but also considerable potential to intervene to alleviate these problems, in particular by increasing the care options available in the community

Effect of organic, low-input and conventional production systems on yield and diseases in winter barley

The effect of organic, low-input and conventional management practices on barley yield and disease incidence was assessed in field trials over two years. Conventional fertility management (based on mineral fertiliser applications) and conventional crop protection (based on chemosynthetic pesticides) significantly increased the yield of winter barley as compared to organic fertility and crop protection regimes. Severity of leaf blotch (Rhynchosporium secalis) was highest under organic fertility and crop protection management and was correlated inversely with yield. For mildew (Erysiphe graminis), an interaction between fertility management and crop protection was detected. Conventional crop protection reduced severity of the disease, only under conventional fertility management. Under organic fertility management, incidence of mildew was low and application of synthetic pesticides in “low input” production systems had no significant effect on disease severity

The Family Employment Awareness Training (FEAT): A Mixed-method Follow-up

This is the author's accepted manuscript. The original publication is available at http://dx.doi.org/10.3233/JVR-130652.BACKGROUND: Although competitive employment (i.e., employment in community settings among peers without disabilities for minimum wage or higher) is associated with numerous benefits for individuals with disabilities (Johannesen, McGrew, Griss, & Born, 2007), people with disabilities are underrepresented in the competitive workforce (National Disability Rights Network, 2011). OBJECTIVES: This study sought to determine the longer-term effectiveness of the Family Employment Awareness Training (FEAT) on the expectations and knowledge of participants who attended the program in 2010-2011. The study also sought to explore the perceptions of families who attended the program. METHODS: We distributed a FEAT Follow-up Survey to 220 participants to evaluate the program’s longer-term influence on participants’ expectations and knowledge and conducted 13 semi-structured interviews using a FEAT Interview Protocol to explore families’ perceptions. RESULTS: Study findings indicated that participants who attended FEAT rated their expectations as average and rated their knowledge above average one to two years after attending FEAT. An analysis of interview data indicated that families described several aspects of FEAT they liked, aspects they disliked, and suggested improvements for the program. CONCLUSIONS: Results from this study indicate that FEAT is a promising approach to improving competitive employment outcomes for individuals with disabilities

Magnetothermal transport in the spin-1/2 chains of copper pyrazine dinitrate

We present experiments on the thermal transport in the spin-1/2 chain compound copper pyrazine dinitrate Cu(C_4 H_4 N_2)(NO_3)_2. The heat conductivity shows a surprisingly strong dependence on the applied magnetic field B, characterized at low temperatures by two main features. The first one appearing at low B is a characteristic dip located at mu_B B ~ k_B T, that may arise from Umklapp scattering. The second one is a plateau-like feature in the quantum critical regime, mu_B |B-B_c| < k_B T, where B_c is the saturation field at T=0. The latter feature clearly points towards a momentum and field independent mean free path of the spin excitations, contrary to theoretical expectations.Comment: 4 pages, 4 figure