A theory of L1L^1-dissipative solvers for scalar conservation laws with discontinuous flux

We propose a general framework for the study of $L^1$ contractive semigroups of solutions to conservation laws with discontinuous flux. Developing the ideas of a number of preceding works we claim that the whole admissibility issue is reduced to the selection of a family of "elementary solutions", which are certain piecewise constant stationary weak solutions. We refer to such a family as a "germ". It is well known that (CL) admits many different $L^1$ contractive semigroups, some of which reflects different physical applications. We revisit a number of the existing admissibility (or entropy) conditions and identify the germs that underly these conditions. We devote specific attention to the anishing viscosity" germ, which is a way to express the "$\Gamma$-condition" of Diehl. For any given germ, we formulate "germ-based" admissibility conditions in the form of a trace condition on the flux discontinuity line $x=0$ (in the spirit of Vol'pert) and in the form of a family of global entropy inequalities (following Kruzhkov and Carrillo). We characterize those germs that lead to the $L^1$-contraction property for the associated admissible solutions. Our approach offers a streamlined and unifying perspective on many of the known entropy conditions, making it possible to recover earlier uniqueness results under weaker conditions than before, and to provide new results for other less studied problems. Several strategies for proving the existence of admissible solutions are discussed, and existence results are given for fluxes satisfying some additional conditions. These are based on convergence results either for the vanishing viscosity method (with standard viscosity or with specific viscosities "adapted" to the choice of a germ), or for specific germ-adapted finite volume schemes

Towards an asset-based approach to promoting and sustaining well-being for people with aphasia and their families: an international exploratory study

Background: There is growing interest in interventions that promote positive outcomes and well-being for people with aphasia (PWA) and their families, but provision is inconsistent. An asset-based approach, based on the theory of salutogenesis, focuses on what makes you well rather than ill. This approach has been used successfully across a variety of research fields, including health and social care research and practice, and has the potential to provide coherent strategies to support people living successfully with aphasia. Aim: To explore the relevance and potential of an asset-based approach to promoting and sustaining well-being for PWA and their families, across contexts and cultures. Methods & procedures: Exploratory case studies were carried out in the United Kingdom (UK), Norway, Israel, Ireland, and Denmark in a variety of settings. Following an interpretative paradigm, we used qualitative methods including: interviews; appreciative inquiry; group discussions; and participatory action research. 95 PWA and 25 family members were asked to identify assets within themselves and their communities that promote, sustain and maintain well-being, by responding to: “What makes you feel good/well/healthy?” Data were analysed using thematic analysis. Outcomes & results: An asset-based approach proved to be a powerful means for PWA and family members to explore what helps them live well with aphasia. Key themes were identified: (1) personal journey; (2) helping others; (3) connecting to self; (4) connecting to others; (5) recreation; and (6) personal attributes. Self-identification of assets, within the person and their community, and connections to these, helped PWA and their family members to maintain well-being, overcome barriers and regain confidence. Using this approach, focusing on the person’s recognition, activation and mobilisation of assets, could enhance the person’s understanding and restore meaning around the stroke and onset of aphasia. Conclusion: This novel exploratory research demonstrates the relevance and potential across diverse cultural contexts of taking an asset-based approach to promoting and sustaining well-being for PWA and their families. Focusing on maintaining connections to these assets and developing meaning around the event, could prevent some of the negative sequela of stroke. The “patient–professional” relationship must transform into a collaborative partnership, with time and flexibility needed to introduce this approach. Further research should examine how service providers and PWA could develop and operationalise an asset-based approach in clinical and community settings and identify if there is an optimum timing for introducing this approach along the stroke pathway

"Dreaming in colour’: disabled higher education students’ perspectives on improving design practices that would enable them to benefit from their use of technologies"

The focus of this paper is the design of technology products and services for disabled students in higher education. It analyses the perspectives of disabled students studying in the US, the UK, Germany, Israel and Canada, regarding their experiences of using technologies to support their learning. The students shared how the functionality of the technologies supported them to study and enabled them to achieve their academic potential. Despite these positive outcomes, the students also reported difficulties associated with: i) the design of the technologies, ii) a lack of technology know-how and iii) a lack of social capital. When identifying potential solutions to these difficulties the disabled students imagined both preferable and possible futures where faculty, higher education institutions, researchers and technology companies are challenged to push the boundaries of their current design practices

Modelling human choices: MADeM and decision‑making

Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

Dynamic light scattering and

Self-assembling and dynamical properties of deoxyguanosine 5’-monophosphate in isotropic aqueous solutions were studied by 31P NMR spectroscopy and dynamic light scattering (DLS). All solutions had the same c = 4 wt% guanosine concentration, while the added KCl molarity ranged from 0 to 1.5 M. 31P NMR measurements show that potassium ions strongly enhance the stacking process of guanosine tetramers until a saturation is reached at 0.1 M KCl with more than 70% of the molecules aggregated. Polarized light scattering reveals the presence of a fast relaxation mode that arises from the translational dynamics of the self-assembled stacks. The diffusion coefficient of this mode shows a strong dependence on molarity of added salt, which can be described in terms of the coupled mode and counterion condensation theories for polyelectrolyte solutions. Depolarized light scattering reveals the rotational dynamics of the self-assembled stacks which exhibits a pronounced slowing down with increasing the added salt content

Optical second harmonic generation in a ferromagnetic liquid crystal.

A comparative experimental investigation of the dependence of second harmonic generation (SHG) on an applied external voltage between a standard nematic liquid crystalline material and an analogue ferromagnetic nematic liquid crystalline material was performed by using a fundamental optical beam at an 800 nm wavelength. For the ferromagnetic material, the dependence of SHG on an applied magnetic field was also examined. Three different polarization combinations of the fundamental and the second harmonic radiation were analysed. The SHG signal observed in the former material is attributed to a combination of electric field-induced SHG (EFISHG) and flexoelectric deformation-induced SHG, while the SHG signal observed in the latter material is attributed solely to flexoelectric deformation-induced SHG. The obtained dependences of the SHG signal on the associated optical retardation show that, in the most favourable polarization combination, the two contributions generate about the same effective nonlinear optical susceptibility

Dynamic light scattering and 31P NMR study of the self-assembly of deoxyguanosine 5’-monophosphate: the effect of added salt

Self-assembling and dynamical properties of deoxyguanosine 5'-monophosphate in isotropic aqueous solutions were studied by 31P NMR spectroscopy and dynamic light scattering (DLS). All solutions had the same c = 4 wt% guanosine concentration, while the added KCl molarity ranged from 0 to 1.5 M. 31P NMR measurements show that potassium ions strongly enhance the stacking process of guanosine tetramers until a saturation is reached at 0.1 M KCl with more than 70% of the molecules aggregated. Polarized light scattering reveals the presence of a fast relaxation mode that arises from the translational dynamics of the self-assembled stacks. The diffusion coefficient of this mode shows a strong dependence on molarity of added salt, which can be described in terms of the coupled mode and counterion condensation theories for polyelectrolyte solutions. Depolarized light scattering reveals the rotational dynamics of the self-assembled stacks which exhibits a pronounced slowing down with increasing the added salt conten

Dynamic light scattering and \chem{^{31}P} NMR spectroscopy study of the self-assembly of deoxyguanosine \mth{5'}-monophosphate

Self-assembling properties of deoxyguanosine $5'$-monophosphate in isotropic solutions of concentrations from 0.5 wt% to 15 wt% were investigated by dynamic light scattering (DLS) and \chem{^{31}P} NMR spectroscopy. A slow diffusive mode with a diffusion coefficient $D_{\rm slow} \sim 10^{-12}$ m$^{2}$/s was detected by DLS for the whole concentration range. This mode is assigned to the translational motion of large globular aggregates, similar to those observed in DNA and other polyelectrolyte solutions. The existence of such aggregates was confirmed by freeze fracture electron microscopy. Close to the isotropic-cholesteric phase transition, at 4 wt% $\leqslant c \leqslant 10$ wt%, also a faster diffusive mode is observed in the polarized DLS response and a very fast mode is detected by depolarized DLS. These modes are related to translational and rotational diffusion of the columnar stacks of guanosine molecules, which are favorably formed in the relatively narrow pretransitional region. The stacking was also revealed from the appearance of a secondary resonance line in the \chem{^{31}P} NMR spectra. Using the hydrodynamic theory of Tirado and Garcia de la Torre, the length of the cylindrical stacks was found to be $L = 364 \pm 78$ Å, which is significantly larger than the values reported for other guanosine derivatives