High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis

We present a generic approach for treating the effect of nuclear motion in the high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH$_4$ and CD$_4$ and thereby provide direct theoretical support for a recent experiment [Baker {\it et al.}, Science {\bf 312}, 424 (2006)] that uses high-order harmonic generation to probe the ultra-fast structural nuclear rearrangement of ionized methane.Comment: 6 pages, 6 figure

The cytoplasm of living cells: A functional mixture of thousands of components

Inside every living cell is the cytoplasm: a fluid mixture of thousands of different macromolecules, predominantly proteins. This mixture is where most of the biochemistry occurs that enables living cells to function, and it is perhaps the most complex liquid on earth. Here we take an inventory of what is actually in this mixture. Recent genome-sequencing work has given us for the first time at least some information on all of these thousands of components. Having done so we consider two physical phenomena in the cytoplasm: diffusion and possible phase separation. Diffusion is slower in the highly crowded cytoplasm than in dilute solution. Reasonable estimates of this slowdown can be obtained and their consequences explored, for example, monomer-dimer equilibria are established approximately twenty times slower than in a dilute solution. Phase separation in all except exceptional cells appears not to be a problem, despite the high density and so strong protein-protein interactions present. We suggest that this may be partially a byproduct of the evolution of other properties, and partially a result of the huge number of components present.Comment: 11 pages, 1 figure, 1 tabl

Bosonic Reduction of Susy Generalized Harry Dym Equation

In this paper we construct the two component supersymmetric generalized Harry Dym equation which is integrable and study various properties of this model in the bosonic limit. In particular, in the bosonic limit we obtain a new integrable system which, under a hodograph transformation, reduces to a coupled three component system. We show how the Hamiltonian structure transforms under a hodograph transformation and study the properties of the model under a further reduction to a two component system. We find a third Hamiltonian structure for this system (which has been shown earlier to be a bi-Hamiltonian system) making this a genuinely tri-Hamiltonian system. The connection of this system to the modified dispersive water wave equation is clarified. We also study various properties in the dispersionless limit of our model.Comment: 21 page

Could humans recognize odor by phonon assisted tunneling?

Our sense of smell relies on sensitive, selective atomic-scale processes that are initiated when a scent molecule meets specific receptors in the nose. However, the physical mechanisms of detection are not clear. While odorant shape and size are important, experiment indicates these are insufficient. One novel proposal suggests inelastic electron tunneling from a donor to an acceptor mediated by the odorant actuates a receptor, and provides critical discrimination. We test the physical viability of this mechanism using a simple but general model. Using values of key parameters in line with those for other biomolecular systems, we find the proposed mechanism is consistent both with the underlying physics and with observed features of smell, provided the receptor has certain general properties. This mechanism suggests a distinct paradigm for selective molecular interactions at receptors (the swipe card model): recognition and actuation involve size and shape, but also exploit other processes.Comment: 10 pages, 1 figur

Designing an implementation intervention with the Behaviour Change Wheel for health provider smoking cessation care for Australian Indigenous pregnant women.

BACKGROUND: Indigenous smoking rates are up to 80% among pregnant women: prevalence among pregnant Australian Indigenous women was 45% in 2014, contributing significantly to the health gap for Indigenous Australians. We aimed to develop an implementation intervention to improve smoking cessation care (SCC) for pregnant Indigenous smokers, an outcome to be achieved by training health providers at Aboriginal Medical Services (AMS) in a culturally competent approach, developed collaboratively with AMS. METHOD: The Behaviour Change Wheel (BCW), incorporating the COM-B model (capability, opportunity and motivation for behavioural interventions), provided a framework for the development of the Indigenous Counselling and Nicotine (ICAN) QUIT in Pregnancy implementation intervention at provider and patient levels. We identified evidence-practice gaps through (i) systematic literature reviews, (ii) a national survey of clinicians and (iii) a qualitative study of smoking and quitting with Aboriginal mothers. We followed the three stages recommended in Michie et al.'s "Behaviour Change Wheel" guide. RESULTS: Targets identified for health provider behaviour change included the following: capability (psychological capability, knowledge and skills) by training clinicians in pharmacotherapy to assist women to quit; motivation (optimism) by presenting evidence of effectiveness, and positive testimonials from patients and clinicians; and opportunity (environmental context and resources) by promoting a whole-of-service approach and structuring consultations using a flipchart and prompts. Education and training were selected as the main intervention functions. For health providers, the delivery mode was webinar, to accommodate time and location constraints, bringing the training to the services; for patients, face-to-face consultations were supported by a booklet embedded with videos to improve patients' capability, opportunity and motivation. CONCLUSIONS: The ICAN QUIT in Pregnancy was an intervention to train health providers at Aboriginal Medical Services in how to implement culturally competent evidence-based practice including counselling and nicotine replacement therapy for pregnant patients who smoke. The BCW aided in scientifically and systematically informing this targeted implementation intervention based on the identified gaps in SCC by health providers. Multiple factors impact at systemic, provider, community and individual levels. This process was therefore important for defining the design and intervention components, prior to a conducting a pilot feasibility trial, then leading on to a full clinical trial

Good Vibrations:Locking of Octahedral Tilting in Mixed-Cation Iodide Perovskites for Solar Cells

Metal halide perovskite solar cells have rapidly emerged as leading contenders in photovoltaic technology. Compositions with a mixture of cation species on the A-site show the best performance and have higher stability. However, the underlying fundamentals of such an enhancement are not fully understood. Here, we investigate the local structures and dynamics of mixed A-cation compositions. We show that substitution of low concentrations of smaller cations on the A-site in formamidimium lead iodide (CH(NH2)2PbI3) results in a global "locking" of the PbI6 octahedra tilting. In the locked structure the octahedra tilt at a larger angle but undergo a much reduced amplitude of rocking motion. A key impact of this feature is that the rotational or tumbling motion of the CH(NH2)2+ molecular ion in a locked cage is severely restricted. We discuss the impact of locking on the photovoltaic performance and stability.</p

Improving Care Coordination for Veterans Within VA and Across Healthcare Systems

The VA faces a plethora of care coordination challenges. Many Veterans have multiple conditions and providers, and many get a portion of their care in the community, a number that will only grow as recent legislation expands options for private care. These challenges have spawned new VA initiatives for redesigning care to meet them, described in this supplement in an editorial by Hosenfeld and colleagues. The VA Health Services Research and Development (HSR&D) service, in partnership with VA’s Office of Primary Care, and Office of Community Care, sponsored a State of the Art (SOTA) conference with the goals of (a) summarizing what is known about care coordination relevant to Veterans’ care; (b) identifying care coordination approaches ready for wider dissemination and implementation within VA; and (c) identifying a research agenda and recommendations, as appropriate, for increasing VA’s knowledge and use of evidence-based approaches for coordinating care. Held in March 2018, the SOTA was jointly planned by VA HSR&D and Offices of Primary Care, Community Care, Nursing Services, and Care Management and Social Work, and convened VA and non-VA health services researchers, clinicians, and policy makers. This supplement presents recommendations from the SOTA as well as original research papers on care coordination strategies within VA and between VA and non-VA providers