Search for interstellar methoxyacetonitrile and cyanoethanol: insights into coupling of cyano- to methanol and ammonia chemistry

As part of an effort to study gas-grain chemical models in star-forming regions as they relate to molecules containing cyanide (–C≡N) groups, we present here a search for the molecules 2-cyanoethanol (OHCH_2CH_2CN) and methoxyacetonitrile (CH_3OCH_2CN) in the galactic center region SgrB2. These species are structural isomers of each other and are targeted to investigate the cross-coupling of pathways emanating from the photolysis products of methanol and ammonia with pathways involving cyano-containing molecules. Methanol and ammonia ices are two of the main repositories of the elements C, O, and N in cold clouds and understanding their link to cyanide chemistry could give important insights into prebiotic molecular evolution. Neither species was positively detected, but the upper limits we determined allow comparison to the general patterns gleaned from chemical models. Our results indicate the need for an expansion of the model networks to better deal with cyanochemistry, in particular with respect to pathways including products of methanol photolysis. In addition to these results, the two main observational routes for detecting new interstellar molecules are discussed. One route is by decreasing detection limits at millimeter wavelength through spatial filtering with interferometric studies at the Atacama Large Millimeter Array (ALMA), and the second is by searching for intense torsional states at THz frequencies using the Herschel Space Observatory. 2-cyanoethanol and methoxyacetonitrile would both be good test beds for exploring the capabilities of ALMA and Herschel in the study of complex interstellar chemistry

Fast Long-Distance Control of Spin Qubits by Photon Assisted Cotunneling

We investigate theoretically the long-distance coupling and spin exchange in an array of quantum dot spin qubits in the presence of microwaves. We find that photon assisted cotunneling is boosted at resonances between photon and energies of virtually occupied excited states and show how to make it spin selective. We identify configurations that enable fast switching and spin echo sequences for efficient and non-local manipulation of spin qubits. We devise configurations in which the near-resonantly boosted cotunneling provides non-local coupling which, up to certain limit, does not diminish with distance between the manipulated dots before it decays weakly with inverse distance.Comment: 17 pages (including 8 pages of Appendices), 2 figure

Force sensing with nanowire cantilevers

Nanometer-scale structures with high aspect ratio such as nanowires and nanotubes combine low mechanical dissipation with high resonance frequencies, making them ideal force transducers and scanning probes in applications requiring the highest sensitivity. Such structures promise record force sensitivities combined with ease of use in scanning probe microscopes. A wide variety of possible material compositions and functionalizations is available, allowing for the sensing of various kinds of forces with optimized sensitivity. In addition, nanowires possess quasi-degenerate mechanical mode doublets, which has allowed the demonstration of sensitive vectorial force and mass detection. These developments have driven researchers to use nanowire cantilevers in various force sensing applications, which include imaging of sample surface topography, detection of optomechanical, electrical, and magnetic forces, and magnetic resonance force microscopy. In this review, we discuss the motivation behind using nanowires as force transducers, explain the methods of force sensing with nanowire cantilevers, and give an overview of the experimental progress and future prospects of the field

Nonlinear motion and mechanical mixing in as-grown GaAs nanowires

We report nonlinear behavior in the motion of driven nanowire cantilevers. The nonlinearity can be described by the Duffing equation and is used to demonstrate mechanical mixing of two distinct excitation frequencies. Furthermore, we demonstrate that the nonlinearity can be used to amplify a signal at a frequency close to the mechanical resonance of the nanowire oscillator. Up to 26 dB of amplitude gain are demonstrated in this way

Torsion–rotation global analysis of the first three torsional states (νt = 0, 1, 2) and terahertz database for methanol

Stimulated by recent THz measurements of the methanol spectrum in one of our laboratories, undertaken in support of NASA programs related to the Herschel Space Observatory (HSO) and the Atacama Large Millimeter Array (ALMA), we have carried out a global analysis of available microwave and high-resolution infrared data for the first three torsional states (νt = 0, 1, 2), and for J values up to 30. This global fit of approximately 5600 frequency measurements and 19 000 Fourier transform far infrared (FTFIR) wavenumber measurements to 119 parameters reaches the estimated experimental measurement accuracy for the FTFIR transitions, and about twice the estimated experimental measurement accuracy for the microwave, submillimeter-wave, and terahertz transitions. The present fit is essentially a continuation of our earlier work, but we have greatly expanded our previous data set and have added a large number of new torsion–rotation interaction terms to the Hamiltonian in our previously used computer program. The results, together with a number of calculated (but unmeasured) transitions, including their line strength, estimated uncertainty, and lower state energy, are made available in the supplementary material as a database formatted to be useful for astronomical searches. Some discussion of several open spectroscopic problems, e.g., (i) an improved notation for the numerous parameters in the torsion–rotation Hamiltonian, (ii) possible causes of the failure to fit frequency measurements to the estimated measurement uncertainty, and (iii) pitfalls to be avoided when intercomparing apparently identical parameters from the internal axis method and the rho axis method are also given

The Uptake and Impact of a Personal Health Record for Patients with Type 2 Diabetes Mellitus in Primary Care: a research protocol for a backward and forward evaluation

A Personal Health Record (PHR) is a promising technology for improving the quality of chronic disease management. Despite the efforts that have been made in a research project to develop a PHR for patients with type 2 diabetes mellitus in primary care (e-Vita), differences have been reported between the number of registered users in the participating primary practices. To gain insight into the factors that influence the implementation of the PHR into daily health care processes and into the possibilities to improve the content, interviews have been conducted with participating primary practice nurses and other stakeholders in the research project. A first impression of the interviews indicated that in many cases, the low impact of the PHR is due to a lack of information about the purpose, content and use of the syste

Impedance model for the polarization-dependent optical absorption of superconducting single-photon detectors

We measured the single-photon detection efficiency of NbN superconducting single photon detectors as a function of the polarization state of the incident light for different wavelengths in the range from 488 nm to 1550 nm. The polarization contrast varies from ~5% at 488 nm to ~30% at 1550 nm, in good agreement with numerical calculations. We use an optical-impedance model to describe the absorption for polarization parallel to the wires of the detector. For lossy NbN films, the absorption can be kept constant by keeping the product of layer thickness and filling factor constant. As a consequence, we find that the maximum possible absorption is independent of filling factor. By illuminating the detector through the substrate, an absorption efficiency of ~70% can be reached for a detector on Si or GaAs, without the need for an optical cavity.Comment: 15 pages, 5 figures, submitted to Journal of Applied Physic

The role of cognition in cost-effectiveness analyses of behavioral interventions

<p>Abstract</p> <p>Background</p> <p>Behavioral interventions typically focus on objective behavioral endpoints like weight loss and smoking cessation. In reality, though, achieving full behavior change is a complex process in which several steps towards success are taken. Any progress in this process may also be considered as a beneficial outcome of the intervention, assuming that this increases the likelihood to achieve successful behavior change eventually. Until recently, there has been little consideration about whether partial behavior change at follow-up should be incorporated in cost-effectiveness analyses (CEAs). The aim of this explorative review is to identify CEAs of behavioral interventions in which cognitive outcome measures of behavior change are analyzed.</p> <p>Methods</p> <p>Data sources were searched for publications before May 2011.</p> <p>Results</p> <p>Twelve studies were found eligible for inclusion. Two different approaches were found: three studies calculated separate incremental cost-effectiveness ratios for cognitive outcome measures, and one study modeled partial behavior change into the final outcome. Both approaches rely on the assumption, be it implicitly or explicitly, that changes in cognitive outcome measures are predictive of future behavior change and may affect CEA outcomes.</p> <p>Conclusion</p> <p>Potential value of cognitive states in CEA, as a way to account for partial behavior change, is to some extent recognized but not (yet) integrated in the field. In conclusion, CEAs should consider, and where appropriate incorporate measures of partial behavior change when reporting effectiveness and hence cost-effectiveness.</p