Inverse Diffusion Theory of Photoacoustics

This paper analyzes the reconstruction of diffusion and absorption parameters in an elliptic equation from knowledge of internal data. In the application of photo-acoustics, the internal data are the amount of thermal energy deposited by high frequency radiation propagating inside a domain of interest. These data are obtained by solving an inverse wave equation, which is well-studied in the literature. We show that knowledge of two internal data based on well-chosen boundary conditions uniquely determines two constitutive parameters in diffusion and Schroedinger equations. Stability of the reconstruction is guaranteed under additional geometric constraints of strict convexity. No geometric constraints are necessary when $2n$ internal data for well-chosen boundary conditions are available, where $n$ is spatial dimension. The set of well-chosen boundary conditions is characterized in terms of appropriate complex geometrical optics (CGO) solutions.Comment: 24 page

Non-equilibrium Magnetization Dynamics in the Fe_8 Single-Molecule Magnet Induced by High-Intensity Microwave Radiation

Resonant microwave radiation applied to a single crystal of the molecular magnet Fe_8 induces dramatic changes in the sample's magnetization. Transitions between excited states are found even though at the nominal system temperature these levels have negligible population. We find evidence that the sample heats significantly when the resonance condition is met. In addition, heating is observed after a short pulse of intense radiation has been turned off, indicating that the spin system is out of equilibrium with the lattice.Comment: Version to appear in Europhysics Letters. Minor changes and updated reference

Quantitative Photo-acoustic Tomography with Partial Data

Photo-acoustic tomography is a newly developed hybrid imaging modality that combines a high-resolution modality with a high-contrast modality. We analyze the reconstruction of diffusion and absorption parameters in an elliptic equation and improve an earlier result of Bal and Uhlmann to the partial date case. We show that the reconstruction can be uniquely determined by the knowledge of 4 internal data based on well-chosen partial boundary conditions. Stability of this reconstruction is ensured if a convexity condition is satisfied. Similar stability result is obtained without this geometric constraint if 4n well-chosen partial boundary conditions are available, where $n$ is the spatial dimension. The set of well-chosen boundary measurements is characterized by some complex geometric optics (CGO) solutions vanishing on a part of the boundary.Comment: arXiv admin note: text overlap with arXiv:0910.250

Co-creation in service assemblages for service innovation : an empirical investigation

Co-creation could enhance service innovation (Perks, Gruber, and Edvardsson, 2012). Despite the research conducted on co-creation, the issue concerning how actors could form service system with high density still needs to be addressed (Michel, Vargo and Lusch, 2008). We conceptualized service system as an assemblage and investigated emergence and dynamic process of assemble and dissemble of service assemblages by drawing on theories of co-creation, affordance, task network and modularity and the notion of assemblage (Delanda, 2006). We developed a framework and empirically examined how to map the competences required for actors in a task network and how capacities could be optimally (re)configured as assemblages (clusters) for value co-creation. We demonstrated that the framework developed could be applied to formation, reformation of service assemblages for design of service offerings enabling optimal value co-creation

The effect of regular physical activity on women's self-confidence levels: An exploratory research

Introduction: It is known that physical activity is good for many diseases such as obesity, heart diseases, various types of cancer, musculoskeletal disorders. Compared to men, women's participation in physical activity is more limited. Physical activity, on the other hand, contributes to both the increase in the quality of life and the socialization of people. In this context, the aim of this study is to determine the self-confidence levels of women who regularly participate in physical activity. Method: In the research, besides the personal information form prepared by the researchers, the self-confidence scale was used. The sample population survey in Turkey Kocaeli province has created 408 women participating regularly in physical activity. In the analysis of the data, arithmetic means, frequency and percentage values were taken. As a result of the normality test, it was seen that it showed a normal distribution. Accordingly, independent sample t-test was used in the analysis of paired groups and one way Anova tests were used in the analysis of multiple groups. Results: As a result of the analysis, no significant difference was found in any sub-dimension according to the marital status variable. Significant differences were observed in the sub-dimensions of the scale according to the variables of income level, physical activity duration, education level and age. Conclusion: It has been observed that as the duration of physical activity increases, the level of self-confidence increases. In addition, it was concluded that age and educational status were directly related to self-confidence, and as education level and age increased, self-confidence increased

Experimental Upper Bound on Superradiance Emission from Mn12 Acetate

We used a Josephson junction as a radiation detector to look for evidence of the emission of electromagnetic radiation during magnetization avalanches in a crystal assembly of Mn_12-Acetate. The crystal assembly exhibits avalanches at several magnetic fields in the temperature range from 1.8 to 2.6 K with durations of the order of 1 ms. Although a recent study shows evidence of electromagnetic radiation bursts during these avalanches [J. Tejada, et al., Appl. Phys. Lett. {\bf 84}, 2373 (2004)], we were unable to detect any significant radiation at well-defined frequencies. A control experiment with external radiation pulses allows us to determine that the energy released as radiation during an avalanche is less than 1 part in 10^4 of the total energy released. In addition, our avalanche data indicates that the magnetization reversal process does not occur uniformly throughout the sample.Comment: 4 RevTeX pages, 3 eps figure

Corticothalamic projections control synchronization in locally coupled bistable thalamic oscillators

Thalamic circuits are able to generate state-dependent oscillations of different frequencies and degrees of synchronization. However, only little is known how synchronous oscillations, like spindle oscillations in the thalamus, are organized in the intact brain. Experimental findings suggest that the simultaneous occurrence of spindle oscillations over widespread territories of the thalamus is due to the corticothalamic projections, as the synchrony is lost in the decorticated thalamus. Here we study the influence of corticothalamic projections on the synchrony in a thalamic network, and uncover the underlying control mechanism, leading to a control method which is applicable in wide range of stochastic driven excitable units.Comment: 4 pages with 4 figures (Color online on p.3-4) include

CoNi/Pt interface roughness probed by nonlinear magneto-optics, x-ray scattering and atomic force microscopy

The crystallographic contribution of the nonlinear magneto-optical response from CoNi/Pt interfaces appears to scale linearly with increasing interface roughness as determined by small angle x-ray scattering and atomic force microscopy. From the magnetic contribution it follows that the increased interface roughness causes the interface moment to turn out of plane while the bulk of the film has an in-plane magnetization

Digital printing of enzymes on textile substrates as functional materials

Recently, there have been significant developments in inkjet printing for applications in various fields such as medicine, biomaterials and sensors. In this research, enzymes like horseradish peroxidase (HRP) and glucose oxidase (GOx) were directly printed by inkjet printer onto flexible textile fabric in predefined patterns to produce a functional material. The functionality of the printed enzymes (bioink) was investigated by chemical reaction after printing fresh and stored bio-ink in a digital printer. The results indicated that these enzymes can be effectively printed individually or in combination, which retains their functionality after printing. Furthermore, HRP was coupled and printed with fluorescent group, the result confirmed that the printed enzyme was still active and retained its functionality despite the printing process. Hence, the digital printing technique can be used as a novel method for producing functional textiles for advanced applications in monitoring health and security