Pilot Study of a Radiation Oncology Telemedicine Platform

Purpose: A pilot study was undertaken to develop an integrated telemedicine platform for radiation oncology at Memorial Sloan-Kettering Cancer Center (MSKCC) and its regional sites. The platform consisted of a computer system with simultaneous display of multiple live data portals including 1) video-conferencing between physicians, 2) radiology, and 3) radiation treatment-planning system (RTPS). Methods and Materials: Two MSKCC regional centers were set up with a widescreen monitor, a dedicated computer, and a web camera with microphone. Each computer ran a Microsoft operating system, utilized video-conferencing software, and connected to the MSKCC Ethernet. This allowed for access to the health information system, radiology (web-based picture archiving and communication systems), RTPS, shared network drives and the internet. Results: After 3 months, physicians at two MSKCC sites were successfully able to implement the proposed telemedicine platform. A small sample of cases (prostate, breast, head and neck, and anal cases) were tested. Radiology images, radiation treatment volumes and plans, and portal images were reviewed. Side-by-side comparison of contouring techniques was performed. The platform allowed physicians to remotely review details of cases efficiently. The interactions of the telemedicine platform improved clinical understanding of each case and often resulted in contouring changes. Conclusion: From this experience, we feel that telemedicine could have a significant clinical impact on patient care, especially at centers with satellite clinics. The future goal of the system will be the development of a virtual tumor board for radiation oncologists. We envision the simultaneous display of multiple clinical components, including face photo, pathology, tumor images/videos of procedures, radiology, RTPS, and anatomy/contouring databases, on one screen surface

Dynamic Jahn-Teller Effect and Colossal Magnetoresistance in La1−xAxMnO3La_{1-x}A_xMnO_3

A model for $La_{1-x}Sr_xMnO_3$ which incorporates the physics of dynamic Jahn-Teller and double-exchange effects is presented and solved via a dynamical mean field approximation. In an intermediate coupling regime the interplay of these two effects is found to reproduce the behavior of the resistivity and magnetic transition temperature observed in $La_{1-x} Sr_x MnO_3$.Comment: 11 pages. Latex. Minor revisions, including improvement of discussion of state with frozen-in lattice distortion. Figures (available from [email protected]) unchange

ReaxFF Reactive Force-Field Modeling of the Triple-Phase Boundary in a Solid Oxide Fuel Cell

In our study, the Ni/YSZ ReaxFF reactive force field was developed by combining the YSZ and Ni/C/H descriptions. ReaxFF reactive molecular dynamics (RMD) were applied to model chemical reactions, diffusion, and other physicochemical processes at the fuel/Ni/YSZ interface. The ReaxFF RMD simulations were performed on the H_2/Ni/YSZ and C_4H_(10)/Ni/YSZ triple-phase boundary (TPB) systems at 1250 and 2000 K, respectively. The simulations indicate amorphization of the Ni surface, partial decohesion (delamination) at the interface, and coking, which have indeed all been observed experimentally. They also allowed us to derive the mechanism of the butane conversion at the Ni/YSZ interface. Many steps of this mechanism are similar to the pyrolysis of butane. The products obtained in our simulations are the same as those in experiment, which indicates that the developed ReaxFF potential properly describes complex physicochemical processes, such as the oxide-ion diffusion, fuel conversion, water formation reaction, coking, and delamination, occurring at the TPB and can be recommended for further computational studies of the fuel/electrode/electrolyte interfaces in a SOFC

On the Fermi Liquid to Polaron Crossover I: General Results

We use analytic techniques and the dynamical mean field method to study the crossover from fermi liquid to polaron behavior in models of electrons interacting with dispersionless classical phonons.Comment: 42 pages, 13 figure

Resonant and Non-Resonant Modulated Amplitude Waves for Binary Bose-Einstein Condensates in Optical Lattices

We consider a system of two Gross-Pitaevskii (GP) equations, in the presence of an optical-lattice (OL) potential, coupled by both nonlinear and linear terms. This system describes a Bose-Einstein condensate (BEC) composed of two different spin states of the same atomic species, which interact linearly through a resonant electromagnetic field. In the absence of the OL, we find plane-wave solutions and examine their stability. In the presence of the OL, we derive a system of amplitude equations for spatially modulated states which are coupled to the periodic potential through the lowest-order subharmonic resonance. We determine this averaged system's equilibria, which represent spatially periodic solutions, and subsequently examine the stability of the corresponding solutions with direct simulations of the coupled GP equations. We find that symmetric (equal-amplitude) and asymmetric (unequal-amplitude) dual-mode resonant states are, respectively, stable and unstable. The unstable states generate periodic oscillations between the two condensate components, which is possible only because of the linear coupling between them. We also find four-mode states, but they are always unstable. Finally, we briefly consider ternary (three-component) condensates.Comment: 16 pages, 4 figures (some of which have multiple parts), to appear in Physica D; streamlined paper; added some references and discussion concerning experimental realizations of this work; higher-resolution copies of a couple figures are available on the version of the document downloadable from http://www.math.gatech.edu/~mason

On the Fermi Liquid to Polaron Crossover II: Double Exchange and the Physics of "Colossal" Magnetoresistance

We use the dynamical mean field method to study a model of electrons Jahn-Teller coupled to localized classical oscillators and ferromagnetically coupled to ``core spins'', which, we argue, contains the essential physics of the ``colossal magnetoresistance'' manganites $Re_{1-x} A_x MnO_3$. We determine the different regimes of the model and present results for the temperature and frequency dependence of the conductivity, the electron spectral function and the root mean square lattice parameter fluctuations. We compare our results to data, and give a qualitative discussion of important physics not included in the calculation. Extensive use is made of results from a companion paper titled: ``On the Fermi Liquid to Polaron Crossover I: General Results''.Comment: 34 pages, 10 figures. Depends on previous paper titled "On the Fermi Liquid to Poalron Crossover I: General Result

Nonperturbative Effects in Gluon Radiation and Photoproduction of Quark Pairs

We introduce a nonperturbative interaction for light-cone fluctuations containing quarks and gluons. The $\bar qq$ interaction squeezes the transverse size of these fluctuations in the photon and one does not need to simulate this effect via effective quark masses. The strength of this interaction is fixed by data. Data on diffractive dissociation of hadrons and photons show that the nonperturbative interaction of gluons is much stronger. We fix the parameters for the nonperturbative quark-gluon interaction by data for diffractive dissociation to large masses (triple-Pomeron regime). This allows us to predict nuclear shadowing for gluons which turns out to be not as strong as perturbative QCD predicts. We expect a delayed onset of gluon shadowing at $x \leq 10^{-2}$ shadowing of quarks. Gluon shadowing turns out to be nearly scale invariant up to virtualities $Q^2\sim 4 GeV^2$ due to presence of a semihard scale characterizing the strong nonperturbative interaction of gluons. We use the same concept to improve our description of gluon bremsstrahlung which is related to the distribution function for a quark-gluon fluctuation and the interaction cross section of a $\bar qqG$ fluctuation with a nucleon. We expect the nonperturbative interaction to suppress dramatically the gluon radiation at small transverse momenta compared to perturbative calculations.Comment: 58 pages of Latex including 11 figures. Shadowing for soft gluons and Fig. 6 are added as well as a few reference

Bose-Einstein Condensation Temperature of Homogenous Weakly Interacting Bose Gas in Variational Perturbation Theory Through Six Loops

We compute the shift of the transition temperature for a homogenous weakly interacting Bose gas in leading order in the scattering length a for given particle density n. Using variational perturbation theory through six loops in a classical three-dimensional scalar field theory, we obtain Delta T_c/T_c = 1.25+/-0.13 a n^(1/3), in agreement with recent Monte-Carlo results.Comment: 4 pages; omega' corrected: final result changes slightly to 1.25+/-0.13; references added; several minor change

Integrating movement ecology with biodiversity research - exploring new avenues to address spatiotemporal biodiversity dynamics

Movement of organisms is one of the key mechanisms shaping biodiversity, e.g. the distribution of genes, individuals and species in space and time. Recent technological and conceptual advances have improved our ability to assess the causes and consequences of individual movement, and led to the emergence of the new field of ‘movement ecology’. Here, we outline how movement ecology can contribute to the broad field of biodiversity research, i.e. the study of processes and patterns of life among and across different scales, from genes to ecosystems, and we propose a conceptual framework linking these hitherto largely separated fields of research. Our framework builds on the concept of movement ecology for individuals, and demonstrates its importance for linking individual organismal movement with biodiversity. First, organismal movements can provide ‘mobile links’ between habitats or ecosystems, thereby connecting resources, genes, and processes among otherwise separate locations. Understanding these mobile links and their impact on biodiversity will be facilitated by movement ecology, because mobile links can be created by different modes of movement (i.e., foraging, dispersal, migration) that relate to different spatiotemporal scales and have differential effects on biodiversity. Second, organismal movements can also mediate coexistence in communities, through ‘equalizing’ and ‘stabilizing’ mechanisms. This novel integrated framework provides a conceptual starting point for a better understanding of biodiversity dynamics in light of individual movement and space-use behavior across spatiotemporal scales. By illustrating this framework with examples, we argue that the integration of movement ecology and biodiversity research will also enhance our ability to conserve diversity at the genetic, species, and ecosystem levels

Reply to: New Meta- and Mega-analyses of Magnetic Resonance Imaging Findings in Schizophrenia: Do They Really Increase Our Knowledge About the Nature of the Disease Process?

This work was supported by National Institute of Biomedical Imaging and Bioengineering Grant No. U54EB020403 (to the ENIGMA consortium)