Spontaneous photon emission stimulated by two Bose condensates

We show that the phase difference of two overlapping ground state Bose-Einstein condensates can effect the optical spontaneous emission rate of excited atoms. Depending on the phase difference the atom stimulated spontaneous emission rate can vary between zero and the rate corresponding to all the ground state atoms in a single condensate. Besides giving control over spontaneous emission this provides an optical method for detecting the condensate phase difference. It differs from previous methods in that no light fields are applied. Instead the light is spontaneously emitted when excited atoms make a transition into either condensate.Comment: 14 pages, 2 postscript figures, Revtex. Corrections and significant additions in revisio

Deep convolutional neural networks for estimating porous material parameters with ultrasound tomography

We study the feasibility of data based machine learning applied to ultrasound tomography to estimate water-saturated porous material parameters. In this work, the data to train the neural networks is simulated by solving wave propagation in coupled poroviscoelastic-viscoelastic-acoustic media. As the forward model, we consider a high-order discontinuous Galerkin method while deep convolutional neural networks are used to solve the parameter estimation problem. In the numerical experiment, we estimate the material porosity and tortuosity while the remaining parameters which are of less interest are successfully marginalized in the neural networks-based inversion. Computational examples confirms the feasibility and accuracy of this approach

Tolerating the intolerable: Flash smelting of copper and the construction of technological constraints

The history of Outokumpu flash furnace and the construction of electricity constraints.</p

Overcoming Scarcities Through Innovation: What Do Technologists Do When Faced With Constraints?

The question that still divides many debates about sustainability is the possibility of technological substitution of scarce natural resources. While there is considerable debate among economists whether technology can mitigate scarcities through development of substitutes, there is little actual research on the mechanisms and limitations of this substitution process. In this study, I seek to build a bridge between scarcity and innovation literatures to study when technologists decide to develop technological substitutes. My starting point is the theory of technology as a recombination of existing mental and physical components. Combining this theory with modern scarcity literature that differentiates between absolute, relative, and quasi-scarcities yields a more nuanced framework for understanding both different types of scarcities, and how technologists decide whether or not to develop or adopt technological substitutes. This improves our understanding of the possibilities — and limitations — of scarcity-induced innovation. I then illustrate the use of this framework with two brief historical case studies about constraint-induced innovation. I conclude that the mainstream economic practice of assuming that substitution will occur automatically, even in cases of absolute scarcity, may hide extremely important phenomena from discussion and debate behind a veil of circular reasoning.</p

The Role of Attorney Fee Shifting in Public Interest Litigation

BACKGROUND: Brain tissue segmentation of white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) are important in neuroradiological applications. Quantitative Mri (qMRI) allows segmentation based on physical tissue properties, and the dependencies on MR scanner settings are removed. Brain tissue groups into clusters in the three dimensional space formed by the qMRI parameters R1, R2 and PD, and partial volume voxels are intermediate in this space. The qMRI parameters, however, depend on the main magnetic field strength. Therefore, longitudinal studies can be seriously limited by system upgrades. The aim of this work was to apply one recently described brain tissue segmentation method, based on qMRI, at both 1.5 T and 3.0 T field strengths, and to investigate similarities and differences. METHODS: In vivo qMRI measurements were performed on 10 healthy subjects using both 1.5 T and 3.0 T MR scanners. The brain tissue segmentation method was applied for both 1.5 T and 3.0 T and volumes of WM, GM, CSF and brain parenchymal fraction (BPF) were calculated on both field strengths. Repeatability was calculated for each scanner and a General Linear Model was used to examine the effect of field strength. Voxel-wise t-tests were also performed to evaluate regional differences. RESULTS: Statistically significant differences were found between 1.5 T and 3.0 T for WM, GM, CSF and BPF (p<0.001). Analyses of main effects showed that WM was underestimated, while GM and CSF were overestimated on 1.5 T compared to 3.0 T. The mean differences between 1.5 T and 3.0 T were -66 mL WM, 40 mL GM, 29 mL CSF and -1.99% BPF. Voxel-wise t-tests revealed regional differences of WM and GM in deep brain structures, cerebellum and brain stem. CONCLUSIONS: Most of the brain was identically classified at the two field strengths, although some regional differences were observed

Thermodynamics of Quasi Conformal Theories From Gauge/Gravity Duality

We use gauge/gravity duality to study the thermodynamics of a generic almost conformal theory, specified by its beta function. Three different phases are identified, a high temperature phase of massless partons, an intermediate quasi-conformal phase and a low temperature confining phase. The limit of a theory with infrared fixed point, in which the coupling does not run to infinity, is also studied. The transitions between the phases are of first order or continuous, depending on the parameters of the beta function. The results presented follow from gauge/gravity duality; no specific boundary theory is assumed, only its beta function.Comment: 17 pages, 13 figures

Professional carers’ experiences of working with reablement

Purpose. The purpose of this study was to provide knowledge about professional carers’ experiences of working with everyday activities within the framework of reablement. Method. In this explorative study focus group discussions were utilised as a method for collecting data. There was a total of twenty-five participants across five focus groups. The participants were professional carers working in home care services across two municipalities. A grounded theory approach was used to analyse the data. Results. The findings indicate that the professional carers have experienced working with reablement as exciting and challenging. Reablement has led to a change in how they work to ensure participation for service recipients. Implementing this change has led to having to negotiate dilemmas. However, the professional carers experienced it as a privilege to play a part in service recipients’ achievements. Conclusion. Reablement can be a framework that allows for an increased focus on participation in everyday activities. Due to a shift from providing assistance to enabling participation, reablement was perceived as a positive framework for increasing independence for home care service users. Reablement can also be a framework for increased collaboration between professional carers and their service recipients. However, there is a need for focusing on how professional carers' can be better prepared for the dilemmas they encountered

Fast convergence to equilibrium for long-chain polymer melts using a MD/continuum hybrid method

Effective and fast convergence toward an equilibrium state for long-chain polymer melts is realized by a hybrid method coupling molecular dynamics and the elastic continuum. The required simulation time to achieve the equilibrium state is reduced drastically compared with conventional equilibration methods. The polymers move on a wide range of the energy landscape due to large-scale fluctuation generated by the elastic continuum. A variety of chain structures is generated in the polymer melt which results in the fast convergence to the equilibrium state.Comment: 13 page

Finite-size effects in dynamics of zero-range processes

The finite-size effects prominent in zero-range processes exhibiting a condensation transition are studied by using continuous-time Monte Carlo simulations. We observe that, well above the thermodynamic critical point, both static and dynamic properties display fluid-like behavior up to a density {\rho}c (L), which is the finite-size counterpart of the critical density {\rho}c = {\rho}c (L \rightarrow \infty). We determine this density from the cross-over behavior of the average size of the largest cluster. We then show that several dynamical characteristics undergo a qualitative change at this density. In particular, the size distribution of the largest cluster at the moment of relocation, the persistence properties of the largest cluster and correlations in its motion are studied.Comment: http://pre.aps.org/abstract/PRE/v82/i3/e03111