Synchronization of Active Atomic Clocks via Quantum and Classical Channels

Superradiant lasers based on atomic ensembles exhibiting ultra-narrow optical transitions can emit light of unprecedented spectral purity and may serve as active atomic clocks. We consider two frequency-detuned active atomic clocks, which are coupled in a cascaded setup, i.e. as master & slave lasers, and study the synchronization of the slave to the master clock. In a setup where both atomic ensembles are coupled to a common cavity mode such synchronization phenomena have been predicted by Xu et al. [Phys. Rev. Lett. 113, 154101 (2014)] and experimentally observed by Weiner et al. [arXiv:1503.06464 (2015)]. Here we demonstrate that synchronization still occurs in cascaded setups but exhibits distinctly different phase diagrams. We study the characteristics of synchronization in comparison to the case of coupling through a common cavity. We also consider synchronization through a classical channel where light of the master laser is measured phase sensitively and the slave laser is injection locked by feedback and compare to the results achievable by coupling through quantum channels.Comment: 13 pages, 12 figure

Towards Product Lining Model-Driven Development Code Generators

A code generator systematically transforms compact models to detailed code. Today, code generation is regarded as an integral part of model-driven development (MDD). Despite its relevance, the development of code generators is an inherently complex task and common methodologies and architectures are lacking. Additionally, reuse and extension of existing code generators only exist on individual parts. A systematic development and reuse based on a code generator product line is still in its infancy. Thus, the aim of this paper is to identify the mechanism necessary for a code generator product line by (a) analyzing the common product line development approach and (b) mapping those to a code generator specific infrastructure. As a first step towards realizing a code generator product line infrastructure, we present a component-based implementation approach based on ideas of variability-aware module systems and point out further research challenges.Comment: 6 pages, 1 figure, Proceedings of the 3rd International Conference on Model-Driven Engineering and Software Development, pp. 539-545, Angers, France, SciTePress, 201

Hartree-Fock Many-Body Perturbation Theory for Nuclear Ground-States

We investigate the order-by-order convergence behavior of many-body perturbation theory (MBPT) as a simple and efficient tool to approximate the ground-state energy of closed-shell nuclei. To address the convergence properties directly, we explore perturbative corrections up to 30th order and highlight the role of the partitioning for convergence. The use of a simple Hartree-Fock solution to construct the unperturbed basis leads to a convergent MBPT series for soft interactions, in contrast to, e.g., a harmonic oscillator basis. For larger model spaces and heavier nuclei, where a direct high-order MBPT calculation in not feasible, we perform third-order calculation and compare to advanced ab initio coupled-cluster calculations for the same interactions and model spaces. We demonstrate that third-order MBPT provides ground-state energies for nuclei up into tin isotopic chain that are in excellent agreement with the best available coupled-cluster results at a fraction of the computational cost.Comment: 6 pages, 5 figures, 1 tabl

Proactive Quality Guidance for Model Evolution in Model Libraries

Model evolution in model libraries differs from general model evolution. It limits the scope to the manageable and allows to develop clear concepts, approaches, solutions, and methodologies. Looking at model quality in evolving model libraries, we focus on quality concerns related to reusability. In this paper, we put forward our proactive quality guidance approach for model evolution in model libraries. It uses an editing-time assessment linked to a lightweight quality model, corresponding metrics, and simplified reviews. All of which help to guide model evolution by means of quality gates fostering model reusability.Comment: 10 pages, figures. Appears in Models and Evolution Workshop Proceedings of the ACM/IEEE 16th International Conference on Model Driven Engineering Languages and Systems, Miami, Florida (USA), September 30, 201

Selected topics on the neuroscience of altered perceptions and illusory beliefs

Six neuropsychological topics illustrating altered perceptions and illusory beliefs are explored with particular emphasis on the neurobiological underpinnings of such phenomena. The first five topics are phantom limb, out-of-body experiences including depersonalization and near-death experiences, delusions with an emphasis on the effects of psychedelic drugs, autonomic reflex actions including respiration and heartbeat, and virtual reality. The last topic focuses on three disorders impairing perception and cognition, namely, Anton-Babinski, Charles Bonnet, and Diogenes Syndromes. Many of the related neurobiological mechanisms reflect disturbances of both lower-level and multisensory processing along with specific cortical impairments such as at the temporoparietal junction. The latter has been linked, for example, to out-of-body experiences. Similarly, aberrant neural learning and signaling such as that based on synaptic receptor disturbances show how the interplay between lower-level brain activity and that in the prefrontal cortex contributes to delusions. Specific hypotheses set forth to explain these alterations in perception and cognition are reviewed, such as a remapping theory which depicts cortical reorganization in response to synaptic changes mediated by receptors. The effects of these perceptual/cognitive distortions on experiential pleasure/pain and on adaptability are also explored

Modeling Liver Diseases Using Hepatic Cell Microarrays

Hepatocellular carcinoma (HCC) is an invasive and aggressive cancer of the liver that arises due to chronic cirrhosis. Research into understanding HCC has focused on two-dimensional (2D) and three-dimensional (3D) technologies to simulate the liver microenvironment and use animal models to model how HCC affects the rest of the body. 3D hydrogel models are desired because they can mimic the transport behavior observed in vivo by structurally mimicking the extracellular matrix (ECM) without the ethical concerns of animal models. However, hydrogels can be toxic to cells and require optimal procedures for appropriate handling. In this study, we created 3D models of liver diseases on high-throughput platforms. First, we optimized hydrogel attachment on micropillar chips by coating them with 0.01 w/v % PMA-OD in ethanol. Next, we optimized the protocol for encapsulation of viable Hep3B cells PuraMatrix peptide hydrogel, using a higher seeding density (6 * 106 cells/mL) and two post-print media washes. Then, we established the ability to transduce adenoviruses in situ in encapsulated cells and successfully demonstrated their dose-response behavior towards six compounds. In the second part, we scaled up to using the microwell chip platform and optimized the polymerization of oxidized methacrylated alginate (OMA) for Hep3B encapsulation. First, we plasma-treated microwell chips for 15 minutes at high RF to minimize bubbles. Then, we optimized micro-scale photopolymerization conditions at 45 % methacrylated OMA (OMA-45) and 2 w/v % OMA with 0.05 w/v % PI and reflective background under either low intensity, long duration (2.5 mW/cm2 for 2 minutes) or high intensity, short duration (4.0 mW/cm2, 30 seconds) light by testing cell viability at these conditions. Third, we used these OMA conditions to develop a high-throughput, real-time 3D cell migration assay on a newly engineered 384-pillar plate with sidewalls. We first developed a set of a protocols where out-of-focus cells are removed mean position of cells on a pillar are quantified. Next, we established a delay in growth factor release rate by co-encapsulating growth factors with OMA and methacrylated heparin sulfate sulfate (MH). Finally, we demonstrated collective cell migration occurred toward angiogenic growth factors at 6-10 μm/day over two weeks. These results provide optimized chemistry between hydrogels and polystyrene, show effective hydrogel polymerization techniques for microscale tissue engineering, and yield several methods where scientists can model liver diseases in high-throughput

Modeling Liver Diseases Using Hepatic Cell Microarrays

Hepatocellular carcinoma (HCC) is an invasive and aggressive cancer of the liver that arises due to chronic cirrhosis. Research into understanding HCC has focused on two-dimensional (2D) and three-dimensional (3D) technologies to simulate the liver microenvironment and use animal models to model how HCC affects the rest of the body. 3D hydrogel models are desired because they can mimic the transport behavior observed in vivo by structurally mimicking the extracellular matrix (ECM) without the ethical concerns of animal models. However, hydrogels can be toxic to cells and require optimal procedures for appropriate handling. In this study, we created 3D models of liver diseases on high-throughput platforms. First, we optimized hydrogel attachment on micropillar chips by coating them with 0.01 w/v % PMA-OD in ethanol. Next, we optimized the protocol for encapsulation of viable Hep3B cells PuraMatrix peptide hydrogel, using a higher seeding density (6 * 106 cells/mL) and two post-print media washes. Then, we established the ability to transduce adenoviruses in situ in encapsulated cells and successfully demonstrated their dose-response behavior towards six compounds. In the second part, we scaled up to using the microwell chip platform and optimized the polymerization of oxidized methacrylated alginate (OMA) for Hep3B encapsulation. First, we plasma-treated microwell chips for 15 minutes at high RF to minimize bubbles. Then, we optimized micro-scale photopolymerization conditions at 45 % methacrylated OMA (OMA-45) and 2 w/v % OMA with 0.05 w/v % PI and reflective background under either low intensity, long duration (2.5 mW/cm2 for 2 minutes) or high intensity, short duration (4.0 mW/cm2, 30 seconds) light by testing cell viability at these conditions. Third, we used these OMA conditions to develop a high-throughput, real-time 3D cell migration assay on a newly engineered 384-pillar plate with sidewalls. We first developed a set of a protocols where out-of-focus cells are removed mean position of cells on a pillar are quantified. Next, we established a delay in growth factor release rate by co-encapsulating growth factors with OMA and methacrylated heparin sulfate sulfate (MH). Finally, we demonstrated collective cell migration occurred toward angiogenic growth factors at 6-10 μm/day over two weeks. These results provide optimized chemistry between hydrogels and polystyrene, show effective hydrogel polymerization techniques for microscale tissue engineering, and yield several methods where scientists can model liver diseases in high-throughput

Identify Competencies for Teachers of the World of Transportation in Industrial Arts

It is the purpose of this study to determine and list the competencies needed by teachers of World of Transportation for evaluation by those concerned

International co-movements in recessions

La correlación entre los ciclos económicos depende del estado de la economía y es más alta en recesiones que en expansiones. En este documento sugiero un mecanismo para explicar la causa. Para este propósito, construyo un modelo de ciclo económico real internacional con restricciones de capacidad vinculantes ocasionalmente, que puede explicar las correlaciones cíclicas dependientes del estado entre países en las tasas de crecimiento del PIB. La intuición es que las empresas solo pueden usar su maquinaria hasta un umbral de capacidad. Por lo tanto, en los períodos de auge el crecimiento de una economía individual se puede atenuar cuando la economía alcanza su límite de capacidad. Esto crea una asimetría que puede extenderse a otras economías, creando así correlaciones entre países en función del estado de las tasas de crecimiento del PIB. Empíricamente, compruebo con éxito la presencia de restricciones de capacidad utilizando datos de las economías avanzadas del G-7 en un modelo autorregresivo de umbrales bayesianos (T-VAR). Este hallazgo respalda las limitaciones de capacidad como un canal de transmisión destacado de las asimetrías del PIB entre países en recesiones en comparación con las expansionesBusiness cycle correlations are state-dependent and higher in recessions than in expansions. In this paper, I suggest a mechanism to explain why this is the case. For this purpose, I build an international real business cycle model with occasionally binding constraints on capacity utilization which can account for state-dependent cross-country correlations in GDP growth rates. The intuition is that fi rms can only use their machines up to a capacity ceiling. Therefore, in booms the growth of an individual economy can be dampened when the economy hits its capacity constraint. This creates an asymmetry that can spill-over to other economies, thereby creating state-dependent cross-country correlations in GDP growth rates. Empirically, I successfully test for the presence of capacity constraints using data from the G7 advanced economies in a Bayesian threshold autoregressive (T-VAR) model. This finding supports capacity constraints as a prominent transmission channel of cross-country GDP asymmetries in recessions compared to expansion