Coherent Synthesis Research Articles

Direct Synthesis, Characterization and Theoretical Studies of N‐(6‐Amino‐1,3‐dimethyl‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐5‐yl)benzamide Derivatives

AbstractWith the far‐flung importance of uracil and amides in innumerable fields of chemistry and biology, a coherent synthesis that nullifies the use of prodigal reagents, methods and catalysts are hugely accepted. From the present outcomes, we report a highly atom profitable nucleophilic addition reaction of aromatic aldehydes and heterocyclic amines for the generation of amides having an excellent yield and high reproducibility. The main force responsible for the forward reaction is the presence of the nitroso group at the C‐5 position on uracil scaffold, which drives the formation of formidable range products. The conclusive mechanism is based on the dehydrogenation reaction of the carbinolamine product formed during the nucleophilic addition reaction of the aromatic aldehyde with the free heterocyclic amino group to yield the corresponding amides. The synthesized compounds were predicated for biological properties and proved it to be an ideal G protein‐coupled receptor kinase2 (GRK2) inhibitor. Out of all, the compound 3 f showed the most preeminent properties when compared to Paroxetine, studied using molecular docking. At the same time, computed ADME analysis proved them as an ideal drug candidate. Our findings not only prophesize new methods for the synthesis of bioactive‐amides using a cross‐coupling strategy but also demonstrates their novel applications as a human GRK2 inhibitor.

Coherent synthesis of ultrashort pulse fiber laser based on balanced difference method

The output power of the fiber laser can be increased by synthesizing the output beam, but the problem of low output power is caused by the poor ability of controlling bandwidth in the current synthesis research. Therefore, a coherent synthesis method of ultrashort pulse fiber laser based on balanced difference method is proposed. The balance difference of fiber combiner is divided into different modules, including data exchange and acquisition, circuit balancing, phase compensation, etc. Select appropriate ad conversion chip, use Ethernet chip W5300, design data exchange, ensure the normal use of data acquisition function, in the signal preprocessing module, use band-pass filter to filter out unnecessary frequency components, use AD603 to design front-end balancing circuit, design signal separation circuit, separate AC and DC signals, use active phase lock. The phase compensation of each laser is realized by the fixed technology, and the coherent synthesis of ultrashort pulse fiber laser is realized by the fiber combiner. The experimental results show that, compared with the traditional coherent synthesis method, the output power of the coherent combination method based on balanced difference method is about 900 kW, which has higher output power and better control bandwidth. It provides a theoretical basis for practical application.

A Homotopy Approach to Coherent Quantum LQG Control Synthesis Using Discounted Performance Criteria

This paper is concerned with linear-quadratic-Gaussian (LQG) control for a field-mediated feedback connection of a plant and a coherent (measurement-free) controller. The plant and controller are multimode open quantum harmonic oscillators governed by linear quantum stochastic differential equations. The control objective is to make the closed-loop system internally stable and to minimize the infinite-horizon quadratic cost for the plant variables and the controller output subject to quantum physical realizability (PR) constraints. This coherent quantum LQG (CQLQG) control problem, which has been of active research interest for over ten years, does not admit a solution in the form of separation principle and independent Riccati equations known for its classical counterpart. We apply variational techniques to a family of discounted CQLQG control problems parameterized by an effective time horizon. This yields a homotopy algorithm, which is initialized with a PR (but not necessarily stabilizing) controller and aims at a locally optimal stabilizing controller for the original problem in the limit.

Research progress on coherent synthesis of optical frequency comb

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

Statistical finite elements for misspecified models

We present a statistical finite element method for nonlinear, time-dependent phenomena, illustrated in the context of nonlinear internal waves (solitons). We take a Bayesian approach and leverage the finite element method to cast the statistical problem as a nonlinear Gaussian state-space model, updating the solution, in receipt of data, in a filtering framework. The method is applicable to problems across science and engineering for which finite element methods are appropriate. The Korteweg-de Vries equation for solitons is presented because it reflects the necessary complexity while being suitably familiar and succinct for pedagogical purposes. We present two algorithms to implement this method, based on the extended and ensemble Kalman filters, and demonstrate effectiveness with a simulation study and a case study with experimental data. The generality of our approach is demonstrated in SI Appendix, where we present examples from additional nonlinear, time-dependent partial differential equations (Burgers equation, Kuramoto-Sivashinsky equation).

The statistical finite element method (statFEM) for coherent synthesis of observation data and model predictions

The increased availability of observation data from engineering systems in operation poses the question of how to incorporate this data into finite element models. To this end, we propose a novel statistical construction of the finite element method that provides the means of synthesising measurement data and finite element models. The Bayesian statistical framework is adopted to treat all the uncertainties present in the data, the mathematical model and its finite element discretisation. From the outset, we postulate a statistical generating model which additively decomposes data into a finite element, a model misspecification and a noise component. Each of the components may be uncertain and is considered as a random variable with a respective prior probability density. The prior of the finite element component is given by a conventional stochastic forward problem. The prior probabilities of the model misspecification and measurement noise, without loss of generality, are assumed to have a zero-mean and a known covariance structure. Our proposed statistical model is hierarchical in the sense that each of the three random components may depend on one or more non-observable random hyperparameters with their own corresponding probability densities. We use Bayes rule to infer the posterior densities of the three random components and the hyperparameters from their known prior densities and a data dependent likelihood function. Because of the hierarchical structure of our statistical model, Bayes rule is applied on three different levels in turn. On level one, we determine the posterior densities of the finite element component and the true system response using the prior finite element density given by the forward problem and the data likelihood. In this step, approximating the prior finite element density with a multivariate Gaussian distribution allows us to obtain a closed-form expression for the posterior. On the next level, we infer the hyperparameter posterior densities from their respective priors and the marginal likelihood of the first inference problem. These posteriors are sampled numerically using the Markov chain Monte Carlo (MCMC) method. Finally, on level three we use Bayes rule to choose the most suitable finite element model in light of the observed data by computing the respective model posteriors. We demonstrate the application and versatility of statFEM with one and two-dimensional examples.

Temporal Synechism: A Peircean Philosophy of Time

Charles Sanders Peirce is best known as the founder of pragmatism, but the name that he preferred for his overall system of thought was “synechism” because the principle of continuity was its central thesis. He considered time to be the paradigmatic example and often wrote about its various aspects while discussing other topics. This essay draws from many of those widely scattered texts to formulate a distinctively Peircean philosophy of time, incorporating extensive quotations into a comprehensive and coherent synthesis. Time is not an existential subject with past, present, and future as its incompatible predicates, but rather a real law enabling things to possess contrary qualities at its different determinations, and Peirce identifies four classes of such states based on when and how they are realized. Because time is continuous, it is not composed of instants, and even the present is an indefinite lapse during which we are directly aware of constant change. The accomplished past is perpetually growing as the possibilities and conditional necessities of the future are actualized at the present, and the entire universe evolves from being utterly indeterminate toward being absolutely determinate. Nevertheless, time must return into itself even if events are limited to only a portion of it, a paradox that is resolved with the aid of projective geometry. Temporal synechism thus touches on a broad spectrum of philosophical issues including mathematics, phenomenology, logic, and metaphysics.

Quantum optical response of a hybrid optomechanical device embedded with a qubit

We theoretically investigate the optical response in a hybrid quantum optomechanical system consisting of two optically coupled micro-cavities in which a two-level system (qubit) is coupled with a mechanical membrane. The qubit can either be a defect which interacts with the mechanical oscillator via the linear Jaynes–Cummings interaction or a superconducting charge qubit coupled with the mechanical mode via non-linear interaction. We find that coherent perfect transmission (CPT), coherent perfect synthesis (CPS) and optomechanically induced absorption (OMIA) can be generated by suitably adjusting the system parameters. We find that the qubit and its interaction with the mechanical oscillator emerges as a new handle to control these quantum optical properties. The presence of the qubit results in four points where CPT and CPS can be realized compared to the pure optomechanical case (i.e. in the absence of a qubit) where only three points are attained. This shows that the presence of the qubit gives us more flexibility in choosing the appropriate parameter regime where CPT and CPS can be attained and controlled. We also find that OMIA shows three distinct peaks both in the linear and non-linear cases. In the absence of the qubit, OMIA is converted to optomechanically induced transmission (OMIT). An increase in the qubit decay rate also shows a transition from OMIA to OMIT. Our study reveals that the optical response of the non-linear case is relatively rapid and more sensitive compared to the linear case to changes in the system parameters. This demonstrates the potential use of this hybrid system in designing a tunable all-optical switch and photon router, both of which form important elements of a quantum information network.

High-repetition-rate mid-IR femtosecond pulse synthesis from two mid-IR CW QCL-seeded OPAs

Coherent pulse synthesis in the mid-infrared (mid-IR) domain is of great interest to achieve broadband sources from parent pulses, motivated by the advantages of optical frequency properties for molecular spectroscopy and quantum dynamics. We demonstrate a simple mid-IR coherent synthesizer based on two high-repetition-rate optical parametric amplifiers (OPAs) at nJ-level pump energy. The relative carrier envelope phase between the two OPAs was passively stable for a shared continuous wave (CW) quantum cascade laser (QCL) seed. Lastly, we synthesized mid-IR pulses with a duration of 105 fs ranging from 3.4 to 4.0 µm. The scheme demonstrated the potential to obtain broader mid-IR sources by coherent synthesis from multiple CW QCL-seeded OPAs.

Challenges and opportunities in promoting health equity for migrants

Abstract Issue What has to be done to achieve health equity for migrants? International bodies have published many weighty declarations and recommendations to this end, but these need to be ordered and synthesised. A recurring theoretical problem is how to disentangle the health effects of socioeconomic position (SEP) and migrant status, in order to develop policies that effectively address both factors. Description of the problem As part of the Policy Framework for Analysis (PFA) for Work Package 7 of the Joint Action on Health Equity Europe (JAHEE), key policy documents between 2007 and 2018 were reviewed to form a ‘Road Map' from which a coherent synthesis was extracted. The PFA also developed a model for conceptualising the joint influence of SEP and migrant status. What is the relationship between these, and what policy approaches does it imply? Results The main recommendations of the ‘Road Map' were summarised in two categories: ‘upstream' measures (data collection and research, governance, and intersectoral action to tackle social determinants of health) and ‘downstream' ones (access to health services, responsiveness to migrants' needs, and attention for vulnerable groups). In the past, ‘upstream' measures have been unduly neglected. According to the proposed model, migrant status can have both direct effects on health and indirect ones that are mediated via SEP. Along the indirect pathways, migrants may suffer from increased exposure and/or increased vulnerability to health threats associated with low SEP. Lessons A high degree of consensus already exists about health inequities affecting migrants and the measures needed to tackle them. The urgent challenge at the moment is to put these conclusions into practice. To this end, there is little point in tackling socioeconomic inequities and those linked to migration and ethnicity as though they had nothing to do with each other. Key messages The recommendations of international bodies on migrant health from 2007-2018 can be summarized in three ‘upstream’ measures and three ‘downstream’ ones. Promoting health equity for migrants requires breaking down the silos in which work on migration and on SEP has hitherto been carried out.

A problem-oriented systems approach to primary care system development: development and initial testing of the problem-oriented primary care system development record

BackgroundThere is significant global policy interest related to enabling a data-driven approach for evidence-based primary care system development. This paper describes the development and initial testing of a prototype tool (the Problem-Oriented Primary Care System Development Record, or PCSDR) that enables a data-driven and contextualized approach to primary care system development.MethodsThe PCSDR is an electronic record that enables the systematic input, classification, structuring, storage, processing and analysis of different types of data related to the structure, function and performance of primary care systems over time. Data inputted into the PCSDR was coded using the WHO’s PHC-IMPACT framework and classification system. The PCSDR’s functionalities were tested by using a case study of primary care system development in Tajikistan.ResultsTajikistan’s case study demonstrated that the PCSDR is a potentially effective and conceptually-sound tool for the input, classification, structuring and storage of different data types from myriad sources. The PCSDR is therefore a basic data entry and data management system that enables query and analytics functions for health services research and evidence-based primary care system development functions.ConclusionsThe PCSDR is a data system that enables a contextualized approach to evidence-based primary care system development. It represents a coherent and effective synthesis of the fields of primary care system development and performance assessment. The PCSDR enables analysts to leverage primary care performance assessment frameworks for a broad range of functions related to health systems analysis, improvement and the development of learning health systems.

Numerical and experimental study on coherent beam combining using an improved stochastic parallel gradient descent algorithm

The adaptive gradient (AdaGrad) method is an optimization algorithm widely used in the field of artificial intelligence. An adaptive gradient stochastic parallel gradient descent (SPGD) algorithm (AdaSPGD algorithm), combining an AdaGrad algorithm with an SPGD algorithm, is innovatively introduced and implemented in coherent beam synthesis. The performance of a coherent beam combination system utilizing the AdaSPGD method is validated by numerical simulation of straightening static phase aberrations. The results of the simulations indicate that the AdaSPGD algorithm not only can effectively solve the trouble of difficulty in selecting the gain coefficient in the actual beam combining system, but also can accelerate the convergence of the phase control algorithm. Furthermore, the effectiveness of the proposed algorithm is demonstrated by means of the experimental investigation on coherent beam synthesis of a two-channel fiber array. The AdaSPGD algorithm is a satisfactory modification of the conventional SPGD algorithm.

Coherent narrow-linewidth optical frequency synthesis across the optical telecommunication band.

Broadband, coherent narrow-linewidth optical frequency synthesis is of crucial importance in dual-comb interferometric measurement. Here we present a detailed description of the construction and performance characterization of a hertz-level linewidth coherent optical frequency synthesizer across the optical telecommunication band. A narrow-linewidth cavity-stabilized laser at 1565.00 nm is built and coherently transferred through a fiber link with an additional fractional frequency instability of 2.0×10-16 at 1 s averaging time. Broadband, coherent optical frequency synthesis is then achieved by steering one mode of a laser frequency comb with the transferred optical frequency oscillation. By beating with a 1542.14 nm ultra-stable cavity-stabilized laser, the evaluated fractional frequency stability and absolute linewidth of the nearest synthesized optical oscillation are 3.5×10-15 at 1 s averaging time and 1.8 Hz, respectively. According to the ultra-low-noise feature of the utilized laser frequency comb of 4.7×10-17 at 1 s averaging time, the synthesized optical frequency oscillations could maintain the high coherence across the comb's output bandwidth.

Coherent nanofiber array buckling-enabled synthesis of hierarchical layered composites with enhanced strength

Heterogeneous materials possess unique combinations of strength, toughness, and multifunctionality, which are derived from the interplay between the different material constituents. The performance of such materials can be further improved via hierarchical architecting, including down to the nanoscale. Here, a novel hierarchical nanoengineered layered architecture is created by harnessing the coherent buckling of vertically aligned carbon nanotube (CNT) arrays followed by their integration with existing aerospace-grade carbon microfiber polymer-matrix advanced composites. In-plane tensile and interlaminar shear strengths are improved beyond the aerospace composite by ∼30% and 10%, respectively, and also beyond another CNT hierarchical architecture. Multiscale reinforcement mechanisms responsible for the strength enhancement, including nanofiber pullout, bridging, and suppression of delamination, are revealed by scanning electron microscopy and 3D X-ray computed tomography. The ability to design and create scalable, hierarchical materials with characteristic dimensions spanning from the nanoscale to the macroscale opens up a wide new avenue of next-generation advanced materials with enhanced mechanical and multifunctional properties.

The continued need for scientific monographs: an appreciation of John Rothwell's "Control of human voluntary movement".

Here I write a personal assessment of Professor John Rothwell's seminal book, "Control of Human Voluntary Movement". I focus on the second edition published in 1994, reflecting on its importance over the last 25years and explaining why it remains highly relevant for the motor control field to this day. It is to be hoped that a third edition will be written that updates the physiology and unifies it with computational motor control. The book attests to the continuing importance of monographs in science, as they uniquely allow for long-form narrative and coherent synthesis.

Experimental realization of sub-micron patterning using counter-propagating interfering lightsheets (iCLASS)

A light-sheet-based plane-selective sub-micron patterning technique is proposed to fabricate 1D sub-micron patterns with specificity and selectivity. The proposed technique is termed as, interfering coherent light-sheet assisted structure synthesis (iCLASS). The technique uses specialized 2π optical illumination geometry to expose the photoresist film. Counter-propagating light sheets (satisfying phase-matching condition) produce 1D interference pattern with feature size below the diffraction limit. A conventional S1813 photoresist coated on a cleaned glass substrate is exposed to the light-sheets pattern and subsequently, the photoresist film is developed to imprint the sub-micron pattern. AFM study confirms imprinted 1D pattern with a periodicity and feature-size of approximately, λ/2. Analysis show that the light-dose interaction-time (τ exp , τ dev ) plays crucial role in determining the periodicity of 1D sub-micron pattern.

Controllable quantum interference and photon transport in three-mode closed-loop cavity-atom system

In recent years, it has been a hot research topic to study the interaction between atomic ensemble and cavities, and many researches have been done in this regard. In such a system, some atoms are trapped in the cavity, which can be used to study their dynamic characteristics, e.g., the evolution of photon numbers and photon transition. The Jaynes-Cummings model is an important model for studying the dynamic characteristics of the cavity-atom system, which is based on the interaction between a single two-level atom and the cavity field. Recently, coherent photon control in cavity under specific conditions has become an important part of quantum computing and communication. It is worth noting that the tunable photon transmission and all-optical switches based on the cavity have already aroused much interest and have been used in many areas. The quantum information and networks are mostly rooted in complex optical devices, which may show nonreciprocal or asymmetric photon transport. In this paper, we demonstrate that by using an optical closed-loop system the unconventional photon transport can be realized with two mutually perpendicular cavities coupled through external fiber and a two-level atom placed on the intersection. This three-mode system supports two orthogonal propagation directions, that is to say, and the interactions among probe fields are mutually perpendicular. Without ignoring the spontaneous decay of the natural atom, the complex and controllable quantum interference induced by the efficient hybrid interaction of the light, cavity modes, and the atom in such a closed-loop structure can result in a few interesting symmetric and asymmetric photon transport behaviors, i.e. coherent perfect synthesis and coherent perfect reflection. Aside from these compelling properties, the group velocity can also be modulated, i.e., fast and slow light effect. All of these processes can be dynamically controlled by using the probe field phase difference, the tunneling coupling between two cavities and the coupling between the cavity and the atom. Importantly, due to so many advantages, such a tunable scheme can be readily extended to some optical devices, e.g., the switch and the router that is challenging to conventional optical devices.

Back to the Roots? The Applications of Communication Science Theories in Strategic Communication Research

ABSTRACTRecently, the field of strategic communication has been criticized for lacking a coherent theoretical synthesis. Recognizing that strategic communication is a sub-discipline of communication science, we study how the field is anchored in the corpus of established communication theories – including social science, interpretative, and critical approaches. To describe the use, development, and context of communication theories in strategic communication publications, we analyzed all articles published in ten public relations/ corporate communication/ organizational communication/ strategic communication journals over twenty years (N = 4,027). While the vast majority of articles did not refer to one of the 91 communication theories, the share of references to these theories has been increasing. Overall, we found a high diversity of approaches – with considerable differences among journals – indicating a broad discourse. However, we also found a growing relevance of the social science paradigm. We argue that a stronger focus on communication theories may facilitate a consilient synthesis and increase the relevance of the field, academically and practically. We therefore propose to strengthen the communication science perspective in strategic communication.

Joint synthesis of conditionally related multiple outcomes makes better use of data than separate meta-analyses.

BackgroundWhen there are structural relationships between outcomes reported in different trials, separate analyses of each outcome do not provide a single coherent analysis, which is required for decision‐making. For example, trials of intrapartum anti‐bacterial prophylaxis (IAP) to prevent early onset group B streptococcal (EOGBS) disease can report three treatment effects: the effect on bacterial colonisation of the newborn, the effect on EOGBS, and the effect on EOGBS conditional on newborn colonisation. These outcomes are conditionally related, or nested, in a multi‐state model.This paper shows how to exploit these structural relationships, providing a single coherent synthesis of all the available data, while checking to ensure that different sources of evidence are consistent.ResultsOverall, the use of IAP reduces the risk of EOGBS (RR: 0.03; 95% Credible Interval (CrI): 0.002–0.13). Most of the treatment effect is due to the prevention of colonisation in newborns of colonised mothers (RR: 0.08, 95% CrI: 0.04–0.14). Node‐splitting demonstrated that the treatment effect calculated using only direct evidence was consistent with that predicted from the remaining evidence (p = 0.15). The findings accorded with previously published separate meta‐analyses of the different outcomes, once these are re‐analysed correctly accounting for zero cells.ConclusionMultiple outcomes should be synthesised together where possible, taking account of their structural relationships. This generates an internally coherent analysis, suitable for decision making, in which estimates of each of the treatment effects are based on all available evidence (direct and indirect). Separate meta‐analyses of each outcome have none of these properties.

3D Ken Burns effect from a single image

The Ken Burns effect allows animating still images with a virtual camera scan and zoom. Adding parallax, which results in the 3D Ken Burns effect, enables significantly more compelling results. Creating such effects manually is time-consuming and demands sophisticated editing skills. Existing automatic methods, however, require multiple input images from varying viewpoints. In this paper, we introduce a framework that synthesizes the 3D Ken Burns effect from a single image, supporting both a fully automatic mode and an interactive mode with the user controlling the camera. Our framework first leverages a depth prediction pipeline, which estimates scene depth that is suitable for view synthesis tasks. To address the limitations of existing depth estimation methods such as geometric distortions, semantic distortions, and inaccurate depth boundaries, we develop a semantic-aware neural network for depth prediction, couple its estimate with a segmentation-based depth adjustment process, and employ a refinement neural network that facilitates accurate depth predictions at object boundaries. According to this depth estimate, our framework then maps the input image to a point cloud and synthesizes the resulting video frames by rendering the point cloud from the corresponding camera positions. To address disocclusions while maintaining geometrically and temporally coherent synthesis results, we utilize context-aware color- and depth-inpainting to fill in the missing information in the extreme views of the camera path, thus extending the scene geometry of the point cloud. Experiments with a wide variety of image content show that our method enables realistic synthesis results. Our study demonstrates that our system allows users to achieve better results while requiring little effort compared to existing solutions for the 3D Ken Burns effect creation.