bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibin Inactivation in Female Mice Leads to Elevated FSH Levels, Ovarian Overstimulation, and Pregnancy Loss
Authors: Walton Kelly L , Goney Monica P , Peppas Zoe , Stringer Jessica M , Winship Amy , Hutt Karla , Goodchild Georgia , Maskey Shreya , Chan Karen L , Brûlé Emilie , Bernard Daniel J , Stocker William A , Harrison Craig A
Published: March 2022

Inhibins are members of the transforming growth factor-β family, composed of a common α-subunit disulfide-linked to 1 of 2 β-subunits (βA in inhibin A or βB in inhibin B). Gonadal-derived inhibin A and B act in an endocrine manner to suppress the synthesis of follicle-stimulating hormone (FSH) by pituitary gonadotrope cells. Roles for inhibins beyond the pituitary, however, have proven difficult to delineate because deletion of the inhibin α-subunit gene (Inha) results in unconstrained expression of activin A and activin B (homodimers of inhibin β-subunits), which contribute to gonadal tumorigenesis and lethal cachectic wasting. Here, we generated mice with a single point mutation (Arg233Ala) in Inha that prevents proteolytic processing and the formation of bioactive inhibin. In vitro, this mutation blocked inhibin maturation and bioactivity, without perturbing activin production. Serum FSH levels were elevated 2- to 3-fold in InhaR233A/R233A mice due to the loss of negative feedback from inhibins, but no pathological increase in circulating activins was observed. While inactivation of inhibin A and B had no discernible effect on male reproduction, female InhaR233A/R233A mice had increased FSH-dependent follicle development and enhanced natural ovulation rates. Nevertheless, inhibin inactivation resulted in significant embryo-fetal resorptions and severe subfertility and was associated with disrupted maternal ovarian function. Intriguingly, heterozygous Inha+/R233A females had significantly enhanced fecundity, relative to wild-type littermates. These studies have revealed novel effects of inhibins in the establishment and maintenance of pregnancy and demonstrated that partial inactivation of inhibin A/B is an attractive approach for enhancing female fertility.
British Travelers to the Mines of Rio de la Plata and Chile in the Aftermath of the Financial Crisis of 1825–26: Political Economy and Questions of Observation
Authors: Cooper Brian P.
Published: March 2022

This article focuses on work published by British travelers to Chile and Rio de la Plata who inspected mining association holdings in the region in the wake of the financial crisis of 1825–26. The travelers sought to determine whether it proved prudent to continue to direct British men, money, know-how, and equipment to the mines. They drew on the work of political economists to help establish the credibility of their observations and accounts, particularly with respect to the relationship between the lack of the division of labor and population in La Plata and Chile and prospects for future speculative investments in the mines. However, while political economists blamed the financial crisis on the uncertainty generated by the actions of the Bank of England and private banks, the commercial travelers focused on other sources of observational and representational error: principal-agent problems in the joint-stock mining associations, and the travelers' ignorance and prejudices about the region.
Two Types of Travelers in the History of the Transmission of Western Economic Knowledge in Late Qing and Early Republican China
Authors: Chao Hsiang-Ke
Published: March 2022

The history of the transmission of Western knowledge to China—Western Learning or Xixue—usually revolves around travelers. What is unmentioned, however, is that the identity of the two types of Chinese travelers of economic knowledge evolved throughout the Western Learning Movement. One-way travelers introduced political economy as a means to improve institutions and statecraft. First-generation Chinese students overseas continued to promote economics as a science capable of enriching a nation's wealth but focused on the theoretical aspect. The second-generation students became economics professionals, who were primarily concerned with practical economic problems and created a scene of practical pluralism of economics during the interwar period. Not all travelers were of the same quality. To judge between the good and bad traveler, further criteria are required. It can be said that good travelers may have a correct understanding of Western theory, and that their translations are faithful, yielding the knowledge they transmitted with integrity. But travelers confronted the problems of trading off faithful and significant knowledge transmissions. Such conundrums can be explained by distinguishing between their distinct conceptions of economics—economics as statecraft, as science, and as a discipline characterized by its practical pluralism—concerning travelers' ideas of solving China's practical economic problems in different periods.
Wolf Ladejinsky: Field Trips for a Democratic Countryside
Authors: D'Onofrio Federico , Tyler Hannah
Published: March 2022

By looking at the life, travels, and work of Wolf Ladejinsky, one of the leading American experts and advisers on agrarian reforms in Asia during the postwar era, this article sheds light on the practices of development experts. Ladejinsky's work shows how the postwar period saw the emergence of a new kind of traveling economist whose task was to engineer and assess the implementation of modernization programs. In particular, the article analyzes the role of field trips in the career of Ladejinsky across Asia. The task of traveling experts was complicated. Ladejinsky's agenda was clear and his goals predetermined but they had to be adapted to different national and international frameworks. Adaptation had two sides: on the one hand, it meant fixing certain elements of the land reform plan, such as the maximum size of landowners' estates, according to local agricultural conditions; on the other, adaptation consisted of a form of institutional engineering, to harness political will, popular support, and bureaucratic structures for land reform. He developed, therefore, an array of methodological suggestions to collect relevant information during short visits.
Evolution of plasticity: metabolic compensation for fluctuating energy demands at the origin of life
Authors: Seebacher Frank , Beaman Julian
Published: March 2022

Phenotypic plasticity of physiological functions enables rapid responses to changing environments and may thereby increase the resilience of organisms to environmental change. Here, we argue that the principal hallmarks of life itself, self-replication and maintenance, are contingent on the plasticity of metabolic processes (‘metabolic plasticity’). It is likely that the Last Universal Common Ancestor (LUCA), 4 billion years ago, already possessed energy-sensing molecules that could adjust energy (ATP) production to meet demand. The earliest manifestation of metabolic plasticity, switching cells from growth and storage (anabolism) to breakdown and ATP production (catabolism), coincides with the advent of Darwinian evolution. Darwinian evolution depends on reliable translation of information from information-carrying molecules, and on cell genealogy where information is accurately passed between cell generations. Both of these processes create fluctuating energy demands that necessitate metabolic plasticity to facilitate replication of genetic material and (proto)cell division. We propose that LUCA possessed rudimentary forms of these capabilities. Since LUCA, metabolic networks have increased in complexity. Generalist founder enzymes formed the basis of many derived networks, and complexity arose partly by recruiting novel pathways from the untapped pool of reactions that are present in cells but do not have current physiological functions (the so-called ‘underground metabolism’). Complexity may thereby be specific to environmental contexts and phylogenetic lineages. We suggest that a Boolean network analysis could be useful to model the transition of metabolic networks over evolutionary time. Network analyses can be effective in modelling phenotypic plasticity in metabolic functions for different phylogenetic groups because they incorporate actual biochemical regulators that can be updated as new empirical insights are gained.
Mito-FUNCAT-FACS reveals cellular heterogeneity in mitochondrial translation
Authors: Kimura Yusuke , Saito Hironori , Osaki Tatsuya , Ikegami Yasuhiro , Wakigawa Taisei , Ikeuchi Yoshiho , Iwasaki Shintaro
Published: March 2022

Mitochondria possess their own genome that encodes components of oxidative phosphorylation (OXPHOS) complexes, and mitochondrial ribosomes within the organelle translate the mRNAs expressed from the mitochondrial genome. Given the differential OXPHOS activity observed in diverse cell types, cell growth conditions, and other circumstances, cellular heterogeneity in mitochondrial translation can be expected. Although individual protein products translated in mitochondria have been monitored, the lack of techniques that address the variation in overall mitochondrial protein synthesis in cell populations poses analytic challenges. Here, we adapted mitochondrial-specific fluorescent noncanonical amino acid tagging (FUNCAT) for use with fluorescence-activated cell sorting (FACS) and developed mito-FUNCAT-FACS. The click chemistry-compatible methionine analog L-homopropargylglycine (HPG) enabled the metabolic labeling of newly synthesized proteins. In the presence of cytosolic translation inhibitors, HPG was selectively incorporated into mitochondrial nascent proteins and conjugated to fluorophores via the click reaction (mito-FUNCAT). The application of in situ mito-FUNCAT to flow cytometry allowed us to separate changes in net mitochondrial translation activity from those of the organelle mass and detect variations in mitochondrial translation in cancer cells. Our approach provides a useful methodology for examining mitochondrial protein synthesis in individual cells.
Clinicians as Leaders: Impact and Challenges
Authors: Khan Rehan Nasir , Aziz Ayesha , Siddiqui Nadeem Ahmed
Published: March 2022

Healthcare has always been a complex system phenomenon which needs accountability from the leading clinical and management roles. Adequate and competent leadership is recognized as a driving point for a successful healthcare division. Medical professionals taking charge for quality improvement are well placed yet the style to deliver their leadership qualities bears a massive significance. While exceptional clinical prowess is of tremendous importance, harmonious teamwork, inefficiency reduction and patient communication and safety lead to noteworthy health management outcomes. Explores not explains the importance of leadership, qualities and styles of a leader, various leadership theories, the impact of leadership in medical education and the current issues related to medical leadership.

doi: https://doi.org/10.12669/pjms.38.4.4918

How to cite this:Khan RN, Aziz A, Siddiqui NA. Clinicians as Leaders: Impact and Challenges. Pak J Med Sci. 2022;38(4):---------.  doi: https://doi.org/10.12669/pjms.38.4.4918

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
In-air Hand Gesture Signature Recognition: An iHGS Database Acquisition Protocol
Authors: Khoh Wee How , Pang Ying Han , Yap Hui Yen
Published: March 2022

Background

With the advances in current technology, hand gesture recognition has gained considerable attention. It has been extended to recognize more distinctive movements, such as a signature, in human-computer interaction (HCI) which enables the computer to identify a person in a non-contact acquisition environment. This application is known as in-air hand gesture signature recognition. To our knowledge, there are no publicly accessible databases and no detailed descriptions of the acquisitional protocol in this domain.

Methods

This paper aims to demonstrate the procedure for collecting the in-air hand gesture signature’s database. This database is disseminated as a reference database in the relevant field for evaluation purposes. The database is constructed from the signatures of 100 volunteer participants, who contributed their signatures in two different sessions. Each session provided 10 genuine samples enrolled using a Microsoft Kinect sensor camera to generate a genuine dataset. In addition, a forgery dataset was also collected by imitating the genuine samples. For evaluation, each sample was preprocessed with hand localization and predictive hand segmentation algorithms to extract the hand region. Then, several vector-based features were extracted.

Results

In this work, classification performance analysis and system robustness analysis were carried out. In the classification analysis, a multiclass Support Vector Machine (SVM) was employed to classify the samples and 97.43% accuracy was achieved; while the system robustness analysis demonstrated low error rates of 2.41% and 5.07% in random forgery and skilled forgery attacks, respectively.

Conclusions

These findings indicate that hand gesture signature is not only feasible for human classification, but its properties are also robust against forgery attacks.
The human conscience between witnessing and discernment: Heidegger, Ricoeur and beyond
Authors: Grzywacz Robert
Published: March 2022

The paper deals with the problem of human conscience as an attentional mode of being that effectuates an original capacity for discernment. Such an undertaking, after the necessary terminological and phenomenological clarifications, requires one to cope with its specific background, especially the critique of the moral worldview and the postmetaphysical setting of contemporary thinking. Taking into consideration the Heideggerian view of the matter, I reflect on the doubts Ricoeur addressed to the former, and take advantage of  Ricoeur’s early philosophy to reinterpret and develop his own stance as expounded in Oneself as Another. His later work on ideology and utopia may contribute to helping to establish some criteria for the functioning of the conscience.
Valoración ética de la Modernidad según Alasdair MacIntyre
Authors: Montoya Camacho Jorge Martín
Published: March 2022

¿Puede ser comprendida la moralidad aisladamente de los órdenes sociales, culturales, políticos y económicos en los que surge y se desarrolla? ¿El interés intelectual por la moralidad de nuestro tiempo requiere algo más que el análisis de teorías éticas? Las respuestas de Alasdair MacIntyre a estas preguntas se muestran a través del trabajo de toda una vida, en la que ha desarrollado un análisis ético de la Modernidad. El libro «Valoración ética de la modernidad según Alasdair MacIntyre», de Hernando José Bello Rodríguez y José Manuel Giménez Amaya, expone el desarrollo de tal análisis, llevado a cabo por el filósofo escocés en el marco de sus ideas que van desde la publicación de su obra After Virtue, hasta la reciente aparición de Ethics in Conflicts of Modernity.
Uczniowie Szkoły Głównej Koronnej 1780-1795
Authors: Zwolska Halina
Published: March 2022

Despite numerous studies on the history of the Jagiellonian University during the existence of the Principal School of the Realm, detailed biographical and prosopographical studies on the student community have been lacking so far. Research on Kraków university students has a long tradition and dates back to the 19th century. Data on students and professors from the period 1364-1780 are collected in the database Corpus Academicum Cracoviense (https://cac.historia.uj.edu.pl/). Data on students from the second half of the 19th century until Poland regained its independence is collected in a multi-volume publication Corpus studiosorum Universitatis Iagellonicae 1850/51-1917/18. The present book fills a serious gap. It is a catalogue of students from the years 1780-1795 and has an exceptional character. For other periods we have a much better source base. For the Middle Ages and Early Modern Era it is a series of matriculation books. For new times, it is the annually kept enrollment cards and student catalogues. For the period of the Principal School of the Realm there is no uniform documentation of this type. The student community has to be reconstructed on the basis of very diverse and fragmentarily preserved, incomplete sources. These include catalogues of colleges and seminaries, lists of students for particular years, certificates of attendance at lectures or of obtaining degrees, minutes of examinations, oaths of candidates for teachers (submissions), account books, visitors’ reports and others.
The Ukrainian Transformation Initiatives of Eastern Partnership
Authors: Malskyy Markiyan
Published: March 2022

The new problems and challenges facing the EU’s Eastern Partnership Initiative are generated by the dynamism and predictability of political events in Central and Eastern Europe. The European Union is implementing this project by combining two interrelated approaches – intensive bilateral cooperation between partner countries and the EU and the multilateral interaction of participants within the framework of regional programmes. Both sides (the Council of Europe and the partner countries) – mutually taking into account the positions and proposals of the Eastern Partnership participants – propose some new approaches and mechanisms for the project’s functioning. In the list of new initiatives, a special place is occupied by the “revolutionary format” of cooperation with the “European Union – Associated Trio”, proposed by Ukraine, Georgia and Moldova. This initiative is becoming the subject of extensive expert and political discussions in the European Union and raises the question of the future of the Eastern Partnership.
Evolution of Relations Between the Republic of Moldova and the European Union in the Context of Eastern Partnership (2009–2021): Main Directions
Authors: Stercul Natalia
Published: March 2022

The participation of the Republic of Moldova in the Eastern Partnership (EaP) platform has enabled Moldova to make significant progress in country’s development over the past decade. The enhancing and deepening relationships with the EaP countries and the European Union (EU), along with the implementation of diverse programs and initiatives drawn up by the EU within the framework of the Eastern Neighborhood Policy has brought tangible results and benefits. The signing of the Association Agreement with the EU has become an important integral part of the constructive political dialogue between the Republic of Moldova and the EU, which covers all cooperation areas in their interest. The creation of the DCFTA had a favorable impact on the increase in Moldovan exports to the EU countries, trade in services, competitiveness of Moldovan products, and it intensified trade and economic relations between the parties. The visa liberalization regime and the technical and financial support from the EU have created a number of advantages for the Republic Moldova and its citizens.The development of relationships between the Republic of Moldova and the EU has been characterized by ups and downs – from the “success story” of the Eastern Partnership to a peroid of crisis and stagnation. The difficulties of cooperation were due to internal political crises, inconsistency of the government’s actions and a low level of democratic development coupled with a high level of corruption of Moldovan officials. The new stage of development has emerged with the coming to power in Moldova in 2020–2021 of pro-European forces. This new phase will be based on pragmatic dialogue and the acceleration of integration processes. The EU’s commitment to strengthening the political association and economic integration of the Republic of Moldova with the European Union continues to be a strong foundation for internal fundamental transformations, state development and modernization of the country.
Application of the EU-Georgia Association Agreement by the Georgian Judiciary: A Role Unplayed by the Inert and Under-Reformed Courts
Authors: Lapiashvili Nino
Published: March 2022

This paper analyses the association implementation reports for the purposes of tracking Brussels’ perception of judicial reform in Georgia. It argues that since the signing of the Association Agreement (AA), as the initial excitement dissipated the European Union gradually became more critical and open-eyed to the long-standing problem of the underreformed judiciary, which is among the main obstacles to consolidating democratic institutions in the country. In addition, the case law of the common courts (Supreme Court of Georgia and Appellate Court of Georgia) as well as of the Constitutional Court of Georgia is being reviewed in order to demonstrate that most of the attempts of either litigants, or the authors of amicus curie or the lower courts aimed at facilitation of the effective implementation of Association Agreement via the ‘pro-European’ judicial activism had been neglected and ignored by the Georgian judiciary ranking superior in the hierarchy. In conclusion, the article does not maintain that there is a direct link between the apparently blind eye turned by Brussels towards the Georgian Judiciary and the total inertness of the judicial branch, discussed in the second chapter, in promoting the implementation of the AA via its application during the decision-making process . However, it provides a context for the stakeholders that is necessary enough to remain focused on reasons that might cause dramatic democratic backsliding in the future.
When Is Product Personalization Profit-Enhancing? A Behavior-Based Discrimination Model
Authors: Laussel Didier , Resende Joana
Published: March 2022

This paper investigates duopoly competition when horizontally differentiated firms are able to make personalized product-price offers to returning customers, within a behavior-based discrimination model. In the second period, firms can profile old customers according to their preferences, selling them targeted products at personalized prices. Product-price personalization (PP) allows firms to retain all old customers, eliminating second-period customer poaching. The overall profit effects of PP are shown to be ambiguous. In the second period, PP improves the matching between customers’ preferences and firms’ offers, but firms do not make any revenues in the rival’s turf. In the Bertrand outcome, second-period profits only increase for both firms if the size of their old turfs are not too different or initial products are not too differentiated. However, the additional second-period profits may be offset by lower first-period profits. PP is likely to increase firms’ overall discounted profits when consumers’ (firms’) discount factor is low (high) and firms’ initial products are exogenous and sufficiently different. When the location of initial products is endogenous, profits are hurt because of an additional location (strategic) effect aggravating head-to-head competition in the first period. Likewise, when a fraction of active consumers conceals their identity, PP increases second-period profits at the cost of aggressive first-period price competition. Finally, we show that the room for profitable PP enlarges considerably if firms rely on PP as an effective device to sustain tacit collusive outcomes, with firms credibly threatening to respond to first-period price deviations with second-period aggressive relocations of their standard products.

This paper was accepted by Matthew Shum, marketing.

Funding: D. Laussel gratefully acknowledges support by the French National Research Agency [Grant ANR-17-EURE-0020] and the Excellence Initiative of Aix-Marseille University [Grant A*MIDEX]. J. Resende was supported by Portuguese public funds [Project Reference NORTE-01-0145-FEDER-028540] and through FCT (Fundação para a Ciência e a Tecnologia) [Project Reference POCI-01-0145-FEDER-006890].

Supplemental Material: The online appendix is available at https://doi.org/10.1287/mnsc.2022.4298 .
Formulaic Expressions for Foreign Language Learning and Teaching
Authors: Schmale Günter
Published: March 2022

Foreign language teaching experts unanimously insist on the necessity of acquiring formulaic expressions in order to communicate successfully in the target language. However, many of the treatises in favour of phraseme use, including semantically non-compositional idiomatic expressions, by foreign language learners seem to be marked by an insufficient depth of reflection as to applied linguistic, methodological, and phraseodidactic[1] criteria. The present contribution therefore aims at a differentiated treatment of prefabricated communicative constructions, starting out from an extended definition and classification and by discussing the pros and cons of phraseme acquisition. These considerations will lead to the delimitation of formulaic language fundamental for an operative foreign language competence (routine formulae, collocations and “constructions”) as opposed to those types of phrasemes which are not essential or even inappropriate for non-native speakers.

 

[1] A term as a direct translation from German Phraseodidaktik, employed in English language publications of non-native researchers, e. g. Gonzalez-Rey (2018), which we decided to adopt here for practical reasons.
Geschlechtsübergreifende Personenbezeichnungen in wissenschaftlichen Zeitschriftenartikeln
Authors: Toonen Jaron
Published: March 2022

This study, based on a corpus of 20 Dutch and 20 German scientific journal articles, looks at how authors of German and Dutch research papers use nouns referring to persons. This investi-gation shows that although the two West Germanic languages are typologically similar due to their geographic proximity the two languages can vary a lot in terms of the abstraction (e. g. Lehrkräfte, Personen; leerkrachten, personen) and specification (e. g. Lehrerinnen und Lehrer; leraressen en leraren) of both grammatical gender and biological sex in academic articles. As a result it can be observed that Dutch authors prefer generic masculine personal nous whereas German authors tend to use more alternative forms, especially in recent times. The result contributes not only to a deeper understanding of personal nouns in academic articles but also to a clearer understanding of where and why there are differences between German and Dutch.
Computational Fluid Dynamics analysis on the Reusable Launch Vehicle
Authors: PRASAD G.
Published: March 2022

Computational fluid dynamics and Additive manufacturing are the two important and recently used technique in the reusable launch vehicle. In this article the design and flow simulation of the re-entry capsule has been performed using Computational Fluid Dynamics in order to optimize the suitable re-entry capsule design. Computational fluid dynamics can be used to simulate the real time supersonic flow during re-entry which helps in predicting the important characteristics during the formation of shock waves. The study considered Mach 5 conditions and an altitude of 5km. In addition, the formation of shock waves was delayed in the present studies compared to previous work. It should be noted that the current aerospace industry uses the advantage of additive production in prototyping to test re-entry launch vehicles.
Influence of Lubricants Degradation Level over Tribological Properties
Authors: RADULESCU Alexandru Valentin , RADULESCU Irina , PETRESCU Florin
Published: March 2022

The paper presents the tribological aspects of the solid-fluid interaction, in order to develop an easy to use fast diagnoses method for the liquid lubricants, with minimal investments and a high precision level. The test program, using a TIMKEN equipment, analyzed the influence of the lubricant state of degradation, considering the tribological behavior of the friction couple during the working time. Two different lubricants (15W-40 and H46-EPS/1) were tested, in both fresh and used state. Tests were performed using three values of the normal load and two sliding velocities. During the tests, the wear trace (width and depth) was measured. Finally, pictures of the damage area were obtained with NEOPHOT 21 metallographic microscope. Spectrometric analysis was performed to identify the geometry, shape and concentration of the wear particles for fresh and used lubricants. The main result of this research is an altenative method of evaluating and quantifying the wear degree and lubricants durability.
Avalanche risk analysis using airborne LiDAR data
Authors: GRIGORAS Georgiana , VIZIREANU Ioana , URITESCU Bogdan , CALCAN Andreea
Published: March 2022

Natural and man-made disasters are a justified concern causing life-threats damages, affects existing budgets or disrupts national economic and social development plans. In this paper, a digital terrain model (DTM) and a geographic information system (GIS) are used to identify areas with a high risk of avalanches in the Râmeț mountain area of Alba County. Avalanches are the result of a complex interaction between terrain, weather conditions and snow cover characteristics. The most important factor among those listed is the terrain, being the only constant parameter over time. Therefore, the present study focused in particular on the determination of topographic parameters and the realization of a digital terrain model with a resolution of 0.5 m, which allows the small-scale identification of slope angle variations, which are of great interest for avalanche study. This digital terrain model was generated after processing LiDAR data obtained from a scanning campaign for the analyzed area with the Riegl LMS Q680i LiDAR system, located aboard the Hawker Beechcraft King Air C90 GTx aircraft from INCAS. The result of the analysis consisted in mapping the risk of avalanches in the Râmeț mountain area in Alba County.
Improved Timing for better performance of distributed data acquisition systems - a further refinement
Authors: PANAIT Alexandru Marius
Published: March 2022

Continuing the works debuted in the previous work “Improved Timing for better performance of distributed data acquisition systems” the present paper refines and revisits the concept of a local oscillator with GPS corrections as a source of long-term stable reference clock signals with direct application in distributed data acquisition systems. The system as described herein can generate precise and repeatable clock source signals for trigger and sync of various data acquisition equipment when used in mixed and distributed architectures. These timing signals are a vital part of data acquisition as oftentimes raw data is processed as time series and correlations are made based on timestamps. This paper details improvements in implementation of a cost-effective high precision time base (reference clock) using a GPS receiver as a primary time source and a local high precision real time clock as a secondary oscillator. The improvements to the previous version come both from hardware refinements and from updated software with reduced latencies and reconfigured structure that allows for compensation of internal delays and internal process offsets.
Rogue waves in nonlinear optics
Authors: Tlidi M. , Taki M.
Published: March 2022

Understanding the phenomenon of rogue wave formation, often called extreme waves, in diverse branches of nonlinear science has become one of the most attractive domains. Given the great richness of the new results and the increasing number of disciplines involved, we are focusing here on two pioneering fields: hydrodynamics and nonlinear optics. This tutorial aims to provide basic background and the recent developments on the formation of rogue waves in various systems in nonlinear optics, including laser physics and fiber optics. For this purpose we first discuss their formation in conservative systems, because most of the theoretical and analytical results have been realized in this context. By using a multiple space–time scale analysis, we review the derivation of the nonlinear Schrödinger equation from Maxwell’s equations supplemented by constitutive equations for Kerr materials. This fundamental equation describes the evolution of a slowly varying envelope of dispersive waves. This approximation has been widely used in the majority of systems, including plasma physics, fluid mechanics, and nonlinear fiber optics. The basic property of this generic model that governs the dynamics of many conservative systems is its integrability. In particular, we concentrate on a nonlinear regime where classical prototypes of rogue wave solutions, such as Akhmediev breathers, Peregrine, and Ma solitons are discussed as well as their experimental evidence in optics and hydrodynamics. The second part focuses on the generation of rogue waves in one- and two-dimensional dissipative optical systems. Specifically, we consider Kerr-based resonators for which we present a detailed derivation of the Lugiato–Lefever equation, assuming that the resonator length is shorter than the space scales of diffraction (or the time scale of the dispersion) and the nonlinearity. In addition, the system possesses a large Fresnel number, i.e., a large aspect ratio so that the resonator boundary conditions do not alter the central part of the beam. Dissipative structures such as solitons and modulational instability and their relation to frequency comb generation are discussed. The formation of rogue waves and the control employing time-delayed feedback are presented for both Kerr and semiconductor-based devices. The last part presents future perspectives on rogue waves to three-dimensional dispersive and diffractive nonlinear resonators.
Propagation dynamics of Laguerre–Gaussian beams in the fractional Schrödinger equation with noise disturbance
Authors: Zhou Weijun , Liu Aixin , Huang Xianwei , Bai Yanfeng , Fu Xiquan
Published: March 2022

The evolution of Laguerre–Gaussian (LG) beams in the fractional Schrödinger equation (FSE) with Gaussian noise disturbance is numerically investigated. Without noise disturbance, the peak intensity of LG beams increases with the increment of radial or azimuthal indices, and the turning point of the peak intensity between different radial indices exists. As propagation distance gets longer, the intensity of the outermost sub-lobe exceeds that of the main lobe. When Gaussian noise is added, for a given noise level, the stability of peak intensity is enhanced as the Lévy index increases, while the center of gravity shows the opposite phenomenon. Moreover, the increment of the radial index can weaken the stability of the center of gravity. We also investigate the stability of the peak intensity of Airy beams in the FSE, and generally, the stability of LG beams is better than that of Airy beams. All these properties show that LG beams modeled by the FSE have potential applications in optical manipulation and communications.
Photonic topological insulators in bianisotropic metamaterials
Authors: Chern Ruey-Lin , Shen Yang-Jie , Yu You-Zhong
Published: March 2022

We analyze the photonic topological phases in bianisotropic metamaterials characterized by a lossless and reciprocal magnetoelectric tensor. The underlying medium is considered a topological insulator that supports a pair of counterpropagating helical edge states. By introducing the pseudospin basis, the photonic system can be described by the spin-orbit Hamiltonians with spin 1, which result in nonzero spin Chern numbers that determine the topological properties. Surface modes at the interface between two bianisotropic media with opposite chirality exist in their common band gap, which are represented by elliptic or hyperbolic equations. In particular, two branches of hyperbolic surfaces are degenerate at the frequency where the chiral nihility occurs, which depict the helical nature of edge states between two distinct topological phases. Topological features of the bianisotropic metamaterials are further illustrated with the robust transport of surface modes at an irregular boundary.
All-optical reconstruction of three-band transition dipole moments by the crystal harmonic spectrum from a two-color laser pulse
Authors: Qiao Yue , Huo Yan-Qiu , Jiang Shi-Cheng , Yang Yu-Jun , Chen Ji-Gen
Published: March 2022

When a bulk solid is irradiated by an intense laser pulse, transition dipole moments (TDMs) between different energy bands have an important influence on the ultra-fast dynamic process. In this paper, we propose a new all-optical method to reconstruct the k-dependent TDMs between multi-bands using a crystal high-order harmonic generation (HHG). Taking advantage of an obvious separation of bandgaps between three energy bands of an MgO crystal along the <001 > direction, a continuous harmonic spectrum with two plateaus can be generated by a two-color laser pulse. Furthermore, the first harmonic platform is mainly dominated by the polarization between the first conduction band and the valence band, and the second one is largely attributed to the interband HHG from the second conduction band and the valence band. Therefore, the harmonic spectrum from a single quantum trajectory can be adopted to map TDMs between the first, second conduction bands, and the valence one. Our work is of great significance for understanding the instantaneous properties of solid materials in the strong laser field, and will strongly promote the development of the HHG detection technology.
Implementation of field two-way quantum synchronization of distant clocks across a 7 km deployed fiber link
Authors: Quan Runai , Hong Huibo , Xue Wenxiang , Quan Honglei , Zhao Wenyu , Xiang Xiao , Liu Yuting , Cao Mingtao , Liu Tao , Zhang Shougang , Dong Ruifang
Published: March 2022

The two-way quantum clock synchronization has been shown to provide femtosecond-level synchronization capability and security against symmetric delay attacks, thus becoming a prospective method to compare and synchronize distant clocks with enhanced precision and safety. In this letter, a field test of two-way quantum synchronization between a H-maser and a Rb clock linked by a 7 km-long deployed fiber is implemented by using time-energy entangled photon-pair sources. Limited by the intrinsic frequency stability of the Rb clock, the achieved time stability at 30 s is measured as 32 ps. By applying a fiber-optic microwave frequency transfer technology to build frequency syntonization between the separated clocks, the limit set by the intrinsic frequency stability of the Rb clock is overcome. A significantly improved time stability of 1.9 ps at 30 s is achieved, which is mainly restrained by the low number of acquired photon pairs due to the low sampling rate of the utilized coincidence measurement system. Such implementation demonstrates the high practicability of the two-way quantum clock synchronization method for promoting field applications.
Design study for an efficient semiconductor quantum light source operating in the telecom C-band based on an electrically-driven circular Bragg grating
Authors: Barbiero Andrea , Huwer Jan , Skiba-Szymanska Joanna , Müller Tina , Stevenson R. Mark , Shields Andrew J.
Published: March 2022

The development of efficient sources of single photons and entangled photon pairs emitting in the low-loss wavelength region around 1550 nm is crucial for long-distance quantum communication. Moreover, direct fiber coupling and electrical carrier injection are highly desirable for deployment in compact and user-friendly systems integrated with the existing fiber infrastructure. Here we present a detailed design study of circular Bragg gratings fabricated in InP slabs and operating in the telecom C-band. These devices enable the simultaneous enhancement of the X and XX spectral lines, with collection efficiency in numerical aperture 0.65 close to 90% for the wavelength range 1520 - 1580 nm and Purcell factor up to 15. We also investigate the coupling into a single mode fiber, which exceeds 70% in UHNA4. Finally, we propose a modified device design directly compatible with electrical carrier injection, reporting Purcell factors up to 20 and collection efficiency in numerical aperture 0.65 close to 70% for the whole telecom C-band.
Fast aerial image model for EUV lithography using the adjoint fully convolutional network
Authors: Lin Jiaxin , Dong Lisong , Fan Taian , Ma Xu , Wei Yayi
Published: March 2022

The effects of thick-mask and oblique incidence in extreme ultraviolet (EUV) lithography system make the aerial image calculation a challenging task. This paper develops a fast EUV lithography aerial image model based on a new kind of deep learning framework called adjoint fully convolutional network (AFCN). The AFCN consists of two adjoint data paths to respectively recover the real part and imaginary part of the complex mask diffraction-near-field (DNF). The feature-swapping technique is introduced to exchange the information between the real and imaginary data paths. The AFCN is trained based on a pre-calculated rigorous thick-mask DNF dataset. Given the estimated thick-mask DNF, the Abbe’s method is used to calculate the aerial image of the partially coherent lithography system. Compared to the traditional non-parametric kernel regression method, the proposed model reduces the error by more than 80% and achieves 25-fold improvement in computational efficiency.
Electromagnetic origin of femtosecond laser-induced periodic surface structures on GaP crystals
Authors: Lu Min , Cheng Ke , Qin Ziyao , Ju Jiaqi , Liu Jukun , Huo Yanyan
Published: March 2022

The formations of different types of laser-induced periodic surface structures (LIPSS) on the surface of GaP crystals with different laser fluence are researched in experiments. The transition from the high spatial frequency LIPSS (HSFL) to the low spatial frequency LIPSS (LSFL) occurred as the number of the irradiated laser pulse increased. The finite difference time domain method combined with the holographic ablation model is used to simulate the LIPSS formation under the irradiation of multiple pulses. Different types of ripples are predicted by the electromagnetic approach. Results demonstrate that the electromagnetic origins of HSFL and LSFL are due to the interference of incident field and the scattering field under the multi-pulse irradiation.
Quantitative demodulation of distributed low-frequency vibration based on phase-shifted dual-pulse phase-sensitive OTDR with direct detection
Authors: Liu Shuaiqi , Shao Liyang , Yu Fei-Hong , Xu Weijie , Vai Mang I. , Xiao Dongrui , Lin Weihao , Hu Jie , Zhao Fang , Wang Guoqing , Wang Weizhi , Liu Huanhuan , Shum Perry P. , Wang Feng
Published: March 2022

Phase-sensitive optical time-domain reflectometry (Φ-OTDR) has been proposed for distributed vibration sensing purpose over recent years. Emerging applications, including seismic and hydroacoustic wave detection, demand accurate low-frequency vibration reconstruction capability. We propose to use the direct-detection Φ-OTDR configuration to achieve quantitative demodulation of external low-frequency vibrations by phase-shifted dual-pulse probes. Simultaneous pulsing and phase shifting modulation is realized with a single acousto-optic modulator to generate such probes, relaxing the need for an additional optical phase modulator. In the experiments, vibrations with frequency as low as 0.5 Hz are successfully reconstructed with 10 m spatial resolution and 35 dB signal-to-noise ratio. Excellent linearity and repeatability are demonstrated between the optical phase demodulation results and the applied vibration amplitudes. The proposed method is capable of quantitative demodulation of low-frequency vibrations with a cost-effective system configuration and high computation efficiency, showing potential for commercial applications of distributed seismic or hydroacoustic wave acquisition.
Improved performance of GaN-based blue laser diodes using asymmetric multiple quantum wells without the first quantum barrier layer
Authors: Liang Feng , Zhao Degang , Liu Zongshun , Chen Ping , Yang Jing
Published: March 2022

An asymmetric multiple quantum well (MQW) without the first quantum barrier layer is designed, and its effect on the device performance of GaN-based blue LDs has been studied experimentally and theoretically. It is found that compared with LD using symmetrical multiple quantum well, device performance is improved significantly by using asymmetric MQW, i.e. having a smaller threshold current density, a higher output optical power and a larger slope efficiency. The threshold current density decreases from 1.28 kA/cm2 to 0.86 kA/cm2, meanwhile, the optical power increases from 1.77 W to 2.52 W, and the slope efficiency increases from 1.15 W/A to 1.49 W/A. The electroluminescence characteristics below the threshold current demonstrate that asymmetric MQW is more homogeneous due to the suppressed strain and piezoelectric field. Furthermore, theoretical calculation demonstrates that the enhancement of electron injection ratio and reduction in optical loss are another reason for the improvement of device performance, which is attributed to a smaller electron potential barrier and a more concentrated optical field distribution in the asymmetric structure, respectively. The new structure design with asymmetric MQW is concise for epitaxial growth, and it would also be a good possible choice for GaN-based LDs with other lasing wavelengths.
Third-order orbital angular momentum pulse generation from a passively Q-switched fiber laser
Authors: Xiao Rongli , Tu Jiajing , Li Wei , Gao Shecheng , Wen Tianjin , Du Cheng , Zhou Ji , Zhang Bin , Liu Weiping , Li Zhaohui
Published: March 2022

We propose and demonstrate an all-fiber passively Q-switched laser generating a third-order orbital angular momentum (OAM) pulse by introducing a few-mode long-period fiber grating (LPFG) into the laser cavity. The LPFG with asymmetric cross structure and strong refractive index modulation overcomes the coupling issue between the fundamental and the third-azimuthal-order (LP31 or OAM3) modes and realizes their direct conversion. A homemade graphene-based saturable absorber is used to realize Q-switched operation. The laser operates at a center wavelength of 1548.2nm, with a 3 dB spectral bandwidth of 0.4nm, and the OAM+3 and OAM-3 beams can achieve the purity of 90.0% and 90.2%, respectively. This all-fiber Q-switched laser has simple and compact structure and high purity of OAM±3 beams, which has potential applications in the fields of optical tweezers and material processing.
TE-mode magneto-optical isolator based on an asymmetric microring resonator under a unidirectional magnetic field
Authors: Liu Shuyuan , Shoji Yuya , Mizumoto Tetsuya
Published: March 2022

Optical isolators are necessary components in photonic integrated circuits to ensure system stability by blocking the back-reflected light waves. In this study, a transverse electric mode magneto-optical isolator based on an asymmetric microring resonator without additional polarization rotators in series is demonstrated. Cerium-substituted yttrium iron garnet was integrated with silicon-on-insulator substrates by wafer bonding to break the Lorentz reciprocity on-chip after applying a unidirectional magnetic field. The isolator shows a 22 dB isolation ratio and a 4.3 dB insertion loss at an operation wavelength of 1572.62 nm.
Inverse design assisted coherent optical lattices
Authors: Kouznetsov Dmitry , Arisev Ongun , Van Dorpe Pol , Verellen Niels
Published: March 2022

We explore the use of inverse design methods for the generation of periodic optical patterns in photonic integrated circuits. A carefully selected objective function based on the integer lattice method, which is an algebraic technique for optical lattice generation, is shown to be key for successful device design. Furthermore, we present a polychromatic pattern generating device that switches between optical lattices with different symmetry and periodicity depending on the operating wavelength. Important links are drawn between optical coherent lattices and optical potentials, pointing towards practical applications in the fields of quantum simulations and computing, optical trapping, and bio-sensing.